Merlin is an Experimental Silver Tender Engine who believes He has The Power to Turn invisible.
Appearances:
- Season 14: Merlin the Magical Engine.
- Season 15: Nightmare on Sodor (fantasy;cameo)
- Season 16: Sweet Sixteen (does not speak)
- Season 17: Rocked by a Hurricane (mentioned)
Specials:
- Saving Pirate Ryan (cameo)
Trivia:
- Merlin is The first Custom Engine in Keekre24's Series (not counting Ben who received a custom yellow wooden model in CGI).
Gallery:
| Locomotives | SR | Stepney | Boxhill | Bluebell and Primrose | Adams | Merlin | Rebecca |
|---|---|---|
| LNER | Gordon's Brothers | Flying Scotsman | Pretty Polly | Lemberg | Green Arrow | Mallard | Silver Jubilee | Toby's Brothers | 1020 | 8783 | Spencer | 98462 and 87546 | |
| LMS | Jinty and Pug | The Foreign Engine | Bahamas | Duchess of Hamilton | |
| GWR | City of Truro | The Dukes | King James I | Iron Duke | Earnest | |
| BR | Diesel | Spamcan and Bowler | Old Stuck-Up | British Railways Diesels | D5705 | 31120 | 10751 | Barry | Diesel 10 | Splatter and Dodge | The Mainland Diesels | Paxton | Sidney | 'Arry and Bert | Den | Dart | |
| NG | Talyllyn | Dolgoch | Sir Haydn | Edward Thomas | Douglas | Prince | Russell | |
| Other | The Coalbrookdale Locomotive | Midland Railway Engines | Albert | The Highland Engines | Workshop Engines | The Foreign Engines | Scrapped Engines | Cromford | Captain Baxter | Stephenson's Rocket | Novelty | Sans Pareil | Wilbert | | Sixteen | Sixteen's Friends | Alfred and Judy | The Hunslet Diesels | Eurostar | Other Real Locomotives | Puffing Billy | The Mainland Engines | Billy | Hiro | Charlie | Neil | Connor | Caitlin | Samson | Logan | Sam | Lexi | Theo | Hurricane | Frankie | Norman | The Red Engines | River Irt | River Mite | Northern Rock | |
| Rolling Stock | Henrietta's Sister | Bluebell Railway Coaches | Thomas' Special Coach | Helena | Spencer's Coaches | Connor's Coaches | Caitlin's Coaches | Plank Trucks | Troublesome Trucks | Flatbeds, Conflats and Well Wagons | Ladle Trucks | Brake Vans | Bradford | |
| Vehicles | North Star | Mermaid Liverpool | Dilly | Beresford | |
| People | Elizabeth II | The Thin Clergyman | The Fat Clergyman | The Duke and Duchess of Boxford | |
| Locations | Vicarstown Bridge | Walney Channel | Barrow-in-Furness | King's Cross | Paddington | Euston | St. Pancras | Brighton | Carnforth | Crewe | Fletcher, Jennings & Co. | The Scottish Engine Company | The Great Railway Show Yard | The Mainland Canal | The Steelworks | The Experimental Engines' Yard | Bridlington Goods Yard | |
| Railways | Talyllyn Railway | Ffestiniog Railway | Snowdon Mountain Railway | Ravenglass and Eskdale Railway | Bluebell Railway | Dean Forest Railway | Toby's Old Tramway | |
