I don't always want to run a second car behind, and the only trailer I would use for that, is a trailer that I already bought the trucks for. I was looking at a k-line locomotive I have, and I noticed the worm gear has the same gear spacing as Lionel, so I think I will purchase a k-line replacement worm gear, and mount the motor vertically. I would have enough room for the motor inside the hole in the floor. I would have to then make an arm attachment from the top of the truck around the king pin, and up inside, enable to hold the motor. Doing that, I would power the motor car like every other, and I would have not compromised any detail.
What do you guy think? Is there any problems you guys could see?