Continuity mistake: When Bulgy is driving on the road next to the rails, Thomas can be seen pulling a train instead of being repaired at the foundry.
The Sad Story of Henry - S1-E3
Audio problem: When James is about to puff away from Henry's Tunnel, if you listen closely, James is heard puffing before he has even left. (00:01:00)
Plot hole: When Duck and Diesel leave the shed, Diesel follows Duck instantly, but the tracks they are on both lead to the turntable. As they are on different tracks to each other, it would be impossible for Diesel to follow Duck that quickly as the turntable could only be set to one track at a time.
Continuity mistake: Despite Henry's issue from "Coal" in Season 1 being resolved after the crash in "The Flying Kipper", also in Season 1, Henry needed special coal again from "Thomas and the Magic Railroad" until Season 16.
Bye George - S5-E7
Audio problem: Gordon has Duck's whistle sound before he crashes into the truck.
Visible crew/equipment: As Peter Sam passes Skarloey and Rheneas, a camera shadow is seen.
Other mistake: When Thomas is uncoupled from Annie and Clarabell he has Percy's face.
Character mistake: The narrator says, "some trucks were left behind", but only 1 truck was left behind.
Visible crew/equipment: When Bill runs beside Boco, you can see a camera moving out of the shot. (Visible in HD full screen version).
Visible crew/equipment: In the scene where James pulls up beside Gordon, studio equipment is visible in the top portion of the screen.
Revealing mistake: Salty is missing his rear lamp in the first shot at the docks and a hole is visible where it should be.
Revealing mistake: Dried-up glue is visible around Rusty's face during the line, "Right, we'll find one tomorrow."
Visible crew/equipment: When the Fireflies form the engine, the end of the set is visible in the distance.
Other mistake: At the start Gordon's buffers are crooked.
Springtime for Diesel - S21-E1
Audio problem: Trevor has Stanley's whistle sound when he crosses the level crossing.
Thomas, Percy and the Coal - S2-E1
Visible crew/equipment: In the restored version, studio equipment can be seen when Toby pulls Annie and Clarabel and at the water tower near Tidmouth Station (at the top of the screen in both scenes).
Continuity mistake: Thomas appears to be damaged and dirty after his accident, but he is completely fine and spotless in the final scene. There is no way that Thomas was repaired and cleaned instantly.
Revealing mistake: When Toby asks Thomas if he took on enough water, Toby's eyes are wonky.
Continuity mistake: James and Edward are on the mainline at first, but then they overrun the platform at Dryaw station, which is on Thomas' branch line.
Audio problem: In the 1992 "Thomas Gets Tricked" VHS release, the music stops and a man's voice says, "Look out for the train!" when Thomas climbs up Gordon's Hill. The voice can still be heard in the 1995 release, but the music does not stop.
Answer: Breakdown trains help the engines back on track.