Accident Report Detail

On July 31, 1979, at 10:30 p.m., eastbound Union Pacific (UPRR) freight train No. GRX 31 derailed at Granite, Wyoming. The train was moving on main track No. 2 at 75 mph when the second and third locomotive units derailed and overturned in a 305.8' curve, separated from the lead unit, destroyed the track, and caused the following 81 freight cars to derail. Two locomotive units were heavily damaged, 80 freight cars were destroyed and 2 overpass bridges of Interstate 80 were damaged extensively. Total damage was estimated at $5 million.

The National Transportation Safety Board determines that the probable cause of this accident was the loss of braking capability because of a closed angle cock in the train line, which resulted in the engineer's inability to control the speed of the train, and the failure of the conductor in the caboose to apply the train brakes in emergency when the speed became excessive.