Heads up, those who ride Muni’s K, L, M, and S lines — the West Portal and Forest Hill stations, and all of the Twin Peaks Tunnel, will be closed for eight whole days, effective Thursday morning.

The Muni light-rail’s Twin Peaks Tunnel connecting the Castro, West Portal, and Forest Hill stations is more than 100 years old, and it needs a little maintenance from time to time. The tunnel was shut down for repairs the weekend of June 22-23 (the weekend before this year’s SF Pride), and a month later was closed for the weekend of July 20-21. But the tunnel’s biggest closure now looms starting Thursday morning, as NBC Bay Area reports the SFMTA will close the Twin Peaks Tunnel for eight days, for the entirety of Thursday, August 22 through Thursday, August 29.

The West Portal and Forest Hill stations will be closed for the entire eight days. Westbound light-rail trains will stop at Church Street station, and there will be bus service for the K-Ingleside, L-Taraval, and M-Ocean View lines onward from there.

“The Twin Peaks Tunnel has over a century of service under its belt and needs work to keep up with the demands of time and the Muni system,” SFMTA says in a release. “The SFMTA conducts regular inspections and structural evaluations of the tunnel, and expects to make additional improvements to the tunnel over the next 5-10 years to keep it safe and reliable for years to come. We are doing everything we can to keep the shutdown durations short and will work closely with riders, merchants, and residents to minimize any disruptions.”

The above diagram breaks down where you would have to catch a bus if you’re a K, L, or M rider. The L-Taraval will be bus-only between the Church Street station and the SF Zoo, which is already a familiar arrangement for those riders. The K-Ingleside and M-Ocean View will be bus-only from Church Street to the Balboa Park station, though following their normal respective routes.    

The S-Shuttle will have curtailed service, running only between the Embarcadero and Castro Street stations for the eight-day span. The J-Church, N-Judah, and T-Third lines will not be affected.

The Twin Peaks Tunnel is scheduled to reopen, with all trains running normally, in the early morning of Friday, August 30, as we barrel into Labor Day Weekend.

Related: Twin Peaks Tunnel Closes This Weekend for Repairs, Muni Trains Stopping at Castro [SFist]

Image via SFMTA