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Continuity mistake: The first scene that they show of the train going up the Hudson River is wrong. The hills in the background are much further up the river past Croton NY. When they are eating the train is back down near the wider part of the Hudson around Tarrytown NY. (00:45:25 - 00:47:00)

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Continuity mistake: In the last scene before Chicago the train is going through the tunnel at Breakneck Pass north of Cold Spring NY. When they're going back home at the end of the movie theoretically they should be going the same way but they're not. The final tunnel shot in North by Northwest is the Southern Pacific railroad tunnel between Santa Susana and Chatsworth California. (01:00:10 - 02:16:05)

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Audio problem: Near the end of the movie when Cary Grant says, "Come along Mrs. Thornhill." If you read lips he's actually saying, "That's it." (02:15:45)

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Continuity mistake: In the scene where Eve writes on the note pad she doesn't write enough. Later you can see much more to the address. (01:20:50 - 01:25:15)

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Continuity mistake: In the very first scene when the train pulls out of Grand Central Station you can see that the sun is setting. Then when they sit down to eat it's the middle of the day again. (00:45:25 - 00:46:50)

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