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Twin Peaks Tunnel
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Twin Peaks Tunnel
The Twin Peaks Tunnel is a 2.27-mile-long (3.65 km) light rail/streetcar tunnel in San Francisco, California. The tunnel runs under Twin Peaks and is used by the K Ingleside, L Taraval, M Ocean View and S Shuttle lines of the Muni Metro system.
The eastern entrance to the tunnel is located at the west end of the Market Street subway, 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, named for the tunnel. There are three stations along the tunnel: West Portal at the western entrance, Forest Hill near the middle, and the now disused Eureka Valley near the eastern end.
Plans 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." 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.
In July 1910, an architectural rendering was released of the eastern portal; the tunnel was initially envisioned as a two-story bore 1.5 miles (2.4 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. Initial estimates for the cost of the tunnel ranged from US$1,500,000 (equivalent to $54,000,000 in 2025) in 1909 to US$3,000,000 (equivalent to $104,000,000 in 2025) in 1910.
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.
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. This action was taken on the recommendation of noted tunnel expert Bion J. Arnold, who had submitted two preliminary reports in 1912 and followed 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.
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." 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). The San Francisco Call speculated the presence of a station at Laguna Honda meant the Geary line could be extended through Golden Gate Park. 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.
At a proposed 16,000 feet (4,900 m) 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. It was on this basis that the Twin Peaks Association of Improvement in 1912 voiced their opposition to Arnold's plans. In February 1913 City Engineer M.M. O'Shaughnessy recommended terminating the tunnel at 17th and Market, as he thought the Market Street subway may need to be extended past Valencia, potentially to Third. O'Shaughnessy's report, endorsing Arnold's plan, was unanimously adopted by the Board of Supervisors in October 1913. With the addition of 15,000 acres (6,100 ha) 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.
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Twin Peaks Tunnel
The Twin Peaks Tunnel is a 2.27-mile-long (3.65 km) light rail/streetcar tunnel in San Francisco, California. The tunnel runs under Twin Peaks and is used by the K Ingleside, L Taraval, M Ocean View and S Shuttle lines of the Muni Metro system.
The eastern entrance to the tunnel is located at the west end of the Market Street subway, 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, named for the tunnel. There are three stations along the tunnel: West Portal at the western entrance, Forest Hill near the middle, and the now disused Eureka Valley near the eastern end.
Plans 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." 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.
In July 1910, an architectural rendering was released of the eastern portal; the tunnel was initially envisioned as a two-story bore 1.5 miles (2.4 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. Initial estimates for the cost of the tunnel ranged from US$1,500,000 (equivalent to $54,000,000 in 2025) in 1909 to US$3,000,000 (equivalent to $104,000,000 in 2025) in 1910.
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.
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. This action was taken on the recommendation of noted tunnel expert Bion J. Arnold, who had submitted two preliminary reports in 1912 and followed 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.
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." 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). The San Francisco Call speculated the presence of a station at Laguna Honda meant the Geary line could be extended through Golden Gate Park. 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.
At a proposed 16,000 feet (4,900 m) 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. It was on this basis that the Twin Peaks Association of Improvement in 1912 voiced their opposition to Arnold's plans. In February 1913 City Engineer M.M. O'Shaughnessy recommended terminating the tunnel at 17th and Market, as he thought the Market Street subway may need to be extended past Valencia, potentially to Third. O'Shaughnessy's report, endorsing Arnold's plan, was unanimously adopted by the Board of Supervisors in October 1913. With the addition of 15,000 acres (6,100 ha) 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.
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