Courtesy of the National Film Board:

This is a short documentary about winter railroading in the Canadian Rockies and the men who keep the lines clear. The stretch between Revelstoke and Field, British Columbia, is a snow-choked threat to communications. The film shows the work of section hands, maintenance men, train crews and telegraph operators. 

I thought it was a pretty good and informative video. Hopefully others can watch it, as I don’t know if NFB videos are region locked.