|Duncan the Rock 'n' Roll Engine|
|Occupation: Skarloey Railway Engine No. 6|
|First Appearance: The Little Old Engine|
|Performer: Tom Stourton (UK/US)|
Duncan is a boisterous, narrow gauge tank engine, who sometimes complains.
Duncan is known as the Rock 'n Roll engine because he will go wherever the mood takes him which usually gets him into trouble with Sir Topham Hatt.