6000-Series train at Fort Totten by Ben Schumin licensed under Creative Commons.

A Red Line train came apart while leaving the Glenmont station on Tuesday in what Metro called a “train-separation incident,” stranding 12 passengers on board for over an hour and suspending service at the station for over four. The transit agency removed all 184 6000-series railcars from service in response. This is the second separation incident in as many months.

The trailing four cars of an eight-car train leaving Glenmont separated in the track crossover just outside the station at approximately 1:04 pm on Tuesday. The train had traveled under 1600 feet before the operator of the train reported that the brakes had engaged and the train was unable to move. Further investigation determined the trailing four cars came apart from the train.

The train separation is the second 6000-series incident in two months. A Red Line train to Glenmont experienced a “pull-apart” outside Union Station on October 9th and resulted in a multi-hour suspension of service between the Gallery Place and Rhode Island Avenue stations.

Metro said in a statement Tuesday that Theresa Impastato, the agency’s Chief Safety Officer, recommended that the agency remove all 6000-series cars from service and keep them out of service “until investigators fully understand the underlying causes and contributing factors involved.” Metro does not have a timeline for its investigation.

The Washington Metrorail Safety Commission issued a statement supporting Impastato’s 6000-series grounding until the cause of the pull-apart is identified. The oversight agency says it will work with Metro to “determine the cause of this event, and whether there are any similarities to or differences from prior train separations.”

A source who spoke with Greater Greater Washington described how the railcars appear to have come apart. The end of the draft bar - the narrow cylinder in the graphic below - apparently detached from the coupler head shown on the left, which is the part of the coupler that secures one railcar to another. The coupler head detached from its railcar, remained attached to the other car’s coupler head, and the two halves of the train separated.

Graphic showing the coupler head and how it connects to the railcar. Image via Metro document.

This separation occurred in a different location than the October incident. On the coupler assembly that separated last month, the coupler head remained attached to the draft bar (the narrower cylinder in the image above), but the draft bar pulled out of the draft gear buffer (the larger cylinder) when it detached from the railcar.

Metro removed all 6000-series railcars from service as part of its investigation into the October incident and performed inspections on the entire fleet, but the cars were quickly put back into service. Eighteen of the first 166 inspected had “potential concerns,” according to the WMSC, and three pairs were found to have had “incorrect hardware” installed.

In a new move, Metro said in its statement Tuesday that they would bring in the original equipment manufacturer of the 6000-series trains “to add technical and engineering expertise” to assist with the investigation. Alstom, which built the cars, delivered them to Metro between 2005 and 2007.

Metro also hired the French rail company in the 2000’s to perform mid-life “major rehabilitation” of the 2000- and 3000-series railcars to extend their lives another 20 years. That work was completed in 2007 and the 2000/3000-series railcars are now substantially the same as the 6000-series.

All 6000-series railcars are expected to be removed from service by the end of Tuesday, and the Metro and WMSC investigations are ongoing. The WMSC’s next scheduled meeting is on January 26.

Stephen Repetski is a Virginia native and has lived in the Fairfax area for over 20 years. He has a BS in Applied Networking and Systems Administration from Rochester Institute of Technology and works in Information Technology. Learning about, discussing, and analyzing transit (especially planes and trains) is a hobby he enjoys.