Without a doubt one of the best train-centered action movies out there. Based on the Alistair MacLean novel, Charles Bronson stars as a prisoner being transported on an army train bound for a remote mountain fort. Soon it turns into a murder mystery and he must prove his innocence.  

Railroad scenes were filmed on the Camas Prairie Railroad line in northern Idaho, which was sold off in the 1990s and abandoned in the 2000s. Great Western Railway's #75 locomotive was used as was several of its cars. 

The Myrtle settlement was a set built by the crew near Arrow Junction, ID (between Kendrick & Juliaetta, east of Lewiston). 

The film features spectacular footage of the Great Western train making its way along the old Camas Prairie line. Specific locations haven't been found yet. 

Soon the train climbs into the mountains. These scenes were filmed just west of Reubens, ID off U.S. Route 95. This stretch of the line features several massive wooden trestles and tunnels. The most prominent structure is the massive Halfmoon Trestle, which is 141' high. 

It doesn't take long before the back half of the train is cut loose and goes toppling off a cliff. 

As they come into a winter wonderland, Deakin (Bronson) must fight off an attacker atop the passenger cars, where they both soon end up dangling over a massive trestle. 

Deakin manages to make his way to the engine cab and gain control of the train, with the Marshal (Ben Johnson) and O'Brien (Charles Durning) in pursuit. 

This appears to be the Lapwai Creek Trestle (46°19'56.6"N 116°35'45.5"W), visible from Route 95. 

With Indians in hot pursuit, Deakin ditches the train and leaves it to O'Brien. 

The train is brought to a halt when they discover the tracks have been dynamited. 

Deakin and the Marshal have one last stand alongside GWRy #75. This famous movie locomotive passed on to the Heber Valley Railroad in Utah where it was brought back to operation in the early 2000s, but not for long. In 2002 it was taken out of service for a major overhaul and hasn't operated since.