[Quick Summary: On a train, a man with a problematic wife meets a stranger who offers to kill the wife -- if the man will kill the stranger's father.]
In the book, Guy meets a stranger on a train called Bruno.
Bruno agrees to kill Guy's wife, and Guy will kill Bruno's father.
However, in the script, Guy refuses, but Bruno kills Guy's wife anyway.
For the rest of the story, Bruno insists that Guy hold up his end of the "agreement."
Why doesn't the script include the double murder?
I'm not sure, but only one murder does dial up the psychological pressure on Guy.
ex. Bruno feels justified about invading Guy's social circle to drop hints.
ex. Guy cannot tell the police, so Bruno has eternal leverage over Guy.
ex. Bruno needs Guy to act immediately, which increases the urgency.
WHAT I'VE LEARNED: Hitchcock seems to have favored more tension here over a second murder plot line.
Strangers on a Train (1950)
by Raymond Chandler & Czenzi Ormonde
Adapted from the novel by Patricia Highsmith