The front bracket holds both the front axel and the slot for the track. It is held in place using two M3 screws which fit into the holes at the top.
The back bracket holds the motor assembly together with the back axel. Here three M3 screws tightly secure both parts together.
Both axels are housed in brass casings which act as bearings. The axels are approximately spaced 70mm apart.
Between the front and back sections of the chassis there is a hole which is designed to receive a screw on bolt to hold the body shell in place.
The model was created using the new Fusion 360 CAD software by Autodesk which is currently in Beta but will be released soon.