@Lou1985 posted:The intermediate gear is probably how Lionel gets the gear train to be backdriveable. The old K-Line gearbox setup is not backdriveable at all.
There are plenty of Legacy locos with back drivable gearboxes with the traditional worm and axle gear setup. I suspect the extra gears are to allow better low speed performance or get the best performance out of the motor/speed control being used in a particular loco.