The No. 6 engine on the North Western Railway, he is a cheeky litttle engine who works on the Ffarquhar Branchline, often pulling the mail. He enjoys playing tricks and teasing the other engines, though this does get him in trouble sometimes
- Season 1: Stepney's Problem, A Scottish Tale, Toby and the New Engine, Duties of the Diesels (cameo), Wilbert to the Rescue, Wilbert and Tiger Moth (cameo), Frank and the Trucks and Gordon Plays a Trick
- Season 2: Daisy and the Visitor (cameo), James' Tender Trouble, A Flying Surprise (does not speak), Twin Trouble (cameo), Old Slow Coach (mentioned), The Flying Scotsman Returns, Save Sir Topham Hatt! and Thomas Helps a Friend
- Season 3:
- Season 4: All For One and One For James, Arthur Helps Out and Rosie's Wild Ride
- Season 5:
- Season 6: Percy's World Record
- Season 7:
- Season 8: Mercy for Percy
- Season 9: Tender Bender.
- Season 10: Bee Yourself, James, Mike Goes on Strike, Coal Crisis (cameo), and Groundhog Gordon.
- Season 11: Big City Rumor, Duncan in the Dumps (cameo), Just Duck's Luck, Spencer Goes Too Far and Holly Jolly Molly.
- Season 12: Greetings, Montague!, Stafford's Electric Slide (cameo), Percy Gets a Promotion, Henry's Handcar Havoc (mentioned), Bulgy Takes the High Road, The Mystery Train (mentioned) and Sidney the Renegade
- Season 13: It's Good To Be Belle (cameo), Victor's Loco Motives, The Duke of Hazard (cameo), Who Stole The Coal?, Ivo Hugh's Day at the Zoo (cameo), Hector and Logan's Hot Pursuit and How Gator Stole Christmas (cameo).
- Season 14: Double-Decker-Wrecker (cameo), Hiro and the Heat Wave, Furious George, S.C.Ruffey's Sweet Tooth (cameo)
- Season 15: For Whom The Belle Tolls, The Island of Misfit Engines.
- Season 16: Henry's Hill, Marion Had a Little Lamb (cameo), Painting the Rosie's Red, Paxman Pulls Through (cameo), Throw Topham from the Train, Ace in the Hole (cameo), Finding Lorry
- Season 17: Unidentified Flying Scotsman (cameo), Bold Slow Coach (cameo), Big Trouble on the Little Western (cameo), Oliver Confusion, Diesel Gets the Bronze (cameo), James and the Giant Screech (cameo), Toby, Or Not Toby, Thomas' Crown Affair (mentioned)
- Season 18: Santa Claws (cameo)
- Percy is one of the four vehicles to be available for Wooden Railway and Wood since 1993 with the others being Thomas, Gordon, and James.