Dexter is a Oigawa Railway Thomas who works on the Railway Exhibition.
Dexter 1st appeared on Fergus' Online Store Finds 7, where Fergus unboxed him. At the end of the video, though, Thomas came up and welcomed him, saying that he's gonna be known as an engine called "Dexter". He got a role as the main protagonist in Island Tales Episode 10: Tourist Train Troubles. After that, he has been appearing with either a small role or a cameo.