The current collector supplies electric power on the move, when it is mounted on the subway, overhead traveling crane, or automatic conveyer line. The current collector should have high lubricating characteristics and conductivity, as well as high abrasion resistance and hardness, while not damaging the counterpart current supplying rail.

Ag-Gr and Cu-Gr materials are used as the contact point for communication device, DC relay, sliding device, and carbon for current collection, as these materials provide excellent seizure resistance and sliding characteristics. In particular, these materials are used as carbon for current collection, such as automatic conveyor aging brush and overhead traveling crane for subway.