D&RGW use of bulldozers for snowfighting

The Kettle Valley Railway (KVR) was a standard gauge transcontinental line that crossed southern British Columbia. One segment called Coquihalla Pass was essentially a drill hole along the length of a serpentine mountain gorge, comprised of a chain of short tunnels and enormous trestles. During some years, snowpack was said to have reached a depth of 30-40 feet. For most of the life of this road, two plows were used, a wedge and a rotary. Bulldozers came later.

In his book McCulloch’s Wonder, Barrie Sanford states, “the bulldozers were so superior at snowfighting that early in the 1950’s the CPR removed all but five of its original sixteen snowsheds [along the KVR]”. They used up to 14 bulldozers at once to do the job of the two plows.

I am curious why the D&RGW stuck with rotaries for clearing the deep snows of Cumbres or Marshall Pass after WWII when there were plenty of bulldozers around. I don’t recall seeing photos of an army of bulldozers at work in these places.