Copyright © 1995-2001 Denver Public Library, Colorado Historical Society, and Denver Art Museum
Build Date: December, 1941
Builder: ALCO, Schenectady, NY
Current Status: Static
Road: Union Pacific
Configuration: 4-8-8-4
Union Pacific's route across the Wahsatch mountains in southwest Wyoming and northern Utah, part of the original transcontinental railroad, provided a significant obstacle to moving freight. As steam locomotive technology progressed, Union Pacific ordered larger, faster and more powerful locomotives: 2-8-8-0s in 1918, the three-cylinder 4-12-2s in 1926, then 4-6-6-4s in 1937, and ultimately a locomotive which could move freight over steep Sherman Hill unassisted and maintain a fast schedule. In 1941, Union Pacific received the first out of an eventual 25 locomotives in the 4000 class dubbed "big boys," the last five of which were delivered in 1944. At the time, these were the longest and among the heaviest, most powerful steam locomotives in the world.
Big Boy 4018 was in service and assigned to Wyoming's Cheyenne-Green River territory in September of 1957, having received its final repairs at the Cheyenne shops in April of 1957. By October of 1957 engine 4018 was stored serviceable at Green River. 1958 saw several 4000s in service on the Cheyenne-Laramie segment only. As a result some 4000s were stored at Laramie at the end of 1958, and the last six 4000s located at Cheyenne were placed into service for just 15 days in 1959. Union Pacific 4018 was officially retired in 1962 and donated in 1964, traveling from Wyoming to Kansas City, then south via the Santa Fe into Dallas. In 1998 the museum was approached with a proposal to restore 4018 to operation for a feature film which did not materialize. Union Pacific 4018 remains on static display at the museum site in Dallas as it has been since 1964. There are no plans for an operational restoration.