Thanks Steve and everyone else who has helped me so far. I truly appreciate it!
I tested the loco w the shell off. Turned smoke switch off, reinstalled linkages. Not seeing any sparks, but I still hear the hum when I give the track power. I still have to check the front bulb.
I found that part of the wire insulation for the small rear wheels is damaged near the soldered point inside the loco and a small amount of the inner wire is protruding and looks to be cut. I will try to cut that part out and resolder to see if that helps. I did have the rear wheels off quite a bit when replacing the front drive axle, so maybe with all the movement and strain on the wire it could have caused that.
