The National Transportation Safety Board (NTSB) confirmed that train control systems failed during investigative tests being carried out to determine the cause of the Washington DC train crash on Monday that left nine dead.
Two Washington Metropolitan Area Transit Authority (WMATA) trains collided on an above ground section of the Red Line metro railway in Washington DC at around 5pm local time when a moving train crashed into the back of a stationary one.
THE NTSB investigators have conducted tests at the accident site with a similar train and found that when the train was stopped at the same location as the train which was crashed into, the train control system lost detection of the test train.
The investigators said metal to metal compression streak marks on both rails of the track for ending near the point of impact were consistent with heavy braking.
The NTSB said the train control system is complex and will require a thorough investigation of all components. Investigators are continuing to examine trackside circuits and train control system data to understand how the train control system functioned on the day of the accident.
Investigators have collected recorder information from the struck train. Data was recovered from eight of the nine recorders on the struck train but could not be downloaded from one recorder. Two of the eight recorders did not contain data related to the accident and some data collection ended before the accident for undetermined reasons. The accident data is now being examined by investigators in the NTSB’s laboratory. The striking train did not have any onboard accident data recorders.
The operator of the struck train said he had been driving the train in manual mode during his entire shift that afternoon. He said that he saw a train in front of him and stopped to wait for the train to clear. While stopped, he said that he felt a hard push from behind.
Investigators are continuing to document evidence at the accident site and intend to conduct sight distance tests, using similar trains to those involved in the accident.