by lpetrich
Welcome to SFMTA Central Subway | SFMTA Central Subway
Preliminary construction has started, mainly utility relocation and preparation for tunneling. Full-scale construction will start next year.
Tunnel Construction | SFMTA Central Subway That page has an nice computer-graphics video of a tunnel-boring machine in action. It's heavily automated, complete with automated installation of tunnel lining. This approach will be used instead of cut-and-cover, because it causes much less surface disruption.
The route starts at the surface at 4th & King Sts., near the Caltrain station, and goes north in 4th St. After a station at 4th & Brannan, it goes underground at I-80, having a station at Yerba Buena / Moscone Center. It crosses Market St. to a station at Union Square / Market St., and continues northward in Stockton St. Its last station is at Chinatown, between Clay St. and Washington St. The tunnel continues further to Columbus Ave. and Union St., near Washington Square Park, where it ends. A possible future North Beach station?
The TBM will be a necessity for avoiding climbing the hill at the northern part of the route. Stockton St. has a tunnel from just south of Bush St. to between California and Sacramento Sts. Union Sq. / Market St. shows the depth of that station's tracks -- about 5 stories below street level. That will be enough to go beneath the Market St. BART/Muni-Metro tunnel.
Preliminary construction has started, mainly utility relocation and preparation for tunneling. Full-scale construction will start next year.
Tunnel Construction | SFMTA Central Subway That page has an nice computer-graphics video of a tunnel-boring machine in action. It's heavily automated, complete with automated installation of tunnel lining. This approach will be used instead of cut-and-cover, because it causes much less surface disruption.
The route starts at the surface at 4th & King Sts., near the Caltrain station, and goes north in 4th St. After a station at 4th & Brannan, it goes underground at I-80, having a station at Yerba Buena / Moscone Center. It crosses Market St. to a station at Union Square / Market St., and continues northward in Stockton St. Its last station is at Chinatown, between Clay St. and Washington St. The tunnel continues further to Columbus Ave. and Union St., near Washington Square Park, where it ends. A possible future North Beach station?
The TBM will be a necessity for avoiding climbing the hill at the northern part of the route. Stockton St. has a tunnel from just south of Bush St. to between California and Sacramento Sts. Union Sq. / Market St. shows the depth of that station's tracks -- about 5 stories below street level. That will be enough to go beneath the Market St. BART/Muni-Metro tunnel.