Before watching the movie:
This is one of those that nobody ever really discusses beyond the concept. A pair of strangers meet on a train and through conversation, discover that they both have someone they’d like to murder, and if they each just kill the other person’s target, they could both get away with it from having no apparent motive.
The only other thing people say about it is that it’s a Hitchcock film, which does more or less define a genre, or at least a tone. I also note that Raymond Chandler worked on the screenplay, so it should come off as a good detective story, assuming there’s a detective in it that nobody talks about. There has to be one, so there’s an antagonist, I assume.
After watching the movie:
Guy, a tennis star, is approached on a train by an animatedly creepy man named Bruno who knows all about Guy’s situation being married to the unfaithful Miriam but wanting a divorce so that he can marry Anne, the daughter of Senator Morgan, whom Guy intends to get help getting into politics from after his tennis career. Bruno has the idea that two strangers who each have someone they want to get out of the way might “swap murders”, thus neither murder having any apparent motive, for instance, if Bruno were to kill Guy’s wife, and Guy were to kill Bruno’s insufferable father. Guy tries to shrug off Bruno, but Bruno takes his words as interest in the proposition, and when Bruno calls Guy and learns that Miriam’s jealousy has led her to not only refuse to divorce Guy, but claim her pregnancy is from Guy in order to shut down any divorce suit from him, Bruno stalks Miriam at an amusement park and strangles her to death. Bruno then goes to Guy to tell him it’s Guy’s turn to complete his end of the arrangement. Of course, Guy wants no part of it, and further, as his alibi isn’t solid, he’s the prime suspect in Miriam’s murder. As the days wear on, Bruno becomes increasingly insistent that Guy either follow through on the deal or hang for the murder he benefited from.
I do now seem to recall some discussion about there being a misunderstanding and pressure between the two strangers, but it doesn’t come up much. It’s usually discussed purely in the terms of Bruno’s idea: a murder swap, the perfect crime. There are a couple of police detectives involved in the story, but only as minor characters assigned to tail Guy because they can’t prove he did it, but there’s also nothing persuasive to suggest that he didn’t.
The love story is nicely subdued here. Guy and Anne love each other and intend to get married, and eventually Anne gets let in on what Guy’s situation is and becomes part of his plans to get out of his predicament, but their love mostly just there to fuel Guy’s motivations rather than to be a throughline of interest. Anne and her sister Barbara mostly drive the plot through figuring things out, and are never imperiled or otherwise objectified.
The writing drew me in quickly. Even though the first scene and a half are very static, talky, and feel like a stageplay, they still command attention in a way most scenes that feel stagey don’t. Which is very good, as pretty much the entire plot happens in the first scene, which is when Bruno first meets Guy and lays out his entire plan and Guy brushes him off. Everything that follows from there is more or less either pure tension, or a development that increases the tension, until the ultimate resolution.
There’s much depth to be plumbed, and has been plumbed, from literary and cinematic analysis of this film. I consider a good Wikipedia page for a movie as one that has more than three paragraphs on the plot and some notes on the commercial success of a movie. The page for Strangers on a Train has more production notes and critical analysis than some classic prose pages, which is hardly surprising because of Hitchcock’s legend and highly documented devotion to perfection. I can’t really add anything to that body of analysis. It’s a highly textured, artfully executed, engaging movie that still stands pretty well against modern tastes. Not all Hitchcock movies have aged so well.