Billy

Billy is a small orange tank engine with noticeably buck teeth. In Don't be Silly Billy when he first arrived, The Fat Controller asked Thomas to show him the right way to do things, but he thought Thomas was being bossy. He runs off and then runs out of coal and water, Thomas helps him to a station and after that, he doesn't think Thomas is bossy. Billy is the sixth engine to pull Annie and Clarabel.

Billy resembles a GWR Class 1361 0-6-0ST.