Which 1938 Alfred Hitchcock thriller centers on the disappearance of Miss Froy from a train?

Which 1938 Alfred Hitchcock thriller centers on the disappearance of Miss Froy from a train? The thriller is The Lady Vanishes.

The film follows Iris Henderson, an English traveler who wakes on a train and discovers that her older companion, Miss Froy, has apparently disappeared. Other passengers insist Miss Froy was never there, making Iris question her own memory. She receives help from Gilbert Redman, a musicologist played by Michael Redgrave.

Adapted from Ethel Lina White’s 1936 novel The Wheel Spins, the film blends mystery, romance, comedy, and political suspense. Miss Froy is eventually revealed to be involved in a dangerous espionage plot, and the train journey becomes a fight to expose the conspiracy before it reaches the border.

The Lady Vanishes was one of Hitchcock’s major British successes before his move to Hollywood. It is often confused with Foreign Correspondent or Sabotage, other Hitchcock thrillers from the same period, but neither centers on a missing woman named Miss Froy. The principal cast also includes Margaret Lockwood and May Whitty.