The Fat Controller
Bear (No.D3) was originally known as D7101. He first arrived on the Island of Sodor on a trial for The Fat Controller. He was accompanied by another diesel engine, D199, who talked about taking over the railway, which D7101 didn't like. Later in the same story, D7101 suffered from a failed ejector and had to be rescued by Henry. He befriended his rescuer, and The Fat Controller decided to give him a second chance. D7101 was given a new name, "Bear", a new number, D3, and a new coat of paint, and D199 was sent away in disgrace.