McQueen
There is a point where Poirot (Albert Finney) is talking to Mr. McQueen (Anthony Perkins) and he is talking about his mother and how he still dreams about her and how she influenced him, ... You remember?
Anyway, the second or third time I saw this scene I thought "this is a reference to Psycho of which Anthony Perkins played the main character". It seems like it, but it must be a coincidence because, though "Murder on the Orient Express" was made in 1974, 14 years after "Psycho", the book was written in like 1934, and Anthony Perkins would have been 2 years old, and this was over 20 years before Psycho was filmed (maybe not written), and there's no way Agatha Christie could have known that Anthony Perkins would play him, right?
As an asied, I wonder what Agatha Christie would think of her grandson, the Governor of New Jersey. (Yes, that is a joke).