|First Appearance||Rickety's Ridiculous Ruckus (Cameo)|
|Basis||Prince (a tender engine from the Ffestiniog Railway)|
|Livery||Brown with yellow lining|
|Voice Actor|| mambisdpambis
A long time ago, Duke worked on the Mid-Sodor Narrow Gauge Railway with Falcon, Stuart, Bertram, and Smudger. Despite the fact that Duke was very old, he almost never failed in his work and proved his worth many times. They worked happily together for many years (despite the fact that Smudger was turned into a generator) until their line was closed down. Stuart, Falcon, and Bertram were sold to the Skarloey Railway, and Duke was left alone in his shed.
Years later, Sir Topham Hatt and friends were hiking when Sir Topham stumbled and fell through Duke's shed's roof. The team rescued Duke and brought him to the Skarloey line, where he was reunited with Stuart and Falcon, now known as Peter Sam and Sir Handel, as well as Bertram. Rumor has it that Smudger's remains (behind Duke's shed) were also recovered and rebuilt under Sir Topham Hatt's orders. However, those rumors have been neither confirmed nor denied. Duke later became friends with all the other Narrow Gauge engines, such as Skarloey, Luke, and Rusty.
In recent days, Duke has been complaining about aching pains, and it was discovered that he was falling apart at the seams. He was given an overhaul, and when he returned, he was assigned to work at the Blue Mountain Quarry with all of his fellow Narrow Gauge Engines. Duke was recently involved in an accident with Ivo Hugh's runaway slate train, and was forced to be sent to the Works once again.
Duke is one of the oldest and most experienced engines on the Narrow Gauge Railway. He is wise and compassionate. Many of the Narrow Gauge engines, including Sir Handel, Peter Sam, and Bertram, consider Duke their mentor. He is keen to uphold his name's legacy, saying "That would never suit His Grace" when something goes wrong on the railway due to the carelessness of another engine. Many engines have grown fond of Duke and he is affectionately known as "Granpuff" among the engines.