Here is the science behind this trick:The black line you see when you rub your finger across a dirty track is made up of nickel oxide, dust & other contaminants. When electricity is applied it causes the dirt to 'float' (probably more like vibrate) on top of the nickel oxide where it contacts the wheels, causing them to momentarily lose connection to the track. This is why you see head- light flickering, loss of power, etc. We all know dirt is not conductive, but here's the kicker...neither is automatic transmission fluid. However, nickel oxide IS! The ATF reacts with dust making it heavier than the nickel oxide, allowing the train to maintain contact. This also answers the question, what happens to the dirt? The answer is...nothing. It builds up on the track like it always does & sooner or later will need a good hand cleaning. But hey, if the ATF delays that process for a while I say go for it!