Flathead Tunnel

{{Short description|Rail tunnel in Montana, United States}}

{{Use mdy dates|date=April 2025}}

{{Infobox tunnel

|name = Flathead Tunnel

|image = File:Eastbound Empire Builder Enters Flathead Tunnel - panoramio.jpg

|caption = Eastbound Empire Builder enters Flathead Tunnel

|line = Kootenai River Subdivision (Northern Transcon)

|location = Lincoln County, Montana, USA

|coordinates = {{coord|48.5508192|-114.9561739|region:US_type:landmark|format=dms|display=inline,title}}

|system = BNSF

|status =

|start =

|end =

|stations =

|startwork = May 12, 1966{{rp|2}}

|opened = November 7, 1970

|close =

|owner = BNSF Railway

|operator =

|traffic = 40 trains daily ({{as of|2022|lc=y}})

|character =

|construction = blasted with cut and cover portals

|length = {{convert|36955|ft|mi km|abbr=on|1}}{{rp|2}}

|linelength =

|tracklength =

|notrack = Single

|gauge = {{track gauge|ussg|allk=on}}

|el =

|speed =

|hielevation = {{convert|3720|ft|m|abbr=on}}

|lowelevation = {{convert|3620|ft|m|abbr=on}}

|height =

|grade =

}}

The Flathead Tunnel is a {{convert|7|mi||adj=mid|-long}} railroad tunnel in the Rocky Mountains of northwest Montana near Trego, approximately {{convert|28|mi}} west of Whitefish. Located on the BNSF Railway's Kootenai River Subdivision, it is the second-longest railroad tunnel in the United States after the Cascade Tunnel.{{cite news |url=https://digital.library.unt.edu/ark:/67531/metadc170843/m2/1/high_res_d/metadc67154.pdf |title=The Flathead Tunnel: A Geologic, Operations, and Ground Support Study, Burlington Northern Railroad, Salish Mountains, Montana |date=1974 |publisher=Spokane Mining Research Center |access-date=2 August 2021 |agency=U.S. Bureau of Mines |website=University of North Texas Library}}{{cite news |last1=Franz |first1=Justin |title=BNSF to Improve Flathead Tunnel as Part of Annual Capital Program |url=https://flatheadbeacon.com/2018/02/13/bnsf-improve-flathead-tunnel-second-longest-rail-portal-u-s-part-annual-capital-program/ |accessdate=12 October 2018 |work=Flathead Beacon |date=13 February 2018}} It is ultimately named after the Bitterroot Salish, also known as the Flathead.

The tunnel was constructed for the Great Northern Railway by the Walsh Construction Company and S.J. Groves and Sons (collectively known as Walsh–Groves) at a cost of nearly $44 million (equivalent to ${{Inflation|US-GDP|44|1966}} million in {{Inflation/year|US-GDP}}).{{cite web |last1=Weber |first1=Jeremy |title=Trego railroad tunnel major construction feat |url=https://dailyinterlake.com/news/2022/jan/16/trego-railroad-tunnel-major-construction-feat/ |publisher=Daily Inter Lake |access-date=February 20, 2023 |archive-url=https://web.archive.org/web/20220519023928/https://dailyinterlake.com/news/2022/jan/16/trego-railroad-tunnel-major-construction-feat/ |archive-date=May 19, 2022 |location=Kalispell, Montana |language=en |date=January 16, 2022}} It is part of a {{convert|60|mi|adj=on}} rerouting of the Great Northern Hi-Line that became a necessity due to construction of Libby Dam and subsequent creation of Lake Koocanusa.{{cite news |last=Floyd |first=Doug |date=August 25, 1975 |title=Dam gets Ford's praise, but it's not energy key |pages=1, 3 |work=Spokane Daily Chronicle |location=(Washington) |url=https://news.google.com/newspapers?id=gU9OAAAAIBAJ&sjid=zPgDAAAAIBAJ&pg=2860%2C1948115}}

Work began on May 12, 1966. Drilling was completed on June 21, 1968 when President Lyndon B. Johnson ceremoniously triggered a final explosion from a circuit connected via telephone to the White House.{{cite news |title=President Presses Button |url=https://newspaperarchive.com/havre-daily-news-jun-24-1968-p-11/ |work=Havre Daily News |date=June 24, 1968 |location=Havre, Montana |page=11}}{{cite web |last1=Weber |first1=Jeremy |title=Stories from Trego tunnel deviate from historical record |url=https://dailyinterlake.com/news/2022/may/22/stories-trego-tunnel-deviate-historical-record/ |publisher=Daily Inter Lake |access-date=February 20, 2023 |archive-url=https://web.archive.org/web/20220522093436/https://dailyinterlake.com/news/2022/may/22/stories-trego-tunnel-deviate-historical-record/ |archive-date=May 22, 2022 |location=Kalispell, Montana |language=en |date=May 22, 2022}}

Finishing work continued for the following two years, and the tunnel, along with the entire rerouted rail line it is a part of, opened on November 1, 1970. An opening ceremony was held on November 7, 1970 and included the passage of the first official train through the tunnel, a 21-car passenger special carrying 1,200 area residents who were offered the opportunity to travel a circular route from Libby and back on both the new and old rail lines.{{cite news |title=Railroad News Photos |work=Trains |publisher=Kalmbach Publications |date=February 1971 |page=12}}{{cite news |title=Fine Train Program |url=https://newspaperarchive.com/kalispell-daily-inter-lake-nov-13-1970-p-4/ |work=Daily Inter Lake |date=November 13, 1970 |location=Kalispell, Montana |page=4}}

Official records indicate that two people were killed in two separate incidents during construction, both occurring after drilling was complete.

{{As of|2022}} the tunnel is used by about 40 freight trains each day as well as Amtrak's Empire Builder. Maximum speed through the tunnel is {{convert|50|mph}}.{{cite magazine|last=Kelly|first=Bruce|title=FLATHEAD TUNNEL AT 50|magazine=Trains|pages=30–33|issue=February 2021|publisher=Kalmbach Media}} The north portal contains a ventilation system to clear the tunnel of diesel locomotive exhaust and provide cooling air to eastbound locomotives, as there is an uphill grade heading eastbound.{{cite news |title=Tunnel Test Functions Well |url=https://newspaperarchive.com/kalispell-daily-inter-lake-oct-01-1970-p-1/ |work=Daily Inter Lake |date=October 1, 1970 |location=Kalispell, Montana |page=1}}{{cite web |last1=Weber |first1=Jeremy |title='Tunnel rats' and an engineering marvel |url=https://dailyinterlake.com/news/2022/jan/16/tunnel-rats-and-engineering-marvel/ |publisher=Daily Inter Lake |access-date=February 20, 2023 |archive-url=https://web.archive.org/web/20220519032435/https://dailyinterlake.com/news/2022/jan/16/tunnel-rats-and-engineering-marvel/ |archive-date=May 19, 2022 |location=Kalispell, Montana |language=en |date=January 16, 2022}}