Conductor (rail)

A conductor (American and Canadian English) or guard (Commonwealth English) is a train crew member responsible for operational and safety duties that do not involve actual operation of the train. The conductor title is most common in North American railway operations, but the role is common worldwide under various job titles. Conductor job responsibilities typically include:

Some rapid transit systems employ conductors to make announcements and open and close doors—as opposed to a train operator performing those duties. The conductor often stays in the center of the train where they can best view the platform. While advances in automation allow most transit systems to use one person train operation (OPTO), a few, such as the New York City Subway and Toronto Transit Commission, continue to employ conductors.

Third rail

A third rail is a method of providing electric power to a railway 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 always supplied from direct current electricity.

The third-rail system of electrification is unrelated to the third rail used in dual-gauge railways.

Description

Third-rail systems are a means of providing electric traction power to trains, and they use an additional rail (called a "conductor rail") for the purpose. On most systems, the conductor rail is placed on the sleeper ends outside the running rails, but in some cases a central conductor rail is used. The conductor rail is supported on ceramic insulators (known as "pots") or insulated brackets, typically at intervals of around 10 feet (3 metres).

The trains have metal contact blocks called shoes (or contact shoes or pickup shoes) which make contact with the conductor rail. The traction current is returned to the generating station through the running rails. The conductor rail is usually made of high conductivity steel, and the running rails are electrically connected using wire bonds or other devices, to minimize resistance in the electric circuit. Contact shoes can be positioned below, above, or beside the third rail, depending on the type of third rail used; these third rails are referred to as bottom-contact, top-contact, or side-contact, respectively.