This case really involves, unfortunately involves a railroad employee who received fatal injuries as a result of being run over by rail equipment. In this particular case, what these individuals are doing is they're working in a classification yard. They are in the process of grabbing cars and putting them into these different tracks so that eventually another locomotive will come in and grab those cars and take them somewhere else. For this particular case, we wanted to understand what was the crew doing the moments before an individual received an injury.
Very quick into the case, it became an issue of lighting. The specific conditions were unique in that the tracks were close together and parallel so that once you put cars along the tracks, you create shadows. So we needed to determine whether or not adding additional light fixtures would actually create a better lighting condition.
First thing that you need to do with any type of railroad investigation that involves switching operations is understanding what the movements of the train are. So a movement is defined as simply the motion of the train itself. A move could be one foot or it could be a mile, and it's literally as it begins to move until it stops that is defined as one movement of the train. For this particular incident, there were 12 specific moves prior to the incident. Once we backed out what the movements of the train were, we were able to determine where cars had been left on the track prior to them coming back in for the final move. And that's important because it establishes the location of the specific car that caused the injuries in relation to the location of where we had specific evidence.
Nighttime visibility and conspicuity analysis are tools that allow the human factors expert to the best indication of what the scene looked like. So we try to replicate the scene as best we can. In this case, we had moved the train cars to a position where we best thought they represented the scene. The individual who did fall did have a head lamp, and so I was asked to evaluate, could a lantern illuminate enough? Could a headlight illuminate enough such that an employee could walk reasonably safely through the yard?
We received a headlamp that was identical to the individual, and we had a camera, and we actually mounted the lantern headlight right above the camera so that wherever we pointed the camera, the headlight was able to shine as if it were on somebody's head. Given the fact that our individual who fell was a frequent user of this location, knew how to walk along this type of surface, had a supplemental light source that he could direct in any location that he wanted, had he used the light source, relied on his own experience to gauge his travel through this area, there would've been sufficient lighting for him to safely accomplish the task he was doing that day.
We have lots of tools to our disposal. One of the things we have is a motion capture suit. It's called a mocap suit. And so we had actually set up some experiments so that we could understand the timing, and it gave us accurate representation of the gate itself, which we were able to put into the program so that it was biofidelic or it looked very accurate, to essentially demonstrate the fundamental laws of physics where we developed animations to show how people walk, essentially looking at gait. If you had tripped, how you would move? To demonstrate that it just wasn't possible to trip and then subsequently move 40 inches or more to the position that they were alleging that he had stumbled or tripped to.
We have done some extensive research to understand how injuries occur when you're run over by rail equipment, specifically looking at the fracture pattern of bones when run over. This individual had only one leg amputated and the other leg wasn't. In a trip and fall scenario, if you trip and stumble in one direction towards a rail, for example, you're going to fall over the rail such that either your entire body will be essentially run over, perhaps mid-torso, or both legs would be involved in that particular scenario. So we were able to rule out the scenario of him tripping and falling over the rail.