Thousands of people lined railroad tracks across Nevada and California this month to see one thing — the world's largest operating steam locomotive, on tour to celebrate the country's 250th birthday.

The engine, called Big Boy, could be heard from miles away. Crowds lit up at the first sound of its whistle. As it approached, the ground shook, the vibrations running through the soles of spectators' feet. Thick plumes of steam billowed from its smokestack.

Union Pacific 4014 was built in 1941 as part of a family of 25 Big Boy class locomotives built to haul freight from Utah to Wyoming. Restored in 2019, it is one of eight that still exist today and the only one operational. 

This spring, the Big Boy embarked on a coast-to-coast tour to mark the 250th anniversary of the signing of the Declaration of Independence on July 4. The first leg of the journey crossed four states in the West, including Nevada and California. 

The train made stops in several Northern Nevada communities including Gerlach (population 130), where it seemed like the entire town turned out to watch. Families from other Nevada towns such as Fernley drove up to Gerlach just to catch a glimpse.

Originally scheduled to pass through Reno, the train was ultimately rerouted because of a spring snowstorm in the Sierras. Instead, it paralleled California State Route 70 between Marysville and Portola, drawing thousands of followers who trailed it by car through severe weather. 

Though the detour avoided heavy snowfall, torrential rainfall drenched photographers waiting along the route. The train also faced delays along the way, making for a cold and soggy day, but fans seemed undeterred from getting their dream photos of a steam locomotive along the Feather River. 

Now making its way back east through Nevada, the Big Boy is bound for its home base in Cheyenne, Wyoming, to prepare for the next leg of its journey toward the East Coast.