Experts Suspect Failure Of Signal System, Operator Error
Experts familiar with Metro's operations focused last night on a failure of the signal system and operator error as likely causes of yesterday's fatal Red Line crash.
Metro was designed with a fail-safe computerized signal system that is supposed to prevent trains from colliding. The agency's trains are run by onboard computers that control speed and braking. Another electronic system detects the position of trains to maintain a safe distance between them. If they get too close, the computers automatically apply the brakes, stopping the trains.
These systems were supposed to make yesterday's crash impossible.
Developing story at Washingtonpost.com