With 100 years of service under its belt, Twin Peaks Tunnel needs extensive work to its interior to continue to operate safety and reliably for years to come. The tunnel's infrastructure, including the tracks, walls and drainage systems, must be maintained in a timely manner to keep up with the demands of the Muni system. Twin Peaks Tunnel is currently under a speed restriction, which slows down trains as they travel through. Replacing the tracks will lift the tunnel's speed restriction and keep trains running reliably through the system. Seismic reinforcements will better protect the tunnel's overall structure and stability.
Construction is expected to start June 25 during a continuous closure of the tunnel for two months. During the closure, Forest Hill and West Portal stations will be closed, the K Ingleside will travel on a shortened route, and bus service will run for the L Taraval and M Ocean View lines. Nx buses will not operate during the closure, but additional N Judah trains will be in service. More details about getting around are below.