Duncan is a narrow gauge engine who came to the Skarloey Railway
Duncan came to Sodor as a spare engine after Peter Sam's accident with some of the Troublesome trucks filled with slate. He's also been very cocky, but this has often fired back at him. His driver and fireman spooked him one evening when fireflies formed the shape of an engine. This put Duncan in his place, thinking he had just seen a ghost. His ego once landed him in a swamp, after being careless working on the incline railway.
Duncan is well known and often teased for his temper. He has met his match before, a passenger who grumbled more than him! He also showed a lack of Christmas spirit and often grumbled about the busy work he has to do during that time of year, even going as far to say "Bah Humbug!" Despite his rough exterior, he heroically helped Luke up a hill around Christmas time, showing his kinder side, and was rewarded with a new coat of paint.
A while later, Duncan was at Crovan's Gate when he saw Hugo race by the station surprising him and Sir Handel, who were both wondering if that was an engine.
Duncan is a Scottish narrow gauge engine with rough manners and a strong temper. He was prone to boisterous bouncing about, which became known as "rock 'n' roll", whenever the mood took him, which once led to wedging in the north mouth of Rheneas Tunnel (probably caused from keystones knocked down by his funnel) and derailing on a stretch of line near Cros-ny-Cuirn. While Duncan means well, 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 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, (such as getting in arguments or short lived feuds with Rusty) 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. He is always willing to lend a helping hand whenever he can.
Duncan is based on the Talyllyn Railway's Douglas, an Andrew Barclay "E" or "Light" Class 0-4-0WT. This engine is currently selected to be dressed up as Duncan on special events associated with the "Thomas the Tank Engine" franchise, known as "Duncan Days". Several other engines of this class are also preserved.
In the Railway Series, Duncan is painted in the Skarloey Railway's red livery with blue and yellow lining, and with his name painted on the sides of his boiler in yellow. In the television series, he is painted golden yellow with black lining and gold boiler bands - as of the switch to CGI, however, the lining on his cab is unpainted. He also wears a brass (originally black) nameplate on either side of his boiler, and a black numberplate on each of his coal bunkers.
The Railway Series
- The Little Old Engine - Home at Last, Rock 'n' Roll and Little Old Twins (does not speak)
- Gallant Old Engine - Special Funnel (not seen), Steam Roller (cameo), Passengers and Polish and Gallant Old Engine
- Mountain Engines - Bad Look-Out
- Very Old Engines - Duck and Dukes
- Duke the Lost Engine - Bulldog
- Great Little Engines - Patience is a Virtue, Peter Sam and the Prickly Problem, Pop-Special and Sir Handel Comes Home (cameo)
- New Little Engine - I Name this Engine...
Thomas & Friends
- Series 4 - Bulldog (cameo), Peter Sam and the Refreshment Lady (cameo), Home at Last, Rock 'n' Roll, Special Funnel, Steam Roller (cameo), Passengers and Polish, Gallant Old Engines and Rusty to the Rescue (cameo)
- Series 5 - Duncan Gets Spooked and Snow (cameo)
- Series 6 - Dunkin Duncan and Faulty Whistles
- Series 7 - The Old Bridge (cameo), The Refreshment Lady's Tea Shop (cameo), Rheneas and the Roller Coaster (cameo), The Runaway Elephant, The Grand Opening (cameo), Not So Hasty Puddings (cameo) and Trusty Rusty
- Series 9 - Mighty Mac (cameo), Tuneful Toots, The Magic Lamp, Duncan and the Old Mine and Skarloey the Brave
- Series 10 - Follow that Flour (cameo), A Smooth Ride (does not speak), Duncan Drops a Clanger, Thomas' Tricky Tree, Wharf and Peace and Duncan's Bluff
- Series 11 - Duncan Does it All, Sir Handel in Charge, Cool Truckings and Wash Behind Your Buffers (cameo)
- Series 12 - Mountain Marvel, The Party Surprise (cameo), Duncan and the Hot Air Balloon, The Man in the Hills and Push Me, Pull You
- Series 16 - Don't Bother Victor! (mentioned)
- Series 18 - Duncan and the Grumpy Passenger, Duncan the Humbug and Emily Saves the World
- Series 20 - Saving Time (cameo) and and Engine of the Future
- Series 22 - Counting on Nia (cameo)
- Series 23 - Chucklesome Trucks (stock footage), Diesel Glows Away (cameo) and Diesel Do Right (cameo)
- Series 24 - The Great Little Railway Show (does not speak)
- 2008 - The Great Discovery
- Tom Stourton (UK/US; Eighteenth Season Onwards)
- Ryōichi Tanaka (Japan; Fourth - Seventh Seasons)
- Chikara Osaka (Japan; Ninth Season Onwards, Excluding The Twentieth Season)
- Nobuaki Kanemitsu (Japan; Twentieth Season Only)
- The Reverend W. Awdry's model of Duncan is currently on display at the Narrow Gauge Museum in Tywyn.
- Duncan's large scale model is currently on display at the Hara Model Railway Museum in Japan.
- Duncan's tendency to do "Rock-n-Roll" that resulted in incidents such as scraping tunnels with his cab and derailing were inspired from his real life basis Douglas, who was known for being a "Rough Rider" with its short wheelbase.
- When the Skarloey Railway returned in the sixteenth season, Nitrogen Studios went to the Talyllyn Railway to take measurements of the locomotives to make CGI models of the Skarloey engines. Unfortunately, Duncan's basis, Douglas, was having an overhaul and could not be measured, hence why Duncan did not return in Season 16. When Duncan actually did return in Season 18, he is clearly based on his television model, not his basis, unlike the other engines. Because of this, he is the only narrow gauge engine to have brake pipes or a Talyllyn styled tail lamp.
- Duncan is the only narrow gauge engine whose whistle sound hasn't changed since his debut in the fourth season.
- Michael Angelis, George Carlin, Michael Brandon, Pierce Brosnan and Tom Stourton all give Duncan a Scottish accent; reflecting his basis' origins.
- Season 4
- Duncan's Angry Smile Face Mask for his Small Scale Model
- Duncan's happy face mask for his small scale model (used in the fourth and fifth seasons) is now owned by Twitter user Thomas Merchandise.
- In the Latin American dub, Duncan had a German accent between the ninth and eleventh seasons.
- Duncan has had several modifications over the series. These include:
- Series 5 (large scale model only):
- The wrinkles on his forehead disappeared, his eyes and nose became slightly larger, his eyebrows became slightly thicker and he lost the cleft in his chin.
- His buffers became silver and his buffer housing changed shape from square to round.
- His cab windows became larger.
- His running board becomes thicker.
- Series 6:
- His silver buffers became black.
- He gained a visible whistle.
- His cab windows and running board returned to how they were in the fourth season.
- Series 9:
- Added tail lamp.
- Season 17 Duncan's Cameo Is in The Switch and Luke's New Friend
- Series 18:
- Smaller in size than both his original model and his basis.
- Red running board.
- Permanent lamp, lamp irons, brakepipes and outlets.
- Slightly thinner funnel.
- Slightly smaller dome and windows.
- Smaller boiler and coal bunkers.
- The brass pipe conecting to his dome became thinner.
- Brass nameplates.
- Shorter and wider sand dome.
- Sanding gear under the cab.
- Riveting under his coal bunker and on his smokebox.
- His coupling hooks gained a grey base with bolts.
- His buffer housings shape changed back to square
- The lining on his cab and bunkers became outdented and unpainted
- His cutout windows gained frames and glass.
- His eyes, eyebrows, nose and chin returned to how they were in the fourth season.
- Series 5 (large scale model only):