Continuity mistake: When James passes Edward at Knapford, Edward's train does not have a brake van. But two shots later, it does.
Continuity mistake: Thomas appears to be damaged and dirty after his accident but in the final scene, he is undamaged and clean.
Henry Gets the Express - S20-E3
Continuity mistake: Throughout the scene when he is at Brendam Docks, Gordon's paintwork is noticeably darker.
Continuity mistake: Sir Handel was just near the turntable when Samson approaches the Blue Mountain Quarry, but a few shots later, Sir Handel has moved to a siding.
Diesel and the Ducklings - S20-E4
Continuity mistake: When Diesel keeps James and Gordon waiting, they are at the top of the hill, but a few shots later, they are at the bottom of the hill.
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.