I found out what was wrong and corrected it. I must have gotten a Friday locomotive. The pickups in the trucks were so badly placed that they were making intermittent contact and in some cases were shorting out. I fixed that problem in about 30 minutes. The soldering was very badly done. The wires on the trucks were so poorly soldered that they would come loose with just a gentle tug. 5 minutes of soldering fixed that. Here's the biggie. The motor is faulty. I'm not sure what's wrong with it, but it won't hold a steady RPM. I changed it out with the motor from a John Deere BB F7. The locomotive runs fine now on DC and DCC, no humming, no growling (except a little from the BB motor). The growl sounds quite a bit like a diesel engine. These are problems I would expect to find in a BB locomotive, not a $110 RTR that's supposed to represent quality. If this had been a Proto 2000, Walther's would have gotten it back with a strong letter of complaint.
With all this repair work, it has earned itself the title of 'Honorary Tyco Locomotive'.
With all this repair work, it has earned itself the title of 'Honorary Tyco Locomotive'.