Harvey is a maroon tank engine with a crane mounted on top of his boiler, which makes him look rather unusual.
Harvey is a big-hearted and relentlessly cheerful crane engine. With his booming voice and unusual shape, Harvey is always ready to help clean up after any crash. He's happy working in the yards, the Docks and building sites, but his true home is at the 'Sodor Water Works' 
Harvey came to Sodor on a rough patch. Before giving a demonstration to earn his place on the railway, he was hurt by the other engines' unkind comments about his strange boiler crane arm. But when Percy had a derailment, Harvey made quick work in clearing up the wreckage and making a good enough impression to stay on Sodor.
He is a kind, tough engine used for smaller jobs that his arm is best suited for and makes short work of any task he is given.
Harvey is a kind, friendly and hardworking crane engine. He enjoys helping out when his friends are in distress.
Harvey is based on Dubs Crane Engine No. 4101, nicknamed "Dubsy".
- In the twelfth series episode Saved You!, Harvey appeared without a CGI face. However, a magazine had two images from this episode showing Harvey with one.
- Harvey occasionally has a bucket or claw attached to his crane arm so that he can pick up coal and other minerals.