Having served in Korea, Jeff (Glenn Ford) comes back home and resumes his job on the railroad. His supervisor, Buckley (Broderick Crawford), is consumed by suspicion that Vicki (Gloria Grahame), his wife, is having an affair with her former employer, a man of considerable means. When she arrives back one evening, he demands she compose a letter designed to entice this gentleman onto a train in an empty compartment—and then things proceed as planned... Except Jeff also happens to be aboard the train and ends up interfering with their escape plan. She now perceives an opportunity to free herself from her husband's controlling nature and begins attempting to charm a new acquaintance, while trying to get him to put a heavy wrench to good use. Graham is quite captivating in her portrayal of a deceptive woman, and Crawford also does well as the often-inebriated spouse. Ford, however, was surprising for me; I’ve always considered him an unremarkable performer—like Alan Ladd, he never seemed capable of truly bringing a character to life. But here, he provides a fairly believable depiction of a man slowly caught in Vicki's carefully laid scheme. The ending also took me by surprise; it felt satisfying and conclusive. It moves along at a decent speed with a script that stands out for its conciseness more than any particular brilliance, and the three actors collaborate to present a worthwhile drama.

Source on TMDB