A Union Pacific Officer's Special passenger train runs through the aspen threes at Tolland, Colorado.

UPY 618 (GP15-1) was built in September of 1979 and can be found still working at the North Yard in Denver, Colorado.

Heavy snows blanket a colorful RTD commuter rail train as it runs pas the BNSF engine servicing facility in Denver, Colorado.

BNSF 6962 (ES44C4) waits for the green light to muscle an oil can train towards Pinecliffe, Colorado on the Moffat Tunnel Sub.

BNSF 4419 (Dash9) runs long hood forward as it heads into the Denver Yard where it will be lashed to an awaiting train.

Here is a wide-angle view of the BNSF engine servicing facility in Denver, Colorado.

CAGX 1134 (SW1200) works a cut of cars at the Commerce City Grain silo in Commerce City, Colorado.

BNSF 6962 (ES44C4) waits at the signals in Tolland, Colorado for the green light to move a freight.

Heavy BNSF motors are repositioning in the engine servicing facility as they will soon get order to head to the yard for a train assignment.

The California Zephyr runs through Tolland, Colorado on a sunny day.

The California Zephyr passes through a crossing in Wiggins, Colorado at sunrise.

Amtrak engine #194 (P42DC) backs the California Zephyr into Union Station in downtown Denver, Colorado. The myriad of catenaries support RTD's Commuter Rail trains that also use the station.

A Union Pacific motor sits at the servicing island at the BNSF engine facility in downtown Denver, Colorado.

BNSF 2718 (GP 39-2) heads to the Denver Yard to start the day sorting cars.

The iconic Union Station in downtown Denver, Colorado is home to the California Zephyr which visits twice a day (the westbound train 5 in the morning and the eastbound train 6 in the evening).