A trolley car is a vehicle which is used primarily for passenger transport in an urban area. Trolleys run on rails which are inset into the street, connecting to overhead electric lines for a source of power. They may also be known as streetcars or trams, depending on the region. Trolleys are technically part of the family of rail technology known as light rail. They may be referred to as trains when they are run on tracks which are separated from the roadway.
The development of the trolley car dates to the 1800s, when many cities began seeking out modes of public transportation. Public transport was designed in part to reduce congestion by providing people with a way to get around without private vehicles, and it was also used to make transport more accessible to people of low income, by providing them with a cheap means of transportation. Many cities began installing a variety of street cars, and the trolley car design quickly became popular.
By keeping the electrical wires overhead, operators could reduce the risk to the general public by making it hard for people to come into contact with the electrical wires, while still providing trolleys with a source of cheap, accessible power which also happened to be nonpolluting. The term “trolley” appears to have originated in reference to the device which connected with the overhead wires, and seems to originate in the United States. The related term “trolley bus” refers to a bus which powers itself with overhead wires, but which runs with tires on the pavement, rather than on tracks like a true trolley car.
Over time, the trolley car system became less popular because it was viewed as a congestion liability. More cars, trucks, and buses on the streets competed with trolley cars for space, and many cities began turning to dedicated light rail systems which ran on their own separate tracks, or to buses as a means of transportation. Eventually, the tendency to block traffic actually came to be viewed as a benefit which could be used to control congestion, and some cities reinstalled the trolley systems they had ripped out.
Several organizations refurbish and preserve historic trolley cars. These are put into service in cities around the world as objects of historical interest. In addition, cities utilize newly built modern trolley cars on their trolley lines. Fares to ride a trolley vary, depending on the region, and it is often possible to ride with a transit pass.