Duncan the Stubborn Narrow Gauge Engine is a supporting character in the television series.
- Season 4 - Gone Fishing
- Season 5 - Accidents will Happen, It's Great to be an Engine, Come for the Ride, and Percy's Seaside Trip
- Season 6 - James the Really Splendid Engine, Little Engines, and Boo! Boo! Choo-Choo!
- Season 7 - The Whistle Song
- Season 9 - Buffer Up and Share, The Work Song, and One Friendly Family
- Season 10 - H is for Harold, Navigation, There's Always Something New, Happy and Sad, and Strength
- Season 11 - The Narrow Gauge Engines
- Season 18 - It's Christmas Time, Jingle Bells!, and We Wish You a Merry Christmas
- The Great Discovery - There's a Job for Everyone, Where, Oh Where is Thomas, and Thomas, You're the Leader
- Although he hasn't had his own music video, Come for the Ride features a section that is dedicated to him.