Cascade tunnel
The Cascade Tunnel is a single-track railway tunnel and runs under Stevens Pass through the North American Cascade Range . The name Cascade Tunnel refers to both the current tunnel between Scenic and Berne in the US state of Washington with a length of 12.5 km and an older vertex tunnel , which was closed in 1929, between Tye (formerly Wellington) and the Cascade Station depot with a length of 4 , 2 km.
The old tunnel
| (Old) Cascade Tunnel | ||||
|---|---|---|---|---|
| use | Railway tunnel | |||
| traffic connection | Scenic subdivision | |||
| place | Cascade chain | |||
| length | 4210 m | |||
| Number of tubes | 1 | |||
| construction | ||||
| Client | Great Northern Railway | |||
| start of building | August 20, 1897 | |||
| completion | 20th December 1900 | |||
| business | ||||
| operator | Great Northern Railway | |||
| Cascade tunnel | ||||
 Course of the old and new Cascade Tunnels, the old route over Stevens Pass and the US Highway 2
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| location | ||||
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| Coordinates | ||||
| 47 ° 46 ′ 22 " N , 121 ° 4 ′ 43" W. | ||||
| 47 ° 44 ′ 58 " N , 121 ° 7 ′ 10" W. | ||||
Map with all coordinates: The first tunnel replaced the old railway line on the Stevens Pass which eight switchbacks had and difficult to operate in winter on the heavy snowfalls.
construction
Construction began on August 20, 1897 under the direction of John Frank Stevens , after whom the Stevens Pass is named. The tunnel was put into operation on December 20, 1900.
business
Steam operation
After the opening, the tunnel was used by steam locomotives . The 17 ‰ gradient inside the tunnel was a challenge for the eastbound trains. The trains weighing between 1,300 and 1,400 tons were each hauled by two mallet locomotives . All trains stopped in the station in front of the western tunnel portal so that the locomotive fires could be charged with high-quality coal and the fire could be coked so that as much excess gas as possible could escape from the coal and as little smoke as possible should arise in the tunnel. This process took an hour or more until the locomotives were ready to travel through the tunnel.
For the journey through the tunnel, the trains had to be divided so that two locomotives with no more than 1000 t had to drive up the incline. Although the tunnel was laid out in an east-west direction and the prevailing westerly wind was supposed to help ventilate the tunnel, it was almost impossible to drive through the tunnel in unfavorable weather conditions because the smoke from the steam locomotives did not escape. After a train ride, you had to wait two to three hours before the next train could safely drive through the tunnel. The boiler pressure of the second locomotive often fell from 14 bar to 5 bar or less because it was impossible to keep the fire properly running in the low-oxygen air.
electrification
To solve this problem, the 6.4 km long section between was Wellington and the depot Cascade Station electrified . The electrical operation began on July 10, 1909. The Great Northern Railway procured four three-phase current locomotives of the class 5000 , which were supplied with energy via a two-pole overhead contact line and the running rails as the third phase conductor . As current system has three-phase alternating current with a voltage of 6,600 volts and a power frequency of 25 Hertz selected.
Power plant and transmission line
The electrical energy required was supplied by the specially built power plant in Tumwater Canyon about 40 km west of the tunnel. The water from the Tumwater Dam on the Wenatchee River was used to drive the three Francis turbines . A 3,4 km long from the dam resulted from wooden staves manufactured pressure pipe to the turbine building. Next to the machine house was a 64 m high 3800 m³ steel tank that served as a water lock. Each of the three generators had an output of 2 MW. The voltage in the power plant was increased to 33 kV and brought to the tunnel via a 48 km long high-voltage line.
attitude
In 1927, in anticipation of the new tunnel under construction, electrical operation was extended westwards to Skykomish . On this occasion, the three-phase alternating current system was abandoned, the two-pole overhead line dismantled and the line re-electrified with 11 kV, 25 Hz alternating voltage . The 4 -phase current locomotives are of the electric locomotives of class Z-1 peeled off.
Misfortunes and incidents
The operation of the tunnel was also made difficult in winter by extreme snowfalls and endangered by avalanches . On March 1, 1910 , 96 people were killed in an avalanche disaster, the Wellington railway accident. Two trains were torn into the valley. Wellington was then renamed Tye .
Shutdown
In 1929 the old tunnel was shut down after the new tunnel went into operation. The tunnel still exists today, but is in danger of collapsing and therefore must not be entered.
The tunnel and system of switchbacks were added to the List of Historic Civil Engineering Landmarks by the American Society of Civil Engineers in 1993.
The new tunnel
| (New) Cascade Tunnel | ||||
|---|---|---|---|---|
| use | Railway tunnel | |||
| traffic connection | Scenic subdivision | |||
| place | Cascade chain | |||
| length | 12,537 m (from 1956 12,547 m) | |||
| Number of tubes | 1 | |||
| construction | ||||
| Client | Great Northern Railway | |||
| start of building | December 28, 1925 | |||
| completion | January 12, 1929 | |||
| business | ||||
| operator |
Great Northern Railway (until 1970), Burlington Northern (1970-2005), BNSF (since 2005) |
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| Cascade tunnel | ||||
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Course of the old and new Cascade Tunnels, the old route over Stevens Pass and the US Highway 2
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| location | ||||
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| Coordinates | ||||
| 47 ° 46 ′ 12 ″ N , 120 ° 59 ′ 56 ″ W. | ||||
| 47 ° 42 ′ 55 " N , 121 ° 8 ′ 43" W. | ||||
The Wellington avalanche disaster prompted the planning of the new tunnel. This is 153 m (502 ft ) lower than the old one and shortens the railway line by 14 km (8.7 miles ).
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construction
Construction began on December 28, 1925 and was carried out by A. Guthrie and Company . The aim was to complete the tunnel before the winter of 1928/1929 in order to save the effort required to maintain the avalanche galleries . On January 12, 1929, the 25 million US dollar tunnel was opened. With a length of 12.5 km (7.77 miles), the Cascade Tunnel was the longest railway tunnel in the Western Hemisphere and the third longest in the world.
business
The gradient of the route is 16 ‰ inside the tunnel and up to 22 ‰ on the rest of the route. The same operational problems arose as with the old tunnel.
Electrical operation 1929–1956
With the commissioning of the tunnel in 1929, electrical operation was extended to the 117 km (73.9 miles) stretch between Wenatchee in the east and Skykomish in the west. By using Umformerlokomotiven the classes Z-1 and Y-1 , it became possible when braking energy into the catenary feed back . With the class W-1 , the largest electric locomotives ever used in North America were used on this route from 1946.
In operation since 1956
The electrical equipment should have been renewed in 1956. The Great Northern Railway decided to give up electrical operations and instead invest in mechanical ventilation to make the tunnel passable for diesel locomotives . As a result, the re-clamping that was required up until then was no longer necessary.
A gate and a machine room for the tunnel ventilation system were built at the eastern tunnel portal . This lengthened the tunnel by 10 m. Two blowers with an output of 597 kW (800 hp ) each are installed.
As soon as a train enters the tunnel from the west, the gate closes and fresh air is blown into the tunnel. In this way, cool, oxygen-rich air is supplied to the diesel engines of the locomotives. As long as the train is in the tunnel, the fans work with reduced power , otherwise the pressure difference between the tunnel and the outside air would be too great . The gate is opened in front of the train and closed again immediately after it has passed through. The fans then run at full power for 20 minutes to remove exhaust gases from the tunnel. For trains in the opposite direction, the gate opens when they are about 1 km away.
The train crew has breathing apparatus with them in the event that the ventilation system fails or the train comes to a standstill in the tunnel. In the event of an emergency, oxygen bottles and other equipment are available in the tunnel at a distance of 460–760 m (1,500–2,500 ft) .
The speed limit in the tunnel is 40 km / h (25 mph). Due to the ventilation method described, the number of trains passing through the tunnel is limited to 28 per day.
The Great Northern Railway went on in 1970 in the Burlington Northern Railroad . This in turn merged in 2005 with the Atchison, Topeka and Santa Fe Railway to form the BNSF Railway , from which the tunnel is operated today.
The Amtrak- operated Empire Builder also runs through the tunnel .
Misfortunes and incidents
On April 4, 1996, an eastbound train broke through the gate after it did not open in time. There were no injuries or deaths to complain about. In autumn 2001 a car derailed in the tunnel damaged various technical equipment.
literature
- William D. Middleton: When the Steam Railways Electrified . Kalmbach Books, Milwaukee 1974, ISBN 0-89024-028-0 .
- Charles & Dorothy Wood: The Great Northern Railway . Pacific Fast Mail, Edmonds, WA 1979, ISBN 0-915713-19-5 .
Web links
- Stevens Pass, Washington - Places by Robert D. West ( June 8, 2012 memento in the Internet Archive )
- University of Washington Libraries Digital Collections - Lee Pickett Photographs (Engl.)
- Cascade tunnel (Engl.)
Individual evidence
- ^ A b Edward P. Burch: Electric traction for railway trains . McGraw-Hill Book Company, New York 1911, Service with steam locomotives, p. 352-353 ( archive.org ).
- ↑ a b Tumwater Dam. In: gngoat.org. Retrieved November 29, 2019 .
- ^ A b Edward P. Burch: Electric traction for railway trains . McGraw-Hill Book Company, New York 1911, Power & Transmission Line, pp. 350 ( archive.org ).
- ↑ McCoild, Pat: Book review 'White Cascade' details drama of deadly 1910 railroad disaster . In: The News Tribune (Tacoma, Washington), February 25, 2007, p. E08.
- ↑ 125 Years of Top Projects . In: Engineering News-Record 243 (1999), No. 4, p. 41.
- ^ Washington State 2010–2030 Freight Rail Plan. Retrieved June 28, 2020 (English). (PDF; 2.9 MB).
Existing routes: Jungfrau Railway 1898 | Gornergratbahn 1898 | Chemin de Fer de la Rhune 1914/24 | Corcovado mountain railway 1910
Lines that were later re-electrified: Veltlinbahn | Ferrovia Alta Valtellina | Mont Cenis Railway | Trento burner | Bolzano – Merano | Firenze-Bologna | TEL Tram Lugano 1896–1910 | StEB Stansstad – Engelberg 1898–1964 | BTB Burgdorf – Thun Railway 1899–1933 | SSS / SStB Schwyzer trams 1900–1914 | SBB / BBC three-phase operation Brig – Iselle 1906–1930 | Great Northern Old Cascade Tunnel 1909–1927 | RhW Tram Rheineck 1909–1958 | RENFE Gérgal – Santa Fe-Alhama 1911–1966 | SBB Sion – Brig 1919–1927 | EB Hasle-Rüegsau – Langnau 1919–1932
Earlier three-phase electrifications : Riffelalptram 1898–1960 | Hotel tram Évian-les-Bains 1898–1908 | Wöllersdorf military track 1902–1911 | BrMB Brunnen-Morschach Railway 1905–1969 | CFHMP Luchon – Superbagnières de Luchon 1912–1966 | Mühleggbahn 1950–1975 | RAG cog railway opencast mine Gruhlwerk 1927–1949
Test operations: Three-phase test operation from Siemens & Halske | Ganz test track on Óbuda Island | Three-phase test operation Brig – Iselle