BoCo was built in Bowesfield Works in 1963 and was sent to Sodor in 1965 to assist with the goods traffic on Edward's Branch, He was then met by the twins Bill and Ben who had taken there trucks and they played a trick on him which nearly made BoCo eyes pop out! But when Edward told Bill and Ben about BoCo there were abashed and told to fetch BoCo's trucks. He later saved Gordon from the twins teasing and threated to take away the trucks he brought for them and to this day Gordon still thinks that BoCo had saved his life!
When Derek arrived to help on the branch, he broke down on Gordon's hill and BoCo came to the rescue with some workmen to fix him and after that day BoCo and Derek became firm friends ever since!
BoCo is a sensible, kind, wise diesel and is full of a descent amount of humour. He brings good order to the railway and is a respectable, likeable image in front of other Diesels around the island. He is also a versatile locomotive when recognized by The Fat Controller.