DART Rail Institute Definitions Practice Exam

A pantograph is the device mounted on the roof of an electric train that maintains contact with the overhead electrical line to draw power for propulsion. As the train moves, the pantograph presses a contact surface against the overhead catenary, with springs and a lightweight, rigid arm keeping a consistent connection so electricity can flow into the train’s traction equipment. This setup allows the train to receive the energy it needs to run, with the pantograph designed to rise and lower as needed and to cope with changes in height, weather, and speed. The other options don’t fit because a brake shoe is used to slow the train by pressing on a wheel or rotor, not to collect power; a wheel used for mechanical coupling is part of the train’s coupling system, not electrical power collection; and a device to tether the train to the track isn’t how trains are powered and isn’t a standard traction component.