Another brake piece has fallen off a moving Metro train, an outside safety group disclosed Thursday, the fifth incident in less than a year.
The Tri-State Oversight Committee noted the equipment failure and safety problem in a report to the Metro's board of directors and said they have formally requested that Metro start an investigation into the cause of the persistent problems.
"We all want this resolved as quickly as possible," the committee's chairman James Benton told The Washington Examiner.
The equipment known as a friction ring is essentially like a brake disc on a car. It is needed to stop the rail cars. But problems with it can also cause trouble just by falling from the train, causing damage to the track or becoming an obstacle to other trains.
In this case, the piece appears to have broken off on Nov. 3, according to Metro. A Red Line train operator noticed the ring on the tracks between the Van Ness and Tenleytown stops about 6:15 p.m. that day, Metro spokesman Dan Stessel said.
Agency officials found several bolts and the ring alongside the track.
The agency later determined that the friction ring had fallen off a 1000-series rail car from a previous train, apparently earlier that day, Stessel said.
The failure -- and its discovery -- did not cause any injuries or affect train service, Stessel said. Another broken ring last December, by comparison, caused damage to two following trains and trapped about 300 riders underground for more than two hours.
The cause of this latest case has not been determined, Stessel said, but it points to more questions about how widespread the problem may be at the transit system.
The first case of the rings breaking off in service came last December with a 5000-series car. Metro admitted last March that the agency had known since 2006 about the problems with the brake equipment in the 5000 series and even had a plan to replace it. But the agency failed to swap out the equipment because of a lack of funding and kept cars running on what board member called "borrowed time."
But equipment also broke or fell off 2000- and 3000-series rail cars that use a different system and manufacturers. The latest ring broke off from a 1000-series car, a different model rail car altogether. Benton also noted that different parts seem to have failed, from bolts coming undone to the rings actually cracking.
The Federal Transit Administration studied the previous four cases in a recent audit of Metro safety problems and had noted that Metro's actions had led Metro's staff to "believe that future issues with the friction rings are unlikely." The audit, which was made public Nov. 28, was written earlier and made no mention of the latest case.