Metro reveals possible cause of Green Line train separation

WASHINGTON — For the first time Thursday, Metro General Manager Paul Wiedefeld revealed a possible cause of the decoupling of a Green Line train last week.

Wiedefeld says that while the investigation is still ongoing, one anomaly found so far is moisture in a pneumatic line that is a part of the coupler system.

“They have eliminated things, so we know there was no issue with the coupler itself, it was not broken or anything of that sort, the cars were aligned correctly … one anomaly we’ve found is some extra moisture in some lines — this a pneumatic sort of coupling thing that occurs, so basically it’s getting air, and there’s always moisture and air, and then there’s a system that takes that moisture out,” Wiedefeld told reporters following Metro Board committee meetings.

On Jan. 6, the second and third cards of the Green Line train separated near the Navy Yard station during morning rush hour. The train automatically stopped, but the cars ended up about 18 inches apart.

Wiedefeld says the Federal Transit Administration, internal Metro safety groups and external experts in the coupling system are reviewing the incident to figure out what caused the decoupling and how to prevent it from happening again.

“They’re doing obviously a very thorough examination, so we don’t have anything definitive yet,” Wiedefeld says.

“They did note some additional moisture, so we’re tracking that further,” he says.

Wiedefeld has ordered a review of similar coupler systems on other cars “just to see if there’s any issue.” He says the investigation has shown the train appears to have been attached correctly when it left the yard.

Wiedefeld says the safety system that automatically applies the brakes in each car of the train performed as it should.

Riders on the train remained in the tunnel for about 30 minutes until the train was pushed back together and pulled into the Navy Yard Station where the train was taken out of service. Other riders were impacted by single tracking delays caused by the decoupling.

The incident was the latest complication for the beleaguered transit agency, which is working to restore rider confidence.

Service and equipment failures have plagued Metro over the past year, including the L’Enfant Plaza smoke incident in January 2015 that led to one woman’s death. Also, there was a derailment in August that caused major delays, and a transformer fire in September at Stadium-Armory.

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