Thanks! Yes, these are the same locos. I don't understand how that wiring arrangement works, but I assume that the front drawbar wire is isolated from the one on the back.
My new motor fits fine and I'm figuring out the universal shaft connection. Are you able to send a good photo of yours? It looks like a plastic tube with a pin through the shaft at both ends. Mine seems home-made. I hope to make this better. Getting closer. These are very nice looking locomotives IMO.