Update, 10:45 a.m.: BART just released a statement on what caused the computer and train-switching problems that shut down the transit system earlier this morning. The agency says the glitch originated with an upgrade to its computer system:
"Yesterday BART implemented a planned infrastructure upgrade to a network server. Twelve hours later this change began to impact the exchange of information between servers, which affected the performance of the computer system the Operations Control Center relies on to monitor train service. Eventually the central computer went off line, which caused the last trains of the night to be delayed upwards of two hours due to the need for train operators and maintenance crews to manually move and lock switches.
BART worked through the night to identify the root of the computer problem and tracked it to the upgrade made the day before. The server was returned to the original configuration and the problem was fixed. Limited train service resumed at 7:18 am and reached full service within 90 minutes.
BART engineers are investigating the technical nuances that caused the problems and will make any needed fixes to prevent the problem from reoccurring.
At no time was train safety compromised. We apologize for the inconvenience to our late-night riders and for the late opening this morning."
Update: 9:30 a.m.: BART reports that it's back up to 100 percent of the capacity after its earlier problems.
It's possible that what commuters are experiencing, though, is less than a smooth trip. Here's Doug Sovern from KCBS via Twitter:
My @SFBART train is "on hold" at Rockridge due to "personnel aligning track manually ahead." Train operator apologizes "for stupidness."
— Doug Sovern (@SovernNation) November 22, 2013
Original post: BART is resuming service after an overnight computer system failure that shut down the system, stranding thousands of people and snarling the early-morning commute.
BART says service is starting again with about half the usual number of commute-hour trains. The agency said the system will be running at full capacity by 9 a.m.