|Contactor plate for accessories. A mainstay for Lionel operation. This single-pole, double-throw weight-activated switch was developed for the 153 Block Signal in 1940. The 153C acted as a switch between terimals, but eventually was used as an on/off weight activated switch for numerous accessories(45 Gateman, 152/252 Xing Gate, and more). Can be used today with most accessories.