Duke, also known as "The Duke", was the first locomotive of the Mid Sodor Railway company.
Duke was built at Boston Lodge by order of the Duke of Sodor as an engine for the Mid Sodor Railway. In 1947, the line closed and Duke was sheeted and sheltered in the Arlesdale Sheds, as the company was unable to sell him due to his age. He was later rediscovered by Fergus Duncan, the Reverend Teddy Boston and the Reverend W. Awdry in 1969 and then moved to Crovan's Gate, where he was restored and returned to active service in 1983 on the Skarloey Railway.
Awdry built his model of Duke as one of the first locomotives for Ulfstead Road, using the original chassis of the original Albert, a Minitrains 0-4-0. Accrording to Awdry, Duke was still running in 1989, but was struggling. He then built a replacement Duke, who was built on top of an Arnold chassis.
The model was painted like the illustrations, but was named "The Duke" and had the company initials, "M S" on it's tender.