|LEGO → System → Trains → 12V|
|7865 Motor Replacement Unit for Battery or Motor-Less Trains 12V|
The unit incorporates six wheels, with the four outboard wheels being driven by the motor through a worm wheel drive. Power is collected from the conductor rails through spring loaded copper pick-up shoes - two at either end to allow the train to negotiate points without power interruption.
A power-take off socket exists at both ends to allow the unit to power on-train lights.
After heavy use, the nylon worm gear inside the motor can wear out.