During a news conference Tuesday afternoon, Metro General Manager Richard Sarles said it would be premature to guess why the “friction ring,” similar to a brake disc on a vehicle, became disconnected.
Sarles said it is “rare” for one of the parts to fall off. “An investigation will come to the root cause,” he said.
When the friction ring fell off a Blue Line train, there was a spark and smoke. The friction ring landed between the electrified third rail and the running rails of the track, Metro officials said. Two Orange Line trains that were behind the Blue Line train heading in the direction of Vienna were also damaged, Sarles said.
The Blue Line train kept going and passengers disembarked at the Smithsonian station. That train was taken out of service.
Roughly 300 passengers on the Orange Line train behind it were stranded when that train suffered damage to its “collector plates,” which pull power from the third rail, said Dan Stessel, Metro’s chief spokesman.
Passengers were evacuated as emergency personnel made a human chain to help guide them to the Smithsonian platform, D.C. Emergency Response officials said. Streets around the L’Enfant Plaza and Smithsonian stops were shut down as crews responded, and shuttle buses were used to move stranded passengers.
One female passenger experienced anxiety and received medical attention on the scene, D.C. Deputy Fire Chief Kevin Byrne said. Some reports of riders “self-evacuating” from trains streamed onto Twitter, but Stessel said he had no confirmed reports of that.
When smoke was reported on the track, the third rail power was shut off, which caused another Orange Line train to lose power; it had to glide to L’Enfant Plaza where passengers were offloaded, Stessel said. Part of the train was still in the tunnel so some passengers had to move to the front of the train to leave. That train suffered cable damage, Stessel said.
Metro said it has 190 of the 5000 series rail cars in service in its fleet of 1,100. The transit authority spent $383 million buying the rail cars, which have had a history of electrical, software and wheel problems, from CAF Inc. of Spain. Stessel said the trains were delivered to Metro between 1998 and 2003. The Blue Line train that lost the friction ring was last inspected on Dec. 8, he said.
Sarles said the investigation, which will start immediately, will involve examining “materials, running metallurgy tests, examining maintenance records, design of the brake assembly and wayside conditions.” He said no track damage occurred after the incident.