Once there was a pioneer road that would (almost, or sometimes) hold up a truck there where civilian trucks hauling for commercial enterprises, trading posts and the army.
Both the US Army and the several civilian contractors who followed them used similar equipment so the Cat in this picture could be from either source. However, since there doesn't appear to be very many stumps in the trail I suspect this one is civilian.
Mechanics from the 93rd Engineers, 1942
341st Engineers on a structure they undoubtedly built and ...
... what it looks like driving over such a structure.
This depicts early attempts at civilian travel in 1943.
A great many things have changed since '43 such as the pavement that can be seen between the snow banks from this picture of Km 1639 taken on Feb.26, 2013. Something that hasn't changed is the marvelous scenery; that is the St. Elias Mountains in the background.