View source for Downtown Seattle Transit Tunnel

{{short description|Rail tunnel in Seattle, Washington, United States}}
{{Redirect|DSTT|the Nintendo DS storage device|DSTT (storage device)|the University of Dundee's division|Division of Signal Transduction Therapy}}
{{featured article}}
{{Use mdy dates|date=May 2017}}
{{Infobox tunnel
| name          = Downtown Seattle Transit Tunnel
| image         = File:Westlake Station DSTT portal.jpg
| image_size    =
| alt           = Two large tunnel tubes with rails embedded in concrete running into them
| caption       = The southbound portal at [[Westlake station (Sound Transit)|Westlake station]]
| official_name =
| other_name    = Metro Bus Tunnel
| line          = {{unbulleted list|{{rint|Seattle|Line 1}} [[1 Line (Sound Transit)|1&nbsp;Line]]|{{rint|Seattle|Line 2}} [[2 Line (Sound Transit)|2&nbsp;Line]] ''(future)''}}
| location      = [[Seattle]], [[Washington (state)|Washington]], U.S. 
| system        = [[Link light rail]]
| start         = 5th Avenue and [[Pine Street]]
| end           = 5th Avenue S and S Jackson Street
| stations      = 4
| startwork     = {{start date|1987|03|06}}
| opened        = {{start date|1990|09|15}}
| rebuilt       = 2005–2007
| reopened      = {{start date|2007|09|24}}
| owner         = {{ublist|[[Sound Transit]] (2022–)|King County Metro (1987–2022)}}
| operator      = Sound Transit
| traffic       = [[Light rail]]
| length        = {{convert|1.3|mi|km}}<ref name="HL-Opening">{{cite web |last=Crowley |first=Walt |author-link=Walt Crowley |date=October 1, 2000 |title=Bus service begins in downtown Seattle transit tunnel on September 15, 1990. |url=http://www.historylink.org/File/2702 |work=[[HistoryLink]] |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20161019081347/http://www.historylink.org/File/2702 |archive-date=October 19, 2016}}</ref>
| linelength    =
| tracklength   =
| notrack       = [[Double track|Double]]
| gauge         = {{RailGauge|ussg}}
| el            = 1,500 [[Volt|V]] [[Direct current|DC]], [[Overhead lines|Overhead catenary]]<ref>{{cite journal |last=Middleton |first=William D. |author-link=William D. Middleton |date=April 1, 2006 |title=Sound Transit builds for LRT: Projected growth over the next 25 years is driving the Seattle region's rapid push to expand light rail. |journal=[[Railway Age]] |location=Chicago, Illinois |publisher=[[Simmons-Boardman Publishing]] |pages=43–45 |issn=0033-8826 |oclc=1586268 |url=http://www.railwayage.com/B/feature2.html |url-status=dead |archive-url=https://web.archive.org/web/20060502105012/http://www.railwayage.com/B/feature2.html |archive-date=May 2, 2006 |access-date=May 27, 2017}}</ref>
| speed         = {{convert|30|mph|kph|abbr=on}}
| hielevation   =
| lowelevation  =
| height        =
| width         = {{convert|18|ft|m|abbr=on}}
| grade         =
| map           = {{Downtown Seattle Transit Tunnel}}
| extra         = {{collapsed infobox section begin|Interactive map|titlestyle=background-color:#eee}}{{maplink|frame=yes|plain=yes|frame-align=center|frame-width=250|frame-height=290|frame-lat=47.605|frame-long=-122.333|zoom=13|type=line|raw={{Wikipedia:Map data/Wikipedia KML/Downtown Seattle Transit Tunnel}}}}
{{collapsed infobox section end}}
}}

The '''Downtown Seattle Transit Tunnel''' ('''DSTT'''), also referred to as the '''Metro Bus Tunnel''', is a {{convert|1.3|mi|km|adj=mid|-long}} pair of [[public transit]] [[tunnel]]s in [[Seattle]], [[Washington (state)|Washington]], United States. The [[double track|double-track]] tunnel and its four stations serve [[Link light rail]] trains on the [[1 Line (Sound Transit)|1&nbsp;Line]] as it travels through [[Downtown Seattle]]. It runs west under [[Pine Street]] from 9th Avenue to 3rd Avenue, and south under 3rd Avenue to South Jackson Street. 1&nbsp;Line trains continue north from the tunnel to [[Lynnwood City Center station|Lynnwood City Center]] and south through the [[Rainier Valley, Seattle|Rainier Valley]] past [[Seattle–Tacoma International Airport]] to [[Angle Lake station]] as part of [[Sound Transit]]'s [[light rail]] network.

The DSTT was used only by [[Transit bus|buses]] from its opening in 1990 until 2005, and shared by buses and [[light rail]] from 2009 until 2019. Bus routes from [[King County Metro]] and [[Sound Transit Express]] left the tunnel north via [[Interstate 5 in Washington|Interstate 5]], south via the [[SODO Busway]], or east via [[Interstate 90 in Washington|Interstate 90]]. It was owned by King County Metro and shared with Sound Transit through a joint-operating agreement signed in 2002; Sound Transit assumed full ownership in 2022. The Downtown Seattle Transit Tunnel was one of two tunnels in the United States shared by buses and trains, the other being the [[Mount Washington Transit Tunnel]] in [[Pittsburgh]], and was the only one in the United States with shared stations.

Though proposals for a [[rapid transit]] tunnel under 3rd Avenue were introduced in the 1910s and 1920s, planning for the modern bus and rail Metro Bus Tunnel only began in 1974. The King County Metro Council approved the bus tunnel proposal in November 1983, but construction did not begin until March 1987. The tunnel between [[Convention Place station|Convention Place]] and [[Westlake station (Sound Transit)|Westlake]] stations was built using the [[cut-and-cover]] method, closing Pine Street for 19 months and disrupting access to the retail core. The segment from Westlake to the [[International District/Chinatown station|International District]] was bored with two [[tunnel-boring machine]]s, heading north from [[Union Station (Seattle)|Union Station]] and finishing within a month of each other. Tests of normal buses and the [[Breda Costruzioni Ferroviarie|Breda]] [[dual-mode bus]]es built specifically for tunnel routes began in March 1989; tunnel construction was declared complete in June 1990, at a cost of $469 million. Light rail tracks were installed in anticipation of future rapid transit service through the tunnel, but were later found to be poorly insulated and unusable for Link light rail. [[Soft opening]]s and public previews of the five tunnel stations were held from August 1989 to September 1990, with regular bus service beginning on September 15, carrying 28,000 daily passengers in its first year of operation. For the next several years, until June 2004, service in the tunnel was provided exclusively by dual-mode buses, which ran as [[trolleybus]]es in the tunnel{{spaced ndash}}like the city's [[Trolleybuses in Seattle|extensive trolleybus system]]{{spaced ndash}}and as diesel buses on surface streets and freeways.

The tunnel was closed on September 24, 2005, for modification to accommodate both buses and Sound Transit's Central Link (now the 1&nbsp;Line) light rail trains with shared lanes and platforms. The roadway was lowered by {{convert|8|in|cm}} and other improvements were made to prepare for light rail service. New [[hybrid electric bus]]es were moved into the tunnel to replace the Breda fleet, as the [[overhead wire]] was replaced for light rail trains. The tunnel reopened on September 24, 2007, and light rail service began on July 18, 2009. A stub tunnel, branching from the main tunnel, was constructed under Pine Street to allow light rail trains to stop and reverse direction; it was later used as the first segment of a [[University Link|light rail extension]] to [[Capitol Hill, Seattle|Capitol Hill]] and the [[University of Washington]] that opened in 2016. Convention Place station was closed permanently on July 21, 2018, to make way for an expansion of the [[Washington State Convention Center]] that would also restrict bus access to the tunnel. On March 23, 2019, bus service in the tunnel ceased and its remaining seven routes were moved to surface streets.

==Route and stations==
[[File:Seattle - Pioneer Square Station July 2009.jpg|thumb|left|[[Pioneer Square station]], located near the tunnel's southern end|alt=A train in a large, cavernous underground station. A bus can be seen in the background heading the opposite direction.]]

The {{convert|1.3|mi|km|adj=mid|-long}}, {{convert|18|ft|m|adj=mid|-diameter}}<ref name="HL-Excavation">{{cite web |last=Crowley |first=Walt |date=January 1, 2000 |title=Workers complete primary excavation of downtown Seattle transit tunnel on April 8, 1988. |url=http://www.historylink.org/File/2701 |work=HistoryLink |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20161019081418/http://www.historylink.org/File/2701 |archive-date=October 19, 2016}}</ref> tunnel is used by the [[1 Line (Sound Transit)|1&nbsp;Line]] between [[Westlake station (Sound Transit)|Westlake]] and [[International District/Chinatown station|International District/Chinatown]] stations.<ref name="LinkSchedule">{{cite web |title=Link light rail schedule |url=http://www.soundtransit.org/schedules/link-light-rail |date=September 10, 2016 |publisher=[[Sound Transit]] |access-date=September 11, 2016 |url-status=dead |archive-url=https://web.archive.org/web/20150809074021/http://www.soundtransit.org/Schedules/Link-light-rail |archive-date=August 9, 2015}}</ref> Entrances at several tunnel stations are built into nearby buildings with [[variable-message sign]]s over the stairs and elevators leading to the [[mezzanine]]s. A total of 11 [[wheelchair]]-[[Accessibility|accessible]] elevators connect the tunnel stations to the surface.<ref>{{cite map |date=July 2021 |title=Downtown Seattle Accessible Map and Transit Guide |url=https://kingcounty.gov/en/-/media/king-county/depts/metro/maps/seattle/09022023/pdf/seattle-accessible-map.pdf |publisher=King County Metro, Sound Transit |accessdate=January 23, 2024}}</ref><ref>{{cite news |last=Gilje |first=Shelby |date=September 27, 1990 |title=Looking out for rights of the disabled |page=F3 |url=http://community.seattletimes.nwsource.com/archive/?date=19900927&slug=1095407 |work=[[The Seattle Times]] |access-date=April 25, 2015 |url-status=live |archive-url=https://web.archive.org/web/20160304084522/http://community.seattletimes.nwsource.com/archive/?date=19900927&slug=1095407 |archive-date=March 4, 2016}}</ref> The deepest of the tunnel stations are {{convert|60|ft|m}} below street level and consist of two [[side platform]]s, two tracks, and a former bus passing lane in the middle.<ref name="HL-031987">{{cite web |last=Crowley |first=Walt |date=October 1, 2000 |title=Metro Transit begins excavating downtown Seattle transit tunnel on March 6, 1987. |url=http://www.historylink.org/File/2700 |work=HistoryLink |access-date=April 17, 2011 |url-status=live |archive-url=https://web.archive.org/web/20161019071952/http://www.historylink.org/File/2700 |archive-date=October 19, 2016}}</ref><ref>{{cite report |title=TCRP Report 90: Bus Rapid Transit, Vol. 1: Case Studies in Bus Rapid Transit |chapter=Seattle, Washington Brief: Metro Bus Travel |chapter-url=http://onlinepubs.trb.org/onlinepubs/tcrp/tcrp90v1_cs/Seattle.pdf |publisher=[[Transportation Research Board]] |year=2004 |oclc=52902995 |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202015428/http://onlinepubs.trb.org/onlinepubs/tcrp/tcrp90v1_cs/Seattle.pdf |archive-date=February 2, 2017}}</ref> Since 2019, the stations have also had signs with numbered exits to aid in rider wayfinding.<ref>{{cite news |last=Metzger |first=Katie |date=November 21, 2019 |title=New exit strategy for downtown transit tunnel |url=https://www.soundtransit.org/blog/platform/new-exit-strategy-downtown-transit-tunnel |work=The Platform |publisher=Sound Transit |access-date=July 12, 2021}}</ref> As part of the city's [[public art]] program that began in 1973, the Downtown Seattle Transit Tunnel and its stations were furnished with $1.5 million (equivalent to ${{inflation|US|1.5|1984|r=0}}&nbsp;million in {{Inflation-year|US}} dollars){{inflation-fn|US}} in artwork by 25 artists commissioned by King County Metro.<ref>{{cite web |title=Take time to experience the art of bus riding |url=http://metro.kingcounty.gov/tops/tunnel/tunnel-stationart.html |publisher=King County Metro |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141006192819/http://metro.kingcounty.gov/tops/tunnel/tunnel-stationart.html |archive-date=October 6, 2014}}</ref><ref name="SeaTimes-Art1990">{{cite news |last=Mathieson |first=Karen |date=September 12, 1990 |title=Tunnel visions: Bus labyrinth beneath Seattle spawns gallery |page=C1 |url=http://community.seattletimes.nwsource.com/archive/?date=19900912&slug=1092772 |work=The Seattle Times |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141006100153/http://community.seattletimes.nwsource.com/archive/?date=19900912&slug=1092772 |archive-date=October 6, 2014}}</ref>

The northern portal, formerly accessible to buses at street level from Olive Way, and from [[Interstate 5 in Washington|Interstate 5]] via an [[Reversible lane|express lane]] ramp, was the former [[Convention Place station]] at the intersection of 9th Avenue and Pine Street near the [[Washington State Convention Center]]. Until its closure in 2018, Convention Place was the only bus-exclusive station in the tunnel, and consisted of four sheltered platforms in a sunken, open-air [[layover]] space below street level.<ref name="CPS">{{cite map |publisher=King County Metro Transit |date=September 2007 |title=Transit Tunnel: Convention Place Station |url=http://metro.kingcounty.gov/tops/tunnel/pdf/ConvPlaceMap.pdf |format=PDF |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20150421021739/http://metro.kingcounty.gov/tops/tunnel/pdf/ConvPlaceMap.pdf |archive-date=April 21, 2015}}</ref> Buses entered the tunnel from 9th Avenue and passed under the historic [[Camlin Hotel]], before joining the [[University Link Tunnel]] used by light rail trains headed north for three blocks under [[Pine Street]] to [[Capitol Hill station]].<ref>{{cite web |title=Pine Street Stub Tunnel |url=http://www.soundtransit.org/sites/default/files/documents/pdf/archived_projects/20121130_pinestreetstubtunnel.pdf |date=November 30, 2012 |publisher=Sound Transit |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20150909221125/http://www.soundtransit.org/sites/default/files/documents/pdf/archived_projects/20121130_pinestreetstubtunnel.pdf |archive-date=September 9, 2015}}</ref><ref name="TunnelMap">{{cite map |publisher=King County Metro Transit |title=Downtown Seattle Transit Tunnel |url=http://metro.kingcounty.gov/maps/pdf/downtown-seattle-tunnel-map.pdf |format=PDF |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141006083234/http://metro.kingcounty.gov/maps/pdf/downtown-seattle-tunnel-map.pdf |archive-date=October 6, 2014}}</ref>

The DSTT enters Westlake station under Pine Street between 3rd and 6th avenues, located between the [[Westlake Center]] shopping mall and [[Westlake Park (Seattle)|Westlake Park]]. The station features a two-block-long mezzanine with exits to Pine Street and several retailers, including the Westlake Center, the former [[The Bon Marché]] flagship store, and the [[Nordstrom Downtown Seattle|Nordstrom Building]], as well as the former King County Metro [[customer service]] center.<ref>{{cite web |title=Metro Customer Services |url=http://metro.kingcounty.gov/cs/index.html#visit |date=January 1, 2013 |publisher=King County Metro |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20150214210431/http://metro.kingcounty.gov/cs/index.html |archive-date=February 14, 2015}}</ref> The area around the station is known as the Westlake Hub, with connections to the [[South Lake Union Streetcar]] and the [[Seattle Center Monorail]] as well as the King County Metro and Sound Transit buses.<ref>{{cite map |publisher=King County Metro Transit |date=September 2007 |title=Transit Tunnel: Westlake Station |url=http://metro.kingcounty.gov/tops/tunnel/pdf/WestlakeMap.pdf |format=PDF |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20150221055144/http://metro.kingcounty.gov/tops/tunnel/pdf/WestlakeMap.pdf |archive-date=February 21, 2015}}</ref> Leaving Westlake Station, the bored set of twin tunnels turn south under Century Square to follow 3rd Avenue and its [[transit mall]] through the [[central business district]], parallel to the shoreline of [[Elliott Bay]].<ref name="TunnelMap"/>

Three blocks south of Pine Street, buses and trains enter [[Symphony station (Sound Transit)|Symphony station]], located between Union and Seneca streets adjacent to [[Benaroya Hall]] and [[1201 Third Avenue]] in the financial district. The station has a split mezzanine, with entrances to 2nd Avenue and University Street accessible from the north half, and an entrance to Seneca Street from the south half.<ref>{{cite map |publisher=King County Metro Transit |date=September 2007 |title=Transit Tunnel: University Street Station |url=http://metro.kingcounty.gov/tops/tunnel/pdf/UniversityMap.pdf |format=PDF |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20150412061756/http://metro.kingcounty.gov/tops/tunnel/pdf/UniversityMap.pdf |archive-date=April 12, 2015}}</ref> From Symphony, the tunnel continues under 3rd Avenue for five blocks, entering the [[Pioneer Square, Seattle|Pioneer Square]] neighborhood and [[Historic districts in the United States|historic district]]. At this point, 3rd Avenue passes several of Seattle's skyscrapers, including the historic [[Seattle Tower]], [[Safeco Plaza (Seattle)|Safeco Plaza]], the [[Fourth and Madison Building]] and the [[Wells Fargo Center (Seattle)|Wells Fargo Center]].<ref name="TunnelMap"/> Within Symphony station, the tunnel passes over the century-old [[Great Northern Tunnel]] with a clearance of {{convert|15|ft|m|0}}.<ref name="SeaTimes-TunnelHist">{{cite news |last=Mapes |first=Lynda V. |date=December 10, 2011 |title=Tunnels: Seattle's boring past filled with thrills |url=http://old.seattletimes.com/html/pacificnw/2016900003_pacificptunnels11.html |work=The Seattle Times |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20170202060756/http://old.seattletimes.com/html/pacificnw/2016900003_pacificptunnels11.html |archive-date=February 2, 2017}}</ref>

[[Pioneer Square station]] is located between Cherry Street and Yesler Way, with four entrances to nearby streets and Prefontaine Place serving two mezzanines. The station serves the [[administrative center]]s of the Seattle and King County governments, located within walking distance of [[Seattle City Hall]], the [[Seattle Municipal Tower]], the [[King County Courthouse]] and the [[King County Administration Building]], as well as other major buildings, including [[Smith Tower]], [[Columbia Center]] and the [[Alaska Building]].<ref>{{cite map |publisher=King County Metro Transit |date=September 2007 |title=Transit Tunnel: Pioneer Square Station |url=http://metro.kingcounty.gov/tops/tunnel/pdf/PioneerSquareMap.pdf |format=PDF |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141222040428/http://metro.kingcounty.gov/tops/tunnel/pdf/pioneersquaremap.pdf |archive-date=December 22, 2014}}</ref> From Pioneer Square, the tunnel travels down a 5.5% [[grade (slope)|grade]] to cross {{convert|4.5|ft|m|1}} under the Great Northern Tunnel at a 45-degree angle near the intersection of 4th Avenue South and South Washington Street, briefly descending below [[sea level]],<ref>{{cite web |title=Pioneer Square Station—the Pioneering Spirit |url=http://metro.kingcounty.gov/tops/tunnel/ts-pioneer.html |url-status=dead |archive-url=https://web.archive.org/web/20150201055538/http://metro.kingcounty.gov/tops/tunnel/ts-pioneer.html |archive-date=February 1, 2015 |publisher=King County Metro |access-date=January 2, 2015}}</ref> before turning [[Cardinal direction|cardinal south]] into the [[International District, Seattle|International District]] neighborhood.<ref name="TunnelMap"/><ref name="SeaTimes-TunnelHist"/><ref name="Moles">{{cite news |last=Lane |first=Bob |date=September 14, 1987 |title=Mechanical Moles |page=D1 |work=The Seattle Times |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5327C20522432?p=AMNEWS |url-access=subscription |via=[[NewsBank]] |access-date=September 30, 2014}}</ref>

International District/Chinatown station, the southernmost tunnel station, is partially open-air and located immediately below a public plaza at [[Union Station (Seattle)|Union Station]]. The station has connections to [[Amtrak]] and [[Sounder commuter rail]] at [[King Street Station (Seattle)|King Street Station]] a block to the west, accessible through the Weller Street Bridge, as well as the [[First Hill Streetcar]] on Jackson Street, stopping east of 5th Avenue South.<ref>{{cite web |author=[[Seattle Department of Transportation]] |date=July 2013 |title=Seattle Streetcar: First Hill Line |url=http://www.seattlestreetcar.org/docs/trans/FH_brochure_english_web.pdf |publisher=Seattle Streetcar |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20131218184227/http://www.seattlestreetcar.org/docs/trans/FH_brochure_english_web.pdf |archive-date=December 18, 2013}}</ref><ref>{{cite news |last=Lindblom |first=Mike |date=July 11, 2009 |title=International District/Chinatown Station is switching point for many commuters |url=http://old.seattletimes.com/html/localnews/2009261916_stinternational26m.html |work=The Seattle Times |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20170202060904/http://old.seattletimes.com/html/localnews/2009261916_stinternational26m.html |archive-date=February 2, 2017}}</ref> Other attractions near the station include [[Lumen Field]] to the west and [[Uwajimaya]] a block to the southeast.<ref name="TunnelMap"/><ref>{{cite map |publisher=King County Metro Transit |date=September 2007 |title=Transit Tunnel: International District/Chinatown Station |url=http://metro.kingcounty.gov/tops/tunnel/pdf/ID_ChinatownMap.pdf |format=PDF |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20151123200507/http://metro.kingcounty.gov/tops/tunnel/pdf/ID_ChinatownMap.pdf |archive-date=November 23, 2015}}</ref> South of the station, the light rail tracks and bus lanes were formerly separated by [[railway signal]]s at an underground bus layover and [[staging area]] next to the tunnel [[Rest area|comfort room]] for bus drivers.<ref name="TheBook">{{cite book |date=February 2011 |title=The Book: Transit Operating Handbook |pages=726–729 |url=https://seattletransitblog.com/wp-content/uploads/2011/06/TheBookFeb2011_rev_01272011.pdf |publisher=King County Metro |via=Seattle Transit Blog |access-date=July 17, 2017}}</ref> The southern portal of the tunnel is located under the intersection of Airport Way and 5th Avenue South at the western terminus of the former [[Interstate 90 in Washington|Interstate 90]] [[Reversible lane|express lanes]] for [[High-occupancy vehicle lane|high-occupancy vehicles]].<ref>{{cite map |publisher=[[Washington State Department of Transportation]] |title=I-90 Express Lanes Map |url=http://www.wsdot.wa.gov/Northwest/King/ExpressLanes/I90map.htm |access-date=September 30, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20141006022016/http://www.wsdot.wa.gov/Northwest/King/ExpressLanes/I90Map.htm |archive-date=October 6, 2014}}</ref> Until bus operations ceased, southbound routes continued from the tunnel in separated lanes on the [[SODO Busway]], while eastbound buses used a set of ramps that traveled onto the Interstate 90 express lanes.<ref>{{cite web |date=September 2018 |title=Rainier Freeway Station Closes Sept. 22, 2018 |url=https://www.soundtransit.org/sites/default/files/I-90_Link-One-SheetD8.pdf |publisher=Sound Transit |access-date=December 7, 2018}}</ref> The eastbound ramps will be retrofitted for the [[East Link Extension (Sound Transit)|East Link]] light rail service that begins in 2025 on the 2&nbsp;Line.<ref>{{cite news |last=Lindblom |first=Mike |date=August 24, 2023 |title=Eastside-only light rail should open in March, Sound Transit says |url=https://www.seattletimes.com/seattle-news/transportation/eastside-only-light-rail-should-open-march-2024-sound-transit-says/ |work=The Seattle Times |accessdate=August 24, 2023}}</ref><ref>{{cite web |date=November 2010 |title=East Link Light Rail Segment A: Seattle, Mercer Island via I-90 |url=http://www.soundtransit.org/Documents/pdf/projects/eastlink/factsheets/A_Sea_I90_110510.pdf |page=1 |url-status=dead |archive-url=https://web.archive.org/web/20141006150324/http://www.soundtransit.org/Documents/pdf/projects/eastlink/factsheets/A_Sea_I90_110510.pdf |archive-date=October 6, 2014 |publisher=Sound Transit |access-date=September 30, 2014}}</ref><ref name="ST-2018Rainier">{{cite press release |date=September 17, 2018 |title=Rainier Freeway Station closing for East Link construction |url=https://www.soundtransit.org/get-to-know-us/news-events/news-releases/rainier-freeway-station-closing-east-link-construction |publisher=Sound Transit |access-date=December 7, 2018}}</ref>

==Service==
[[File:Metro bus and Link light rail passing at University Street Station (2010).jpg|thumb|right|A [[King County Metro]] bus and [[Sound Transit]] [[Link light rail]] train at [[Symphony station (Sound Transit)|Symphony station]], during joint bus–rail operations at tunnel stations|alt=A green bus pulling up to the curb of an underground station, pictured alongside a white train heading in the opposite direction]]

The Downtown Seattle Transit Tunnel is part of the "Third Avenue Transit Spine", the busiest transit corridor in Seattle, serving a combined average of 54,000 weekday riders with bus stops on the surface.<ref>{{cite web |year=2012 |title=Third Avenue Transit Corridor Improvement and RapidRide Facilities Project Description Information |url=http://www.psrc.org/assets/8022/King_County_Metro_-_Seattle_3rd_Ave_REVISED_-_Web.pdf |publisher=[[Puget Sound Regional Council]] |access-date=January 3, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150104071239/http://www.psrc.org/assets/8022/King_County_Metro_-_Seattle_3rd_Ave_REVISED_-_Web.pdf |archive-date=January 4, 2015 |df=mdy-all}}</ref> The tunnel has a theoretical capacity of 40 trains per hour per direction with a minimum of 90-second [[headway]]s, carrying 22,000 [[passengers per hour per direction]],<ref>{{cite tech report |date=December 2, 2004 |title=Regional Transit Long-Range Plan Draft Supplemental Environmental Impact Statement |chapter=Technical Appendix F: Capacity Calculations |url=http://www.soundtransit.org/documents/pdf/projects/seis/Appendix%20F%20-%20Capacity%20Calculations.pdf |format=PDF |page=F-3 |url-status=dead |archive-url=https://web.archive.org/web/20100616065323/http://soundtransit.org/documents/pdf/projects/seis/Appendix%20F%20-%20Capacity%20Calculations.pdf |archive-date=June 16, 2010 |institution=Sound Transit |access-date=September 30, 2014}}</ref> but is only able to carry 12,000 per hour per direction in 4-car light rail vehicles with current systems in place.<ref>{{cite news |last=Lindblom |first=Mike |date=December 4, 2015 |title=Would voters dig another transit tunnel? |url=http://www.seattletimes.com/seattle-news/transportation/sound-transit-may-propose-another-tunnel-in-27b-package/ |work=The Seattle Times |access-date=December 7, 2015 |url-status=live |archive-url=https://web.archive.org/web/20160122020817/http://www.seattletimes.com/seattle-news/transportation/sound-transit-may-propose-another-tunnel-in-27b-package/ |archive-date=January 22, 2016}}</ref> Prior to the start of Link light rail service, the DSTT could serve up to 145 buses during the afternoon [[rush hour]].<ref>{{cite report |date=March 2006 |title=North Link Final Supplemental Environmental Impact Statement |chapter=Chapter 3: Transportation Impacts and Mitigation |chapter-url=http://www.soundtransit.org/sites/default/files/documents/pdf/projects/link/nlinkseis_chapter3.pdf |publisher=Sound Transit |access-date=August 18, 2016 |archive-date=August 27, 2016 |archive-url=https://web.archive.org/web/20160827171342/http://www.soundtransit.org/sites/default/files/documents/pdf/projects/link/nlinkseis_chapter3.pdf |url-status=dead }}</ref> {{As of|2012}}, the DSTT carried 52,600 daily riders, of which 10,000 are on light rail<!--, with an annual total of X million passing through the five stations [annual ridership] -->.<ref>{{cite web |last=Limargo |first=Irin |date=August 1, 2012 |title=Operational Strategies to Prepare the Downtown Seattle Tunnel for Pay on Entry |url=http://www.apta.com/mc/multimodal/previous/2012/presentations/Presentations/Operational-Strategies-to-Prepare-the-Downtown-Seattle-Tunnel-for-Pay-on-Entry-Irin-Limargo.pdf |page=6 |publisher=[[American Public Transportation Association]] |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141006102854/http://www.apta.com/mc/multimodal/previous/2012/presentations/Presentations/Operational-Strategies-to-Prepare-the-Downtown-Seattle-Tunnel-for-Pay-on-Entry-Irin-Limargo.pdf |archive-date=October 6, 2014}}</ref>

The tunnel carries a segment of the 1&nbsp;Line, which runs for {{convert|33|mi|km}} from [[Lynnwood City Center station]] through the [[University of Washington]], [[Downtown Seattle]], and the [[Rainier Valley, Seattle|Rainier Valley]], and terminates at [[Angle Lake station]] near [[Seattle–Tacoma International Airport]].<ref>{{cite news |last1=Deshais |first1=Nicholas |last2=Lindblom |first2=Mike |date=August 30, 2024 |title=New Sound Transit light rail stations draw big crowds for first trips |url=https://www.seattletimes.com/seattle-news/transportation/new-light-rail-stations-draw-big-crowds-for-first-trips/ |work=The Seattle Times |accessdate=September 25, 2024}}</ref> Trains serve all downtown tunnel stations 20 hours a day every day; during regular weekday service, trains run roughly every six to 10 minutes during rush hour and midday operation, respectively, with longer headways of 15 minutes in the early morning and 20 minutes at night. During weekends, 1&nbsp;Line trains arrive every 10 minutes during midday hours and every 15 minutes during mornings and evenings. Light rail service from Westlake to International District/Chinatown takes approximately seven minutes.<ref name="LinkSchedule"/><ref name="KCM-Sept2015Change">{{cite press release |date=September 16, 2015 |title=Expanded Metro bus service coming; Link light rail ramps up in downtown tunnel |url=http://www.kingcounty.gov/elected/executive/constantine/news/release/2015/September/16-metro-service-change.aspx |publisher=King County Metro |access-date=December 7, 2015 |url-status=live |archive-url=https://web.archive.org/web/20151120191652/http://www.kingcounty.gov/elected/executive/constantine/News/release/2015/September/16-metro-service-change.aspx |archive-date=November 20, 2015}}</ref>

Prior to the cessation of bus service in March 2019, the DSTT was served by seven bus routes that stopped at all four tunnel stations as well as stops near the former [[Convention Place station]].<ref name="Times-CPS2018">{{cite news |last=Lindblom |first=Mike |date=July 20, 2018 |title=Downtown Seattle bus station closes for good Saturday. Here's where to find the buses |url=https://www.seattletimes.com/seattle-news/transportation/downtown-seattle-bus-station-closes-for-good-saturday-heres-where-to-find-the-buses/ |work=The Seattle Times |access-date=July 21, 2018}}</ref> At each station, bus routes were divided into three bays labeled with their general direction. Bay A was served by three routes heading north toward [[Northgate, Seattle|Northgate]] and the [[University District, Seattle|University District]] and east to [[Kirkland, Washington|Kirkland]] via [[Washington State Route 520|State Route 520]]; Bay C was served by three routes heading south through the SODO Busway toward the Rainier Valley and [[Renton, Washington|Renton]]; and Bay D was served by a single route, Sound Transit Express route 550, heading east to [[Mercer Island, Washington|Mercer Island]] and [[Bellevue, Washington|Bellevue]] via Interstate 90.<ref>{{cite web |date=March 2016 |title=Metro Transit Service Change: September 10, 2016 |url=http://metro.kingcounty.gov/up/sc/rideralert/2016/sept/revisions/list-view.html |publisher=King County Metro |access-date=September 11, 2016 |url-status=live |archive-url=https://web.archive.org/web/20160904091054/http://metro.kingcounty.gov/up/sc/rideralert/2016/sept/revisions/list-view.html |archive-date=September 4, 2016}}</ref><ref>{{cite map |publisher=King County Metro |date=June 2014 |title=Downtown Metro Service: Frequent Routes to Help You Get Around Downtown |url=http://metro.kingcounty.gov/maps/system/pdf/low-res/metro-system-map-downtown-seattle-low-res.pdf |format=PDF |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141006224832/http://metro.kingcounty.gov/maps/system/pdf/low-res/metro-system-map-downtown-seattle-low-res.pdf |archive-date=October 6, 2014}}</ref>

During closures of the Downtown Seattle Transit Tunnel, tunnel buses were rerouted onto 2nd and 4th Avenues between Yesler Way and Pine Street, and Stewart Street and Olive Way between 2nd and Boren Avenues. Metro also runs a [[Shuttle bus service|special route]], the [[List of King County Metro bus routes#Route 97|Route 97 Link Shuttle]], between all Link light rail stations during service disruptions.<ref>{{cite map |publisher=King County Metro |title=Surface Street Bus Stops When the Downtown Seattle Transit Tunnel is Closed |url=http://metro.kingcounty.gov/maps/pdf/downtown-seattle-tunnel-map-closed.pdf |format=PDF |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141007041905/http://metro.kingcounty.gov/maps/pdf/downtown-seattle-tunnel-map-closed.pdf |archive-date=October 7, 2014}}</ref>

==Operations==

The DSTT is open for 20 hours on weekdays and Saturdays, from 5:00&nbsp;am to 1:00&nbsp;am the following day, and for 18 hours on Sundays, from 6:00&nbsp;am to midnight.<ref name="Tunnel">{{cite web |title=Downtown Seattle Transit Tunnel |url=http://metro.kingcounty.gov/tops/tunnel/index.html |publisher=[[King County Metro]] |access-date=September 11, 2016 |url-status=live |archive-url=https://web.archive.org/web/20161016053308/http://metro.kingcounty.gov/tops/tunnel/index.html |archive-date=October 16, 2016}}</ref> At the time of its opening in 1990, the Metro Bus Tunnel only operated from 5:00&nbsp;am to 7:00&nbsp;pm on weekdays and 10:00&nbsp;am to 6:00&nbsp;pm on Saturdays, with no Sunday service;<ref name="SeaTimes-Opening">{{cite news |date=September 14, 1990 |title=Seattle Briefly: New bus schedules effective tomorrow |page=B3 |url=http://community.seattletimes.nwsource.com/archive/?date=19900914&slug=1093006 |work=The Seattle Times |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141006090546/http://community.seattletimes.nwsource.com/archive/?date=19900914&slug=1093006 |archive-date=October 6, 2014}}</ref> the operating hours were temporarily extended into weekday nights from 1998 to 2000 at the request of the [[Seattle Seahawks]] and [[Seattle Mariners]],<ref>{{cite news |last=Schaefer |first=David |date=May 29, 1998 |title=Bus-tunnel hours extended to 11 p.m. – fares to go up 15 cents a ride |page=B1 |work=The Seattle Times |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB539448B07F860?p=AMNEWS |url-access=subscription |via=NewsBank |access-date=September 30, 2014}}</ref> but were cut after the passage of [[List of Washington initiatives to the people#1999|Initiative 695]] and subsequent loss of motor vehicle [[excise tax]] revenue.<ref>{{cite news |last=Gilmore |first=Susan |date=June 2, 2002 |title=Bumper to Bumper: The story behind the gridlock |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=20020602&slug=bumper02m |work=The Seattle Times |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141006074607/http://community.seattletimes.nwsource.com/archive/?date=20020602&slug=bumper02m |archive-date=October 6, 2014}}</ref> Preparations for Link light rail service restored late-night and full weekend hours for the tunnel, introduced in June 2009 after Sound Transit Express route 550 moved all of its trips into the tunnel.<ref name="ST-550Move">{{cite press release |date=May 21, 2009 |title=New trains, new bus trips bring big changes in June |url=http://www.soundtransit.org/About-Sound-Transit/News-and-events/News-releases/News-release-archive/June-Service-Change-(2009) |location=Seattle, Washington |publisher=Sound Transit |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141006153822/http://www.soundtransit.org/About-Sound-Transit/News-and-events/News-releases/News-release-archive/June-Service-Change-%282009%29 |archive-date=October 6, 2014}}</ref>

Coordination between trains in the tunnel is managed by the Link Light Rail Operations Control Center (OCC), located at the King County Metro Communication and Control Center in [[SoDo, Seattle|SoDo]]. The OCC controls vehicle movements (and formerly operations between buses and trains) by using on-board [[radio-frequency identification]] tags installed on tunnel buses and light rail vehicles, their locations tracked by passing over [[induction loop]]s embedded in the tunnel roadway. Signals at each station indicate when a driver can proceed through the tunnel.<ref>{{cite report |date=July 29, 2008 |title=Central Link Operations Plan: Initial Segment and Airport Link |url=http://www.globaltelematics.com/pitf/SoundTransitCentralLinkOpsPlan.7.29.08.pdf |pages=26–28 |publisher=Sound Transit |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20150924022530/http://www.globaltelematics.com/pitf/SoundTransitCentralLinkOpsPlan.7.29.08.pdf |archive-date=September 24, 2015}}</ref> Within the DSTT, [[speed limit]]s are set at {{convert|15|mph|kph}} in stations and staging areas and {{convert|30|mph|kph}} between stations.<ref>{{cite web |editor-last=Eckhardt |editor-first=Katherine |date=June 7, 2011 |title=King County Metro Transit Operations Policies and Procedures #68: Downtown Seattle Transit Tunnel and SODO Busway Operations Procedure |url=http://www.atu587.org/sites/default/files/TO%20PoliciesProceduresManual%20rev%202013-10-07.pdf |publisher=[[Amalgamated Transit Union|Amalgamated Transit Union Local 587]] |access-date=September 30, 2014}}</ref><ref>{{cite web |date=March 31, 2018 |title=Rulebook for Link Light Rail |page=97 |url=https://kingcounty.gov/~/media/transportation/kcdot/MetroTransit/human-resources/rail-supervisor-training/2018-link-light-rail-rulebook.pdf |publisher=King County Metro |access-date=October 20, 2022 |archive-url=https://web.archive.org/web/20210909215357/https://kingcounty.gov/~/media/transportation/kcdot/MetroTransit/human-resources/rail-supervisor-training/2018-link-light-rail-rulebook.pdf |archive-date=September 9, 2021 |url-status=dead}}</ref> During joint operations, Light rail trains and buses were required to wait in the tunnels between stations until the platform was cleared of vehicles ahead;<ref>{{cite news |last=Lindblom |first=Mike |date=May 28, 2015 |title=State finally getting satellite-based train controls, 20 years after fatal crash |page=A1 |url=http://www.seattletimes.com/seattle-news/transportation/tracking-washington-states-train-safety/ |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202060906/http://www.seattletimes.com/seattle-news/transportation/tracking-washington-states-train-safety/ |archive-date=February 2, 2017}}</ref> buses were mandated to keep a minimum of six seconds of separation between each other.<ref name="TheBook"/>

During joint bus–rail operations, two types of vehicles were used in the Downtown Seattle Transit Tunnel: Sound Transit's [[Kinkisharyo-Mitsui]] light rail vehicles and King County Metro's [[New Flyer]] [[Diesel-electric transmission|diesel-electric]] [[hybrid electric bus|hybrid buses]].<ref>{{cite web |date=December 2006 |title=Link Light Rail Vehicle Statistics |url=http://www.soundtransit.org/Documents/pdf/projects/lightrail/central/CentralLinkVehicleSpecs.pdf |url-status=dead |archive-url=https://web.archive.org/web/20141006124139/http://www.soundtransit.org/Documents/pdf/projects/lightrail/central/CentralLinkVehicleSpecs.pdf |archive-date=October 6, 2014 |publisher=Sound Transit |access-date=September 30, 2014}}</ref> The New Flyer buses, dubbed "tunnel buses" by King County Metro, were ordered in 2004 to replace a fleet of [[Breda Costruzioni Ferroviarie|Breda]] [[dual-mode bus|dual-mode]] electric [[trolleybus]]es whose [[overhead wire]] was to be removed in the tunnel's renovation for light rail;<ref>{{cite web |title=New Flyer Articulated Low Floor Hybrid Bus |url=http://metro.kingcounty.gov/am/vehicles/hy-diesel.html |work=Metro Vehicles |publisher=King County Metro |access-date=August 16, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150704071416/http://metro.kingcounty.gov/am/vehicles/hy-diesel.html |archive-date=July 4, 2015}}</ref> 59 of the dual-mode Breda coaches were converted into fully electric trolleybuses between 2004 and 2007 and moved to surface routes,<ref name="Breda">{{cite web |title=Breda Articulated Trolley Bus |url=http://metro.kingcounty.gov/am/vehicles/breda-trolley.html |work=Metro Vehicles |publisher=King County Metro |access-date=September 30, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20141007004603/http://metro.kingcounty.gov/am/vehicles/breda-trolley.html |archive-date=October 7, 2014}}</ref><ref>{{cite press release |date=June 17, 2013 |title=Metro to partner with New Flyer on next generation of electric trolley buses |url=http://kingcounty.gov/depts/transportation/news-archive/archive/2013/20130617-trolley-contract.aspx |location=Seattle, Washington |publisher=King County Metro |access-date=March 27, 2015 |url-status=live |archive-url=https://web.archive.org/web/20170321170333/http://kingcounty.gov/depts/transportation/news-archive/archive/2013/20130617-trolley-contract.aspx |archive-date=March 21, 2017}}</ref> where they continued to operate for more than a decade before being fully replaced in 2016.<ref name="farewell-breda">{{cite web |last1=Gutierrez |first1=Scott |title=Farewell to Metro's Breda trolleys |publisher=King County Metro |date=October 28, 2016 |url=https://metrofutureblog.wordpress.com/2016/10/28/farewell-to-metros-breda-trolleys/ |access-date=May 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20161120064700/https://metrofutureblog.wordpress.com/2016/10/28/farewell-to-metros-breda-trolleys/ |archive-date=November 20, 2016}}</ref> The New Flyer [[low-floor bus|low-floor]], {{convert|61|ft|m|0|adj=mid|-long}} [[articulated bus]]es feature a "hush mode" that allowed buses to operate solely on stored electric power within the tunnel, minimizing emissions and noise.<ref>{{cite web |title=Downtown Seattle Transit Tunnel and Changing Bus Technology |url=http://metro.kingcounty.gov/am/vehicles/bustech.html |work=Metro Vehicles |publisher=King County Metro |access-date=September 30, 2014 |url-status=live |archive-url=https://web.archive.org/web/20141006163740/http://metro.kingcounty.gov/am/vehicles/bustech.html |archive-date=October 6, 2014}}</ref>

==History==

===Previous subway proposals===

Several proposals for a [[Cut-and-cover|cut-and-cover subway tunnel]] under 3rd Avenue in Downtown Seattle were presented to the City of Seattle by predecessors of the [[Seattle Planning Commission]] throughout the 20th century. The first major proposal was part of urban planner [[Virgil Bogue]]'s "Plan for Seattle" in 1911, as Route 1 of a proposed [[rapid transit]] network. Route 1 ran southeast on 3rd Avenue from a [[Orbital (metro)|circular ring]] around a proposed [[civic center]] in the [[Denny Regrade, Seattle|Denny Regrade]] neighborhood to [[King Street Station (Seattle)|King Street Station]], paralleled to the west by a subway on 1st Avenue known as Route 17; stations on the line were to have additional entrances from [[department store]]s and other major businesses on 3rd Avenue.<ref>{{cite book |last=Bogue |first=Virgil |author-link=Virgil Bogue |year=1911 |chapter=Appendix No. III—Proposed Rapid Transit System |title=Plan of Seattle: Report of the Municipal Plans Commission |location=Seattle, Washington |publisher=Lowman & Hanford |page=[https://archive.org/details/planseattlerepo00bogugoog/page/n219 180] |oclc=1440455 |url=https://archive.org/details/planseattlerepo00bogugoog |via=[[Internet Archive]] |access-date=August 16, 2015}}</ref><ref>{{cite news |date=November 12, 1911 |title=Municipal Plans Embrace Great Third Avenue Improvements |page=25 |work=The Seattle Times}}</ref> The plan was supported by City Engineer [[Reginald H. Thomson]] and the Municipal League among others, but opposed by businesses fearing it would shift the commercial district further north, and by the three daily newspapers published in Seattle. A special [[municipal election]] for the [[comprehensive plan]] was held on March 5, 1912, in which Seattle voters rejected it by a 10,000-vote margin.<ref>{{cite news |last=Crowley |first=Walt |date=September 17, 1972 |title=Virgil Bogue's plan: Seattle that might have been |pages=8–9 |work=The Seattle Times}}</ref><ref>{{cite news |date=March 6, 1912 |title=Single Tax And City Paper Are Voted Down: All Bond Issues Receive Approval of People and Voters Decide to Have a Look at Plans for Municipal Telephone System. |page=2 |work=The Seattle Times}}</ref>

Although Bogue's proposal was ultimately rejected, some elements of the plan were independently studied by others, including a rapid transit subway in Downtown Seattle. In 1920, City Engineer Arthur H. Dimmock published a report recommending a rapid transit system for the city of Seattle, centered around a cut-and-cover subway tunnel under 3rd Avenue from Virginia Street to Yesler Way. The line was to connect to surface and elevated lines at Dexter Avenue, Olive Way and South Jackson Street, serving the neighborhoods of [[Fremont, Seattle|Fremont]], [[Eastlake, Seattle|Eastlake]], [[Capitol Hill, Seattle|Capitol Hill]], and [[North Delridge, Seattle, Washington|North Delridge]] in [[West Seattle, Seattle|West Seattle]].<ref>{{cite book |last1=Dimmock |first1=Arthur H. |last2=Henderson |first2=D. W. |last3=Reeves |first3=Carl H. |date=December 16, 1920 |title=Report on Proposed Rapid Transit System for the City of Seattle |publisher=City of Seattle |oclc=46418921}}</ref><ref>{{cite web |date=June 2008 |title=2008 Find of the Month Archive: 1920 rapid transit plan |url=http://www.seattle.gov/cityarchives/exhibits-and-education/find-of-the-month/2008-find-of-the-month-archive#jun08 |publisher=Seattle Municipal Archives |access-date=August 16, 2015 |url-status=live |archive-url=https://web.archive.org/web/20150924095939/http://www.seattle.gov/cityarchives/exhibits-and-education/find-of-the-month/2008-find-of-the-month-archive |archive-date=September 24, 2015}}</ref> The proposal, which was expected not to be acted upon for at least 15 years, gained little support, and was called a project of "purely academic interest" by Mayor [[Hugh M. Caldwell]], who doubted that any rapid transit proposal would be seriously considered during his term.<ref>{{cite news |date=December 21, 1920 |title=Rapid Transit Sought; Plans Submitted to Members of City Council; Proposals for Seattle Would Cost Millions, Not Yet Officially Estimated |page=2 |work=The Seattle Daily Times}}</ref> The Seattle City Planning Commission proposed its own rapid transit system in 1926, centered on an elevated line over Western Avenue with a possible parallel subway under 3rd Avenue from Yesler Way to Pike Street.<ref>{{cite book |last=Trimble |first=William Pitt |year=1926 |title=Seattle Rapid Transit Report to the City Planning Commission |publisher=Seattle Planning Commission |oclc=14264109}}</ref> The Seattle Traffic Research Commission published a report in 1928 recommending a subway under 2nd Avenue from [[King Street Station]] to Pike Street as part of a longer rapid transit line serving the [[University District, Seattle|University District]] and Fremont.<ref>{{cite book |last1=Pollock |first1=C. D. |author2=Seattle Traffic Research Commission |author3=Clearing House Association of Seattle |date=December 1928 |title=Report of the Seattle Traffic Research Commission, 1928 |publisher=Seattle Traffic Research Commission |page=25 |oclc=11052336}}</ref> In the late 1950s, the Seattle Transit Commission proposed building a rapid transit system on the existing [[Right-of-way (transportation)|right-of-way]] used by [[Interstate 5 in Washington|Interstate 5]] between [[Tacoma, Washington|Tacoma]], Seattle and Everett, with a two-station subway under 5th Avenue in Downtown Seattle.<ref>{{cite book |last=Kennett |first=John J. |date=March 1, 1957 |title=Rapid Transit on Freeway, Tacoma-Seattle-Everett |publisher=Seattle Transit |oclc=13297486}}</ref>

The most significant rapid transit proposal came as part of the [[Forward Thrust]] initiatives of the late 1960s, which was centered around a downtown subway under 3rd Avenue. The subway would be fed by lines from [[Ballard, Seattle|Ballard]], [[Lake City, Seattle|Lake City]], the University District, Capitol Hill, [[Bellevue, Washington|Bellevue]], and [[Renton, Washington|Renton]], combining for a planned minimum headway of {{nowrap|1.5}} minutes at rush hour, {{nowrap|2.5}} minutes during midday, and five minutes at all other times.<ref>{{cite map |author=De Leuw, Cather & Company |date=March 19, 1970 |title=The Rapid Transit Plan for the Metropolitan Seattle Area: Technical Appendix |map=Figure 7-2: Rapid Transit Average Travel Times and Assumed Headways |map-url=https://www.flickr.com/photos/sounderbruce/16827879379 |via=Flickr |page=7{{hyphen}}33 |publisher=Municipality of Metropolitan Seattle |oclc=36627361}}</ref> The stations on 3rd Avenue were to be situated at South Jackson Street and 5th Avenue South, James and Cherry streets, Seneca and Spring streets, and Pike and Pine streets, all planned to open by 1985 and operated by the [[Municipality of Metropolitan Seattle]].<ref>{{cite book |author=De Leuw, Cather & Company |date=February 19, 1970 |title=The Rapid Transit Plan for the Metropolitan Seattle Area |chapter=Chapter 1: Recommended Public Transportation Plan |page=15 |publisher=Municipality of Metropolitan Seattle |oclc=120953}}</ref> Seattle voters were asked to provide $385 million (equivalent to ${{Format price|{{Inflation|US|385000000|1968}}}} in {{Inflation-year|US}} dollars),{{inflation-fn|US}} to supplement a $765 million grant (equivalent to ${{Format price|{{Inflation|US|765000000|1968}}}} in {{Inflation-year|US}} dollars){{inflation-fn|US}} from the [[Urban Mass Transportation Administration]] (UMTA), during a municipal election on February 13, 1968, narrowly passing the [[Municipal bond|bond]] by 50.8%, but falling short of the required 60 percent [[supermajority]].<ref>{{cite web |last=McRoberts |first=Patrick |date=January 1, 1999 |title=King County voters on Forward Thrust bonds approve stadium and aquarium and nix transit on February 13, 1968. |url=http://www.historylink.org/File/2168 |work=HistoryLink |access-date=August 16, 2015 |url-status=live |archive-url=https://web.archive.org/web/20161002015123/http://www.historylink.org/File/2168 |archive-date=October 2, 2016}}</ref> A second attempt on May 19, 1970, with an adjusted $440 million local contribution (equivalent to ${{Format price|{{Inflation|US|440000000|1970}}}} in {{Inflation-year|US}} dollars){{inflation-fn|US}} and $881 million federal grant (equivalent to ${{Format price|{{Inflation|US|881000000|1970}}}} in {{Inflation-year|US}} dollars),{{inflation-fn|US}} failed to pass with only 46% approval amid a local [[Recession of 1969–70|recession]] caused by layoffs at [[Boeing]]; the [[earmark (politics)|earmarked]] funds intended for the Forward Thrust rapid transit project were instead allocated to [[Atlanta]], to build its [[MARTA|rapid transit system]].<ref>{{cite web |date=September 19, 2002 |title=Voters reject rail transit plan and three other Forward Thrust bond proposals on May 19, 1970. |url=http://www.historylink.org/File/3961 |work=HistoryLink |access-date=August 16, 2015 |url-status=live |archive-url=https://web.archive.org/web/20161002030443/http://www.historylink.org/File/3961 |archive-date=October 2, 2016}}</ref>

===Bus tunnel proposal and approval===

The concept of a downtown bus tunnel was first proposed in 1974 during discussions between [[Governor of Washington|Governor]] [[Daniel J. Evans|Dan Evans]] and [[Mayor of Seattle|Seattle Mayor]] [[Wesley C. Uhlman|Wes Uhlman]] about regional transportation projects in response to the proposed extension of Interstate 90 into Seattle via a [[Homer M. Hadley Memorial Bridge|third floating bridge]] crossing [[Lake Washington]].<ref>{{cite news |last=Lane |first=Bob |date=December 19, 1974 |title=Downtown bus tunnel, third bridge in Evans-Uhlman plan |page=A1 |work=The Seattle Times}}</ref> [[Municipality of Metropolitan Seattle|Metro Transit]] later commissioned a study into the bus tunnel,<ref>{{cite news |date=December 22, 1974 |title=Metro Transit planning firm is hired |page=A11 |work=The Seattle Times}}</ref> released the following July, which determined that it would not be able to adequately meet the rush hour demand of downtown bus ridership by 1980. The study suggested that a double-decked tunnel with [[automated guideway transit]] to complement bus service, running from Union Station to the [[Seattle Center]], would be able to meet projected demand at an estimated cost of $450 million.<ref>{{cite news |date=July 25, 1975 |title=Study weighs solutions to busways jam |page=A6 |work=The Seattle Times}}</ref> Ultimately, the plan was rejected because of the high cost of ventilation for diesel buses that would use the tunnel.<ref name="1979proposal">{{cite news |last=Lane |first=Bob |date=July 29, 1979 |title=Metro takes new look at bus tunnel |page=A22 |work=The Seattle Times}}</ref> The bus tunnel proposal resurfaced in 1979, outlining a tunnel from South Jackson Street to Pine Street that would carry 200 buses an hour in each direction at a cost of up to $350 million with the option of conversion for electric rail transit in the future. The tunnel was suggested by Metro officials and engineering consultants [[Parsons Brinckerhoff]] as a solution to worsening downtown traffic, and was better received than alternative concepts.<ref name="1979proposal"/> The proposal gained further support from Metro Transit in its long-term "Metro 1990" plan, adopted in 1981, as a transit mall or tunnel under 3rd Avenue carrying buses that could be converted for a light rail system. The [[Puget Sound Council of Governments]] (PSCOG), a regional planning agency, endorsed Metro Transit's proposal and integrated the tunnel into its proposed light rail line connecting Seattle to [[Snohomish County, Washington|Snohomish County]].<ref>{{cite news |last=Lane |first=Bob |date=March 22, 1981 |title='Light rail' system might solve transit problems, says study |page=A16 |work=The Seattle Times}}</ref><ref>{{cite news |last=Gough |first=William |date=December 5, 1982 |title=Rapid-transit system studied for Seattle, Snohomish County |page=B31 |work=The Seattle Times}}</ref>

The Metro Transit Committee debated the inclusion of the bus tunnel in the project's [[environmental impact assessment]] well into 1983, Seattle members opposing the tunnel in favor of a transit mall and suburban members supporting a bus tunnel that would be converted to a light rail system.<ref>{{cite news |last=Gough |first=William |date=June 3, 1983 |title=Bus-tunnel proposal debated by Metro committee |page=B6 |work=The Seattle Times}}</ref><ref>{{cite news |last=Gough |first=William |date=June 10, 1983 |title=Debate on tunnel vs. transit mall continues |page=B2 |work=The Seattle Times}}</ref> On September 22, UMTA requested that a preferred alternative be declared by the end of November, which prompted the Metro Council to expedite its decision. Metro Council Executive Director Neil Peterson favored the tunnel alternative, while the [[Seattle City Council]] and Mayor [[Charles Royer]] preferred the transit mall, but stated that a tunnel would be a long-term solution to downtown congestion.<ref>{{cite news |last=Gough |first=William |date=October 3, 1983 |title=Metro chief urges a city tunnel for electric buses |page=B1 |work=The Seattle Times}}</ref> The Seattle City Council reversed its decision on their preferred alternative, voting unanimously on October 17 in favor of an electric-only transit tunnel. Along with Mayor Royer, they were willing to compromise on Peterson's proposed dual-mode buses to serve suburban commuters where trolleybuses were not feasible.<ref>{{cite news |last=Schaefer |first=David |date=October 18, 1983 |title=City Council would approve electric buses in downtown tunnel |page=B1 |work=The Seattle Times}}</ref> The Metro Council approved the downtown bus tunnel by a unanimous vote on November 3, 1983, estimating a cost of $300 million to build a five-station tunnel under 3rd Avenue and Pine Street to be completed in 1989 along with the conversion of 3rd Avenue into a landscaped transit mall.<ref>{{cite news |last=Gough |first=William |date=November 4, 1983 |title=Metro Council OK's downtown transit tunnel |page=B1 |work=The Seattle Times}}</ref>

===Planning, funding and design===

Metro unveiled its preliminary plans for the bus tunnel in January 1984, selecting five sites for stations along 3rd Avenue and Pine Street: at Union Station, the King County Courthouse, between Seneca and Union streets, at the Westlake Mall, and near the Washington State Convention Center. The [[Burlington Northern Railroad]] opposed Metro's preference for the tunnel to cross the existing [[Great Northern Tunnel]] by going under it, the agency stating that passing over would require a [[cut-and-cover tunnel]] that would disrupt [[City Hall Park (Seattle)|City Hall Park]].<ref name="SeaTimes-84Stations">{{cite news |last1=Nogaki |first1=Sylvia |last2=Gough |first2=William |date=January 14, 1984 |title=Metro chooses bus-station sites, hits snag over downtown tunnel |page=A8 |work=The Seattle Times}}</ref> The following month, Metro announced that it would use a fleet of 200 dual-mode buses for the first decade of tunnel operations, with an eventual switch to subway trains. The [[bored tunnel]] would be able to carry 180 buses an hour in each direction, serving either a wide [[island platform]] or two smaller [[side platform]]s that would be dug out from the surface.<ref>{{cite news |last=Gough |first=William |date=January 26, 1984 |title=Bus tunnel, transit plan would cost $400 million |page=C1 |work=The Seattle Times}}</ref><ref>{{cite news |last=Nogaki |first=Sylvia |date=February 18, 1984 |title=Metro envisions city bus subway in 5 years |page=A6 |work=The Seattle Times}}</ref> In April, Metro published the draft [[environmental impact statement]] for the tunnel project, estimating a cost of $387 million (equivalent to ${{inflation|US|387|1984|r=0}}&nbsp;million in {{Inflation-year|US}} dollars){{inflation-fn|US}} and a completion date of June 1989.<ref>{{cite news |last=Parker |first=Laura |date=April 15, 1984 |title=Underground: Metro wants bus tunnel |pages=A26–A27 |work=[[Seattle Post-Intelligencer]], The Seattle Times}}</ref> The cost of the project drew criticism at [[public hearing]]s for using a significant portion of Metro's capital budget, a total of $840 million from sales tax revenue approved by voters in 1980, as well as potential disruption to business during the cut-and-cover construction of the stations and Pine Street segment of the tunnel.<ref>{{cite news |last=Nogaki |first=Sylvia |date=April 24, 1984 |title=Hearing to study downtown bus tunnel |page=B1 |work=The Seattle Times}}</ref><ref>{{cite news |last=Nogaki |first=Sylvia |date=April 26, 1984 |title=Metro's plan for buses draws fire |page=B1 |work=The Seattle Times}}</ref>

UMTA ranked Metro's bus tunnel project as first among transit projects favored to receive federal funding in 1985, despite its reliance on unproven dual-mode buses. Metro tested a prototype [[Renault]] PER 180 dual-mode trolleybus in 1983, describing it as problematic after finding it exceeded freeway [[axle load]] limits by {{convert|2|ST|MT|lk=on}} and having to replace several parts after several mechanical failures.<ref>{{cite news |last=Nogaki |first=Sylvia |date=May 18, 1984 |title=Metro project gets edge for federal funding |pages=A1, A12 |work=The Seattle Times}}</ref> [[98th United States Congress|Congress]] later appropriated $20 million to the City of Seattle for the bus tunnel project in October 1984, allowing for right-of-way acquisition to begin,<ref>{{cite news |date=October 12, 1984 |title=Seattle wins $20 million for building downtown bus tunnel |page=B5 |agency=[[United Press International]] |work=The Seattle Times}}</ref> but the funds were withheld until restrictions on new transit projects were lifted by the [[United States Senate]] the following May.<ref>{{cite news |last=Anderson |first=Ross |date=May 15, 1985 |title=Federal funds to be freed for bus tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5313FB2B165F0?p=AMNEWS |url-access=subscription |via=NewsBank |page=A1 |work=The Seattle Times |access-date=August 16, 2015}}</ref>

The Downtown Transit Project subcommittee unanimously approved Metro recommendations that would reduce the number of bus tunnel stations from six to five, saving $35 million, as well as opting for [[tunnel boring machine]]s for the 3rd Avenue segment to minimize surface-level disruptions that would be present from cut-and-cover excavation.<ref>{{cite news |last=Nogaki |first=Sylvia |date=September 13, 1984 |title=Panel urges boring of Metro tunnel — and 5 stations |page=B2 |work=The Seattle Times}}</ref> Stations would be located at Union Station south of Jackson Street, under 3rd Avenue and James Street, under 3rd Avenue and University Street, at the [[Westlake Mall]] and at 9th Avenue and Pine Street near the Washington State Convention Center.<ref>{{cite news |date=November 1, 1984 |title=Panel picks sites for tunnel stations |page=C6 |work=The Seattle Times}}</ref> The Metro Council approved the station sites and use of tunnel-boring machines in July 1985, proceeding with final design by approving a $25.9 million contract with Parsons Brinckerhoff for engineering work related to the project.<ref>{{cite news |date=July 19, 1985 |title=Metro OK's contract for design for bus tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB53158221CEDC8?p=AMNEWS |url-access=subscription |via=NewsBank |page=B5 |work=The Seattle Times |access-date=August 16, 2015}}</ref><ref>{{cite news |last=Lane |first=Bob |date=August 30, 1985 |title=Metro driving forward with tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5316A0086C871?p=AMNEWS |url-access=subscription |via=NewsBank |page=B2 |work=The Seattle Times |access-date=August 16, 2015}}</ref>

In March 1986, the federal government offered Metro a contract committing $195 million in UMTA funding toward the bus tunnel, requiring that a decision on whether to move forward with the project be made by December 31.<ref>{{cite news |last=Lane |first=Bob |date=March 21, 1986 |title=Metro ironing out bus-tunnel contract |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB531C37AF35C73?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> A month later, the [[King County Council]] asked Metro to consider delaying construction of the bus tunnel while waiting for assurance on federal funding being able to cover half of the $395 million cost of the project; the council was scheduled to begin awarding contracts for utility relocation along 3rd Avenue and Pine Street in preparation for tunnel construction.<ref>{{cite news |last=Lane |first=Bob |date=April 3, 1986 |title=Metro asked to study bus-tunnel delay |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB531C7E970582D?p=AMNEWS |url-access=subscription |via=NewsBank |page=D1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> On May 15, the [[Presidency of Ronald Reagan|Reagan administration]] signed a contract with Metro to commit $197 million of the $395 million required for the bus tunnel project, assuming re-authorization of a mass transit grant program by Congress, while also extending the deadline for a final decision to September 1987.<ref>{{cite news |last=Pryne |first=Eric |date=May 15, 1986 |title=Administration gives Metro 'full-funding' contract for bus tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB531D59127C7EE?p=AMNEWS |url-access=subscription |via=NewsBank |page=A9 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Hours later, the Metro Council awarded the first construction contract for utility relocation, with construction set to begin in July.<ref>{{cite news |last=Lane |first=Bob |date=May 16, 1986 |title=Metro awards bus-tunnel contract – go-ahead given after U.S. agrees to assist |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB531D60665117D?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> The Metro Council accepted the UMTA contract during their June 5 meeting, allowing for bidding on tunnel construction to begin.<ref>{{cite news |last=Gilmore |first=Susan |date=June 6, 1986 |title=$23.6 million freed for transit tunnel – 'full-funding contract' OK'd |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB531DE3333AD1E?p=AMNEWS |url-access=subscription |via=NewsBank |page=B4 |work=The Seattle Times |access-date=August 16, 2015}}</ref> The tunnel construction contract was awarded to the [[joint venture]] of Guy F. Atkinson Construction and [[Dillingham Construction]] in late September for $44.16 million, beating seven competing bids with an estimate far lower than the approximately $61 million predicted by Metro engineers.<ref>{{cite news |date=September 19, 1986 |title=Around the Sound: First contract given for Metro's bus tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5320124931358?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=August 16, 2015}}</ref><ref>{{cite news |date=September 12, 1986 |title=Bus-tunnel bid so low that engineers gasp |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB531FF34757E4C?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> The contract for the dual-mode trolleybuses was awarded by the Metro Council to [[Breda Costruzioni Ferroviarie]] in October, consisting of an order for 236 buses at a cost of $133 million (equivalent to ${{inflation|US|133|1986|r=0}}&nbsp;million in {{Inflation-year|US}} dollars);{{inflation-fn|US}}<ref>{{cite news |last=Lane |first=Bob |date=October 25, 1986 |title=Italian company submits low bid to build 236 Metro 'tunnel buses' |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5320E226D0D2B?p=AMNEWS |url-access=subscription |via=NewsBank |page=D8 |work=The Seattle Times |access-date=August 16, 2015}}</ref> it was approved by UMTA in November.<ref>{{cite news |last=Lane |first=Bob |date=November 3, 1986 |title=Metro gets OK to buy Italian-made buses |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532115CE2D225?p=AMNEWS |url-access=subscription |via=NewsBank |page=B12 |work=The Seattle Times |access-date=August 16, 2015}}</ref>

===Construction===
[[File:Breda dual-mode bus at Westlake station in Downtown Seattle Transit Tunnel, 9-17-1990.jpg|thumb|left|A [[dual-mode bus]] at [[Westlake station (Sound Transit)|Westlake station]] in 1990, operating as an electric [[trolleybus]] while in the tunnel|alt=A white bus with raised poles stopped at the curb of an underground station. The granite-tiled floors reflect bright lanterns placed above the platform, adjacent to an upper level walkway.]]

Construction on the bus tunnel project began with partial closures of 3rd Avenue in July 1986 for utility relocation, narrowing traffic to one lane in either direction and restricting traffic to buses and emergency vehicles during rush hour.<ref>{{cite news |last=Gilje |first=Shelby |date=July 11, 1986 |title=Third Avenue work disrupts mail |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB531EA83C76EAB?p=AMNEWS |url-access=subscription |via=NewsBank |page=E5 |work=The Seattle Times |access-date=August 16, 2015}}</ref> To prepare for extended periods of service disruption on 3rd Avenue, Metro Transit also moved its [[Trolleybuses in Seattle|electric trolleybus routes]] onto 1st Avenue.<ref>{{cite news |last=Updike |first=Robin |date=January 27, 1987 |title=Downtown merchants move, add promotion tax in their efforts to survive city's new construction |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB53233503C451E?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=August 16, 2015}}</ref>

Excavation of the 3rd Avenue tunnel segment began with the ceremonial launch of the "Mighty Mole", a {{convert|140|ST|MT|adj=mid}}, {{convert|129|ft|m|adj=mid|-long}} [[tunnel boring machine]] (TBM), on March 6, 1987.<ref name="HL-031987"/><ref>{{cite news |last=Lane |first=Bob |date=March 2, 1987 |title='Mighty Mole' is a giant pest – Metro Tunnel is headache for merchants 
|url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5323E0220A8C8?p=AMNEWS |url-access=subscription |via=NewsBank |page=B1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> The TBM, designed by Robbins Company of [[Kent, Washington]], and built by Nicholson Manufacturing in Seattle, began digging the western tunnel from Union Station the following May.<ref>{{cite news |last=Lane |first=Bob |date=May 15, 1987 |title=Big 'Mole' to gnaw through downtown – exotic white machine displayed, christened |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532560068CCF7?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> A second, identical "Mighty Mole" TBM began digging the parallel eastern tunnel on June 29.<ref>{{cite news |last=Lane |first=Bob |date=June 26, 1987 |title='Mole' is burrowing bus tunnel – 140-ton 'creature' digging its way under downtown |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB53263015D790F?p=AMNEWS |url-access=subscription |via=NewsBank |page=A1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> During tunnel boring under 3rd Avenue between Spring Street and [[Madison Street (Seattle)|Madison Street]] on October 21, a small [[earthflow]] damaged a [[water main]] and caused pavement on 3rd Avenue to drop {{convert|8|in|cm}}, shutting down water in the nearby [[Seattle City Light]] and [[1001 Fourth Avenue Plaza]] buildings.<ref>{{cite news |last=Blater |first=Joni |date=October 21, 1987 |title=Water taps run dry on Third Avenue |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532890052CC9A?p=AMNEWS |url-access=subscription |via=NewsBank |page=D1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> While repairing the broken water main, electricians working on damaged [[high-voltage cable]]s caused a small [[power outage]] that affected eight downtown buildings on the night of October 28, but were able to restore power by the following morning.<ref>{{cite news |date=October 27, 1987 |title=Seattle Briefly: Power restored to 8 downtown buildings |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5328B59F891C9?p=AMNEWS |url-access=subscription |via=NewsBank |page=D1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Work on the western tunnel was briefly interrupted in November, when the TBM hit an unexpectedly large pocket of loose sand under Madison Street that had to be stabilized with [[grout]] to prevent damage to the adjacent Seattle City Light building.<ref>{{cite news |last=Lane |first=Bob |date=November 6, 1987 |title=Loose sand delays work on bus tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5328EB524A1B4?p=AMNEWS |url-access=subscription |via=NewsBank |page=B2 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Boring on both tunnels was stopped in early January 1988, when a pocket of wet sand was encountered {{convert|300|ft|m}} before the planned 90-degree turn onto Pine Street.<ref>{{cite news |last=Lane |first=Bob |date=January 20, 1988 |title=Ice Age sand trap halts machine age bus-tunnel project |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532AFE32F86C4?p=AMNEWS |url-access=subscription |via=NewsBank |page=A1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Metro and tunnel contractors [[Guy F. Atkinson Construction|Atkinson]]/Dillingham, who had scheduled tunnel excavation for completion in mid-January, closed 3rd Avenue between Pike and Pine streets and installed 40 [[water well|drilled wells]] to remove water from the sand pocket in February.<ref>{{cite news |last=Lane |first=Bob |date=January 23, 1988 |title=Extraction of water may delay bus tunnel digging 6–8 weeks |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532B08923279F?p=AMNEWS |url-access=subscription |via=NewsBank |page=A8 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Digging resumed on the western tunnel on March 14,<ref>{{cite news |last=Lott |first=Jimi |date=March 14, 1988 |title=Looking over the down under |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532C148B921D1?p=AMNEWS |url-access=subscription |via=NewsBank |page=B1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> and the TBM reached Westlake station on April 9, completing the first of the two tunnels.<ref>{{cite news |date=April 9, 1988 |title=One bus-tunnel tube excavated |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532C95C7B5884?p=AMNEWS |url-access=subscription |via=NewsBank |page=C16 |work=The Seattle Times |access-date=August 16, 2015}}</ref> The eastern tunnel was completed a month later on May 18, allowing for parts of the TBMs to be salvaged and the steel outer shells to be buried in the tunnel.<ref>{{cite news |last=Lane |first=Bob |date=May 18, 1988 |title=Light at the end of Metro's tunnel – breakthrough day downtown for Seattle's Mighty Mole |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532D78CDE5240?p=AMNEWS |url-access=subscription |via=NewsBank |page=D1 |work=The Seattle Times |access-date=August 16, 2015}}</ref>

The Pine Street segment of the tunnel was planned to be dug cut-and-cover from the surface. In preparation for utility relocation work on Pine Street, Metro moved 36 bus routes serving the corridor to other east–west streets in February 1987.<ref>{{cite news |last=Lane |first=Bob |date=February 3, 1987 |title=Big dig will close Pine St. to buses |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532352ED6B77F?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> On April 27, excavation of the tunnel began with the closure of Pine Street, and its offramp to Interstate 5, to automobile traffic between 3rd Avenue and Boren Avenue.<ref>{{cite news |last=Lane |first=Bob |date=April 25, 1987 |title=Pine Street in downtown area to be off limits to most traffic – tunnel construction forces closure for at least a year |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5324F1DFBC946?p=AMNEWS |url-access=subscription |via=NewsBank |page=A8 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Workers finished digging in late August, allowing the project to progress to concrete pouring for the roadway.<ref>{{cite news |last=Lane |first=Bob |date=August 25, 1987 |title=Pouring begins: Thick concrete for tunnel beneath Pine Street |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5327539175ACE?p=AMNEWS |url-access=subscription |via=NewsBank |page=C3 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Pine Street was briefly re-opened for the [[Christmas shopping|Christmas shopping season]] beginning November 1 at the request of downtown merchants, with a temporary surface laid over [[backfill]] for automobiles and pedestrians.<ref>{{cite news |last=Lane |first=Bob |date=November 2, 1987 |title=Pine St. reopens – for the shoppers |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5328D0E84BBD8?p=AMNEWS |url-access=subscription |via=NewsBank |page=B3 |work=The Seattle Times |access-date=August 16, 2015}}</ref> On January 4, the street was closed to automobile traffic once again, along with the intersection of 5th Avenue and Pine Street and the Pike Street offramp of I-5, to install utility lines and a permanent roadway.<ref>{{cite news |last=Lane |first=Bob |date=December 31, 1987 |title=Jackhammers will take over Pine Street again |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532A180E589A0?p=AMNEWS |url-access=subscription |via=NewsBank |page=E3 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Pine Street was fully reopened to traffic on November 1, 1988, coinciding with the completion of [[Westlake Park (Seattle)|Westlake Park]] and the Westlake Center shopping mall, a year ahead of schedule.<ref>{{cite news |date=November 1, 1988 |title=Northwest Briefly: Ramp, Street opening to help speed traffic |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB533126647F272?p=AMNEWS |url-access=subscription |via=NewsBank |page=B2 |work=The Seattle Times |access-date=August 16, 2015}}</ref>

By October 1988, Metro reported that 53% of major construction was complete and anticipated that the tunnel would be completed in May 1990 and opened for service in September 1990.<ref>{{cite news |last=Lane |first=Bob |date=October 8, 1988 |title=Tunnel job going out of sight – 'Sidewalk superintendents' losing view |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB533095565A228?p=AMNEWS |url-access=subscription |via=NewsBank |page=A1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Seattle Mayor [[Norm Rice]] and City Council members [[Paul Kraabel]] and George Benson recommended a limited opening of the tunnel for the [[1990 Goodwill Games]] to be held in July,<ref>{{cite news|last=Lane |first=Bob |date=January 21, 1990 |title=Safety officials oppose opening tunnel for games |page=B9 |url=http://community.seattletimes.nwsource.com/archive/?date=19900121&slug=1051925 |work=The Seattle Times |access-date=August 16, 2015 |url-status=live |archive-url=https://web.archive.org/web/20160304063246/http://community.seattletimes.nwsource.com/archive/?date=19900121&slug=1051925 |archive-date=March 4, 2016}}</ref> but Metro rejected the proposal so that the safety systems of the tunnel could be tested adequately before service began.<ref>{{cite news|date=February 15, 1990 |title=Games here too soon for tunnel, says staff |page=D4 |url=http://community.seattletimes.nwsource.com/archive/?date=19900215&slug=1056312 |work=The Seattle Times |access-date=August 16, 2015 |url-status=live |archive-url=https://web.archive.org/web/20160304055838/http://community.seattletimes.nwsource.com/archive/?date=19900215&slug=1056312 |archive-date=March 4, 2016}}</ref> Testing in the bus tunnel began with a ceremonial first run on March 15, 1989, first with a diesel bus and then one of the Breda dual-mode trolleybuses operating in diesel mode, as the overhead trolley wires had not yet been installed.<ref name="FirstRun">{{cite news |last=Lane |first=Bob |date=March 16, 1989 |title=First run: Buses roll through the tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5334D1754FBFD?p=AMNEWS |url-access=subscription |via=NewsBank |page=A1 |work=The Seattle Times}}</ref><ref name="FastenSeatBelts">{{cite news |last=Bailey |first=Gil |date=March 17, 1989 |title=Fasten your seat belts ... Metro bus takes the press on a bumpy ride through the tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB0491A6ABD2900?p=AMNEWS |url-access=subscription |via=NewsBank |page=B3 |work=Seattle Post-Intelligencer}}</ref> Wooden planks and steel plates covered slots in the concrete roadway where rails would be installed later.<ref name="FirstRun"/><ref name="FastenSeatBelts"/> Local media were given a tour the next day.<ref name="FastenSeatBelts"/> By January 1990, the tunnel stations were declared "nearly complete",  with only minor work still left for contractors.<ref>{{cite news|date=January 2, 1990 |title=End is near for work on city's bus tunnel |page=B3 |url=http://community.seattletimes.nwsource.com/archive/?date=19900102&slug=1048744 |work=The Seattle Times |access-date=August 16, 2015 |url-status=live |archive-url=https://web.archive.org/web/20160304072913/http://community.seattletimes.nwsource.com/archive/?date=19900102&slug=1048744 |archive-date=March 4, 2016}}</ref> Murals and other interactive art installations were placed in the nearly complete stations from December 1989 onward, as part of a $1.5 million arts program.<ref>{{cite news |last=Lane |first=Bob |date=December 21, 1989 |title=Art Tunnel: Metro installs murals, fancy fixtures to make bus stations a visual treat |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB533B9F81FEFCA?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=August 16, 2015}}</ref> Tunnel construction was finished on June 7, 1990, leaving Metro to test safety systems and train personnel for regular service to begin in September.<ref name="Silence90">{{cite news|last=Lane |first=Bob |date=June 7, 1990 |title=Deafening silence: Bus tunnel's done |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=19900607&slug=1075987 |work=The Seattle Times |access-date=August 16, 2015 |url-status=live |archive-url=https://web.archive.org/web/20160303224319/http://community.seattletimes.nwsource.com/archive/?date=19900607&slug=1075987 |archive-date=March 3, 2016}}</ref>

The initial cost of the tunnel project was estimated in 1984 to be $334.6 million, but the final costs rose 56% over budget to a total of $468.7 million (equivalent to ${{Format price|{{Inflation|US|468700000|1990}}}} in {{Inflation-year|US}} dollars);{{inflation-fn|US}}<ref>{{cite report |author=Office of Planning and Environment |date=September 2007 |title=Contractor Performance Assessment Report |chapter=Appendix 1: Project Profiles |page=156 |chapter-url=http://www.fta.dot.gov/documents/CPAR_Final_Report_-_2007.pdf |url-status=dead |archive-url=https://web.archive.org/web/20160304112736/http://www.fta.dot.gov/documents/CPAR_Final_Report_-_2007.pdf |archive-date=March 4, 2016 |publisher=[[Federal Transit Administration]] |access-date=August 16, 2015}}</ref><ref>{{cite news|last=Gutierrez |first=Scott |date=October 17, 2009 |title=Report: Other Seattle-area tunnels have been over-budget |url=http://blog.seattlepi.com/transportation/2009/10/17/report-other-seattle-area-tunnels-have-been-over-budget/ |work=Seattle Post-Intelligencer |access-date=August 16, 2015 |url-status=live |archive-url=https://web.archive.org/web/20150612151240/http://blog.seattlepi.com/transportation/2009/10/17/report-other-seattle-area-tunnels-have-been-over-budget/ |archive-date=June 12, 2015}}</ref> the project's cost overruns were blamed on unanticipated soil conditions on the approach to Pine Street from 3rd Avenue, complaints and payouts to downtown businesses disrupted by tunnel construction, and the death of an electrician during construction.<ref name="HL-031987"/> Excavated dirt from the project was used as fill for runway expansion at [[Paine Field]] in nearby [[Everett, Washington|Everett]].<ref>{{cite news |last=Bergsman |first=Jerry |date=March 22, 1989 |title=Here's inside dirt on dealings between Metro and Paine Field |page=H2 |work=The Seattle Times}}</ref>

====South African granite scandal====

A minor scandal involving the bus tunnel project emerged in late 1988, over the discovery that granite to be used by Metro in the tunnel's stations had been sourced from [[South Africa]]. The Verde Fontaine granite was quarried in South Africa, which had been under [[Apartheid|Apartheid rule]] at the time, but was cut and finished in Italy, allowing for it to be approved despite the Metro Council's ongoing [[Disinvestment from South Africa|boycott of South African goods]].<ref>{{cite web |last=Crowley |first=Walt |date=January 1, 2000 |title=Metro Director Alan Gibbs resigns on February 23, 1989, in scandal over use of South African granite in bus tunnel. |url=http://www.historylink.org/File/2022 |work=HistoryLink |access-date=July 20, 2016 |url-status=live |archive-url=https://web.archive.org/web/20161019081535/http://www.historylink.org/File/2022 |archive-date=October 19, 2016}}</ref><ref>{{cite book |first=David B. |last=Williams |author-link=David Williams (author) |title=The Seattle Street-Smart Naturalist: Field Notes from the City |publisher=Westwinds Press |year=2000 |isbn=9781558688599 |oclc=277040822 |url=https://books.google.com/books?id=drbCCQAAQBAJ |via=Google Books |access-date=July 15, 2017}}</ref> The Verde Fontaine granite was selected for use as benches and interior walls in Westlake and Pioneer Square stations by architecture firm TRA; Metro was unaware that Verde Fontaine was only quarried in South Africa. The granite's origin was discovered by an activist from the Black Contractors Coalition in late 1988, who notified Metro and members of the Metro Council. Metro determined that replacing the {{convert|24,000|sqft|sqm}} of granite would cost $500,000 and delay both stations but would not delay the planned 1990 opening and would be covered by contingency funds in the project's budget.<ref>{{cite news |last1=Lane |first1=Bob |last2=Pryne |first2=Eric |date=January 6, 1989 |title=South African stone blocks bus tunnel – Metro rejection means $500,000 increase in cost, delay in completing two stations |page=B1 |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB533349325426F?p=AMNEWS |url-access=subscription |via=NewsBank |work=The Seattle Times |access-date=July 20, 2016}}</ref>

During a press conference on January 25, 1989, Metro Director Alan Gibbs confirmed that the granite had been quarried in South Africa and announced that an investigative report would be delivered to the Metro Council Transit Committee the following week.<ref>{{cite news |last=Lane |first=Bob |date=January 25, 1989 |title=S. African granite flap: Metro's story – Gibbs concedes error in buying stone but says public wasn't misled |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5333BCAD5A5F6?p=AMNEWS |url-access=subscription |via=NewsBank |page=B2 |work=The Seattle Times |access-date=July 20, 2016}}</ref> The announcement was met with calls from King County Councilman [[Ron Sims]] to fire the responsible Metro officials who knowingly allowed the purchase.<ref>{{cite news |last=Pryne |first=Eric |date=January 27, 1989 |title=Firings sought over purchase from S. Africa – Sims demands Metro tell who OK'd using the granite in new bus tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5333C5AB5AE27?p=AMNEWS |url-access=subscription |via=NewsBank |page=E1 |work=The Seattle Times |access-date=July 20, 2016}}</ref> Metro's ban on South African goods was stricter than the federal sanctions, which only prohibited importation of specific materials such as steel, coal, uranium and agricultural products, and was used by UMTA to threaten to pull its funding for the bus tunnel project.<ref>{{cite news |last=Pryne |first=Eric |date=February 7, 1989 |title=Agency may force Metro to keep granite – No decision made yet on S. African stone |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB533400A33B46E?p=AMNEWS |url-access=subscription |via=NewsBank |page=B1 |work=The Seattle Times |access-date=July 20, 2016}}</ref>

A report by the Metro Council Rules Committee delivered in March stated that the granite's origin was discovered in early 1988, and was authorized by tunnel superintendent David Kalberer with the assumption that only a small amount would be used to furnish [[University Street station]] (now Symphony station).<ref name="Times-Cover">{{cite news |last=Lane |first=Bob |date=March 10, 1989 |title=Report to Metro finds no cover-up on granite – Committee tries to heal wounds over South African stone in tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5334AF3244E26?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=July 20, 2016}}</ref> Kalberer, who received praise for his work on the project before the scandal, admitted that the failure to consult the Metro Council's tunnel subcommittee before signing off on the deal was his mistake.<ref name="Times-Kalberer">{{cite news |last=Lane |first=Bob |date=February 26, 1989 |title=The man who OK'd S. African granite – Kalberer got high marks for bus tunnel project before ugly episode |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5334646E67434?p=AMNEWS |url-access=subscription |via=NewsBank |page=D1 |work=The Seattle Times |access-date=July 20, 2016}}</ref> Metro Director Alan Gibbs resigned on February 23 as a result of the scandal and was succeeded by technical director Richard Sandaas in September.<ref>{{cite news |last1=Pryne |first1=Eric |last2=Lane |first2=Bob |date=February 23, 1989 |title=Metro chief Gibbs resigns – S. African granite dispute is cause |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB533452A1F5A2B?p=AMNEWS |url-access=subscription |via=NewsBank |page=A1 |work=The Seattle Times |access-date=July 20, 2016}}</ref><ref>{{cite news |last=Lane |first=Bob |date=September 8, 1989 |title=Sandaas named to head Metro |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5338FA58156B6?p=AMNEWS |url-access=subscription |via=NewsBank |page=C4 |work=The Seattle Times |access-date=July 20, 2016}}</ref> The granite was rejected by Metro and was returned to the supplier in Italy.<ref name="Times-Cover"/><ref name="Times-Kalberer"/>

Before this discovery, in September 1987, African-American rights groups had forced tunnel contractor Atkinson/Dillingham to return 36 steel beams from South Africa used for temporary [[shoring]] at [[Pioneer Square station]]. This led Metro Director Alan Gibbs to propose a ban on South African materials by Metro for its projects, which was adopted by a resolution of the Metro Council on September 17.<ref>{{cite news |last=Lane |first=Bob |date=September 4, 1987 |title=Metro bans South African steel from bus-tunnel project – complaints from officials, black groups |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5327903B172EE?p=AMNEWS |url-access=subscription |via=NewsBank |page=B2 |work=The Seattle Times |access-date=July 20, 2016}}</ref><ref>{{cite news |last=Pryne |first=Eric |date=February 2, 1989 |title=Metro staff put loophole into ban – Council unaware of flaw in action on South Africa |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5333E66E5C221?p=AMNEWS |url-access=subscription |via=NewsBank |page=C1 |work=The Seattle Times |access-date=July 20, 2016}}</ref>

===Opening and bus-only operation===

Regular service in the bus tunnel began on September 15, 1990, on five routes serving the University District, North Seattle, and Renton.<ref name="HL-Opening"/><ref name="SeaTimes-Opening"/> The limited service was the result of delays in the manufacturing of dual-mode buses from Breda, which were fully delivered in 1991.<ref>{{cite news |last=Winfield |first=Phyllis |date=September 16, 1990 |title=It's tunnel time: Bus riders check it out |page=B2 |url=http://community.seattletimes.nwsource.com/archive/?date=19900916&slug=1093322 |work=The Seattle Times |access-date=January 22, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081659/http://community.seattletimes.nwsource.com/archive/?date=19900916&slug=1093322 |archive-date=February 2, 2017}}</ref><ref>{{cite news |last=Lane |first=Bob |date=September 11, 1990 |title=The Metro Mission: Easy riders |page=A4 |work=The Seattle Times}}</ref> The opening was preceded by [[soft opening]]s of each individual station, beginning with Westlake station in August 1989, and ending with Convention Place station the day before the beginning of service.<ref>{{cite news |last=Lane |first=Bob |date=August 12, 1989 |title=Tunnel station opens to raves |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB5338264CC0E28?p=AMNEWS |url-access=subscription |via=NewsBank |page=A11 |work=The Seattle Times |access-date=January 22, 2017}}</ref><ref>{{cite news |last=Macdonald |first=Patrick |date=September 14, 1990 |title=Bochinche goes underground for Metro bus tunnel |page=8 |url=http://community.seattletimes.nwsource.com/archive/?date=19900914&slug=1093113 |work=The Seattle Times |access-date=January 22, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081657/http://community.seattletimes.nwsource.com/archive/?date=19900914&slug=1093113 |archive-date=February 2, 2017}}</ref> A ceremonial [[walkathon|walk and run]] was held on September 9, 1990, and attracted 5,000 participants.<ref>{{cite news |last=Smith |first=Craig |date=August 31, 1990 |title=Runners with tunnel vision can check out Metro route |page=D7 |url=http://community.seattletimes.nwsource.com/archive/?date=19900831&slug=1090609 |work=The Seattle Times |access-date=January 22, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081707/http://community.seattletimes.nwsource.com/archive/?date=19900831&slug=1090609 |archive-date=February 2, 2017}}</ref><ref>{{cite news |last=Gillman |first=Joel |date=September 10, 1990 |title=After 411-miler, runner wins short one in tunnel |page=C7 |url=http://community.seattletimes.nwsource.com/archive/?date=19900910&slug=1092351 |work=The Seattle Times |url-status=live |archive-url=https://web.archive.org/web/20170202081701/http://community.seattletimes.nwsource.com/archive/?date=19900910&slug=1092351 |archive-date=February 2, 2017}}</ref>

In its first year of operations, the bus tunnel carried 28,000 daily passengers on 688 scheduled bus trips. The tunnel reduced the number of buses operated on 3rd Avenue at peak hours from 190 to 86, with 20 Metro routes using the tunnel.<ref>{{cite news |last=Lane |first=Bob |date=September 16, 1991 |title=Bus tunnel rolls into second year–despite problems, downtown project is proving to be an underground hit |url=http://community.seattletimes.nwsource.com/archive/?date=19910916&slug=1305738 |page=B1 |work=The Seattle Times |access-date=January 22, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081703/http://community.seattletimes.nwsource.com/archive/?date=19910916&slug=1305738 |archive-date=February 2, 2017}}</ref> ''[[The Seattle Times]]'' called it a "qualified success", commenting that the tunnel was like a "mini-subway system". The paper's editorial board also requested that Metro expand tunnel hours to keep buses running for late-night workers and entertainment events held on weekends.<ref>{{cite news |author=Seattle Times editorial board |date=September 17, 1991 |title=Happy anniversary: Tunnel can work harder |page=A10 |work=The Seattle Times}}</ref> On December 9, 1991, the [[SODO Busway]] opened, extending bus service from the tunnel into SODO and moving southbound routes off Interstate 5.<ref>{{cite news |last=Lane |first=Bob |date=December 7, 1991 |title=New busway to help south end commuters |page=A10 |url=http://community.seattletimes.nwsource.com/archive/?date=19911207&slug=1321554 |work=The Seattle Times |access-date=January 22, 2017 |url-status=live |archive-url=https://web.archive.org/web/20161128135048/http://community.seattletimes.nwsource.com/archive/?date=19911207&slug=1321554 |archive-date=November 28, 2016}}</ref> Direct access from [[Interstate 90 (Washington)|Interstate 90]] to the bus tunnel was opened in February 1992 as part of a reversible express lane system for the [[Homer M. Hadley Memorial Bridge|new floating bridge]].<ref>{{cite news |last=Johnston |first=Steve |date=February 17, 1992 |title=Reversible car-pool lane debuts on I-90 |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=19920217&slug=1476235 |work=The Seattle Times |access-date=January 22, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081705/http://community.seattletimes.nwsource.com/archive/?date=19920217&slug=1476235 |archive-date=February 2, 2017}}</ref>

The first use of the tunnel by Sound Transit buses began on September 18, 1999, with the takeover of Metro's Seattle–Bellevue express route, which was renumbered from 226 to 550.<ref name="TM-230">{{cite magazine |title=Trolleynews [regular news section] |date=March–April 2000 |magazine=Trolleybus Magazine |volume=36 |issue=230 |publisher=National Trolleybus Association |location=UK |page=47 |issn=0266-7452 |oclc=62554332}}</ref><ref>{{cite news |last=Whitely |first=Peyton |date=September 17, 1999 |title=Buses ready to roll |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=19990917&slug=2983670 |work=The Seattle Times |access-date=May 4, 2018 |url-status=live |archive-url=https://web.archive.org/web/20160304050713/http://community.seattletimes.nwsource.com/archive/?date=19990917&slug=2983670 |archive-date=March 4, 2016 |df=mdy-all}}</ref> To operate buses in the tunnel, Sound Transit leased 20 dual-mode buses from Metro, repainted them in the agency's colors, and contracted with Metro to operate the route along with other Sound Transit Express routes in King County.<ref name="TM-230"/><ref>{{cite web |date=August 19, 1999 |title=Sound Transit Motion No. M99-55 |url=https://www.soundtransit.org/sites/default/files/documents/pdf/about/board/motions/1999/motion20no20m99-55.pdf |publisher=Sound Transit |access-date=May 4, 2018 |archive-url=https://web.archive.org/web/20180505135246/https://www.soundtransit.org/sites/default/files/documents/pdf/about/board/motions/1999/motion20no20m99-55.pdf |archive-date=May 5, 2018 |url-status=dead |df=mdy-all}}</ref><ref>{{cite web |date=August 26, 1999 |title=Sound Transit Resolution No. R99-30 |url=https://www.soundtransit.org/sites/default/files/documents/pdf/about/board/resolutions/1999/reso20r99-30.pdf |publisher=Sound Transit |access-date=May 4, 2018 |archive-url=https://web.archive.org/web/20180505135420/https://www.soundtransit.org/sites/default/files/documents/pdf/about/board/resolutions/1999/reso20r99-30.pdf |archive-date=May 5, 2018 |url-status=dead |df=mdy-all}}</ref>

===Renovation for light rail===
[[File:Conventionplacestation3.JPG|thumb|right|Aerial view of [[Convention Place station]], the former northern terminus of the tunnel and the only station not served by Link light rail trains|alt=A parking lot filled with buses, seen from above. A station with several blue-roofed platforms can be seen towards the bottom, with lanes for buses and tracks for trains.]]

From the outset, the bus tunnel was intended to be converted for [[light rail]] trains at some point in the future.<ref>{{cite news |last=Lane |first=Bob |date=March 18, 1988 |title=Metro staff to advocate rails in tunnel |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532C29D695921?p=AMNEWS |url-access=subscription |via=NewsBank |page=E3 |work=The Seattle Times |access-date=January 23, 2017}}</ref> Metro approved the addition of tracks to the bus tunnel in 1988, appropriating half of the $5 million used to install them during tunnel construction, the remainder coming from federal sources.<ref>{{cite news |last=Lane |first=Bob |date=April 22, 1988 |title=Metro makes tracks for tracks for future |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532CDFAF32FA8?p=AMNEWS |url-access=subscription |via=NewsBank |page=B1 |work=The Seattle Times |access-date=January 23, 2017}}</ref><ref>{{cite news |last=Pryne |first=Eric |date=May 25, 1988 |title=Panel OK's $1 million for bus-tunnel rails |url=http://infoweb.newsbank.com/resources/doc/nb/news/0EB532DA14B9142C?p=AMNEWS |url-access=subscription |via=NewsBank |page=D2 |work=The Seattle Times |access-date=January 23, 2017}}</ref> To save $1.5 million in costs, Metro eliminated most of the rail's [[Insulator (electricity)|electrical insulation]], which would later render them unusable for rail service.<ref name="Pryne2005">{{cite news |last=Pryne |first=Eric |date=October 13, 2005 |title=Bus-tunnel error years ago is costly in shutdown today |url=http://old.seattletimes.com/html/localnews/2002557741_tunnel13m.html |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202051148/http://old.seattletimes.com/html/localnews/2002557741_tunnel13m.html |archive-date=February 2, 2017}}</ref>

A regional transit authority was formed in the early 1990s to build and operate a light rail system that would use the bus tunnel within Downtown Seattle. The authority, later named [[Sound Transit]], gained voter approval in November 1996 to build a $3.9&nbsp;billion system between Seattle–Tacoma International Airport, Downtown Seattle, and the University District.<ref>{{cite news |last=Schaefer |first=David |date=November 6, 1996 |title=Voters back transit plan on fourth try |page=A1 |url=http://community.seattletimes.nwsource.com/archive/?date=19961106&slug=2358535 |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20160303215211/http://community.seattletimes.nwsource.com/archive/?date=19961106&slug=2358535 |archive-date=March 3, 2016}}</ref> In 1998, Sound Transit found that the rails in the tunnel would need to be replaced at a cost of up to $110 million and require a full closure for two years. The plan would also require the purchase of new [[hybrid electric bus]]es to replace the Breda fleet, as the electrical systems were incompatible. Convention Place station would have to be abandoned as it was too shallow to support a northern extension under Interstate 5.<ref>{{cite news |last=Varner |first=Lynne K. |date=September 25, 1998 |title=Plan to convert tunnel for trains wins support |page=B3 |url=http://community.seattletimes.nwsource.com/archive/?date=19980925&slug=2774043 |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081656/http://community.seattletimes.nwsource.com/archive/?date=19980925&slug=2774043 |archive-date=February 2, 2017}}</ref><ref>{{cite news |last=Schaefer |first=David |date=September 29, 1998 |title=Light-rail chief says new track in tunnel won't break budget |page=B1 |work=The Seattle Times}}</ref>

Sound Transit approved its route for the light rail project, named [[Central Link]] (now the 1&nbsp;Line), in November 1999, including four of the five stations in the downtown transit tunnel (excluding Convention Place).<ref>{{cite news |last=Fryer |first=Alex |date=November 19, 1999 |title=A milestone for light rail: regional board selects station sites, alignment |page=A1 |url=http://community.seattletimes.nwsource.com/archive/?date=19991119&slug=2996198 |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20151222114849/http://community.seattletimes.nwsource.com/archive/?date=19991119&slug=2996198 |archive-date=December 22, 2015}}</ref> [[King County Executive]] Ron Sims proposed transferring ownership of the tunnel, along with $130 million in debt and liabilities for maintenance and operations, from King County Metro to Sound Transit in 2004.<ref>{{cite news |date=November 11, 1999 |title=Sims' light in the tunnel |page=B6 |work=The Seattle Times}}</ref> The two agencies signed an agreement in May 2000 that formally transferred ownership and responsibility for the tunnel to Sound Transit, in exchange for $195.6 million paid to King County Metro. Metro would retain ownership of Convention Place station and other assets, while Sound Transit would convert the tunnel to rail operation after 2004.<ref>{{cite news |last=Garber |first=Andrew |date=April 26, 2000 |title=Sound Transit set to acquire bus tunnel |page=B1 |work=The Seattle Times}}</ref><ref>{{cite news |date=May 23, 2000 |title=Transfer of tunnel to Sound Transit approved |page=B3 |url=http://community.seattletimes.nwsource.com/archive/?date=20000523&slug=4022693 |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081732/http://community.seattletimes.nwsource.com/archive/?date=20000523&slug=4022693 |archive-date=February 2, 2017}}</ref>

Sound Transit underwent a funding crisis in 2001 after the Central Link light rail project was found to be over budget and would not be able to open until 2009, three years later than planned.<ref>{{cite news |date=December 13, 2000 |title=Light-rail cost soars $1 billion |page=A1 |url=http://community.seattletimes.nwsource.com/archive/?date=20001213&slug=TTGI2KF2J |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20160114231022/http://community.seattletimes.nwsource.com/archive/?date=20001213&slug=TTGI2KF2J |archive-date=January 14, 2016}}</ref> The light rail project was truncated to Westlake station in Downtown Seattle and to [[Tukwila, Washington|Tukwila]], the sections north of downtown and south to the airport being deferred to a later date.<ref>{{cite news |last=Pryne |first=Eric |date=November 30, 2001 |title=Sound Transit adopts 14-mile route; light-rail construction could start in summer |page=A1 |url=http://community.seattletimes.nwsource.com/archive/?date=20011130&slug=sound30m0 |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170106174621/http://community.seattletimes.nwsource.com/archive/?date=20011130&slug=sound30m0 |archive-date=January 6, 2017}}</ref> The King County Council called for a new agreement to be negotiated with Sound Transit adding requirements for an adopted plan for light rail service to [[Northgate station (Sound Transit)|Northgate]], and for a study into new riders that light rail would bring to the tunnel over a conventional bus network.<ref>{{cite news |last=Pryne |first=Eric |date=September 25, 2001 |title=Bus-tunnel transfer to face a new curve |page=B3 |work=The Seattle Times}}</ref> In early 2002, Sound Transit also explored, and ultimately rejected, a proposal to build a parallel, rail-only tunnel under 5th Avenue that would cost $1 billion.<ref>{{cite news |last=Pryne |first=Eric |date=May 16, 2002 |title=Separate transit tunnel could cost $1 billion |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=20020516&slug=tunnel16m |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081712/http://community.seattletimes.nwsource.com/archive/?date=20020516&slug=tunnel16m |archive-date=February 2, 2017}}</ref>

Sound Transit and the King County Council signed a new joint-operations agreement in June 2002, leaving King County Metro as owners of the tunnel and Sound Transit responsible for paying part of the tunnel's debt service at an estimated cost of $65 million. The agreement would allow for buses and light rail trains to share the tunnel and its stations beginning in 2009, after a two-year closure for renovations.<ref>{{cite news |last=Pryne |first=Eric |date=June 25, 2002 |title=Sound Transit, county agree to bus-tunnel plan |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=20020625&slug=tunnel25m |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081729/http://community.seattletimes.nwsource.com/archive/?date=20020625&slug=tunnel25m |archive-date=February 2, 2017}}</ref><ref>{{cite news |last=Pryne |first=Eric |date=May 12, 2002 |title=The bus tunnel tug-of-war |page=A1 |url=http://community.seattletimes.nwsource.com/archive/?date=20020512&slug=tunnel12m0 |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081716/http://community.seattletimes.nwsource.com/archive/?date=20020512&slug=tunnel12m0 |archive-date=February 2, 2017}}</ref> A separate agreement signed in May 2003 selected King County Metro as the operator of the light rail line.<ref>{{cite press release |date=May 12, 2003 |title=Sound Transit reaches proposed agreement for Metro to operate Central Link light rail |url=http://www.soundtransit.org/About-Sound-Transit/News-and-events/News-releases/News-release-archive/Sound-Transit-reaches-proposed-agreement-for-Metro-to-operate-Central-Link-light-rail |publisher=Sound Transit |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202032006/http://www.soundtransit.org/About-Sound-Transit/News-and-events/News-releases/News-release-archive/Sound-Transit-reaches-proposed-agreement-for-Metro-to-operate-Central-Link-light-rail |archive-date=February 2, 2017}}</ref>

Metro began testing a fleet of new hybrid diesel-electric buses in 2002, intending to use them in the bus tunnel before and after the conversion to joint bus-rail operations.<ref>{{cite news |last=Lindblom |first=Mike |date=February 2, 2003 |title=Metro impressed by hybrid buses |page=B1 |work=The Seattle Times}}</ref> The first few of a planned fleet of 235 hybrid diesel-electric [[articulated bus]]es began operating on tunnel bus routes in June 2004.<ref>{{cite news |last=Lindblom |first=Mike |date=May 28, 2004 |title=Metro to roll out hybrid buses June 5 |page=B3 |url=http://old.seattletimes.com/html/localnews/2001941025_hybrid28m.html |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20160721051553/http://old.seattletimes.com/html/localnews/2001941025_hybrid28m.html |archive-date=July 21, 2016}}</ref> The Breda dual-mode trolleybuses were removed from the tunnel in January 2005 and would later be refurbished into electric-only trolleybuses for use on the city's trolleybus network.<ref name="Breda"/> The last day of trolleybus operation in the tunnel was January 24, 2005, with only a single dual-mode bus in service on the final day.<ref name="TM-261">{{cite magazine |title=Trolleynews [regular news section] |date=May–June 2005 |magazine=Trolleybus Magazine |volume=41 |issue=261 |publisher=National Trolleybus Association |location=UK |page=72 |issn=0266-7452 |oclc=62554332}}</ref><ref>{{cite web |title=Retired – Breda 5000 dual mode bus |url=http://metro.kingcounty.gov/am/vehicles/retired/breda.html |publisher=King County Metro |access-date=July 15, 2017 |archive-date=May 28, 2010 |archive-url=https://web.archive.org/web/20100528061807/http://metro.kingcounty.gov/am/vehicles/retired/breda.html |url-status=dead }}</ref>

In February 2004, Sound Transit announced that it would begin the closure and renovation of the bus tunnel in September 2005, two years earlier than scheduled, to save money and reduce construction delays.<ref>{{cite news |last=Pryne |first=Eric |date=February 13, 2004 |title=Downtown bus tunnel to close in '05, ahead of plan |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=20040213&slug=bustunnel13m |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081737/http://community.seattletimes.nwsource.com/archive/?date=20040213&slug=bustunnel13m |archive-date=February 2, 2017}}</ref> Construction of a stub tunnel under Pine Street near Convention Place station, to be used for light rail train storage and turnback, as well as a future extension to Capitol Hill, began in January 2005.<ref>{{cite news |last=Pryne |first=Eric |date=January 6, 2005 |title=Digging is 1st sign light rail coming to town |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=20050106&slug=downtownrail06m |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081715/http://community.seattletimes.nwsource.com/archive/?date=20050106&slug=downtownrail06m |archive-date=February 2, 2017}}</ref> The bus tunnel was closed on September 24, 2005, moving the tunnel's 21 routes and 140 buses per hour to surface streets.<ref name="FAQ2005">{{cite news |date=September 23, 2005 |title=Whats, whys of $82.7 million tunnel project |page=A15 |url=http://old.seattletimes.com/html/localnews/2002514380_bustunnelqampa23m.html |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202055718/http://old.seattletimes.com/html/localnews/2002514380_bustunnelqampa23m.html |archive-date=February 2, 2017}}</ref> 3rd Avenue was converted to a "transit-priority corridor" during peak periods, restricting general traffic to one-block travel.<ref>{{cite news |last=Gilmore |first=Susan |date=September 23, 2005 |title=Bus tunnel shuts down tonight for 2 years |page=A1 |url=http://old.seattletimes.com/html/localnews/2002514381_bustunnel23m.html |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202060355/http://old.seattletimes.com/html/localnews/2002514381_bustunnel23m.html |archive-date=February 2, 2017}}</ref>

The $82.7 million construction contract for the transit tunnel renovation was awarded to [[Balfour Beatty]] in August 2004, 12 percent below Sound Transit's estimates.<ref>{{cite web |date=August 12, 2004 |title=Sound Transit Motion No. M2004-78 |url=http://www.soundtransit.org/sites/default/files/documents/pdf/about/board/motions/2004/m2004-78.pdf |publisher=Sound Transit |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202031953/http://www.soundtransit.org/sites/default/files/documents/pdf/about/board/motions/2004/m2004-78.pdf |archive-date=February 2, 2017}}</ref><ref>{{cite news |last=Pryne |first=Eric |date=June 26, 2004 |title=Sound Transit bid comes in 12% lower than estimate |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=20040626&slug=soundtransit26m |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081757/http://community.seattletimes.nwsource.com/archive/?date=20040626&slug=soundtransit26m |archive-date=February 2, 2017}}</ref> The majority of the cost was paid by Sound Transit and supplemented by $8.1 million from King County Metro.<ref name="FAQ2005"/> As part of the renovations, the tunnel's roadway was lowered by {{convert|8|in|cm|spell=in}} to allow for level boarding, required by the [[Americans with Disabilities Act]]; as a result, Metro added [[strobe light]]s to bus mirrors, which were lowered to head height, and added warning signs. New electrical, mechanical, and emergency systems were installed, along with a new communications system connecting to a joint-operations center.<ref name="Pryne2005"/> The project ended up costing $94 million in total, 3.4 percent over the budget set in 2004.<ref>{{cite news |last1=Gilmore |first1=Susan |last2=Lindblom |first2=Mike |date=September 18, 2007 |title=Seattle gets a glimpse of its transit future |page=A1 |url=http://community.seattletimes.nwsource.com/archive/?date=20070918&slug=tunnel18m |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081755/http://community.seattletimes.nwsource.com/archive/?date=20070918&slug=tunnel18m |archive-date=February 2, 2017}}</ref> During the closure, Metro found that average travel time through downtown increased only 11 percent during the afternoon peak period, and ridership on popular routes only dropped slightly.<ref>{{cite news |last=Gilmore |first=Susan |date=March 11, 2006 |title=Metro delays shorter than feared |page=B1 |url=http://community.seattletimes.nwsource.com/archive/?date=20060311&slug=tunnel10m |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081759/http://community.seattletimes.nwsource.com/archive/?date=20060311&slug=tunnel10m |archive-date=February 2, 2017}}</ref>

===Joint bus and train operations===

The tunnel reopened to service on September 24, 2007, with tunnel routes modified to group common destinations together.<ref>{{cite news |last=Gilmore |first=Susan |date=September 24, 2007 |title=Reopening of downtown Seattle bus tunnel goes smoothly |url=http://old.seattletimes.com/html/localnews/2003899601_webbustunnel24m.html |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202060937/http://old.seattletimes.com/html/localnews/2003899601_webbustunnel24m.html |archive-date=February 2, 2017}}</ref><ref>{{cite news |last=Brown |first=Charles E. |date=September 17, 2007 |title=Bumper to Bumper: Tunnel outcasts want in |url=http://old.seattletimes.com/html/localnews/2003888225_bumper17m.html |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202060828/http://old.seattletimes.com/html/localnews/2003888225_bumper17m.html |archive-date=February 2, 2017}}</ref> Initially, the reopened tunnel was in use only on weekdays, with Saturday operation not yet reinstated.<ref>{{cite web |date=September 2007 |title=Rider Alert September 2007: Downtown Seattle Transit Tunnel Summary of Changes |url=http://metro.kingcounty.gov/up/sc/rideralert/ra-092007-t-summary.html |publisher=King County Metro |access-date=May 4, 2018 |url-status=live |archive-url=https://web.archive.org/web/20180504105149/http://metro.kingcounty.gov/up/sc/rideralert/ra-092007-t-summary.html |archive-date=May 4, 2018}}</ref> Stations were given new entrance signs, lighting fixtures, electronic [[passenger information system|passenger information signs]], and restored paint.<ref>{{cite web |title=What's new in the tunnel? |url=http://www.seattletunnel.org/whatsnew.asp |url-status=dead |work=SeattleTunnel.org |archive-url=https://web.archive.org/web/20071217032946/http://www.seattletunnel.org/whatsnew.asp |archive-date=December 17, 2007 |access-date=January 23, 2017}}</ref> The peak bus-only restrictions on 3rd Avenue remained in place after the reopening, along with the [[skip-stop]] service that Metro implemented on the street.<ref>{{cite news |last=Gilmore |first=Susan |date=July 28, 2007 |title=Third Ave. to keep its rush-hour restrictions |page=B2 |url=http://community.seattletimes.nwsource.com/archive/?date=20070728&slug=buses28m |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202081805/http://community.seattletimes.nwsource.com/archive/?date=20070728&slug=buses28m |archive-date=February 2, 2017}}</ref> The tunnel was temporarily closed for nine days in December after a computer glitch disrupted the tunnel's new emergency-control system, which was repaired and replaced.<ref>{{cite news |date=December 27, 2007 |title=Local Digest: Bus service resumes in downtown tunnel |url=http://old.seattletimes.com/html/localnews/2004093945_dige27m.html |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202060720/http://old.seattletimes.com/html/localnews/2004093945_dige27m.html |archive-date=February 2, 2017}}</ref> The tunnel had remained closed on weekends after its reopening,<ref>{{cite web |title=Downtown Seattle Transit Tunnel |url=http://metro.kingcounty.gov:80/tops/tunnel/tunnel.html |publisher=King County Metro |access-date=May 4, 2018 |url-status=live |archive-url=https://web.archive.org/web/20090522014655/http://metro.kingcounty.gov/tops/tunnel/tunnel.html |archive-date=May 22, 2009 |df=mdy-all}}</ref> but Saturday operation was reinstated and Sunday operation was introduced in May 2009.<ref>{{cite news |last=Cohen |first=Aubrey |date=May 20, 2009 |title=Light-rail trains start simulated service beside buses in transit tunnel |url=https://www.seattlepi.com/local/transportation/article/Light-rail-trains-start-simulated-service-beside-1304063.php |work=Seattle Post-Intelligencer |access-date=May 4, 2018}}</ref><ref>{{cite web |title=Bus Service Revisions Begin Saturday, May 30, 2009 [section: New Hours for the Downtown Seattle Transit Tunnel] |url=http://metro.kingcounty.gov:80/up/sc/rideralert/ra-052009.html |date=May 20, 2009 |publisher=King County Metro |access-date=May 4, 2018 |url-status=live |archive-url=https://web.archive.org/web/20090526204359/http://metro.kingcounty.gov/up/sc/rideralert/ra-052009.html |archive-date=May 26, 2009 |df=mdy-all}}</ref>

Simulated light rail testing in the tunnel also began on May 20, 2009, with two-car trains operating alongside in-service buses, making it the first joint bus and rail tunnel with stations in the United States; the [[Mount Washington Transit Tunnel]], a joint bus and rail tunnel in [[Pittsburgh, Pennsylvania]], had already been in operation but lacked underground stations.<ref>{{cite news |last=Lindblom |first=Mike |date=May 21, 2009 |title=Tunnel two-step: It may take buses longer to clear shared tunnel |page=A1 |url=http://old.seattletimes.com/html/localnews/2009245024_stdowntown21m0.html |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202060754/http://old.seattletimes.com/html/localnews/2009245024_stdowntown21m0.html |archive-date=February 2, 2017}}</ref> Service on the Central Link light rail line began on July 18, 2009, operating from Westlake station in the tunnel to [[Tukwila International Boulevard station]] near the airport.<ref>{{cite press release |date=July 18, 2009 |title=Link light rail launches new era of mobility for central Puget Sound |url=http://www.soundtransit.org/About-Sound-Transit/News-and-events/News-releases/News-release-archive/LinkInService |location=Seattle, Washington |publisher=Sound Transit |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20160303225339/http://www.soundtransit.org/About-Sound-Transit/News-and-events/News-releases/News-release-archive/LinkInService |archive-date=March 3, 2016}}</ref><ref>{{cite news |last=Lindblom |first=Mike |date=July 20, 2009 |title=Light-rail trains run smoothly, if not to capacity, on first day |url=http://old.seattletimes.com/html/localnews/2009503977_websoundtransit20m.html |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20161128135143/http://old.seattletimes.com/html/localnews/2009503977_websoundtransit20m.html |archive-date=November 28, 2016}}</ref> Light rail service was extended north from Westlake to University of Washington station (via [[Capitol Hill station]]) on March 19, 2016,<ref>{{cite news |last=Beekman |first=Daniel |date=March 19, 2016 |title=Capitol Hill, UW light-rail stations open to big crowds |url=http://www.seattletimes.com/seattle-news/transportation/capitol-hill-uw-light-rail-stations-open/ |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170101203045/http://www.seattletimes.com/seattle-news/transportation/capitol-hill-uw-light-rail-stations-open/ |archive-date=January 1, 2017}}</ref> coinciding with the moving of several bus routes out of the tunnel to accommodate increased train frequencies.<ref>{{cite press release |date=March 6, 2015 |title=Linked up: Transit agencies working together on bus changes as Link expands to Husky Stadium |url=http://kingcounty.gov/elected/executive/constantine/news/release/2015/March/03-transit-service-coordination.aspx |location=Seattle, Washington |publisher=King County Metro |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202013159/http://kingcounty.gov/elected/executive/constantine/news/release/2015/March/03-transit-service-coordination.aspx |archive-date=February 2, 2017}}</ref><ref>{{cite web |date=March 2016 |title=Metro Transit Service Change: March 26, 2016 |url=http://www.kingcounty.gov/elected/executive/constantine/news/release/2016/March/09-metro-sound-transit-changes.aspx |publisher=King County Metro |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202013154/http://www.kingcounty.gov/elected/executive/constantine/news/release/2016/March/09-metro-sound-transit-changes.aspx |archive-date=February 2, 2017}}</ref> The ramp from International District/Chinatown station to the Interstate 90 express lanes was closed in September 2018 as part of preparations for East Link construction.<ref name="ST-2018Rainier"/>

===End of bus service===

In November 2015, King County Metro signed a $147 million agreement to sell Convention Place station to the Washington State Convention Center for redevelopment. The convention center plans to build a new expansion on the property, necessitating the closure of the station and transit tunnel to buses earlier than planned.<ref>{{cite news |last=Bhatt |first=Sanjay |date=November 18, 2015 |title=King County Metro, convention center reach $147M deal on site's sale |page=B1 |url=http://www.seattletimes.com/business/real-estate/king-county-metro-convention-center-reach-147m-deal-on-sites-sale/ |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170222064947/http://www.seattletimes.com/business/real-estate/king-county-metro-convention-center-reach-147m-deal-on-sites-sale/ |archive-date=February 22, 2017}}</ref> In 2017, Sound Transit and the Seattle Department of Transportation announced that the tunnel would become rail-only in 2019,<ref>{{cite news |last=Lindblom |first=Mike |date=June 25, 2017 |title=Reprieve for tunnel riders, but cascading projects to multiply Seattle's traffic woes |page=B1 |url=http://www.seattletimes.com/seattle-news/transportation/reprieve-for-tunnel-riders-but-cascading-projects-to-multiply-seattles-traffic-challenges/ |work=The Seattle Times |access-date=June 26, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170625231314/http://www.seattletimes.com/seattle-news/transportation/reprieve-for-tunnel-riders-but-cascading-projects-to-multiply-seattles-traffic-challenges/ |archive-date=June 25, 2017}}</ref> two years sooner than the planned switch in 2021 to coincide with the opening of the [[Northgate Link Extension]].<ref>{{cite news |last=Lindblom |first=Mike |date=September 16, 2015 |title=Light-rail trains to run every 6 minutes between Seattle and Sea-Tac |url=http://www.seattletimes.com/seattle-news/transportation/light-rail-trains-to-run-more-often/ |work=The Seattle Times |access-date=January 23, 2017 |url-status=live |archive-url=https://web.archive.org/web/20161011023510/http://www.seattletimes.com/seattle-news/transportation/light-rail-trains-to-run-more-often/ |archive-date=October 11, 2016}}</ref> Convention Place station was permanently closed on July 21, 2018, and was replaced with a set of bus stops on 9th Avenue and a new tunnel access ramp.<ref name="Times-CPS2018"/>

Bus service in the tunnel ended on March 23, 2019, with a ceremonial trip by a preserved Breda dual-mode bus at 1&nbsp;a.m.<ref>{{cite news |last=Switzer |first=Jeff |date=March 21, 2019 |title='The Last Dance:' Metro buses say goodbye to Downtown Seattle Transit Tunnel |url=https://kingcountymetro.blog/2019/03/21/the-last-dance-metro-buses-say-goodbye-to-the-downtown-seattle-transit-tunnel/ |work=Metro Matters |publisher=King County Metro |access-date=March 23, 2019}}</ref> The remaining 830 bus trips through the tunnel, serving approximately 37,000 riders on seven routes, were redirected onto surface corridors on 2nd, 3rd, 4th, 5th, and 6th avenues.<ref>{{cite news |date=February 20, 2019 |title=Downtown Seattle transit tunnel will close to buses in March |url=https://komonews.com/news/local/downtown-seattle-transit-tunnel-to-close-for-good-in-march |publisher=KOMO 4 News |access-date=February 21, 2019}}</ref><ref>{{cite news |last1=Millman |first1=Zosha |last2=Guevara |first2=Natalie |date=March 22, 2019 |title=Bus tunnel no more: Routes using downtown transit tunnel to move outside Saturday |url=https://www.seattlepi.com/local/transportation/article/Seattle-maximum-constraint-bus-tunnel-Saturday-13707009.php |work=Seattle Post-Intelligencer |access-date=March 23, 2019}}</ref> Metro and the city government also increased surface street capacity for buses by introducing all-door boarding for all 3rd Avenue and Westlake Avenue routes at 31 stops, improving signal timing, and adding a new northbound bus lane on 5th and 6th avenues.<ref>{{cite news |last=Groover |first=Heidi |date=February 21, 2019 |title=Do you rely on a bus through downtown? Big changes near |page=B1 |url=https://www.seattletimes.com/seattle-news/transportation/do-you-rely-on-a-bus-through-downtown-prepare-for-big-changes/ |work=The Seattle Times |access-date=February 21, 2019}}</ref><ref>{{cite press release |date=February 20, 2019 |title=More Metro in March: Added service, all-door boarding on Third Avenue, and buses say goodbye to the Downtown Seattle Transit Tunnel |url=https://www.kingcounty.gov/elected/executive/constantine/news/release/2019/February/20-metro-service.aspx |publisher=King County Metro |access-date=February 21, 2019}}</ref><ref>{{cite news |last=Groover |first=Heidi |date=March 25, 2019 |title=Buses no longer using Seattle's transit tunnel; Monday commutes test new routes |url=https://www.seattletimes.com/seattle-news/transportation/buses-are-out-as-downtown-transit-tunnel-shifts-to-rail-only-monday-commutes-will-test-new-bus-routes/ |work=The Seattle Times |access-date=March 25, 2019}}</ref>

During early 2020, Sound Transit built connections to East Link at International District/Chinatown station. Over a ten-week period that began in January 2020, four-car trains ran on a single track within the tunnel, with through-passengers transferring at Pioneer Square station via a temporary center platform, reducing frequency to 13–15 minutes.<ref>{{cite news |date=January 8, 2020 |title=Connect 2020 Link schedules adjusting to every 13-15 minutes |url=https://www.soundtransit.org/blog/platform/connect-2020-link-schedules-adjusting-to-every-13-15-minutes |work=The Platform |publisher=Sound Transit |access-date=January 8, 2020}}</ref> The tunnel was also closed for four weekends until work was completed in late March, after a week-long delay in testing. Frequency restrictions brought on by the project remained due to the [[COVID-19 pandemic in Washington (state)|coronavirus pandemic]] and local shutdowns.<ref>{{cite press release |date=March 22, 2020 |title=Connect 2020 concludes, ending Link light rail transfers at Pioneer Square and bicycle restrictions |url=https://www.soundtransit.org/get-to-know-us/news-events/news-releases/connect-2020-concludes-ending-link-light-rail-transfers |publisher=Sound Transit |access-date=March 24, 2020}}</ref><ref>{{cite news |last=Lindblom |first=Mike |date=January 2, 2020 |title=Light-rail riders can expect more crowded, less frequent trains as downtown track construction begins |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/light-rail-riders-can-expect-more-crowded-less-frequent-trains-as-downtown-track-construction-begins/ |work=The Seattle Times |access-date=January 2, 2020}}</ref> Sound Transit originally planned to assume full ownership of the tunnel in 2020,<ref>{{cite news |last=Lindblom |first=Mike |date=April 10, 2019 |title=Sound Transit is taking over the downtown transit tunnel. What are its plans for the vacant Westlake Station kiosk? |url=https://www.seattletimes.com/seattle-news/transportation/what-sound-transit-plans-for-the-vacant-westlake-station-kiosk-in-seattle/ |work=The Seattle Times |accessdate=September 12, 2022}}</ref> but later delayed plans due to the COVID-19 pandemic and issues with station escalators. The 36 escalators serving the downtown tunnel stations, which suffered from breakdowns and lengthy repairs, are planned to be repaired under a new contractor to replace [[Kone]].<ref>{{cite news |last=Lindblom |first=Mike |date=July 4, 2021 |title=Sound Transit's race to fix dozens of broken escalators in downtown Seattle |url=https://www.seattletimes.com/seattle-news/transportation/sound-transits-race-to-fix-dozens-of-broken-escalators-in-downtown-seattle/ |work=The Seattle Times |access-date=July 9, 2021}}</ref> Sound Transit took over maintenance operations on January 1, 2021, and signed a contract with [[Schindler Group]].<ref name="Times-Mar2023">{{cite news |last=Lindblom |first=Mike |date=March 19, 2023 |title=Seattle's bleak downtown light-rail stations have nowhere to go but up |url=https://www.seattletimes.com/seattle-news/transportation/seattles-bleak-downtown-sound-transit-stations-have-nowhere-to-go-but-up/ |work=The Seattle Times |accessdate=March 23, 2023}}</ref>

===Sound Transit ownership===

The full transfer of ownership was approved by Sound Transit on October 27, 2022, at no cost due to an agreement with Metro to pay off $87&nbsp;million of remaining debt incurred from its construction. As part of the transfer, $96&nbsp;million was budgeted for upgrades to elevators and escalators, fixing utilities and station elements, and cleaning soiled artwork.<ref>{{cite news |last=Lindblom |first=Mike |date=October 27, 2022 |title=Sound Transit takes ownership of aging downtown Seattle tunnel |url=https://www.seattletimes.com/seattle-news/transportation/sound-transit-takes-ownership-of-aging-downtown-seattle-tunnel/ |work=The Seattle Times |accessdate=October 27, 2022}}</ref> In September 2022, [[ORCA card]] readers were removed from the platforms and new signage and tactile markings added for fare paid zones.<ref>{{cite news |date=September 8, 2022 |title=Saying goodbye to card readers on platforms at downtown Link stations |url=https://www.soundtransit.org/blog/platform/saying-goodbye-to-card-readers-platforms-downtown-link-stations |work=The Platform |publisher=Sound Transit |accessdate=September 12, 2022}}</ref> Sound Transit plans to replace all 58 escalators and elevators in the transit tunnel over a nine-year period beginning in 2023 at a cost of $134&nbsp;million. In addition to wear and age, some pieces of equipment are also due for replacement because of flooding and rainwater seepage.<ref name="Times-Mar2023"/> {{as of|June 2023}}, 56 of the 58 elevators and escalators in the tunnel stations are in operation.<ref>{{cite news |last=Lindblom |first=Mike |date=June 17, 2023 |title=An escalator is revived at International District/Chinatown Station |url=https://www.seattletimes.com/seattle-news/transportation/an-escalator-is-revived-at-international-district-chinatown-station/ |work=The Seattle Times |accessdate=June 21, 2023}}</ref>

The tunnel was retrofitted from January to February 2024 to replace {{convert|500|ft|m}} of northbound track in the curve between University Street (now Symphony) and Westlake stations where the rails in the track had drifted apart by {{convert|1/8|in|cm}}. Other tunnel work, including the replacement of 58 bond boxes for signaling between the tracks, was also undertaken during the project, which had single-track service on weekdays and a full closure of the downtown section on weekends.<ref>{{cite news |last=Lindblom |first=Mike |date=January 11, 2024 |title=Prepare for Seattle transit delays as downtown light rail work begins |url=https://www.seattletimes.com/seattle-news/transportation/prepare-for-seattle-transit-delays-as-downtown-light-rail-work-begins/ |work=The Seattle Times |accessdate=January 11, 2024}}</ref><ref>{{cite press release |date=February 4, 2024 |title=1 Line service returns to normal Monday, Feb. 5 |url=https://www.soundtransit.org/get-to-know-us/news-events/news-releases/1-line-service-returns-to-normal-monday-feb-5 |publisher=Sound Transit |accessdate=February 4, 2024}}</ref> The first week of the project resulted in crowding on station platforms and delays exceeding the scheduled 26-minute frequency for single-tracking trains.<ref>{{cite news |last=Lindblom |first=Mike |date=January 18, 2024 |title=Light rail repair work in Seattle leads to overflow crowds and delays |url=https://www.seattletimes.com/seattle-news/transportation/light-rail-repair-work-in-seattle-leads-to-overflow-crowds-and-delays/ |work=The Seattle Times |accessdate=January 22, 2024}}</ref>

==References==
{{reflist}}

==External links==
{{Attached KML}}

*{{commons category-inline|Downtown Seattle Transit Tunnel}}
*[https://kingcounty.gov/depts/transportation/metro/travel-options/bus/transit-tunnel.aspx King County Metro: Downtown Seattle Transit Tunnel]

{{Bridges of Seattle}}
{{Puget Sound Transit|show}}

[[Category:1990 establishments in Washington (state)]]
[[Category:Bus rapid transit in Washington (state)]]
[[Category:Busways]]
[[Category:Link light rail]]
[[Category:Railroad tunnels in Seattle]]
[[Category:Sound Transit Express]]
[[Category:Trolleybus transport in the United States]]
[[Category:Tunnels completed in 1990]]
[[Category:Underground rapid transit in the United States]]
[[Category:1500 V DC railway electrification]]