Partial service was restored Monday between two East Bay stations on a BART line after being discontinued last Wednesday due to a mysterious power surge that rendered nine percent of BART's operating fleet out of service.
The problem is far from solved. The interim peak hour shuttle between North Concord and Pittsburg/Bay Point stations on the Pittsburg/Bay Point–SFO/Millbrae line caused crowding problems on the platform, though it's a shorter trip than provided by the bus bridge that operates during most of the day. But worst of all, the cause of the problem remains a mystery.
"Engineers and outside experts continued Monday to search for the elusive gremlin that’s causing train-damaging power spikes on the rails between the stations, but came up empty," writes Michael Cabanatuan, transportation reporter for the San Francisco Chronicle.
Test your knowledge of electrical engineering: Do you know what a thyristor* is?
All your really need to know is that it is an electrical component "that is stifling the morning commutes for thousands in the East Bay, difficult to pronounce, smaller than a coffee cup lid, hard to find and costs $1,000 apiece," writes Lisa Fernandez for NBC Bay Area.
"While crews tried to sleuth out the cause, workers in BART maintenance shops worked to repair damaged cars, replacing the thyristors," writes Cabanatuan.
[Paul Oversier, BART Assistant General Manager] said 36 railcars were repaired and put back into service Monday, raising the total available to 557 and reducing the number of short trains pressed into service. On an average weekday, 579 cars are typically available.
That should greatly help BART's 440,000 daily commuters who have been crowded on to shorter trains. As noted, rather ironically, in an earlier post about the resumption of D.C. Metro service on Thursday after being shut down on Wednesday to fix electrical problems 50 BART cars were incapacitated that same day.
Cabanatuan, Oversier and Tom Radulovich, president of the BART Board of Directors engaged in an informative hour of dialog on Monday, taking call-in questions from the public on KQED Forum on BART's latest problem, though the discussion included many of BART's chronic problems as well.
*Thyristor: a four-layered semiconductor rectifier in which the flow of current between two electrodes is triggered by a signal at a third electrode.
Hat tip — News Headlines by MTC-ABAG Library
FULL STORY: BART restores partial service to Pittsburg, but mystery remains

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