Continuity: When Poirot and Mr. Ratchett first meet in the restaurant car, Poirot has to correct Ratchett's pronunciation of his name. Poirot then points with his right hand toward Ratchett, but when it cuts to a close-up of Poirot, both his hands are on the table. The angle changes back, and Poirot's hand is once again lifted.

Continuity: Hercule Poirot takes the German maid to her cabin to look for photographs. She removes her suitcase from the shelf and opens it, showing a very obvious shot of a porter's tunic with many very shiny buttons and space for the missing button (evidence found earlier by Lauren Bacall). The shot cuts away and then immediately back, by which time a porter's hat has appeared on top of the tunic covering all of the buttons previously in shot.

Continuity: When Mr. Hardman is interviewed by Poirot, he states "I'm not a theatrical agent," while gesturing with his right hand. The angle changes to show Mr. Hardman from the front, and both his arms are suddenly on the armrests of his chair.

Factual error: The same locomotive is used for the entire run of the train, from Istanbul to northern Yugoslavia. This is impossible - locomotives would have been changed at the Greek, Bulgarian, and Yugoslav borders, at Belgrade, and perhaps at Nice.

Continuity: During the flashback to the murder, watch closely right after Mary Debenham stabs Mr. Ratchett. One moment she is in the room, the next she is back in the doorway.

Continuity: In one of the flashback scenes, as the drugs start working on Mr. Ratchett, in a close-up he is holding the last anonymous letter in both hands. Ratchett then removes his glasses with his right hand, and places that hand on his forehead. Back to a close-up of the letter and the letter is in both hands, but when it cuts he is holding the letter with only his left hand again.