Hiro is a wise Japanese engine.
Hiro is wise, very dignified, and enormously kind. He is friendly and is able to find good in any engine he meets. He does not appear to hold a grudge; in his first appearance, he helped Spencer after an accident, despite Spencer previously trying to send Hiro to the smelter's yard.
Hiro once lived on a faraway island. He was the strongest engine on his railway, and was famously known as the "Master of the Railway". He was eventually brought to Sodor where he worked for many years. However, he began to show his age, and the works did not have the necessary parts to repair him. To escape being scrapped, he was put on a siding, where he had to wait for the parts to come from his homeland. However, the parts never came and Hiro was all but forgotten.
Thomas eventually found him and, fearing Hiro would be scrapped if he was not Really Useful, promised to bring him back to his former glory while keeping him a secret from Sir Topham Hatt. Thomas also had many of his friends help in the restoration, and Hiro quickly gained their friendship. After breaking down again while trying to avoid Spencer, Hiro was hidden away in another siding, where passing engines visited him and kept him company.
When Sir Topham Hatt found out about the situation, Hiro was brought to the Sodor Steamworks, where Victor oversaw his restoration. Once Hiro was restored, he helped Spencer after his accident, and worked with him and Thomas to finish the Duke and Duchess's summer house. Despite everything, Hiro had grown homesick, so Sir Topham Hatt arranged for him to be sent back to his homeland.
Hiro eventually came back to Sodor to help the engines with the summer holiday traffic. Upon his arrival, Hiro went to the Steamworks to be examined and then went to Knapford station for his welcome party, which was almost delayed as Thomas was trying to find a welcome present for Hiro instead of telling the other engines about the party. But, Hiro told Thomas that having his friends at the party was the best welcome present. During his visit, Hiro told Thomas to take the load of bees through the woods, which Thomas ignored. However, Thomas took Hiro's advice after taking Hiro's flower truck to get the bees back to their hives. Later on, Hiro saw the Fat Controller, and assumed he was too busy to give orders to his engines. So, he tried to help the Fat Controller by giving out the orders - but he only succeeded in becoming "Master of the Muddle". However, he made up for his mistakes by telling the engines to go to Knapford and await orders from the Fat Controller.
Hiro is still on loan to the Fat Controller. He saw Jobi Wood being delivered to the Docks and told Thomas about where it came from. He later pushed Henry to the Steamworks to have his side-rods repaired. And when Hiro became homesick, Thomas took him to Misty Island, which reminded Hiro of his home.
Later, Hiro, along with Henry, takes on some bad coal. While Henry does not want to carry on, Hiro is determined to get the job done. He does so, but during his next job of transporting girders with Henry, Hiro breaks down and Henry has to come to the rescue.
Hiro is an old steam engine who has been on Sodor for a very long time and was originally known as the "Master of the Railway". He is grand, masterful, and mature. He has an appreciation for serenity and order and often thinks fondly of his homeland, far away, where he was once one of the strongest engines. Hiro fell victim to neglect when waiting upon parts to arrive for him from his island, when he began to break down and became lost. He was eventually rediscovered by Thomas, who, despite some problems in worrying about sharing the discovery of Hiro with the Fat Controller, helped Hiro be fully restored to his former glory. Hiro continues to be gentle, wise, and graceful, as well as a useful engine on the railway and good friend to the other engines, especially Thomas.
Hiro is a Japanese National Railways (JNR) Class D51 built by Kawasaki. However, Hiro runs on standard gauge track, while the real D51 engines were built for cape gauge.
Hiro is painted black with gold bands and fittings and red wheels. His name is written in black on gold nameplates on his smoke deflectors. He has the number "51" painted on the sides of his tender in white. His "patchwork" colour scheme consists of some blue, green, purple, and rust coloured parts.
- Season 13 - The Biggest Present of All, Buzzy Bees, and Hiro Helps Out
- Season 14 - Thomas' Tall Friend (cameo), James in the Dark (cameo), Toby and the Whistling Woods (cameo), and Henry's Health and Safety
- Season 15 - Emily and Dash, Happy Hiro, Kevin the Steamie (cameo), Wonky Whistle (cameo), and Fiery Flynn
- Season 16 - Race to the Rescue (cameo), Express Coming Through (cameo), Ho Ho Snowman (cameo), Flash Bang Wallop! (cameo),Thomas and the Rubbish Train (cameo), Thomas Toots the Crows (cameo), and Sodor Surprise Day (cameo)
- Season 17 - Henry's Hero
- 2010 - The Best Present of All, Buzzy Bees, Hiro Helps Out, and Misty Island Rescue (cameo)
- 2011 - Hiro Helps Out
- 2012 - Making Hiro Happy
- Togo Igawa (US/UK)
- Tesshō Genda (Japan; Hero of the Rails onwards)
- Helge Winther Larsen (Norway; Hero of the Rails onwards)
- Janusz Wituch (Poland)
- Hiro says that he is the oldest engine on the Island, but the D51 class was not built until 1936, making him much younger than most of the other steam engines on the island.
- Before the Thomas and Friends website's overhaul, Hiro's profile specifically mentioned that he is Japanese.
- According to Christopher Skala, Hiro was originally going to be painted blue.
- Like Hank and Flora, Hiro has only been partially modified to work on Sodor. He has been scaled up to standard gauge, and has been given buffers on his front and his tender. But oddly enough, he has a loose coupling on his tender, and a knuckle coupling on his front. This would make pushing rolling stock or being pulled away by another engine physically impossible, unless a special adapter used to connect knuckle couplers and loose couplings was fitted onto his knuckle coupling.
- In the Norwegian narration, Hiro is known as "The King of the Railway".
- Though Hiro's number is a reference to his class, there really is a D51 with the number 51. However, unlike Hiro, the real engine is an earlier build of the D51 class, with its dome flush with its funnel. It is preserved at Torokko Saga Station in Kyoto, Japan.
- Wooden Railway (normal, "patchwork", "lost and found", and battery powered)
- Take-Along (normal and "lost and found"; discontinued)
- Take-n-Play (normal and "patchwork")
- Motor Road and Rail (normal and patchwork; Asia only)
- TrackMaster (normal, talking "lost and found", and R/C)
- My Thomas Story Library (discontinued)
- Wind-up (normal, metallic, and "patchwork"; Japan only)