Revealing mistake: During the scene of James and Duck at Knapford station, Duck's footplate is clipping through the platform.
Continuity mistake: Throughout the episode, rust stains disappear and reappear on Duncan's front buffers.
Samson at Your Service - S18-E24
Revealing mistake: James's chassis is incorrectly positioned when Samson passes him.
Duck and the Slip Coaches - S18-E8
Audio problem: At the beginning, Edward has Thomas' whistle sound.
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.