Track and Motorised Thomas Mini's?

Just to keep you up to date, I've found and ordered a micro motor, it measures 6mm x 12mm so should fit with ease. I've also got a pair of brass gears in the form of a pinion and worm gear. When they arrive I'll have a look at how its best to mount them on a mini chassis and how much needs to be trimmed off a mini body to get it on successfully. Then I just have to worry about a power source