BoCo is a tame diesel engine, who is sensible, kind and has a decent sense of humour. He is also very disciplined He is a true friend and is often willing to stick up for the underdog.

BoCo is firm, but fair and friendly in his nature, not being afraid to speak his mind.

BoCo upholds a more praiseworthy and respectable, likeable image for diesel engines everywhere, being happy to show the more pompous steam engines that diesels have their uses.