This is very cogently a follow-up to the scoop of The Lady Vanishes, with the Hitchcock factor acknowledged in the surreptitious note in a biscuit platter towards the end and elaborated in the tram climactically sliding over the Swiss border. Mostly, however, Carol Reed documents a "before" and "after" of his own, the uncomplicated morality of wartime action (further surveyed in The Way Ahead) on its way to the caustic relativism of its aftermath (The Third Man, certainly). The conflict is telescoped in a one-two punch, Hitler glimpsed from afar frothing in his mountain chalet and pounding the maps of European countries, on which marching feet are superimposed; Austria and Czechoslovakia fall, the fate of a key Czech scientist (James Harcourt) is discussed with the British intelligence until the meeting is broken up by the roar of approaching warplanes ("Ours?" "No. Theirs."). Margaret Lockwood, Harcourt's daughter, escapes from a concentration camp with the help of prisoner Paul Henreid, who accompanies her to England and, discovering the scientist's hideout, clicks his heels and lets out a Sieg Heil. No less than in To Be or Not to Be, war here is a matter of role-playing, or, to be exact, disguises and uniforms: Secret agent Rex Harrison is introduced on a wharf stage warbling "Only Love Can Lead the Way," then trades straw hat and jaunty cane for monocle as "Major Herzog," sharing the titular express with Lockwood, Harcourt and Henreid. England's WWII entrance is the topic, though the Sidney Gilliat-Frank Launder screenplay keeps it dry by satirically bestowing most of the patriotic commitment on Basil Radford and Naunton Wayne, Charters & Caldicott from the earlier movie -- news of war reach their ears, the two sit disconsolately by the train station ("Good heaven! My golf clubs... I left them in Berlin") and choose between Gone with the Wind and Mein Kampf, sauntering to save Harrison's endangered charade in Gestapo drag. With Felix Aylmer, Wyndham Goldie, Roland Culver, Eliot Makeham, and Raymond Huntley. In black and white.
--- Fernando F. Croce