Construction Update
March 8 - 17, 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.
Northern SoMa (Market to Harrison): On 4th between Market and Stevenson and 4th Street between Folsom and Harrison, ground improvement work is now complete. We have begun to restore the roadway. At 4th and Folsom, work to prepare for the Yerba Buena/Moscone Station continues. This may include excavating a high-pressure water line at 4th and Folsom at night, as well as demolishing the roadway within the construction zone to prepare to construct underground station walls. This work will be noisy.
Union Square: Stockton Street between Ellis and Geary is closed to vehicular traffic to allow for construction of the Union Square/Market Street Station. Work is underway to construct shallow underground walls in preparation for the station construction.
Chinatown: The contractor will start 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. At 1731-1741 Powell, construction may be in progress on Saturdays from 7 a.m. to 5 p.m. Utility and roadway restoration on Columbus and Union.
We appreciate your patience and support while we build this essential upgrade to San Francisco's public transportation system.
-The Central Subway Team 
Exploratory utility work can be seen here on 4th Street, south of Brannan.
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.
- The bus stop located on Harrison and 4th streets will be relocated 150 feet west towards 5th Street.
Planned construction (Bryant to King):
- Potholing underway. Work will take place on 4th Street within construction zones marked by cones.
- Work may involve jackhammering 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.
- Perform soil sampling on 4th between Bryant and King
Traffic and pedestrian impacts (Bryant to King):
- 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
A sign marks the approach to the northbound tunnel S-curve, where the tunnel turns to move under the Market Street BART and Muni tunnels, then up Stockton Street. Northern SoMa
4th Street from Market to Harrison
On 4th Street between Market and Stevenson, construction is now complete. Crews will restore the roadway in the next few weeks.
On 4th Street between Howard and Folsom, preparatory work to construct the Yerba Buena/Moscone Station is now in progress at the corner of 4th and Folsom. Soil testing is underway and station construction will start soon.
On 4th Street between Folsom and Harrison, the contractor is restoring the area and will perform underground sewer surveys. We expect work at this location to be completed in March.
Planned construction (Market to Stevenson):
- Restore construction zone in a few weeks
Traffic and pedestrian impacts (Market to Stevenson):
- Two lanes of traffic will remain open on the west side of the street, with the work zone on the east side of the street (near Ross)
- The taxi stand has been relocated just south of Stevenson.
Planned construction (Howard to Folsom):
- Install test elements for underground walls
- Install shallow subsurface walls in preparation for station wall construction
- Investigate archeological conditions
- Planned work hours are Monday to Friday, 7 a.m. to 5 p.m.
- High-pressure water line replacement at 4th Street and Folsom, 7 p.m. to 5 a.m.
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 use the sidewalk on the east side of the street and cross at 4th and Howard.
- 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.
- Additional lane closures may occur in the evening at 4th Street and Folsom.
Planned construction (Folsom to Harrison):
- Restore construction zone
Traffic and pedestrian impacts (Folsom to Harrison):
- The parking lane and one lane of traffic on the eastern side of the street will be closed
- South of Clara Street, one additional lane may be closed to allow for work in the intersection of 4th and Harrison
Before constructing the underground station walls, crews first use these auger drills to excavate and remove abandoned basement walls and utilities.
Union Square
Stockton Street from Market to Post
On Stockton Street between Ellis and Geary, contractor Tutor Perini is building the Union Square/Market Street Station. Preparatory construction is now in progress, with the roadway closed to vehicle traffic.
Ground improvement related to tunneling is now complete on Ellis Street between Stockton and Powell streets. The contractor will be vacating the site in the next few weeks.
Planned construction (Stockton Street from Ellis to Maiden Lane):
- Demolish roadway and underground walls. This work, which involves breaking and removing the roadway pavement, will be noisy.
- Potholing for utilities
- Drilling and removal of sub-sidewalk basements
- Regular work hours are Monday-Friday, 7 a.m. to 5 p.m., with evening and weekend work required at times
Planned construction (Ellis Street):
- The tunnel contractor will vacate the area in a couple of weeks. The station contractor will then occupy the area.
Planned construction (Stockton Street from Sutter to Clay):
- No construction planned
Traffic, transit and pedestrian impacts:
- Stockton Street between Ellis and Geary is 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.
- The parking lane and one lane of traffic on the eastern side of the street will be closed between Post and Geary.
More information about construction at this site is available in this construction notice. 
At the Chinatown Station work site, this device, called a "hydromill" will eventually be used to help construct underground walls.
Chinatown
Stockton Street from Sacramento to Broadway
On Stockton Street from Sacramento to Broadway, construction of Chinatown Station is now underway within the property lines and nearby on Washington Street.
Planned construction:
- Construct station walls
- Night work: Fire hydrant installation on Washington near Trenton. Work hours are Monday-Friday, 5p.m. to 5a.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 Washington Street adjacent to Stockton Street may be closed during construction hours
At 1731-1741 Powell, crews are constructing a retrieval shaft to remove the two tunnel boring machines from the ground when tunneling is finished.
North Beach
Powell Street from Union to Columbus
On private property at 1731-1741 Powell Street, the contractor is building 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. We plan to complete work at this location in 2014.
On private property at 1455 Stockton Street, the contractor is constructing an underground shaft to perform ground improvements when the TBMs pass below Columbus Avenue.
On Columbus Avenue near the intersection with Union Street, crews will be completing underground sewer work and restore roadway, starting next week.
Planned construction (1731-1741 Powell):
- Excavate retrieval shaft and install bracing
- Construction hours are Monday to Saturday, 6 a.m. to 8 p.m.
- This Saturday, March. 8, construction will be in progress from 7 a.m. to 5 p.m.
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):
- Install ground improvement components within the shaft
- Work hours are Monday-Friday, 7 a.m. to 5 p.m.
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):
- Utility and roadway restoration in the next few weeks
- Construction hours on Columbus 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.