Class 40

Class 40, also known as The Diesel, D4711 (in the Railway Series), D261 (Thomas & Friends), or simply Diesel is a diesel engine who once visited the North Western Railway on loan from British Railways. Many years later, he came back to Sodor by accident and was later allowed to stay on the railway after saving James from a nasty accident.

Biography in the SC Shorts
Class 40 was built at the Vulcan Foundry in Newton-le-Meadows, Lancashire, England. Class 40 was sent to Sodor in 1962 to assist the engines with goods and express work toward the end of Stepney's visit, but he only insulted the other engines by saying they were out-of-date, should be scrapped and bragged about his modernity. He got his comeuppance when an inspector's bowler hat jammed in his air intake, causing him to break down and to become as sick as boiler sludge. He sulked in the shed while Duck and Stepney took the Express for him to Crovan's Gate.

While everyone was fare-welling Stepney, a disgraced Class 40 crept away, leaving behind "a rather nasty smell of bad manners and a battered bowler hat".

Sometime later after not getting transferred to the No Longer Used Character Scrapyard on Sodor, Class 40 was transferred to the Mainland and worked there for a few more years until he started getting used less and less due to the arrival of more newer and efficient locomotives.

In 2021, Sir Topham Hatt loaned Dimitri from the Mainland to help out with the extra freight and passengers on the island. However according to Dimitri, when looking for him, the Mainland Controller had accidentally sent Class 40 off to Sodor instead of Dimitri. And when realizing his mistake, the Mainland Controller just told Dimitri to tell Sir Topham Hatt that he could have Class 40 for free because he isn't used that often on the Mainland anymore. With that said, Sir Topham Hatt decided to give both Dimitri and Class 40 trials to see whether or not their worthy on staying on Sodor or not.

The next day, Class 40's vacuum brake ejector failed while pulling passenger coaches. Ferdinand, who was already towing Dimitri and his freight train, came to help; Class 40 was still able to move by himself with some help from Ferdinand. To the passengers' delight, Gordon took their train, while Ferdinand helped Class 40 to the Dieselworks. Along the way, Ferdinand told the diesel about his failed regulator. Class 40's opinion of steam engines was greatly changed after the incident.

Though Sir Topham Hatt gave him a second chance, Class 40 was still not accepted by James who remained suspicious of him. He soon changed his views on Class 40 when he had an accident with some freight cars and Class 40 helped him out. Following this act of heroism, Class 40 was officially accepted onto Sir Topham Hatt’s Railway.

Personality
When Class 40 first came to Sodor, he was snobbish and rude, believing that diesel engines were superior and should take over from steam engines. But over the time of him living on the Mainland, he started to appreciate steam engines more and became more polite and kind-hearted towards them, and often helps them out when they're in a predicament.

Trivia

 * The voice that Sammy Clark provides for Class 40 is based off of GeebMachine's voice for him in the Thomas Creator Collective.
 * Him being more kind-hearted to steam engines is also based off of his current personality in the Thomas Creator Collective.
 * Class 40 reuses Wilson's horn sound from Chuggington.
 * Thomas himself even mentioned in "Super Rescue" on how he originally thought that Class 40 was Wilson due to his horn sounding identical to his.