WASHINGTON, D.C. – The National Transportation Safety Board issued nine safety recommendations on Tuesday—six of which are urgent— to address concerns about the safety of train control systems that use audio frequency track circuits. The recommendations are a result of the investigation into the deadly Metro crash that killed nine people in June.
During the investigation, the National Transportation Safety Board (NTSB) says it discovered that a failure occurred in which a spurious signal generated by a track circuit module transmitter mimicked a valid signal and bypassed the rails via an unintended signal path. The spurious signal was sensed by the module receiver which resulted in the train not being detected when it stopped in the track circuit where the accident occurred.
The crash happened on the Red Line near the Fort Totten station back on June 22. Nine people were killed, and dozens more were injured.
The NTSB made specific recommendations to the Washington Metropolitan Area Transit Authority (WMATA) and to Alstom Signaling, Inc., the manufacturer of the track circuit modules at the Fort Totten station, to examine the WMATA track circuits and work together to eliminate adverse conditions that could affect the safe performance of these systems. Additionally, the NTSB called upon WMATA to develop a program to periodically determine that the electronic components in its train control systems are performing within design tolerances.
The NTSB’s investigation into the crash is still ongoing and no probable cause has been reached yet. The agency says it is concerned about the safety of train control system circuitry used in comparable rail and transit operation in other parts of the country, and therefore it has recommended that the Federal Transit Administration (FTA) and the Federal Railroad Administration (FRA) advise all rail transit operators and railroads that use audio frequency track circuits in their train control systems about these findings from the Fort Totten accident investigation.