Back in '73 I was working at the Navajo generating station in Page Az. and we had a rotor that had to be trucked from flagstaff to page and It was not allowed to get on the roads because it was so big and heavy. about the same size as this thing but solid steel. I was an operator on one of the 4 D-9 dozers that had to help push this thing across the dessert sands. I used to have a video of it but thats long gone now.
now that is a story.
the D9 was used in the movie Killdozer! a 1974 made for TV science-fiction horror movie,
and I tend to remember the two dozers were D9s used in Vanishing Point.