Editing Cascade Tunnel

{{Short description|Rail tunnels in Washington state, US}}
{{use mdy dates|date=May 2024}}
<!--[[File:BNSF Scenic-Sub-1700-Cascade-Tunnel.jpg|thumb|250px|Cascade Tunnel eastern portal]]-->
{{Infobox tunnel
| name          = Cascade Tunnel
| image         = BNSF Scenic-Sub-1700-Cascade-Tunnel.jpg
| image_size    = 230
| alt           = 
| caption       = The eastern portal of Cascade Tunnel in 2012
| official_name = 
| other_name    = 
| line          = [[BNSF Railway|BNSF]] [[Scenic Subdivision]] (formerly [[Burlington Northern Railway|Burlington Northern]] and [[Great Northern Railway (U.S.)|Great Northern]]) 
| location      = {{nowrap|[[Stevens Pass]], [[Washington (state)|Washington]], U.S.}}
| coordinates   = {{nowrap|{{coord|47|44|33|N|121|04|10|W|type:railwaystation|display=it}}}}
| os_grid_ref   = 
| status        = Active
| system        = 
| crosses       = [[Cascade Range]],<br /> near [[Stevens Pass]]
| start         = 
| end           = 
| stations      = 
| startwork     = 
| opened        = 1929, {{Time ago|1929}}<ref name=gtoprdy>{{cite news |url=https://news.google.com/newspapers?id=3s1XAAAAIBAJ&sjid=s_QDAAAAIBAJ&pg=5471%2C2572272 |work=Spokane Daily Chronicle |location=(Washington) |agency=Associated Press |title=Great tunnel opening ready |date=January 12, 1929 |page=1}}</ref><ref name=wonbore>{{cite news |url=https://news.google.com/newspapers?id=2gxWAAAAIBAJ&sjid=H-IDAAAAIBAJ&pg=6317%2C1944401|work=Spokesman-Review|location=(Spokane, Washington)|title=Wheels thunder in wonder bore |date=January 13, 1929 |page=1, part 1}}</ref> <!-- or |opens for future dates -->
| closed        = <!-- or |closes for future dates -->
| rebuilt       = 
| reopened      = <!-- or |reopens for future dates -->
| owner         = 
| operator      = 
| traffic       = [[Rail transport|Railroad]]
| character     = Primarily freight service<br />Some passenger service ([[Amtrak]])<!-- Empire Builder -->
| engineer      = 
| construction  = 
| length        = {{convert|7.80|mi|2}} <!-- 41,183 ft -->
| linelength    = 
| tracklength   = 
| notrack       = [[Single-track railway|Single]] 
| gauge         = {{Track gauge|ussg|allk=on}}
| el            = 
| speed         = 
| hielevation   = {{convert|2881|ft|-1}}
| lowelevation  = 
| height        = 
| width         =
| depth_below_water =
| shipping_clearance_above = 
| grade         = 
| map           = [[File:Cascade Tunnel Stevens Pass.jpg|250px]]
| extra         = {{Infobox mapframe}}
}}
The '''Cascade Tunnel''' refers to two [[Rail Transport|railroad]] [[tunnel]]s, its original tunnel and its replacement, in the [[Pacific Northwest|northwest]] [[United States]], east of the [[Seattle metropolitan area]] in the [[Cascade Range]] of [[Washington (state)|Washington]], at [[Stevens Pass]]. It is approximately {{convert|65|mi|round=5}} east of [[Everett, Washington|Everett]], with both portals adjacent to {{nowrap|[[U.S. Route 2 in Washington|U.S. Route 2]].}} Both single-track tunnels were constructed by the [[Great Northern Railway (U.S.)|Great Northern Railway]].

The first was {{convert|2.63|mi}} in length and opened in 1900 to avoid problems caused by heavy winter snowfalls on the original line that had eight [[Zig zag (railway)|zig zags]] ([[Hairpin turn|switchbacks]]). The current tunnel is {{convert|7.8|mi}}<!--41,183 feet--> in length and entered service in early {{nowrap|1929,<ref name=gtoprdy/><ref name=wonbore/>}} approximately {{convert|1.5|mi}} south of and {{convert|500|ft}} lower in [[elevation]] than the original. The present east portal is nearly {{convert|4|mi|round=0.5|spell=in}} east of the original and is at {{convert|2881|ft}} above [[sea level]], {{convert|1180|ft}} below the pass. The tunnel connects Berne in [[Chelan County, Washington|Chelan County]] on its east with [[Scenic Hot Springs]] in [[King County, Washington|King County]] on its west and is the longest railroad tunnel in the United States.

== History ==
===Original tunnel===
[[File:Great Northern Railway Oriental Limited Cascade Tunnel 1918.JPG|thumb|The [[Oriental Limited]] emerging from the old tunnel in 1918. The train was pulled by a [[Great Northern boxcab (3 phase)|Great Northern boxcab]] locomotive.]]

Construction began on the first tunnel on August 20, 1897, and was completed on December 20, 1900. The tunnel was {{convert|2.6|mi}} 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) [[Grade (slope)#Railways|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 [[railway electrification system|electrified]], with the project completed on July 10, 1909, eliminating the problem. The unusual system used was [[Three-phase AC railway electrification|three-phase AC]], 6.6 kilovolts at 25&nbsp;Hz, from a {{cvt|5|MW|hp}} hydroelectric plant on the Wenatchee River just west of Leavenworth. The tunnel section only was electrified; {{convert|4.0|mi||adj=pre|route}} or {{convert|6.0|mi||adj=pre|track}} and 1.7 percent grade through the tunnel chamber.

The motive power for the section consisted of four [[Great Northern boxcab (3 phase)|GN boxcab]] locomotives supplied by the [[American Locomotive Company]]; they used electrical equipment from [[General Electric]] and were of {{convert|1500|hp}} and weighed {{convert|115|ST|tonne}} each.<ref>{{cite journal | title = Electric Locomotives for the Great Northern | journal = The Railroad Gazette | date=1909 | volume = 46 | issue = 1 | pages = 120–122 | url = https://archive.org/details/RailwayAge1909GreatNorthernElectricLocomotivesRailwayage46newy }}</ref>{{sfnp|Haut|1969|p=27}} Initially three locomotives were coupled together and hauled trains at a constant speed of {{convert|15.7|mph|abbr=on}},{{sfnp|American Railway Association, (Division V - Mechanical)|1922|p=901}} but when larger trains required four locomotives the motors were concatenated (cascade control), so that the speed was halved to {{convert|7.8|mph|abbr=on}} to avoid overloading the power supply. The consulting engineer, Cary T. Hutchinson, published a detailed description of the system in 1909.{{sfnp|Hutchinson|1909}}

{{main|Wellington, Washington avalanche}}
The tunnel was still plagued by snow slides in the area. On March 1, 1910, an avalanche at [[Wellington, Washington|Wellington]] (renamed Tye after the disaster) near the west portal of the original {{convert|2.6|mi}} Cascade Tunnel, killed 96–101{{sfn|Roe|1995|pp=79–91}}<ref>{{harvnb|Middleton|1974}}{{Page needed|date=July 2017}}</ref> people, the deadliest avalanche disaster in U.S. history.<ref>{{cite news |url=https://www.king5.com/article/news/history/deadliest-avalanche-us-history-stevens-pass-washington |title=Deadliest US avalanche was 111 years ago near Stevens Pass |date=March 1, 2021 |publisher=KING5}}</ref> 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 {{cvt|0.5|mi}} for the indeterminate future.

===Current tunnel===
{{more citations needed section|date=July 2015}}
[[File:Cascade Tunnel Great Northern Railway illustration.JPG|thumb|left|Postcard illustration of the old and new tunnels from the Great Northern Railway]]
[[File:Great Northern officials at Cascade Tunnel 1926.jpg|thumb|Railroad officials at the Mill Creek shaft, allowing excavation to proceed outwards from within the mountains]] 
[[File:Great Northern Railway and A. Guthrie Co. officials at the entrance to the Cascade Tunnel, the longest tunnel in America (7.8 miles).jpg|thumb|Opening of the new tunnel, January 12, 1929]]

The new Cascade Tunnel was opened on January 12, 1929.<ref name=gtoprdy/><ref name=wonbore/> The new line had {{cvt|72.9|mi||adj=pre|route}} or {{convert|93.2|mi||adj=pre|route}} electrified, between [[Skykomish, Washington|Skykomish]] and [[Wenatchee, Washington|Wenatchee]]. The ruling grade was still 2.2 percent, although {{convert|21|mi}} of 2 percent or worse grade was eliminated. The line length was reduced by {{convert|8.7|mi|0}}, and maximum elevation was lowered by {{convert|502|ft}} from {{convert|3382|ft}} to {{convert|2881|ft}}.

The new tunnel was started in December 1925, and was built in just over three years by A. Guthrie of [[St. Paul, Minnesota]]; the aim was to finish by the winter of 1928–1929 so that further maintenance on deteriorating snow sheds could be avoided. Project manager and engineer [[Frederick Mears]] was assigned to make sure the project was completed.{{sfnp|Cascade Tunnel (Part 1)|1929}}<ref name="Echo">{{cite web|last1=Jordan|first1=Lee|title=Railroad Created Alaska's Largest City|url=https://www.echoak.com/2017/04/alaska-railroad/|website=Echo News|accessdate=3 July 2017}}</ref>

While the new tunnel was being constructed, the Great Northern received delivery of [[Great Northern Z-1|five new electric locomotives]]. The new locomotives had a [[motor-generator]] supplying DC traction motors, and the single-phase AC supply required only one instead of two overhead conductors. Hence, the Great Northern re-electrified {{convert|21|mi}} of the original route at single-phase (11 kV, 25&nbsp;Hz) AC, including {{convert|8|mi}} that were subsequently abandoned upon completion of the new tunnel, and used steam locomotives on the short remaining stretches of the old line.

On March 5, 1927, the three-phase electrification was abandoned, and 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 {{cvt|2500|ST|t}} eastbound train to 1 hour 45 minutes for a {{cvt|3500|ST|t}} train. Furthermore, 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 [[Liquid rheostat|water rheostat]] at the power station).<ref name=":0">{{harvnb|Middleton|1974|pp=163-169}}</ref>

Two years later, the new tunnel opened.<ref name=":0" /> It was the longest railroad tunnel in the Americas until 1989, when the [[Mount Macdonald Tunnel]] in [[British Columbia]] was completed, moving the Cascade into second place.

Electrification was removed in 1956, after a ventilation system was installed to eliminate diesel fumes.<ref>{{Harvnb|Hidy|Hidy|Scott|Hofsummer|2004|pp=267–268}}</ref>

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.{{citation needed|date=December 2016}}

[[File:Railway and locomotive engineering - a practical journal of railway motive power and rolling stock (1928) (14574492017).jpg|thumb|The [[Great Northern Z-1]], one of the locomotives used on the new Cascade Tunnel]]
[[File:Great Northern electric locomotive Y-1 1927.JPG|thumb|The [[Great Northern Y-1]], the other locomotive used on the current tunnel]]

== Operations ==
[[Image:Cascade Tunnel.jpg|thumb|<!--The-->East Portal doors<!-- of the Cascade Tunnel--> opening<!--so a train can pass through-->]]
[[File:CascadeTunnelWestPortal.jpg|thumb|West Portal<!--of the Cascade Tunnel--> in 2011]]

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 Hot Springs. It is currently part of the [[BNSF Scenic Subdivision]] between [[Seattle]] and [[Wenatchee, Washington|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.<ref>{{Cite web |url=http://www.wsdot.wa.gov/NR/rdonlyres/34925D95-4F59-44B6-90DD-6BE102B33C15/0/StateFreightRailPlan.pdf |title=Washington State, 2010–2030 Freight Rail Plan, pg 81 |access-date=2011-02-12 |archive-url=https://web.archive.org/web/20121224140702/http://www.wsdot.wa.gov/NR/rdonlyres/34925D95-4F59-44B6-90DD-6BE102B33C15/0/StateFreightRailPlan.pdf |archive-date=2012-12-24 |url-status=dead }}</ref> Speed through the tunnel is {{convert|30|mph}} for passenger trains, {{convert|25|mph}} for freight trains.

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.{{When|date=February 2011}}

===Ventilation operations===
Because of the length of the tunnel, an unusual system is used to ensure that the air inside remains breathable and reduce problems with excess [[Exhaust gas|fumes]]. As a train enters the west portal of the tunnel, a red-and-white-checkered door closes on the east portal and high-power 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. When the train is {{convert|0.5|mi|0}} to the tunnel exit, the door begins to open.{{citation needed|date=August 2020}}

Once the train has cleared the tunnel, the door closes again and the fans operate for 20 to 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 within {{convert|0.6|mi|0}}. The fans are powered by two {{convert|800|hp}} electric motors, clearing the air through the {{convert|7|mi|0|spell=in}} of tunnel 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 {{convert|1500|–|2500|ft|-1}} 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.

The tunnel door is protected by an [[railway signal|absolute signal]] near the east portal; on the west side, another signal with dual-flashing [[Glossary of rail transport terms#Lunar|lunar]] aspects indicates to eastbound trains that the tunnel fans are operating.

== See also ==
{{div col|colwidth=30em}}
* [[Flathead Tunnel]], an active tunnel in [[Montana]] also built by the Great Northern<!--and used by both the [[Burlington Northern Railway|Burlington Northern]] and [[BNSF]] Railways-->
* [[Great Northern W-1]], large electric locomotives used on the Cascade Tunnel route
* [[Lists of tunnels]]
* [[Moffat Tunnel]], a similar railroad tunnel in [[Colorado]]
* [[Mount Macdonald Tunnel]], a similar railroad tunnel in [[British Columbia]]
* [[Otira Tunnel]], a tunnel in [[New Zealand]] with similar characteristics
* [[Snoqualmie Tunnel]], Milwaukee Road near Snoqualmie Pass (inactive, now a [[rail trail]])
* [[Stampede Pass#Stampede Tunnel|Stampede Tunnel]], Northern Pacific at Stampede Pass
{{div col end}}

== Notes ==
{{Reflist|30em}}

== References ==
{{refbegin}}
* {{1922 Locomotive Cyclopedia}} {{sfn whitelist|CITEREFAmerican_Railway_Association,_(Division_V_-_Mechanical)1922}}
* {{citation |last=Cascade Tunnel (Part 1) | journal = The Engineer | date =14 June 1929 | title = The Cascade Tunnel : Great Northern Railway, U.S.A (No.I)| pages =644–646 | url =http://www.gracesguide.co.uk/images/3/36/Er19290614.pdf | volume =147}}
* {{citation |last=Cascade Tunnel (Part 2)| journal = The Engineer | date = 21 June 1929 | title = The Cascade Tunnel : Great Northern Railway, U.S.A (No.II) | pages =672–674 | url=http://www.gracesguide.co.uk/images/7/74/Er19290621a.pdf | volume =147}}
* {{citation |last=Cascade Tunnel (Part 3)| journal = The Engineer | date =28 June 1929 | title =The Cascade Tunnel : Great Northern Railway, U.S.A (No.III)| pages =698–700 | url=http://www.gracesguide.co.uk/images/b/b5/Er19290628.pdf | volume =147}}
* {{cite book |last=Haut |first=F.J.G.|title=The History of the Electric Locomotive |date=1969 |isbn=004-385042-1 |publisher=George Allen and Unwin Ltd |location=London |url=https://books.google.com/books?id=NyNSAAAAMAAJ}}
* {{Hidy-Great Northern|display-authors=1}}
* {{cite journal | first = Cary T. | last = Hutchinson | title = The electric system of the Great Northern railway company at Cascade tunnel | journal = Proceedings of the American Institute of Electrical Engineers | date = 1909 | volume = 28 | issue = 11 | pages = 1409–1447 | doi = 10.1109/PAIEE.1909.6660192 | s2cid = 51673934 | url = https://archive.org/details/Hutchinson1909Transactionsame52engigoog }}
* {{cite web |author=Legg, John F. |url=http://www.btinternet.com/~ucrs/ucrs/rl/rl470.html |title=UCRS-Reference (GN Stevens Pass) |accessdate=2005-02-25 |url-status=dead |archiveurl=https://web.archive.org/web/20050314190422/http://www.btinternet.com/~ucrs/ucrs/rl/rl470.html |archivedate=2005-03-14 }}
* {{cite book | last=Middleton | first=William D. | title = When the steam railroads electrified | year = 1974 | publisher=Kalmbach Books | isbn = 0-89024-028-0 }}
* {{cite book |last1=Roe |first1=JoAnn |title=Stevens Pass |date=1995 |publisher=The Mountaineers |location=Seattle, WA |isbn=0-89886-371-6}}
* {{cite book | last=Wood | first=Charles | first2=Dorothy |last2=Wood |title=The Great Northern Railway |date=1989-06-01 |publisher=Pacific Fast Mail |isbn=978-0-915713-19-6 }}
{{refend}}

== External links ==
{{Commons category}}
* [https://babel.hathitrust.org/cgi/pt?id=mdp.39015024546502&view=1up&seq=48 Scientific American n.s. v.137 1927.] Scientific American, July 1927 - America's Longest Tunnel.
* [http://digitalcollections.lib.washington.edu/cdm/search/collection/pickett/searchterm/construction%20tunnel/field/descri/mode/all/conn/and/cosuppress/ University of Washington Libraries Digital Collections&nbsp;– 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.
* [http://www.gngoat.org/east_portal.htm Cascade Tunnel # 15]&nbsp;— Pictures and details of the "Fanhouse" at the east portal of the tunnel
* [https://web.archive.org/web/20120215225757/http://www.vintageradioplace.com/ra/sametime080720.ram Radio Broadcast of the 1929 Cascade Tunnel Dedication]
*{{ citation |chapter-url=http://www.railwaywondersoftheworld.com/cascade-tunnel.html |chapter= Tunnelling against time |title=Railway Wonders of the World |year =1936 |pages=47–52 |editor-first=Clarence |editor-last=Winchester }} illustrated description of the construction of the second Cascade tunnel

{{Authority control}}

[[Category:Railroad tunnels in Washington (state)]]
[[Category:Great Northern Railway (U.S.) tunnels]]
[[Category:BNSF Railway tunnels]]
[[Category:Transportation buildings and structures in Chelan County, Washington]]
[[Category:Electric railways in Washington (state)]]
[[Category:Transportation buildings and structures in King County, Washington]]
[[Category:Tunnels completed in 1900]]
[[Category:Tunnels completed in 1929]]
[[Category:Railways with Zig Zags]]