Corrected entry: Professor Fate tries to use a shortcut by following the train tracks. The RR crossing sign says (vertically) "Look out for the Cars" (rather than watch for trains). (01:16:55)
Corrected entry: Professor Fate's auto, when it raises itself off the running gear, has no means of propulsion. The drivetrain is not connected to the drive axles by either a driveline or chain.
Correction: The drive and steering are both hydraulic. You can see the hoses from several views.
Corrected entry: Note the scene were Professor Fate and Max are attempting a speed record with the rocket powered rail car. It appears the ignition of the rockets was much more violent than expected, as the crowd jumps in panic when the rockets fire, and retreat in disarray. This is so instantaneous that it does not look planned. Even the stunt doubles in the car cringe in their seats as the car takes off.
Correction: That sounds like a natural reaction. How is it a mistake?
Corrected entry: In the Potsdorf Palace waltz scene, during the Blue Danube waltz, the shot is centered on Tony Curtis dancing with an attractive young woman. However, directly behind him, Jack Lemmon is seen dancing with a uniformed military officer.
Correction: This is not a mistake but rather a character choice. Jack Lemmon's Prince Hapnik is goofy and free spirited, so it's quite plausible that he would grab any one of his loyal subjects to dance with, and would probably find it perversely funny to make an upright military man his waltzing partner.
Corrected entry: The closed-captioning (or subtitles) do not follow the dialog in the movie: (1)cc: "They said I never could" vs. the spoken dialog "Fate the Magnificent" and (2)cc: "what's more" vs. dialog "What's it for?" (the rope and grappling hook). (02:04:45 - 02:09:10)
Correction: The subtitle mistakes are the fault of a computer program. It is not a movie mistake.
Correction: "Look out for the cars" is a correct and authentic railroad crossing warning for the period. It was a standard phrase used in most parts of the U.S. from the 1800s to the 1950s. The vertical orientation is also authentic. I know this because such railroad crossings were common when I was a kid sixty years ago. My father (who had worked on the CB&Q railroad)explained that "cars" in this case meant railroad cars. My grandfather's railroad rule book from 1900 also confirms the authenticity of "Look out for the cars" as a railroad crossing warning.