Union Pacific’s Big Boy 4014 prepares for coast-to-coast tour

Union Pacific lined up Big Boy No. 4014 for a coast-to-coast tour in 2026, putting the East Coast on the route for the first time as part of America’s 250th anniversary commemorations. The locomotive, described by Union Pacific as the world’s only operational Big Boy and the world’s largest operating steam engine, had already returned to service in 2019 after a multi-year restoration that brought it back to the rails as a moving piece of railroad history.

No. 4014 was delivered in December 1941 to support the war effort, when Union Pacific was operating some of the most powerful steam locomotives ever built. Twenty-five Big Boys were built exclusively for the railroad, and the class was designed with articulated, hinged frames so the 132-foot locomotives could handle curves while hauling heavy equipment between Ogden, Utah, and Cheyenne, Wyoming. Union Pacific says the engines weighed 1.2 million pounds, a scale that helped make them famous far beyond the railroad corridor they once served.

The revival of No. 4014 sits alongside another survivor from the same era, steam locomotive No. 844. Delivered in 1944, Union Pacific says No. 844 was never retired from service and remains the last steam locomotive built for the railroad. Together, the two engines anchor the company’s historic steam program, which Union Pacific says is meant to connect people with history and innovation.

That appeal reaches beyond one railroad. The Smithsonian Institution’s collections place steam locomotives at the center of American transportation history, noting that steam dominated U.S. passenger rail travel from about 1910 to 1955. Among the preserved machines are John Bull, built in 1831, and Southern Railway 1401, reminders that the public still gathers around iron, motion and machinery that were once ordinary and are now rare. In an era built on screens and speed, Union Pacific’s steam fleet keeps drawing crowds to bridges, curves and station platforms where the past still moves under its own power.