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Cascade Tunnel
The Cascade Tunnel refers to two railroad tunnels, its original tunnel and its replacement, in the northwest United States, east of the Seattle metropolitan area in the Cascade Range of Washington, at Stevens Pass. It is approximately 65 miles (105 km) east of Everett, with both portals adjacent to U.S. Route 2. Both single-track tunnels were constructed by the Great Northern Railway.
The first was 2.63 miles (4.23 km) in length and opened in 1900 to avoid problems caused by heavy winter snowfalls on the original line that had eight zig zags (switchbacks). The current tunnel is 7.8 miles (12.6 km) in length and entered service in early 1929, approximately 1.5 miles (2.4 km) south of and 500 feet (150 m) lower in elevation than the original. The present east portal is nearly four miles (6.5 km) east of the original and is at 2,881 feet (878 m) above sea level, 1,180 feet (360 m) below the pass. The tunnel connects Berne in Chelan County on its east with Scenic Hot Springs in King County on its west and is the longest railroad tunnel in the United States.
Construction began on the first tunnel on August 20, 1897, and was completed on December 20, 1900. The tunnel was 2.6 miles (4.2 km) long. John Frank Stevens was the principal engineer on the interim switchback route (opened in 1893, with grades up to 4 percent) and the first Cascade Tunnel. Stevens Pass, located above the tunnels, was named after him.
The tunnel had a fume problem from the coal-burning steam locomotives. It was built with a 1.7% (1:58.8) gradient eastbound, which was too close to the ruling gradient of 2.2%. Because of the steepness of the line, the locomotives had to pull hard to make the grade and thus burn more coal, which would lead to immense smoke in the bore. The tunnel was electrified, with the project completed on July 10, 1909, eliminating the problem. The unusual system used was three-phase AC, 6.6 kilovolts at 25 Hz, from a 5 MW (6,700 hp) hydroelectric plant on the Wenatchee River just west of Leavenworth. The tunnel section only was electrified; 4.0 route miles (6.4 km) or 6.0 track miles (9.7 km) and 1.7 percent grade through the tunnel chamber.
The motive power for the section consisted of four GN boxcab locomotives supplied by the American Locomotive Company; they used electrical equipment from General Electric and were of 1,500 horsepower (1,100 kW) and weighed 115 short tons (104 t) each. Initially three locomotives were coupled together and hauled trains at a constant speed of 15.7 mph (25.3 km/h), but when larger trains required four locomotives the motors were concatenated (cascade control), so that the speed was halved to 7.8 mph (12.6 km/h) to avoid overloading the power supply. The consulting engineer, Cary T. Hutchinson, published a detailed description of the system in 1909.
The tunnel was still plagued by snow slides in the area. On March 1, 1910, an avalanche at Wellington (renamed Tye after the disaster) near the west portal of the original 2.6 miles (4.2 km) Cascade Tunnel, killed 96–101 people, the deadliest avalanche disaster in U.S. history. This disaster prompted the construction of the current tunnel.
The old tunnel was abandoned in 1929, after the new longer and lower tunnel was opened. During the winter of 2007–2008, a section of the roof caved in and created a debris dam inside the tunnel, making it impassable to pedestrians due to standing water and ceiling debris. A warning was issued to stay clear of the western side of the old tunnel for a distance of 0.5 mi (0.80 km) for the indeterminate future.
The new Cascade Tunnel was opened on January 12, 1929. The new line had 72.9 route mi (117.3 km) or 93.2 route miles (150.0 km) electrified, between Skykomish and Wenatchee. The ruling grade was still 2.2 percent, although 21 miles (34 km) of 2 percent or worse grade was eliminated. The line length was reduced by 8.7 miles (14 km), and maximum elevation was lowered by 502 feet (153 m) from 3,382 feet (1,031 m) to 2,881 feet (878 m).
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Cascade Tunnel
The Cascade Tunnel refers to two railroad tunnels, its original tunnel and its replacement, in the northwest United States, east of the Seattle metropolitan area in the Cascade Range of Washington, at Stevens Pass. It is approximately 65 miles (105 km) east of Everett, with both portals adjacent to U.S. Route 2. Both single-track tunnels were constructed by the Great Northern Railway.
The first was 2.63 miles (4.23 km) in length and opened in 1900 to avoid problems caused by heavy winter snowfalls on the original line that had eight zig zags (switchbacks). The current tunnel is 7.8 miles (12.6 km) in length and entered service in early 1929, approximately 1.5 miles (2.4 km) south of and 500 feet (150 m) lower in elevation than the original. The present east portal is nearly four miles (6.5 km) east of the original and is at 2,881 feet (878 m) above sea level, 1,180 feet (360 m) below the pass. The tunnel connects Berne in Chelan County on its east with Scenic Hot Springs in King County on its west and is the longest railroad tunnel in the United States.
Construction began on the first tunnel on August 20, 1897, and was completed on December 20, 1900. The tunnel was 2.6 miles (4.2 km) long. John Frank Stevens was the principal engineer on the interim switchback route (opened in 1893, with grades up to 4 percent) and the first Cascade Tunnel. Stevens Pass, located above the tunnels, was named after him.
The tunnel had a fume problem from the coal-burning steam locomotives. It was built with a 1.7% (1:58.8) gradient eastbound, which was too close to the ruling gradient of 2.2%. Because of the steepness of the line, the locomotives had to pull hard to make the grade and thus burn more coal, which would lead to immense smoke in the bore. The tunnel was electrified, with the project completed on July 10, 1909, eliminating the problem. The unusual system used was three-phase AC, 6.6 kilovolts at 25 Hz, from a 5 MW (6,700 hp) hydroelectric plant on the Wenatchee River just west of Leavenworth. The tunnel section only was electrified; 4.0 route miles (6.4 km) or 6.0 track miles (9.7 km) and 1.7 percent grade through the tunnel chamber.
The motive power for the section consisted of four GN boxcab locomotives supplied by the American Locomotive Company; they used electrical equipment from General Electric and were of 1,500 horsepower (1,100 kW) and weighed 115 short tons (104 t) each. Initially three locomotives were coupled together and hauled trains at a constant speed of 15.7 mph (25.3 km/h), but when larger trains required four locomotives the motors were concatenated (cascade control), so that the speed was halved to 7.8 mph (12.6 km/h) to avoid overloading the power supply. The consulting engineer, Cary T. Hutchinson, published a detailed description of the system in 1909.
The tunnel was still plagued by snow slides in the area. On March 1, 1910, an avalanche at Wellington (renamed Tye after the disaster) near the west portal of the original 2.6 miles (4.2 km) Cascade Tunnel, killed 96–101 people, the deadliest avalanche disaster in U.S. history. This disaster prompted the construction of the current tunnel.
The old tunnel was abandoned in 1929, after the new longer and lower tunnel was opened. During the winter of 2007–2008, a section of the roof caved in and created a debris dam inside the tunnel, making it impassable to pedestrians due to standing water and ceiling debris. A warning was issued to stay clear of the western side of the old tunnel for a distance of 0.5 mi (0.80 km) for the indeterminate future.
The new Cascade Tunnel was opened on January 12, 1929. The new line had 72.9 route mi (117.3 km) or 93.2 route miles (150.0 km) electrified, between Skykomish and Wenatchee. The ruling grade was still 2.2 percent, although 21 miles (34 km) of 2 percent or worse grade was eliminated. The line length was reduced by 8.7 miles (14 km), and maximum elevation was lowered by 502 feet (153 m) from 3,382 feet (1,031 m) to 2,881 feet (878 m).
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