WMATA has released a statement saying that Metro fixed the computer glitch that stopped rail service twice over the weekend. According to the statement:
The cause was determined to be a failed module in an information management network device. Once the computer module – about the size of a pizza box – was replaced in the early morning hours before the start of train service, the errors that had occurred in the system stopped.
Strange pizza box detail aside, Metro says everything is all better.
The weekend malfunction prevented operators from seeing where trains were in the system. While train conductors could still see who was ahead or behind them because of a separate set of controls, Metro decided to have all trains pull into stations while the issue was resolved. Trains sat in stations for about 45 minutes on Saturday afternoon.
Then it happened again on Sunday morning, from about 1:30 a.m. to 2 a.m.
Metro has previously had computer glitches that stopped service -- though not system-wide -- including one in March of this year.
The WMATA-critical Unsuck DC Metro blog wondered what was up with the system's backup and redundancies that are meant to prevent the kind of system failure that occurred over the weekend.
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WMATA spokesman Dan Stessel said the pizza box module hardware issue was enough to knock out information management system, but it was actually only a partial failure, "so [the backups] didn't kick in."
Making the system more robust, Stessel says, means working to make sure that even partial failures are trigger the backup system.