I just bought a brand new Spectrum HO scale 4 8 2 and it makes a vibrating sound sometimes when it is being reversed down a length of track. The unit is being operated in the DC mode. The unit can crawl quite slowly and sometimes when I back the throttle off slightly the sound if it has occurred will stop. It is difficult to locate the source of the sound but I think it is in the boiler area and not the tender.Any suggestions for help would be appreciated.
Because it’s new, I would exchange it at the dealer. Also, Bachmann’s life time warantee is very good. I have the Spectrum heavy mountain, and do not have the problem you described.