 It was a derivative of their Trado conversion to produce a 6×4 off-road truck from a commercial 4×2 chassis.The Trado used a bogie rear suspension for both sets of rear wheels.This suspension, best known through the Scammell Pioneer of 1927, uses a single central axle, or driveshaft, that in turn drives two "walking beams" ("balanceur", in Dutch) one on each side.