Keeping Canada's railroads running through the harsh winter is no easy task. In the 19th century, crews of up to 1,000 men with shovels were used to clear snow off the tracks. The development of the wedge plow in the 1880s meant machinery could take over this gruelling task. The shape of the plow proved so effective that the design is largely unchanged to this day. Tune in to all new Rocky Mountain Railroad on Thursdays at 8pm on National Geographic UK. | National Geographic UK