The kit is designed for 2 different motors. I've got the Maxon (similar to Faulhaber) coreless motor as it was offered with the kit.
In years past I enjoyed taking my N gauge locos apart and watching the motor with the wires on the core spinning around between the magnets. As I understand it, a coreless motor has a magnet in the centre and a coil of wire spins around it. I'd like to open it up and have a look, but at £30 a time I can't really afford it. The ones I've seen in action appear to be beautiful slow runners - perfect for a shunter.
The bearings support the motor at one end and the shaft at the other.
First attempt - the motor bearing isn't flat against the mount, and the joint has started to come apart.
I fold the end down, file away some of the side, correct the soldering and fold back up.