Investigators have preliminarily ruled out system error, but they have determined that both train operators received “zero speed” commands and complied. Such a command means the operator should stop the train and remain stationary.
However, the operator of the striking train, for reasons that are unclear, then moved forward without having received permission from the rail operations control center, according to David Mayer, chief executive of the Washington Metrorail Safety Commission.
“There’s no indication that there was that permission” to move, Mayer said. “We know the train moved, and we know the train had a zero-speed command. At this moment, it isn’t productive to get into the head of this operator or to understand this particular train operator.”
Brian Wivell, political organizer for Amalgamated Transit Union Local 689, which represents train operators, said the union would not comment until it had all the facts in the incident.
Metro spokesman Dan Stessel said both operators are being held from driving duties, which is standard procedure during a crash investigation. He said Metro hasn’t announced any findings that point to a cause of the crash.
The incident involved out-of-service trains returning to their respective rail yards after having provided special late-night service following the Washington Nationals’ playoff game.
And while there were no passengers aboard and the operators’ injuries were minor, commission officials said the crash revealed a troubling flaw in Metro’s safety controls that could affect future crashes involving potential operator error.
Metro is under a “Corrective Action Plan” from the Federal Transit Administration to come up with a backup system to prevent trains from moving without authorization. The action plan, which was inherited by the safety commission when it assumed oversight from the FTA, was ordered to correct a flaw first revealed by a National Transportation Safety Board investigation seven years ago and the FTA in 2016.
Metro has not completed the plan, the commission said.
“[The Washington Metropolitan Area Transit Authority] has not fully implemented sufficient protections against the unauthorized movement of trains with zero speed commands,” the commission said in a statement.
The commission said it plans to hold a “technical summit” with Metro about the issue. Mayer said he plans to discuss ways Metro technicians might be able to engineer an onboard security system that would force trains to stop and cede more direct control of them to the operations control center.
“The focus of any safety investigation isn’t blame,” Mayer said. “The focus of a safety investigation is understanding what happened, trying our best to understand why it happened and most importantly working to prevent it. So that’s where our focus is.”
Metro said it’s unaware of a transit system similar to Metro that has successfully implemented the type of technology Mayer raised.
It’s “unclear whether we will find a feasible solution,” Stessel said, “but we will absolutely cooperate with [the safety commission] and participate in their engineering summit.”
The crash occurred at 12:54 a.m. Monday, minutes after Metro had finished carrying fans home from the late-ending Nationals playoff game. One of the six-car 3000-series trains was headed back to the New Carrollton rail yard and the other was headed to a storage area behind the Largo Town Center Metro station, where they were to be prepared for the morning commute.
Both trains were on the same eastbound track when they received zero-speed commands from the Metro signal system because of a train ahead. Mayer said the command required both trains to wait for permission from the control center before resuming their trips. Once a stop command is given, an automatic train protection system limits the trains from going faster than 15 mph.
Metro officials said Train 700 did momentarily stop before it continued forward and into the rear of Train 755 at 11 mph. Radio traffic and other transmissions show the driver did not get permission from the control center to press ahead, and Mayer said neither aging train had cameras onboard that record the nose of lead cars and the actions of drivers. The 3000-series rail cars are among Metro’s oldest.
The lead car of Train 700 sustained “substantial damage” to its exterior and all of its furnishings, Mayer said. Equipment under the train broke in the wreck, he added.
Inspections of the track, as well as logs and other evidence, showed that train controls and safety systems functioned properly, Mayer said.
“The engineering elements in the system as far as the investigation has determined so far performed as they were supposed to be,” he said.
After being treated and released from hospitals, both train operators took routine toxicology tests and were interviewed by investigators. Mayer did not disclose what those interviews may have revealed but indicated that nothing showed the crash was purposeful.
“I have no reason to believe that this employee was anything other than any employee attempting to provide good train service and do what he thought was appropriate,” he said.
The commission’s goal beyond determining cause is preventing future crashes, Mayer said. He told commission members he would ask Metro to convene engineers to see if an “engineering backstop” or security device like a numeric keypad could be installed on older series trains. The keypad would require an operator to get a code from the Rail Operations Control Center before a train could move while under system orders to halt.
“It’s not unique to Metrorail that a train can move under zero-speed commands,” Mayer said. “What we just want to make sure is that when a train is moving under zero-speed commands that it’s done safely and appropriately.”
A keypad security system is slated to be added into Metro’s latest model of trains, the 7000 series, but Mayer said he doesn’t know if it could also be retrofitted into Metro’s older rail cars such as the 3000 series.
Metro has several series of rail cars it uses to shuttle more than 600,000 passengers each weekday, including cars that date as far back as 1982.
“They’re going to be with us for a while, and we want to understand if there’s anything we can do to backstop the administrative command,” he said.
Commission Chair Christopher Hart said the panel is doing what it’s supposed to do, proposing safety upgrades even before the crash investigation — which could take more than 60 days — had concluded.
“Our general principle, even as we investigate, is if we see something warrants immediate attention we don’t wait for the [conclusion of] the investigation to implement,” said Hart, a former chairman of the NTSB.