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 1958, 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 came soon after Peter Sam's accident with the slate trucks and was re-gauged to 2ft 3in. Duncan was rude and arrogant at first. However, following derailments in the tunnel and on a stretch of track south of Cros-ny-Cuirn, he began to see sense and made up his feud with Rusty, whom he had detested for being a Diesel.
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 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.
Duncan initially arrived to the Skarloey Railway as a spare engine after Peter Sam had a nasty accident with some trucks that broke free from the incline. He was prone to boisterous bouncing about, which became known as "rock 'n' roll", whenever the mood took him, which once caused him to derail in the mouth of a tunnel. He speaks with a Scottish accent and is a rather tall engine. He often grumbles and complains, usually about not being polished or being over-worked, and can be rude, rough, and bad tempered. He claims to be a plain-speaking engine who believes in plain speaking, an approach which can cause him to make callous or belligerent remarks. Duncan can be a competitive engine too, particularly with James. He can be careless and make rash decisions which usually leads to his own downfall, but is not always quick to apologise or realise the error of his ways. However, upon Skarloey recalling Rheneas' gallant act to get his passengers home, Duncan admitted he had the wrong attitude and tried hard to be a more useful, respectable engine in future. In spite of his ways, Duncan can be a little misunderstood as he is focused, confident, resourceful, and has a big heart.
In the Railway Series, Duncan is painted in the Skarloey Railway's red livery with blue-and-yellow lining. In the television series he is painted yellow with black and gold lining.
- One of Duncan's models is currently on display in Japan.
- In the ninth season, Duncan gained a tail lamp.
- Duncan's was called Dominique in the French narration of the Classic Series.
- ERTL (normal and metallic; discontinued)
- Wooden Railway (discontinued)
- Take-Along (discontinued)
- Motor Road and Rail (discontinued)
- TrackMaster (normal, Duncan Does it All, and The Runaway Elephant versions)
- My Thomas Story Library (discontinued)
- Bandai Tecs (several versions; discontinued)
- Trading Cards (discontinued)
- De Agostini
- Brio (discontinued)
- Nakayoshi (discontinued)
- Wind-up (normal and metallic)
|Skarloey • Rheneas • Sir Handel • Peter Sam • Rusty • Duncan • Ivo Hugh • Duke • Fred • Mark V • Ministry of Defence Engine|
|Bertram • Mighty Mac • Freddie • Luke • Proteus|