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.
Character mistake: In the shot of Gordon pulling Percy, he is congratulating Percy, but Percy didn't stop the accident, Gordon himself did. Percy didn't try to get out of the way, Gordon had to put his brakes on as hard as he can. So why is Gordon congratulating Percy?
Character mistake: The narrator says that the passengers covered their ears at the station, but no one is covering their ears, except Sir Topham Hatt.
Answer: Breakdown trains help the engines back on track.