I just put together a quick oval on the floor in the guest room to run an engine. I have about 40 feet of brass Atlas (83), Playart, and IHC track. The engine is real herky jerky and runs good on some sections and not on others. I read up on the problem and it sounds like dirty track. Just wiping the rail with my finger I get a sooty film. I am going to the hobby shop later this week (once the blizzard shuts down) to see if he has any of those track cleaning pads.