Union Pacific’s Salt Lake City to Denver (MRONY) freight rounds Big 10 Curve west of Rocky, Colorado, on June 9, 2013. Far below on the edge of the Great Plains sits the sprawling city of Denver, with the city of Arvada seen between. From UP ES44AC No. 7977 on the lead of this eastbound freight, downtown Denver is 16 miles away as the crow flies. Just to the left of the train is the Arvada Associated Modelers Airpark for flying radio-controlled airplanes.