. >> reporter: zach snyder is one of the three who lost their lives.is wife somehow survived also killed in the crash two passengers dozens were injured. five hospitalized. with the ntsb piecing together saturday's crash, amtrak's empire builder was traveling west with two locomotives and ten cars on a fairly straight stretch of tracks. at least five cars suddenly derailed three plowing off the tracks entirely near joplin with more than 150 onboard, the train was equipped with positive train control, a safety feature that virtually prevents all derailments from human air. >> we'll be looking at the mechanical condition of the train. we will be looking at the human factors of the crew. we will be looking at the people who inspected the track. we will be looking at the track conditions. >> reporter: bnsf, who maintains the track, says the rail had just been inspected days earlier. tonight the widening probe for answers after a tragedy on the tracks >> and, miguel, we know from previous accidents that some of these trains are equipped with recorders, incl