Ok - I went to the Train Show today & picked this up for a Ten Spot. I think it's a Traction Brake Control. It's now a switching machine on my G Scale layout. If anyone knows what it is, let me know. The guy said it was from an MU car on The Reading RR in PA. It's from a doctors collection. He had someone in his family that worked on the RR & he would bring the doctor (who was also into model RRing) stuff to store / collect for him.