"She bought it! Heh heh heh!"
— Fergus, after he tricked Molly, Fergus' Day Off, eleventh season Fergus is a traction engine. His catchphrase is "do it right" and always says it when an engine is doing something wrong.
- Season 1: A Scottish Tale, Wilbert and Tigermoth (cameo), Frank and the Trucks (cameo), and Thomas’ 4th of July (cameo)
- Season 5: Fergus' Market Day
- Season 6: Rosie Being Lazy
- Season 9: Arthur and the Fights of the Brown Turntable
- Season 10: Scruff and S.C. Ruffey and Mike Goes on Strike (cameo)
- Season 11: Fergus' Day Off, Stepney and the Bluebell Branchline (cameo), Station Situation and Old Square Wheels
- Season 12: Greetings, Montague!, Scottish Blues (cameo) and Henry's Handcar Havoc (cameo)
- Season 13: Who Stole the Coal? (cameo)
- Season 14: Cabless Companions
- Season 15: Roundhouse Roulette (does not speak)
- Season 16 Painting the Rosie's Red (cameo) and Victor and Victoria (cameo)
- Season 17: Oliver Confusion (cameo), Rocked by a Hurricane (cameo) and Para-Norman Activity (cameo)
- Season 18: Patrick Cements His Legacy
Specials: Oliver's Eleven
Fergus is based on a real traction engine previously named "Blue Circle" which is the same color as Fergus. On occasions, "Blue Circle" has been dressed up as Fergus.