Here's the most recent Bay City News summary of the incident:

The incident started around 8:20 a.m. when a parking brake deployed in error on a train bound for San Francisco International Airport on the Pittsburg-Bay Point line, according to BART spokesman Jim Allison.

The train became disabled, blocking the tracks, and a "brake dust" filled some of the cars, BART spokeswoman Luna Salaver said.

"There was absolutely no fire on the train," Salaver said.

There were 600 to 700 passengers on the train at the time, and they were in the Berkeley Hills tunnel until the mechanical issues were resolved and the train began moving again about an hour later, Allison said.

Update, 11 a.m.: BART now says that service is resuming through the Berkeley Hills Tunnel after a closure of more than two hours. The transit agency says passengers should expect delays of 15 minutes or so as service on the line from Bay Point to San Francisco International Airport gets back to normal.

BART says the apparent smoke in the incident was not smoke at all, but brake dust. The dust was apparently emitted after a parking brake malfunctioned and deployed while the affected train was headed west through the Berkeley Hills Tunnel.

Update, 10:45 a.m.: Rick Hurd and Harry Harris with the Bay Area News Group report at least five train passengers have been hospitalized after this morning's BART incident:

Several BART passengers reported a stressful wait and poor communications after the train, which was running on the Pittsburg-Bay Point line, stalled around 8:30 a.m. A parking brake had deployed and kept it from moving while it was in the Berkeley Hills tunnel between the two stations, according to BART spokesman Jim Allison.

Woman being treated with oxygen at Rockridge BART station. (Jane Tyska)
"Everybody was trying to stay calm," said Kaylee Adams of Walnut Creek, who was on her way to work in San Francisco. "We were trying to help each other out. It was scary. I was in the first car, and it was really stinky."

A BART technician was able to correct the problem, and the train eventually was moved on its own power into the Rockridge Station, where waiting passengers already had been evacuated from the platform, Allison said. The train's passengers were evacuated at 9:34 a.m.

Update, 10 a.m.: BART has reopened the Orinda and Rockridge stations for what the district describes as "very limited" service. From Orinda, that means trains are only running on the Pittsburg-Bay Point line east of the tunnel, with no service to San Francisco. From Rockridge, no service is yet available through the Berkeley Hills Tunnel to Contra Costa County.

Update, 9:50 a.m.: KTVU and other sources report that paramedics are treating at least 10 passengers from the disabled train for smoke inhalation, and more are being triaged.

Update, 9:40 a.m.: BART's reporting major delays on its Pittsburg-Bay Point line due to a crowded San Francisco-bound train that was halted in the Berkeley Hills Tunnel because of smoking brakes.

BART crews managed to move the train out of the tunnel to Oakland's Rockridge station just after 9:30 a.m. Firefighters and paramedics were awaiting the train amid reports that some passengers had complained about smoke inhalation.

The source of the smoke was unknown, but reports from various sources say it came from brakes on one of the train's cars.

This morning's incident is the latest in a string of mishaps for the transit system, including a partial shutdown of the Transbay Tube last week because of debris on a track. On Nov. 22, all service was shut down during the early morning commute because of a systemwide computer malfunction. And in late October, an eastbound Pittsburg/Bay Point train caught fire at the Orinda station, forcing a commute-hour evacuation and slowing service for hours.

Those incidents, along with a continuing contract dispute between the agency and its unions that triggered two strikes earlier this year, has prompted widespread criticism of the system among riders.

[View the story "Smoke causes evacuation of BART station" on Storify]

Earlier post: The agency announced it was evacuating the Orinda station, east of the stranded train. Media reports say the Rockridge station, the first stop west of the tunnel, has also been evacuated. The San Francisco Chronicle's Trapper Byrne reported via Twitter that some passengers on the train were complaining of smoke inhalation and that firefighters were boarding a rescue train in Orinda.

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