Stanley is a friendly white tank engine who came to do Thomas' work during the Great Waterton restoration.
When Thomas discovered the long-forgotten town of Great Waterton, The Fat Controller kindly put Thomas in charge of its restoration. Knowing that another engine would be needed to run the branch line as well as keep trains running to this isolated town, he knew that a new engine would be necessary to keep things running smoothly. Stanley arrived at Brendam Docks to join the team, and was well-liked by all the engines. Things could only get worse when Thomas had an accident, and Stanley was put in charge of all the work being done at Great Waterton. Stanley, being clever and gregarious, made it as smooth of transition as possible. Thomas, however, was jealous. So jealous in fact, he purposely shunted a line of trucks he knew Stanley could not handle on the hill by himself. The trucks broke away, and crashed into the Great Waterton Tower. Ashamed, Thomas tried to make amends but got lost in the process, and was rescued by none other than Stanley himself, who could not hold a grudge. The two engines are now firm friends.
Stanely also rescued Thomas when his brakes failed on a river bridge under construction.
Stanley works near Great Waterton and Sodor Logging Co., but the Fat Controller never hesitates to assign him with odd jobs. On one occasion, Stanley was sent to help 'Arry, Bert, and Spitzer at the smelters. The diesels had a very grim perception of the state of the world and the future of steam, and this made Stanley very upset. Demoralized, things did not improve when Diesel arrived with even more foreboding and conspiracy theories to bring him down. Thankfully, Edward arrived and cleared things up, with Stanley well aware that optimism, the future, foreboding are up to interpretation.
Stanley was also sent to collect ballast from The Little Western Extension. On his journey, he met Mike and Frank the Arlesdale engines. When Stanley tried to whistle hello, his whistle made an awkward sound he had never heard before. To make light of the humorous happenstance, Mike told him the story of how his whistle came loose and shot off like a rocket. Amused, Stanley left the Little Western Branch Line unaware that this story would save his driver and fireman's life later that day! When Stanley was patrolling an abandoned waterworks near Great Waterton, he fell through the floor and smashed an aquaduct! A rapid flow of water filled the room, and with his last ounce of steam, Stanley shot off his loosened whistle like a rocket to knock a grappling hook of off a platform so his driver and fireman could escape the watery grave. He was rescued the next day from the flood of water, and the Fat Controller promised him a new coat of paint.
Stanley was at Killdane when Culdee and Derek passed bound for Kirk Machan. He expressed curiosity for what happened to Culdee, but was advised by Hank not to further press the issue out of respect for Culdee.
Stanley is outgoing, gregarious, and friendly. He can make friends easily and an exceptional leader. He is confident, but not too cocky, and is a genuine friend to all. Even Stanley can get disillusioned sometimes, but since he is in such good company on Sodor, he gets back on his wheels in no time at all! Stanley is close friends with Hank and Scruff.
- Season 1: Lift Bridge (cameo), Swagger and Swerves (cameo), Snow Blind (cameo), Buffer Bashing (cameo), Will Power (cameo), Scruff's Scaffolding (cameo), Will Power (cameo), Conspiracy Theory
- Season 2: Paxton and Norman (cameo), Breakdown Blues (cameo), Mavis and the Tornado (cameo), Rosie (cameo), Young Tucker (cameo), Waterworks, Rock-Star, Tag-Team (cameo), Munitions (cameo), Swan Dive (cameo), Aura of Menace, Henry and Kurt, Swashbuckler (cameo)
- Season 3: This Too Shall Pass (cameo), Samson, BoCo, and the Man in the Hills (cameo), Culdee Fell, Derek and the Two Faced Engines (cameo), The Suggestion Box (cameo), Penn Pals (cameo), Ice Breaker (cameo), Chivalry is Dead (cameo)
- Web Clips: Mike and Frank Banter: SLOTLT, ScarletFire, and EE93's Return (cameo)
He may appear in Self-Fulfilling Prophecy.