Duncan works on Mr. Percival's narrow gauge railway. He means well but will "Rock and Roll" along the rails whenever the mood takes him. Duncan has a great big heart but is a little misguided.
Duncan was built by Andrew Barclay at Kilmarnock, Scotland and worked in a factory in Scotland, which Peter Sam claims is the source of his strong language and volatile temper. In 1957, Duncan was bought secondhand to Sodor as a spare engine, as the workload was too much for Sir Handel and Peter Sam to manage unassisted.
He was still selfish and prone to temper tantrums and actually stalled on Rheneas Viaduct on the claims that he was overworked and not polished enough. Skarloey, fed up with his careless attitude, finally taught him sense with the story of Rheneas' single handed running of the railway and how passengers are far more important than a polish.
Duncan is an often tempermental and careless engine, but over the years has grown up to become far more responsible and hard working. His infamous "rock and roll" phase was brought about partly by his short 0-4-0 wheelbase, which caused him to ride roughly at high speeds. He is quite a powerful worker despite his size. His persona as introduced in the fourth season was consistent with his early book appearances.
Since the sixth season, Duncan is quite often bossy to the other engines about getting their work done quickly and thinks he knows better than them. Duncan still seems to ignore Rusty's warnings and advice until he lands himself into trouble. Also, Duncan tries to do the jobs which he thinks suits him well and he is quite competitive with James.
Basis EditDuncan is based on the Talyllyn Railway's Douglas, not to be confused with the standard gauge engine Douglas. This engine is currently selected to be dressed up as Duncan on special events associated with the "Thomas the Tank Engine" franchise.
- Duncan is the tallest of the narrow gauge engines.
- Duncan is currently visiting the Talyllyn Railway in Wales as a tourist attraction and is currently being overhauled. Sir Handel has been brought in to do Duncan's work until he is mended.