Stanley is a silver tank engine.
Stanley's popularity caused Thomas to feel jealous and later neglected. Thomas felt that Stanley was newer, bigger, and stronger than he - and would takeover his place on the railway. Thomas then planned to make Stanley look weak - the trick backfired and caused Thomas' friends to consider him mean and incompetent.
When Thomas later went missing, Stanley was the first to realize Thomas' feelings. He searched for Thomas until he finally managed to find and rescue him. Then, both became friends and with a combined effort made it back to Great Waterton in time to prepare for the opening celebrations.
Stanley was amongst the engines at Knapford who were worried about Percy's whereabouts when Percy was spending his time with the Diesels at the Dieselworks. Later on in the winter, he suffered from a faulty firebox and Thomas came to his aid once again.
In more recent seasons, Stanley can be seen working at the Shunting Yards, the China Clay Works and Ffarquhar Quarry. Salty also mentioned that Stanley, in one of his spooky stories, was an old engine who lost his flatbeds while climbing a hill, and ever since then his flatbeds haunt the rails.
Stanley is the "boy-next-door" of the Fat Controller's Railway. Cocky, cool, and cheery, he is a little bit bigger, a little bit newer, and a little bit stronger than Thomas, which, at first, made Thomas jealous when all focus seemed to be on this shiny, new arrival, especially when he began helping with the restoration of Great Waterton. However, even Thomas was soon won over by Stanley's positive attitude, charm, and friendliness and came to see why he was so popular and well-liked among the other engines. As such, Thomas and Stanley are now firm friends. There is nothing Stanley would not do for another engine. And if he could not do it, he would find someone who could. He is sleek, smart, and stylish and his silver and light grey appearance, with striking red wheels and a shining smoke box certainly makes him look the part as he eagerly goes about his work.
Stanley is a hybrid cross of a Hudswell Clarke 0-6-0ST engine and Kitson's No. 5459 "Austin I", but with a taller funnel.
Stanley is painted in a white livery with a metallic silver smoke box, red wheels and lining. He has a red running plate with a dark grey basecoat, and his name on each side of his saddle tank.
He plays Tarayzan in Thomas (Rayman) (Julian Bernardino's Style)
- He is Rayman's friend.
- Season 12 - James Works it Out, Gordon Takes a Shortcut, and Thomas Puts the Brakes On
- Season 14 - Thomas' Tall Friend (cameo), Merry Winter Wish (cameo), and Thomas and the Snowman Party (cameo)
- Season 15 - Percy's New Friends (cameo), Surprise, Surprise, and Kevin the Steamie (cameo)
- Season 16 - Old Wheezy Wobbles (cameo), Percy and the Monster of Brendam (cameo), Flash Bang Wallop! (cameo), Thomas and the Rubbish Train (does not speak), Salty's Surprise (cameo), Emily's Winter Party Special (cameo), and Muddy Matters (cameo)
- Season 18 - Flatbeds of Fear (not named (does not speak)), Disappearing Diesels (cameo), Signals Crossed (cameo), Toad's Adventure (cameo), Thomas the Quarry Engine (cameo), Marion and the Pipe (stock footage cameo), Missing Gator (cameo), Timothy and the Rainbow Truck (cameo) and Samson at Your Service
- Season 19 - The Truth About Toby, Very Important Sheep (cameo), Helping Hiro (cameo), Philip to the Rescue (cameo) and Thomas the Babysitter (cameo)
- The Great Discovery
- Misty Island Rescue (cameo)
- Day of the Diesels
- Blue Mountain Mystery (cameo)
- Tale of the Brave (cameo)
- Sodor's Legend of the Lost Treasure (cameo)
- The Great Race
- 2013 - Gordon's Shortcut
- Matt Wilkinson (UK (fifteenth season onwards - excluding nineteenth season))
- Ben Small (US (fifteenth season - eighteenth season))
- David Menkin (US (Samson at Your Service only))
- Rob Rackstraw (UK (nineteenth season only) - US (nineteenth season onwards))
- Hiroshi Tsuchida (Japan)
- Benjamin Morik (Germany (fifteenth season onwards))
- Christoffer Staib (Norway (fifteenth season only))
- Stig Krogstad (Norway (Day of the Diesels onwards))
- Adrian Perdjon (Poland (fifteenth season and Day of the Diesels))
- Piotr Warszawski (Poland (eighteenth season onwards))
- José Luis Rivera (Latin America (Day of the Diesels onwards))
- Mercedes Espinosa (Spain (Day of the Diesels onwards))
- Anton Savenkov (Russia (Samson at Your Service onwards))
- One of Stanley's models used to be on display in Canada at Nitrogen Studios.
- Stanley's popularity with the public has grown following an online video called "A Toy Train in Space", in which a Wooden Railway model of him was sent into space. As a result, both a Take-n-Play and a Collectible Railway "Stanley in Space" have been released.
- Stanley's smokebox is silver. However in real life, UK locomotives had their smokebox painted in black.
- Stanley's whistle sound is Thomas' at a lower pitch.
- Stanley's Track Master model features wheel arches.
- Stanley has had several modifications throughout the television series. These include:
- Season 14:
- His smokebox became shorter in height.
- Season 19:
- He gains a brake pipe.
- He received permanent head and tail lamps.
- He gains a lamp-iron.
- He received front and rear brake-pipe outlets.
- Season 14: