This is a SEPTA engineer, not the Amtrack guy. But a rock/foreign object thrower on the tracks isn’t going to have the movement range someone on an overpass or pedestrian bridge will have. So that would limit the ability of the guy to roam around the area. Either the trains were all attacked within a few 100 feet along the tracks, or this is irrelevant.
Yet, stupid and as inapplicable as it is, it has diverted someone from the central them of the derailment. ONE HUNDRED MILES PER HOUR>