Diesel 10

First off
http://ttte.wikia.com/wiki/Diesel_10 This is a link to the  real  Diesel 10 this is simply an interpratation

Befor Sodor
Diesel 10 was always mistreated by steam engines for being different, often being bullied to the point where he wouldn't want to come out of his shed. His Controller sent him to the scrap yard and had Pinchy installed onto him as so he could move the heavy scrap around. One day a steam engine came in and started making fun of him, in rage he took a chunk out of the engine's boiler. His Controller locked him up In his shed for a long time. One day his Controller came to his shed and told him that he was going to a new railway.

On Sodor
Diesel 10 quickly hated the idea of a near all steam railway after what he had been threw. Quickly making himself seem tough and scary he bullied the steam engines so he would not be. After TATMR he was locked up for several years, then let out to start work again. He kept to himself but would occasionally bully others to seem tough.

Persona
Diesel 10 keeps to himself mostly but will cause a stir once and awhile, once you become his friend or he trusts you he can be rather shy and open, oddly enough Edward and Sidney are the only ones that see this side of him. Diesel 10's real name is Bobby, but only Edward is the only one that ever asked, and sometimes calls him by his real name.

Romance
In quote from Fire-Cooking her self. "No, Absolutely not, well not yet anyways."