Harvey is a tank engine with a crane mounted on top of his boiler, which makes him look rather unusual. He is involved in repair, recovery and industrial jobs on the railway .
When Harvey first came to the island, the engines said he looked different and all the engines except Thomas did not trust Harvey, but when he rescued Percy after an accident with some Troublesome Trucks, they realised that his difference was what made him special. Since then, he has proved very useful, using his crane arm for maintenance, building and clearing up. He mainly works at Brendam and the yard, but his favourite place to be is at the Water Works, where he is said to live.