The Chicago, Milwaukee, St. Paul and Pacific Railroad (commonly known as the Milwaukee Road) used the pass for its crossing of the Continental Divide on its mainline between Chicago, Illinois and the Pacific Northwest. The line was built as part of the Milwaukee Road's Pacific Extension, which was completed in 1909. The railroad line cut under the pass via the 2,290 ft Pipestone Pass Tunnel at an elevation of 6,347 ft (1,935 m). The line was electrified in 1915 and served the Milwaukee Road's premium transcontinental passenger train, the Olympian (later the Olympian Hiawatha). A poor competitive position against the rival Burlington Northern Railroad and substantial losses caused the Milwaukee Road to abandon the line in 1980.