Cascade Tunnel
Encyclopedia
The Cascade Tunnel refers to two tunnels at Stevens Pass
through the Cascade Mountains
, approximately 65 miles (104.6 km) to the east of Everett, Washington
. The first Cascade Tunnel was a 2.63-mile (4.2 km) long single track railroad
, built by the Great Northern Railway in 1900 to avoid problems caused by heavy winter snowfalls on the original line that had eight Zig Zags
(switchback
s). The second tunnel, a 7.79-mile (12.5 km) single-track replacement of the earlier tunnel, was put in service on January 12, 1929 and is still in operation, connecting Chelan County on its east (Berne, WA) with King County
on its west (Scenic, WA). It is the longest railroad tunnel in the United States
.
was the principal engineer on the interim switchback route (opened in 1893, with grades up to 4.0 percent) and the first Cascade Tunnel. Stevens Pass
, located above the tunnels, was named after him.
The tunnel had a smoke (fume) problem, as it was built with a 1.7% (1:58.8) gradient eastbound, which was too close to the ruling gradient
of 2.2%. The tunnel was electrified
, with the project completed on July 10, 1909, eliminating the problem. The (unusual) system used was three-phase AC, of 6600 volts at 25 Hz from a 5 MW hydroelectric plant on the Wenatchee River just west of Leavenworth. The tunnel section only was electrified; 4.0 route-miles or 6.0 track-miles and 1.7 percent grade through the tunnel. Four 1500 hp locomotives of 115 tons each were supplied by the American Locomotive Co.
However, the tunnel was still plagued by snow slides in the area. On March 1, 1910, an avalanche at Wellington (renamed "Tye" after the disaster), the West portal of the original 2.6 miles (4 km)-long Cascade Tunnel, killed 96 people (or 101 people according to Middleton), 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 tunnel for a distance of one-half mile for the indeterminate future.
and Wenatchee
. The ruling grade was still 2.2 percent, although 21 miles of 2 percent or worse grade was eliminated. The line length was reduced by 8.7 miles, and maximum elevation was lowered by 502 feet (153 m) from 3382 feet (1,030.8 m) to 2881 feet (878.1 m). The new electric locomotives had a motor-generator
supplying DC traction motors, and the single-phase AC supply (11 kV, 25 Hz) required only one instead of two overhead conductors. Each Baldwin-Westinghouse Z-1 locomotive consisted of a pair of semi-permanently coupled 1-D-1 box-cab units. The pair weighed over 371 tons, and had an hourly rating of 4330 hp.
The new tunnel was started in December 1925, and was built in just over 3 years by A Guthrie of St Paul, Minnesota; the aim was to finish by the winter of 1928/29 so that further maintenance on deteriorating snow sheds could be avoided. While the new tunnel was being constructed, 21 miles between the original tunnel and Skykomish were electrified, even though 8 miles were abandoned when the new tunnel was opened. The three-phase electrification was abandoned from 5 March 1927 when the new locomotives were placed in service between Skykomish and the east portal of the old tunnel; the time was reduced from 4 hours for a 2500 ton eastbound train to 1 hour 45 minutes for a 3500 ton train, and for the first time regenerated power could be used by another train or fed back to the utility company (power from regenerative braking was previously dissipated in a water rheostat at the power station).
Electrification was removed in 1956, after a ventilation system was installed to eliminate diesel fumes.
On April 4, 1996 an eastbound freight train broke through the doors at the east portal after they did not open properly. There were no injuries, but the broken doors slowed operations for a couple of days while replacement doors were brought up from the Seattle area.
In Fall 2001 a single car derailed in the tunnel and was dragged the rest of the way out. It ripped out wiring that was attached to the sides of the tunnel.
The current Cascade Tunnel is in full operation and receives regular maintenance from BNSF Railway. The new alignment is a straight-line tunnel running between Berne and Scenic. It is currently part of the BNSF Railway
's Scenic Subdivision
between Seattle and Wenatchee
, and Amtrak
's Empire Builder
runs through it. Because of safety and ventilation issues, this tunnel is a limiting factor on how many trains the railroad can operate over this route from Seattle to Spokane. The current limit is 28 trains per day. Speed through the tunnel is 25 miles per hour (40 km/h).
The gradient in this tunnel is 1.565% (1:64), with the rise from west to east. The gradient is 2.2% on the west side from the town of Skykomish. Most recently, telecommunications assets and track sections inside the tunnel were improved.
A ventilation system is used to reduce problems with fumes. As a train enters the west portal of the tunnel, doors close on the east portal and huge fans blow in cool air through a second portal to help the diesel engines. As long as the train is within the tunnel, the fans work with reduced power to avoid pressure problems. After the train has left the tunnel, the colored door immediately closes and the fans operate for 20–30 minutes with maximum power to clear the tunnel of exhaust before the next train passes through. In the opposite direction, the door opens when the train is about 1 km (0.621372736649807 mi) away from it. The fans are powered by 800 horsepower motors. There are two fans. Over 7 miles of air is moved by a combined 1600 HP fan array. Both fans running can 'clean' the tunnel air within 20 minutes.
Present-day train crews carry portable respirators for use in the event of a fan failure or a train stalling inside the tunnel. In addition, there are emergency/safety stations spaced every 1500 and 2500 feet (460 and 760 m) apart, depending on the location within the tunnel, that provide additional air tanks and equipment to be used in the event of a ventilation/other failure.
Stevens Pass
Stevens Pass is a mountain pass through the Cascade Mountains located at the border of King County and Chelan County in Washington, United States....
through the Cascade Mountains
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...
, approximately 65 miles (104.6 km) to the east of Everett, Washington
Everett, Washington
Everett is the county seat of and the largest city in Snohomish County, Washington, United States. Named for Everett Colby, son of founder Charles L. Colby, it lies north of Seattle. The city had a total population of 103,019 at the 2010 census, making it the 6th largest in the state and...
. The first Cascade Tunnel was a 2.63-mile (4.2 km) long single track railroad
Rail transport
Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail tracks. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks they run on...
, built by the Great Northern Railway in 1900 to avoid problems caused by heavy winter snowfalls on the original line that had eight Zig Zags
Zig Zag (railway)
A railway zig zag, also called a switchback, is a way of climbing hills in difficult country with a minimal need for tunnels and heavy earthworks. For a short distance , the direction of travel is reversed, before the original direction is resumed.A location on railways constructed e.g...
(switchback
Hairpin turn
A hairpin turn , named for its resemblance to a hairpin/bobby pin, is a bend in a road with a very acute inner angle, making it necessary for an oncoming vehicle to turn almost 180° to continue on the road. Such turns in ramps and trails may be called switchbacks in American English, by analogy...
s). The second tunnel, a 7.79-mile (12.5 km) single-track replacement of the earlier tunnel, was put in service on January 12, 1929 and is still in operation, connecting Chelan County on its east (Berne, WA) with King County
King County, Washington
King County is a county located in the U.S. state of Washington. The population in the 2010 census was 1,931,249. King is the most populous county in Washington, and the 14th most populous in the United States....
on its west (Scenic, WA). It is the longest railroad tunnel in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
Original Tunnel
The first tunnel began construction on August 20, 1897 and was completed on December 20, 1900. John Frank StevensJohn Frank Stevens
John Frank Stevens was an American engineer who built the Great Northern Railway in the United States and was chief engineer on the Panama Canal between 1905 and 1907.- Biography :...
was the principal engineer on the interim switchback route (opened in 1893, with grades up to 4.0 percent) and the first Cascade Tunnel. Stevens Pass
Stevens Pass
Stevens Pass is a mountain pass through the Cascade Mountains located at the border of King County and Chelan County in Washington, United States....
, located above the tunnels, was named after him.
The tunnel had a smoke (fume) problem, as it was built with a 1.7% (1:58.8) gradient eastbound, which was too close to the ruling gradient
Ruling gradient
The term "ruling grade" is usually used as a synonym for "steepest climb" between two points on a railroad. But if the steepest climb is, say, a quarter-mile of 2% upgrade preceded and followed by 1.5% grade the "ruling grade" can only be defined arbitrarily....
of 2.2%. The tunnel was electrified
Railway electrification system
A railway electrification system supplies electrical energy to railway locomotives and multiple units as well as trams so that they can operate without having an on-board prime mover. There are several different electrification systems in use throughout the world...
, with the project completed on July 10, 1909, eliminating the problem. The (unusual) system used was three-phase AC, of 6600 volts at 25 Hz from a 5 MW hydroelectric plant on the Wenatchee River just west of Leavenworth. The tunnel section only was electrified; 4.0 route-miles or 6.0 track-miles and 1.7 percent grade through the tunnel. Four 1500 hp locomotives of 115 tons each were supplied by the American Locomotive Co.
However, the tunnel was still plagued by snow slides in the area. On March 1, 1910, an avalanche at Wellington (renamed "Tye" after the disaster), the West portal of the original 2.6 miles (4 km)-long Cascade Tunnel, killed 96 people (or 101 people according to Middleton), 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 tunnel for a distance of one-half mile for the indeterminate future.
Current Tunnel
The new Cascade Tunnel was opened on 12 January 1929. The new line had 72.9 route-miles or 93.2 track miles electrified, between SkykomishSkykomish, Washington
As of the census of 2000, there were 214 people, 104 households, and 58 families residing in the town. The population density was 623.2 people per square mile . There were 162 housing units at an average density of 471.8 per square mile...
and Wenatchee
Wenatchee, Washington
Wenatchee is located in North Central Washington and is the largest city and county seat of Chelan County, Washington, United States. The population within the city limits in 2010 was 31,925...
. The ruling grade was still 2.2 percent, although 21 miles of 2 percent or worse grade was eliminated. The line length was reduced by 8.7 miles, and maximum elevation was lowered by 502 feet (153 m) from 3382 feet (1,030.8 m) to 2881 feet (878.1 m). The new electric locomotives had a motor-generator
Motor-generator
A motor-generator is a device for converting electrical power to another form. Motor-generator sets are used to convert frequency, voltage, or phase of power. They may also be used to isolate electrical loads from the electrical power supply line...
supplying DC traction motors, and the single-phase AC supply (11 kV, 25 Hz) required only one instead of two overhead conductors. Each Baldwin-Westinghouse Z-1 locomotive consisted of a pair of semi-permanently coupled 1-D-1 box-cab units. The pair weighed over 371 tons, and had an hourly rating of 4330 hp.
The new tunnel was started in December 1925, and was built in just over 3 years by A Guthrie of St Paul, Minnesota; the aim was to finish by the winter of 1928/29 so that further maintenance on deteriorating snow sheds could be avoided. While the new tunnel was being constructed, 21 miles between the original tunnel and Skykomish were electrified, even though 8 miles were abandoned when the new tunnel was opened. The three-phase electrification was abandoned from 5 March 1927 when the new locomotives were placed in service between Skykomish and the east portal of the old tunnel; the time was reduced from 4 hours for a 2500 ton eastbound train to 1 hour 45 minutes for a 3500 ton train, and for the first time regenerated power could be used by another train or fed back to the utility company (power from regenerative braking was previously dissipated in a water rheostat at the power station).
Electrification was removed in 1956, after a ventilation system was installed to eliminate diesel fumes.
On April 4, 1996 an eastbound freight train broke through the doors at the east portal after they did not open properly. There were no injuries, but the broken doors slowed operations for a couple of days while replacement doors were brought up from the Seattle area.
In Fall 2001 a single car derailed in the tunnel and was dragged the rest of the way out. It ripped out wiring that was attached to the sides of the tunnel.
Operations
BNSF Railway
The BNSF Railway is a wholly owned subsidiary of Berkshire Hathaway Inc., and is headquartered in Fort Worth, Texas. It is one of seven North American Class I railroads and the second largest freight railroad network in North America, second only to the Union Pacific Railroad, its primary...
's Scenic Subdivision
Scenic Subdivision
The Scenic Subdivision or Scenic Sub is a railway line running about from Seattle, WA to Wenatchee, WA. It is operated by BNSF Railway as part of their Northern Transcon and contains the record setting Cascade Tunnel as well as the final spike completion site, in 1893, at Scenic, WA, for the whole...
between Seattle and Wenatchee
Wenatchee, Washington
Wenatchee is located in North Central Washington and is the largest city and county seat of Chelan County, Washington, United States. The population within the city limits in 2010 was 31,925...
, and Amtrak
Amtrak
The National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...
's Empire Builder
Empire Builder
The Empire Builder is a passenger train route operated by Amtrak in the Midwestern and Northwestern United States. It is Amtrak's busiest long-distance route and busiest daily train, carrying more than 500,000 travelers annually since 2007. Overall, it is the railroad's 10th-busiest line. Before...
runs through it. Because of safety and ventilation issues, this tunnel is a limiting factor on how many trains the railroad can operate over this route from Seattle to Spokane. The current limit is 28 trains per day. Speed through the tunnel is 25 miles per hour (40 km/h).
The gradient in this tunnel is 1.565% (1:64), with the rise from west to east. The gradient is 2.2% on the west side from the town of Skykomish. Most recently, telecommunications assets and track sections inside the tunnel were improved.
A ventilation system is used to reduce problems with fumes. As a train enters the west portal of the tunnel, doors close on the east portal and huge fans blow in cool air through a second portal to help the diesel engines. As long as the train is within the tunnel, the fans work with reduced power to avoid pressure problems. After the train has left the tunnel, the colored door immediately closes and the fans operate for 20–30 minutes with maximum power to clear the tunnel of exhaust before the next train passes through. In the opposite direction, the door opens when the train is about 1 km (0.621372736649807 mi) away from it. The fans are powered by 800 horsepower motors. There are two fans. Over 7 miles of air is moved by a combined 1600 HP fan array. Both fans running can 'clean' the tunnel air within 20 minutes.
Present-day train crews carry portable respirators for use in the event of a fan failure or a train stalling inside the tunnel. In addition, there are emergency/safety stations spaced every 1500 and 2500 feet (460 and 760 m) apart, depending on the location within the tunnel, that provide additional air tanks and equipment to be used in the event of a ventilation/other failure.
See also
- GN W-1GN W-1The Great Northern Railway's class W-1 comprised two electric locomotives with AAR B-D+D-B wheel arrangements. The locomotives were used on the electrified portion of the railroad, from Wenatchee, Washington to Skykomish, Washington, including the Cascade Tunnel.The W-1 motor-generator...
, large electric locomotives used on the Cascade Tunnel route. - Otira TunnelOtira TunnelThe Otira Tunnel is a railway tunnel on the Midland Line in the South Island of New Zealand between Otira and Arthur's Pass. It runs under the Southern Alps from Arthur's Pass to Otira - a length of over . The gradient is mainly 1 in 33, and the Otira end of the tunnel is over lower than the...
, a tunnel in New ZealandNew ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
with similar characteristics.
External links
- University of Washington Libraries Digital Collections – Lee Pickett Photographs Over 1400 photographs documenting scenes from Snohomish, King and Chelan Counties in Washington State from the early 1900s to the 1940s. Includes images of the Cascade Tunnel construction.
- Cascade Tunnel # 15 - Pictures and details of the Fanhouse at the east portal of the tunnel
- Radio Broadcast of the 1929 Cascade Tunnel Dedication