Rockslide

S1, E5: Ferocious weather and treacherous terrain won't stop Canada's freight and passenger trains from rolling during the winter. That's because the crews profiled in this series do whatever is necessary to keep the historic Canadian Pacific Railroad running from coast to coast. With a fleet of 500 locomotives and cars and an arsenal of innovative snow fighting machines, its operations are critical to the country's economy. Shutting down is not an option, despite constant threats of deadly avalanches, monster icicles, rockslides and dangerous wildlife. In the coldest frostbitten months, the network stands up as a feat of modern engineering.