Trolley buses are the oldest type of electric buses and have been in use for more than a hundred years. These simple, tough and reliable vehicles draw their energy from an overhead line. Like all other electric vehicles, trolley buses generate virtually no emissions and can also be driven using renewable energy sources. Passengers appreciate this quiet and convenient manner of travelling. Worldwide, 305 cities operate trolley bus lines, 149 of them are located in Europe. Incidentally, Zwickau also used trolley buses between 1938 and 1977.

Unfortunately, nowadays in Germany, only three cities out of 74 still have their trolley bus lines. This is due to different reasons. One of those is that to date, trolley buses need a continuous catenary because they obtain their required energy directly from the overhead line.