third rail
1 of 1noun/ˈθɝd ˌreɪl/
Forms:third rails
1
an additional rail providing electric power to trains, often used in subway systems
A third rail is an additional rail, placed beside the regular tracks, that supplies electrical power to trains. Instead of using overhead wires, trains draw power from the third rail through a special device called a shoe, which touches the rail and transfers electricity. This system is commonly used in subways, urban transit, and other rail systems where overhead wires might not be practical. The third rail is typically located close to the ground and is carefully insulated for safety to prevent accidents.
- The subway train drew power from the third rail.
- They installed a new third rail for the metro extension.
- The third rail ran alongside the regular tracks.
- The third rail system improved train efficiency.
- She was warned to stay clear of the electrified third rail.