In 1890, Great Northern assigned the task of finding a railroad pass through the Cascades to John Stevens. After some months of surveying, crews began working westward from Spokane, building bridges as well as laying rails. The workers labored in almost complete isolation, through dangerous terrain. Though Scenic and Wellington were only four miles apart, the switchbacks required to rise up the mountain covered twelve miles of track, and as the work progressed, they realized that a tunnel would ultimately be required to eliminate traversing the four percent grade.
In January of 1893, the track was completed. Costs of keeping this line open were high, and in 1896 plans were made to construct a tunnel and eliminate the switchbacks through Wellington. Hundreds of men began work the next August working with primitive tunneling tools, and by September 23, 1900 this tunnel was bored through. In spite of the lack of technology, the east and west end of the tunnels met within one half of an inch on a tunnel that was 2-1/2 miles long. The new tunnel saved 8.54 miles of track and 2,332 degrees of curvature. On December 10, 1900, this tunnel opened for traffic.
In spite of this achievement, the rail line was plagued with delays due to heavy snow in the winters. This tunnel served its purpose until a new tunnel was built in 1928, the 7.79 mile new Cascade tunnel still in use today. The new Cascade Tunnel would shorten the route across the Cascades by 8.9 miles, and eliminate seven miles of snowsheds and 3,674 degrees of track curvature.