To play the Devil's advocate on this one..... I have two of the bachmann 0-6-0's and, considering the price, they're really not bad running critters, a little on the fast side. What gives them an "edge" is that besides pick-up on the loco wheels, they also pick up electricity from the lead truck on the tender. I have ordered a newer version as I have heard it runs even better than the old. Whether or not it has a new motor remains to be seen. Bachmann redesigned the 4-8-4 and did a nice job of it: split frame, new motor, better pick-up, and blackened wheels and rods. Even the boiler casting seems a little "crisper". The new 0-6-0 appears to have the new blackened wheels and rods but, I will have to wait 'til my new one comes to determine if anything else is "new" about it. I have not heard if the 2-6-2 has also undergone changes.
Dick