Something about train movies raises expectations. The mixture of claustrophobia and constant movement worked especially well in “North by Northwest,” “Source Code,” “The Narrow Margin” and “Murder on the Orient Express.”

A new British thriller, “Last Passenger,” works pretty well for its first two-thirds or so. Then it (almost literally) runs off the rails with a series of twists that ultimately invite more laughs than tension.

The hyperbolic script takes an Agatha Christie approach to the few remaining passengers on the last night train from London. They’re flirtatious or they’re suspicious-looking or they’re disappearing without a trace.

But who’s orchestrating the mayhem when the train picks up speed, loses its brakes and starts shooting sparks? Criminals? Terrorists? Someone on a suicide mission? Or someone who remembers that runaway bus movie, “Speed”?

Dr. Lewis Shaler (Dougray Scott) is a workaholic widower who lives to regret taking his young son Max (Joshua Kaynama) on the trip. Across the aisle is an all-too-available bureaucrat, Sarah (Kara Tointon). Not far away is the faintly sinister immigrant magician, Jan (Iddo Goldberg).

The director, Omid Nooshin (“Panic,” “The Patient”), explores the train with an extra-mobile camera that suggests the movements of a runaway submarine. The effect is so exaggerated that the actors are barely able to register.

Scott and Goldberg fare best, though the usually excellent Lindsay Duncan is wasted in a throwaway grandmother role.

The final act is so crowded with catastrophic events, all piled on top of each other, that even the sound effects and music struggle to make themselves felt.

John Hartl: johnhartl@yahoo.com