Riders wait to board a Metro subway train in Washington. REUTERS/Kevin Lamarque/Files  

Metro officials are investigating why a Green Line train carrying passengers separated as it approached the Navy Yard station Wednesday morning causing delays during the busy commute.

Metro spokeswoman Sherri Ly said a coupler between the second and third cars of the six-car train disengaged as it approached the station around 8:12 a.m. She said the train immediately stopped and the operator conducted an inspection. No injuries were reported, but the incident caused service delays for anxious passengers.

Metro officials discovered the cars, both 3000-series, separated by about 18 inches. Ly said the cars were recoupled and the train moved a short distance into Navy Yard, where passengers transferred to another train.

Officials with the Federal Transit Administration, now responsible for overseeing the safety of Metro’s rail system, were notified about the incident and dispatched their own investigator to the scene.

“With direct FTA oversight of [Washington Metropolitan Area Transit Authority] Metrorail, passengers can be assured the WMATA-led investigation into today’s Green Line train decoupling incident will be thoroughly scrutinized and questioned before being accepted,” FTA said in a statement, adding that the agency reserves the right to launch its own investigation if officials think one is warranted.

Federal officials assume responsibility for Metro safety

Metro is expected to submit its preliminary report into the incident to FTA within three days and a final report within 30 days.

Darran Davis, 31, of Camp Springs, Md., was riding in the first car of the affected train when it came to a “pretty abrupt halt.” The operator announced over the intercom that the train had separated, he said.

“He said ‘attention everybody, this train has come apart. We’re waiting on a crane,’” Davis said.

Davis said it was not immediately obvious to riders what happened.

“It was confusion. You heard people kind of muttering, ‘What? The train came apart? What’s going on?’” Davis said.

Ly said the affected train was taken out of service for inspection and investigation. As a result of the incident trains were forced to share a track between Anacostia and Navy Yard until the train could be moved.

She added that there was no risk to passengers in the incident.

“Brakes on all six railcars engaged and the train came to a safe and complete stop when the uncoupling occurred,” she said. “As such, there was no immediate risk to anyone aboard the train. This type of incident is extremely rare on our system.”

Metro board chairman Mortimer Downey said he was aware of the incident, but did not have any additional details.

“I’m not going to attempt to guess what happened, but it’s obvious that this is not what trains should do,” he said.

Aja Davis, 30, of District Heights, Md., was toward the back of the detached train. She said the train initially came to such a hard stop that she fell on to another passenger, and several others lost their balance.

She said riders sat in the tunnel for more than 20 minutes wondering aloud what had happened. They didn’t hear an announcement over the intercom, but the train did not lose power, she said. Eventually, an operations manager came on board and told riders the train had experienced an “undesired uncoupling.”

Davis was floored by the explanation of the malfunction Wednesday.

“How in the world did the train detach?” she asked in a phone interview. “The first priority should be not crashing. Second should be ‘don’t detach.’”

In a message to riders Wednesday, Metro apologized for the incident and said the results of the investigation would be released by the end of the month and could possibly come earlier “depending on the urgency of the announcement.”

“If we find something that is more urgent then we will not hesitate to make the public aware of that sooner,” said Metro spokesman Dan Stessel.

The Metro board’s Safety and Security Committee, which would review such incidents, has a regularly scheduled meeting Jan. 28, but several committee meetings are scheduled for Jan. 14. The full board also is scheduled to meet in executive session on Jan. 14.

Stessel said the investigation would center on whether the cars were properly coupled, whether the couplers functioned properly and whether they may have been damaged. The cars disconnected to the point where the train’s operator could stand between the two portions of the train, he said.

In the case of an uncoupling, he said, each of the cars’ emergency brakes engage as a safety feature. Heat and electricity is not affected, but PA system messages do not transfer between the two sections of the train. The operator is responsible for informing passengers in each car what has happened.

If the train can be recoupled, as in the case Wednesday, the train is brought into the station, the passengers are let off, and the train is taken out of service and moved to a rail yard. Plan B is to move the separate portions of the trains on their own, Stessel said.