On July 31, 2012, at 2:25 a.m., a Union Pacific Railroad (UPRR) switchman was killed after being crushed between two rail cars in the Mason City, Iowa, rail yard. The switchman was assigned to yard job YMC04. He went on duty on July 30, 2012, at 10:30 p.m., along with an engineer and a footboard yardmaster. During switching operations, the switchman discovered a coupler knuckle with a missing pin. While making repairs to the coupler knuckle, he was struck and fatally injured by two rail cars that rolled into him.