I have a Lionel 1684 that occasionally shorted while running. I disassembled the loco and found that the aft sliding shoe pickup was shorting against the frame. I put a piece of electrical tape between the sliding shoes and the frame to prevent shorts.
There was no insulator in my loco and I cannot find a parts break-down on the engine to see if an insulator is supposed to be there. Olsen’s Toys had a limited parts break-down , but it was not detailed enough to determine if there should be an insulator.
Is there supposed to be an insulator between the pickups and the frame?
Earl