Sidney is a blue diesel engine.
- Sidney is a bit of forgetful diesel, he starts his day on one location, and ends in another, not remembering how he got there!
- Sidney was one of the diesels that laughed at Percy's joke, in Day of the Diesel was seen very dark, it seemed black, but it's blue in pictures.
- Day of the Diesels (not named, laughing cameo)
*He may appear in the seventeenth season in 2013.