Clark is a GWR 1361 Class Tank Engine owned by the Dock Railway. During Clark's service on the Great Western Railway, he was involved in a serious crash with a slow goods train. He wasn't badly damaged, but he suffered serious brain damage and was left mentally retarded (And to a lesser extent, his right Cylinder case was dented). He was disowned by the GWR shortly afterwards after he caused several more accidents, but he was bought by an owner of a small heritage railway in Barrow. He was then traded among several minor railway companies in the U.K. until the Modernization plan took action. He was bought cheap by Casey Jones, then desperate for new engines to help with the increased traffic. He is still a hassle, but has since improved since joining the Dock Railway. He often breaks down, but Jaimie, who has taken the duty of being a father-figure to him, keeps a close eye on him and always gives him a hand when he breaks down. In 2011, he became the Southern Pacific "Bloody Nose" heritage engine, and he was repaired finally. He also became smart.
Clark was painted GWR green with red lining until 2011, were he got re-painted into the Southern Pacific "Bloody Nose" heritage scheme.