Stanley's popularity caused Thomas to feel jealous and later neglected. Thomas felt that Stanley was newer, bigger, and stronger than he - and would take over 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 realise 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 smokebox certainly makes him look the part as he eagerly goes about his work.
- Stanley is best friends with Caramel.
- 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 smoke box is silver, however in real life, UK locomotives have black smoke boxes.
- Stanley will guest star in Thomas and Twilight search for Arthur's Missing Pal, Thomas, Twilight, James and the Giant Peach, Thomas and Twilight Sparkle's Adventures of Chicken Little, and Brian Griffin visits Jurassic World.