The California Zephyr is about to enter Tunnel 29 on the Moffat Line just east of Pinecliffe, Colorado and will be in Denver's Union Station about 90 minutes later.

A frosty Executive Grinstein MAC 9646 sits in the BNSF North Yard in Fort Collins during a snow storm.

A former Burlington Northern SD40-2 leads a freight through the S curve east of Sedalia, Colorado.

BNSF 6942 (ES44C4) rounds the corner with four mates and a long freight. It will soon pass through Tunnel #1 as it enters the Moffat Tunnel district.

BNSF 8105 (ES44C4) leads the east bound Z Train through the sweeping curve west of Keenesburg, Colorado.

The Union Pacific's Rio Grande Heritage #1989 spent a couple weeks working along the Colorado Front Range. Here we see it leading a southbound freight through the scenic area around Palmer Lake. ... (more)

Here we see two of the Denver Rock Island Railroad's switcher engines. DRIR 88 is a GP9R and DRIR 1083 (on the right) is a SW1500.

UP 8203 (AC45CCTE) runs back to the Union Pacific's North Yard under the signal block at the Federal Blvd RTD commuter rail station.

UP 7407 (ES44AC) leads a blade train through the curves on the Joint Line at Nixon, Colorado.

The low sun gives a golden hue to the amber grasses as UP 9039 (SD70AH) leads a freight through Peckham, Colorado.

BNSF 9229 (SD70ACe) brings a loaded coal through Lochbuie, Colorado. It will stop in Denver for a crew change and then proceed to Colorado Springs.

BNSF 6942 (ES44AC) leads a freight through Tunnel #29 east of Pinecliffe, Colorado.

A pair of MACs bring a freight down Mason Street in Longmont, Colorado.

The snow is falling fast as a BNSF crewman gets out to throw a switch in the BNSF North Yard in Fort Collins, Colorado.

BNSF 7042 (ES44C4) leads a Warbonnet and a mixed freight past the iconic red barn of the historic Greenland Ranch in Greenland, Colorado.