Continuity mistake: During the chase scene at the end of the film, P. T. Boomer (a character cut from the film), can be seen on top of Diesel 10 during the shot where he enters a tunnel.
Visible crew/equipment: In the shot where Diesel 10 races past Thomas and Gordon near the beginning, you can see a black pencil on the right of the screen.
Other mistake: The end credits show Annie, Clarabel, Bertie and Harold under the voice cast for "the trains", but Annie and Clarabel are rolling stock, Bertie is a road vehicle, and Harold is an aircraft, respectively.
Continuity mistake: James' whistle disappears when Diesel 10 appears at the Smelter's yard.
Other mistake: When Billy Twofeathers says, "Does Burnett Stone ever give you a smile?", a fly can briefly be seen.
Continuity mistake: When Diesel 10 is hanging, he's vertical. But in the next shot, he falls horizontally.
Revealing mistake: When Diesel 10 stops in front of James at the smelters, the mechanism used to power Pinchy can be seen through his vents.
Revealing mistake: When Mr. Conductor gets his gold dust back, the green screen effects are partially visible.
Continuity mistake: After Diesel 10 is covered in coal, Henry is next to Gordon, then suddenly next to Splatter and Dodge.
Continuity mistake: After Thomas collects the coal truck and Lily praises him, it briefly vanishes from behind him.
Revealing mistake: In a close-up of Thomas' wheels during the chase scene, they appear to be damaged.
Visible crew/equipment: When Thomas follows Diesel 10 from the sheds, the end of the set is visible.
Other mistake: In a shot of Percy at night, James' tender is derailed.
Continuity mistake: After Thomas crosses over the collapsing viaduct, his steam disappears too quickly.
Revealing mistake: As Diesel 10 leaves after overhearing Thomas and Percy, a red wire can be seen in his cab.
Revealing mistake: As Thomas crosses the viaduct gap, a rope can be seen pulling him.
Revealing mistake: In Thomas' first appearance, he has no cab doors. He continues to not have cab doors throughout the movie except for a few shots.
