Continuity mistake: Throughout the episode, rust stains disappear and reappear on Duncan's front buffers.
Samson at Your Service - S18-E24
Revealing mistake: James is shifted on his body when Samson leaves him.
Duck and the Slip Coaches - S18-E8
Audio problem: At the beginning, Edward has Thomas' whistle sound.
Audio problem: In the first shot, Duck's chuffing sound doesn't match his speed.
Revealing mistake: Some trucks are completely Off the Rails at the clay pits.
Revealing mistake: Duck's footplate clips through the platform at Knapford at the beginning.
Answer: Butch the breakdown truck must have pulled Gordon's tender all the way up the rails so the breakdown train can reach it and also Butch helped to get Gordon close to the winch.