Diesel 10 (Pinchy by Andy Diesel) was a diesel engine equipped with a hydraulic claw, and had been brought to Sodor on multiple occasions. And was one of the diesel leaders during the Conflict.
Diesel 10 hails from the Packard and Sons Logging Railway in Ireland. His claw was invented and patented by Werner Obolensky, with the intention being for the diesel to be used for picking up trees. After a large storm hits Sodor, Diesel 10 is brought in by the Fat Controller to clear all the branches on the track. During his visit however, he became jealous of the attention a privately owned steam engine was receiving. One night, he sneaks up behind her, grabbing her with his claw and throwing her over the cliff of Quarry. Sir Topham Hatt quickly sends him away.
After Sir Topham Hatt's death, Alfred Herman took control of Sodor and brought him back to Sodor along with a whole bunch of other diesels form the inventor Rudolph Diesel, much to the horror of the steam engines. Later that night Diesel 10 is watching the unloading of a cargo ship at The Docks, but what is unloaded isn't ordinary cargo, but another diesel. At first 10 didn't recognized the strange engine, until he hears a familiar nickname he was once given nine years ago, "Pinchy". Once hearing it, he instantly recognizes the engine as his old friend Andy Diesel. After the two get reacquainted, Andy tells Diesel 10 that he had big plans for the North Western Railway and he couldn't do it alone.
At The Scrapyards, the warship attempts to convince the other diesels not to trust the steam engines, but they all remain doubtful, especially when Paxton questions weather what Diesel 10 said about the steam engines was true. But when Andy tells the other diesels the story of how he and 10 first came to Sodor, it worked and Diesel 10 and Andy became the founders and leaders of the steam hating group, known as the Oiler Committee. After Andy told the other diesels about Alfred Herman and the workmen leaving Sodor, they rallied the other diesels into taking over the Sodor Steamworks and kicking Victor out.
Sometime after the engines evacuated Tidmouth Sheds and left to seek refuge amongst the Skarloey Railway Engines, Andy told Diesel 10 that he found Lady's remains washed up on the beach, and decided to torchure the engines more by showing the remains to Duke at the Transfer Yards. Enraged Duke orders the two diesels to leave him and the other steam engines alone, and ordered the two to leave, which they do so. That night as Mr. M continued to break up Edward, Mavis and BoCo decided that they wanted out of the Oiler Committee but Andy and Diesel 10 don't take it ton lightly, and 10 uses Pinchy to rip Mavis' side plates off, while BoCo flees in fear. After this the two diesels return and capture Duke in the night and left his tender where Duncan found it the next morning.
Several nights later, Diesel 10 and D199 sneak to the Skarloey Railway and kidnap Percy and bring him up to The Quarry, then they place Splatter and tell him to pretend to betray the other diesels, which works and lures Thomas and Gordon into a trap, with Diesel 10 and Spamcan capturing Gordon and taking him to the Scrapyards leaving Thomas and Percy at the top of the quarry. The following night Phil Aardman, Oliver and Toad go out to find Thomas, Percy, and Gordon, when Phil was told what happened to Gordon, he buys the two tank engines some time by blowing up the entrance to the quarry so the diesels couldn't get them, but the noise caught the attention of the diesels, and 10 and Spamcan set chase after the three, but Oliver and Toad managed to escape. The next day Diesel 10 was clearing the entrance so he and the other diesels could capture and scrap the engines unaware that he was being spied on by Phil and Scruff, that night when he was done, Phil went into the quarry and rescued Thomas, but as the blue tank engine hadn't been moved in a long time, he ran out of water on the viaduct and was captured and taken to the scrapyards by Diesel 10.
During the events of "Authority", while Andy and Dodge went out to destroy the remaining steam engines, only to be blown up by Diesel, Diesel 10 and the others were about to scrap Thomas with the help of Mr. M after Thomas had failed to reason with him, but were thwarted once and for all when BoCo with Annie and Clarabel, and the U.S Army General Robert Stewart, and the diesels were going to be left at the scrapyards until they could be sent back to the mainland, but with the rails near McColl Farm destroyed, Phil ordered the diesels to clean up the mess they had made on Sodor, with Diesel 10 shunting in the yards, asking who the new express engine would be, Phil having enough with 10 sent him back to Ireland in disgrace, and much to his missary, reuniting him with Bash, Dash, and Ferdinand.
During the events of "Inheritance" Diesel 10 could be seen scuttling around the Packard and Sons Logging Co. with Thomas who had been sent there by Stephen Hatt during his control over Sodor.
Diesel 10 remained in Ireland until 1958, where he along with 7101, were sold to the United States. In 1965, Phil purchased the two not knowing Diesel 10 was one of the diesels. Phil was Skeptical of Diesel 10, however Diesel 10 claimed to be redeemed, and was put at work repairing the quarry.
Diesel 10 eventually turned out to have not reformed; after spotting Ryan high up on the quarry cliff side, he mistook him for Thomas and declared that he would finally exact his revenge on him after more than 20 years of plotting against him.
In "Sins", he bumped Ryan towards the edge of the cliff, Ryan was pushed off the rails because Thomas bumped Diesel 10. Thomas told Diesel 10 that he does not care about wining as long as Diesel 10 lost once & for all. Thomas then pushed Diesel 10 off the cliff & he was pulled down with him.
- Season 1: Modernization Marches On (flashback, does not speak)
- Season 4: Ballast (flashback, does not speak), Runaway & Sins (death)