This is the second version of my "Wall Train".
First version had four motors. This version uses only one motor. The locomotive is four wheel drive.
One micro gear motor is used to drive a set of 3d printed gears, that move all four wheels, and the motor has to provide enough power to overcome gravity.
The wheels are designed to maximize friction and grip, and this is accomplished by their grooved shape and rubber coating.
The train is magnetically attracted to the base plate by magnets. The green base tracks are made of 1.5mm steel, cut with a laser cutter and painted with spray paint. The rail tracks are just made out of plastic, and glued on top of steel cut parts.