For "pioneer" projects the D6 was and is handy tractor/dozer. This D6 has the LeTourneau cable blade setup. I have not as yet added the cable or pulley sheaves. Currently drying, a couple as drawbar tractors with winch but no blade.
They were designed as a heavy gun tractor in 1938 to haul a 5.5" artillery piece plus up to a 10 man support crew, kit and ammunition. they were still in service in the 1960's.An interesting vehicle, I have seen many photos of versions serving Imperial Troops. I think I remember seeing one in the ANZAC Day Parade in Sydney once upon a time. Interesting the wartime photo shows US markings but appears to be containing Imperial troops.
For 3D modeling such a vehicle (for my primitive software) is fairly straightforward as it's mostly geometric shapes and few irregular compound curves. The large tires are interesting, being a different approach than the 10 wheel configuration of the "Duce n half". I would guess the occupants didn't put up with much "Bull".
I missed some of the action here but did hire a man to build a logging road for me, he had a D-8 (which were very popular for land clearing) with the cable straight blade. He built a road in a day with beautiful ditches and a nice grade. The man was 80 years old in 1982 and grew up running the early dozers. I should have watched his method for getting nice ditches with the straight blade, but this was before hydraulics (it was an old D-8)Here is Main Street in Skagway during the war. Note the loading ramp. My guess is that there is a switch there and they load every flatcar one at a time on a 40' spur? A D6 similar to the one I made. Like the Dodge Command Cars! Notice the large chocks!View attachment 162481