CHEYENNE, Wyo. - In its prime, a massive steam locomotive known as Big Boy No. 4014 was a moving eruption of smoke and vapor, a 6,300-horsepower brute dragging heavy freight trains over the mountains of Wyoming and Utah.
It's been silent for half a century, pushed aside by more efficient diesels, but now it's coming back to life. The Union Pacific Railroad is embarking on a yearslong restoration project that will put No. 4014 back to work pulling special excursion trains.
"It's sort of like going and finding the Titanic or something that's just very elusive, nothing that we ever thought would happen," said Jim Wrinn, editor of Trains, a magazine that covers the railroad industry.
"Something that's so large and powerful and magnificent, we didn't think any of them would ever come back," he said.
The American Locomotive Co. in Schenectady, N.Y., built 25 of the monsters to Union Pacific's specifications between 1941 and 1944, and they became legendary. They were the largest steam locomotives ever to work the rugged terrain of the American West, and by most standards the largest anywhere in the world, said Gordon McCulloh, a meticulous historian of Union Pacific steam power.
Even the name is legendary. An unknown worker scrawled "Big Boy" on the front of one of the engines when it was under construction.
"It came out one day, and it had 'Big Boy' in chalk on it. And from that day forward, it was Big Boy," said Ed Dickens Jr., Union Pacific's senior manager of heritage operations, who will oversee the restoration at the railroad's steam shop in Cheyenne, Wyo.
Dickens and his crew re-created the chalk inscription on No. 4014 when they began to move it.
Big Boys are 132 feet long, including the tender, which carried coal and water. They weigh 1.2 million pounds with a full load of fuel. They are essentially two engines under one boiler, with two sets of eight drive wheels, each set powered by two enormous cylinders nearly 2 feet across.
And they were engineered to reach 80 mph, even though the railroad never intended to run them that fast. The point was to fine-tune the locomotives so they stayed in balance at any speed and didn't beat themselves up with their own powerful forces.
Their enormous bulk also hid some slick engineering, including a suspension system that kept the drive wheels pressed against the rails when the locomotive straddled hills or valleys.
Eight Big Boys are on display around the country. Union Pacific chose the 4014 for restoration because it spent more than 50 years in the friendly Southern California climate.
No. 4014 will be towed across Nevada, Utah and Wyoming to Cheyenne, arriving May 8.