Changes

A '''third rail''' is the [[railway track|rail]] of a three-rail [[railway electrification|electrified railway]] line separate to the two rails (the running rails) which carry trains, that carries the current to power the trains.

A '''third rail''' is the [[railway track|rail]] of a three-rail [[electric railway]] line separate to the two rails (the running rails) which carry trains, that carries the current to power the trains.

Electric trains on such a system have a "shoe" that contacts the third rail to collect the current, which is returned in the two running rails.

Electric trains on such a system have a "shoe" that contacts the third rail to collect the current, which is returned in the two running rails.

Some [[railway]]s have a fourth rail for the return of the current.

Some [[railway]]s have a fourth rail for the return of the current.