Many films since have tried to make hay out of a similar concept, just how can a woman go missing from a moving train without anyone seemingly having seen her, but none have ever made for a movie quite as good as this genuine classic from 1938.
Of course the audience knows that Miss Foy, a delightful turn from Dame May Whitty, was on the train and we soon learn the reasons why the other passengers don't believe, or won't back up, Iris Henderson (another great turn from Margaret Lockwood) when she insists that the old woman has, well, vanished. Two bumbling Englishmen don't want to miss the test cricket, a lawyer doesn't get involved because he's in the middle of an illicit romantic affair.
When it was remade in 1979, badly, the action almost immediately cut to everyone meeting on the train; here almost 20 minutes elapses before we get to that point and the time invested at the beginning in this filling out of the story pays off superbly when the crunch comes further down the line giving the viewer a greater, and more logical, insight into the intimacy that has developed between the characters.
Margaret Lockwood and Michael Redgrave share a flirtatious rapport and the humour in the film is charming in the extreme. Throw in a little pre-war propaganda (although on this note, its interesting to watch the bumbling Englishmen of Charters & Coldicutt) and you have an admittedly light concoction, but one that is perfectly assembled. And as numerous subsequent attempts along the same lines have proved, it's impossible to improve on perfection.