A westbound Union Pacific coal train passes through Rocky, Colorado, on the pleasant afternoon of March 25, 2014.

Union Pacific GE AC4400CW-CTE No. 6049 operating as a DPU, pushes a westbound coal train into Big 10 Curve west of Rocky, Colorado, on March 25, 2014.

Approaching the west switch at Rocky, Colorado, Amtrak No. 6, the eastbound California Zephyr, descends the 2-percent grade off the Front Range of the Rocky Mountains on the afternoon of March 25,... (more)

Amtrak No. 6, the eastbound California Zephyr, passes through West Rocky, Colorado, on the afternoon of March 25, 2014. Carrying the markers is private car Sierra Hotel, a former Budd-built Dormit... (more)

Approaching the west switch at Rocky, Colorado, is Union Pacific’s MRONY manifest freight from Salt Lake City to Denver on June 9, 2013.

Union Pacific’s MRONY manifest freight train from Salt Lake City to Denver leaves the mountains behind as it heads eastbound through Rocky, Colorado, on June 9, 2013. On the rear of the train en... (more)

Eastbound approaching Rocky, Colorado, a summer version of the Rio Grande Ski Train returns to Denver on the afternoon of July 22, 2006.

An eastbound Union Pacific coal train drops downgrade off the mesa through Big 10 Curve west of Rocky, Colorado, on February 28, 2009.

As the head end of an eastbound Union Pacific coal train passes through Rocky, Colorado, in the background, lone DPU GE AC4400CW No. 6856 holds back the rear of the train while exiting Big 10 Curv... (more)

A westbound Union Pacific coal empty curves through “Little 10 Curve” at the west end of Rocky, Colorado, on the morning on June 2, 2013. The train will be on the foreground track momentarily ... (more)

Amtrak’s eastbound train No. 6, the California Zephyr, passes the mid-train DPUs of an eastbound Union Pacific coal load in the siding at Rocky, Colorado, on the afternoon of June 16, 2013. The ... (more)

Adding meaning to the phrase “S curve, ” Union Pacific’s Denver to Salt Lake City manifest freight MNYRO climbs the two-percent grade into Rocky, Colorado, on February 2, 2014. Four GE AC440... (more)

On a snowy February 2, 2014, westbound Union Pacific freight MNYRO is climbing the 2% grade between Rocky and Eisele (formerly Clay), Colorado. The head end is about to take down the signal at eas... (more)

After a nice Colorado snowfall, Union Pacific’s Denver to Salt Lake City manifest freight passes through Rocky on February 2, 2014. Four AC4400CWs are on the point, with a SD70ACe/AC4400CW DPU d... (more)

After picking up a tank car at Chem Spur, Union Pacific’s West Local heads for Rocky Spur through Barbara Gulch just east of Rocky, Colorado, on December 16, 1997. Powering the local are venerab... (more)