GP9?

Its a Red Caboose GP9. I hope you didn't pay 3rd rail money for it. Unscrew the couplers, then grab the sideskirts above the fuel tank and spread the shell slightly. The shell will lift off. Its a horizontal drive with a pittman motor driving both trucks.

P&D Hobby Shop and Des Plaines Hobbies would be the place to go for parts, but the original drive is a 1970's era Atlas/Roco drive.  NWSL makes new 2 rail wheelsets for them, I dont know about 3 rail wheelsets.  They're known for stripping the axle gears loose from the axle, but aside from that, if you dont try to pull huge trains with them they are pretty reliable drives,

Thanks for the Info. I probably gave too much for it but not 3rd Rail prices. I gave $225 which I looked on ebay for Red Caboose and discovered it still wasn't a bad deal as a lot of Ebay sellers want $300+. The ones for less were in a lot worse shape than mine.

I think you are aware of this now, but you should never buy an item without seeing what’s actually inside the box.

Regardless, it is a nice looking Geep.  It even has the correct front headlight for an NKP model.