Trolleybus
This differs from a tram or streetcar, which normally uses the track as the return path, needing only one wire and one pole (or pantograph).
[5] The trolleybus dates back to 29 April 1882, when Dr. Ernst Werner Siemens demonstrated his "Elektromote" in a Berlin suburb.
[9] The next development was when Louis Lombard-Gérin operated an experimental line at the Paris Exhibition of 1900 after four years of trials, with a circular route around Lake Daumesnil that carried passengers.
[10] Max Schiemann on 10 July 1901 opened the world's fourth passenger-carrying trolleybus system, which operated at Bielatal (Biela Valley, near Dresden), Germany.
[14] Trackless trolleys were the dominant form of new post-World War I electric traction, with extensive systems in among others, Los Angeles, Chicago, Boston, Rhode Island, and Atlanta; San Francisco and Philadelphia still maintain an "all-four" fleet.
Some trolleybus lines in the United States (and in Britain, as noted above) came into existence when a trolley or tram route did not have sufficient ridership to warrant track maintenance or reconstruction.
This mode of transport operates in large cities, such as Belgrade, Lyon, Pyongyang, São Paulo, Seattle, Sofia, St. Petersburg, and Zurich, as well as in smaller ones such as Dayton, Gdynia, Lausanne, Limoges, Modena, and Salzburg.
Since the 1980s, systems such as Muni in San Francisco, TransLink in Vancouver, and Beijing, among others, have bought trolleybuses equipped with batteries to allow them to operate fairly long distances away from the wires.
Trolleybuses can optionally be equipped either with limited off-wire capability—a small diesel engine or battery pack—for auxiliary or emergency use only, or full dual-mode capability.
A simple auxiliary power unit can allow a trolleybus to get around a route blockage or can reduce the amount (or complexity) of overhead wiring needed at operating garages (depots).
In Philadelphia, new trackless trolleys equipped with small hybrid diesel-electric power units for operating short distances off-wire were placed in service by SEPTA in 2008.
A limited number of the Breda dual-mode buses had their diesel engines removed, and operated exclusively as trolleybuses until 2016.
[30] IMC (In Motion Charging) trolleybuses are equipped with a light-weight battery, the size of which is adapted to the line profile used.
The on-board battery is charged while the vehicle is in motion under the overhead wires and then allows off-wire travel for significant distances, often in excess of 15 km.
The wires are attached to poles next to the street and carefully stretched and mounted so that they are the same width apart and same height over the road (usually about 18 to 20 feet (~5.7m)).
This skew means that a trolleybus going straight through will not trigger the switch, but a trolleybus making a turn will have its poles match the contacts in a matching skew (with one pole shoe ahead of the other), which will trigger the switch regardless of power draw (accelerating versus coasting).
Well over 200 different trolleybus makers have existed – mostly commercial manufacturers, but in some cases (particularly in communist countries), built by the publicly owned operating companies or authorities.
[5]: 91–125 Of the defunct or former trolleybus manufacturers, the largest producers in North America and Western Europe – ones whose production totalled more than 1,000 units each – included the U.S. companies Brill (approx.
1,750), British United Traction (BUT) (1,573), Leyland (1,420) and Sunbeam (1,379); France's Vétra (more than 1,750); and the Italian builders Alfa Romeo (2,044) and Fiat (approx.
Current trolleybus manufacturers in western and central Europe include Solaris, Van Hool, and Hess, among others.
In Russia ZiU/Trolza has historically been the world's largest trolleybus manufacturer, producing over 65,000 since 1951, mostly for Russia/CIS countries, but after its bankruptcy, its facilities were partially loaned out to PC Transport Systems.
[47]: 61 The Americans with Disabilities Act of 1990 required that all new transit vehicles placed into service after 1 July 1993 be accessible to such passengers.
The Lausanne system dealt with this dilemma in the 1990s by purchasing new low-floor passenger trailers to be towed by its high-floor trolleybuses,[54] a choice later also made by Lucerne.
[55] Wellington, New Zealand, took delivery of its first low-floor trolleybus in March 2003,[56] and by the end of 2009 had renewed its entire fleet with such vehicles.
[45]: 134 With regard to non-passenger aspects of vehicle design, the transition from high-floor to low-floor has meant that some equipment previously placed under the floor has been moved to the roof.
[48] Some transit operators have needed to modify their maintenance facilities to accommodate this change, a one-time expense.
Most builders of double-deck trolleybuses were in the United Kingdom, but there were a few, usually solitary, instances of such trolleybuses being built in other countries, including in Germany by Henschel (for Hamburg); in Italy, by Lancia (for Porto, Portugal); in Russia, by the Yaroslavl motor plant (for Moscow) and in Spain, by Maquitrans (for Barcelona).
[5] British manufacturers of double-deck trolleybuses included AEC, BUT, Crossley, Guy, Leyland, Karrier, Sunbeam and others.
[5] In 2001, Citybus (Hong Kong) converted a Dennis Dragon (#701) into a double-decker trolleybus,[59] and it was tested on a 300-metre track in Wong Chuk Hang in that year.
[59] Hong Kong decided not to build a trolleybus system, and the testing of this prototype did not lead to any further production of vehicles.
