Continuity mistake: James and Edward are on the mainline at first, but then they overrun the platform at Dryaw station, which is on Thomas' branch line.
Other mistake: The narrator says that the fence was mended, but there is no fence and there never was.
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.