Diesel 10, which he was named due to him being the tenth diesel to arrive on Sodor is a ruthless diesel engine with a roof-top, hydraulic claw, which he has named "Pinchy" he is a recurring antagonist in Thomas the Tank Engine & Friends as well as the main antagonist in Thomas and the Magic Railroad and Day of the Diesels, he is an evil, conniving, bullying and raving diesel locomotive, in all of his appearances, excluding Thomas and the Magic Railroad and Misty Island Rescue, Diesel 10 shows a caring side at the end of every special/episode and as a hero, he helped clean the wreckage of the Sodor Airport in Calling All Engines! when Thomas shunted some flatbeds into a water tower and in Day of the Diesels, he helps rebuild the dieselworks along with the other engines and once when he stole the Christmas decorations from Tidmouth Sheds, after realising that the steam engines get all the decorations while he and the other diesels don't, they decide to give the decorations to the steamies, so that they and the diesels can enjoy Christmas together, he also tries to prove to the Fat Controller that he can be a really useful engine.
Diesel 10 once visited the Island of Sodor a long time ago, and caused trouble for the steam engines while he was there. During his visit, he found Lady, the engine responsible for keeping Sodor alive, and chased her, making her crash. Following the accident, Lady's caretaker, Burnett Stone, hid Lady in his workshop and tried to restore her, but failed to bring her back up to steam.
Several years later, Diesel 10 returned to Sodor when the Fat Controller was on holiday, intending to destroy Lady once and for all. He was first seen by Thomas and Gordon when he raced past them at Killaban Station, and brought his two lapdogs, Splatter and Dodge, to the railway, who were present when he was scheming. He caused several problems for the steam engines, such as dumping sneezing powder around Tidmouth Sheds and later destroying the scaffolding that had been placed beside the shed.
When Mr. Conductor travelled across Sodor to find the windmill, Diesel 10 found him and held him over a viaduct, intending to drop him. However, Mr. Conductor managed to escape by cutting the hydraulics to his claw with a pair of wire cutters, causing him to fling Mr. Conductor across the island and to the windmill. Diesel 10 was later present at the coaling plant, where he was covered in coal when he was teaching Splatter and Dodge “how to stop being stupid”. After Junior flew in the air after riding the windmill's sails, he landed on Diesel 10's cab, who raced across the island and to the smelter's yard, where he tried to push James and Junior into the melting pit. Fortunately, Junior and James managed to escape by using the last of the former's gold dust.
After Lady was brought back up into steam and returned to Sodor, Diesel 10 found her and began to chase her, Thomas, and Burnett across the island, until they reached the viaduct. Lady, Burnett and Thomas managed to cross the viaduct safely, but Diesel 10 was too heavy for the rails and plunged into a barge of sludge below the bridge, and was sent away in disgrace.
Diesel 10 later returned to Sodor years later under unknown circumstances. It can be assumed, however, that Sir Topham Hatt decided to give him a second chance. He was seen working at the scrapyard, loading piles of scrap into trucks. The very sight of his return caused Thomas and Percy to shudder in fright.
When the steam and diesel engines were holding a meeting at the coaling plant so that they could work on the Sodor Airport, Thomas was sent to the scrapyards to inform Diesel 10 of the meeting. However, Thomas was too scared to meet Diesel 10 again, and sped away as fast as he could, not believing that Diesel 10 would want to help the steam engines due to their difficulties in the past.
Soon, the airport was nearly complete with its construction, until a water tower collapsed, cracking the runway and blocking the line. With Harvey all the way on the other side of the island, Thomas went to ask Diesel 10 for assistance. After some slight hesitation, Diesel 10 agreed to help clear the wreckage.
After Thomas was found prior to the reopening of Great Waterton, Diesel 10 was among the diesels present at the quarry when they heard the news. Later, when the Sodor Search and Rescue Centre was opened, Diesel 10 was present at the rescue centre's grand opening, standing on a cliffside overlooking the rescue centre and the steam engines below, threatening to return.
When Percy was experiencing a falling-out with Thomas, Diesel 10 decided to manipulate him into helping him restore the Sodor Dieselworks, by having him visit the Dieselworks and befriend him. Diesel 10 managed to convince Thomas to arrive at the Dieselworks, where he was held hostage while he, Percy and the other diesels went to the Sodor Steamworks. Once there, Diesel 10 betrayed Percy and took over the Steamworks. Percy returned to the Dieselworks to rescue Thomas, when he noticed that sparks from Pinchy had set the main building ablaze. After Thomas was saved and the fire was put out, Percy, Kevin and the rest of the Steam Team went to the Steamworks. After a brief argument with the diesels, Sir Topham Hatt arrived and, after being told about the state of the Dieselworks, agreed to have the place restored. Diesel 10 and the other diesels worked alongside the steam engines to restore the Dieselworks, and he became the new head of the Dieselworks, with Den and Dart taking over in his absence.
When it was Christmas time, Diesel 10 became jealous of the steam engines for having more decorations at Tidmouth Sheds than he and the diesels had at the Dieselworks. He began stealing decorations from the sheds to bring to the Dieselworks, enlisting a reluctant Paxton to help him. Diesel 10 was caught by Percy, who chased him back to the Dieselworks with the rest of the Steam Team, where Diesel 10 found out that Sir Topham Hatt had, in fact, had Paxton deliver some decorations to the Dieselworks. The next day, Diesel 10 gave the decorations back to the Steam Team, but as most of them had been damaged, he gave them the Dieselworks' decorations too, as he and the other diesels considered Sidney to be a good enough decoration.
Diesel 10 is an evil, conniving, bullying, and raving diesel locomotive. He absolutely despises steam engines, and would call them taunting names like "puffball" and "teapot". 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 hates very much. All engines, steam and diesel alike, fear and respect him.
Despite his aggressiveness, he will help on occasion since Sir Topham Hatt brought him back, but only when it suits his personal interest. He has a caring side, but he very rarely shows it.
Diesel 10 is a BR Class 42 "Warship" with an added non-regulation hydraulic claw. Two of these engines are preserved.
Diesel 10 is painted ochre with tan stripes. His bufferbeams are painted red and his buffers and Pinchy are painted dark brown.
Behind the Scenes
In Thomas and the Magic Railroad, Diesel 10 was originally played by Australian actor Keith Scott, and the character was intended only as a villain supplementary to Doug Lennox's character, P.T. Boomer. Boomer was cut due to early audience reactions, and Diesel 10's role was rewritten as the primary villain. In the process, Keith Scott was replaced by Canadian improv comedian Neil Crone. Crone, with fellow improvisation comedian Kevin Frank, had been auditioning for the film to play the trucks. Crone was given the part of Diesel 10 when he was heard performing a gruff voice during auditions. In the final movie, Crone and Frank improvised much of their dialogue, including the name "Pinchy" for Diesel 10's claw.
His plan in the original script was also much different. He plotted to get rid of the steam engines by making their lives miserable, one of the sections of the plan included the "Sneezing Powder" sequence (originally quarry dust in the original script and Little Engines Can Do BIG Things). He also planned to destroy all the buffers on the railway so the steam engines would crash and derail, with the diesels taking over and rebuilding the buffers after. The plan to destroy the buffers was further bolstered by his discovery of the buffers that led to the entrance of Mr. Conductor's Magic Railroad, thus stopping him from continuing his plans of diesel domination. This plan was the reason why George was going to be one of his assistants. Also, instead of returning to Sodor to finally destroy Lady once and for all, he was a new engine who Sir Topham Hatt brought to help while he was away, but instead caused more havoc on the island.
- According to The Real Lives of Thomas the Tank Engine, Diesel 10's hydraulic claw, Pinchy, is an illegal modification. Among other reasons, it makes him too tall for the British loading gauge.
- In an original version of the Thomas and the Magic Railroad script, Diesel 10 was to have been a new engine to the island, and Pinchy was going to be concealed beneath Diesel 10's roof. These were kept in the book, Diesel 10 Means Trouble, the magazine story Left Alone also possibly has him illustrated without his claw.
- "Pinchy" was originally built with no gaps between its buckets, which carried onto early promotional arts/illustrations.
- Diesel 10 is the only character from Thomas and the Magic Railroad to appear in the CGI Series.
- Diesel 10 only appeared in specials and movies until the seventeenth season, where he appeared in an episode for the first time.
- Diesel 10 has never been seen pulling any sort of rolling stock.
- In Thomas and the Magic Railroad, Diesel 10 is only addressed as "Diesel" aside from his introductory scene and the scene where Mr. Conductor explains to Billy Twofeathers why he is going to Sodor.
- It was widely speculated that Diesel 10's name may have derived from the fact that he was the tenth diesel introduced in the television series, but Britt Allcroft says the name just "popped into her mind".
- According to Mr. Conductor, putting sugar in his fuel tanks would make him stuck.
- Diesel 10 has had a few modifications throughout the television series. These include:
- Calling All Engines!
- His brake pipe was removed.
- The wipers on his front windows were removed.
- Misty Island Rescue
- The 'teeth' on his claw now interlock.
- Calling All Engines!
- In early concept art, Diesel 10 had his name painted on his side. In addition, his claw bucket was smaller, his arm was designed differently, and he had three brakepipes, whereas his final model only had one.
- He has never been seen with an operator or driver.
- Diesel 10 has the same horn sound as Phillip and Filmore from Theodore Tugboat.
- His ERTL model depicts him as a BR Class 46 with added claw, this is due to re-using D199's tooling but modifying accordingly.