Metro Response to NTSB Advisory
News release issued at 2:03 pm, July 23, 2009
The ongoing National Transportation Safety Board (NTSB) investigation to determine the cause of the June 22 Red Line collision near the Fort Totten Metrorail station has indicated that a second impedance bond or Wee-Z bond (bond #14) at the site of the accident "has been intermittently fluctuating" since December 2007, according the NTSB's latest update.
Investigators still do not know the cause of the accident and Metro is continuing to work closely with the NTSB on the investigation to determine the root cause.
A sampling of the performance data from December 2007 to June 17 found that intermittent "fluctuations" or anomalies were discovered in bond 14, but none that would cause the loss of the track circuit's ability to detect a train. Metro is in the process of analyzing all of the data from the time period for a more thorough review.
Since the accident, Metro has increased the frequency of its track circuit data review from once every 30 days to twice daily and is doing a deeper level of analysis with more stringent requirements. Engineers review computerized reports after each rush hour and investigate every anomaly they see.
"It's important to know that an anomaly does not necessarily indicate a failure in the track circuitry or train detection system," said Metro General Manager John Catoe. "It's like when a doctor does an EKG on your heart. A blip in the data doesn't mean you're having a heart attack, but the doctor may want to conduct more tests."
As part of this more rigorous review, Metro has found track circuits where there are anomalies and are taking immediate actions to correct them. In some cases, the problem can be quickly corrected while others take more time. In the instances where repairs are lengthy, Metro may temporarily take a track circuit out of service to work on a fix. When a track circuit is disabled or turned off for repair, trains slow to 15 miles per hour through the area, maintain radio contact with controllers in Metro's Operations Control Center and remain visible to controllers.
"Though we have found anomalies in other areas of the rail system, we have not found anything that resembles the magnitude of the track circuit problem at Fort Totten," Catoe said.
Maintenance is done on the Metro system daily. However, because of the more frequent and more stringent monitoring, Metro riders may find that track work is being done in more areas on the rail system and that their trains are moving at slower speeds through those areas where Metro track workers are inspecting or repairing track signaling equipment.
"It's like passing though a work zone on a highway. You slow down as you safely pass the road workers," Catoe said.
Metro realizes that this may cause more inconvenience for its riders, but the additional review and maintenance are part of working to fulfill the NTSB's recommendation of instituting greater review of track circuits and eventually developing a real-time monitoring system. Metro is working with an existing contractor, ARINC, and other outside vendors on developing that backup system.
"Our Metrorail system is under greater safety scrutiny and review than ever before," Catoe said. "Though it may seem like an inconvenience to our riders, it is temporary, and in the long run, it will result in an even safer Metrorail system."
July 23, 2009; 2:05 PM ET
Categories: Metro | Tags: metro accident, ntsb, red line
Save & Share: Previous: NTSB's Third Update on Metro Red Line Crash
Next: Accident at N Capitol St. NW and New York Ave. NW
Posted by: blah1233242 | July 23, 2009 2:45 PM | Report abuse
Posted by: Edgemoor | July 23, 2009 4:47 PM | Report abuse
The comments to this entry are closed.