This enjoyable western starring Robert Mitchum and George Kennedy features some great shots of the Denver & Rio Grande Railroad - which exists today as the Cumbres & Toltec Scenic RR and Durango & Silverton Narrow Gauge RR. After a storied list of film credits over the decades, the massive fleet of steam locomotives and rolling stock were divided up among the two operations and still run today. 

The film doesn't waste any time - right off the bat we're treated to some excellent traveling shots of D&RGW's #483 (as #550) pulling a freight train through the Colorado Rockies. 

We see the train arrive at the "Progress" depot - actually a set built by the crew at the Lobato siding just north of Chama, NM. This depot was left after filming and used in other productions. GPS Coordinates: 36°57'07.2"N 106°32'36.0"W

Once they switch to shots in the actual town of Progress we're on the Laramie Street set on the Warner Brothers Burbank backlot (R.I.P.). 

Back at Lobato siding. Today, you will pass this location on the Cumbres & Toltec Scenic Railroad, where basically all that remains are the livestock pens. 

Some excellent shots of #483 steaming along (now numbered #577). Today, this engine is part of the fleet at Durango & Silverton Narrow Gauge Railroad, although not currently operable. Our heroes have a shootout on top of the train as it passes over several highlights of the scenic railroad. Larry Jensen's excellent Hollywood Railroads Volume 3: Narrow Gauge Country contains specifics about the locations and cars used. 

Toward the end of the sequence, a couple gets their car stuck on the tracks in front of the oncoming train at the crossing by the depot. You can guess how this ends...

The train continues on with a legion of men on horseback and cars giving chase. 

As they come across a destroyed trestle, you know it's not going to end well. The spectacular crash was done with a large-scale miniature train.