The Sad Story of Henry - S1-E3
Revealing mistake: When the passengers try to pull Henry out of the tunnel, they have putty on their feet. Sir Topham Hatt's hand is also purple.
Continuity mistake: When James passes Edward at Knapford, Edward's train does not have a brake van. But two shots later, it does.
Audio problem: When Arthur arrives at the lake, he has Spencer's whistle.
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.
Lady Hatt's Birthday Party - S5-E4
Continuity mistake: When George crashes, the Fat Controller falls into the ditch head first, but in the following shot he is sinking feet first.
Continuity mistake: The sign says: "Danger - engines must not pass this board." When Thomas passes it, "board" is replaced with "point."
Revealing mistake: In a shot of 2 vans singing "Pop Goes Old Ollie" you can see a spider crawling on the right side of the left van in the screen.
Visible crew/equipment: When Bill runs beside Boco, you can see a camera moving out of the shot. (Visible in HD full screen version).
Thomas and the Missing Christmas Tree - S2-E26
Visible crew/equipment: In the scene of Donald and Douglas going out of the yard, a camera tripod can be seen in the top left corner.
Thomas and the Breakdown Train - S1-E7
Revealing mistake: In the scene of James' wheels sparking while passing Tidmouth Sheds, a metal rod is igniting the sparks from his wheels.
Visible crew/equipment: As Henry crashes into the goods train, a crew member's hand can be seen pushing him, at the left side of the screen.
Revealing mistake: Max's wheels can be seen moving backwards when he is actually driving forwards. Also, both Max and Monty's steering and wheel speeds are out of sync with their movements. These events happen throughout the episode.
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).
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.
Factual error: A "wonky" whistle doesn't sound like a slide whistle, it should sound like a weakened version of the correct whistle mixed with the hissing sound of steam. A "wonky" whistle would also leak steam constantly instead of being blown like a normal whistle.
Continuity mistake: When Thomas is organizing the trucks, in a second close-up of a truck, the background disappears in mid-sentence.
Thomas, Percy and the Squeak - S6-E21
Other mistake: When Thomas sees Percy at the washdown, Gordon's front and rear bogie wheels are derailed.
Santa's Little Engine - S17-E18
Revealing mistake: At one point, the shading effect on Thomas' whistle is not rendered properly, so it appears silver instead of gold.
Lady Hatt's Birthday Party - S5-E4
Continuity mistake: When George drives into the ditch, the Fat Controller prematurely tips over, then tips over again in a closeup shot.
Answer: He was in the water.