Continuity mistake: Despite Henry's issue from "Coal" in Season 1 being resolved after the crash in "The Flying Kipper", also in Season 1, Henry needed special coal again from "Thomas and the Magic Railroad" until Season 16.
Continuity mistake: Bulgy was converted into a vegetable stand in "Bulgy Rides Again." But from "Excellent Emily" onward, he is a passenger bus again.
Continuity mistake: Throughout Season 4, Henry is painted in two different shades of green.
Revealing mistake: When Thomas collects Rocky, the points are set against him. This also happens when Percy enters the siding.
Plot hole: James appears in every episode before his introduction in "Thomas and the Breakdown Train." Also, James is supposed to be black, because at the end of the episode, James is told he will get a different coat of paint. (He is also black in the book).
Continuity mistake: The engine sheds change design throughout season 1.
Visible crew/equipment: In the shot of Thomas rolling backwards onto the turntable, look left very carefully, and you'll see a camera tripod visible. Fullscreen version only.
Visible crew/equipment: When Gordon, Thomas and the express round the bend, a camera tripod is visible on the left side of the screen.
Continuity mistake: In a close up of Thomas when Gordon is pulling him, Thomas is not coupled up to Gordon's train.
Continuity mistake: When Gordon approaches the station, in the two previous shots, the background changes from a close up of Gordon to a wide shot of Thomas and Gordon.
Continuity mistake: When Gordon says "Yes, I will" the background disappears between shots.
Continuity mistake: In the shot of Thomas stopping inside Knapford with his coaches, Henry is in his new shape.
Visible crew/equipment: When Thomas is on the turntable, a camera shadow is visible on the left.
Plot hole: How could Gordon's driver tell the station master that Gordon couldn't get up the hill? There are no phones on Gordon's hill.
Audio problem: When Gordon backing down to the bottom of the hill, you can hear brakes screeching, but Gordon's wheels are still moving.
Visible crew/equipment: At the beginning, a camera is visible in the top right corner.
Other mistake: Edward is wearing James' sad face mask when he approaches the water column.
The Sad Story of Henry - S1-E3
Audio problem: When James is about to puff away from Henry's Tunnel, if you listen closely, James is heard puffing before he has even left. (00:10:00)
The Sad Story of Henry - S1-E3
Revealing mistake: When the passengers try to pull Henry out of the tunnel, they have putty on their feet. Sir Topham Hatt's hand is also purple.
Edward, Gordon and Henry - S1-E4
Visible crew/equipment: When Gordon backs on to the siding, you can see the inside of his cab, which is just some equipment.
Answer: Breakdown trains help the engines back on track.