i got unopened 1st run sets off of ebay (paid WAAAAAY too much! :^0 ;^)) a while back and i found the running performance to be rather herky, jerky, with thomas being the worse offender…i found the wheels getting exceptionally dirty exceptionally fast…long story short, i found that replacing the lionel stock springs and brushes that contact the back of the wheels on the front and rear axels, with USA Trains brand springs and contact brushes, that both engines ran extremely better!!! lterally smooth as silk!!! wheel cleaning frequency, has been reduced by aproximately 1/3…to diminish the frequency, even further, George Schreyer has a method for adding pick-ups to the center wheels on his website…