Base

Here is the base, after dismantling the tracks, the bearing support and the underneath casing, revealing the mechanisms.

The motor runs continuously. It's saved from an electric screwdriver, has a built-in reduction train, and gives a really impressive torque.

The weight of the model lies, on each side, on an articulated train of four pairs of 25mm wheels with tyres. The upper part of each track is supported by two other pairs of wheels (with rubber rings), and is tensionned by the rear idle guide (left on the picture).