Continuity mistake: In a close up of the tar wagons before James crashes into them, James disappears.
Visible crew/equipment: When James crashes into the tar wagons, a finger can be seen in the bottom right-hand corner.
Character mistake: The narrator says that James ran into two tar wagons, but he ran into four. Two is the amount of tar wagons that derailed.
Continuity mistake: James leaves Elsbridge Station with the brake coach at the rear. When James arrives at Knapford Station, the brake coach is in the middle.
Other mistake: James passes a green signal, but there are tar wagons ahead.
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.