About 1:15 am on June 15, 1987, Southern Pacific Transportation Company (SP) freight train Extra 7791 West collided head-on with SP freight train Extra 7267 East near Yuma, Arizona. The yardmaster had instructed Extra 7791 West to proceed westward on the westbound main track the subway, stop, wait for an eastbound train to pass, cross over to the westbound main track, and proceed to the yard office. Meanwhile, the yardmaster had planned for Extra 7267 East to depart the yard office and proceed eastward on the eastbound main track to the subway, stop to align the crossover switches, and proceed eastward on the eastbound main track. However, Extra 7267 crossed over to the westbound main track at the subway, and the trains collided head-on. THE engineer of Extra 7267 East was killed.