Union Pacific 4014 To Head East For The First Time

Published: March 20, 2025

Perhaps the most significant aspect of Union Pacific's America250 announcement is the confirmation that Big Boy No. 4014—the world’s largest operating steam locomotive—will tour the eastern United States for the first time in preservation history.

Complete details of the trip have not yet been released but the locomotive is scheduled to travel to Philadelphia for the Fourth of July, symbolically linking the railroad’s history with the birthplace of American independence.

Planned stops along the route will also include communities in:

Illinois
Indiana
Ohio
New York
Pennsylvania

This eastern leg follows the already-announced western portion of the tour, which begins March 29, 2026, from Cheyenne, Wyoming, and celebrates the role railroads played in building and unifying the nation.

A Union Pacific publicity photo of 4014 in the May of 2019.

About 4014

Union Pacific 4-8-8-4 “Big Boy” No. 4014 stands as the largest and most powerful operating steam locomotive in the world, and one of the most iconic symbols of American railroading. Built in 1941 by the American Locomotive Company (ALCO) in Schenectady, New York, No. 4014 was part of a fleet of 25 massive articulated locomotives designed to conquer the steep grades of the Wasatch Mountains between Ogden, Utah, and Green River, Wyoming.

The Big Boys were engineered during a period when Union Pacific required immense power to move heavy wartime freight efficiently. Their 4-8-8-4 wheel arrangement—featuring two sets of eight driving wheels under a single boiler—allowed them to generate extraordinary tractive effort while maintaining flexibility on curves. Unlike earlier articulated designs, the Big Boys were “simple articulateds,” meaning steam was fed directly to all cylinders, improving both efficiency and performance at speed.

No. 4014 spent its revenue career hauling long freights across the western United States until it was retired in 1961, after accumulating more than one million miles in service. It was subsequently donated to the RailGiants Train Museum in Pomona, California, where it remained on static display for over five decades.

In 2013, Union Pacific reacquired the locomotive as part of its historic steam program. After an extensive, multi-year restoration at the railroad’s steam shop in Cheyenne, Wyoming, No. 4014 returned to operation in May 2019—becoming the only operational Big Boy in existence. The restoration included converting the locomotive to burn No. 5 fuel oil instead of coal, along with modern upgrades to ensure safe operation on today’s rail network.

Since its return, No. 4014 has toured thousands of miles across the Union Pacific system, drawing massive crowds and serving as a moving ambassador for railroad history. Its appearances at major events—including the 150th anniversary of the Transcontinental Railroad—have cemented its role as a centerpiece of modern rail preservation.

Technically, the Big Boy remains a marvel of engineering. Weighing over 1.2 million pounds with its tender, the locomotive can produce more than 6,000 horsepower and generate over 135,000 pounds of tractive effort. Despite its immense size, it was capable of sustained speeds of 60 mph, making it equally suited for both heavy freight and fast mainline service.

Today, Union Pacific 4014 represents not only the pinnacle of steam locomotive design but also the enduring legacy of American industrial innovation. As it continues to operate in excursion service—now including planned appearances during the nation’s America250 celebration—it offers a rare, living connection to the golden age of steam railroading.

4014 Specifications

Specification	Details
Builder	American Locomotive Company (ALCO)
Build Date	November 1941
Wheel Arrangement	4-8-8-4 (Simple Articulated)
Driver Diameter	68 inches
Boiler Pressure	300 psi
Cylinders	Four (23.75" x 32")
Tractive Effort	135,375 lbs
Horsepower	Approx. 6,290 hp
Locomotive Weight	762,000 lbs
Total Weight (with Tender)	1,208,000 lbs
Fuel Type	No. 5 Fuel Oil (converted from coal)
Fuel Capacity	Approx. 6,200 gallons
Water Capacity	25,000 gallons
Length	132 feet 9 inches
Top Speed	~60 mph
Retired	1961
Restored	2019 (Union Pacific Steam Program)

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Union Pacific 4014 To Head East For The First Time

About 4014

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4014 Specifications