Timothy runs on oil. His naïvety can sometimes lead to the twins playing tricks on him.
Bill and Ben once teased Timothy for being an oil-burning engine instead of a regular coal-burning engine. Timothy started to get upset by this, but ended up having the last laugh when the clay pits ran out of coal.
Sometime later, the twins sent him on a wild goose chase to Brendam Docks to find them a multi-colored truck which they claimed that they wanted for doing something important which was one of their usual tricks, causing Timothy to run around the island on a wild goose chase.
In This Too Shall Pass, after Bill and Ben tricked Donald, Edward told the twins that Marion would be their "chaperone." With one last trick in mind, the tank engines suggested Timothy do the job instead, but Edward quickly recalls the numerous tricks Timothy has fallen for, and stands by his decision to put Marion in charge of the two naughty little engines.
Timothy is very friendly and really wants to be helpful and useful, but he can be a little naïve and gullible, a trait which Bill and Ben love to take advantage of. He is easily scared by loud, sudden noises, but no matter how many tricks they play on him or how much they tease, Timothy just dismisses Bill and Ben as silly engines and gets on with his job. Occasionally, however, his feelings can sometimes be hurt by the twins' tomfoolery. He is also good friends with Marion the steam shovel, and goes to great lengths to help her whenever she needs. While most find Marion's rambling obnoxious, he just thinks she is a funny engine.
- Season 3: Marion Saves the Day (cameo), This Too Shall Pass, Chivalry is Dead (cameo)
- Web Clips: Timothy, Bill, Ben, and Marion - Meet the Characters!
He may appear in Self-Fulfilling Prophecy, as his Meet the Characters! segment was a potential scene from the movie.