Tracked Vehicle in Escape Scene

It's actually of WWII vintage, I don't know the nomenclature but it was called the Weasel and originally designed for Arctic combat

M29 Weasel, built by Studebaker. As mentioned above it was originally intended for use in the snow but handled swamps nicely too. The Marines used them on Okinawa and the French used them in the Mekong Delta. There were even amphibious versions driven onto the beaches at Normandy.

By the time of this film it was obsolete. Really there should have been a different vehicle in place for Mutt to steal.

http://thumbs.ebaystatic.com/images/g/L4AAAOSwo4pYJdRX/s-l225.jpg