During World War II Union Pacific operated some of the most modern and powerful steam locomotives ever built. Among them were the famous "Big Boys," the largest steam locomotives in the world. Working with them were the "800-class" high-speed passenger locomotives, as well as hundreds of older class steam engines. Union Pacific's steam legacy continues today with the preservation and operation of its historic fleet – No. 844 and No. 4014.


Thanks for coming out to see Big Boy No. 4014 in Denver!


Where is the Big Boy right now?


Steam Club members get the latest news and scheduling information about Union Pacific's legendary steam train program!

Find out more

Union Pacific Steam Shop Tour

Bringing the Big Boy Back to Life

Trace the progress of Union Pacific and Central Pacific railroads as they raced to complete the transcontinental railroad and discover the communities they created along the way.

Explore the Great Race website