Current Collecter

Electric current collectors are used by trolleybuses, trams, electric locomotives or EMUs to carry electrical power from overhead lines or electrical third rails to the electrical equipment of the vehicles. Those for overhead wires are roof-mounted devices, those for third rails are mounted on the bogies.
Typically, they have one or more spring-loaded arms that press a collector or contact shoe against the rail or overhead wire. As the vehicle moves, the contact shoe slides along the wire or rail to draw the electricity needed to run the vehicle’s motor.