Character mistake: Karen says the train she spotted was going north. There was no way to know which way the train was going to go.
Frosty the Snowman (1969)
1 character mistake - chronological order
Directed by: Arthur Rankin Jr., Jules Bass
Starring: Paul Frees, Billy De Wolfe, Jackie Vernon, Jimmy Durante
Continuity mistake: When Frosty gets off the train because Karen gets sick, from the magician's view it appears the train is slowing down and is very close to Frosty, but when the shot goes back to the magician, the train appears to be going much faster and is much further away.
The Magician: You silly children believe everything you see. When you're grown up, you'll realise that snowmen can't come to life.
Karen: But we.
The Magician: Silly, silly, silly.