Terence is a crawler tractor, who works near Thomas' Branch Line. He is owned by Farmer Finney.
When they first met, Thomas insulted Terence for having caterpillar tracks, but regretted it after Terence pulled him from a snowdrift.
In the twenty-first season, Terence took a shortcut over a frozen lake while collecting Christmas trees for the holiday market, but in the process the ice began to break. While Thomas did rescue Terence, the Christmas tree was lost
Terence is an assertive, orange tractor with caterpillar tracks. The engines find these very unusual, but Terence is very capable of proving that he does not need rails and that his tracks allow him to go practically anywhere. He takes any teasing in the name of fun and is happy to get on with his job, usually partaking in agricultural work. Terence never hesitates to assist in emergencies or sticky situations, road or rail, due to his helpful, forgiving nature. His tracks are particularly invaluable in harsh winter conditions when snow can affect transport across the Island. He may be slow, but he is versatile, adaptable, and helpful. He can usually be found transporting agricultural produce or cheerily ploughing fields beside Thomas's branch line.
Terence is based on a vintage Caterpillar Model Seventy - the largest, and last, design of petrol-powered tractors in Caterpillar's range.
Terence is painted orange with grey caterpillars and a black engine and exhaust pipe.
- Season 21 - Terence Breaks the Ice
- Terence has a detachable plough.
- According to a magazine article, he sometimes works on Farmer Trotter's Pig Farm.
- In some merchandising and books, Terence's name is sometimes misspelt as "Terrence".
- Terence's French name was Thierry in the Classic Series.
- He was only ever shown with two face masks in the television series, both of which were smiling, though he was illustrated with a wider variety of expressions in the Railway Series, annuals, and magazine stories.
- Up until Season 21, Terence never had any eyebrows in the television series, although he is shown to have eyebrows in some illustrations and merchandise.
- In the twenty-first season, Terence's widow's peak is replaced by his eyebrows. His face also became more elongated, covering his entire front, and it is missing the small indents it originally had.