GILA BEND, AZ (3TV/CBS5) -- A historic steam locomotive is rolling through Arizona to celebrate the 150th anniversary of the completion of the Transcontinental Railroad.
Union Pacific’s “Big Boy 4014” departed Yuma for Casa Grande Wednesday, making stops in Mohawk and Gila Bend along the way.
Big Boy 4014 was originally delivered to Union Pacific in 1941, and recently underwent a two-year restoration. The behemoth 14-wheeled steam locomotive is 132 feet long and weighs 1.2 million pounds.
[WATCH: Big Boy draws big crowd]
"People are fascinated by the sheer size of this," said engineer Ed Dickens. "Watching it operate. Listening to the whistle. And just the experience and the ambiance of a steam locomotive is fascinating."
It’s the world’s only operating Big Boy.
In Gila Bend, hundreds of people lined the track to see it steam in.
"It brings back a lot of memories, and it's really fun to meet with all of these people and you all have this in common," said Rick Hogan, who came to check out the locomotive.
Young and old took pictures and soaked in the nostalgia as the train idled for about 20 minutes before continuing on its journey.
"Most generations alive now have never seen one," said Neil Kovash, who says he's always been fascinated by steam engines. "And this is probably my last chance to see one in operation for the rest of my life."
You can see the train's schedule online.