Henry is a large LMS Stanier 5MT mixed traffic engine. Originally the hybrid shape of an GNR A1 Pacific and a GNR C1 Atlantic and a poor steamer; Henry was rebuilt into his current shape in 1935. Henry is a kind engine, but can sometimes be grumpy and of a worrying persona.
Henry is generally well-behaved, but he is occasionally arrogant and vain. Henry is at heart a hard worker, but his frequent bouts of illness hinder his work. His illness almost always involves his boiler having some sort of issue.
In the television series, Henry has been portrayed with a much kinder and softer personality. He has been shown as a nature-lover as evidenced in Henry's Forest. This personality carried on throughout the more recent seasons with Henry being occasionally a tree-hugging engine too as he tried to prevent the tall pine tree and the wishing tree from being cut down.
In the newer seasons, particularly Season 19, Henry is portrayed as not too bright and sometimes really worrisome, as shown in multiple episodes. This worrisome personality was also featured in The Adventure Begins which greatly contrasts to the original version of The Sad Story of Henry.
However, in Season 17 and Season 20 onwards, he has shown instances where he was either grumpy, arrogant or vain, proud and strong and he even once tricked Gordon into doing work again.
Henry's history is unusual. He was built from rejected plans for Sir Nigel Gresley's A1. The plans were stolen from Gresley by a rival. The resulting engine was a mix of a GNR A1 Pacific and a GNR C1 Atlantic, with a 4-6-2 wheel arrangement. Henry in this shape developed performance issues from flaws in the design, compounded by his stay in the tunnel. Henry was a bad steamer: with good-quality coal he could get enough heat to make plenty of steam, but when there was a poor lot delivered, his undersized firebox could not hold enough coal to make a proper fire. On advice from Henry's fireman, the Fat Controller ordered high-grade Welsh Coal, which made an appreciable difference in Henry's performance. When Henry suffered an accident and severe damage that winter, the opportunity was taken to send him to Crewe, where he was rebuilt an LMS Stanier 5MT "Black Five" 4-6-0. After "The Eight Famous Engines," Henry's LMS Stanier 5MT tender was replaced by a Fowler tender.
In the television series, Henry has always had a one-window cab with an LNER-style tender. The main difference between his shapes was removed splashers and the Belpaire firebox replacing the tapered. This was done to ease the changeover to his "Black Five"-esque appearance.
Henry is currently painted NWR green with NWR red-and-yellow lining and the number "3" painted on his tender sides in yellow. He was originally painted LNER green, but he was repainted NWR blue with NWR red and yellow lining at the end of "The Three Railway Engines" and remained so until the beginning of "Troublesome Engines," when he was given back his own livery. In "Henry and the Express" he was briefly painted orange-red as an undercoat before his standard green coat was applied.
In the Railway Series, he carries two builder's plates on the sides of his cab.
- Season 100 - Geoffrey's Real (does not speak), Toby and Philip (cameo), Henry the Warrior, Diesel Saves the Day (cameo), Trouble with Brakevans, Jealous James, The Crashing Kipper, Mike and James (cameo), The Lost Letters (cameo), Snowploughing at Christmas, The Christmas Engines (cameo), Duncan's Dilemma (cameo), Henry in the Darkness, and Timothy and the Aquarium (cameo)
- Kevin Frank (Thomas and the Magic Railroad)
- Keith Wickham (UK; Hero of the Rails onwards)
- Kerry Shale (US; Hero of the Rails onwards)
- Ryō Horikawa (Japan; first - eighth seasons)
- Kenji Utsumi (Japan; James and the Trouble with Trees (First half))
- Junichi Kanemaru (Japan; Calling All Engines! onwards)
- Kenta Miyake (Japan; Edward the Hero)
- Nozomu Sasaki (Japan; Day of the Diesels)
- Fabrice Trojani (France and French speaking Canada)
- Espen Sandvik (Norway; Hero of the Rails - Tale of the Brave)
- Ambrogio Colombo (Italy)
- Blas García (Latin America; Thomas and the Magic Railroad)
- Carlos Segundo (Latin America; Thomas and the Magic Railroad; TV Version)
- Ricardo Silva (Latin America; Hero of the Rails onwards; except Tale of the Brave)
- Michael Bideller (Germany)
- Lutz Herkenrath (Germany; Audio Books only)
- Cezary Kwieciński (Poland; Hero of the Rails onwards)
- Reinder van der Naalt (The Netherlands)
- Dov Reiser (Israel; Thomas and the Magic Railroad)
- Dor Srugo (Israel; Tale of the Brave and Sodor's Legend of the Lost Treasure)
- Caspar Phillipson (Denmark)
- Henrique Reis (Brazil; Hero of the Rails onwards)
- Ulisses Bezerra (Brazil; Tale of the Brave only)
- Juan Navarro Torelló (Spain)
- Jukka Voutilaninen (Finland; Hero of the Rails - King of the Railway, thirteenth season - fifteenth season)
- Trưởng Tân (Vietnam)
- Alexander Kotov (Russia)
- Henry has appeared in the Railway Series more than any other engine, having been in both the most books and the most individual stories.
- Henry's LMS Stanier 5MT tender was replaced by a Fowler tender after The Eight Famous Engines in the Railway Series for unknown reasons.
- In the 1997 annual story, We Wish You a Merry Christmas!, Henry's driver was revealed to be named Ted. However, in the magazine story, Henry Helps, Old Bailey is Henry's driver.
- Awdry's own model of Henry was as troublesome as its fictional counterpart; it never really worked properly. The model was eventually scrapped but never replaced.
- One of Henry's models is on display in Japan at the Hara Model Railway Museum(previously at Nitrogen Studios) and is currently wearing his sad face mask.
- Even though by the end of the first season Henry's need for special coal was taken care of, the disposition was strangely reused in Thomas and the Magic Railroad, It's Good to be Gordon and Henry's Happy Coal. King of the Railway eventually put this to rest when Gordon asked if Henry needed "special coal" again and Toby stated the problem was fixed "years ago".
- An ERTL Henry appeared in the American sit-com, Everybody Loves Raymond.
- Henry's whistle sound is actually Edward's and Percy's, but with a lower B flat chime.
- No merchandise line has produced a model of Henry in his original shape, although a prototype was produced for the Thomas Engine Collection Series.
- When nameboards were still used in the series, Henry never had a nameboard shot where he was in his new shape.
- Martin Sherman said in an interview with Sodor Island Fansite, that he originally auditioned to voice Henry, but did get the part for Thomas and Percy instead.
- Henry is one of only three characters, the others being Thomas and James, are the only characters to have at least one line of dialogue in every special. They, along with Gordon, Annie, and Clarabel, are the only characters to appear in every special.
- Henry has been through several aesthetic modifications in the TV series. These include:
- Season 2:
- Regained his wheel arches, which were removed after his rebuild, with the third pair being cut off (from where his tapered firebox was).
- Gained 2 extra brake pipes. In addition, all 4 face downward.
- Season 3:
- His front right and back left brake pipes were facing upward again.
- In Tender Engines, his front left and back right brake pipes were removed.
- Season 5 (only):
- There was extra yellow lining on his half windows at the back of his cab.
- Season 6:
- The lining on his tender was lowered so it no longer lined up with the lining on his cab.
- Season 7:
- His eyebrows became longer.
- Season 10:
- The riveting disappeared from his buffer beam
- Season 12:
- His eyebrows are now thicker
- His crow's feet disappeared.
- Hero of the Rails:
- He lost his front brake-pipe outlet.
- His crow's feet reappeared.
- Season 14:
- The inside of his tender became green.
- Season 17:
- He gained a permanent lamp and tail lamp.
- The Adventure Begins:
- His side-rods became silver.
- Season 2: