The Chicago, Milwaukee, St. Paul and Pacific Railroad (the Milwaukee Road) completed a line through Snoqualmie Pass in 1909, part of its Pacific Extension. This grade was soon replaced in 1914 by the 2¼-mile (3.6 km) Snoqualmie Tunnel, from Hyak due west to Rockdale, at an approximate elevation of , more than below the pass. The rail line was abandoned in 1980, and the tunnel is presently a multi-use trail for bicyclists and hikers, part of Iron Horse State Park. During tunnel construction, an improved wagon road was built over the pass. Near the original rail line, the Sunset Highway was opened through the pass in 1915.