I have recently aquired a Bachmann HO train set(s),they look to be older..I am guessing at the Diesel type....the diesel in question seems to have some kind of short in it..when placed on the track it does not run..lifting the rear truck off the track while keeping the front truck on the track and the diesel will run...place the rear truck back on the track and there are a few sparks from the rear truck and the engine will no longer run....HELP..I don't know a thing about the HO guage..since I collect the O and G scales

I am looking for the tender for a Bachmann 4-6-0 and a new gear box for this engine....I don't know the model as I purchased it at a garage sale...it is a 4-6-0 older model with a two pin connection for the tender and a switch next to this connector for the on-off function to the speaker just below the boiler unit..also need a gear box for this engine...as it seems the worm gear on the motor has worm out the white plastic gears