[Scan-DC] Listserv: NTSB Investigates Metrorail Collision

[b_thom at juno.com]

This is from their listserv. The testing must generate lots of radio
traffic.
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From: "NTSB Press Releases" <NTSBPressReleases at NTSB.GOV>
To: RAIL at LISTSERV.NTSB.GOV

************************************************************ 
                       NTSB ADVISORY 
************************************************************ 

National Transportation Safety Board 
Washington, DC 20594 

July 1, 2009 

************************************************************ 

SECOND UPDATE ON NTSB INVESTIGATION INTO COLLISION OF TWO 
METRORAIL TRAINS IN WASHINGTON, D.C. 

************************************************************ 

In its continuing investigation of the June 22, 2009, 
accident involving the collision of two Washington 
Metropolitan Area Transit Authority (WMATA) trains on the 
Red Line in Washington, D.C., the National Transportation 
Safety Board has developed the following factual 
information: 

The examination of factors leading up to the accident 
continues.  Investigators have been conducting nightly tests 
of the train control system at the accident site.  Test 
progress was delayed by some water in underground access 
areas that made it unsafe for technicians to work on 
electrical cables until the water could be pumped out.  The 
components being tested include track impedence bonds, 
wayside cables, and train control system circuitry for the 
track segment between the Fort Totten and Takoma stations. 

As previously reported, initial testing showed that when the 
test train was stopped at the same location as the train 
that was struck in the accident, the train control system 
lost detection of the test train.   Additionally, in 
subsequent testing over the weekend the train detection 
system intermittently failed; data is currently being 
collected to further analyze each component in the train 
detection system.  Investigators are reviewing recorded 
track circuit data for each test configuration. 

Maintenance records show that an impedence bond for the 
track circuit where the accident occurred was replaced on 
June 17th, five days before the accident.  After a post- 
accident review of recorded track circuit data, WMATA 
reported to the NTSB that the track circuit periodically 
lost its ability to detect trains after June 17th; the NTSB 
is reviewing documentation on the performance of that track 
circuit both before and after the June 17th replacement. 

The weekend of July 18th investigators intend to conduct 
sight distance tests using trains consisting of similar cars 
to those involved in the accident.  The tests will establish 
when the struck train would have been visible from the 
striking train.  The previously reported rail streak marks 
consistent with heavy braking were approximately 125 feet 
long, and began approximately 425 feet prior to the point of 
collision. 

The investigative groups have concluded the on-scene phase 
of the investigation except for the Signals Group that 
continues to examine the train control system both at the 
scene of the accident and at the WMATA Operations Control 
Center.   

# # # 

Media contact: 
Bridget Ann Serchak 
202.314.6100 
bridget.serchak at ntsb.gov 

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