The RF&P train that you mentioned could have had it's headlight and control circuits powered through the MU jumper. As for GG-1, E-44/33, and steam throttle combos,, another one to add another throttle type mix is the Baldwin style throttle. Some BLW ( and a few FM's ) units were equipped universal MU's that had an infinitely variable throttle. It had no notches, just a wire wound resistor that was tied to the governor to control engine speed. Someone had to figure out how to get that to work 8 and 22 notch throttles.
And don't worry GEC,,,, Some of those F unit parts will live on in Scranton.
And don't worry GEC,,,, Some of those F unit parts will live on in Scranton.
My other car is a locomotive, ARHS restoration crew