pantograph

The diamond-shaped, electric-rod pantograph of the Swiss cogwheel locomotive of the Schynige Platte railway in Schynige Platte, built in 1911 Cross-arm pantograph of a Toshiba EMU A pantograph (or "pan" or "panto") is an apparatus mounted on the roof of an electric train, tram or battery electric buses to collect power through contact with an overhead line. The term stems from the resemblance of some styles to the mechanical pantographs used for copying handwriting and drawings.

The pantograph is a common type of current collector; typically, a single or double wire is used, with the return current running through the rails. Other types of current collectors include the bow collector and the trolley pole.