Time for some big HO news!
I have had trouble for years with my Bachman HO locomotives needing constant cleaning to run smoothly. Like many enthusiasts I use rubbing alcohol on the tracks and loco wheels. Dave (djacobsen) told me that I need to get contact cleaner, which I found in an electronics shop.
It works great! The immediate improvement was noticeable. Be careful not to let it into your eyes, as it is a fine mist that bounces off the wheels.
PS. Dave, you're a genius!