This is the Grand Canyon railroad.  Abandoned by the ATSF in 1974, it returned to operation in 1989 running from Williams to the Grand Canyon depot.  Starting as steam, it is now Alco FP4s in regular daily service,  the cars are a mix of coach, dome, and an observation.  Usually, the train leaves for the canyon at 10 in the morning and arrives back at Williams around 5:30 in the evening.  Sweet.