The T-Third metro rail line, which runs from Chinatown through Bayview-Hunters Point and ends at the border with Daly City, will be out of commission for the next two weekends. A bus bridge will shuttle commuters between stops instead.
The city is upgrading the line, fixing lighting, signage, and wiring.
The fixes, which are the first of their kind since the line was installed in 2007, are “long overdue,” said Supervisor Shamann Walton.
“People in the community have been asking for this for years,” said Walton. “We’re glad the work is happening.”
The pause only affects the older portions of the line in the southeastern part of the city, not those going up to Chinatown. Service on the T-Third will be cut from Third and Marin streets to Sunnydale on July 18 and 19, and from Third and Williams streets to Sunnydale on July 25 and 26.
Residents can still expect to get to where they need to go. An articulated, 60-foot bus will replace the T-Third on both weekends, stop at the same stations, and run with the same frequency, a spokesperson for the San Francisco Municipal Transportation Agency said.
The T-Third’s extension into Chinatown with the opening of the Central Subway is no more than three years old. But in the southeast of the city, the rest of the T-Third is starting to show signs of age.
“That’s where we noticed we needed to do the most work,” said Madhu Unnikrishnan, a spokesperson for the SFMTA, and a Bayview resident. “The infrastructure is aging,” said Unnikrishnan, who often notices missing tiles at his usual bus stop on Third Street.
“We have to fix overhead wires, clean the tracks … repair broken glass, painting, general cleaning and housekeeping.” In addition to lighting and signage fixes, the agency will clean the line’s tracks, grooves, and overhead lines.
Commuters have long complained about the T-Third’s slow service and frequent delays.
The improvements follow a multi-year project to improve the reliability of the T-Third launched in August 2025 by the SFMTA. It is starting to bear fruit.
The SFMTA was recently able to decrease the line’s travel time by approximately seven minutes by modernizing and adjusting San Francisco’s transit signal priority technology, the agency said.
The technology communicates with standard traffic lights to prioritize light-rail vehicles, leaving a traffic light green for longer if the technology senses a light-rail vehicle is approaching.
During the four days of its shutdown, SFMTA crews will also make sure that new technology is working properly.
“We’re committed to ensuring that the T-Third is in a state of good repair and continues to serve the community,” said Unnikrishnan. “We’re doing this in the least disruptive way we can.”
“The technology communicates with standard traffic lights ”
Which begs the question how many traffic lights are out there which are not standard, and how come we have (proprietary San Francisco only?) non-standard traffic lights.
Supervisor Walton is correct about the community waiting a long time for this. This investment will be welcome. For example, systems running under the Islais Creek drawbridge need to be overhauled. Nonetheless, light rail service has been much better than the first several years when it seemed slower than the #15 bus that it replaced.