Continuity mistake: After Toad avoids James, a works coach moves from in front of the points to behind the points.
Revealing mistake: The rails to the buffers are broken as Toad leaves the siding.
Revealing mistake: When Toad switches lines to avoid Gordon, the track ends in bushes.
Visible crew/equipment: When Toad falls into the pond, in the shot from his point of view, studio equipment can be seen in the top left corner.
Answer: Breakdown trains help the engines back on track.