Other mistake: The Rev. W. Awdry is not credited in the title card of the episodes "Mike's Whistle", "Tit for Tat", and "Useful Railway." Only Andrew Brenner's name appears.
Revealing mistake: The end of the set is visible in one shot at the quarry.
Henry Gets the Express - S20-E3
Continuity mistake: Throughout the scene when he is at Brendam Docks, Gordon's paintwork is noticeably darker.
Diesel and the Ducklings - S20-E4
Continuity mistake: When Diesel keeps James and Gordon waiting, they are at the top of the hill, but a few shots later, they are at the bottom of the hill.
Bradford the Brake Van - S20-E5
Other mistake: A rock is floating in mid-air when Thomas goes up Gordon's Hill.
Other mistake: Duck stops at Arlesburgh West Station for 5 seconds, which is not enough time to let passengers board his train.
Continuity mistake: When James passes Edward at Knapford, Edward's train does not have a brake van. But two shots later, it does.
The Christmas Coffeepot - S20-E12
Audio problem: When Glynn says "Oh dear!" his mouth doesn't move.
The Christmas Coffeepot - S20-E12
Audio problem: In the US version, Glynn says "Oh, what? What? Ooh, it's you again..." but in the UK version, the line is omitted. As a result, his eyes move as he is saying something. However, the line is not absent on most UK versions of the episode on YouTube.
Revealing mistake: When Samson crosses the Vicarstown Bridge, there is no shadow effect on his face.
Continuity mistake: Sir Handel was just near the turntable when Samson approaches the Blue Mountain Quarry, but a few shots later, Sir Handel has moved to a siding.
Continuity mistake: Thomas appears to be damaged and dirty after his accident but in the final scene, he is undamaged and clean.
Revealing mistake: Max's wheels can be seen moving backwards when he is actually driving forwards. Also, both Max and Monty's steering and wheel speeds are out of sync with their movements. These events happen throughout the episode.
Other mistake: Oliver's arm is too tall to fit under the bridge.
Other mistake: Thomas has two side rods when he crashes into the pile of dirt. The duplicated side rod moves even though Thomas' brakes are applied.
Other mistake: In the very first shot of Spencer, his coaches aren't textured.
Factual error: At the beginning of the episode, the narrator says that Connor and Caitlin are faster than Spencer, but Spencer, an LNER A4, holds the world speed record for steam locomotives.
Other mistake: In the Family Jr. airing, Davey Moore is not credited for writing the episode; Andrew Brenner is. This mistake was fixed in the UK airing.
Audio problem: After Rex is hoisted back on the rails, Mike has Rex's whistle sound.
Answer: He was in the water.