Government investigators probing the cause of Washington’s deadly Metro accident this summer issued an urgent warning to transit systems nationwide Tuesday that they have found a flaw in a commonly used safety monitoring system that could give a false signal and increase the risk of a crash.
National Transportation Safety Board (NTSB) officials said it was too soon to declare the exact cause of the June 22 crash, which killed nine and injured dozens.
However, the problems uncovered with the audio frequency monitoring system warranted alerting other transit systems without delay. The flaw, investigators said, could cause the alert system to falsely report that an occupied track is clear.
In the crash this summer, a train slammed into the back of a stopped train on the Red Line. Investigators have determined that the audio frequency track circuits or liaison device that communicates information such as speed and distance between trains, the operations center and the tracks “periodically lost its ability to detect trains.”
The NTSB sent nine safety recommendations six of which were deemed urgent to the Washington Metropolitan Area Transit Authority (WMATA), which runs Metro; the Federal Transit Administration (FTA), which funds transit agencies; the Federal Railroad Administration (FRA), which oversees freight and passenger trains including Amtrak; and Alstom Signaling Inc., which manufactures the component of the signaling system in question.
In its letter to Metro, the NTSB issued two urgent recommendations advising that the transit agency to examine all of its track circuits and develop a program to determine that the system is functioning correctly.
The FTA also received two urgent recommendations, including one to advise all transit operators about the findings of the NTSB investigation with regard to the circuits. The FTA sent a letter Tuesday night to transit agencies and state oversight agencies advising them of the NTSB’s recommendations and will later conduct an in-depth survey to determine which transit systems use the same circuits.
The NTSB has not concluded its investigation into the crash, NTSB Chairman Deborah A.P. Hersman said.
“After only three months, this complex investigation is far from complete, so we are not ready to determine the probable cause of the accident on WMATA,” she said. “However, our findings so far indicate a pressing need to issue these recommendations to immediately address safety glitches we have found that could lead to another tragic accident on WMATA or another transit or rail system.”
Metro General Manager John B. Catoe Jr. said Tuesday night that his agency would implement the NTSB’s recommendations.
“The NTSB has identified a symptom of the problem with the track circuit, but not a root cause or a solution,” Mr. Catoe said. “We are doing everything we can to make our rail system as safe as possible. The NTSB still has not identified a probable cause for the accident. They made two recommendations, and we will implement those recommendations. In fact, we began to do so weeks ago.”
After the crash, Metro immediately began checking all of the track circuits and is checking its system on a daily basis.
Mr. Catoe told The Washington Times in July that Metro was checking everything manually but would work to implement an electronic system that would digitally monitor and automatically create trouble tickets for the system. He said the price tag would be almost $1 billion.
That digital monitoring program could be used by other rail systems across the country, Mr. Catoe said. He predicted that whatever problems with the 30-year-old computer system were identified could have consequences for transit systems nationwide.
“We’re not the only one with this type of system. Most rail operations around the country have a similar system to this,” said Mr. Catoe, who at the time insisted he was speculating and distanced himself from the NTSB investigation.
“If they find, let’s say, that there’s a defect in the part, then you have to look at all the parts around the country, because there’s only two manufacturers of those parts,” he said.
The NTSB sent a letter to Alstom urgently recommending that it assist Metro along with other transit systems and railroads that use its product in their testing and repair of the component. Alstom did not return a telephone call seeking comment Tuesday night.
The FRA also received two urgent recommendations. Spokesman Warren Flatau said the administration would comply immediately. He said that after the accident, the agency conducted a review, and of the roughly two dozen passenger systems that the agency oversees, few are thought to use such a signaling system.