SFMTA Sets Dates for Twin Peaks Tunnel Closure

The 106-year-old Twin Peaks Tunnel will close for a weekend in June and another July before an eight-day closure in August.

Construction workers in the tunnel.
SFMTA will perform repairs on the Twin Peak Tunnel this summer. | Courtesy SFMTA

The 106-year-old Twin Peaks Tunnel is set for closure during a weekend in June and July before an eight-day closure in August to make scheduled repairs inside the tunnel.

Transit officials said Tuesday that the tunnel will close on the weekend of June 22-23 and July 20-21 while the eight-day closure will happen from Aug. 22-29. During the closure, there will be no train service from West Portal and Forest Hill stations and instead require Muni Metro K Ingleside and M Ocean View passengers to take shuttle buses.

K and M buses will run from Balboa Park to Church, while making stops at West Portal, Forest Hill, Castro and Church. L Taraval buses will also extend their route to serve West Portal, Forest Hill, Castro and Church. S Shuttle trains will run during the closures between Castro and Embaracsdero stations.

Other rail lines such as the J Church, N Judah and T Third will run normally during the closures, the transportation agency said.

The San Francisco Municipal Transportation Agency hired the engineering firm HNTB to inspect the old tunnel. HNTB recently released its findings and found distortion in the tunnel that is causing leaks and various cracks throughout the tunnel.

During the summer closure, the transportation agency will work on strengthening the tunnel’s ceiling in two sections by installing tie rods and filling areas with grout behind the tunnel’s lining where soil is loose.

Transit officials said Tuesday at the agency’s board meeting that the subway is safe for passengers and SFMTA workers.

Amanda Eaken and Janet Tarlov, who sit on the transportation agency’s board, noted that the August dates coincide with the first week when public school students return from the summer recess. Tarlov told staff to pay extra attention to students who may be attending a new school and adapting to a new commute.

The SFMTA said they are coordinating its project schedule with the San Francisco Unified School District which will also begin project construction at West Portal Elementary School, which sits atop the tunnel.

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