The Centre Island Quarry is the quarry where Bill, Ben, and Mavis work and sleep. It was first seen in the sixth season, and has engine sheds, rock hoppers, and large buildings.
As well as mining quarry rock, there is a section of the quarry which mines slate. It replaced Anopha Quarry in the sixth season and then was replaced by the Sodor Slate Quarry in the twelfth season.
Edward has to spend there for a while until Tidmouth Sheds was rebuilt.
The seventeenth season episode, Away From the Sea, states that the Centre Island Quarry is Ffarquhar Quarry. It also appeared in that episode during a flashback.
The set of the Centre Island Quarry
Percy at Centre Island Quarry
shunting at Centre Island Quarry