The SFMTA is undertaking another week (or so) of maintenance on the Muni Metro later this month, and this will mean no underground service for commuters leaving the office late or anyone trying to get home after dinner by train.

The routine maintenance project will kick off on January 26, and it will affect all trains that run between Embarcadero and West Portal Station. The work will address overhead lines, signals, tracks, and the computerized train control system that runs the trains when they enter the tunnels. During the hours of 9:30 p.m. to 1 a.m., bus shuttle service will replace the trains up and down the Market Street corridor and out to above-ground trains at Church and Duboce and at West Portal. The T line will run only between Sunnydale and Embarcadero & Brannan.

"The SFMTA maintenance crews work hard every night after Muni Metro subway service hours to maintain the tracks and equipment underground," Muni explains. "On most nights, this gives them only about two hours to get work done. In order to complete critical maintenance tasks that cannot be completed during normal windows, we are planning a week of early subway closures, so crews have more hours each night to do this vital work." The last time closures like this occurred was in August.

SFMTA spokesperson Erica Kato tells Hoodline that the scope of work will be similar to the one in August, and "We’re allowing staff [time] to conduct routine and more detailed maintenance to keep operations in a state of good repair."

Muni shuttle stops along Market Street will be designated with half-moon-shaped yellow "Shuttle" signs. And as Muni explains, "Inbound N Judah and outbound J Church trains will use the accessible stop entering the Duboce Portal to serve customers needing the ramp."

Related: Fresh Flaws Found in New Muni Train Cars as It Turns Out They Rear-End Each Other