SCRANTON — Keeping the world’s largest operating steam locomotive, Union Pacific Big Boy 4014, running is no small feat.
A crew of 12 operates and maintains the 1.2-million-pound, 133-foot-long locomotive that was built in 1941, sidelined for decades and restored several years ago for exhibition purposes, said Ed Dickens, Union Pacific’s engineer of the 4014.
Another 20 of Union Pacific’s personnel are on an accompanying train on a cross-country trip to celebrate America’s 250th birthday that brought them to Steamtown National Historic Site for a “Big Boy Reunion” with the park’s nonoperational Big Boy 4012.
The reunion event has already shattered attendance records at Steamtown, with an estimated 30,000 visitors on Monday and another 18,000 on Tuesday. The number might hit 60,000 this weekend.
“By Saturday, we’ll be over 60,000. We’re getting a lot of walk-ins. We might even hit 60,000 today,” Steamtown Superintendent Jeremy Komasz said Friday.
As of Friday morning, 78,000 tickets were sold for the reunion from Monday, June 15, the opening day, through July 1, when the 4014 is expected to depart that morning.
“I think we’ll do 85,000 over the 17 days,” Komasz said.
Dickens, who oversees the Big Boy crew, also oversaw the locomotive’s restoration completed in 2019 and planned the cross-country route for the America250 tour.
Within around two decades, the steam locomotives were replaced by diesels. Around 1961-62, Union Pacific donated Big Boys to various entities, and the 4014 went to an historical organization in California.
Union Pacific reacquired the 4014 in 2015 to restore it to running condition again.
“There was an opportunity to restore one of these, the world’s largest locomotive, something that many people thought was impossible and would never happen again,” Dickens said. “For 30-plus years, prior to that, the number one question our crew would receive when we were out in the field like this was, ‘When are you going to restore a Big Boy?’ and the answer was ‘We’re never going to restore Big Boy.’ That changed and here we are.”
It’s restoration was completed in 2019 for the 150th anniversary of the driving of the golden spike in Ogden, Utah, he said.
The locomotive and what it symbolizes clearly has strongly resonated with the public as millions of spectators have turned out along the cross-country trek to glimpse the rolling piece of American history.
“What it represents to the world is what you see around us (at Steamtown). People are just fascinated with the steam locomotive and the Big Boy represents the largest, the biggest, and there was no other locomotive designed to put this power out at the speed that it runs,” Dicken said. “In the cities where we’ve announced where we’re going to stop, it’s not uncommon to have 10,000 people or more flocking around in a festive rock concert atmosphere, just cheering, holding up signs, little kids holding up little drawings that they’ve made, lots of flag waving and chanting. People are really behind this effort, this locomotive and of course it’s our nation’s 250th birthday and we’re celebrating with this.”
The 4014 has logged about 26,000 miles since being rebuilt.
At the time it was built, “For a steam locomotive design, this was a great machine, the result of many many generations of trial and error and study, and Union Pacific was a leader of the pack when it came to studying and an analyzing all the neat things that they needed to do to always make the locomotives better,” Dickens said. “They were constantly perfecting it, measuring how much water it’s evaporating how much coal it’s burning, how much grease it’s consuming, how long it’s in the shop and what can we do to get it out of the shop and on the rails to earn its keep.”
The 4014 today mostly is the same as it was in the 1940s. The crew members are cross-trained such that they each can perform any of the various duties, including engineer, fireman and maintenance.
“Yes, it’s an old locomotive. Yes, it’s old technology, it’s not efficient like our modern locomotives are, but look at the greatness of what this is,” Dickens said. “Union Pacific took 2.5 years to disassemble it and build this beautiful unique machine you see here, and here it is right next to one of its brothers, the 4012, downtown at the National Historic Site in Scranton, Pennsylvania.”
Dickens likened the locomotive to a water heater in a home, which is a vertical cylinder tank with pipes and a heating element, usually either electric or gas. The steam locomotive similarly has pressure vessel, but much larger and mounted horizontally with a giant fire box on one end that burns fuel to produce steam.
“It’s the same principle,” as a water heater, he said.
The 4014 was converted from coal to oil, and it runs on used motor oil, the same kind of batch oil an asphalt plant uses, he said.
Steam moves large, heavy-duty pistons that propel the massive driving wheels. The engineer drives the vehicle via a hand throttle.
“It’s all 100% 1940s. It’s all by touch, seat-of-the-pants. It’s a beautiful art to operate and fire this locomotive. There’s a unique skill set that you develop, a lot of nuance,” Dickens said.
The frame is cast as one massive, rugged unit and the wheel assemblies are similarly large and heavy-duty.
“These are very specific, they have a unique look to them,” Dickens said of the Big Boys. “When you’re into the history of steam locomotives, you can see the Union Pacific look, certain little details about them. They were just so darn well designed.”
This was the locomotive technology America had until 1959, when supplanted by diesels, he said.
The 4014 takes a week to cool down and the crew will soon start doing maintenance.
“We’ll see a flurry of activity. We’ll take things apart, we’re going to get inside of it and do lots of cleaning,” Dickens said.
They will fire up the 4014 a few days before departure, to get it back up to running temperature.
Union Pacific engineer Ed Dickens poses for a photograph with the Big Boy 4014 steam locomotive at the Steamtown National Historic Site in Scranton Friday, June 19, 2026. (SEAN MCKEAG / STAFF PHOTOGRAPHER)
Union Pacific train engineer Ed Dickens in the cab of Big Boy 4014, the world’s largest operating steam locomotive, waves to visitors at Steamtown National Historic Site in Scranton on Friday, June 19, 2026. The 4014 is on a cross-country America250 tour and stopped in Scranton for a two-week stay for the Big Boy Reunion with Steamtown’s non-operational Big Boy 4012. (JIM LOCKWOOD / STAFF PHOTO)
Union Pacific engineer Ed Dickens poses for a photograph with rail fans near the Big Boy 4014 steam locomotive at the Steamtown National Historic Site in Scranton Friday, June 19, 2026. (SEAN MCKEAG / STAFF PHOTOGRAPHER)
Engineer of Union Pacific’s Big Boy 4014 Ed Dickens poses for a photograph with the steam locomotive parked at the Steamtown National Historic Site in Scranton Friday, June 19, 2026. (SEAN MCKEAG / STAFF PHOTOGRAPHER)
Massive driving wheels of Union Pacific’s Big Boy 4014, the world’s largest operating steam locomotive, during a visit to Steamtown National Historic Site in Scranton on Friday, June 19, 2026. The 4014 is on a cross-country America250 tour and stopped in Scranton for a two-week stay for the Big Boy Reunion with Steamtown’s non-operational Big Boy 4012. (JIM LOCKWOOD / STAFF PHOTO)
Union Pacific train engineer Ed Dickens climbs a ladder into the cab of Big Boy 4014, the world’s largest operating steam locomotive, at Steamtown National Historic Site in Scranton on Friday, June 19, 2026. The 4014 is on a cross-country America250 tour and stopped in Scranton for a two-week stay for the Big Boy Reunion with Steamtown’s non-operational Big Boy 4012. (JIM LOCKWOOD / STAFF PHOTO)
Union Pacific engineer Ed Dickens poses for a photograph in the Big Boy 4014 steam locomotive at the Steamtown National Historic Site in Scranton Friday, June 19, 2026. (SEAN MCKEAG / STAFF PHOTOGRAPHER)
A Union Pacific logo on the floor below an open door to the fire box inside the cab of Union Pacific’s Big Boy 4014, the world’s largest operating steam locomotive, at Steamtown National Historic Site in Scranton on Friday, June 19, 2026. The 4014 is on a cross-country America250 tour and stopped in Scranton for a two-week stay for the Big Boy Reunion with Steamtown’s non-operational Big Boy 4012. (JIM LOCKWOOD / STAFF PHOTO)
Union Pacific train engineer Ed Dickens in the driver’s seat in the cab of Big Boy 4014, the world’s largest operating steam locomotive, at Steamtown National Historic Site in Scranton on Friday, June 19, 2026. The 4014 is on a cross-country America250 tour and stopped in Scranton for a two-week stay for the Big Boy Reunion with Steamtown’s non-operational Big Boy 4012. (JIM LOCKWOOD / STAFF PHOTO)
Some of the controls inside the cab of Union Pacific’s Big Boy 4014, the world’s largest operating steam locomotive, at Steamtown National Historic Site in Scranton on Friday, June 19, 2026. The 4014 is on a cross-country America250 tour and stopped in Scranton for a two-week stay for the Big Boy Reunion with Steamtown’s non-operational Big Boy 4012. (JIM LOCKWOOD / STAFF PHOTO)
Union Pacific’s Big Boy 4014, the world’s largest operating steam locomotive, during a visit to Steamtown National Historic Site in Scranton on Friday, June 19, 2026. The 4014 is on a cross-country America250 tour and stopped in Scranton for a two-week stay for the Big Boy Reunion with Steamtown’s non-operational Big Boy 4012. (JIM LOCKWOOD / STAFF PHOTO)
A plaque with historical information on the exterior of Union Pacific’s Big Boy 4014, the world’s largest operating steam locomotive, at Steamtown National Historic Site in Scranton on Friday, June 19, 2026. The 4014 is on a cross-country America250 tour and stopped in Scranton for a two-week stay for the Big Boy Reunion with Steamtown’s non-operational Big Boy 4012. (JIM LOCKWOOD / STAFF PHOTO)
A view from inside the cab of Union Pacific’s Big Boy 4014, the world’s largest operating steam locomotive, of the nonoperational Big Boy 4012 at Steamtown National Historic Site in Scranton on Friday, June 19, 2026. The 4014 is on a cross-country America250 tour and stopped in Scranton for a two-week stay for the Big Boy Reunion with Big Boy 4012. (JIM LOCKWOOD / STAFF PHOTO)
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Union Pacific engineer Ed Dickens poses for a photograph with the Big Boy 4014 steam locomotive at the Steamtown National Historic Site in Scranton Friday, June 19, 2026. (SEAN MCKEAG / STAFF PHOTOGRAPHER)