Ruben Payan says at the time there had been 3,000 loss of track occupied detections and 9,000 loss of track vacant PER WEEK on 100 different track circuits throughout the system, and were being ignored due to their frequency. The struck train was in manual mode against the rules. Misunderstood methods on how to verify installation of new track circuilt equipment. This sounds frustratingly stupid, it's not so simple anymore.
Robert Sumwalt is harping on manual mode of the struck train being a serious factor. My observation is this has nothing to do with the failure of the system to detect trains but he's going on and on about it. He appears to think that manual mode disables PTC which is not the case.
Anyway the hearing is going on now at http://www.ntsb.org/.
What's the concept and design behind the "guarded switch" that WMATA mentioned in this report?
Thanks!!
Following the Fort Totten accident last year that killed 9 and hurt 80, a press release has been made July 26 in advance of the NTSB findings which are scheduled for today, July 27.
Complete replacement of 1000-series cars with 300 new 7000-series cars. The total order is 428 with the remainder dedicated to the new Silver Line to Dulles Airport.
Within a month, install rollback protection on all cars including all 1000-series until they are replaced (interesting).
Re-training and safety culture for all employees, including a test of rail operators for sleep disorders. This last thing is a red herring. Disregarded or ignored by nearly everyone is that the DC Metro is a fully automatic system and under normal running, the rail operators only open and close doors, watch for emergencies to push the emergency stop button, run trains manually in icy weather, and shepherd the passengers. Of course since the accident all trains have been manually run but this is not normal operation. I don't get how when Central misdirects a train onto the wrong track they blame the train operator/door operator, like when last month the Orange line was directed to Blue line by mistake, it was Central's fault, not the operator.
Established test procedures to identify track circuits susceptible to parasitic oscillation, which is under review by the NTSB. This is the first time I've seen this term. The track workers were calling this "bobbing" and it happened all the time on the new bonds. If this is the cause of the accident I say shame on WMATA for allowing it.
Began work simultaneously, on a real-time 24/7, automatic track circuit monitoring system inclusive of loss of shunt, which is scheduled to be implemented in December 2010. I think without signal "bobbing" this would not be necessary and I question the logic behind this except that WMATA has a crony at ARINC, the design/build contractor.
When replacing impedance bonds, Metro installs a track circuit module from the same manufacturer, solely as a precautionary measure. This was the over-arching comment made by track workers at last Spring's hearings, that the new bonds are not compatible enough with the old system. I am interested to see if this is really the cause of the June 22 accident since the track workers are so convinced.
More is below, and watch for today's NTSB report.
http://www.wmata.com/about_metro/news/PressReleaseDetail.cfm?ReleaseID=4579
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