Hitchcock and railways go together like a locomotive and tender. He loved them, they figure significantly in his work and never more so than in The Lady Vanishes. Much of what happens could only take place on a railway line – passengers delayed together by an avalanche; classes compartmentalised; strangers trapped together as they’re transported across a continent; an engine driver killed in crossfire; a carriage disconnected and shunted on to a branch line; an intrepid hero struggling from one carriage to another outside a fast-moving train as other locomotives rush by; clues in the form of a name traced in the steam on a window, and the label on a tea packet briefly adhering to another window; and above all the enforced intimacy on this rhythmically seductive transport moving on its own tracks, independent of the changing landscape around it.

The Lady Vanishes is one of the greatest train movies from the genre’s golden era, challenged only in the master’s oeuvre by North By Northwest for the title of best comedy thriller ever made. Except for the opening sequence at an inn in a central European village, it takes place on an express train that has only two official stops in the course of its journey across the authoritarian central European country of Banrika. During this suspenseful voyage, a middle-aged British spy posing as Miss Froy, an eccentric governess, and carrying the film’s MacGuffin, is abducted by foreign agents, and her disappearance is covered up. Shot on a modest budget, largely at the small Gainsborough studio in Islington, it never seems cramped or corner-cutting (though it’s calculatedly confined), and it zips along with the speed of the Eurostar. In his 1966 interview book, Le Cinéma Selon Hitchcock, Truffaut told the master that every time he saw the film he intended to study the train’s movements, the editing and the special effects, “but each time I become so absorbed with the story that I’ve yet to figure out the mechanics of that film”.

The casting, in which Hitchcock was closely involved, was perfection, most crucially that of Margaret Lockwood and Michael Redgrave as Iris and Gilbert, the attractive romantic couple at the centre, who meet cute, bicker beautifully and share a delightfully British sense of humour. Both became stars in this picture and proved themselves the equals of such sophisticated 30s Hollywood couples as Powell and Loy, Grant and Hepburn, Lombard and Gable. But although The Lady Vanishes comes up fresh whenever one sees it, it’s a film that derives its depth and urgency from the troubled times in which it was made. It was shot during the spring and summer of 1938 in the months leading up to Neville Chamberlain’s capitulation at Munich, and Iris and Gilbert are passengers on a ship of fools, a compartment of British clowns adrift in a hostile Europe, surrounded by inimical foreigners in a world on the brink of war.

Gilbert is a politically naive musicologist collecting folk songs in the Balkans. Iris is a spoiled heiress returning to England to marry a chinless aristocrat for his title. In the adjoining compartments are a pompous barrister (Cecil Parker) and his mistress (Linden Travers), both cheating on their spouses and more concerned about their social status and professional future than their moral and civic responsibilities. Likewise, the blinkered Charters and Caldicott won’t let more serious obligations stand in the way of getting back to England to see the test match at Old Trafford. Only Miss Froy (Dame May Whitty), the courageous little old lady, is there to carry the torch for Britain and bear the vital MacGuffin (in the form of a state secret encoded in a piece of folk music) that may save the nation. Except for the barrister, who dies waving a white flag in the belief that the totalitarian enemy will respect Geneva conventions, they all turn up trumps at the end, just as Britain was to do at the last minute when war came in 1939. The expatriate Brits, however, are ultimately saved through the self-sacrifice of the only working-class English person aboard (Catherine Lacey). She’s a woman disguised as a nun (the working-class Hitchcock’s Catholicism comes out here) who has been inveigled into working for the evil schemer of Bandrika. As a prophetic commentary on its troubled times, on a world living under the storm clouds that are about to unleash the lightning of the second world war, The Lady Vanishes stands alongside two films of the following year that offer allegorical images of countries on the point of confronting cataclysmic events: John Ford’s Stagecoach and Jean Renoir’s La Regle du Jeu.

The Lady Vanishes was Hitchcock’s penultimate film in pre-war Britain, his greatest critical and box-office success up to that time. Frank S Nugent, the New York Times critic, and later to become Ford’s regular collaborator, immediately chose it as one the year’s best 10 pictures, writing: “If it were not so brilliant a melodrama, we should class it as a brilliant comedy. Seeing it imposes a double, a blessedly double strain: when your sides are not aching from laughter your brains are throbbing in an attempt to outguess the director.” In the New York Herald-Tribune, Howard Barnes went even further: “The Lady Vanishes is a product of individual imagination and artistry quite as much as a Cézanne canvas or a Stravinsky score.” When it opened in London’s West End in the autumn of 1938, it was the first time Hitchcock had seen his name above the lights in a film’s title, and he had his lap of honour, driving around Leicester Square, relishing the spectacle.