Timothy loves to work at the China Clay Pits with Bill and Ben, but his naïvete can sometimes lead to the twins playing tricks on him. Despite this, Timothy just dismisses them as silly and gets on with his job.
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. Timothy collected some coal from Brendam Docks and the twins finally apologised for their teasing. Sometime later, the twins sent him on a wild goose chase to find a rainbow-coloured truck, causing Timothy to run around the island until he came across a waste truck covered in paint.
Timothy is friendly, helpful, and loves being really useful, but can also be naïve and gullible.