A June Metro train derailment was caused by a track inspector’s failure to notice a section of misaligned tracks between the Rosslyn and Courthouse Metro stations, officials said after an internal investigation into the incident.
The tracks had widened in that area because the fasteners that hold them down had loosened, officials said.
A track inspector had surveyed that section of the Orange Line track the day of the June 9 derailment but failed to notice the poor track conditions, according to Metro.
“The probable cause of this derailment was ‘out of tolerance track conditions’ including wide gage track conditions [the width between the tracks], loose track hardware, and improper track alignment,” the report said. “These conditions should have been found during track inspections and identified prior to the derailment.”
The alignment of the tracks on that stretch of rail had been measured in January and deemed acceptable, according to the report.
The six-car Orange Line train derailed when one of the front wheels of the third car jumped on top of the rail and the other one dropped to the ground about 20 feet after passing over the bad section of track.
The train dragged for almost a mile in that condition before the operator stopped it after a Metro employee who was on the train noticed bumping and raised the alarm.
The track inspector found to be at fault was suspended for five days, Metro’s standard suspension for a first offense, and has been retrained under a refresher training program the transit agency implemented after the derailment, officials said.
According to the report, the track inspector had completed another refresher course in 2005 and received advanced track inspection training in 2007 and in 2008.
Since the derailment, all of Metro’s 37 track inspectors have completed the new training course, which includes a written and practical exam, according to Metro. The agency has 11 vacant track inspector positions.
Metro’s track department has bought equipment that measures the force of the trains pushing against the tracks to help prevent track shifting.
The transit agency also has ordered a customized “rail geometry vehicle,” which patrols the tracks and uses laser beams to measure whether the alignment is off.
That piece of equipment is scheduled to arrive in 2010.
