I was thinking about the Mars XL tank.

[The_Caveman]

Hang on - tracked vehicles roll on wheels which sit on tracks.  I can't see how this could be done without wheels?

You have the tread plates moved directly by linear induction motors mounted in the hull. Like a maglev train, except the vehicle is the "track" and the "train" is a loop of treads. Change your inertial frame of reference and you see that the tread plates which are in contact with the ground are stationary and the vehicle is what's moving, just like with a normal tank. The plates at the rear of the vehicle are lifted up and plates are laid down in front of the vehicle as it advances forward.

To reduce the sliding friction between the hull and plates you would need bearings, either roller/ball bearings or magnetic bearings.

Because the plates are not a belt held in tension by rolling wheels, they don't have to perfectly interlock, either. You can have each plate be individually articulated to the hull on its own bearings, so that if one is blown off the rest of the loop continues moving around the raceway.

Suspension would be accomplished by articulating the raceway itself on shock absorbers that sit between the raceway and the rest of the hull.

[Colt Ward]

Electric motors don't stall. They can direct-drive the wheels.

Or, as I suggested upthread, they could use linear motors to drive the tread plates directly and not have any wheels at all.

Not going to happen b/c how do you propose to fix that broken track in the middle of a muddy field?

[The_Caveman]

Not going to happen b/c how do you propose to fix that broken track in the middle of a muddy field?

Because every plate is individually driven with its own linkage, a break in the track shouldn't stop the vehicle from moving unless the damage is so severe that the raceway itself is ruined--which would be analogous to a damaged axle in a wheel-driven vehicle. You could blast half the plates off and still generate useful traction. Unlike a conventional track it doesn't depend on being held in tension for the vehicle to make progress.

Also, if the raceways are articulated separately from the hull, then the same mechanism should be able to be used to lift a seized track section off the ground so that the seized plates/raceway segment could be replaced. If the damage is too severe to do that, you probably have bigger problems anyway.