The Plymouth Express Affair
Originally published in the April 1923 issue of The Sketch in the United Kingdom, The Plymouth Express is one of Agatha Christie s short stories. The Blue Book Magazine in the United States published the story in January 1924. The Under Dog and Other Stories, a 1951 American anthology, featured the story. The story was collected and published in the United Kingdom in 1974 as part of an anthology titled Poirot s Early Cases.
Five years later, the novel The Mystery of the Blue Train was written from the same basic premise as the short tale, but with different characters and settings.