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Tram

Public transport vehicle running on rails predominantly located on streets

A tram (also known as a tramcar, or a streetcar or trolley in Canada and the United States) is an urban rail transit type in which vehicles, whether individual railcars or multiple-unit trains, run on tramway tracks laid on public streets, although some trams run on sections of track in their own segregated right-of-way. Trams are a type of light rail and are included within this broader category. However, they differ from it in their frequent integration into urban streets, lower traffic signal priority, coexistence with other vehicles, and lower capacity. Their units are capable of forming motor coaches or motorcars, which allows for the operation of longer trains. Trams are usually lighter and shorter than main line and rapid transit trains. Most trams use electrical power, usually fed by a pantograph sliding on an overhead line; older systems may use a trolley pole or a bow collector. In some cases, a contact shoe on a third rail is used. If necessary, they may have dual power systems—electricity in city streets and diesel in more rural environments. Occasionally, trams also carry freight. Tramlines or tram networks operated as public transport are called tramways, streetcars or simply trams, including systems separated from other traffic. Some trams, known as tram-trains, may have segments that run on mainline railway tracks, similar to interurban systems. The differences between these modes of rail transport are often indistinct, and systems may combine multiple features. One of the advantages over earlier forms of transit was the low rolling resistance of metal wheels on steel rails, allowing the trams to haul a greater load for a given effort. Another factor which contributed to the rise of trams was the high total cost of ownership of horses. Electric trams largely replaced animal power in the late 19th and early 20th centuries. Improvements in other vehicles such as buses led to the decline of trams in the early to mid 20th century. However, trams have seen a resurgence since the 1980s.