It is the largest steam locomotive in the entire world.

The Union Pacific Big Boy No. 4014 is on its Westward Bound Tour for the summer.

It's the largest steam locomotive in the entire world.

The train started in Cheyenne, Wyoming on June 30 and traveled across Wyoming, Utah, and Nevada before dropping into California. 

The Big Boy stands about 17 feet high and about 130 feet long.

25 of the locomotives were built to haul freight during World War II.

Eight were preserved after the locomotives were retired about 60 years ago, but the Big Boy No. 4014 is the only one still in operation.

The rich history is what made the Union Pacific want to bring it back to life in 2019.

"Why not rebuild the world's largest locomotive, the Big Boy, and that's what we did," said Ed Dickens, Manager of Heritage Operations for Union Pacific. "It just captures the imaginations of people. We know the train enthusiasts love the Big Boy."

Throughout the tour, Dickens said it has brought huge crowds.

"Crowds that we see here are like a rock concert," he said.

While the train itself is a huge spectacle, it does help out the local Portola Western Pacific Railroad Museum with an economic impact.

"I was just talking with some folks and they said 'we never knew you were here' and they said they're going to come back," said Eugene Vicknair, Operator at the Western Pacific Railroad Museum. "This is great up here and that just rolls down hill. It benefits the restaurants, the hotels, the working people in this community, as well as benefiting the museum and allowing us to grow." 

Vicknair says people came in from Singapore, the Netherlands, and Japan just to be here.

Some visitors said it was worth it.

"Man, I'm amazed by it," said Kinden Ramirez. "I do model trains, so I only see it in a little scale so it's great to see it in really life. It's a once in a lifetime opportunity." 

"When I first saw it I was speechless like I've never seen a train so big in my life and I've seen a lot of trains," said Isaiah Clark.