Article Photos: Train engineer's vision problems led to deadly Oklahoma wreck, NTSB rules 1/3

FILE - In this June 24, 2012, file photo smoke rises from two cargo trains that collided near Goodwell, Okla. The National Transportation Safety Board said Monday, July 9, 2012, the trains weren't speeding at the time of the wreck. Three Union Pacific employees died in the accident. Another worker jumped to safety. (AP Photo/The Guymon Daily Herald, Trudy Hart, File)