Revealing mistake: When Toby asks Thomas if he took on enough water, Toby's eyes are wonky.
Continuity mistake: When Emily and Whiff pull the rubbish trucks away, Whiff is coupled up to Emily, and Emily is coupled up to the trucks. When they pull them away, their buffers are separate.
Character mistake: Black smoke comes out of Thomas' funnel 50 seconds before the narrator says so. (00:03:40)
Visible crew/equipment: When Thomas puffs away from Toby, two steam platforms are visible.
Revealing mistake: When Henry arrives at the forest where he finds his lucky trucks, one of the trees is not covered in snow.
Audio problem: At the beginning of the episode, Gordon has Edward's whistle sound.
Continuity mistake: The children waving at Toby disappear after Toby puffs under the bridge.
Continuity mistake: Alicia Botti was annoyed by Toby's appearance. But in "Thomas, Percy, and the Squeak", she thought Percy being dirty was the proper appearance of a steam engine.
Gordon and the Engineer - S11-E6
Continuity mistake: When Gordon is at the signal box, he drops off his coaches on his track and leaves. When he comes back with the mechanic, the coaches are gone.
Thomas and the Runaway Car - S11-E17
Visible crew/equipment: When the flatbed rolls away from Thomas, you can see a finger of a crew member in the bottom corner.
Answer: Breakdown trains help the engines back on track.