Continuity mistake: Gordon can be seen next to Edward when Edward says "two big engines afraid of a cow?", but Gordon should have been on the turntable.
Revealing mistake: Edward has wonky eyes in some scenes.
Other mistake: The episode's title in the original PBS Broadcast version is "The Old Iron Bridge" but the bridge was made of wood.
Thomas, Percy and the Coal - S2-E1
Revealing mistake: In some shots of Thomas and Percy, both engines have wonky eyes.
Thomas, Percy and the Coal - S2-E1
Revealing mistake: When Toby pulls Annie and Clarabel, the latter coach has a loose roof.
Thomas, Percy and the Coal - S2-E1
Continuity mistake: When Thomas is being covered in coal, he is dirty in some shots, but in other shots he is clean.
Revealing mistake: Each time when Thomas takes a shortcut, the points do not change.
Factual error: When Bertie finds Thomas derailed, Bertie is on the wrong side of the road. The UK drives on the left. Also, Thomas runs under North American directional rules at the beginning and end of the episode.
Character mistake: UK Only: When Thomas comes back to Annie and Clarabel, he calls the latter "Carabel."
Continuity mistake: Gordon's connecting rods change position after he pulls Thomas out of the mine.
Character mistake: Black smoke comes out of Thomas' funnel 50 seconds before the narrator says so. (00:03:40)
Character mistake: In the trivia game on the "On Site With Thomas" DVD, Monty's name is misspelled as "Monte."
Factual error: In the "Steamie or Diesel" game on the "All Aboard with the Steam Team" DVD, Spencer is incorrectly called a diesel even though he is a steamie. Whenever you get the wrong button, Spencer says he actually has a horn instead of a whistle and even says he is a diesel engine.
Wrong Road - S2-E22
Revealing mistake: When Gordon says, "I am Gordon! Stop! Stop!", his eyes are wonky.
Thomas and the Billboard - S12-E1
Revealing mistake: At the beginning of the episode, Henry has Gordon's face.
Visible crew/equipment: When Diesel is on the turntable, camera equipment is reflected in the windows for several moments. (00:02:00 - 00:10:00)
Visible crew/equipment: When Bill and Ben are shunting, we can see hands. (00:02:00 - 00:10:00)
Thomas and the Billboard - S12-E1
Other mistake: In the opening scene when Edward and Henry can be seen going into Knapford, Henry is wearing Gordon's face mask.
Other mistake: When James crashes into the tar wagons, Sticky Tac can be seen on his tender.
Thomas and Percy's Christmas Adventure - S3-E26
Audio problem: When this episode was re-narrated in the US, it was changed to an episode about Thanksgiving. This caused a scene to get cut, which messed up the dubbing track, making half of the episode out of sync. (00:03:00)
Answer: Breakdown trains help the engines back on track.