The most ambitous AFV project I ever undertook was the conversion of an Airfix 1:76 scale Churchill battle tank into a working Bridgelayer - here it is ready to lay a bridge over a supposedly dangerously cracked viaduct - more likely just playing a trick on his mates. After all those years (decades) it's amazing the mechanics are still in working condition although there is a white tell-tale of polystyrene where a bearing has come astray.
The bridge is now raised, the bottom end of the mechanism becomes joined to the tank.
The centre set of bearings become unjoined and the bridge is lowered into position
From above, showing the lowered bridge
The mechanism is retracted
Closeup - mechanism upright
Closeup - back in the home position