Bear a mixed traffic diesel engine, is so named because of the growling noises he makes.
Bear was originally numbered D7101, and came to Sodor on loan with another diesel named D199. His companion was blatantly arrogant, and bad-mouthed the steam engines. Vulgar noises greeted this, until Duck and D7101 managed to shut up D199.
The next day, 7101's injector failed while pulling the "Limited." Henry, who was already towing D199 and his train of oil tankers, came to help; 7101 was still able to move by himself with some help from Henry. To the passengers' delight, Flying Scotsman took their train, while Henry helped 7101 home. Along the way, Henry told the diesel about his failed regulator. 7101's opinion of steam engines was greatly changed after the incident.
The engines persuaded Sir Topham Hatt to let 7101 stay, and renamed him "Bear." Bear liked this name, saying it meant he "really belonged." Even James, who was the last to accept diesels, could not help but like him. It later was revealed Bear pulls the Express when Gordon, Henry and James are busy. Bear also did Henry's duties while Henry was at the Works.