Urgent Safety Concerns7/14/2009 [PDF]
Re: Urgent Safety Recommendation by the National Transportation Safety Board
I write to you today to follow-up on an urgent recommendation the National Transportation Safety Board (NTSB) has made to the Federal Transit Administration (FTA) as the result of a preliminary analysis of the causes of the deadly Washington Metro Red Line heavy rail collision on June 22, 2009. As you know, nine persons died and 70 persons were injured as the result of this two-train collision.
The NTSB has determined, as a preliminary matter, that the Washington Metro train control system was susceptible to a single point failure. The system did not fail-safe and stop the train when train detection was lost. The NTSB has concluded that Washington Metro's train control lacked adequate safety redundancy that would have included timely alerts of system failures and compensation for intermittent failures or other anomalies in train detection.
The NTSB has asked that we immediately issue an advisory to all transit rail operators around the country to address the potential safety vulnerability. Specifically, we are asking that all train operators that have train control systems capable of monitoring train movements determine whether their systems have adequate safety redundancy if losses in train detection occur. If a system is susceptible to single point failure, we urge you take corrective action immediately to add redundancy by evaluating track occupancy data on a real-time basis to automatically generate alerts and speed restrictions to prevent train collisions.
We at the FTA and the U.S. Department of Transportation hold safety as our number one priority. I request that you focus immediate attention on this important safety concern. For the purposes of verification, we will be following-up shortly with requests for information on specific train control systems and what compensating systems you have been able to develop if you have determined that a single point failure could occur.
We also expect to serve as a clearinghouse to share information regarding industry best practices in addressing this issue.
Thank you very much for your immediate and priority attention to this matter. Please call me directly on (202) 366-4040 if I can be of further assistance.
Peter M. Rogoff