Diesel 10

Diesel 10, or simply Diesel, was an evil diesel engine who antagonized the steam engines of Sodor, but has now since became an ally and friend to the steam engines. He has a semi-sentient roof-top, hydraulic claw, which he has named "Pinchy".

Biography on YouTube
Diesel 10 first appeared on Sammy Clark's YouTube channel in the video, "Thomas and friends Welcome to my Trainmare part 1", and his first appearance in the SC Shorts was in the episode, "Joy To The Rails Part 1".

Personality
Originally, Diesel 10 was a evil, conniving, manipulative, bullying and raving diesel locomotive. He absolutely despised steam engines, would call them taunting names like "Puffball" and "Teapot" and is not above doing anything to get rid of them if possible. He is Sodor's strongest (but not quite largest) diesel, his power being enforced by his slightly malfunctioning claw, Pinchy. He can use this deftly, and is even able to use it to make a sculpture. Pinchy, though, seems to have a mind of its own, as it has been shown to "punch" Diesel 10 in the face from time to time, which he loathes. All engines, steam and diesel alike, fear or respect him.

After failing at many attempts to beat the steam engines of Sodor, Diesel had enough and banished Diesel 10 from the Dieselworks, couraging him to get back at Diesel one day. Sometime later after finding out that Diesel was purposely causing the steam engines to have accidents and overworking the diesels, Diesel 10 (along with Philip) decided to prevent the accidents from happening to stop Diesel's devious plan. And once Diesel 10 saved Thomas along with the broken engines at the Steamworks, Diesel 10 gained the trust of all of the steam engines on Sodor and became a friend to all of them.

Trivia

 * In "Joy To The Rails Part 1", it was revealed that Diesel 10 was fired after the events of "The Missing Christmas Decorations" from the official Thomas & Friends series, and was stuck at Mattel Head Quarters making toys for the show for the next few years. Hence why Diesel 10 is still made into merchandise despite his discontinuation to the show.
 * Diesel 10's catchphrase in the SC Shorts is, "Oh bollox".
 * Diesel 10's song (I Am Diesel 10) from "Green Eggs And Boxcabs" is based on the song, "E.G.G.M.A.N." from "Sonic Adventure 2".
 * Diesel 10 and Diesel were good friends up until the ending of "Best Friends Forever Part 3" when Diesel kept on telling Diesel 10 on how both him and his plans suck.