Revealing mistake: After King Kong destroys the train track of the oncoming train, in the POV shot directly behind the train operator while he watches Kong rise from the broken track, the small model's support control bar is visible at the right as it moves up and down. The next shot is a close-up of the shocked motorman, and after he attempts to stop the train, there's another shot facing Kong with the control bar visible for a moment. (01:31:50)
Other mistake: While Ann Darrow is lying on the Empire State Building ledge beside the ladder, the backdrop shows the Chrysler Building, Queensboro Bridge, and Roosevelt Island, behind to the right. However, after Kong falls from the skyscraper, when Jack appears and says, "Ann, hang on, dear," this one shot is angled toward the left of the ESB, but the set's backdrop is positioned so it's the same background with the Chrysler Building, Queensboro Bridge, and Roosevelt Island, behind to the left. (01:38:20)
Continuity mistake: When King Kong carries Ann Darrow to the top of the Empire State Building, he places her on the ledge near the fixed ladder mounted to the building. During the scene, in Ann's close-ups, the ladder vanishes from where it should be, and in the zoom-in shots (biplane POV), the ladder is mounted in a different area than in the long shots. (01:35:00)
Revealing mistake: While King Kong is atop the Empire State Building, the biplanes are strafing their large target. There are several static close-up shots facing a biplane's nose, and in these "aerial" shots, there's a girder beneath the set prop's fuselage. (01:36:10)
Answer: It's never shown or explained, and the film uses a broad "suspension of disbelief" premise. The audience just accepts the characters were able to somehow transport a huge ape to New York City.
raywest ★