There were two manufacturers of traction equipment for PCC cars, Westinghouse and GE. I understand they were quite different. The number you gave is a Westinghouse controller used on early PCC's as far as I know. There were many changes, and changed numbers, over the years. There is a a bench display of PCC-style control in Kenosha, shown at the link below. Not shown is the master controller, which was foot-pedal operated, much like an automobile. Chicago streetcars were the exception, with an odd handlebar-like system allowing operation with hands, not feet.
The drum style controller used on PCC's were typical, but I think the last order of car in Boston used a conventional cam controller with sepaarate resistance grids? And Chicago had hundreds of rapid transit cars with PCC control.