Cable transport

Cable car at Zell am See in the Austrian Alps

Cable transport is a broad class of transport modes that have cables as the foundation for transporting things or people, often in vehicles called cable cars. The cable may be driven or passive; items may be moved by pulling, sliding, sailing, or by drives within the object being moved on cableways. The use of pulleys and balancing of loads going up and down are common elements of cable transport.They are also used in mountainous areas.

Common modes of cable transport are:

• Aerial lifts, such as:
  • Aerial tramway
  • Chairlift
  • Funitel
  • Gondola lift
  • Ski lift
  • Zip line
• Surface lifts, such as:
  • Cable railways
  • Cable car
  • Cable ferry
  • Funicular
  • Surface lift
• Vertical lifts, such as:
  • Elevator

History

Cable drawn transport has been known of since at least 250 B.C. and received much attention during the industrial revolution. During said period of time, several new methods were thought of and implemented including the use of steel cable to allow for greater load support and larger systems. Funicular railways were instituted in San Francisco in 1872 and as attention grew, aerial tramways became a greater focus shortly after but only coming into commercial use for passengers in the 1900s.

The first cable cars

The idea for a cable hauled street railway in California belonged to Benjamin Brooks, who was not able to accomplish it due to the lack of capital. Instead, Andrew Hallidie, a Scottish emigre, gave San Francisco the first effective and commercially successful route, using steel cables. Hallidie was a manufacturer of such cables. The system featured a man operated grip, which was able to start the carrier and stop it safely as well. The rope that was used allowed the independent use of more than one cable car at once and soon Hallidie`s concept was extended to the whole city of San Francisco. The carriers had a capacity of between 14 and 16 people but during the rush hours, they could fit between 24 and 26 passengers without any problems. The tickets cost about 5 cents, which was relatively expensive for back then but still seems unbelievable compared to the price today – approximately 5 dollars!

Actually, from the historical point of view, the San Francisco Cable Car was implemented after the one in London and Blackwall Railway, built in 1840, but the technology that Andrew Hallidie suggested was far more practical and better and in a way similar to the systems in practice today. The London one used fiber, instead of steel ropes and collars to make the connection from the grip to the rope. This caused a series of technical and safety issues, which led to replacing the lines with steam vehicles by 1848.

More recent developments

The Westside and Yonkers railway opened in 1868.

More recent developments are being classified under the type of track that their design is based upon. After the success of this operation, several other projects were initiated in New Zealand and Chicago. The social climate around pollution is allowing for a shift from cars back to the utilization of cable transport due to their advantages. However, for many years they were a niche form of transportation used primarily in difficult-to-operate conditions for cars (such as on ski slopes as lifts). Now that Cable Transport Projects (CTP) are on the increase the social effects are beginning to become more significant.

Social effects

The La Paz cable car system in Bolivia is both the longest and highest urban cable car network in the world.

There are a few notable advantages to using cable transport including:

• Electric drive in a main drive station - The vehicles themselves operate without an engine. This significantly reduces construction and maintenance costs.
• Lightweight carriers.
• High safety – Accidents relating to cable transport are extremely rare. Over 10,000 CTPs transport billions of people each year yet cable transports have some the best safety records of any mode of transport.
• Reduced operator number – Cable cars require no drivers which reduce costs and increases safety.
• Reliability and efficiency – Modern cable transport has, on average, less than one minute wait times between vehicles.
• Energy Efficient – Due to cable transport’s use of gravity and counterbalancing, many systems generate are self-sufficient in terms of power during off-peak times.
• High speed – CTPs can travel up to 45 km/hr. In addition to this, by their very nature, they take the most direct route to their destinations and aren’t subject to delays such as traffic jams.
• Large capacity – An aerial CTP can transport up to 4,000 people in one direction per hour. Ground-based increases this to 10,000 people.
• Flexible – CTPs aren’t just limited to transporting people but have a variety of applications. For example, a system in Slovakia transports newly manufactured cars to and from a testing facility.
• No influence of the carrier - runway friction coefficient.
• Intrinsic safety against carrier collision along the line.

The Portland Aerial Tram

Comparison with other transport types

When these are offset against the advantages of using other modes of transport such as trains or cars, the volume of people to transport over a period of time and the start-up cost of the project must be considered. In areas with extensive road networks, personal vehicles offer greater flexibility and range. More remote places like mountainous regions and ski slopes may be difficult to link with roads and so a CTP is a much easier approach. A CTP system may also require fewer invasive changes to the local environment. The use of Cable Transport is not limited to such rural locations as skiing resorts; it can be used in urban development areas. Their uses in urban areas include funicular railways, gondola lifts and aerial tramways.

Safety

Although Cable Transport technology has advanced to cope with various weather conditions, there are many cases where accidents still occur. However it still experiences the fewest number of injuries, deaths, etc. per 1000 passengers when compared with other forms of transports according to the GondolaProject. This is a further advantage of their use as public transport despite their limitations in capacity. Cable Cars experienced the lowest number of accidents, injuries and deaths in Switzerland during 2008-2009 according to the gondolaproject. However, the overall safety of cable transportation was reconsidered after a major tragedy involving cable cars occurred in Saint-Etienne en Devoluy, which killed 21 people in July 1999. Although the technology behind cable cars ensures the safety when using them, cable transportation – cable cars especially – are most commonly used in very hazardous conditions. These conditions include being at very high heights, usually above dangerous mountain or dense forest terrain and also in parts of the world that have extreme weather conditions such as high winds and snow. For some people this raises concerns about the risks using this type of transportation poses however, thousands of people use cable transportation daily without any issue around the world in all types of conditions, proving that the developments have made cable transportation one of the safest ways of transport with the fewest amount of casualties.

Accidents

Although accidents involving cable transport are a rare occurrence, there have still been serious incidents:

• On Wednesday 25 July 2012, passengers of a tour cable car were stuck 90 meters high in the air as there was a power failure which caused the cart to suddenly stop over the river Thames in the gondolas. The fault happened at 11:45am and lasted roughly for 30 minutes. Luckily no passengers were injured however, at the time this was the first problem to ever hit the Emirates Airline.
• Nevis Range, near Fort William, Scotland, a cable car was reported to have derailed and crashed to the ground seriously injuring all 5 passengers on 13 July 2006. Another car on the same rail also slid back down the rails when the crash happened. Following the incident, 50 people were left stranded at the station whilst the staff and aid helped the passengers of the crashed car.
• The cable car accident in Cavalese, Italy which occurred on 9 March 1976 is considered the worst aerial lift accident in history. The car crashed off the rails and fell 200 meters down a mountain side, also crashing through a grassy meadow before coming to a halt. The tragedy caused the death of 43 people and four lift officials were jailed for charges regarding the accident
• The Kaprun disaster was a fire that occurred in an ascending train in the tunnel of the Gletscherbahn Kaprun 2 funicular in Kaprun, Austria, on 11 November 2000. The disaster claimed the lives of 155 people, leaving 12 survivors (10 Germans and two Austrians) from the burning train. It is considered as the worst cable car accident in history.

Future of Cable Transport

The future of the cable transport certainly looks promising, as the need for reducing the transportation costs and air pollution is rapidly growing. Also, it is necessary to take into consideration the various cable-APM (Automated People Mover) characteristics, because they possess different properties, suit different needs and therefore can be used to solve a variety of transportation issues. The cable system transport can be classified in the following way:

• Ski area cableways, with some stations, carriers and control system modifications.
• Shuttles running on a dedicated track with fixed grips or with haul rope loop switching at the stations, with standing or very slowly running cable and with no acceleration-deceleration device.
• Systems running on a dedicated track with detachable carriers and acceleration-deceleration devices in each station.

Of course, each of these instances are accompanied by certain advantages and limitations. The ski area cableways technology is a perfect solution when there is a large vertical drop or the cabins are required to cross obstacles such as rivers or lakes. However, the setback is the difficulty to design lines with numerous stations and corners, as well as the visual pollution of the towers. The shuttle systems impose the usage of a massive bridge, especially if the distance between the towers is wide. This implies the systems would consist of long cables and a lot of intermediate stations, which could result either in serious capacity decrease or in needs of vast carriers. The mini-metro technology does not pose such issues, as the carriers are way smaller and are able to cut corners, but the real problem is connected with the number of stations. The existing technology uses a large number of tires, belts, and gears for the execution of the acceleration, the deceleration and the actual process of driving. There are currently some developments about the future improvement of this type of cable transport, but it still remains a major issue to be resolved.

External links

• Melbourne's cable trams on YouTube
• San Francisco's Cable Cars & Motor Cars; 1900-1940s - with 1906 Earthquake on YouTube
• World Cable Car's - Danger in the Skies on BBC