Canal Street railroad bridge

The present bridge was constructed for the Pennsylvania Railroad to replace a two-track swing bridge at the same location. The necessity to allow both continued use of the swing bridge and unimpeded river traffic during building work complicated construction of the bridge. The chosen solution was to construct the bridge in the raised position above the old bridge, then demolish the old bridge once construction was completed. The bridge was designed by Waddell & Harrington, and fabricated and erected by the Pennsylvania Steel Company.^[3]

Construction of the south tower began on September 4, 1913. When the two 185-foot (56 m) towers were completed, falsework for the main span was constructed in a fan shape that allowed the main span to be constructed in the raised position 130 feet (40 m) above the river. The bridge was built from steel and metal.^[6]

The bridge carries two railroad tracks across the Chicago River at an angle of about 40 degrees to the center line of the river. Upon completion, the main span could be raised 111 feet (34 m) in about 45 seconds.^[3] By 1916, each day the bridge was crossed by about 300 trains, and was raised for river traffic about 75 times.^[7]

There are proposals for an additional or replacement bridge at Canal Street to support the full high-speed, high-frequency build out of the St. Louis-Chicago Lincoln Service passenger rail line.^[4][8]

When it was constructed in 1914, its 1500-ton main span was the heaviest of any vertical lift bridge in the United States.^[6] It is the only vertical-lift bridge across the Chicago River.

• List of bridges documented by the Historic American Engineering Record in Illinois