"Silly" Billy is an Orange Tank Engine with Prominent Buck Teeth.
When we first met Billy, He was Naughty.
Billy is a Manning Wardle L Class 0-6-0ST. Charlie is another Member of This Class.
- Season 4: Duncan and the Passengers
- Season 5: Boastful Billy
- Season 6: Officer Murdoch (does not speak)
- Season 7: Molly's Folly
- Season 8: Tricky Trucks
- Season 9: Tender Bender
- Season 11: Stepney and the Bluebell Branchline (cameo), Station Situation and BoCo and the Cocoa (cameo)
- Season 12: Greetings, Montague! (cameo), The Importance of Being Billy, Percy Gets a Promotion (does not speak) and If The Dome Fits (does not speak)
- Season 14: Millie's Castle Hassle (cameo), Hugo Takes Flight and S.C.Ruffey's Sweet Tooth (cameo)
- Season 15: Roundhouse Roulette and The Island of Misfit Engines
- Season 16: Sweet Sixteen (not named; does not speak), Painting the Rosie's Red, Knock it Off, Stanley and Finding Lorry
- Season 17: Tender Love and Care (does not speak), Toby, Or Not Toby, Rocked by a Hurricane (cameo)