Muni rail service will be temporarily suspended due to a positive COVID-19 coronavirus test and technical issues in the agency's subway tunnels. (Photo by Josh Wilburne/Unsplash)

Muni rail service is shutting down in San Francisco again for the next several weeks starting Tuesday, three days after it resumed following five months of being suspended due to the COVID-19 pandemic.

The Muni Metro system had resumed Saturday but is shutting down for the foreseeable future after two splices in the subway overhead wire failed and someone in the system’s control center tested positive for COVID-19.

Starting Tuesday, all rail service will be provided by bus. More details about how the closures are affecting various lines can be found at https://www.sfmta.com/travel-updates/bus-substitution-all-rail-lines.

Jeffrey Tumlin, director of transportation for the San Francisco Municipal Transportation Agency, wrote on Twitter about the problems and apologized to Muni riders who will be affected.

Tumlin said contact tracing protocols mean other controllers in Muni’s Transportation Management Center will be in quarantine.

“Our rail system has small teams of amazing technical experts. The system doesn’t work if a few of them are out,” he wrote. “It was fear of this scenario that caused us to shut system in April.”

Tumlin said agency officials will be working through the night to rebuild Muni’s bus schedule for the third time since April, with delays expected Tuesday morning.

“While today’s troubles expose the vulnerabilities of our rail system, they also show the phenomenal resiliency of our buses, and confirm the hard choices we made back in April. COVID is forcing all systems to be more resilient and adaptable,” he wrote.

Dan McMenamin is the managing editor at Bay City News, directing daily news coverage of the 12-county greater Bay Area. He has worked for BCN since 2008 and has been managing editor since 2014 after previously serving as BCN’s San Francisco bureau reporter. A UC Davis graduate, he came to BCN after working for a newspaper and nonprofit in the Davis area. He handles staffing, including coaching of our interns, day-to-day coverage decisions and management of the newswire.