
‘Negative’
courtesy of ‘lorigoldberg’
NTSB sent out letters yesterday to WMATA, Alstom Signaling, Inc, Federal Transit Administration and the Federal Railroad Administration. Each letter is slightly different but they all describe what NTSB believes to be the root cause behind the June 22nd Red Line crash.
Alstrom Signaling acquired General Railway Signal, the company that manufactured the WEE-Z bonds used in the metro system and installed in the 1970s at the Ft. Totten section of the red line. These are the devices used to sense and signal the presence of trains on the line and what have been suspected to be the root cause of the June collision.
The letter states “the investigation is ongoing” but confirms that these WEE-Z bonds, and the train sensing signal, continue to be the prime suspect. Immediately after that disclaimer NTSB says the following:
[P]ostaccident testing showed that the track circuit at the accident site lost detection of train 214 when it stopped at the location where the collision occurred. Because the automatic train protection (ATP) system was not detecting train 214’s location, the following train (train 112) did not receive a command to slow or stop in order to maintain train separation.
After that point we get into some pretty hard-core geek speak, but if you’re interested I’ll do a little translation.



















