Burlington Northern freight train, Extra 5701 East, with 69 cars and three locomotive units approached Sheridan Yard, Wyoming, about 1:20 a.m., March 28, 1971. A yard clerk used a radio to advise the crew to remain on the main track, stop the train, and deliver the locomotive to the roundhouse. Unknown to the yard clerk and the crew of Extra 5701 East, a draft of cars was standing on the main track short of the spot where the train was to stop. Visibility was decreased by blowing snow and when the standing cars unexpectedly came into view, the train could not stop before it struck them. The fireman who was operating the locomotive, and the engineer, were killed. The locomotive, the first three cars, and cars 22 through 26 of Extra 5701 East, and the first three standing cars were derailed.