Hitchcock had had a rough time before making this little beauty. Trying to cope with making colour movies while maintaining a high standard of output while running his own production company while trying to find a replacement for Ingrid Bergman -- all of these things combined to form a 5-year waver in quality.
Strangers on a Train sees Hitchcock dump all that guff, head back to black and white, and pick up some favourite themes. The result is a lean, effective, engaging thriller.
Two strangers meet on a train, each of whom has someone they would rather get rid of. The more unbalanced of the two (Bruno, played by Robert Walker) hits on the idea that they could perform each others' murders and keep schtum -- problem solved. Trouble is, Bruno goes ahead with the idea, and expects whiter-than-white tennis ace Guy to follow suit.
Hitchcock deals with the chaotic strands of the story superbly, with some very strong themes helping to knit everything together. The criss-cross of the railway lines represent the converging storylines throughout. Walker is frightening and funny as the unhinged Bruno, with a healthy dose of camp suggesting a more primal obsession with Guy, very much in the Cape Fear mould. The theme of doubles is also carried through, with Bruno frequently presented as Guy's darker-than-dark side.
There are some excellent set-pieces, the murder of Guy's truly horrible wife being one of the best, and the climactic merry-go-round scene genuinely thrilling and convincing, even half a century on.
Great, harmful entertainment.