1.4.1 Loss of Situational Awareness
Situational awareness is defined as "the perception of the elements in the environment with a volume of time and space, comprehension of their meaning, and the projection of their status in the near future." Informally, it is "knowing what's going on."[1]
In this accident, the engineer may have lost awareness of which curve he had traveled through just before he accelerated his train to 106 mph. Immediately following Frankford Junction is a right-hand, 60 mph curve. Two miles before that curve there is a similar right curve near MP 83.5 with a maximum speed of 65 mph. The engineer would have had to operate his train similarly around both right curves. Moreover, each curve is followed by tangent (straight) track that allows the engineer to accelerate to significantly higher speeds. The right curve before the derailment location was followed by tangent track with a maximum operating speed of 80 mph, while the right curve immediately after the derailment location was followed by a 110 mph maximum speed. Given that the two curves were similar and the engineer's attention was diverted to the radio conversations about the emergency situation with the SEPTA train, he may have confused the right track curve preceding Frankford Junction with the right-hand curve following it. In that case, he would have believed it was appropriate to increase his speed to 110 mph after transiting the first curve.
Furthering the potential for error, the engineer was operating at night when there were fewer visible external cues to help him determine his location. According to the engineer's interview and the forward-facing video, neither the elevated bridge at Frankford Junction (which served as a cue to begin decelerating before the curve) nor the curve itself would have been visible when the engineer began accelerating. (See figure 1.) If the engineer did not see or focus enough attention on cues indicating that he needed to slow the train, he would be less likely to realize that accelerating the train to 106 mph was an error at that time and location.
The NTSB has investigated other railroad accidents in which the loss of situational awareness resulted when the engineer was engaged in other operational tasks. In its investigation of the 2002 collision of an Amtrak train and a Maryland Area Regional Commuter (MARC) train in Baltimore, the NTSB determined the engineer lost situational awareness because of excess focus on regulating train speed. Because of her excess focus on regulating the train's speed, she failed to see and comply with both the cab and wayside signals indicating she should stop.[2] Additionally, in the 2003 derailment of a Northeast Illinois Regional Commuter Railroad (Metra) train in Chicago, Illinois, the NTSB determined the engineer had lost situational awareness minutes before the derailment because of his preoccupation with paperwork relating to train operations. Because of his preoccupation, he failed to observe and comply with the signal indications.[3]
- ↑ Mica R. Endsley, "Toward a Theory of Situation Awareness in Dynamic Systems," Human Factors 37, no. 1 (1995): 32-64. In many modes of transportation, this construct is often referred to as "situational awareness."
- ↑ National Transportation Safety Board, Collision of Amtrak Train 9 and MARC Train 437, Baltimore, Maryland, June 17, 2002, Railroad Accident Brief RAB-03/01 (Washington, DC: NTSB, 2003).
- ↑ National Transportation Safety Board, Derailment of Northeast Illinois Regional Commuter Railroad Train 519 in Chicago, Illinois, October 12, 2003, Railroad Accident Report RAR-05/03 (Washington, DC: NTSB, 2003).
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