The American title of Murder in the Calais Coach was used to avoid confusion with the 1932 Graham Greene novel Stamboul Train, which had been published in the United States as Orient Express.

[6] After taking the Taurus Express from Aleppo to Istanbul, private detective Hercule Poirot arrives at the Tokatlian Hotel, where he receives a telegram prompting him to return to London.

When Poirot rings his bell for water, Michel informs him that the train is stuck in a snowdrift between Vinkovci and Brod before he hears a loud thump next door.

Her grieving husband, Colonel Armstrong, shot himself, and Daisy's French nursemaid, Susanne, was accused of aiding Cassetti and killed herself, only to be found innocent afterwards.

While the passengers and Pierre all provide suitable alibis for each other, Poirot notes that some of them observed the woman in the scarlet kimono walking down the hallway on the night of the murder.

Miss Debenham inadvertently reveals she has been to America, contrary to her earlier statements, and Ohlsson shows much emotion when the subject of Daisy is brought up, causing further suspicion.

[7] Flooding from rainfall that washed sections of track away in December 1931 halted Christie's return from her husband's archaeological dig at Nineveh aboard an Orient Express for 24 hours.

"[9] In The New York Times Book Review of 4 March 1934, Isaac Anderson wrote, "The great Belgian detective's guesses are more than shrewd; they are positively miraculous.

Although both the murder plot and the solution verge upon the impossible, Agatha Christie has contrived to make them appear quite convincing for the time being, and what more than that can a mystery addict desire?

"[10] The reviewer in The Guardian of 12 January 1934 noted that the murder would have been "perfect" (i.e. a perfect crime) had Poirot not been on the train and also overheard a conversation between Miss Debenham and Colonel Arbuthnot before he boarded; however, Poirot's "'little grey cells' worked admirably, and the solution surprised their owner as much as it may well surprise the reader, for the secret is well kept and the manner of the telling is in Mrs Christie's usual admirable manner.

[15] John Moffatt starred as Poirot in a five-part BBC Radio 4 adaptation by Michael Bakewell, directed by Enyd Williams, and originally broadcast from 28 December 1992 – 1 January 1993.

André Maranne appeared as Bouc, Joss Ackland as Ratchett/Cassetti, Sylvia Syms as Mrs Hubbard, Siân Phillips as Princess Dragomiroff, Francesca Annis as Mary Debenham, and Peter Polycarpou as Dr. Constantine.

The voice cast featured Vsevolod Yakut as Poirot, Rostislav Plyatt as Colonel Arbuthnot, Maria Babanova as Hubbard, Oleg Yefremov as Hector McQueen, Leonid Kanevsky as Antonio Foscarelli, Angelina Stepanova as Princess Dragomiroff and Alexander Lazarev as Hardman.

The film starred Albert Finney as Poirot, Martin Balsam as Signor Bianchi, George Coulouris as Dr Constantine, and Richard Widmark as Ratchett/Cassetti, with the remaining cast of suspects including Sean Connery (Arbuthnot), Lauren Bacall (Mrs Hubbard), Anthony Perkins (MacQueen), John Gielgud (Beddoes), Michael York (Count Andrenyi), Jean-Pierre Cassel (Pierre Michel), Jacqueline Bisset (Countess Andrenyi), Wendy Hiller (Princess Dragomiroff), Vanessa Redgrave (Mary Debenham), Rachel Roberts (Hildegarde Schmidt), Colin Blakely (Hardman), Denis Quilley (Foscarelli), and Ingrid Bergman (Greta Ohlsson), who won the 1974 Academy Award for Best Supporting Actress.

Only minor changes were made for the film: Mary Debenham was the Armstrong's secretary rather than Daisy's governess; Masterman was renamed Beddoes; the dead maid was named Paulette instead of Susanne; Helena Goldenberg became Helena Grünwald (which is German for "Greenwood"); Antonio Foscarelli became Gino Foscarelli; Caroline Martha Hubbard became Harriet Belinda Hubbard; and the train company's Belgian director, Monsieur Bouc, became instead an Italian director, Signor Bianchi.

[19] On 29 September 2016, the studio issued a press release announcing much of the cast, including Johnny Depp as Ratchett, Michelle Pfeiffer as Mrs Hubbard, Penélope Cruz as Pilar Estravados (a Spanish version of Greta Ohlsson, the name coming from a character in Hercule Poirot's Christmas),[20] Judi Dench as Princess Dragomiroff, Derek Jacobi as Masterman, Leslie Odom Jr. as Dr Arbuthnot, Daisy Ridley as Mary Debenham, Lucy Boynton as Countess Andrenyi, Tom Bateman as Monsieur Bouc,[21] Manuel Garcia-Rulfo as Biniamino Marquez (a Cuban version of Antonio Foscarelli),[22] Josh Gad as Hector MacQueen,[23] Marwan Kenzari as Pierre Michel,[24] Sergei Polunin as Count Andrenyi,[25][26] Willem Dafoe as Cyrus Hardman,[27] and Olivia Colman as Hildegarde Schmidt.

This version co-starred Meredith Baxter as Mrs Hubbard and Leslie Caron as Señora Alvarado (based on Princess Dragomiroff, and portrayed as the widow of a South American dictator).

Poirot is portrayed as significantly younger and less eccentric than Christie's detective, and is given a subplot involving a romantic relationship with Vera Rosakoff, who is loosely based on an infrequently recurring character of the same name.

The story is updated to a contemporary setting, and four of the suspects (Hildegarde Schmidt, Cyrus Hardman, Edward Masterman and Greta Ohlsson) are deleted, as is Dr Constantine.

The cast includes Dame Eileen Atkins as Princess Dragomiroff, Hugh Bonneville as Masterman, Jessica Chastain as Mary Debenham, Barbara Hershey as Mrs Hubbard, Toby Jones as Ratchett, and David Morrissey as Colonel Arbuthnot.

The character Cyrus Hardman (the former American police officer turned private detective) has been largely amalgamated with the chauffeur Foscarelli (inasmuch as being the lover of the dead maid) and Dr Constantine (who in the novel is unrelated to the murders) becomes a coconspirator, depicted as having been the Armstrong family's doctor in America.

The ending dwells on Poirot's horror at the act of mob justice and his moral conflict, in view of his Catholic faith and commitment to the law, when he decides not to tell the Yugoslavian police what he knows.

The interior of the Orient Express was reproduced at Pinewood Studios in London, while other locations include the Freemason Hall, Nene Valley Railway, and a street in Malta (shot to represent Istanbul).

[30] A Japanese adaptation was broadcast over two nights in January 2015 on Fuji Television,[31] titled Orient Kyuukou Satsujin Jiken [ja], and it featured several famous actors, including Ninomiya Kazunari, Matsushima Nanako, Tamaki Hiroshi, Kichise Michiko, Nishida Toshiyuki, and Sawamura Ikki.

[32] American playwright Ken Ludwig adapted the novel into a play, Murder on the Orient Express, which premiered at the McCarter Theatre in Princeton, New Jersey on 14 March 2017.

[34] On 12 September 2023, Murder on the Orient Express was adapted into an authorized graphic novel illustrated by Bob Al-Greene and published by William Morrow Paperbacks.

Having one prologue and thirteen chapters, Agatha Christie – Murder on the Orient Express faithfully adapts and modernizes the novel's plot, with the main characters retaining their original names and using mobile phones and computers.

For four years, Locke has been investigating the kidnapping and murder of Daisy Armstrong, and boarded the Orient Express in a failed attempt to arrest Cassetti for the crime and prove Susanne's innocence.

While the first eight chapters of the game adapt the entire novel, a twist expands the plot by adding a thirteenth killer, who had murdered Cassetti before the Armstrongs' and Susanne's loved ones unleashed their revenge on him.