Edward, Gordon and Henry - S1-E4
Visible crew/equipment: When Gordon backs on to the siding, you can see the inside of his cab, which is just some equipment.
Edward, Gordon and Henry - S1-E4
Other mistake: When Gordon leaves the station, he has two brake coaches, even though express trains are suppose to have one.
Edward, Gordon and Henry - S1-E4
Other mistake: When Gordon is sent to the siding after breaking down, he passes the set of points needed to cross over to the other line.
Edward, Gordon and Henry - S1-E4
Visible crew/equipment: When The Fat Controller is looking at the goat, a hand is visible in the steam.
Edward, Gordon and Henry - S1-E4
Continuity mistake: When Henry comes out of the tunnel, he's dirty, in the next shot, he's clean.
Edward, Gordon and Henry - S1-E4
Continuity mistake: When the Fat Controller is asking Henry to pull the train, Gordon vanishes.
Edward, Gordon and Henry - S1-E4
Continuity mistake: When Edward is sad, the background behind him disappears between shots.
Edward, Gordon and Henry - S1-E4
Visible crew/equipment: When Edward is pushing the train, you can see a wire inside his four front wheels.
Edward, Gordon and Henry - S1-E4
Revealing mistake: When Gordon passes a signal, the track under him wobbles.
Edward, Gordon and Henry - S1-E4
Visible crew/equipment: In the beginning shot of Gordon leaving the station, studio equipment is reflected off James' tender.
Edward, Gordon and Henry - S1-E4
Continuity mistake: When Edward arrives and tries to push the coaches. In one shot of Gordon on the siding in front of Henry, Gordon's eyes go to his left without moving.
Answer: Breakdown trains help the engines back on track.