Revealing mistake: When Samson crosses the Vicarstown Bridge, there is no shadow effect on his face.
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.
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.