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 left 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: When Diesel 10 is hanging, he's vertical. But in the next shot, he falls horizontally.
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.
Continuity mistake: James' whistle disappears when Diesel 10 appears at the Smelter's yard.
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.
