Need help with my train

Have a LLgp38 took the shell off to oil the gears.Put the shell back on runs very erractic runs a bit ok at slow speed.Also with this engine the track shorts at two places 180 degrees, My other 6 engine have no problem at all on this track…I check no access oil. ANY HELP WOULD BE APPRECIATED thanks.
Pat

DC or DCC ? I’d start by cleaning the wheels first with rubbing alcohol. My guess is you got oil on the wheels. If that doesn’t fix it, try running it without the shell. If that works then you have something rubbing the drive mechanism when you put the shell back on.

Thanks Engineer Jeff,
Clean wheels,didn’t help much.Runs great with out the shell. Took my time putting shell back on this time I heard the shell snapping in place.it runs like a train again. Thanks for your esperience Jeff. You kept it out of the junk bos.
Par