Construction Update
May 11-20, 2013
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 Beach.
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 May 20:
- Southern SoMa (Harrison to King/Berry): The on-ramp to westbound I-80 will remain open next week. Full closure of 4th Street between Harrison and Bryant will continue on some evenings and weekends. Two lanes of traffic will remain open on this block on at all other times. Please contact us at central.subway@sfmta.com if you have questions about the closure schedule. On Bryant Street at 5th Street, the left lane and several parking spaces will remain closed.
At these locations, current construction impacts are planned to continue until May 20:
- Northern SoMa (Market to Harrison): 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.
- 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
- North Beach: 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 
Under 4th Street, crews continue assembling tunnel boring machine Mom Chung. Tunneling is scheduled to begin in June. Southern SoMa
4th Street from Harrison to King/Berry
On 4th Street between Harrison and Bryant streets, the contractor has constructed a major excavation known as a launch box at the site where tunneling will begin. After assembly of a tunnel boring machine underground, tunneling will start this summer.
Planned construction:
- Install gantry crane inside launch box
- Assemble tunnel boring machine shield and trailing gear
- Deliver tunnel boring machine parts to Bryant Street staging area
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.
- The block may be closed to traffic from 8 p.m. to 4 a.m. on weeknights and all day Saturday and Sunday. When the Giants have home games, the closure will start an hour after the game ends.
- The sidewalk on the west side of the block will remain closed; the sidewalk on the east side of the block will remain open.
- On Bryant Street at 5th Street, the left lane and several parking spaces will be closed.
Traffic and pedestrian controls are in place. For more information on construction impacts at this site, check out this blog post. 
Crews continue to install subsurface pipes on 4th Street between Market and Stevenson. When the tunnel boring machines pass below, we will use the pipes to improve ground conditions here. 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 Market and Stevenson. More information is available in this construction notice.
Planned construction (Market to Stevenson):
- Install subsurface piping for ground improvements
- Perform ground improvements
- Remove abandoned gas line (tentative)
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):
- Construct 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 may 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
A member of the construction team descends into the shaft on Ellis Street where we will perform ground improvements. 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
- Construct floor slab in Ellis Street shaft
- Set up drill rig and drilling platform in Ellis Street shaft
- 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:
- No construction planned
Traffic, transit and pedestrian impacts:
- N/A
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.