During Canadian Pacific Railway's spring repair season, Jordy and Tom's 119-car grain train faces a series of obstacles as it journeys through the mountains towards Vancouver. Crew boss Bruce and his team wrestle kilometer-long links of continuous welded replacement rail into place. A repair crew hustles to clear a paralyzed locomotive that's blocking the main line's single track. Machine operator Amanda supervises rookie Keri as a 15-machine convoy installs new ties. Meanwhile in Ontario, the Polar Bear Express shuttles powwow drummers-and kittens-south to Cochrane. It's an exclusive journey through the icy mountain wilderness on the country's most extreme railway. Shutting down is not an option, and it's in the coldest frostbitten months that the network stands up as a feat of modern engineering.