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.
Thomas and the Billboard - S12-E1
Revealing mistake: At the beginning of the episode, Henry has Gordon's face.
Audio problem: In the US version (Rusty Helps Peter Sam), Peter Sam has a different whistle sound after the trucks hit him. And throughout the episode, a lot of music and sound effects are missing.
Visible crew/equipment: When Percy passes the Coaling plant, a camera shadow is visible.
Edward, Gordon and Henry - S1-E4
Visible crew/equipment: When The Fat Controller is looking at the goat, a hand is visible in the steam.
Edward, Trevor and the Really Useful Party - S3-E16
Visible crew/equipment: When Bertie is talking to Trevor, in one shot of Trevor, studio equipment is visible in the top left hand corner.
Visible crew/equipment: When Thomas puffs away from Toby, two steam platforms are visible.
Revealing mistake: The old engine's model, who fell off the bridge, was actually Skarloey's, as some red paint can be seen.
Revealing mistake: When the elephant is loaded into the truck, the tracks abruptly end behind Charlie.
Samson at Your Service - S18-E24
Revealing mistake: James is shifted on his body when Samson leaves him.
Visible crew/equipment: When Stepney puffs through the fog after dropping off the stone loads, studio equipment can be seen in the top left corner of the screen.
Visible crew/equipment: When Thomas says to Emily, "Give them back!", studio equipment is visible on the top-right corner of the screen.
Visible crew/equipment: When Henry puffs under the bridge, studio equipment can be seen in the top left corner.
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.
Answer: He was in the water.