A trolleybus is essentially an electric bus that gets its power from overhead wires, a “trackless trolley”. As it doesn’t run on rails, a second trolley pole is needed to return the current. It was very popular in hilly cities or cities where electricity was more readily available than gasoline. Trolleybuses never broke through in Brussels. The system only consisted of a single, experimental line, built in 1939 between Forest and Machelen. The line contained a number of steep hills, narrow streets and large avenues. The experiment ended in 1964 when the vehicles had reached their age limit.
