Construction Update
April 20-29, 2013
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 Chinatown.
For descriptions of construction impacts in each neighborhood, scroll down or click on the links below. We also post construction, traffic detour and Muni impact information on our project Google Map.
Construction impacts are planned to change at these locations by April 29:
- Southern SoMa (Harrison to King/Berry): Starting Monday, April 20, full closure of 4th Street between Harrison and Bryant will be in effect some evenings and weekends while we install a gantry crane and lower a tunnel boring machine into the tunnel launch box. Two lanes of traffic will remain open on this block at all other times. Please contact us at central.subway@sfmta.com if you have questions about the closure schedule.
- Northern SoMa (Market to Harrison): On 4th Street between Folsom and Harrison, all lanes are planned to reopen to traffic on Friday, April 26. On 4th Street between Market and Stevenson, the sidewalk and two traffic lanes will remain closed on the eastern side of the street. Two lanes of traffic will remain closed on 4th Street between Howard and Folsom.
- North Beach: To facilitate a soil boring, the parking lane on Powell Street between Union and Columbus may be closed during construction hours (7 a.m. to 7 p.m.) from Monday, April 22, until Wednesday, April 24.
At these locations, current construction impacts are planned to continue until April 29:
- Union Square: Stockton Street between Geary and Ellis will remain closed to vehicle traffic. Ellis Street between Stockton and Powell will remain closed to westbound traffic.
- Chinatown: No construction planned
We appreciate your patience and support while we build this essential upgrade to San Francisco's public transportation system.
-The Central Subway Team
Crews are working on the final components of the tunnel launch box in preparation for installation of the tunnel boring machine. Southern SoMa
4th Street from Harrison to King/Berry
On 4th Street between Harrison and Bryant streets, the contractor is constructing a major excavation known as a launch box at the site where tunneling will begin.
Planned construction:
- Construct launch seal for southbound tunnel
- Construct access ramp floor slab
- Install gantry crane
- Assemble tunnel boring machine shield
Traffic and pedestrian impacts:
- The two lanes on the east side of the street (left lanes for southbound traffic) will remain open to vehicle traffic except as described below
- Starting Monday, April 20, the block may be closed to traffic at night from 8 p.m. until 4 a.m. to facilitate installation of a gantry crane and a tunnel boring machine. On evenings when the Giants have home games, the closure will start an hour after the game ends.
- Next weekend, April 27-28, this block may be closed to facilitate installation of a tunnel boring machine
- The on-ramp to westbound I-80 may be closed from 8 p.m. to 4 a.m. on weeknights and all day Saturday and Sunday
- The sidewalk on the west side of the block will remain closed; the sidewalk on the east side of the block will remain open
Traffic and pedestrian controls are in place. For more information on construction impacts at this site, check out this blog post. 
Ground improvements will be underway at this site on 4th Street just south of Market Street. Northern SoMa
4th Street from Market to Harrison
On 4th Street between Howard and Folsom streets, the contractor is constructing below-ground walls, called headwalls, at the site of the future Yerba Buena/Moscone Station. The walls will cross 4th Street at two points on this block. For more information on construction at this site, check out this blog post.
In addition, the contractor is performing ground improvement work (installation of compensation grout tubes) on 4th Street between Folsom and Harrison. More information is available in this construction notice.
Ground improvement work on 4th Street between Market and Stevenson is also underway. For more information on upcoming construction at this site, check out this construction notice.
Planned construction (Market to Stevenson):
- Investigate underground utilities
Traffic and pedestrian impacts (Market to Stevenson):
- Two lanes on the eastern side of the street (near Ross) will be closed
- The sidewalk on the eastern side of the street may be closed. A protected pedestrian walkway will be in place around the construction zone.
Planned construction (Howard to Folsom):
- Construction of new water line
- Construction of subsurface walls (headwalls)
Traffic and pedestrian impacts (Howard to Folsom):
- At least two lanes of traffic on 4th Street will remain open on the western side of the block except as described below
- One night next week, traffic will be reduced to one lane from 8 p.m. to 6 a.m. to allow for the installation of a rebar cage
- The sidewalks will not be impacted
Planned construction (Folsom to Harrison):
- Install subsurface piping for ground improvements
- Perform ground improvements
- Commence temporary restoration of roadway
Traffic and pedestrian impacts (Folsom to Harrison):
- One lane on the eastern side of the street (near Pacific Bicycle and Whole Foods) will be closed until Friday, April 26
- Starting Friday, April 26, all lanes are planned to reopen to traffic
- The crosswalk crossing 4th Street at Clara Street may be temporarily closed when construction is in progress
The round rebar cylinders shown here will reinforce an underground wall at the future site of the Union Square/Market Street Station. Union Square
Stockton Street from Market to Post
On Stockton Street between Geary and Ellis streets, the contractor is installing below-ground walls called headwalls at the site of the future Union Square/Market Street Station. In addition, ground improvement is underway on Ellis Street between Stockton and Powell streets.
Planned construction:
- Install headwalls on Stockton Street between Ellis and O'Farrell
- Excavate ground improvement shaft on Ellis Street
- Perform ground improvements on Stockton Street between O'Farrell and Geary
- The contractor will continue working two shifts on weekdays, from 6 a.m. to 12:30 a.m.
- On Saturdays, work hours will be 6 a.m. to 10 p.m.
Traffic, transit and pedestrian impacts:
- Stockton Street between Geary and Ellis is closed to all vehicles except emergency vehicles
- Ellis Street between Stockton and the Ellis-O'Farrell Garage (between Stockton and Powell) is closed to westbound traffic
- The 38/38L Geary may experience delays around Union Square
- Sidewalks on Stockton Street between Ellis and Geary will remain open, but they may be narrowed to facilitate construction
More information about construction at this site is available in this construction notice and this press release. 
This property on Washington Street is the future location of the Chinatown Station. Chinatown
Stockton Street from Sacramento to Broadway
No construction is planned to occur in Chinatown during the next 10 days. 
The Central Subway tunnel will end at this site in North Beach, now home to the old Pagoda Palace theater. North Beach
Columbus Avenue from Union to Filbert
On private property at 1731-1741 Powell Street, the contractor is preparing to construct a walled excavation known as a retrieval shaft at the site where tunneling will end. The two tunnel boring machines will be removed from the ground at this location.
Planned construction:
- Perform soil boring on Powell Street
- Work hours are from 7 a.m. to 7 p.m.
- Work is planned to commence Monday, April 22, and may continue until Wednesday, April 24
Traffic, transit and pedestrian impacts:
- The parking lane on Powell Street between Union Street and Columbus Avenue may be closed during construction hours
More information is available in this construction notice.
Central Subway Construction Fast Facts
Project Alignment: 4th Street between Berry and Market streets; Stockton Street between Market Street and Columbus Avenue; Columbus Avenue between Stockton and Filbert streets.
Transit Reroutes: The southbound 8X/8AX/8BX Bayshore Express, 30 Stockton, 45 Union/Stockton and 91 Owl Muni bus routes have been rerouted to accommodate construction in Union Square and SoMa. These reroutes will remain in effect throughout the duration of Central Subway construction. More information is available online here.
Contact Us: Should you have questions about construction or the Central Subway Project, don't hesitate to contact our team. You can reach us at central.subway@sfmta.com or by phone at 415-701-4371.
For More Information: The Central Subway team posts frequent project updates on a variety of social media outlets. To find out more about the project and construction progress, follow us on Facebook, Twitter, Instagram or Flickr, and check out our blog.
Construction schedules are subject to change.