A thir rail is a method of providing electricity to power a railway through a continuous rigid conductor alongside the railway track or between the rails. It is used typically in a mass transit or rapid transit system, which has alignments in own corridors, fully or almost fully segregated from the outside environment. A list of lines or networks equipped with a third rail is provided further below. Third rail systems generally supply direct current to power the trains. In the early 1900s the third rail system was used to power early rollercoasters such as the Rough Riders (rollercoaster) in Coney Island, New York.