This train running from Chicago to Seattle is the busiest passenger train in America. The route passes through America's longest tunnel where Matt finds out how the railroad keeps passengers from choking to death and how to keep the tracks from flooding. In the Cascade Mountains he learns what it takes to the keep the rails clear of snow drifts over a dozen feet high! This episode covers how James J. Hill built the Great Northern Railroad; and the Wellington avalanche disaster. It features some of America's most beautiful scenery in Montana's Glacier National Park.