Just after the train starts out, we see it on a high bridge; behind the locomotive and tender are a van, four passenger cars, and another van. Just after the lady vanishes, an exterior view along the side of the train shows at least five passenger cars, and we were told that there have been no stops.
when the doctor leaves the supposedly drugged lead characters in the compartment, he locks the door behind him so Gilbert has to climb to the next one through the window; when he comes back to Iris, the door is not only unlocked, but also wide open and we can see her exercising.
In Europe, the hotel manager says it is "spring" when talking about the avalanches. However, the two English travelers are trying to get back to England for the Manchester cricket test, which was always played in July.
In the noisy dancing scene above Lockwood's hotel room, the clarinet is shown with the mouthpiece turned with the reed upwards. Normally the mouthpiece is turned so that the reed is downwards, but in some European folk traditions the clarinet was played with the mouthpiece "upside down".
In the opening scene of the movie, the camera tracks downward in an aerial view over the side of a snow-covered mountain to show railroad tracks and the front of a train's locomotive buried by an avalanche, close to a train station in a small mountain village. As the camera passes over the train and four railroad officials standing to the left of it, one of the officials swivels to the left and then to the right, as if he were rotating on a pivot. As the camera moves closer to the ground, away from the train station and along a village street at ordinary eye level, it shows an automobile crossing the far end of a street; the string pulling the automobile along the street is plainly visible for an instant. Both this detail and the movement of the railroad official show that the entire opening scene was shot upon a scale-model miniature set.
The goof items below may give away important plot points.
When Doctor Hartz holds Iris and Gilbert at gunpoint, he seemingly sits on a seat in the middle of the compartment. When Iris and Gilbert get up after Doctor Hartz leaves, they walk to the door between the compartments and right through where the seat should have been.