Union Pacific's Big Boy #4014 (4-8-8-4) gets greased up before continuing the trip to Denver on the old Kansas Pacific line.

UP Big Boy 4019 leaves Cheyenne with a great plume of smoke. Steam leaks can be seen surrounding the boiler.

Inside the cab of Union Pacific Big Boy 4005, which is on display at the Forney Museum of Transportation.

Union Pacific's Big Boy #4014 (4-8-8-4) leaves Sharon Springs, Kansas behind as it heads west towards Colorado.

"Dedicated Crew" On a hot July day in 2019, two dedicated workers from the Big Boy's Mechanical Crew perform routine maintenance on one of the largest steam locomotives in North America... (more)

Union Pacific's Big Boy #4014 (4-8-8-4) leaves Hugo, Colorado after stopping to lube of the running gear.

Union Pacific's Big Boy #4014 (4-8-8-4) runs through Speer, Wyoming as it returns to its home base at Cheyenne.

Union Pacific 4005, takes up a lot of space in the Forney Transportation Museum in Denver, Colorado.

Union Pacific's Big Boy #4014 glides across the plains east of Hugo, Colorado as it runs towards Denver.

Union Pacific Big Boy #4014 (4-8-8-4) gets ready to leave the UP's North Yard in Denver, Colorado and will heads back to home base in Cheyenne, Wyoming.

Union Pacific Big Boy #4014 leaves the Denver skyline behind as it heads towards Commerce City on the way back to home base in Cheyenne, Wyoming.

UP Big Boy #4014 (4-8-8-4) crosses a bridge west of Hugo, Colorado as the locomotive heads to Denver on the old Kansas-Pacific rail line.

Union Pacific's Big Boy #4014 backs under the signal bridge in Cheyenne, Wyoming as it finishes its second trip of the year.

Union Pacific's Big Boy #4014 (4-8-8-4) runs over a bridge spanning a wide arroyo in Peoria, Colorado.

Union Pacific's Heartland of America Tour with #4014 leading the way crosses Little Bijou Creek at Peoria, CO on the Limon sub.