A worker prepares a concrete cylinder for installation underground. The cylinder is one component of a wall that will eventually be integrated into the Union Square/Market Street Station. During the next 10 days, construction to prepare for tunneling will continue in SoMa and Union Square. No Central Subway construction is planned in Chinatown or North [...]
This time lapse video — our first ever — shows the first steps of installing and assembling tunnel boring machine Mom Chung. For the past few weeks, Central Subway crews have worked day and night to install and assemble our first tunnel boring machine, Mom Chung, underground beneath 4th Street. We’ve documented the process on [...]
Crews continue to install subsurface pipes on 4th Street between Market and Stevenson. When the tunnel boring machines pass below, we will use to inject grout into the ground and improve soil conditions here. During the next 10 days, construction to prepare for tunneling will continue in SoMa and Union Square. No Central Subway construction [...]
San Francisco Mayor Edwin M. Lee takes a look at tunnel boring machine Mom Chung in the excavation under 4th Street where tunneling will begin. Yesterday, Mayor Edwin M. Lee paid a visit to the construction site where tunneling will begin and saw Mom Chung, the 350-foot-long tunnel boring machine currently being assembled underground. Speaking [...]
Crews are excavating a shaft on Ellis Street near where the Central Subway tunnels will pass beneath the existing BART and Muni tunnels. Crews will perform ground improvements here. During the next 10 days, construction to prepare for tunneling will continue in SoMa and Union Square. No Central Subway construction is planned to occur in [...]
On Ellis Street, crews continue to excavate and stabilize a shaft that will be used to perform ground improvements. During the next 10 days, construction to prepare for tunneling will continue in SoMa and Union Square, and we will perform a soil boring in North Beach. No Central Subway construction is planned to occur in [...]
Construction of underground walls is in progress on 4th Street between Howard and Folsom. During the next 10 days, construction to prepare for tunneling will continue in SoMa and Union Square. No Central Subway construction is planned to occur in Chinatown or North Beach. Descriptions of construction impacts in each neighborhood are available here or [...]
Beneath 4th Street, crews are pouring concrete to build the floor of the tunnel launch box between Harrison and Bryant. During the next 10 days, construction to prepare for tunneling will continue in SoMa and Union Square. No Central Subway construction is planned to occur in Chinatown or North Beach. Descriptions of construction impacts in [...]
On Ellis Street, crews are excavating this shaft to perform ground improvements. During the next 10 days, construction to prepare for tunneling will continue in SoMa and Union Square. No Central Subway construction is planned to occur in Chinatown or North Beach. Descriptions of construction impacts in each neighborhood are available here or at the [...]
At the site where tunneling will begin, crews have started to build a floor known as a mud slab on the bottom of the excavation. During the next 10 days, construction to prepare for tunneling will continue in SoMa and Union Square. No Central Subway construction is planned to occur in Chinatown or North Beach. [...]
