Audio problem: Edward has Thomas' whistle sound when he first sees Trevor and when he approaches Wellsworth Station.
Continuity mistake: When Edward stops at the station, a close up of his whistle shows the sky is sunset dark, but when he arrives, it's bright daylight.
Visible crew/equipment: When Edward sees Trevor for the first time, the edge of the set is reflected on Edward's boiler.
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.