At 5:58 a.m. on June 4, 2014, a westbound BNSF manifest freight climbs through Rocky, Colorado, on Union Pacific’s Moffat Tunnel Subdivision.

Amtrak’s “Phase I Heritage” locomotive, GE P42DC No. 156, pilots the eastbound California Zephyr around Big 10 Curve west of Rocky, Colorado, on the afternoon of June 1, 2014. Nice, clean ai... (more)

It’s 6:39 a.m. on the morning of July 26, 2014, as a Union Pacific inspection train exits a cut just west of Rocky, Colorado. The three-car train includes power car UPP 207, sleeper “Portolaâ€... (more)

With freshly-washed EMD SD70ACe No. 8734 as power, a westbound Union Pacific inspection train aims into the morning sun toward Big 10 Curve west of Rocky, Colorado, just after dawn on July 26, 201... (more)

A Union Pacific inspection train approaches Big 10 Curve west of Rocky, Colorado, just after dawn on July 26, 2014. EMD SD70ACe No. 8734 leads power car UPP 207, sleeper “Portola” UPP 1610 and... (more)

Amtrak’s westbound California Zephyr leaves Rocky, Colorado, while climbing the 2% grades up the Front Range on August 26, 2013.

A westbound Union Pacific Xcel Energy coal train approaches Big 10 Curve west of Rocky, Colorado, on June 4, 2014.

As an eastbound Union Pacific freight drops downgrade through Little 10 Curve, a westbound BNSF freight waits patiently in Rocky siding. On this clear Saturday afternoon of June 28, 2014, the city... (more)

As a westbound BNSF manifest freight waits in Rocky siding, an eastbound Union Pacific freight rumbles by with UP No. 8066 holding down the rear as DPU on the nice clear Colorado afternoon of June... (more)

A former Southern Pacific GE AC4400CW leads five Armour yellow locomotives on a westbound coal empty leaving Rocky, Colorado, on August 26, 2013. Union Pacific No. 6263 was the former SP No. 267 i... (more)

At the west end of Rocky, Colorado, a westbound Union Pacific empty coal train climbs through Little 10 Curve. On the perfectly clear afternoon of June 9, 2014, the city of Denver is easily seen a... (more)

An eastbound BNSF manifest freight passes by the old hopper car windbreak at Big 10 Curve west of Rocky, Colorado, on the afternoon of June 9, 2014. In the background is the city of Denver which i... (more)

The lead locomotive of Amtrak No. 5, the California Zephyr, approaches Big 10 Curve west of Rocky, Colorado, on June 9, 2014. In the background sitting in the siding at Rocky is westbound Union Pa... (more)

Operating through a slow order, Amtrak No. 5 crawls over the fill on the approach to Big 10 Curve west of Rocky, Colorado, on June 9, 2014. A section of track on the fill was just lifted and hand-... (more)

Just west of Rocky, Colorado, on June 9, 2014, a Union Pacific Freightliner truck equipped with a Builtrite Handler lifts the rails for some hand tamping of the track and another very temporary fi... (more)