I recently bought an MTH Premier SD45 ( 20-20459-1). I turned it over to grease the gears and oil the pick-up rollers. While I was at it I thought I'd clean the metal wheels on the trucks using 91 per cent alcohol and a Q-tip. I turned the speed up to 15 smph and cleaned the metal wheels on one truck. I pushed down pretty hard with the Q-tip and the wheels continued turning with no problem. I started to clean the rollers on the other truck and I barely touched the wheel and it stopped. I had to speed it up to 35 smph in order to keep the wheels turning so I could clean them and I still couldn't press down too hard.
Don't the trucks have the same size motors, same gears and gear ratios so both trucks should receive the same amount of power? I'm just curious.