Trolleybus

A trolleybus in Arnhem
An electric trolleybus (or trolley bus) is a bus powered by two overhead electric wires, from which the bus draws electricity using two trolley poles (one for the return current, which can not pass to the ground as in the case of a tram). Unlike light rail, trolleybuses use rubber tires rather than steel wheels on rail.

Table of contents

1 Advantages
2 Problems with Trolleybuses
3 Cities that no longer have trolley buses

3.1 United States
3.2 United Kingdom
3.3 Other countries

4 External links

Advantages

Trolleybuses are particularly important in hilly cities, as the electric power is more effective than diesel in climbing steep hills.

Like other electric vehicles, trolleybuses are often seen as more environmentally friendly than hydrocarbon based vehicles such as buses, but the power is not "free", and instead has to be produced at centralised power plants.

One advantage that is rarely used in other vehicles is that they can generate electric power from kinetic power whilst braking, a process known as regenerative braking. Furthermore, trolleybuses demand a network of wires above the streets.

Problems with Trolleybuses

As trolleybuses do not follow a track, it is possible for them to come off the route and hence off the electric powerlines above and then get stuck.

While at one time numerous cities operated this mode of transport, it is uncommon today.

See List of cities with trolleybuses for cities which still have electric trolleybuses.