Railroad Accident Report
Derailment of Washington Metropolitan Area Transit
Authority Train near the Mt. Vernon Square Station
Washington, D.C.
January 7, 2007

NTSB Number RAR-07/03
NTIS Number PB2007-916303
PDF Document(1 MB)

Executive Summary: On January 7, 2007, about 3:45 p.m. eastern standard time, northbound Washington Metropolitan Area Transit Authority Metrorail train 504 derailed one car as the train traversed a crossover from track 2 to track 1. The accident occurred in an underground tunnel on the Metrorail Green Line near the Mt. Vernon Square 7th Street-Convention Center (Mt. Vernon Square) station at chain marker E2 23+28. The train was traveling about 18 mph as it approached the station.

The train consisted of six cars. The fifth car from the head end of the train derailed. About 80 passengers were on board at the time of the accident. Twentythree
passengers were transported to local hospitals for treatment and released. Emergency response personnel from Washington, D.C., provided the on-scene
treatment and transportation of the injured passengers.

As a result of its investigation of this accident, the Safety Board identified the following safety issues:

• Wheel-truing procedures
• Mitigating measures for wheel climb derailments
• WMATA interdepartmental coordination

As a result of its investigation of this accident, the National Transportation Safety Board makes recommendations to the Washington Metropolitan Area
Transit Authority.

The National Transportation Safety Board determines that the probable cause of the January 7, 2007, derailment of Washington Metropolitan Area Transit Authority train 504 as it traversed a standard turnout track near the Mt. Vernon Square station in Washington, D.C., was a wheel climb on car 5152 that was initiated by a rough wheel surface created when the wheel was trued with a milling machine, the lack of quality control measures to ensure that wheel surfaces were smoothed after truing, the lack of a guard rail on the No. 8 turnout, and Washington Metropolitan Area Transit Authority’s failure to have an effective process to implement safety improvements identified following similar accidents and related research projects.