I just picked up a new Atlas SD-35 on the 'bay to replace the mechanism in 7436, which is about kaput after almost 7 years of faithful (and heavy) service. This one was the only one out 7 of these things I own that got the high-pitched gear whine. The motor is still serviceable, but I was just never able to get the drive train to smooth out for some reason. So into the parts bin it will go, it's "brain" being transplanted into the new one once it arrives.
The shell is painted by me, and will be transfered to the new drive also. The incoming unit is a first release WM Circus with an un-numbered cab. The cab will be numbered for 7435, and transplanted onto that unit, which was damaged in a previous gravity experiment. So I'll be able to restore two locomotives to full operation and appearance for the modest investment of $45!
When I had to can a couple of Bachmann drives, it was no big deal. But when you have to retire an Atlas Drive, its a sure sign you're getting older! :'(
Lee