As we've reported, a big construction project is headed to Twin Peaks Tunnel, which connects Castro and West Portal stations on the K, L, and M light-rail lines. According to the SFMTA's latest update, construction will kick off in the fall, but construction staging areas have already been established in West Portal, and are headed to the Castro this month.
Per the SFMTA:
Our contractors, NTK Construction, are steadily gearing up for construction inside Twin Peaks Tunnel. Though construction is not scheduled to start until the fall, crews have established a staging area on the west (West Portal) side of the tunnel to store materials and equipment for quick access while they work. Another staging area on the east (Castro) side of the tunnel is expected to be established in August. The staging area on the west side of the tunnel is along Junipero Serra Boulevard between Ocean Avenue and Sloat Avenue. The staging area on the east side of the tunnel is along Market Street between Collingwood Street and Castro Street.
These areas are vital for storing construction materials and equipment needed to complete the track replacement and help avoid production delays. Through August, crews may begin prep work, such as welding or installing protective fencing, in these staging areas to prepare for the construction in the fall.
Once construction kicks off, the tunnel will be closed on intermittent weekends through the fall of 2017, with above-ground shuttle buses running instead.