The rail system, famous for slowing, perceptibly, at any hint of moisture in the air, got a software upgrade last year that made it resilient to wet weather. Now trains can keep rolling at 70 miles per hour without fear of the wheels skidding, no matter how slippery the tracks get.
"We realized we needed a solution," BART spokesperson Alicia Trost said, noting how the agency's rain protocol had affected its image and its on-time performance.
Before the fix, trains had to abruptly slow down whenever they reached an outdoor segment of track that had been exposed to storms, drizzle or even heavy mist. That meant dropping to 50 miles per hour in what would otherwise be a 70 mile per hour zone, or to 36 miles per hour in what would normally be a 50 mile per hour zone. The wettest months could see upwards of 7,000 train delays. Riders exchanged a tense joke that the damned fleet "must be made out of paper."
In 2024, a rather typical year for rainfall, inclement weather led to 34,356 delayed trains. That fall the board of directors approved a $4.3 million change order to BART's Fleet of the Future contract, allowing the manufacturer to incorporate "pre-braking actions" into the train software. As a result, trains could gradually decelerate between sections of track without fear of the wheels locking ("wheel flat" is the term of art). It's a bit like a driver braking delicately between stretches of freeway with different speed limits, said Leonardo Pica, BART's assistant chief mechanical officer.
Engineers began implementing the technology last year, finishing in April. Since the software triggers gentle reductions in speed, it's added a barely discernable amount of time to each trip, Pica said. The end-to-end journey from Richmond to Millbrae, for example, is about two minutes longer, regardless of the weather. Flat wheels occasionally still happen, Pica said, and will likely continue to plague BART until the agency finishes its years-long train control modernization project.
But, so far, the rainy day numbers are promising. From July through December of 2024, 48 "rain incidents" led to 11,903 delayed trains. During that same period the following year, agency staff documented 22 downpours and 128 delays. January showers caused 62 trains to slow down, and BART logged 96 weather delays so far this month.
When a Pineapple Express lashes the Bay Area on Tuesday morning, Pica expects BART trains to keep coasting. If all goes according to plan, passengers will clatter toward MacArthur Station at 50 miles per hour, gazing through rain-smeared windows at the traffic snarled on Interstate 580.
At least some riders say they have noticed a change.
"I haven't heard all those service announcements saying, 'BART is running slow because of rain,'" said Stefan Aronsen, who was pushing an electric bike along the platform at Powell Street station Monday morning. Aronsen used to regularly arrive late to work on rainy days, commuting from Oakland to downtown San Francisco. He said the BART trip took several minutes longer than normal, as trains "crept" along the exposed track between MacArthur and 19th Street stations, or from 12th Street through West Oakland to the Transbay Tube.
Transit riders though, are a stoic bunch. A few said they weren't particularly bothered if BART slowed to spare its equipment during a bomb cyclone.
"I definitely noticed it in the past," said Payoja Adhikari, an Oakland resident who was waiting for a train at El Cerrito Del Norte station. She takes BART to social engagements or to run errands, and said she's usually not in a hurry. "If I had to use it for work, I think I'd be more concerned," she said.
Other people admitted they are too absorbed with their phones or reading material to take heed of the train's velocity. A couple remembered feeling mild irritation, saying a late BART train only exacerbates a miserably soggy day.
What many saw as a seasonal nuisance became a real quandary for BART managers, who feared the disruptions were driving away passengers. BART, like other transit agencies, has struggled to regain ridership in the wake of the pandemic and the rise of remote work. Now faced with a deficit that could grow to $400 million a year, officials at BART are pursuing every possible improvement to lure people back.
At the same time, supporters of public transportation are pushing a sales tax for the November ballot to shore up BART, Muni, Caltrain and AC Transit. It can only succeed if voters see these agencies as worthy of a bailout.
Running reliably in a rainstorm is a good place to start.
©2026 the San Francisco Chronicle, Distributed by Tribune Content Agency, LLC.
