Construction Update
May 24 - June 2, 2014
During the next 10 days, Central Subway work will continue at sites in SoMa, Union Square, Chinatown and North Beach. This section contains brief updates about what is happening in each neighborhood. For more detailed information, scroll down or click on the links below. We also post construction, traffic detour and Muni impact information on our project Google Map.
Southern SoMa (Harrison to King/Berry): Potholing for utilities will continue next week on 4th Street between Bryant and King. A temporary walkway is in place around the construction zone. At the tunnel launch box on 4th Street between Harrison and Bryant, tunneling continues with both TBMs. Three lanes of the I-80 off-ramp at 4th and Bryant may be closed weeknights from 12 a.m. to 5 a.m. One lane of the I-80 off-ramp at 4th and Bryant may be closed during the daytime from 10 a.m. to 3 p.m.
Northern SoMa (Market to Harrison): At 4th and Folsom, work to prepare for the Yerba Buena/Moscone Station continues. This will include construction of the station walls within the work site and water line replacement at the intersection Fourth and Folsom. Night work is planned for these activities.
Union Square: Stockton Street between Ellis and Geary is closed to vehicular traffic and partial closure to vehicular traffic between Geary to Post to allow for construction of the Union Square/Market Street Station. Work is underway to excavate material before constructing station walls. Construction hours will be Monday to Saturday from 7 a.m. to 11 p.m. Starting Tuesday, May 28, one traffic lane will be closed on Geary between Stockton and Powell from 8 p.m. to 4 a.m. This closure will be on weeknights until June 30.
Chinatown: The contractor has started station wall construction within the future station site and on the adjacent section of Washington Street.
North Beach: Work will continue at 1455 Stockton and 1731-1741 Powell. Sewer, roadway and sidewalk restoration on Columbus and Union will continue and is expected to be completed by the 3nd quarter of 2014.
We appreciate your patience and support while we build this essential upgrade to San Francisco's public transportation system.
-The Central Subway Team 
Temporary barriers help pedestrians safely navigate around this work site just south of Bryant, on 4th.
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 the Central Subway tunnels begin. After assembly of two tunnel boring machines (TBM) underground, tunneling is underway, with operations based here.
On 4th Street between Bryant and King streets, potholing for utilities is now underway. Potholing involves drilling small holes and trenches in the street to confirm the locations of existing utility lines. More information is available in this construction notice.
Planned construction (Harrison to Bryant):
- Construct tunnel for southbound trains (TBM Mom Chung)
- Construct tunnel for northbound trains (TBM Big Alma)
Traffic and pedestrian impacts (Harrison to Bryant):
- 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 close to traffic from 8 p.m. to 5:30 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.
- On Bryant Street at 5th Street, the left lane and several parking spaces will be closed.
Planned construction (Bryant to King):
- Potholing underway. Work will take place on 4th Street within construction zones marked by cones.
- Work may involve jack-hammering and cutting holes in the road. Please expect an increase in noise.
- Work hours will be Monday to Friday, 7 a.m. to 5 p.m.
- Continue installation of AT&T duct bank on the east side of 4th Street between Welsh and Bluxome.
Traffic and pedestrian impacts (Bryant to King):
- Three lanes of the I-80 off-ramp at 4th and Bryant may be closed weeknights from 12 a.m. to 5 a.m.
- One lane of the I-80 off-ramp at 4th and Bryant may be closed weekdays from 10 a.m. to 3 p.m.
- Temporary partial lane closures will be in effect on 4th Street in the vicinity of the construction zone.
- Parking will be impacted in the vicinity of the construction zone. The contractor will post 72-hour notification as required.
- Sidewalks may be impacted. The contractor will maintain a safe path of travel at all times.
- The contractor will maintain access to all businesses during business hours.
This crane being assembled will be used to help excavate and build underground walls which will become the outer structure of the new station. Northern SoMa
4th Street from Market to Harrison
On 4th Street between Howard and Folsom, work to construct the Yerba Buena/Moscone Station is now in progress. Work is underway to construct underground station walls.
Planned construction (Howard to Folsom):
- Install artwork on barricades along Folsom Street at back of sidewalk.
- Begin underground station wall construction.
- Begin replacing water line at intersection of Folsom and Fourth.
Traffic and pedestrian impacts (Howard to Folsom):
- The two right lanes of 4th Street will remain closed to traffic.
- Clementina between 4th and 5th is closed to thru traffic. Please use this block for local access only.
- The sidewalk on the west side of 4th Street between Clementina and Folsom will be closed. To ensure pedestrian safety, please cross at 4th and Howard and use the sidewalk on the east side of 4th street to access Folsom.
- Big trucks will enter and exit the 4th and Folsom site during work hours. Flaggers will be on site to facilitate truck entry and exit.
- Lanes closures will be in place along Folsom Street for the water line replacement work.
These steel I-beams (photo right) are used to reinforce piles which will become part of the station's exterior walls. Some I-beams are over 130 feet long.
Union Square
Stockton Street from Ellis to Post
On Stockton Street between Ellis and Post, contractor Tutor Perini is building the Union Square/Market Street Station. Preparatory construction is now in progress, with the roadway closed to vehicular traffic.
On Ellis Street between Stockton and Powell streets, crews will begin to pothole for utilities.
Planned construction (Stockton Street from Ellis to Post):
- Demolish roadway and underground walls. This work, which involves breaking and removing the roadway pavement, will be noisy.
- Potholing for utilities at Stockton and O’Farrell, and Stockton and Geary will occur in the evening.
- Installing guide walls for pile installation.
- Construction hours will be Monday to Saturday, 7 a.m. to 11 p.m., with weekend and evening work required at times. Starting on Friday May 30, work at the intersection of Geary and Stockton may be 24 hours. This work is expected to take six weeks.
- Continue pile installation to construct station walls.
- Begin obstruction removal and pile installation on the west side of Stockton between Geary and Maiden Lane.
Planned construction (Ellis Street):
- Potholing for utilities.
Traffic, transit and pedestrian impacts:
- Stockton Street between Ellis and Geary is closed to vehicular traffic.
- Stockton Street between Post and Geary is partially closed to vehicular traffic.
- Sidewalks will remain open, but they will be narrowed.
- Ellis Street between Stockton and the Ellis-O'Farrell Garage (between Stockton and Powell) will remain closed to westbound traffic.
- On Geary between Stockton and Powell, one traffic lane will be closed from 8 p.m. to 4 a.m.
- The bus stop on Geary and Stockton will be temporarily closed. Please board buses at Geary and Powell or Geary and Kearny.
More information about construction at this site is available in this construction notice. 
A worker inspects the rotating cutter wheels on the hydromill, a machine used to excavate soil before building underground station walls.
Chinatown
Stockton Street from Sacramento to Jackson
On Stockton Street from Sacramento to Jackson, construction of Chinatown Station is now underway within the property lines and nearby on Washington Street.
Planned construction:
- Construct station walls.
- Construction hours are Monday to Saturday, 7 a.m. to 11 p.m.
- Rebar delivery will be made between the hours of 4 a.m. to 6 a.m.
- Replace high pressure water pipeline and install new fire hydrant on Washington between Stockton and Spofford.
- NIGHT WORK: Concrete will be poured for the slurry wall. Work will end before 12 a.m.
Traffic, transit and pedestrian impacts:
- Washington Street between Stockton and Trenton will remain closed to vehicles and pedestrians.
- Washington Street between Powell and the construction zone has been converted into a two-way street.
- To ensure safety, please obey all traffic and pedestrian signs in the area.
- The parking lanes along Clay Street adjacent to Stockton Street may be closed during construction hours.
- Both parking lanes along Washington Street between Spofford and Stockton will be closed while fire hydrant work is being conducted.
Engineers are allowing the TBM retrieval shaft to slowly fill with groundwater. The water will help the TBMs maintain pressure on their cutterheads during breakthrough.
North Beach
Powell Street from Union to Columbus
On private property at 1731-1741 Powell Street, the contractor has built 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 here. The contractor is on schedule to complete the major work at this site in the 4th quarter of 2014. With minor restoration activities to follow, the site will be vacated early January 2015.
On private property at 1455 Stockton Street, the contractor will be restoring the site.
The contractor has started replacement of a water line along Columbus Avenue between Union Street and Filbert Streets. Final sidewalk and street restoration will follow and is expected to be complete by the 3rd Quarter of 2014.
Planned construction (1731-1741 Powell):
- Construction hours are Monday to Friday, 6 a.m. to 7 p.m. with weekend and evening work required at times. During the breakthrough of the southbound tunnel's TBM, crews will be on site 24 hours in anticipation to inject compensation grouting.
- At 6 a.m. on Thursday, May 29, the contractor will be pouring concrete.
Traffic, transit and pedestrian impacts (1731-1741 Powell):
- Several parking spaces may be closed in front of the property.
- The sidewalk in front of the property may be closed. A temporary walkway will be in place around the construction zone when the sidewalk is closed.
Planned construction (1455 Stockton):
- Site restoration will be in progress.
Traffic, transit and pedestrian impacts (1455 Stockton):
- No impacts to traffic, transit or pedestrian walkways are anticipated.
- The parking lot at 1455 Stockton will remain closed.
Planned construction (Columbus and Union):
- Potholing, water pipe replacement, roadway and sidewalk restoration.
- Construction hours are Monday to Friday, 9a.m. to 3p.m.
Traffic, transit and pedestrian impacts (Columbus and Union):
- On Columbus between Union and Filbert, the left lane for northbound traffic will be closed during construction hours.
- The northbound bus stop on Columbus at Union will remain open, but it will be temporarily relocated about 100 feet to the north during construction hours
Central Subway Construction Fast Facts
Project Alignment: 4th Street between Berry and Market streets; Stockton Street between Market Street and Columbus Avenue; Powell Street between Union Street and Columbus Avenue; Columbus Avenue between Powell 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.