Big Boy, the largest operating steam locomotive in the world, roared through Truckee late last Sunday. It was delayed two and a half hours because it hit a fallen tree on the tracks near Auburn. Because it was delayed, the stop at Truckee was canceled. Still the crowd was able to watch it come past the station.
Prior to the train’s arrival, our Nevada County Supervisor – Hardy Bullock gave a talk on the importance of railroads to Truckee and Truckee Vice Mayor – Jan Zabriskie talked about the Big Boy locomotive and how the railroad changed Truckee’s industries.

Dan Cobb and other model railroad builders set up a display of 1927 downtown Truckee. Engel & Volkers realtors lent their office space to the Truckee Donner Railroad Society for the exhibit. The historical model is a work in progress but we hope to have a permanent display soon.

Also, attendees were able to visit the nearby Truckee Railroad Museum and the Museum of Truckee History to learn more about Truckee’s history with the railroad.

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Big Boy’s visit was the first time this big locomotive was in Truckee. When it was first used by the Union Pacific, Southern Pacific ran the railroad through Truckee and they didn’t want it. The problem was locomotives, with the engineer’s cab at the rear, choked the engineers when they went through the two-mile-long tunnel 41 on Donner Summit. Southern Pacific had been using cab forward locomotives for many decades to solve this problem.

The Union Pacific Big Boy locomotives are among the most iconic and powerful steam engines ever built. These machines represent the pinnacle of steam locomotive design and engineering, symbolizing the era of steam’s dominance in the mid-20th century.

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Just behind the engine was a black tender that holds fuel oil and some water. Behind that were two yellow tenders that hold water. In the days of steam engines, all towns including Truckee had large water tanks to replenish the water that had turned to steam. Today, almost all those water towers have been torn down and extra tenders of water are needed to keep the locomotive running.

You may have also noticed a diesel engine behind the Big Boy. This historic diesel painted with the colors of the old Western Pacific serves many purposes. Its power provides a boost that saves on No. 4014 fuel stops. It’s a much-preferred power source in tunnels and if Big Boy were disabled on the main line, the diesel could still move the train.

A number of historic passenger cars painted Union Pacific yellow made up the rest of the train.

Historical Background

In the early 1940s, the Union Pacific Railroad sought to develop a new class of locomotives that could haul heavy freight trains over the rugged terrain of the Wasatch Mountains between Ogden, Utah, and Green River, Wyoming. At Ogden, the Southern Pacific took over the trains and hooked their cab forwards to them.

When the Big Boy was first used by the Union Pacific, Southern Pacific (SP) owned and ran the railroad through Truckee. SP didn’t want the cab-in-back locomotive. Smoke from the engine choked the engineers when they went through the tunnels on Donner Summit. SP had solved this problem using cab-forward locomotives.

Union Pacific’s goal with the Big Boy was to create a locomotive capable of pulling long freight trains over the Rockies without the need for multiple engines, thereby increasing efficiency and reducing operational costs.

Union Pacific worked closely with the American Locomotive Company (ALCO) to design and build these massive locomotives. Originally the locomotives were to be called Wasatch but a builder chalked the name Big Boy on the side. The name stuck. These locomotives were a series of 25 articulated 4-8-8-4 steam locomotives, produced between 1941 and 1944. The first of these locomotives, numbered 4000, rolled out of the ALCO plant in Schenectady, New York, in September 1941.

Big Boy 4014 was retired in 1961 and given to the RailGiants Museum in Pomona, California. In 2013 the Union Pacific made preparations to haul the static Big Boy from the Pomona Fairgrounds back to Cheyene Wyoming for a full restoration.

Technical Aspects

1. Design and Configuration: The Big Boy locomotives are of the 4-8-8-4 wheel arrangement, meaning they have four leading wheels on two axles that turn as the locomotive turns, two sets of eight driving wheels on four axles each on a rigid base, and four trailing wheels on two axles. This configuration is known as an articulated locomotive design, allowing the engine to navigate tighter curves by having two sets of driving wheels connected by a pivot point.
2. Dimensions and Weight: Big Boys are among the largest steam locomotives ever built. Each engine measures approximately 132 feet long, including the tender. They stand over 16 feet tall and weigh about 1.2 million pounds (600 tons) when fully loaded with coal and water. The massive weight is distributed over the locomotive’s numerous wheels, reducing the pressure on the tracks.
3. Power and Performance: Each Big Boy locomotive was designed to generate enormous power. With a boiler pressure of 300 psi and a tractive effort of 135,375 pounds-force, these engines could produce over 6,000 horsepower. This immense power enabled them to haul freight trains weighing up to 3,600 tons (50 loaded freight cars) over steep grades and long distances without assistance.
4. Boiler and Firebox: The boiler of a Big Boy is a marvel of engineering, featuring a large firebox to burn coal efficiently and produce the high-pressure steam needed to drive the pistons. The firebox is approximately 23 feet long and 96 inches wide, with a grate area of 150 square feet. The boiler’s water capacity is around 25,000 gallons, and the tender holds 28 tons of coal. The locomotive was converted to burn oil in 2019.
5. Innovations: The Big Boy locomotives incorporated several innovative features for their time. They were equipped with a dual air pump system for the brakes, ensuring reliable stopping power. Additionally, they had a stoker to mechanically feed coal into the firebox, reducing the labor-intensive work of the fireman.

Operational History

The Big Boys served the Union Pacific Railroad with distinction, primarily hauling freight across the mountainous regions of the western United States. Their reliability and power made them invaluable during World War II when the demand for efficient transportation of war materials was at its peak.

Despite their success, the advent of diesel-electric locomotives in the 1950s marked the beginning of the end for steam engines. Diesel engines offered greater efficiency, lower maintenance costs, and longer operational ranges without the need for water and fuel stops. By 1959, the Big Boys were retired from active service, replaced by more modern diesel-electric locomotives.

Preservation and Legacy

Of the 25 Big Boy locomotives built, eight have been preserved and are on display at various museums and heritage railways across the United States. One of the most notable examples is Union Pacific 4014, which was restored to operating condition in 2019 by Union Pacific’s heritage operations team. This restoration project brought a Big Boy back to life, allowing enthusiasts and the general public to experience the power and grandeur of these legendary locomotives firsthand.

The Big Boy locomotives remain a testament to the ingenuity and ambition of American railroading during the steam era. Their impressive size, power, and engineering continue to captivate the imagination of rail enthusiasts and historians alike.

Thanks to Jen Callaway – Truckee’s Town Manager and Peggy Ygbuhay – Union Pacific’s Senior Director of Public Relations for all their work helping us to make this a fun event.

About the author
Jerry Blackwill is currently President of the Truckee Donner Railroad Society and the Museum of Truckee History.