Continuity mistake: 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 mistake: 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.
Question: Who was the person Poirot saw wearing the white dressing gown? And why did this person place it in his compartment? To plant "red herrings" like these do not draw attention away from the people on the train, but tells Poirot plain and simple that the murderer did NOT leave the train, but it still on board. So why bother doing it at all, as it only goes against their carefully planned cover story?Twotall