Celebrate with shop.trains.com as the 80-Year-Old Steam Locomotive continues its tour across the US.
Union Pacific’s Big Boy No. 4014 and its 2026 coast-to-coast tour has been a spectacle, with the 1.2 million pounds of rolling steel, the thundering exhaust, and the crowds lining the tracks. But behind the scenes, getting the world’s largest operating steam locomotive onto unfamiliar eastern railroads involves a collision of old-world engineering and modern-day regulation.
The story of how that was possible starts with a single piece of paper filed with the Federal Railroad Administration in February 2026.
As Big Boy 4014 continues its first-ever coast-to-coast tour in 2026, we here at shop.trains.com are celebrating this once-in-a-lifetime opportunity to witness the engineering marvel in motion.
The Cab Signal Problem
As Big Boy’s western leg wrapped up in late April after 27 whistle-stops across Wyoming, Utah, Nevada, and California, Union Pacific was already working to solve a puzzle that most railfans didn’t know existed. The eastern leg of the tour, scheduled to begin May 25 and run through July 29, will carry No. 4014 onto Norfolk Southern trackage for the first time, traversing the Fort Wayne, Cleveland, Pittsburgh, and Harrisburg lines. That routing takes the Big Boy over the former Pennsylvania Railroad main line, including the legendary Horseshoe Curve. That’s territory that No. 4014 has never seen since rolling out of the ALCO plant in Schenectady, New York, in December 1941.
Much of NS’s eastern territory is equipped with cab signal systems, and federal regulation 49 CFR 236.566 requires any locomotive operating in that territory to carry compatible onboard equipment. Big Boy doesn’t have it, and the reason it doesn’t is because Union Pacific already upgraded the locomotive with a newer technology.
In 2021, No. 4014 became the first mainline steam locomotive in history to be equipped with Positive Train Control, the safety system mandated by Congress following the 2008 Chatsworth Metrolink crash. That initial installation was a creative workaround. The PTC onboard computer lived in a trailing diesel locomotive, SD70M No. 4015, and was hard-wired to a display unit in the Big Boy’s cab. It worked, but it tethered the steam locomotive to a diesel at all times.
Then in May 2024, Union Pacific installed PTC equipment directly in a cabinet in the tender and added a third dynamo for electrical power. For the first time, Big Boy could operate on the mainline entirely under its own power. Heritage Operations Manager Ed Dickens called the upgrade a simplification that made trip planning easier and eliminated the need to physically move hard-wire connections every time the locomotive was uncoupled.
The irony is that that upgrade removed the cab signal equipment that had been part of the earlier system. PTC handles the safety functions that cab signals historically provided, such as speed enforcement, signal compliance, and authority verification, but it does so through a different technological architecture. On Union Pacific’s western territory, where PTC is the governing system, that’s not a problem. On Norfolk Southern’s cab-signal-equipped eastern lines, it is.
In February 2026, both UP and NS filed petitions with the FRA seeking a waiver from the cab signal requirement. NS proposed alternative safety measures, including reduced operating speeds, pilot engineers familiar with the territory, and supplemental signaling protocols. The FRA opened a public comment period through April 3 under docket number FRA-2026-0497.
It’s a fascinating regulatory moment. Installing cab signal equipment on a steam locomotive built in 1941 would be, in the petition’s framing, impractical. You can’t easily graft mid-century signal technology onto a machine that predates it, especially one already modified to carry a 21st-century PTC system. The Big Boy’s cab is a working artifact. Every modification has consequences for the integrity of the original machinery.
The Coal to Oil Conversion
This tension between preservation and modernization isn’t new for No. 4014. It has been present since the locomotive’s restoration.
When Union Pacific reacquired No. 4014 from the RailGiants Train Museum in Pomona, California, in 2013 and began its multi-year restoration, the Steam Team under Ed Dickens made one major alteration to the locomotive’s original configuration: they converted it from coal to No. 5 fuel oil.
The conversion involved replacing the firebox grates with a fire pan and an oil burner, which fundamentally changed how the locomotive creates steam. It was only the second time a Big Boy had undergone a coal-to-oil conversion (No. 4005 ran briefly on oil from 1946 to 1948 before being converted back to coal due to uneven heating in its large, single-burner firebox).
Coal firing on a modern railroad network would present significant logistical and safety challenges. Oil is cleaner, easier to handle, and, as Dickens pointed out during the western leg, far less likely to start a wildfire. That’s not an academic concern when you’re running a locomotive that generates a visible fireball inside its combustion chamber through drought-prone western states.
The oil conversion also simplified the support infrastructure. The Steam Team designed a ground-level fueling system that eliminates the need to climb atop the massive tender, and engineered an external oil-fill system for lubrication comparable to servicing a modern diesel. These modifications reduce risk and speed up servicing without fundamentally altering what the Big Boy is.
The Steam Team has to balance modern regulatory and operational environments while preserving the essential character of a machine that was state-of-the-art during the last world war.
Fitting on Eastern Rails
Then there’s the question that sounds almost comical until you think about it: can the Big Boy physically fit through eastern tunnels and under eastern bridges?
When ALCO designed the Big Boy class in the early 1940s, they pushed every dimensional limit available. At 133 feet long, 11 feet wide, and 16 feet tall, the locomotive was built to the absolute maximum envelope that contemporary western infrastructure would allow. Any wider and it wouldn’t clear certain passages. Any taller, and tunnels became a problem. Any longer, and curves would be unnavigable, even with the locomotive’s articulated frame.
The Big Boy was built specifically for Union Pacific’s western network. It has never operated on eastern rails. In early 2026, Ed Dickens posted photos on UP’s official Steam Shop Club Facebook page showing team members taking physical measurements between tracks and adjacent structures along the proposed eastern route. No amount of paperwork can replace hands-on clearance verification.
Operating a locomotive this size on unfamiliar trackage means verifying clearances at every bridge, tunnel, yard, and platform along the route, as well as coordinating with Norfolk Southern’s dispatchers to thread a 1.2-million-pound steam locomotive through active freight corridors. All of this for a machine that requires a five-person crew staying aboard overnight, relighting the firebox each morning in a process that takes several hours, and stopping periodically so maintenance crews can oil the running gear by hand.
Thankfully, after due diligence and months of survey work, Dickens responded to concerns by stating simply that the locomotive would fit with room to spare.
What makes the Big Boy’s 2026 tour remarkable is that every mile of eastern trackage takes compromises between preserving the authentic machinery of a locomotive that traveled over a million miles in revenue service and complying with safety systems that didn't exist when it was retired in 1961.
The cab signal waiver, the coal-to-oil conversion, the PTC installation, and the clearance surveys are what separates a museum piece from a living, operating machine.
When the eastern leg launches on May 25, Big Boy will traverse territory it hasn’t seen in over 84 years, heading through Omaha, Kansas City, St. Louis, Chicago, and onward to Buffalo, Scranton, and Philadelphia for the Fourth of July. Every mile exists because a small team of engineers, regulators, and railroaders figured out how to make the old and the new work together.
Looking for Big Boy merchandise to commemorate the 2026 Coast-to-Coast Tour? Browse the full collection at shop.trains.com.
Celebrate the Big Boy with Exclusive Merchandise
If you want to commemorate this historic tour with some merch, shop.trains.com has an impressive collection of Big Boy No. 4014 gear. Bring a piece of railroading history home, or bring it with you if you plan to attend any of the tour stops!
Union Pacific 4014 Spot Plate Pin, Big Boy 4014 Locomotive Pin, and Builder’s Plate Pin
These pins were designed to celebrate No. 4014’s restoration in 2019. They feature raised lettering, rubber backing for secure placement/wear, and silver hard enamel. Add them to your jacket, hat, bag or train memorabilia to give them some flair and start conversations.
Big Boy Chalk Writing Mug and Tee
These memorabilia items were designed exclusively for Trains magazine to celebrate the restoration and touring of Big Boy No. 4014, and now we’ll be excited to bring them to see the locomotive in person! Bring home these items yourself and you can rep your favorite magazine on the tour!
Union Pacific's Big Boys (Softcover)
Union Pacific's Big Boys: The complete story from history to restoration covers the who, what, why, and when of the 25 popular 4-8-8-4 steam locomotives. This book gives the historical background on the early 1940s development, explains why they were built, how they were used, and traces their history until they were retired in the 1950s.
This book also covers the much anticipated and well covered restoration of No. 4014 starting when it was recovered in a park in 2013 all the way through to its restoration and tour across the United States in the summer of 2019.
Visit shop.trains.com today to browse the complete collection of Big Boy No. 4014 merchandise and find the perfect way to celebrate this legendary locomotive.
-Written by Matt Herr.