Visible crew/equipment: As Henry approaches the green signal, the edge of the set is seen in the distance.
James and the Trouble with Trees - S5-E5
Revealing mistake: In the end of the episode, you can see James doesn't have his face fitted on correctly, as the gap between it and his eyes appears to be exposed.
Peter Sam and the Refreshment Lady - S4-E7
Other mistake: In two shots shown at the beginning, Henry is wearing Gordon's upset face mask.
Other mistake: After Toby breaks down, James pushes him directly to Knapford Station, not to the Works as it is said.
Other mistake: When Percy meets Thomas at Elsbridge Station, he has a water line across his boiler, even though the water only came up to his footplate.
Horrid Lorry - S5-E2
Continuity mistake: When Lorry 1 returns after falling into the sea, he is covered in algae and seaweed even though he wasn't submerged. He gains some more of it when Thomas sees him.
Factual error: The dam was built concaved from the water it holds back, but it would have been built convex in order to do so.
Other mistake: Edward is wearing James' sad face mask when he approaches the water column.
A Bad Day for Sir Handel - S4-E6
Revealing mistake: When Sir Handel derails, you can see a small rod sticking up out of the ground from the tracks.
Revealing mistake: When Samson crosses the Vicarstown Bridge, there is no shadow effect on his face.
Revealing mistake: When Gordon falls into the ditch, wires under his cab 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: In a shot of Duck at the smelter's, a hole is visible on his running board.
Gordon Takes a Tumble - S6-E17
Continuity mistake: When Gordon leaves the docks, he has his lamp, but in the next scene, it disappears.
Fergus Breaks the Rules - S7-E18
Continuity mistake: When Fergus runs away, his taillamp is on his right side. When he hides in the siding, his lamp is on the left side.
The Great Little Railway Show - S24-E3
Continuity mistake: In one scene, Rex disappears and is replaced with Mike.
Thomas' Animal Friends - S24-E20
Continuity mistake: When Thomas passes by Crovan's Gate, James' side appears to be silver.
Cleo the Road Engine - S24-E17
Continuity mistake: Thomas' brake van changes design. From a black one, then to an orange one.
Revealing mistake: When Toby tells the Fat Controller about the broken windmill, his driver's head appears to have been digitally added.
Answer: He was in the water.