Why Twin Peaks Tunnel Will Be Closed This Weekend

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Thursday, June 20, 2024

A worker inspects infrastructure in the Twin Peaks Tunnel

A worker inspects infrastructure in Twin Peaks Tunnel. 

For over a century, Twin Peaks Tunnel has helped people zip across the heart of San Francisco. And with all these years of service under its belt, the tunnel needs some TLC to keep up with the demands of time and the Muni system. 

We recently completed a comprehensive structural inspection of the tunnel. Rest assured, the inspection found it’s safe for both Muni passengers and workers.  

But there has been some distortion to the tunnel over the years. That’s why we’re taking the proactive step to rehabilitate and repair two areas in the tunnel to ensure it stays safe.  

The work kicks off this weekend with the first of three tunnel closures:

  • Saturday, June 22 – Sunday, June 23
  • Saturday, July 20 – Sunday, July 21
  • Thursday, August 22 – Thursday, August 29 

During construction, the subway will operate from Embarcadero to Castro. We’ll run bus shuttles from the Castro and Church stations to serve the K, L and M lines. 

We know any interruption to regular service can be frustrating. We are doing everything we can to keep the shutdowns short. We’re running S Shuttle trains, and bus shuttles will come as often as regular service -- or more often!  

Here's what to know during the three tunnel closures so you can keep counting on Muni:  

  • West Portal and Forest Hill stations will be closed all day. Please use K Bus, L Bus or M Bus shuttles at street level.
  • M Buses and K Buses will run between Balboa Park and Church Station. They will serve the West Portal, Forest Hill, Castro and Church stations. All regular M Bus and K Bus stops between West Portal and Balboa Park will be served.
  • L Buses will be extended to run between SF Zoo and Church Station. They will serve the West Portal, Forest Hill, Castro and Church stations. All regular L Bus stops between West Portal and SF Zoo will be served.
  • S Shuttle trains will run service between the Castro and Embarcadero stations. They will serve the Embarcadero, Montgomery, Powell, Civic Center, Van Ness, Church and Castro stations. At Castro Station, board from the Castro Eastbound platform.
  • J, N and T trains will run as usual. To access K, L or M buses from these lines, transfer to the S Shuttle. You can exit at either Church or Castro station to board a K Bus, L Bus or M Bus.
  • Real-Time arrival predictions will be available from your favorite app, like Muni Mobile, Google Maps, Apple Maps and Transit App. For some trips downtown, it may be faster to travel using BART. 

During the June and July tunnel closures, crews will work to determine the most effective materials and repairs methods. We’ll then complete the full repairs in August. We’re consolidating other projects with this construction to get more done and limit tunnel closure time.  

We’re also coordinating with the San Francisco Unified School District. They are planning an improvement project at West Portal Elementary to begin when the tunnel work is complete. 

Once the repairs are finished this summer, we’ll continue to monitor and inspect the tunnel. And we’ll be improving the tunnel even more over the next 5-10 years to keep it safe and reliable for decades to come.