Reply to ccjersey:
TC,
How do they pull and steer under a load? I always wondered how a differential steer tractor worked, or is the new Caterpillars' system I heard about something different from the Track Marshal brake and differential system.
Track Marshall's were built at Gainsbough England, they were great little tractors, wide spread with a good pull, the Perkins motor was always very under stressed, in this tractor poking out 70 hp hence the TM 70, this engine is good for about 120 hp, the diff steer thing is not to far away from the CAT system , I would think its true lines is from the battle tanks from WW1-2, in the final drive there is a brake drum with an external contracting band, the same as on a CAT, but this is in the F/drive , this slows down the shaft when braked ,making the differental speed up on the other side ,so as to effect a turn , both tracks are constantly driven as there is no steering clutches, I have stacks of pic's of these old bangers ripped to bits, some even with CAT bits stuck on them, I can always post a few if you like,
tctractors