I seem to have a problem in an auto. reverse section of my track. It's usually 1 engine (Genesis F3 AB lashup) When the engine is in that section it starts & stops & the polarity LEDS flash indicating that the polarity is constantly changing. If I run it thru that section fast everything is OK. Only have the same problem with another engine very infrequently. Seems to run better if the track in that area is kept Extremely clean. Any Suggestions?? Thanks.... Jerry