Union Pacific RR had 25 1.2 million lb Big Boy locomotives built starting in 1941. The one pictured , No. 4014, is the only one of eight still in existence that is still functioning. They were built to handle the steep terrain between Cheyenne and Ogden. This photo was taken on July 30, 2019, near DeKalb, IL. Union Pacific had the old engine doing a run across America. It was billed as a chance for rail fans across the country to view the newly restored engine as it made its run which commerated the 150th anniversary of the completion of the transcontinental railroad.