Continuity mistake: When Jack and the Duke are in the restaurant car of the first train, Jack is eating a chicken leg in one shot. In the middle of a sentence he changes to eating jelly and ice cream, which he finishes. In the very next shot his bowl is full of jelly and ice cream again.
Continuity mistake: At the beginning of the movie when Tony and Joey (Morons #1 and 2) meet Jack Walsh at the car rental desk, Tony writes a phone number on a packet of matches in pencil. Near the end of the movie when Jack Walsh fishes this pack of matches from his pocket, the phone number is written in pen.