There were some serious problems with the first runs of this engine, like the sloppy soldering jobs shown on the sides of the frame. Call Bachmann and let them know it won't run correctly. They'll give you a return authorization number. Send it off with $20 and you get a brand new 44 tonner, with dual motors and a better decoder. You don't have to be the original owner or have a receipt. Bachmann has a lifetime guarantee, no matter where it came from. You have to get it back together though, since any signs of customer abuse or tampering voids the warranty.
Questions about fixing Bachmann engines seem to come up all the time. Well-meaning members will come up with all kinds of suggestions, but many of the things suggested will void your warranty. If you have a problem with a Bachmann engine, send it back and let them fix or replace it. The more time you spend fooling around with it, the more likely they'll attribute the problem to customer abuse.