Hi,
IIRC, the C&TS is also a historical civil engineering site because it shows 1880's construction methods. Most of the track located on south facing slopes so nature could melt the snow or keep accumulations down with respect to the north facing (shadowed) slopes.
I wonder if Monarch Pass would have had a good westbound slope on preferred mountains or if it might have had considerable north slope alignments.
Off the top of my head, the main north slope locations are in the Narrows, near Coxo, a short section just west of Sublette and at Big Horn (which I recall as more as a ridge top and not a mountain side)
Doug vV