Callan Bond’s review published on Letterboxd :
Entertaining early Hitchcock, The Lady Vanishes is a high-concept thriller that has had countless variations created since its debut over 70 years earlier. A socialite is caught up in a conspiracy when a kindly older lady that she befriends mysteriously disappears from the train she is on, and everyone around her denies that the missing lady was ever onboard.
While the opening 20 minutes or so could have used some trimming, once aboard the train the movie moves at a good clip with engaging characters and a compelling mystery. Although made right at the cusp of the 'noir' period, there's plenty of humor injected and the film doesn't feel like a film noir. There's also some nice allegory to Britain's involvement in WWII layered on at the end which gives a historical flavor to the movie without somehow making it seem dated.
At once entertaining and providing both satisfying cinematic and historical context, The Lady Vanishes is a solid early-Hitchcock entry.