Metro officials still were not sure Sunday evening why a computer system that monitors all of the trains in the system stopped working twice over the weekend, stranding passengers at stations for 40 minutes on Saturday afternoon and temporarily halting trains early Sunday morning.
Metro spokesman Dan Stessel said that when the computer system went down both times, trains were held “in an abundance of caution.” The systems that provide power to the trains, control track switching and ensure that trains are a safe distance apart are all separate and were not impacted.
“This is a system that is necessary for the effective movement of trains,” Mr. Stessel said. “It is a high priority for us to identify the cause” of the problem.
Forty-four trains with doors open halted at stations from about 2:10 to 2:50 p.m. on Saturday afternoon. Because there were fewer trains moving when the computer system went down the second time at about 12:30 a.m. Sunday, controllers radioed individual trains, allowing them to move while the system was still out of commission. The system came back up at around 1 a.m. Sunday.
Mr. Stessel said system shutdowns like this weekend’s are “rare, but not unprecedented.”
As of Sunday evening, there had been no further issues.
Meanwhile, computer technicians are working to determine what happened.
“They are looking at software, going through the logs, and working through diagnostics to try to isolate the problem,” Mr. Stessel said.Metro announced there will be additional supervisory staff on hand during the Monday commute so they can respond to any more technical issues quickly.
July has been a difficult month for Metro. On July 6, a train derailed outside of the West Hyattsville station because of a “heat kink” in the tracks caused by triple-digit temperatures. Crews worked throughout the weekend to repair 1,300 feet of track, and suspended Green Line service north of Fort Totten.
On July 3, nearly 200 Metro passengers walked on the tracks when their train lost power near the College Park station and no one responded for 45 minutes.