Despite having such poor vision that he drove with a restricted (auto) license, a train engineer was medically recertified by his employer, Union Pacific Railroad. Those vision problems contributed to fatal 2012 head-on collision between two freight trains in Oklahoma, according to the National Transportation Safety Board (NTSB).
The June 24 accident killed the engineer and conductor of the eastbound trains and the engineer of the westbound train. The conductor of the westbound train was able to jump to safety.