UP Big Boy 4014 runs through the trees at Aroya, Colorado.

Union Pacific Big Boy 4014 runs between the cottonwood trees at Aroya, Colorado.

Railfans and photogs lined nearly the entire route between Kit Carson and Limon, Colorado, each no doubt marveling at the size and beauty of Big Boy 4014.

It was a beautiful sunny Colorado day as the world's largest steam locomotive, UP 4014 "Big Boy", runs past the trees at Aroya, Colorado. There were hundreds of people chasing this marv... (more)