Independent safety regulators have pinpointed the likely failure that caused two Metrorail cars to unexpectedly detach two weeks ago near D.C.’s Union Station. The incident stranded some 103 passengers for about two hours.
The Red Line cars pulled apart shortly after the train left Union Station for NOMA-Gallaudet University station on Oct. 9. There weren’t any reported injuries.
“Our initial assessment of the evidence suggests that the pull-apart likely occurred due to an improperly torqued bolt. The lack of damage to certain parts of the rail car suggests that the clamping bolt likely worked itself loose over time,” said David Mayer, CEO of the Washington Metrorail Safety Commission.
A follow-up inspection of the coupling devices on other Metrorail cars in the same 6000 series as the cars that detached found other potential problems.
“By the middle of last week, 90% of the fleet had been inspected,” Mayer said during Tuesday’s regular meeting of the independent commission that oversees safety of the Metrorail system.
“Eighteen of the first 166 of those cars that were inspected had potential concerns. Three of those cars appear to have had incorrect hardware installed. Cars with discrepancies are getting additional scrutiny to determine what adjustments, if any, are needed.”
The commission’s investigation into the detaching incident also found fault with Metro’s handling of the coupling device after the failure.
“Our review of the coupler assembly the morning after the train pulled apart demonstrated that Metro had not followed its own investigative procedures regarding the chain of custody for evidence. A bolt clearly had been torqued after the event without communication with and approval from Metro’s Safety Department and the WMSC,” Mayer said.
The commission has given Metro 30 days to produce a corrective action plan to ensure that proper steps are taken to protect the integrity of future safety investigations.