Montague (nicknamed Duck) is a tank engine from the Great Western Railway.
Duck worked at Paddington before moving to Sodor in 1955 to take over Percy's shunting duties, leaving the latter free to assist with the construction of Knapford Harbour. Duck was a hard worker, but the others mistook his work ethic for simplicity and tried to use this to their advantage. They soon found their mistake when Duck and Percy took revenge on them by barring them from the shed. Duck earned a reprimand from the Fat Controller for this.