The Great Northern's Cascade Tunnel

The Great Northern's Cascade Tunnel, also known as Stevens Pass Tunnel, is actually the second structure to be built through the mountain, replacing the original in the late 1920s. At nearly eight miles in length it is easily the longest railroad tunnel ever built and remains in operation by successor BNSF Railway as part of its transcontinental main line which connects Seattle and Chicago. For roughly 25 years the tunnel was electrified by GN but this was discontinued in the mid-1950s. Due to the tunnel's length it has a rather problematic handicap, even today, of requiring ventilation of the shaft for up to 45 minutes. As a result the tunnel is somewhat of a bottleneck on the BNSF system.

Now that these railroads were all under one-control Hill quickly set about building to the Pacific Coast and Seattle which was accomplished just four years later in 1893. Throughout the rest of the early 20th century Hill worked to modernize his main line, especially through the Rockies by eliminating grades and curves. Before his death in 1916 he was able to achieve this with the most famous project along the line being the Cascade Tunnel through Washington’s Cascade Range (a new tunnel was later bored and opened in the 1920s, which is still used today by the BNSF Railway). The western main line through the Cascade Mountain range was also electrified for years (although it proved to be a troublesome and unreliable operation) until better ventilation and improved diesel locomotives allowed for its discontinuance in the late 1950s.

The original Cascade Tunnel built by the Great Northern began construction in the late summer of 1897 and took more than three years to complete, opening just before Christmas, 1900. While it still sat a very high elevation of nearly 3,400 feet it eliminated a hellish grouping of switchbacks originally required to scale Stevens Pass where not only were steep grades a constant problem but also unrelenting snowfalls that buried trains for days.

While the original 2.6-mile long tunnel improved railroad operations by reducing grades to between 1.7% and 2.2% it still sat high on the mountain, within range of punishing Cascade blizzards. With the avalanche disaster at Wellington, Washington on the first day of March, 1910 which killed 96 passengers near the entrance of the tunnel's west portal the GN was forced to find a better route over the mountain.

The extraordinary length forced the Great Northern to electrify the tunnel to avoid fumigation issues, which would have been caused by operating steam locomotives. However, the railroad constantly had trouble with its electrics, which had always seemed to have difficulty obtaining the correct voltage needed to power trains over the summit and through the tunnel (it has been said that the GN's electrified operations were never engineered correctly, resulting in these issues).

As it turns out fumigation problems haunted the railroad and its successor, Burlington Northern, not only because of the tunnel's length but also because of the grade it was built on, about 1.7% from west to east. The first ventilation systems took up to, if not more than an hour to clear the tunnel of diesel fumes before another train was allowed to enter. Additionally, crews were required to wear, or at least have with them, respirators in the event of a ventilation failure as it usually took a train a full hour to scale the tunnel.

Today, owner BNSF Railway has installed a ventilation system capable of removing exhaust within 20 minutes although crews are still required to have respirators with them at all times. For an idea of just how bad it could be for crewmen operating through Cascade Tunnel please read this account by John Crosby who worked this segment of the line during the Burlington Northern era. Train speeds today for BNSF freights and Amtrak passenger trains are held to 25 mph. One still has to wonder, however, why Burlington Northern did not exercise its ownership of nearby Snoqualmie Tunnel after the Milwaukee Road abandoned its main line in 1980. Using that bore, which was the best engineered tunnel across the Cascade range, would have saved BN and BNSF millions in maintenance costs and liability. For more reading about Snoqualmie Tunnel please click here.

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Also, for more reading about the Wellington train disaster I would highly recommend the book Vis Major by author Martin Burwash. Mr. Burwash describes in great detail the work done by the GN train crewmen and workforce in trying to get the line open during all of the days stuck on the mountainside. Essentially, the novel tells the story of the railroaders and their experience of the disaster. If you're interested in perhaps purchasing either (or both) of these books please visit the links below which will take you to ordering information through Amazon.com, the trusted online shopping network.

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