Trolleybus
From Wikipedia, the free encyclopedia
A trolleybus (also known as electric bus, trolley bus, trolley coach, trackless trolley, trackless tram or simply trolley) is a bus powered by two overhead electric wires, from which it draws electricity using two trolley poles. Two poles are required in order to accommodate the return current, which cannot pass to the ground as in the case of an electric tram or streetcar since trolleybuses use rubber tires, rather than steel wheels on rail. There are trolleybuses in many cities around the world.
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[edit] Background
The history of the trolleybus dates back to 29 April 1882, when Dr. Ernst Werner von Siemens ran his "Elektromote" in a Berlin suburb. This experimental demonstration continued until 13 June 1882, after which there was little progress in Europe, although separate experiments were conducted in the USA. The next development was when Lombard Gérin operated an experimental line at the Paris Exhibition of 1900 after four years of trials. Max Schiemann made the biggest step when on 10 July 1901 the world's first passenger-carrying trolleybus operated at Bielathal (near Dresden) in Germany. Schiemann built and operated the Bielathal system, and is credited with developing the under-running trolley current collection system, with two horizontally parallel overhead wires and rigid trolleypoles spring-loaded to hold them up to the wires. Although the Bielathal system only operated until 1904, Schiemann had developed what is now recognised as the standard trolleybus current collection system. In the early days, however, there were a few different methods of current collection being developed. The Cedes-Stoll system, designed by Carl Stoll, was once operated near Dresden between 1902 and 1904, and in Vienna. The Lloyd-Köhler or Bremen system was tried out in Bremen, and the Filovia was demonstrated near Milan.
Leeds and Bradford became the first cities to operate passenger-carrying trolleybuses in the UK on 20 June 1911. Bradford was also the last to operate trolleybuses in the UK, the system closing on 26 March 1972. The last rear entrance trolleybus in Britain was also in Bradford and is now owned by the Bradford Trolleybus Association. Birmingham was the first to replace a tram route with trolleybuses, while Wolverhampton under the direction of Charles Owen Silvers was responsible for turning the "trackless tram" into the trolleybus. There were 50 trolleybus operations in the UK in total, London's being the largest. By the time trolleybuses arrived in Britain in 1911, the Schiemann system was well established and was the most common, although the short-lived Stockport operation used the Lloyd-Kölher system and Keighley used the Cedes-Stoll system.
In the USA, some cities, led by the Brooklyn-Manhattan Transit Corporation (BMT—New York), subscribed to the all-four concept of using buses, trolleybuses, trams (in U.S. called streetcars, trolleys or light rail) and rapid transit subway and/or elevated lines (metros), as appropriate, for routes ranging from lightly-used to the heaviest trunk line. Buses and trolleybuses in particular were seen as entry systems that could later be upgraded to rail as appropriate. Although the BMT in Brooklyn built only one trolleybus line, other cities, notably San Francisco, California and Philadelphia, Pennsylvania, built larger systems and still maintain "all-four". If one includes cable cars as another mode, San Francisco could be called "all-five," as its cable cars provide general transportation as well as being a tourist attraction.
[edit] Advantages
Trolleybuses are particularly advantageous on hilly routes, as electric power is more effective than diesel power for climbing steep hills, and trolleybuses' rubber tires have better adhesion than streetcars' steel wheels on steel rails. San Francisco and Seattle, USA, both very hilly places, use trolleybuses.
Like other electric vehicles, trolleybuses are often seen as more environmentally friendly than fossil fuel or hydrocarbon-based vehicles (gasoline, diesel, alcohol, etc.), but the power is not "free", having instead to be produced at centralised power plants, with attendant transmission losses.
On the other hand, centrally-produced power has the advantage of being more efficient, not bound to a specific fuel source and more amenable to pollution-control as a single-source supply than are individual vehicles with their own engines that exhaust noxious gases and particulates at street level. Moreover, some cities, like Calgary, Alberta, run their commuter light rail networks using wind energy [1], which is effectively emission-free once the turbines are built and installed. A further advantage of trolleybuses is that they can generate electric power from kinetic energy whilst braking, a process known as regenerative braking.
Also, unlike buses or trams, trolleybuses are almost silent, lacking the noise of a diesel engine or wheels on rails. Such noise as there is tends to emanate from auxiliary systems such as power steering pumps and air conditioning. Early trolleybuses without these systems were even quieter, and in the UK at least were often referred to as the "Silent Service". The quietness did have its disadvantages though, with quite a number of pedestrians falling victim to what was also known as "the Silent Death".
Trolleybuses are specially favoured in locations where hydropower is abundant and cheap. Examples of this are the extensive trolleybus systems in Vancouver, British Columbia, Canada and Seattle, Washington, USA. Seattle benefits doubly, with steep gradients near the Downtown waterfront and on Queen Anne, First, and Capitol Hills.
Trolleybuses are used extensively in large European cities such as Athens, Bucharest, Moscow, Saint Petersburg, Sofia, Kiev, Belgrade and Vilnius, as well as smaller ones, like Lausanne, Salzburg and Nancy. Cities, especially those built on hills, have chosen trolleybuses over diesel buses because the electric motor can produce much more torque than a diesel engine. Moreover, the electric motor can be temporarily "overpowered", that is, more than the normal power can be obtained it for a short period of time, e.g. when climbing a steep hill. Also, realising the advantages of these zero-emission vehicles, some other European cities have started to expand their systems again. Other cities such as Lecce will introduce new trolleybus systems.
Some have suggested that the trolleybus will become obsolete in a future hydrogen economy. However, direct electric transmission, as used in trolleybuses, is far more efficient (by a factor of two or more) than conversion of energy into hydrogen, transportation and storage of the hydrogen and its conversion back into electricity by fuel cells.
China is experimenting with a new form of electric bus that runs without powerlines. This bus runs on power stored in large onboard supercapacitors, which are quickly recharged at bus stops. Prototypes were being tested in Shanghai in early 2005.
[edit] Restraints
With the introduction of hybrid designs the trolleybus is no longer tied to its overhead trolley wires. Re-routings, temporary or permanent, are not usually readily available outside of "downtown" areas where the buses may be re-routed via adjacent business area streets where other trolleybus routes operate. Dewirements sometimes occur, leaving the bus stranded without power, although these events are relatively rare on systems with well-maintained overhead wire, hangers, fittings and "contact shoes." Some systems, such as Muni in San Francisco and TransLink in Vancouver, have circumvented this problem by installing battery packs on their trolleybuses to allow them to drive for short distances away from the wires. Also Supercapacitors may be used to drive small distances without connections to the grid. Boston is using dual-mode buses on its new Silver Line that run on overhead electricity on a fixed right of way and then transition to city streets using diesel power. In Philadelphia, Pennsylvania, whose five trolleybus lines have been suspended for partial reconstruction, new trolleybuses on order will also have a means of operating for short distances off the overead wires. In Athens, Greece, which has an extensive trolleybus system, in 2003-2004 all trolleybuses were replaced with new vehicles that are equipped with a diesel engine that allows them to run off-line for a considerable distance.
Limitations in the creation of power lines also limits the use of trolleybuses and further restrictions may also apply where when super-tall trucks need to use a route, preventing the installation of overhead lines. Nevertheless the installation is quicker and cheaper than a tramways system.
Trolleybuses can pass one another in regular service, if two separate sets of wires with a switch are provided.
Trolleybuses were generally implemented only when they confer one of the advantages listed above, because of the high cost of their infrastructure compared to the standard bus. With increasing diesel costs and particle and NOx problems in cities, trolleybuses may yet be seen as the best suited relief for medium sized cities.
While at one time many cities operated this mode of transport, it is on average uncommon today in North America, though it is still a common form of transport in many European, Russian, Brazilian and Chinese cities, generally occupying the niche between street railways and diesel-powered buses.
[edit] Trolleybus wire switch
Trolleybus wire switches (in some countries referred to as "frogs") are a standard piece of equipment in places where the line forks into two others or two lines join into one. The switch pictured here is a fully automatic one; the driver controls it by means of the application of power to the bus's motor. If the "straight through" option is desired, the driver coasts through the switch. All parts of switch are still in their initial positions when trolleybus goes under the switch. If the "turn" option is desired, the driver passes the switch while applying power to the bus's motor. The switch detects the voltage drop in the wires caused by the draw on power of the motor and activates a small electromagnet to change the switch position. After a short period of time the electromagnet automatically turns off and, due to attached spiral coils, the switch returns to the normal "straight through" configuration.
[edit] Trolleybuses in Russia
The first trolley vehicle in Russia was built in Saint Petersburg in 1902 on Frese machinebuilding factory. It utilised a carriage-type current receiver like the early von Siemens prototypes. There was no attempt to organize passengers or cargo services at this time.
The first operational trolleybus service was introduced in 1933 in Moscow. In Soviet cities with underground metropolitan railways, trolleybus systems were intended to replace tramcars. In reality such plans were partially performed in 1950s rather than in 1930s. The first Soviet-made passenger trolleybus LK-1 was named after Politburo member Lazar Kaganovich. It was a dangerous and unreliable vehicle, quickly replaced by more advanced YaTB vehicles. These cars, both passenger and cargo, were the mainstay of Soviet trolley fleet before Great Patriotic War. At this time new trolleybus systems were opened in Leningrad, Kiev (Ukraine) and few other major Soviet cities.
It may appear strange that in the time of the Great Patriotic War (World War II), new trolleybus systems were opened in USSR. The need for mass transit in cities away from the front was urgent, but construction of tram lines was too expensive and time-consuming. Buses were largely mobilized to the Red Army as staff and medical vehicles. The remains of the bus fleet quickly stalled due to fuel shortages. The trolleybuses proved a good solution. Some vehicles, wires and other equipment were evacuated from Moscow in 1941; these materials were used for erecting new lines and systems in other cities. In the front-line city of Leningrad, trolleybus service ceased operations in November 1941 and was not restored until the end of the war. City trams were relaunched in April 1942 and performed without interruption under siege conditions. This restored Soviet plans of mass transit development in the form of co-existence of subways, trams, and trolleys.
The postwar period saw an explosion of development and expansion of trolleybus systems in the Soviet Union. Many cities and towns introduced passenger and cargo trolleybus services, sometimes interfering with tram operations. Production at the time was limited to the monopoly Zavod imeni Uritskogo (ZiU, named after Moisei Uritsky). It produced thousands of MTB-82, ZiU-5, ZiU-9 passenger trolleybuses for domestic purposes and for export. ZiU-9s were sold to Greece, Colombia, Argentina and eastern bloc countries. Three ZiU-9 cars were on loan in 1973 for testing purposes in Helsinki, Finland.
The collapse of the Soviet Union led to insufficient funding for many municipal trolleybus systems, but they proved more resilient than municipal tram or bus operations. There are no closed trolleybus systems in areas of modern Russia that are at peace. The trolleybus system in Grozny was completely destroyed in the First Chechen War. Reconstruction is in planning. There are two systems with uncertain futures, in Voronezh and Shakhty. In other cities the development of trolleybus passenger services continues. Two new systems were introduced in Moscow suburbs Khimki and Vidnoe in the second half of 1990s. ZiU has lost its monopoly in producing trolley vehicles. Today a number of domestic factories offer trolleybuses for the Russian market.
[edit] Preservation
The world's largest collection of preserved trolleybuses is at The Trolleybus Museum at Sandtoft in England. Examples are also preserved at The East Anglia Transport Museum and The Black Country Living Museum in England, the Brisbane Tramway Museum and the Adelaide Electric Traction Museum in Australia. In Foxton, New Zealand, preserved trolleybuses operate on the public highway on their own system.
The Bradford Trolleybus Association is currently restoring Bradford Trolleybus 758, the last rear entrance trolleybus in Britain. Bradford Trolleybus 758 is kept at The Trolleybus Museum at Sandtoft.
In Lausanne, the Association Retrobus preserves old trolleybuses (from 1932 to 1964) and enables them to circulate in town, especially on summer weekends.
The Illinois Railway Museum also maintains a historical collection of trolleybuses from Chicago, Dayton, Ohio, Cleveland, Des Moines, Vancouver and Milwaukee.
Russian transport museums have a variety of historic trolleybuses made by local manufacturers. In Moscow vintage vehicles are only available for public in transport-dedicated exhibitions and parades of old vehicles in different celebration days. In Saint Peterburg and Nizhny Novgorod museum cars are also may be hired for city excursions and parties.
 Trolleybus public transfer in Bratislava, Slovakia |
 An articulated trolleybus in Arnhem, Netherlands |
 Vancouver's third generation of trolleybuses (New Flyer / Vossloh Kiepe) |
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 Muni Trolleybus crossing tracks of the San Francisco cable car system |
 Vintage ZiU-5 trolleybus on the streets of Nizhny Novgorod, Russia |
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 Articulated trolleybus in Seattle, Washington. |
[edit] See also
- Gyrobus
- List of cities with trolleybuses
- List of cities that no longer have trolleybuses
- Low-floor trolleybuses
- Tourist trolley
[edit] Books
Sebree, Mac, and Paul Ward. 1973. “Transit’s Stepchild, the Trolley Coach” (Interurbans Special 58) (ASIN B0006C9ZOE). Los Angeles: Interurbans.
Sebree, Mac, and Paul Ward. 1974. "The Trolley Coach in North America" (Interurbans Special 59). (ASIN B0006CEBZC) Los Angeles: Interurbans.
Mick Leak. 2006. "The Story Of Britain's Last Rear Entrance Trolleybus In Public Service - Bradford 758. Published By The Bradford Trolleybus Association. Bradford. United Kingdom.
[edit] Periodicals
"Trolleybus Magazine" (ISSN 0266-7452). National Trolleybus Association (UK). Bimonthly.
"Trackless" The Quarterly Magazine Published By The Bradford Trolleybus Association For Its Members.
[edit] References
- All Time List of North American Trolleybus Systems, accessed January 30, 2004
- British trolleybuses
- Trolleybuses at the BCLM
[edit] External links
- The Bradford Trolleybus Association.
- The Buses of China(Forum, Simp.Chinese)
- Bibliography of the Electric Trolleybus (Richard DeArmond)
- The Electric Trolleybus Web Site
- Budapest Trolleybuses
- Transport Photogallery
- British trolleybuses
- Arnhem Trolleystad
- Trolleybuses in Europe
- (Spanish) Sistema de Transporte Eléctrico del Distrito Federal (Mexico)
- London Trolleybus Photos on the Tramway Information Website
- West Ham's Cedes Stoll Trolleybus
- Transit World - Has photos of Trolleybuses in Vancouver & Edmonton (Canada), and Wellington (New Zealand)
- Trolleybus Town Eberswalde (former East Germany) — available in English, German and Russian.
- (German) Trolleybus in Berlin (Germany)
- (Russian) Trolleybus cities of Russia
- The Trolleybus Museum at Sandtoft
- (Russian)/(Ukrainian) "Seventy years of Kiev trolleybus", Zerkalo Nedeli (the Mirror Weekly), December 10-16, 2005, in Russian and in Ukrainian.
- Tom's North American Trolleybus Pictures
- Edmonton Transit System
- Vancouver Transit
- (German) Trolleybus museum in Solingen (Germany) - has working buses in its collection, which run on the trolleybus system in Solingen
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