The California Zephyr runs through the North Yard in Denver, Colorado.

UP 1502 (GP40M-2) is a 52 year old former Baltimore & Ohio, CSX, and Southern Pacific motor which was built in 1971.

UPY 691 (GP15-1) works the North Yard in Denver, Colorado.

An inbound UP freight led by UP 8013 (AC45CCTE) passes under the signal bridge before entering the North Yard in Denver, Colorado.

The BNSF orange pops against the snow as light and heavy power wait for servicing or train assignments.

ATSF train 101, the Centennial State, is seen leaving Denver in 1950. Otto Conrad Perry photo, from my collection.

Webb Rail's Budd-built Pullman "Pacific Union" (former Union Pacific Railroad) and Budd built Pullman observation/diner car "Babbling Brook" (former New York Central Railroad) ... (more)

UP 1357 (GP40-2) works the North Yard in Denver, Colorado.

The doors are open on a hot day as UP 1957 (SD40N) heads for the barn after a day of sorting cars.

The remote operator of UP 1957 (SD40N) catches a ride back to the barn after a day of sorting cars in the North Yard.

UP 1817 (SD40N) heads deeper into the North Yard in Denver, Colorado to sort train cars.

UP 1817 (SD40N) gets repositioned in the North Yard in Denver, Colorado.

The California Zephyr leaves Denver Union Station and passes under the Park Avenue Viaduct on its way to the Moffat Tunnel sub and the Colroado Rocky Mountains.

An electrician carefully checks a circuit board from Union Pacific GE ES44AC No. 7682 on Track 5 inside the Diesel House at Union Pacific’s Burnham Shops on December 16, 2015. These former Rio G... (more)

Union Pacific UPY 577 has maintenance work done on Track 2 in the Diesel House at the railroad’s former Rio Grande Burnham Shops in Denver, Colorado, on December 8, 2015.