World’s largest operating steam locomotive, Big Boy No. 4014

Big Boy No. 4014 was delivered to Union Pacific in December 1941 and retired just 20 years later after traveling over a million miles. Thanks to a multi-year restoration process, the railroad company said the train hit the tracks again in 2019 to celebrate the 150th anniversary of the Transcontinental Railroad’s completion.

Now, the train is up and running and heading through the United States on the “Heartland of America Tour,” which starts in Wyoming in late August. The train will travel across nine states, one being Colorado, on its eight-week tour.