One problem with this type of system is what I believe is called
recirculating horsepower. Although the engine might be able to provide
500hp to move the vehicle along, the actual tranmission may have to be
able to transmit 2000hp for instance. IIRC this situation arrises due to
the load on the tracks when steering.

Clark Magnuson wrote:

Many years ago, the final drive for the M55, a 50 ton 500 horse power
tracked vehicle, was redesigned and still failed.
The cross drive transmission has splines that drive the pinions that
drive bull gears that are on the same shaft as the sprockets that
drive the tracks.
An old man wants to know if there are now pre twisted spur gear
pinions so, when highly loaded, a gear will be twisted straight.
TIA