Awesome stuff - PITA to drive though cos by the look of it and the description the driver has to raise and lower the arms individually to keep them grounded.
When I was a young lad in the RAF the local forestry commission around Wendover had a series Landy which had been modified so that it had hydraulic motors on each wheel, so all the engine was doing was supplying pressure for the hydraulics....but nothing could stop it, and I mean nothing.