Nurse Angie Boivin had just tended to a woman whose leg was severed when she saw her husband Larry lying nearby. She says that she was with him when he took his last breath.

Larry Boivin earned a Purple Heart in Iraq, but he didn't survive a Union Pacific freight train that slammed into the trailer he and other veterans were riding during a 2012 parade in Texas. Four veterans died and more than a dozen people were injured.

Angie Boivin and 42 others sued Union Pacific for negligence, saying it knew 10 months before the collision of a defect in track circuitry and didn't fix it. They also allege the railroad reduced the warning time in violation of a state agreement.

Union Pacific says it is not at fault.