I recently bought the above Bachmann loco. I was warned by several people that the engine would constantly derail. I didn't believe them. Bachmann wouldn't sell something that was really defective. However on receiving and operating the engine I found the warnings were valid. The loco derails every few feet on 24" minmum radius track. All my other engines, 26 in all, have no problems whatever. There is obviously something wrong but inspection of wheel and driver alignment shows nothing.  Please advise.