The Runaway - S2-E10
Audio problem: When Thomas is tired and approaching the station, he is moving pretty slow, but the sound of Thomas' wheels moving is like he's going pretty fast.
The Runaway - S2-E10
Visible crew/equipment: When Harold is flying, in one shot, a stage light is reflected off his blades.
The Runaway - S2-E10
Revealing mistake: When Thomas' fireman is ill, you can see a brief flash of red outside, meaning it's James. (Note: same footage from Old Iron).
The Runaway - S2-E10
Visible crew/equipment: When Thomas leaves the station, a tripod is reflected off him.
The Runaway - S2-E10
Revealing mistake: When Duck comes to Terence's field, the end of the track leads right into the bushes right behind duck.
The Runaway - S2-E10
Revealing mistake: When Duck is happy at the beginning, the breakdown train's buffer on the right is broken.
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.