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Twin Peaks Tunnel Inspection Project

Project Introduction

As part of an ongoing Twin Peaks Tunnel Inspection Project, SFMTA will complete a detailed structural inspection of the over two-mile-long Twin Peaks Tunnel. The inspection will require close up, in-person visual inspection as well as non-destructive testing.

This work requires significant preparation including de-energization of the overhead lines, shutdown of the track, staging of tools and equipment, mobilization of trackside equipment, and up-close inspection of the tunnel ceiling that is will be performed during non-revenue hours. Multiple teams will work around the clock to complete the work. Further inspections will be scheduled at a later date and may also require service changes.


SFMTA will close the Twin Peaks Tunnel between Castro and West Portal Stations on Saturday, April 15 and Sunday, April 16 to complete the detailed ceiling inspection. During the closure from 8 a.m. April 15 until midnight April 16, train service for the K Ingleside, L Taraval Bus, and M Ocean View lines will be modified. See Transit Service Plan section below for alternative service description. 

Transit Service Plan

  • Forest Hill and West Portal stations will be closed. They will be served by K, L and M buses on the surface, which will also serve Castro and Church Stations.
  • K Bus and M Bus will run between Church Station and Balboa Park Station.
  • L Bus will run between Church Station and the Zoo.
  • S Shuttle trains will run between Castro Station and Embarcadero Station.
  • Customers traveling further west will transfer to the K, L or M Bus at Church or Castro Station.
  • J Church and N Judah service will operate as usual. Customers traveling downtown can board the J and N trains at Church & Duboce or a Shuttle train at Church Station.
  • Next Muni predictions will be operating to provide arrival information to customers. Twin Peaks tunnel closure service plan map

Thank you for your support and understanding while we enhance and protect the tunnel's overall structure and stability. 

Contact Information
Jessie Liang