An old school Cascade Green SD40-2 works the yard in downtown Denver, Colorado.

BNSF 1958 (SD40-2) leads the local to Hudson, Colorado where it will bring back a cut of oil cans to Denver.

BNSF 1958 (SD40-2) climbs out of the bowl at the large yard in downtown Denver, Colorado.

BNSF 1958 (SD40-2) crosses the South Platte River in Denver, Colorado.

BNSF 1958 (SD40-2) sorts a cut of cars in the yard in downtown Denver, Colorado.

A pair of old school Burlington Northern Cascade Green units head into the Denver Yard to sort freight cars.

BNSF 1958 (SD40-2) makes smoke as it pulls out a heavy cut of cars from the yard in Denver, Colorado.

A rare treat this day as a pair of old school Burlington Northern units sort cars in the massive yard in downtown Denver, Colorado.

BNSF 1958 (SD40-2) works the yard in Hudson, Colorado.

BNSF 1958 (SD40-2) leads the Hudson Local east on the Brush Sub through Brighton, Colorado.

BNSF 1958 (SD40-2) leads the local east on the Brush Sub towards Hudson, Colorado.

BNSF 1958 (SD40-2) leads a freight through Hudson, Colorado on the Brush Sub.

BNSF 1958 (SD40-2) shuffles a cut of cars in the yard at Hudson, Colorado.

BNSF 2028 (GP38-2) leads a cut of oil cans west on the Brush Sub through Tonville, Colorado.

BNSF 1958 (SD40-2) leads a stack train east on the Brush Sub through Tonville, Colorado.