It’s actually pretty simple, T-26 uses angular motors on levers of suspension (arched parts to which bogies with wheels are connected).
Regarding drive train, I’ve uploaded new version with a locked differential last week. Added sound for shifting gear too. Still need to clean up code and add open differential and add rolling friction for tracks.
Commander mode can be added on top of such system. Need to decide on some sort of component and interface which will handle input from keyboard/mouse/gamepad and an automatic mode on top of it. Right now input code is handled in pawn, which is not good for modularity.