Revealing mistake: While the passengers are evacuating the station, the platform moves, a pillar in the background moves, and putty can be seen on the platform (stains of it) and on some passengers' feet.
Audio problem: In the extended Season 19 version of "Engine Roll Call," Henry's whistle sound is out of place as it can be heard during Emily's part of the song. Also, Henry is not mentioned in the Season 22 version of the song, but his whistle sound can still be heard.
Thomas, Percy and the Squeak - S6-E21
Continuity mistake: When Percy arrives at Brendam, his steam platform is visible and some of the steam from his funnel disappears, indicating a film cut.
Thomas, Percy and the Squeak - S6-E21
Other mistake: When Alicia the mouse is inside Clarabel, she is missing her forepaws.
Thomas, Percy and the Squeak - S6-E21
Visible crew/equipment: When Thomas arrives, his steam platform is visible.
Continuity mistake: Before Percy Runs Away, his crew is out of the cab. But after Percy Runs Away from Gordon, his crew is back in the cab.
Continuity mistake: In a close up of the tar wagons before James crashes into them, James disappears.
Visible crew/equipment: When James crashes into the tar wagons, a crew member's finger can be seen pushing him.
Character mistake: The narrator says that James ran into two tar wagons, but he ran into four. Two is the amount of tar wagons that derailed.
Continuity mistake: James leaves Elsbridge Station with the brake coach at the rear. When James arrives at Knapford Station, the brake coach is in the middle.
Other mistake: James passes a green signal, but there are tar wagons ahead.
The Christmas Coffeepot - S20-E12
Audio problem: When Glynn says "Oh dear!" his mouth doesn't move.
The Christmas Coffeepot - S20-E12
Audio problem: In the US version, Glynn says "Oh, what? What? Ooh, it's you again..." but in the UK version, the line is omitted. As a result, his eyes move as he is saying something. However, the line is not absent on most UK versions of the episode on YouTube.
Continuity mistake: When Henry sneezes at the boys, you can see that the boys got ashes on them before the smoke has even touched them yet.
Revealing mistake: Most of the engines' eyes are wonky when Diesel says their names and their eyes are wonky in a few shots of them.
The Afternoon Tea Express - S17-E26
Continuity mistake: In the shot of Stephen at the dairy, one of the trucks is in the front and the other one is at the back. But in the shot when Stephen is out and about, the first one is at the far back and the other truck is at the front, but later, the trucks go back to their original positions.
Continuity mistake: After Thomas goes to the docks, the giraffe's flatbed somehow changes tracks at the Animal Park.
Continuity mistake: When Thomas finds Percy, he is behind him; but later when they arrive at the Steamworks, Thomas is in front. The same thing happens with Edward.
Other mistake: The narrator says that Thomas' driver puts syrup in the lion, but actually, Thomas fireman puts the syrup on the lion. This is identified by his moustache.
Revealing mistake: Some of the team members of the football team are duplicated.
Answer: He was in the water.