Thirteen

   13 The Unlucky Engine   
 * Number: 13

Bio
13 is a black saddle tank engine with an open cab from the Mainland who appeared in a story called "The Unlucky Engine" in a "Thomas and Friends" magazine. He is very unlucky, and when he first arrived he caused trouble for Donald and Douglas, had his firebox damaged and stuck in a landslide. The Fat Controller sent him to the Works, and although Donald and Douglas thought that would be the end of him, he came back with a bigger firebox, which cured his unluckiness. After his repairs, 13 told Donald and Douglas that he came to the Island of Sodor as an unlucky engine, but going back to the Mainland as a very lucky engine.

Number
13's number is fitting, as the number 13 is infamous for being unlucky.

Livery
13 is a black saddle tank engine with red stripes and has a red 13 painted on each side of his saddle tank upon a yellow background with a red stripe around his numbers.

Basis
13 is a small tank engine with (presumably) a 0-4-2 wheel arrangement. As 13 took Donald and Douglas's trains back to where they came, he is a standard gauge engine - though he bears the resemblance of Peter Sam/Stuart.

Trivia
13 is the fourth engine to have a number for a name. The first three are 98462 and 87546 and Sixteen.