Watch Nunn Grow! On a hot summer afternoon (over 100 F!), UP 844 leads UP's Challenger, 3985, through Nunn, Colorado on the way to Denver on the Greeley sub. This is a positioning move in preparation for the annual Frontier Days train from Denver to Cheyenne and return. On the day of the trip, the Challenger will experience mechanical issues and will have to be removed north of Denver. Shot on Fuji Provia 100F.