Third rail

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A third rail, also known as a live rail, electric rail or conductor rail, is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a mass transit or rapid transit system, which has alignments in its own corridors, fully or almost fully segregated from the outside environment. Third-rail systems are usually supplied from direct current electricity.

Modern tram systems with street-running avoid the risk of electrocution by the exposed electric rail by implementing a segmented ground-level power supply, where each segment is electrified only while covered by a vehicle which is using its power.^[1]

The third-rail system of electrification is not related to the third rail used in dual-gauge railways.