La Bête Humaine (1938, Fr.) (aka The Human Beast)

In Jean Renoir's classic, tragic, and film-noirish crime drama about murder, guilt and adulterous infidelity within a love triangle, adapted from Emile Zola's 1890 novel:

• the film's lengthy opening - the five-minute montage of a train speeding throughout the French countryside as two grimy engineers operated the train in almost perfect unison, during their regular trip from Paris to the port city of Le Havre (with the sounds of the whistling train roaring along the track, POV shots of the tracks ahead as the train came in and out of tunnels, and the blurred views of the countryside and buildings whizzing by)
• the main characters: homicidal, tormented railroad engineer Jacques Lantier (Jean Gabin) - the "human beast" who loved his locomotive (Lison), Le Havre deputy station master Roubaud (Fernand Ledoux), and his sexy, manipulative and troubled femme fatale wife Séverine Roubaud (Simone Simon)
• Lantier's description of his own violent tendencies (due to his father's alcoholism): "I feel like I'm paying for all those fathers and grandfathers who drank. All those generations of drunkards who poisoned my blood... It's like some thick smoke that fills my head and distorts everything. I'm like a mad dog that wants to bite"
• the scene of the night-train murder of philandering aristocrat M. Grandmorin (Jacques Berlioz), Severine's abusive godfather (Grandmorin was her mother's employer - and possibly her father!), who was robbed and knifed to death by her jealous husband Roubaud (with Severine in the same train compartment to serve as his accomplice) - a crime that was solely witnessed by bystander Lantier
• the sharing of the murderous secret between Severine and Lantier, for which he was rewarded with sex during a passionate love affair to keep his silence; to rid herself of her husband in a very unhappy marriage and her fatalistic view of life, she suggested that Lantier kill her husband: ("Tomorrow will be just like yesterday: the same grief and sorrow. It really doesn't matter. What happens, happens. All I can do is go on living my miserable life until Roubard kills me")
• Lantier and Severine attended a night concert in the railwaymen's ballroom (where they waltzed to a live band playing the tune of the popular French song "Le Coeur de Ninon" about a sad love affair); shortly later, the two of them were in her apartment - where his uncontrollable impulses led him to inexplicably strangle her and then stab her to death as she fought him off and screamed; the aftermath of her murder was juxtaposed - with masterful parallel editing - by a return to the dance hall scene where a singer was performing the same sad song
• the conclusion - Lantier confessed the crime to his understanding assistant-colleague stoker Victoire Pecqueux (Colette Regis): "I have something to tell you, but don't say anything, don't move. I've killed her. Yes, I've killed her. So now it's over. I won't see her anymore. I won't see her anymore and I'll die of it. I know I'll die of it. You know, I won't be able to hold her in my arms. I loved her, you know. What I loved most were her hands. I loved holding her little hands. One thing I don't understand, they haven't arrested me. Do you understand that?"; Pecqueux calmly suggested that he give himself up; and then shortly later after they set off on another train run, Lantier suicidally jumped to his death from the moving train

Lantier's Suicidal Death - and Eulogy Delivered By the Tracks

• Pecqueux found Lantier's body lying lifeless beside the railroad tracks, and closed his eyes; he then delivered a short eulogy: "Poor bloke. He must have been in pain to do that. I haven't seen him look so calm for a long time"; a conductor responded with the film's final line of dialogue: "We have to clear the line. We'll pull the train to the next station. I'll stay with him"