Well, I can't seem to isolate the problem so I sent it back to the manufacturer. Other than this issue the locomotive runs beautifully and at nice, slow speeds. I am looking forward to getting it back and putting it to work.
I'm an old DC guy and continue to do that too as an extension from my early days in N Scale when it was almost a necessity. Plus, it just looks cool and can sometimes sound cool too.
BIG kudos to Bachmann. I sent the locomotive in for repairs. They shipped me a brand new one and it arrived within seven days of the time I shipping the defective unit back. Awesome customer service. The other area I have to give kudos to is the locomotive itself. My entire fleet (approx 50 units) are all Kato, Atlas, BLI, and Intermountain. I don't run a lot of steam (except the GS4) and other than their steamers I've never considered Bachmann to be in the same arena as the other mfg's I mentioned. But this little S4 IS on par with them. Is it 100% on par with Kato? Doubtful since I haven't (in my opinion) found anyone at Kato's level, but it certainly is with everyone else as far as detail, quality, and slow speed running. Needless to say, I am VERY happy with Bachmann right now and hope they do more models of this caliber. If you are looking for a switcher I would highly recommend giving these S4's a look. At the price point (I paid $65) they are difficult to beat.