Thomas and the Missing Christmas Tree - S2-E26
Other mistake: In the shot of Donald, (or Douglas) Gordon and Henry, Donald has Edward's face.
Thomas the Tank Engine & Friends (1984)
1 other mistake in Thomas and the Missing Christmas Tree - chronological order
Starring: Alec Baldwin, Michael Brandon, Ben Small, Martin Sherman, Michael Angelis
Plot hole: When Duck and Diesel leave the shed, Diesel follows Duck instantly, but the tracks they are on both lead to the turntable. As they are on different tracks to each other, it would be impossible for Diesel to follow Duck that quickly as the turntable could only be set to one track at a time.
Duke: Excuse me. Are you a vandal? Driver told me vandals smash and break things.
More trivia for Thomas the Tank Engine & Friends
Question: Why was Henry put on a barge instead of being taken to the works?
Answer: He was in the water.