Circuits on all Metro train tracks throughout the Washington, D.C., system will now be inspected after investigators found an "anomaly" in one of the circuits close to the site of a crash that killed nine riders.
"We do not know if the circuits had anything to do with this accident, but we won't just sit back and wait for someone to tell us," John Catoe, general manager, said today at a meeting with board members, according to a statement from Washington Metro Area Transit Authority. "We're going to be proactive and get out there to test all of them."
About 3,000 circuits will be get a closer look during the next few weeks, Catoe said.
On Thursday, investigators were also interviewing the operator of the train that was violently struck by another train Monday evening. The train operator was released from the hospital Wednesday and will be questioned by teams trying to learn more about the accident.
Investigators on the train track Wednesday found that a key circuit monitoring 740 feet of the track near Monday's derailment may not have been operating as it should have. The find raised the possibility that the Metro train that crashed into a stopped train may not have gotten the indication to slow down.
Investigators tested six circuits between the two stations where the crash occurred. Five of those performed as expected, according to National Transportation Safety Board investigator Deborah Hersman. But one circuit showed what Hersman described as an "anomaly."
The NTSB has now put a stand-in train on the track to conduct additional tests.
Circuits along Metro tracks are a critical part of the automatic train control system. They let trains know how fast to go and provide them with information about whether there's another train up ahead. The computerized system is designed to keep trains from coming within 1,200 feet of each other.
Investigators have determined that the train was indeed running on automatic mode when it crashed and are investigating why built-in safety features of that system did not prevent the accident.
Since the crash, Metro operators have been running trains manually.
"What causes us concern the most is the fact that this was not supposed to happen," Jackie Jeter, president of Amalgamated Transit Union Local 689 said Tuesday. "There are safety mechanisms that are on place on the trains to prevent this type of accident. And, for me, as president of the union and as a train operator, I have to wonder why didn't those safety mechanisms kick in and prevent it."
Train recorders will provide insight into what happened as the information is evaluated over the next few days, former National Transportation Safety Board investigator Barry Sweedler said. The train that was hit had several recorders on it, but the one that collided into it didn't have any.
Hersman of the NTSB said Wednesday it appeared the train operator braked 300 to 400 feet prior to the crash site. NTSB investigators at the scene found "bluing" on the track, indicating emergency braking. They don't yet know how fast the train was going when it collided with the other, but said they will, at some point, be able to ascertain that information.