Twin Peaks tunnel work to disrupt Metro service


A project to replace the aging rail tracks inside the 100-year old Twin Peaks Tunnel is about to finally start.

The San Francisco Municipal Transportation Agency posted a Feb. 7 project status update on its website that said crews will start work sometime in April. The construction will affect the more than 80,000 daily riders that pass through the tunnel because the work will require the shutdown of subway service between West Portal and Castro stations.

Transit officials are planning for five shutdowns that will last anywhere between 11 to 15 days, said Wahid Amiri, the project manager for the Twin Peaks Tunnel Improvements project. The transit agency said it plans to publish a finalized construction schedule soon. The original plan had called for 21 non-consecutive weekend shutdowns of the tunnel.

The SFMTA said it will run bus shuttles during the shutdown of the tunnel, which may require some Muni passengers to make transfers to other routes or to use BART.

Officials at the SFMTA had originally planned the start the of the Twin Peaks Tunnel project to coincide with a previous project which shutdown the entire Muni Metro system so that the transit agency could replace its radio system and blue light emergency phones in July 2015. The SFMTA completed that project in January 2016.

Amiri spoke to SFBay last Tuesday during the SFMTA’s Board of Director’s workshop meeting, saying there was a longer extensive outreach period with merchants, residents and with the contractor to figure out a workable construction schedule, which caused the delayed start.

Posted on the SFMTA website is a PDF file of the concerns from the West Portal neighborhood regarding the project.

Besides replacing the rail tracks between West Portal and Castro stations, which have not been replaced since 1975, crews will replace machines that operate track switches, make seismic upgrades to the abandoned Eureka Valley Station, improve structural support between West Portal and Forest Hill stations, make repairs to concrete walls, improve the fire suppression system at West Portal Station and replacing the tunnel’s drainage system.

Staging areas for the project have already been established by crews from NTK Construction. The SFMTA’s Board of Directors awarded the construction company the $33 million contract in April 2016.

Muni riders may have noticed now for months that rail tracks have been sitting along Junipero Serra Boulevard between Ocean Avenue and Sloat Boulevard, which is one of the staging areas.

The other staging area is on Market between Collingwood and Castro streets, the SFMTA said.

Bus Shuttle Service

The SFMTA said that its transit division is still finalizing plans for the affected train lines, but have posted an overview of how that plan might look like.

Trains will run on the K-Ingleside from St. Francis Circle to Balboa Park Station. Muni passengers who need head to downtown should take BART at the Balboa Park Station.

L-Taraval shuttle buses will run between Castro Station to the San Francisco Zoo every five minutes during the morning and evening peak commute times. During the midday, buses will run every eight to 10 minutes. Buses will stop at every regular L-Taraval stop from the zoo to 14th Avenue. From 14th Avenue, the buses will make one stop at Forest Hill Station and then will head to Castro Station.

The M-Ocean View shuttle buses will follow the same time pattern as the L-Taraval shuttle buses. The M shuttle buses will stop at all regular stops between Balboa Park Station and Vicente Street. From Vicente Street, the shuttle buses will head to Castro Station. The M shuttle buses will not stop at Forest Hill Station, according to the SFMTA.

A Forest Hill shuttle bus will also operate every 15 minutes between St. Francis Circle and Forest Hill station.

Muni passengers will not need to pay transit fares for riding any of the bus shuttles, but will need to pay for fares for any transfers to Muni trains, other bus routes and BART.

The public can read more about the Twin Peaks Tunnel project on the SFMTA’s website.

Jerold Chinn
Jerold Chinn is the San Francisco Bureau Chief of SFBay. A San Francisco native, he has spent a decade covering transportation in San Francisco. Send tips to or at Twitter @Jerold_Chinn.

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