UP 1957 (SD40N) shuffles a load of coal in the North Yard in Denver, Colorado.

A group of BSNF heavies sit in the downtown Denver engine servicing yard, waiting for either service or assignments.

BNSF 3945 (ET44C4) runs light through the Downtown Denver Yard.

Denver & Rio Grande Western GP-30 number 3006 on display in the Forney Museum of Transportation near downtown Denver.

The California Zephyr is led by Amtrak #160 "Pepsi" as it heads towards Tunnel #17 in South Draw, Colorado.

Amtrak #160 "Pepsi" heritage scheme (P42DC) leads the California Zephyr through South Draw on the Moffat Tunnel Sub.

Amtrak engine #60 (P42DC) in the "Pepsi" paint scheme back the California Zephyr into Denver Union Station.

Amtrak #160 (P42DC) in the "Pepsi" paint scheme arrives in Denver, Colorado with the California Zephyr.

BNSF 2585 (GP39-3) sits in the Denver Yard as the California Zephyr rolls by.

RTD commuter train #4128 (Hyundai Eagle P3) takes the elevated track over the California Zephyr, which is arriving at the Denver Yard prior to backing into Denver Union Station.

BNSF 3014 (GP40-2) sits in the engine serving yard along with a GP39 and the red caboose and white cars of the BNSF fire train.

UP 1957 (SD40N) works the North Yard in Denver, Colorado.

Here is a good look at DODX 39497, the Department of Defense's nuke cask heavyweight flatcar designed to carry spent nuclear fuel rods. It stopped by the yard in Denver for a few days.

Amtrak engine #71 (P42DC) leads the California Zephyr into downtown Denver, Colorado.

UP 737 (GP38-2) heads into the North Yard, passing a bay window caboose which is on the active roster and used as a shoving platform on trips to nearby businesses.