BoCo was built in 1958 at Bowesfield Works in Manchester, England and arrived on Sodor in 1965 to help Edward on his Branch Line. He apparently had a few teething troubles but was fixed by The Fat Controller. One day, he accidentally took Bill and Ben's China Clay Trucks, which made them very angry. They thought he was a "Diseasel", and played a trick on him. They pretended they were one engine and kept going forward and back on opposite tracks to make it seem as if the one engine was quickly changing tracks. This made BoCo very giddy, and he apologized for taking the trucks. He now keeps Bill and Ben in order on the Branch Line.
In an alternate universe 1995, BoCo was going to come with the Breakdown Train from Wellsworth after Gordon was stuck between a sinkhole and a fallen tree, but it was found out the latter wasn't there, nor was the Breakdown train. Henry was instead sent to deal with the predicament. However, he ended up in the accident, as well. A few hours later, both BoCo and James were sent to help clear the accident, and he later dropped both Gordon and Henry off at The Sodor Steamworks.
In June of 2013, BoCo was one of the first engines to encounter Wretch the horrid fuel tanker. Later, he helped with the evacuation of The China Clay Works during the massive flood of August. In March of 2014, BoCo was brought to the Ffarquhar Branch while Thomas was being mended.
The Sudrian Community's model of BoCo was used at first, with the SI3D 2006 model occasionally used if the other didn't work properly. From The Search for Smudger onwards, SI3D's 2012 model was used.
BoCo is based on a BR Class 28. Twenty were built from 1958 to 1959. However, they proved to be problematic due to them suffering from frequent failures, and were all withdrawn from service from December 1967 to September 1969. All were scrapped except for D5705, who is currently preserved on the East Lancashire Railway.
BoCo is one of the friendliest diesels on the island, mostly due to his experience on the mainland. He is very wise and is always willing to lend a helping hand. He is also kind, caring, and hardworking. He is sort of a diesel version of Edward. He shows that not all diesels are bad and that you shouldn't judge a book by its cover.
- A Wretched Day for Henry and James
- Bill and Ben the Brave Brothers of Brendam
- Engine Unknown
- A Tale of a Small Green Engine
- The Runaway Railcar
- The Road Rebel with Rollers (does not speak)
- The Bridge of Caledonian Doom (mentioned)
- Special Engines (does not speak)
- Goatbusters (post credits scene cameo)
- A Tale of Two Small Green Engines (cameo)
- Conspiracy Theories
- How the Diesel Stole Christmas
- The Search for Smudger (part 1 only, cameo)
- Night Express to Vicarstown (does not speak)
- The Most Famous Engine (cameo in part 1)
- Revenge of the Ghost Train
- Tank Engine Mixup (cameo)
- Tommy Davias: Episode I-IV
- KnapfordProductions: How the Diesel Stole Christmas
- Andrew Homer: Episode VII-Revenge of the Ghost Train
- Thomas1Edward2Henry3: Coach Trouble- Season 3 onwards
- Victor Tanzig: NWR Origins
BoCo first appeared in the Season 2 episode The Diseasel. He then appeared in the third and fourth seasons before making his final appearance in the fifth season episode Double Teething Troubles.
- BoCo was the first character to speak in The Engines of Sodor.
- In T1E2H3's RWS, Thomas1Edward2Henry3 gives BoCo a Manchester accent to reflect on where he was built.
- Along with Culdee and Rusty, BoCo was one of the only ERTL models that T1E2H3 owned as a kid.
- BoCo is one of the only major classic characters that hasn't been brought back since the 7th season yet, alongside Duke.
- BoCo has never had a main role in the RWS or TV Series.