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.
Continuity mistake: The engine sheds change design throughout season 1.
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.
Edward, Gordon and Henry - S1-E4
Continuity mistake: When Henry comes out of the tunnel, he's dirty, in the next shot, he's clean.
Edward, Gordon and Henry - S1-E4
Continuity mistake: When the Fat Controller is asking Henry to pull the train, Gordon vanishes.
Edward, Gordon and Henry - S1-E4
Continuity mistake: When Edward is sad, the background behind him disappears between shots.
Edward, Gordon and Henry - S1-E4
Continuity mistake: When Edward arrives and tries to push the coaches. In one shot of Gordon on the siding in front of Henry, Gordon's eyes go to his left without moving.
Continuity mistake: When the engines are laughing at Thomas, Henry's eyes are wonky.
Continuity mistake: When Thomas is organizing the trucks, in a second close-up of a truck, the background disappears in mid-sentence.
Continuity mistake: Throughout most of the sequence where Thomas pulls the Troublesome Trucks, the trucks keep changing positions numerous times and many of the trucks disappear and reappear. Also, in a few scenes, there is only 1 truck or just 5 trucks.
Continuity mistake: When Thomas goes through Henry's tunnel, the first van in his train has one bogey. When he comes out, the van has two bogeys.
Continuity mistake: When Thomas leaves Knapford, there is a van in front of the brake van. When Thomas approaches Henry's tunnel, that van disappears.
Continuity mistake: After Thomas organized the trucks, he is facing the trucks, then suddenly he is facing away from the trucks instantly.
Continuity mistake: At the beginning of the episode, the order in the sheds is Henry, Thomas, Gordon, James and Edward. But, when Thomas is complaining, the order is now Thomas, Gordon, James, Edward and Henry.
Continuity mistake: James and Edward are on the mainline at first, but then they overrun the platform at Dryaw station, which is on Thomas' branch line.
Answer: He was in the water.