Thomas, Terence and the Snow - S1-E13
Revealing mistake: When Thomas gets dragged out of the snow by Terence, he is still covered in snow all around him, but two shots later, the snow has vanished.

Starring: Alec Baldwin, Michael Brandon, Ben Small, Martin Sherman, Michael Angelis
Thomas, Terence and the Snow - S1-E13
Revealing mistake: When Thomas gets dragged out of the snow by Terence, he is still covered in snow all around him, but two shots later, the snow has vanished.
Plot hole: When Duck and Diesel leave the shed, Diesel follows Duck instantly, but the tracks they are on both lead to the turntable. As they are on different tracks to each other, it would be impossible for Diesel to follow Duck that quickly as the turntable could only be set to one track at a time.
Thomas: Wake up lazy bones - do some hard work for a change.
Trivia: The events of this episode were remade in CGI for the 2015 special, The Adventure Begins.
Question: How did they get the broken down train at the scene of the crash without any calls?
Answer: Breakdown trains help the engines back on track.