Santa's Little Engine - S17-E18
Revealing mistake: At one point, the shading effect on Thomas' whistle is not rendered properly, so it appears silver instead of gold.
Revealing mistake: Each time when Thomas takes a shortcut, the points do not change.
Revealing mistake: When the elephant is loaded into the truck, the tracks abruptly end behind Charlie.
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.