Merlin

Merlin is an experimental tender engine who believes he has the power to turn invisible and has three funnels.

Trivia

 * Merlin's whistle is an LNER A4 3-chime.
 * Merlin's tender is actually a modified version of Bert's.
 * Merlin is the second character to have his basis named in the show, with BoCo being the first.
 * According to Behind the Scenes: Thomas & Friends: Journey Beyond Sodor, Merlin's facial features were based off of his voice actor, Hugh Bonneville.