during his interview on November 10, 2015. This prompted him to sound the train's horn and broadcast a radio advisory that his train was approaching and would be passing the SEPTA train.
As he listened to the 6-minute radio conversation between the SEPTA engineer and the dispatcher, the Amtrak engineer continued to operate his train at or below the maximum authorized track speed, and he remained cognizant of the signal indications affecting immediate train operations. The engineer's throttle manipulation that accelerated the train to 106 mph was initiated about 27 seconds after the last radio transmission between the SEPTA engineer and the train dispatcher at 9:19 p.m.[1] Clearly, this action was not appropriate at that time given that the maximum authorized speed was 80 mph and the speed-restricted curve at Frankford Junction was coming up. But if he had traveled another 2 miles, going through the Frankford Junction curve and an adjacent curve at appropriate speeds, he then would have been authorized to operate the train at 110 mph, a speed that he was accustomed to traveling at numerous points along the route.[2]
Investigators used event recorder data to derive the engineer's manipulation of the throttle.[3] The method by which the engineer manipulated the throttle to increase the train's speed to 106 mph was consistent with his description of how he normally made a significant increase in speed when it was appropriate to do so. He told investigators that he typically accelerated with full throttle and then backed off as he approached his target speed. Event recorder data indicated that he did execute this procedure with a slight throttle manipulation when the train reached about 95 mph. Therefore, NTSB concludes that the Amtrak engineer initially accelerated his train to a high rate of speed in a manner consistent with how he habitually manipulated the controls when accelerating to a target speed, suggesting that he was actively operating the train rather than incapacitated moments before the accident.
The NTSB examined the possibility that as a result of diverting his attention to the extended radio communications between the SEPTA engineer and the dispatcher, the Amtrak engineer may have lost situational awareness. His loss of awareness, combined with the darkness, may have led him either to believe he had already passed the curve at Frankford Junction or to forget about the curve.
- ↑ Research on distracted driving found that potentially unsafe mental distractions can persist for as long as 27 seconds after completing a highly distracting task. See: David L. Strayer, Joel M. Cooper, Jonna Turrill, James R. Coleman, and Rachel J. Hopman, Measuring Cognitive Distraction in the Automobile III: A Comparison of Ten 2015 In-Vehicle Information Systems (Washington, DC: American Automobile Association Foundation for Traffic Safety, 2015).
- ↑ There are many sections of track in the Northeast Corridor where the maximum authorized speed is 110 mph or greater.
- ↑ The throttle position was not recorded due to loose wires to the event recorder. Investigators derived the throttle movements from performance calculations of recorded speed and locomotive characteristics.
8
