Alistair MacLean spent most of his novelist days writing wartime suspensers or twisting, turning thrillers. The one book that he wrote which doesn't fit either of those descriptions is Breakheart Pass, a western set aboard a train. This film version of it is surprisingly enjoyable, and features the added bonus of an expressive, colourful characterisation by Charles Bronson.
The train is travelling to a fort in the Wild West with medical supplies to cure an outbreak of a nasty disease. However, some of the soldiers aboard the train are mysteriously disappearing, and anyone who's ever seen a film like this will figure out straight away that there's a murderer on board. Furthermore, the train must make its journey across hostile Red Indian terrain, where a fearsome ambush or a sabotaged stretch of track is only a spear throw away.
Bronson plays a mysterious outlaw who is held prisoner on the train, though there are plenty of clues that he may not be exactly who he says he is. Other well delineated characters are played by Richard Crenna, Jill Ireland, Archie Moore (yes, the boxer!), and Ed Lauter. One truly amazing sequence involves a rooftop scuffle between Bronson and Moore.... indeed most people who have ever seen the film remember it for that sequence more than any other. All things considered, Breakheart Pass is one of the better adaptations of a MacLean novel, admittedly not quite in the same league as Fear is the Key or Where Eagles Dare, but definitely worth seeking out, especially on DVD.