BART was forced to close all 50 stations in the system Friday morning around 4:30 am due to an issue that was affecting service in the entire system.

The BART agency put out an alert at 4:29 am Friday saying that a problem with the computerized train control system. Commuters were told at that time to find "alternative modes of transportation," and as the New York Times reports, traffic on and heading to the Bay Bridge was thick as of 7 am.

BART Chief Communications Officer Alicia Trost was up early Friday taking questions from local news stations like ABC 7.

"What's the issue is our train control computer cannot turn on properly, so that the staff in the control center can see everything, and that's obviously not safe," Trost said. "So we're not going to run service until all those things happen." Trost added that all of the system's servers needed to be reset.

The last time all BART service came to a screeching halt was on a Friday in January 2023, at a time when fewer people were going back to work in the third year of the pandemic, especially on a Friday. That disruption was caused by an unexpected track maintenance issue.

And as ABC 7 notes, the last time the entire train control system went down in 2019, it took several hours to come back online. As of this writing, the system remains down after more than four hours.

Update: As of 9 am, BART began returning trains to service in the East Bay only. It was not clear when full service would resume.

Update 2: All stations in the system were back open and service was resuming in San Francisco and in San Mateo County as of 9:20 am, about five hours after the problem began.

BART seemed somewhat relieved that this happened on a relatively low-ridership day. As spokesperson Alicia Trost told the Chronicle, "It’s never a good day, but ridership is significantly less on Friday."

Photo by Charles Forerunner