Big Boy No. 4014 Becomes First Locomotive of Its Size to Cross Horseshoe Curve

Union Pacific's Big Boy No. 4014, the world's largest operating steam locomotive, rolled through Western Pennsylvania on Saturday, becoming the first engine of its scale to navigate Horseshoe Curve on its first-ever tour of the East Coast.

A 1.2-Million-Pound Engine Takes On Horseshoe Curve

The locomotive left Altoona at 9 a.m. and reached the Horseshoe Curve National Historic Site between 9:30 and 10 a.m., where the sharp Appalachian bend has drawn railfans for generations. At 133 feet long and 1.2 million pounds, No. 4014 is nearly 60 feet longer than a standard diesel engine, and some enthusiasts had doubted a locomotive that size could take the curve at all. The successful pass reflects the same engineering the Big Boy class was built for: hauling extreme loads through mountainous terrain without derailing on tight turns. From Horseshoe Curve, the train continued to a stop in Cresson between 10:45 and 11:15 a.m.

A Wartime Freight Hauler Built for the Wasatch Mountains

No. 4014 was built in 1941 by the American Locomotive Company to pull heavy wartime freight and military loads over Utah and Wyoming's Wasatch Mountains, one of just 25 Big Boy locomotives ever produced. The class name traces to an anonymous shop worker who chalked "Big Boy" on an early engine's front; the label stuck for the entire line. The locomotive holds 25,000 gallons of water and was retired from service in 1961. Union Pacific brought it back through a restoration that ran from 2013 to 2019, and it remains the only Big Boy still capable of operating under its own power — the eight other survivors exist only as static displays. Ed Dickens, the Union Pacific engineer who led that restoration, has called the tour "a trip of a lifetime."

Crowds Follow the Route From Derry to Leetsdale

After Cresson, the train rolled through Derry, Bradenville, Latrobe, Greensburg, and Jeannette between 1:30 and 2:35 p.m., where local watch parties combined tracking apps, food trucks, and, in Derry, a hobo costume contest. Steph Zemba of Brady's Train Outlet described the experience of the engine passing: "The ground shakes when it's coming. You can hear the whistle a mile away." In the afternoon and evening, No. 4014 crossed the Ohio River via the Brunot Island bridge and moved through the South Side Flats and Station Square before a scheduled stop in Leetsdale, at the Ferry Street railroad crossing near Subway, between 6:15 and 6:45 p.m. Union Pacific has asked spectators to stay at least 25 feet from the tracks because of flying debris and steam burns, and has specifically warned parents that the engine's whistle is loud enough to startle young children.

Overnight Stop in Conway Before Crossing Into Ohio

The train's final Pennsylvania stop comes overnight in Conway, ahead of a border crossing into Ohio on July 12. From there, No. 4014 continues its multi-state route back toward its home base in Cheyenne, Wyoming, after completing the first East Coast leg of a tour tied to the 250th anniversary of the United States. For communities along the Pennsylvania stretch, the run offered a rare look at a machine built for a different era of American transportation still capable of drawing crowds to the tracks.