The problem happened inside the Berkeley Hills Tunnel which passes through the East Bay Hills into Oakland north of the Caldecott Tunnel, stopping the train between the Orinda and Rockridge BART stations. BART officials say that at one point, they tried to send a rescue train filled with firefighters out to the disabled train but couldn't get to them.
BART was eventually able get the disabled train to Rockridge station where the passengers were evacuated. People who got off the train told ABC7 News it was tough to breathe. People could be seen being carried off the train on stretchers, some wearing oxygen masks. Eleven people were treated at the scene; nine of them were taken to area hospitals.
Most people were able to walk off the train under their own power, but many were shaken and said it was a scary situation. One mother recalled having to play a Barbie movie on her phone to distract her 7-year-old daughter from all the commotion. Another woman said she had to take a Xanax to calm down. A lot of people said it would be a long time before they boarded another BART train.
Approximately 700 people were stuck on the train for about one hour. Many recalled seeing their cars filling up with smoke and seeing passengers having trouble breathing. The Oakland fire battalion chief said it was probably brake dust in the air that affected some of the riders.
After the incident, some complained that they weren't able to open the doors to ventilate or evacuate the cars, but BART says that is a standard safety procedure.
"When the ventilation system starts in the tunnel, it's an automatic closure of the doors and that is for the safety of the personnel on the train as well as the firefighters responding," Oakland Fire Chief Melinda Drayton explained.
Drayton said people cannot be walking on or near the tracks when rescue trains enter the tunnel, so in situations like that, passengers have to wait inside the train.
BART spokesperson Alicia Trost just happened to be among the hundreds of of people that go through the Orinda station on the way to work or school, who got stranded because their trains were stuck behind the one disabled in the tunnel.
Many people also expressed frustration with BART over a lack of communication about what exactly was going on and what their options were.
BART says an electrical short in one of the train cars caused the brakes to engage while the train was traveling at high speeds. They are continuing to investigate the incident.
ABC7 News reporters Amy Hollyfield, Laura Anthony and Lyanne Melendez contributed to this report.