Help - Engine quit

[Rcrain3]

I have a small HO oval set, probably from the late 1980s. Rarely used. Set up around the Christmas tree. Engine is an EMD GP40 Diesel. It was running this afternoon for a few minutes and then it just stopped. Checked everything. Wiring correct. Engine on the rails. Light comes on in the engine with a buzzing but the engine doesn't even try to move. What to do?

[jward]

can you move the wheels by hand?

[Rcrain3]

Yes. Some resistance but they roll.

[rbturner]

What comes to mind for me is the poor solder joints on that era of loco. Check to see it a wire came off at the side of one of the trucks.

[Rcrain3]

I took the engine apart this morning and found a broken gear in the motor assembly. Just bought another engine from eBay.

Thanks for the help.