So I just now took a couple of pics of my Red one, as you can see the wheels are not quite the same as Playmofire’s ones but certainly not the quality plated ones on the latest Piko offerings.
Looking inside you can see the two bars that go up to contact the motor and are where the single plugs are attached to get wire to a circuit board (if present) The centre holes next to them are where the other two bars that do track contact go. These can be jumped together in pairs (track/motor track/motor) to do away with any failed internal board but still keeps things running. The flat bars, plungers and skates have all been removed for this battery conversion. Hope this helps a little. Other thing of note is the difference of gear colours, mine being grey and that is not the gunk contained in there! I have duplicated these words in my Red Loco Build to make things complete.
Other thing of note is the difference of gear colours, mine being grey and that is not the gunk contained in there!