- "I shall never forget Sodor because this is the place where my bad luck turned good!"
- ―Thirteen to Donald and Douglas, The Unlucky Engine[src]
Thirteen is a black saddletank engine from the Mainland, who once had an open cab.
Thirteen was a spare engine from the Mainland and was brought to help Donald and Douglas, who were feeling overworked. When he first arrived, he proved to be very unlucky. He caused delays for Donald and Douglas, got hit by a land-slide, and then damaged his firebox which got knocked out of place. Sir Topham Hatt sent him to the Works, and Donald and Douglas thought that would be the end of him.
However, after his repairs he came back to Sodor with a bigger firebox and a proper cab which cured his unluckiness. He told Donald and Douglas that he came to Sodor as an unlucky engine, but returned to the Mainland as a very lucky one. It is unknown what happened to him afterwards.
Thirteen was a rather unlucky engine. Despite his unluckiness, he did his best to help out Donald and Douglas. Although his bad luck soon gets the better of him and the twins. After his repairs, he had a bigger firebox which cured his unluckiness, and he returned to the Mainland as a very lucky engine.
Unlike most engines, Thirteen's basis is unknown. He is a standard gauge engine, though he looks more like a narrow gauge engine. He may be a freelance design.
Thirteen is painted black with red lining. He has a red and yellow numberplate with the number "13" he is named after painted on each side of his saddletank. Unlike most engines, his running board is also painted red.
- His name originates from the superstition that the number 13 is unlucky.