A trolleybus is an electric bus that draws power from dual overhead wires using spring-loaded trolley poles. Two wires, and two trolley poles, are required to complete the electrical circuit. This differs from a tram or streetcar, which normally uses the track as the return path, needing only one wire and one pole. They are also distinct from other kinds of electric buses, which usually rely on batteries. Power is most commonly supplied as 600-volt direct current, but there are exceptions.
Guided Light Transit was the name of guided bus technology and associated infrastructure manufactured by Bombardier Transportation. Two GLT prototypes were designed and tested from 1987 onwards by BN in the region of Rochefort in Belgium. It was eventully installed in two French cities: Nancy and Caen. The Caen system was closed in 2017 and replaced by conventional trams, while the Nancy system was closed in March 2023 and is to be replaced by trolleybuses.
The Caen guided light transit or Caen TVR, locally known as "the Tram", was an electrically powered guided bus system in Caen, France, which used Bombardier Guided Light Transit technology.
A rubber-tyred tram is a development of the guided bus in which a vehicle is guided by a fixed rail in the road surface and draws current from overhead electric wires.
The Nancy Guided Light Transit or TVR was a guided trolleybus system in Nancy, France. The system used Bombardier's TVR technology. It encompassed one era, from 2000 to 2023, of the Nancy trolleybus system and replaced the conventional trolleybus service in Nancy during that period. The GLT/TVR system was closed on 12 March 2023, and is to be replaced by conventional trolleybuses serving the same route.
The Lausanne trolleybus system forms part of the public transport network of Lausanne, in the canton of Vaud, Switzerland. The system has been in operation since 1932 and is the third-oldest surviving trolleybus system in the world, after those of Shanghai and Philadelphia.
The Ashgabat trolleybus system formed part of the public transport network in Ashgabat, the capital city of Turkmenistan. It was the only trolleybus system ever in that country.
The Coimbra trolleybus system formed part of the public transport network in the city of Coimbra, Portugal. Opened in 1947, it supplemented, and then eventually replaced, the Coimbra tramway network. Service was suspended in March 2021 because of road construction, and officials stated that the suspension was temporary, but in late 2022 the mayor indicated that any resumption of trolleybus service would not occur until after completion of construction of a new Bus Rapid Transit line, around late 2024. However, in July 2024, the city council voted not to resume service – to make the suspension a permanent closure – albeit with a proposal floated for a future tourist trolleybus operation along the banks of the Mondego River, without further detail given.
The Fribourg trolleybus system forms part of the public transport network in Fribourg, capital of the canton of Fribourg, Switzerland. The system also serves the neighbouring municipalities of Villars-sur-Glâne and Givisiez, using one line in each case.
Louis Lombard-Gérin was a French engineer involved in pioneering the trolley bus.
The Nancy trolleybus system is part of the public transport network of the city of Nancy, France, and the neighboring comunes (municipalities) of Essey-lès-Nancy, Saint-Max and Vandœuvre-lès-Nancy. The trolleybus system opened in September 1982, and by one year later it had grown to three fully trolleybus routes. Three additional services were introduced that did not require any additional overhead trolley wires, as the fleet consisted of Renault dual-mode buses that could use the wiring of route 3 and then continue in diesel mode beyond the end of the wiring. Trolleybus service on route 3 ended in 1996, leaving only routes 4 and 19 in operation.
Franche-Comté 
Media related to Trolleybuses in France at Wikimedia Commons
