BART officials on Wednesday blamed the failure of brake on the test train car last week on a chain reaction that began when the power supply to monitoring equipment short circuited.
The cord that supplies power to the monitoring equipment frayed in Hayward on April 21, when testing officials closed a bay door on it, officials said at a news conference. The frayed cord triggered a short circuit in the train car auxiliary power supply, officials said. And that auxiliary power supply operates a pump that provides hydraulic brake fluid to the car.
The operator, apparently unaware of the loss of power, continued to operate the brake until the fluid was exhausted, officials said.
The train ended up crashing at about 6 to 8 miles an hour.
“Stuff happens,” said Tamar Allen, BART’s chief maintenance and engineering officer. “What you do when stuff happens, is you learn things.”
She called it a “normal occurrence” of testing and a “very low speed crash.” She also said it wouldn’t have happened on a regular BART car.
But both she and John Garnham, director of the “Fleet of the Future,” vowed to upgrade BART’s alert system so that operators would be more aware of similar equipment failures.