| 词条 | Twin Peaks Tunnel | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 释义 |
|name = Twin Peaks Tunnel |image = Twin Peaks Tunnel.jpg |image_size = 300px |caption = Twin Peaks Tunnel at Forest Hill station |line = {{MUNI legend|K}}{{MUNI legend|L}}{{MUNI legend|M}}{{MUNI legend|T}}{{MUNI legend|S}} |location = San Francisco, California |coordinates = East portal: {{Coord|37|45|43|N|122|26|13|W|format=dms|display=inline|type:landmark_region:US-CA}} West portal: {{Coord|37|44|29|N|122|27|56|W|format=dms|display=inline|type:landmark_region:US-CA}} |system = Muni Metro |status = |start = Eureka Valley (closed) |end = West Portal Station |stations = 3 (2 open, 1 closed) |opened = {{start date and age|1918|2|3}} |close = |rebuilt = June 25 - August 24, 2018 |owner = San Francisco Municipal Transportation Agency |operator = San Francisco Municipal Railway |character = Underground subway tunnel for light rail/streetcar system |length = {{convert|11675|ft|m|abbr=on}}[1]{{rp|5}} |linelength = {{convert|2.27|mi|km|abbr=on}} |tracklength = |notrack = 2 |gauge = {{RailGauge|ussg}} (standard gauge) |el = Overhead lines, 600 V DC |speed = |hielevation = |lowelevation= |height = {{convert|25|ft|m|abbr=on}}[2] |grade = |map ={{Twin Peaks Tunnel}} }} The Twin Peaks Tunnel is a {{convert|2.27|mi|km|adj=on}} long[2] light rail/streetcar tunnel in San Francisco, California. The tunnel runs under the Twin Peaks and is used by the K Ingleside/T Third Street, L Taraval, M Ocean View, and S Shuttle lines of the Muni Metro system. The eastern entrance to the tunnel is located near the intersection of Market and Castro streets in the Castro neighborhood, and the western entrance is located at West Portal Avenue and Ulloa Street in the West Portal neighborhood. There are two stations along the tunnel, Forest Hill near the western end, and the now disused Eureka Valley near the eastern end. HistoryPlans for a tunnel extending from Market Street under Twin Peaks were first presented at the Merchants' Association banquet in May 1909; A. W. Scott Jr. spoke on the need for the tunnel to open up the western part of San Francisco to development, as "40,000 San Franciscans lived across the bay or in San Mateo county because of the lack of proper transportation in this city."[1] In April 1910, a committee named the Twin Peaks Convention was formed to plan the project, which would open the development of approximately one quarter of San Francisco's land area.[2] Competing proposalsIn July 1910 an architectural rendering was released of the eastern portal; the tunnel was initially envisioned as a two-story bore {{convert|1.5|mi|km}} long, carrying road traffic on the upper deck and rail traffic on the lower deck. Market Street would be extended southwest in a straight line across private property to connect to the eastern portal, to be located at the intersection of 19th and Douglass.[3] Initial estimates for the cost of the tunnel ranged from {{USD|1500000|1909|round=-6}} in 1909[1] to {{USD|3000000|1910|round=-6}} in 1910.[3] The Twin Peaks Tunnel and Improvement Convention released their report in August 1910 recommending a municipal bond to pay for the tunnel, whose costs would be recouped by the additional taxation of the land that would then be opened for development. Other options were considered and rejected, including a special assessment district or a long-term railroad lease.[4] The San Francisco Board of Supervisors approved a competing plan to build a longer tunnel under Twin Peaks in March 1912, continuing under Market to Valencia, which was seen as the foundation for a rapid transit system connecting the downtown Financial District with western San Francisco and the Peninsula.[5] This action was taken on the recommendation of noted tunnel expert Bion J. Arnold, who had submitted two preliminary reports in 1912, following up with a final report in March 1913. The 1913 report studied several alternative alignments and configurations, recommending construction of both the Twin Peaks Tunnel and what would become the Sunset Tunnel.[6]
In the 1913 report, Arnold primarily considered proposals No. 2 and No. 5B, concluding "I can recommend unqualifiedly {{sic}} the construction of a Twin Peaks Rapid Transit tunnel at the earliest possible date. In so doing, there will be brought within 30 minutes' running time of the business district, approximately 10,000 acres of new territory, 75% of which is suitable for residence land, that has been practically useless heretofore by reason of lack of adequate transportation thereto."[6] One of the key elements of proposal No. 5B was the creation of a new station along the tunnel, which is now present-day Forest Hill station (then called Laguna Honda station, at the intersection of Laguna Honda and Dewey Boulevard).[6][15] The San Francisco Call speculated the presence of a station at Laguna Honda meant the Geary line could be extended through Golden Gate Park.[7] A 1912 report by Arnold proposed that Laguna Honda would be a transfer point enabling passengers to move from Third and Market to Ocean Beach within 25 minutes on an express car, assuming a Seventh Avenue surface line was built.[8] {{OSM Location map|coord={{Coord|37.757|-122.446}} |float=right |zoom=13 |width=300 |height=270 |scalemark=20 |shape1=n-square |shape-color1=#f00 |shape-outline1=#fff |mark-size1=20 |mark-coord1 ={{Coord|37|45|43|N|122|26|13|W}} |mark-title1 =East Portal |mark-coord2 ={{Coord|37.759020|-122.439185}} |shape-color2 =#00f |mark-title2 =Proposed East Portal (1910, T.P. Tunnel Assoc.)[3] |mark-coord3 ={{Coord|37.772497|-122.422744}} |shape-color3 =#080 |mark-title3 =Proposed East Portal (1913, Arnold)[6] |mark-coord4 ={{Coord|37|44|29|N|122|27|56|W}} |shape4=n-circle |mark-title4 =West Portal |mark-coord5 ={{coord|37.74803|-122.45914|}} |shape5=n-circle |mark-title5 =Forest Hill / Laguna Honda |mark-coord6 ={{coord|37|45|42|N|122|26|17|W}} |mark-title6 =Eureka Valley |shape6=n-circle |shape-color6=#a00 |fullscreen-option=1 |caption=Twin Peaks Tunnel locations |auto-caption=1 }} At a proposed {{convert|16000|ft}} in length, Arnold's proposed tunnel would not be suitable for road traffic for lack of adequate ventilation. He also believed the straight extension of Market to 19th and Douglass was impractical, as it would require extensive earth moving and exceed 3% maximum grade.[6] It was on this basis the Twin Peaks Association of Improvement voiced their opposition to Arnold's plans in May 1912.[9] City Engineer M.M. O'Shaughnessy recommended terminating the tunnel at 17th and Market in February 1913, as he thought the Market Street Subway may need to be extended past Valencia, potentially to Third.[10] O'Shaughnessy's report endorsing Arnold's plan[11] was unanimously adopted by the Board of Supervisors in October 1913.[12][13] With the addition of {{convert|15000|acre}} of "the best residence property on the peninsula within 15 minutes of the business center of the city", the Call estimated the population of San Francisco would add 100,000 within three years and 200,000 within five.[14] Carl Larsen, a prominent resident of the rural western side of San Francisco, recommended shortening the tunnel proposed by Arnold by moving the western portal to Laguna Honda station, but O'Shaughnessy stated the resulting grade would be too steep.[15][16] Mayor James Rolph signed the Twin Peaks Tunnel Act in November 1913, rejecting the proposal for a shorter tunnel.[17] Construction and openingThe contract for tunnel construction was awarded on November 2, 1914 to the R.C. Storrie Company for {{US$|3372000|1914|round=-4}}[18]{{rp|5;7}} and work began on the Twin Peaks Tunnel in December 1914 with an estimated three-year construction schedule for the twin-track bore.[19] Construction was completed thirty-three months later.[20] Funding for the tunnel came from special assessment districts established at the eastern and western ends; the undeveloped western area, approximately {{convert|4000|acre}}, was responsible for 85% of tunnel costs.[18]{{rp|5}} {{multiple image| align = right | direction = vertical | caption_align = center | image1=Twin Peaks Tunnel (double tube flat top section, east end)2.svg |caption1="Double Tube Flat Top" | image2=Twin Peaks Tunnel (soft ground, west end).svg |caption2="Soft Ground" | footer_align = left | footer = Profile sections of Twin Peaks Tunnel. Most of the structure uses the "Soft Ground" arched profile, with the exception of the eastern end of the tunnel, which uses the "Double Tube Flat Top" section.}} The eastern approach to the tunnel was built along a parcel purchased by the city approximately {{convert|1800|ft}} long and {{convert|90|ft}} wide at the end of Market. This right-of-way was also later paved to connect Market with Portola.[18]{{rp|5}} As originally constructed, the total length of the tunnel is {{convert|11675|ft}} (including approaches) and the highest point of the tunnel is near Laguna Honda station. Sloping down from the peak at Laguna Honda, the tunnel has a maximum grade of 3% from west to east and 1.15% from east to west.[18]{{rp|5}} Excluding approaches, the tunnel is {{convert|8800|ft}} long.[21] The eastern {{convert|1665|ft|adj=on}} portion (with the exception of the {{convert|300|ft|adj=on}} long Eureka Valley station) of the tunnel uses a double-tube subway structure, and the remainder adopts an arched tube profile.[18]{{rp|5–6}} As designed, both sections provide {{convert|15|ft}} of vertical clearance above the top of the rail; each tube in the double-tube section is {{convert|14|ft}} wide, and the arched tube is {{convert|25|ft}} wide at its maximum.[18]{{rp|6}} The lunette space between the arched roof and flat ceiling of the tube was used as a duct to convey fresh air into the tunnel. One blower was mounted at the west end of the double-tube structure, and the other was at a ventilating shaft {{convert|110|ft}} deep, located {{convert|4600|ft}} east of the western portal. Excavation of the ventilating shaft required pumping {{convert|300000|gal|l}} of water per day after a horizontal drift at the bottom of the shaft struck water-bearing sand.[18]{{rp|7}} Laguna Honda, West Portal, and Eureka Valley stations were constructed using cut-and-cover methods. Laguna Honda station is approximately {{convert|70|ft}} below grade.[18]{{rp|7}} The tunnel was excavated simultaneously from the open cuts at each end; initial excavation sank three drifts (one at each side along the springline, and one at the crown of the tunnel). A fourth drift was added at the centerline bottom of the tunnel to facilitate drainage of the ground at the western end.[18]{{rp|7–8}} The two crews first "holed through" and connected their excavations near Laguna Honda station on April 5, 1917, {{convert|6100|ft}} from the east portal and {{convert|5900|ft}} from the west.[20] Several notable accidents occurred during the construction of the tunnel:
Dedication ceremonies were held at each portal on July 14, 1917. Mayor Rolph and several other dignitaries, including former Mayor P. H. McCarthy spoke at the east portal, beginning at 2:00 p.m.; after the remarks, hundreds of people walked through the tunnel to the west portal, and Judge E. P. Shortall was the first of the pedestrians to arrive. At the west portal, Mayor Rolph spoke again and a ceremonial silver spike was driven by O'Shaughnessy and Rolph to mark the start of construction of the Twin Peaks Railway.[27] The inaugural trip through the tunnel occurred on December 31, 1917.[28] The tunnel was opened to revenue service on February 3, 1918,[29] and was the world's longest tunnel for street railway traffic at the time.[30][31] Mayor Rolph served as the motorman for the first revenue trip, and most of the paying passengers were City Supervisors, wives, and invited guests. The trip through the tunnel took seven minutes.[21] Incorporation into Muni Metro{{multiple image| align = left | direction = vertical | caption_align = center | total_width = 220 | image1=B&EN v16 no 24 fig06 pg08 (1916-06-24) Arch Section West Portal.jpg |caption1=(1916) | image2=More on That MUNI Short Turn at West Portal -- 3 Photos (26931188596).jpg |caption2=(1967) | image3=Exterior panorama of West Portal station, June 2017.jpg |caption3=(2017) | footer_align = left | footer = West Portal station, the western tunnel entrance, in 1916 (during construction), 1967 (before the conversion to light rail), and present-day (2017)}} The tunnel was built sloping downwards at the east end, anticipating future expansion to a tunnel under Market Street per Arnold's plan.[8][32] A technical report was commissioned by the city in 1960 to study possible rapid transit routes. This recommended that the initial line linking BART from a transbay tunnel to Daly City be routed through Twin Peaks Tunnel.[33] BART's 1961 plan did not include the tunnel connection on Market Street.[34] When the Market Street Subway was built in the late 1970s, it was connected to the Twin Peaks Tunnel to be used by the K Ingleside, L Taraval and M Ocean View lines. These services were spared from conversion to trolleybus by virtue of their use of Twin Peaks Tunnel. The Eureka Valley station was closed and was functionally replaced by Castro Street Station. This combined subway line was the impetus for transitioning the system to light rail and served as the basis of Muni Metro. The original eastern entrance to the tunnel in the middle of Market Street at Castro was removed and new entrances were placed on the sides of the street further up the block, though no Metro or streetcar lines use them in regular service (they were used during construction of the Market Street subway and are occasionally used in non-revenue service such as rerouting trains around construction projects). Instead, trains continue directly from the Market Street Subway into the tunnel without going above ground. Forest Hill and Eureka Valley stations were originally constructed with low platforms, as streetcars of that era had steps to load passengers from street level. However, the six new Market Street Subway stations were built with high-level platforms for speedier level boarding onto the new Boeing LRVs. West Portal station, which was originally a surface stop outside of the tunnel's western entrance, was rebuilt as a high-platform station located just inside of the entrance. With Eureka Valley station permanently closed, Forest Hill was left as the only low-platform station on the Muni Metro subway. Muni soon modified the station with high-level platforms, completing that project in 1985.[35] Rail replacement projectAround 2014, with the tunnel nearing a century of continuous use, Muni began planning a major track replacement project in the tunnel, which would be the first since 1975.[36] The project includes the replacement of all rails and ties in the tunnel with new rails directly fixed to concrete pads, the installation of two pairs of crossovers (one near West Portal, the other just east of Forest Hill), replacement of existing switches to the unused eastern portals, a structural refit of the former Eureka Valley area, replacement of the overhead wires, and a number of other repairs and improvements.[37] The work will lift an existing {{convert|25|mph}} speed limit through the tunnel. Noise reduction techniques from a similar project on the Sunset Tunnel in 2016 will be used.[38] The construction contract was awarded on April 5, 2016.[36] The project was originally planned to begin in late 2016, but has suffered a series of delays. It was delayed from April 2017 to mid-2017 (with a completion date of mid-2018) in March 2017 to allow for "additional technical analysis" of the tunnel.[39] In June 2017, the project was indefinitely delayed after the construction contract was terminated.[40] Muni and the contractor could not agree on a new schedule and costs to minimize disruptions to riders; the project duration increased from 460 days to 807 days and the cost to $48 million, and Muni staff recommended the contract be terminated.[41] The SFMTA released a Request for Qualifications in October 2017, and bidding opened for the $35.5 million project in November.[42][43] The closure began on June 25, 2018, and lasted until August 24.[44] During the closure, Muni Metro was short turned at Castro station; the surface section of the K Ingleside was through-routed with the J Church, while the L Taraval and M Ocean View were replaced by buses.[45] Systemwide delays during the summer of 2018 resulted from a combination of the tunnel shutdown and decreased qualified driver availability, which in turn was attributed to the rollout of LRV4s (requiring driver training), and contract issues.[46] Refurbishment work was temporarily suspended after a signal technician was fatally crushed by a steel beam on August 10.[47][48] The technician was an employee of Shimmick Construction, the firm contracted to handle the refurbishment; Shimmick had been cited for serious and willful safety violations on an unrelated job in 2011 by Cal/OSHA but neglected to disclose those violations during the bidding for the Twin Peaks Tunnel job.[49] Muni was also criticized for inadequate notice of service degradation to bus lines during the closure, since buses were pulled off regular routes to substitute for trains,[50] and for the death during the project.[51] The completion of the project allowed for the permanent use of two-car trains on the K/T lines.[52] References1. ^1 {{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19090528.2.5 |title=Mayor's tactful speech blasts Redding's hopes |date=28 May 1909 |newspaper=San Francisco Call |accessdate=23 July 2018}} 2. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19100806.2.74 |title=Twin Peaks' Tunnel Convention's Work |date=6 August 1910 |newspaper=San Francisco Call |accessdate=23 July 2018}} 3. ^1 2 {{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19100709.2.64.2 |title=Plans being made for building of big tube |date=9 July 1910 |newspaper=San Francisco Call |accessdate=23 July 2018}} 4. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19100820.2.58.2 |title=Convention solves engineering problem |date=20 August 1910 |newspaper=San Francisco Call |accessdate=23 July 2018}} 5. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19120323.2.113.2 |title=Building of Twin Peaks Tunnel assured by action of Supervisors |date=23 March 1912 |newspaper=San Francisco Call |accessdate=23 July 2018}} 6. ^1 2 3 4 5 {{cite report |url=https://archive.org/details/reportonimprovem1913arno |title=Report on the Improvement and Development of the Transportation Facilities of San Francisco |chapter=11. Market Street extension tunnel under Twin Peaks |pages=225–270 |author=Arnold, Bion J. |date=March 1913 |accessdate=17 April 2018}} 7. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19120727.2.143.9 |title=Geary Car Line may be extended |date=27 July 1912 |newspaper=San Francisco Call |accessdate=24 July 2018}} 8. ^1 {{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19121008.2.97 |title=Subway Express Under Twin Peaks for 25 Minute Dash to Beach: Arnold Devises Clever Project to Solve 1915 Traffic Problem |date=8 October 1912 |newspaper=San Francisco Call |accessdate=27 July 2018}} 9. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19120508.2.59 |title=Arnold's Twin Peaks Tunnel plan opposed |date=8 May 1912 |newspaper=San Francisco Call |accessdate=24 July 2018}} 10. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19130225.2.35 |title=Twin Peaks Tunnel to start on 17th Street |date=25 February 1913 |newspaper=San Francisco Call |accessdate=24 July 2018}} 11. ^{{cite report |url=https://catalog.hathitrust.org/Record/100154822 |title=Specifications for the construction of a tunnel and appurtenances under Twin Peaks |author=O'Shaughnessy, M.M. |date=July 1913 |publisher=Department of Public Works, City and County of San Francisco, California |accessdate=24 July 2018}} 12. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19131025.2.84 |title=Twin Peaks $4,000,000 Tunnel means a great forward step for city |date=25 October 1913 |newspaper=San Francisco Call |accessdate=24 July 2018}} 13. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19131022.2.60 |title=City in Position To Proceed With Twin Peaks Tunnel |date=22 October 1913 |newspaper=San Francisco Call |accessdate=24 July 2018}} 14. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19130927.2.121 |title=Population to be increased by tunnel |date=27 September 1913 |newspaper=San Francisco Call |accessdate=24 July 2018}} 15. ^1 {{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19131106.2.43 |title=Shorter Twin Peaks Tunnel Investigated |date=6 November 1913 |newspaper=San Francisco Call |accessdate=24 July 2018}} 16. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19130920.2.52 |title=Twin Peaks Tunnel, Says City Engineer, Can Not Be Reduced |date=20 September 1913 |newspaper=San Francisco Call |accessdate=24 July 2018}} 17. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SFC19131107.2.170 |date=7 November 1913 |title=Mayor Signs Twin Peaks Tunnel Act |newspaper=San Francisco Call |accessdate=24 July 2018}} 18. ^1 2 3 4 5 6 7 8 9 {{cite journal |url=https://archive.org/stream/buildingengineer1616cont#page/n868/mode/1up |title=Method and Progress of Construction of the Twin Peaks Tunnel In San Francisco, Cal. |author=Glick, L. |date=21 June 1916 |journal=Building and Engineering News |pages=5–13 |volume=16 |number=24 |accessdate=24 July 2018}} 19. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=RDP19141229.2.50 |title=Frisco tunnel has begun |date=29 December 1914 |newspaper=Riverside Daily Press |accessdate=24 July 2018}} 20. ^1 {{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SU19180901.2.219 |title=Log of a Motor Truck Tells Story of Great Performance on Long, Hard Drive |date=1 September 1918 |newspaper=Sacramento Union |accessdate=26 July 2018}} 21. ^1 {{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SN19180209.2.103 |title=New Car Speeds Through Picturesque Tunnel With the Mayor and President of Board of Public Works as Crew |date=9 February 1918 |newspaper=Sausalito News |accessdate=26 July 2018}} 22. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=LAH19150410.2.86 |title=8 Men Buried in Tunnel Collapse |agency=Pacific News Service |date=10 April 1915 |newspaper=Los Angeles Herald |accessdate=26 July 2018}} 23. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SBS19150411.1.1 |title=One Killed, a Dozen Injured When Street Tunnel Caves In |date=11 April 1915 |newspaper=San Bernardino Sun |accessdate=26 July 2018}} 24. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=RDP19151129.2.17 |title=Twin Peaks Tunnel fire |date=29 November 1915 |newspaper=Riverside Daily Press |accessdate=26 July 2018}} 25. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=RDP19170216.2.43 |title=Delayed blast kills four |date=16 February 1917 |newspaper=Riverside Daily Press |accessdate=26 July 2018}} 26. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=RDP19170228.2.9 |title=Damage settlement was surely easy |date=28 February 1917 |newspaper=Riverside Daily Press |accessdate=26 July 2018}} 27. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=MG19170721.2.22 |title=Crowd applauds mayor as he declares two-mile bore open |date=21 July 1917 |newspaper=Mariposa Gazette |accessdate=26 July 2018}} 28. ^{{cite journal |title=First Car Through Twin Peaks Tunnel |journal=Electric Railway Journal |date=19 January 1918 |volume=51 |page=151 |url=https://library.si.edu/digital-library/book/electricrailway511918newy |accessdate=23 July 2018}} 29. ^1 2 {{cite web |url = http://www.sfgenealogy.com/sf/history/hgtun.htm |title = San Francisco History - City's Tunnels |accessdate = July 14, 2008 |last = Wallace |first = Kevin |date = March 27, 1949 |publisher = San Francisco Chronicle }} 30. ^{{Cite news |url=http://www.sfgate.com/bayarea/article/Twin-Peaks-tunnel-opens-3252492.php |title=Twin Peaks tunnel opens |date=February 4, 2009 |work=San Francisco Chronicle |access-date=February 1, 2018}} 31. ^{{cite news |url=https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SN19180202.2.19 |title=Cars run through Twin Peaks |date=2 February 1918 |newspaper=Sausalito News |accessdate=26 July 2018}} 32. ^{{cite web |last1=Callwell |first1=Robert |title=Transit in San Francisco A Selected Chronology, 1850 - 1995 |url=https://archives.sfmta.com/cms/rhome/documents/TransitinSanFrancisco-CallwellChronologyweb.pdf |website=SFMTA.com |publisher=San Francisco Municipal Railway |accessdate=24 July 2018}} 33. ^{{cite web |url=https://catalog.hathitrust.org/Record/003502850 |title=A Plan for Rapid Transit in San Francisco Consonant with the Bay Area Rapid Transit System |date=19 May 1960 |author1=De Leuw, Cather & Company |publisher=The Transportation Technical Committee of the Mayor's Transportation Council, City of San Francisco |accessdate=10 January 2018}} 34. ^{{cite web |title=Rapid Transit for the San Francisco Bay Area |url=http://libraryarchives.metro.net/DPGTL/bart/1961-parsons-engineering-report-to-sf-bart-district.pdf |website=LA Metro Library |publisher=Parsons Brinkerhoff / Tudor / Bechtel |accessdate=21 July 2018}} 35. ^{{cite book |url=https://archive.org/stream/munimetroturnaro1989unit#page/n63/mode/2up |page=1-2 |chapter=Chapter 1 |title=Muni Metro Turnaround Project: Final Enivironmental Impact Statement |publisher=United States Department of Transportation Urban Mass Transportation Administration |via=Internet Archive |date=August 1989}} 36. ^1 {{cite press release |url=https://www.sfmta.com/news/project-updates/twin-peaks-tunnel-contract-awarded |title=Twin Peaks Tunnel Contract Awarded |date=April 28, 2016 |publisher=San Francisco Municipal Transportation Agency}} 37. ^{{cite web |url=https://www.sfmta.com/sites/default/files/projects/2015/2015-008803ENV%20-%20SFMTA%20-%20Twin%20Peaks%20Tunnel%20Project_CatEx.pdf |title=CEQA Categorical Exemption Determination |date=February 13, 2015 |publisher=San Francisco Municipal Transportation Agency |pages=5-6 |author=San Francisco Planning Department}} 38. ^{{cite web |url=https://www.sfmta.com/projects-planning/projects/twin-peaks-tunnel-trackway-improvements |title=Twin Peaks Tunnel Improvements |accessdate=November 30, 2017 |publisher=San Francisco Municipal Transportation Agency}} 39. ^{{cite press release |url=https://www.sfmta.com/news/project-updates/twin-peaks-tunnel-construction-held-until-summer |title=Twin Peaks Tunnel Construction Held Until Summer |date=March 16, 2017 |publisher=San Francisco Municipal Transportation Agency}} 40. ^{{cite press release |url=https://www.sfmta.com/news/project-updates/twin-peaks-tunnel-construction-delayed |title=Twin Peaks Tunnel Construction Delayed |date=June 6, 2017 |publisher=San Francisco Municipal Transportation Agency}} 41. ^{{cite news |url=https://sfbay.ca/2018/01/16/years-of-delay-haunt-muni-tunnel-projects/ |title=Years of delay haunt Muni tunnel projects |newspaper=SFBay |date=January 16, 2018 |first=Jerold |last=Chinn}} 42. ^{{cite web |url=http://mission.sfgov.org/OCABidPublication/BidDetail.aspx?K=12415 |title=Bid Document |publisher=City and County of San Francisco |date=October 17, 2017}} 43. ^{{cite web |url=http://mission.sfgov.org/OCABidPublication/BidDetail.aspx?K=12516 |title=Bid Document |publisher=City and County of San Francisco |date=November 2017}} 44. ^{{cite news|url=https://www.sfchronicle.com/bayarea/article/Muni-s-Twin-Peaks-Tunnel-reopens-to-the-relief-13182708.php|title=Muni’s Twin Peaks Tunnel reopens to the relief of frustrated passengers|first=Lauren|last=Hernández|work=San Francisco Chronicle|date=August 25, 2018|accessdate=August 25, 2018}} 45. ^{{cite web |url=https://www.sfmta.com/projects/twin-peaks-tunnel-improvements-0 |title=Twin Peaks Tunnel Improvements |publisher=San Francisco Municipal Transportation Agency |date=June 25, 2018 |archiveurl=https://web.archive.org/web/20180626232234/https://www.sfmta.com/projects/twin-peaks-tunnel-improvements-0 |archivedate=June 26, 2018}} 46. ^{{cite news |url=http://www.sfexaminer.com/muni-suffering-major-citywide-service-gaps-due-operator-shortage/ |title=Muni suffering major citywide service gaps due to operator shortage |first=Joe Fitzgerald |last=Rodriguez |date=July 26, 2018 |newspaper=San Francisco Examiner |accessdate=27 August 2018}} 47. ^{{cite news |url=http://www.sfexaminer.com/sf-twin-peaks-tunnel-construction-resume-accidental-death-worker/ |title=Twin Peaks Tunnel construction resumes after accidental death of worker |first=Michael |last=Barba |date=August 12, 2018 |newspaper=San Francisco Examiner |accessdate=August 27, 2018}} 48. ^{{cite news |url=http://www.sfexaminer.com/worker-fatally-struck-steel-beam-muni-tunnel-idd/ |title=Technician killed by beam in Twin Peaks Tunnel was working with stepson |first=Michael |last=Barba |date=August 13, 2018 |newspaper=San Francisco Examiner |accessdate=August 27, 2018}} 49. ^{{cite news |url=http://www.sfexaminer.com/sfmta-head-defends-decision-hire-company-muni-tunnel-worker-death/ |title=SFMTA head defends choice of contractor in Twin Peaks tunnel death |first=Michael |last=Barba |date=August 21, 2018 |newspaper=San Francisco Examiner |accessdate=August 27, 2018}} 50. ^{{cite web |url=https://missionlocal.org/2018/08/muni-meltdown-2018-our-transit-service-failed-to-plan-and-thereby-planned-to-fail/ |title=Muni meltdown 2018: Our transit service failed to plan — and, thereby, planned to fail |first=Joe |last=Eskenazi |date=August 6, 2018 |website=Mission Local |accessdate=27 August 2018}} 51. ^{{cite news|url=https://www.sfgate.com/bayarea/article/Breed-blasts-Muni-chief-over-delays-background-13169518.php|title=SF mayor Breed blasts Muni chief over delays, background checks and scooter permitting|last=Swan|first=Rachel|date=August 20, 2018|accessdate=August 25, 2018|work=San Francisco Chronicle}} 52. ^{{cite press release |url=https://www.sfmta.com/blog/two-car-trains-now-permanent-kt-line |title=Two-Car Trains Now Permanent on K/T Line |publisher=San Francisco Municipal Transportation Agency |first=Bonnie Jean |last=von Krogh |date=August 24, 2018}} External links{{commons category}}
7 : Muni Metro|Railroad tunnels in California|Tunnels in San Francisco|Tunnels completed in 1918|1918 establishments in California|Castro District, San Francisco|Underground rapid transit in the United States |
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