Other mistake: Oliver's arm is too tall to fit under the bridge.
Other mistake: Thomas has two side rods when he crashes into the pile of dirt. The duplicated side rod moves even though Thomas' brakes are applied.
Other mistake: In the very first shot of Spencer, his coaches aren't textured.
Other mistake: In the Family Jr. airing, Davey Moore is not credited for writing the episode; Andrew Brenner is. This mistake was fixed in the UK airing.
Other mistake: In the distant shot of Vicarstown, the station is missing its letters.
Other mistake: No shadows are reflected under Percy's flatbeds after his accident with Edward.
Answer: Breakdown trains help the engines back on track.