— Donald and Douglas' line whenever something goes wrong
Donald and Douglas are twin Scottish tender engines.
- Season 1: A Scottish Tale, Frank and the Trucks (Donald or Douglas cameo) and Gordon Plays a Trick (Donald or Douglas cameo)
- Season 2: A Special Visitor (Douglas only, cameo), Daisy and The Visitor (Donald or Douglas cameo), James' Tender Trouble (Donald only), The Flying Scotsman Returns (Donald or Douglas) and The Flying Scotsman Departs (cameo)
- Season 3: Double Trouble (Douglas only, cameo), Hideous Henry (do not speak), George the Steamroller, Diesel's Dilemma (Donald only), New Engine Fever and Donald Visits The Scrapyard (Donald only),
- Season 4: The Unseen Diesels, Rosie's Wild Ride (Douglas only) and Naughty Engines (Donald only)
- Season 5: Snow Can't Stop Us (cameo)
- Season 6: Officer Murdoch
- Season 7: Molly's Folly (Douglas only), The End of The Track, Stanley and the School Trip and Terence's Train (Donald does not speak)
- Season 8: Tick-Tock-Jock (Douglas only), Frank and the Fib (Donald only) and The New Controller (Donald or Douglas cameo),
- Season 9: Hankenstein, Tender Bender and Planes, Cranes, and Games (Douglas only)
- Season 10: Coal Crisis (cameo) and Groundhog Gordon
- Season 11: Around the Railyard in 64 Seconds (Douglas only, cameo), Big City Rumor, Station Situation (Donald only), Spencer Goes Too Far (Douglas only), Trembling Trevor (Donald mentioned, Douglas does not speak), Old Square Wheels (Donald or Douglas cameo) and Wooden Brakes (Douglas only, cameo)
- Season 12: Greetings, Montague! (Douglas only, cameo), Stafford's Electric Slide (Donald only), Scottish Blues, Gordon's Last Hurrah (Douglas only, cameo), Henry's Handcar Havoc (cameo), If The Dome Fits (Donald or Douglas cameo) and Vicarstown Takedown (Douglas cameo)
- Season 13: Bert's Arlesdale Fail and Toad Gets Towed (Douglas only, Donald mentioned)
- Season 14: Henry Gets Stumped (cameo), Double-Decker-Wrecker (cameo), Hiro and the Heat Wave (Donald only; cameo), Hugo Takes Flight (Donald only), and S.C.Ruffey's Sweet Tooth (Donald does not speak)
- Season 15: Flash Gordon (Donald only; cameo), Harvey's Happy Accident (Donald only), Tyrannical Rex (Douglas only; cameo),
- Thomas and the Storm (Douglas only)
- Lady the Lost Engine (Donald only)
- Claw of the Law
- Oliver's Eleven (Douglas only)
- Saving Pirate Ryan (Douglas cameo)
In Season 1, the two engines had different jobs on the railway,Donald pulls a special coach on his own branchline, however, his brother, Douglas is still a shunter in the yard and he doesn't like shunting that much, but after an accident, Douglas gets the job he had always dreamed of.
Donald and Douglas were bought from Scotland in 1959, Sir Topham Hatt introduced them to his railway then; the two were jokers but very excited. Sir Topham Hatt told them that painters will give the two numbers and nameplates. The two were indeed pleased.
After getting their numbers and nameplates, the two engines set off to work with Duck, they were proud of it and Duck told the two to watch out for Gordon, James and Henry, Donald and Douglas soon settled them and Donald accidently forgot to shunt Thomas' Special Coach. The Spiteful Brakevan was settled by Donald and the brakevan was soon in pieces!
They were pratical jokers but one of they're jokes got back at them when Donald and Douglas were taking a heavy load to Castle Loch; the mist lifted but Harvey and the Breakdown Train came to rescue them.
Donald and Douglas are pratical joker engines. They dislike to be parted and their jokes have continued and like Scotland but also like the Island of Sodor. The two are known by their original numbers.
BasisEditDonald and Douglas are based on a blue real tender engine. Several members of this class were built; only one is left as the sole survivor of the class.
- Donald and Douglas have made many cameos.
- They were seen in Keekre24's Wooden Railway Collection videos.
- "No, I'm Scottish, and I get to pull it."
- "But I'm Scottish, too."
- "I'm in this shed and the other side is sorrounded by animals, and you know I don't like animals."
-A talk between Donald and Douglas, A Scottish Tale, first season.
- "I know."
-Donald and Donald's Driver, Donald Visits The Scrapyard, third season.