1938 The Lady Vanishes

"Travelers on a trans-European train are stopped for the night due to bad weather and are hosted by a local hotel. Iris Henderson meets an old woman, Miss Froy who disappears as the journey begins again. Iris, helped by the musician, Gilbert, decides to find her." IMDB user

This film is the premise upon which Berlin Express (http://www.imdb.com/title/tt0040155/) and Night Train to Munich (http://www.imdb.com/title/tt0032842/) were

Respect to the SIS, SOE, and SAS...