Harold is a helicopter who patrols the Island of Sodor, searching for emergencies. He is part of the Search and Rescue Team. He is operated by two pilots.
The Railway Series
When Harold first met Percy, he stated that railways were "slow and out-of-date", but was proven wrong when Percy beat him in a race. When Thomas' brakes failed while boarding at a station, with an inspector Harold chased him down the line. For Christmas that year Harold brought Father Christmas to the party at Tidmouth Station. Harold also dropped hot drinks for Percy's crew when they were stranded in a floating river.
Thomas & Friends
He became friends with Duck after rescuing an injured sailor.
Harold used to live at Dryaw Airfield by Thomas' Branch Line. He keeps a watchful eye over Sodor in case of trouble and speeds to the rescue of anyone in distress.
As of Misty Island Rescue, he joined the Sodor Search and Rescue team and lives in his own hangar at the Sodor Search and Rescue Centre. Since joining the team he has been involved in a search for Thomas when he got lost, saving Bertie from the Shake Shake Bridge and helping Charlie to recapture an elephant which escaped from the Sodor Animal Park. Once, Harold's rotors became jammed, so Thomas and Duck took him to the Sodor Search and Rescue Centre.
He and the rest of the rescue team helped out after a big storm and they were rewarded with a new alarm bell for the rescue centre. He later found Percy and Diesel trapped in a flood at the Old Quarry and the rescue team helped them out. He also helped The Duke and Duchess of Boxford get to Callan Castle, after Thomas, Spencer and Bertie failed.
In the twentieth series, he and Percy's rivalry resurfaced at Christmas. Percy was struggling to get through the snow while delivering mail for Santa, so Harold offered to help, but Percy refused. Percy then left behind a sack of letters at Dryaw and Harold decided to get them to him. Percy, believing Harold was mocking his speed again, decided to race him, only to crash into a snowdrift. Harold again offered to help deliver the mail and this time, Percy agreed. While he was able to deliver the mail to Hiro, he ran out of fuel and was grounded in a field on the Mainland for the night. When Percy found out, he raced off to find him and then brought him some fuel, not wanting him to spend Christmas alone and believing "one good turn deserves another". The two friends then returned to Sodor.
Thomas and the Magic Railroad
Harold flew by at Tidmouth Sheds, spreading sneezing powder all over Thomas, Splatter and Dodge. In earlier scripts, he did not speak and he spread quarry dust in the quarry bowl all over Thomas, Splatter, and Dodge.
When Harold was first introduced, he was shown is very proud of being able to fly, and the speed and versatility this gives him. He somewhat tended to be cocky, as he believed that "railways are slow and quite out of date". This caused a bit of rivalry between him and the engines, particularly Percy, and he is usually nicknamed "whirlybird" for that, but he usually got his comeuppance in the end. Sometimes, he finds himself in need of Percy's help after he teases him for being slow. Despite this, he still works hard and deep down, he knows that the engines on the Fat Controller's railway, including Percy, are just as useful as he is. He is always helpful and highly alert whenever there is an emergency, especially on patrol. Because of this, he remains a friend to the railway.
However, since he joined the Sodor Search and Rescue Centre, he has acted a lot more mature and almost never teases the engines. He takes his job as part of the team very seriously and continues to remain on patrol.
Harold also speaks in a manner reminiscent of an RAF pilot, using terms such as "wizard" and "old chap" in conversation.
Harold is based on a Sikorsky S-55 helicopter (also known as Sikorsky H-19 Chickasaw), built in the UK as the Westland Whirlwind. He has added floats. Around 70 of these still survive in some form.
Harold is painted white with red lining. His name is painted on his sides, near his tail, in red.
The Railway Series
- Percy the Small Engine - Percy and Harold and Percy's Promise (does not speak)
- More About Thomas the Tank Engine - The Runaway
- Thomas Comes Home - Snow Problem (does not speak)
- Thomas and the Missing Christmas Tree (does not speak)
Thomas & Friends
- Series 2 - Percy and Harold, The Runaway and Thomas and the Missing Christmas Tree (does not speak)
- Series 3 - Percy's Promise, Thomas, Percy and the Post Train, All at Sea and Thomas and Percy's Christmas Adventure
- Series 4 - Trucks
- Series 5 - Baa! (does not speak), Toby and the Flood, Thomas and the Rumours (does not speak), Oliver's Find, Sir Topham Hatt's Holiday and Make Someone Happy
- Series 6 - A Bad Day for Harold the Helicopter and Percy's Chocolate Crunch
- Series 7 - Emily's New Coaches (cameo), Harold and the Flying Horse, The Grand Opening (does not speak), Best Dressed Engine (cameo) and Three Cheers for Thomas
- Series 8 - Don't Tell Thomas
- Series 9 - Thomas and the Rainbow (does not speak), The Magic Lamp and Bold and Brave
- Series 10 - Topped Off Thomas (does not speak), Thomas and the Birthday Mail and Thomas and the Treasure
- Series 12 - Henry Gets it Wrong and James Works it Out
- Series 14 - Henry's Health and Safety (cameo), Being Percy (cameo), Jumping Jobi Wood! (does not speak), Jitters and Japes (cameo) and Merry Misty Island
- Series 15 - Toby and Bash (cameo), Edward the Hero, James to the Rescue (cameo), Happy Hiro (cameo), Henry's Happy Coal (cameo), Let it Snow, Stop That Bus!, Stuck on You and Fiery Flynn (cameo)
- Series 16 - Race to the Rescue (cameo), Express Coming Through (does not speak), Sodor Surprise Day (does not speak) and Welcome Stafford (cameo)
- Series 17 - Not Now, Charlie!, The Thomas Way and Too Many Fire Engines (does not speak)
- Series 18 - Duck in the Water (does not speak), Thomas and the Emergency Cable (mentioned) and Last Train for Christmas (does not speak)
- Series 19 - Toad and the Whale, Helping Hiro, Two Wheels Good, Rocky Rescue, The Other Side of the Mountain (does not speak) and Wild Water Rescue
- Series 20 - Letters to Santa and Skiff and the Mermaid
- Series 21 - The Fastest Red Engine on Sodor (cameo) and Daisy's Perfect Christmas
- Series 23 - Panicky Percy, Steam Team to the Rescue! and Deep Trouble
- Series 24 - A New Arrival, The Inventor's Spectacular Bridge and Nia's Bright Idea
- Other - Thomas & Friends in 4-D: Bubbling Boilers (does not speak)
He may appear in the twenty-fourth series.
- 1992 - Thomas and the U.K. Trip (cameo)
- 2000 - Thomas and the Magic Railroad
- 2005 - Calling All Engines! (does not speak)
- 2008 - The Great Discovery
- 2010 - Misty Island Rescue
- 2011 - Day of the Diesels (cameo)
- 2013 - King of the Railway (does not speak)
- 2016 - The Great Race (rotor blades only)
- 2018 - Big World! Big Adventures!
- Series 8 - Sounds (does not speak)
- Series 9 - Percy in the Dark (does not speak; UK version only), Arthur's Tricky Travels (does not speak), Sir Topham Hatt's Helping Hand (does not speak), What is Thomas Thinking? (does not speak) and What does Toby see? (does not speak)
- Series 10 - Who Can Take Them? (does not speak) and What Does Harold See? (does not speak)
- 1988 - Thomas and Harold, Percy and Harold and The Runaway
- 1989 - Hurricane!, Diesel's Christmas (does not speak) and An Important Visitor (cameo)
- 1990 - Rumours and Speculation (does not speak)
- 1992 - James's Task
- 1996 - Night Lights (does not speak)
- 1997 - Star Story! and Thomas, Percy and the Post Train
- 1998 - Really Useful Rusty!, The Exhibition! (mentioned) and The Beached Whale!
- 1999 - Thomas is Rescued (does not speak) and Harold and Henry
- 2000 - A Special Story About Harold (does not speak), Harold's Race!, Harold's View, Wet Wheels (mentioned)and Painting the Shed (cameo)
- 2001 - The Eyesight Test (mentioned), A Special Story About Harold, The Kite Contest, Harold Goes Quiet, Airborne Engine and Eye-in-the-Sky
- 2002 - Henry (cameo), Sodor Goes Pop!, Safe as Houses!, A Snowy Reception and Climb Time!
- 2003 - False Alarm, Harold's Bad Day, Henry's Dizzy Day, Surprise, Surprise!, Mountain Rescue, Queen of the Road!, Super Heroes! (does not speak), Flying Fish! (cameo), Broken Bridges (cameo), Cruise Control! (does not speak), Really Fast Food!, Percy the Post!, Happy and Sad (cameo), Air Share! and Animals (does not speak)
- 2004 - Pony Pick-Up!, Harold's Bad Day, Going for a Swim!, Special Signal, Henry to the Rescue (does not speak), Dirty Percy!, The Grand Opening (does not speak), Holiday Hat (cameo), Dockers' Dinner (cameo), Emily Saves Henry (cameo), Night Lights (cameo), Sound of Silence, Proud and Loud (cameo), Harold to the Rescue, Glider Rider (does not speak) and The Flying Horse
- 2005 - Mine Mystery (cameo), Tidy-Up Time! (cameo), A Treat for Trying (cameo), Tunnel Trouble and Naughty or Nice?
- 2006 - Monster Mistake (does not speak), Caroline's Cruise, Passenger Plane, Sparkling Sky, Old and Useful(cameo), Harold's Holiday and Disgusted Diesels
- 2007 - Airship (does not speak), Autumn Leaves (does not speak), Blown About!, The Telescope (does not speak), Rusty's Rescue!, Playful Passengers (cameo) and Henry's Hairy Passenger (cameo)
- 2008 - Snow Trouble!, Mystery Music (cameo), Big is Beautiful, Percy's Post!, Just in Time (does not speak), Stop, Thief! (cameo) and Come Back, Please! (does not speak)
- 2009 - New Delivery (cameo)
- 2010 - Henry Gets It Wrong! (does not speak), Harold Afloat, Misty Island Rescue (cameo), Saving Santa!, Thomas Takes Off!, Thomas and the Rainbow! (does not speak), In a Spin and Disgusted Diesels (cameo)
- 2011 - Racing on the Rails, Monster Mistake (does not speak), Misty Island Rescue (cameo), Rosie's Rocks, Harold and the Kites, Pictures in the Sky (cameo), Splashdown!, Tidy Thomas (cameo) and Playful Passengers(cameo)
- 2012 - Edward the Hero (does not speak), Operation Rescue, The Fat Controller's Bedtime Story (Issue 639)(does not speak), Making Hiro Happy (cameo), Where's That Bus?, Happy Harold, Carol Concert, Clock Countdown, A Musical Mystery (cameo), Playful Passengers! (cameo) and The New Delivery (cameo)
- 2013 - Hover Bother!, Sodor Surprise Day (does not speak), Henry's Scary Passenger! (cameo), Toby to the Rescue and All in a Day's Rescue (mentioned)
- 2014 - The Thomas Way (does not speak), Kite Flying (does not speak), William's Wish, Edward the Helpful Engine(mentioned) and Not Now, Charlie! (does not speak)
- 2015 - Duck in the Water (speaks in speech bubble only) and Not Now, Charlie! (does not speak)
- 2017 - Not Now, Charlie! (does not speak)
Harold also appeared in the magazine stories, Bright Sight, Company for Cranky, Fishy Diesel!, Harold and the Broken Tree, Lost Luggage!, On Inspection, Percy's Plight, Ride and Slide, Sky High!, Smoke Signals, Smoky Sky, Sodor Goes Pop!, Sound of Silence, Steaming Along!, Stone Signal, The Best Band, The Great Air Race, The Great Statue Robbery, The Lighthouse Light and The Trainspotters
- 1989 - Post Early for Christmas (does not speak) and Harold and the Landslide
- 1994 - Better Safe than Sorry
- 1996 - All Pull Together
- 1998 - The Star of the Show
- 1999 - Leaves on the Line (does not speak)
- 2001 - Very Special Engines (cameo)
- 2002 - Harold the Helicopter
- Where in the World is Thomas? (partially performed)
- Kevin Frank (Thomas and the Magic Railroad)
- Keith Wickham (UK; Misty Island Rescue onwards, excluding Big World, Big Adventures)
- Kerry Shale (US; Misty Island Rescue onwards, UK; Big World, Big Adventures singing voice only)
- Gerald Schaale (Germany; Thomas and the Magic Railroad)
- Kai-Hendrik Möller (Germany; Misty Island Rescue - sixteenth series)
- Burkhard Schmeer (Germany; seventeenth series onwards)
- Thorsten Weber (Germany; Audio Book 4 only)
- Philipp Schmidt (Germany; Audio Book 8 only)
- Yūki Satō (Japan; second - eighth series)
- Wataru Hatano (Japan; Calling All Engines! onwards, excluding Big World! Big Adventures!)
- Nozomu Sasaki (Japan; Big World! Big Adventures! only)
- Christoffer Staib (Norway; Misty Island Rescue - fifteenth series)
- TBA (Norway; seventeenth series onwards)
- Waldemar Barwiński (Poland; Misty Island Rescue onwards)
- Alexander Heeren (The Netherlands)
- Edson Matus (Latin America; Thomas and the Magic Railroad)
- Jorge Santos (Latin America; Thomas and the Magic Railroad; TV Version)
- Daniel del Roble (Latin America; Misty Island Rescue onwards)
- Aryeh Cherner (Israel; Thomas and the Magic Railroad)
- TBA (Israel; Misty Island Rescue - fourteenth series)
- Nir Ron (Israel; fifteenth - seventeenth series)
- TBA (Israel; nineteenth series onwards)
- Juan Navarro Torelló (Spain)
- Tony Marot (France and French speaking Canada; sixth series onwards)
- Petri Hanttu (Finland; Misty Island Rescue onwards)
- Haris Grigoropoulos (Greece)
- One of Harold's models is on display in Japan at the Hara Model Railway Museum (previously on display at Nitrogen Studios in Canada).
- Harold has gone through several changes throughout the Television Series:
- Series 2:
- His spinning rotors were achieved using a transparent disk.
- In "Percy and Harold", "The Runaway" and "Thomas and the Missing Christmas Tree", he is shown with a lamp.
- Series 3:
- His model's blades now spin when shown flying.
- His blades become flimsy and slightly bent.
- The lamp reappears only in Thomas, Percy and the Post Train.
- Series 4:
- His blades become straight again.
- Series 5:
- His blades go back to being flimsy and bent.
- Thomas and the Magic Railroad:
- His blades are straight once again.
- Series 8:
- The lamp becomes permanent.
- Series 10:
- His eyes now move with a motor.
- Series 12:
- He becomes rendered in full CGI.
- His red lining becomes a darker shade of red.
- Misty Island Rescue:
- His main body becomes smaller.
- His face becomes smaller and lowered slightly.
- His lining changed back to the red shade it normally was.
- Series 2:
- In both of his appearances in the sixth series, Harold's unhappy expression was always visible behind his mouth on his happy face.
- Harold's theme in the second series is a musical variation on the main score of the 1955 film, The Dam Busters.
- The fifteenth series episode Stop That Bus! was the first time Harold has flown outside of The Island of Sodor.
- In the television series, Harold has never had eyebrows. However, he did have them in the magazine stories Mountain Rescue and False Alarm and in illustrations by Ken Stott.
- Harold was called Herbert in the French dub from the second to seventh series.
- One of Harold's Wooden Railway toys appears in an episode of CW's show Smallville entitled "Nicodemus".
- Despite having floats with fitted wheels, Harold has never been seen floating or being rolled.
- "Hello," said Percy, "Who are you?"
- "I'm Harold. Who are you?"
- "I'm Percy. What whirley great arms you've got!"
- "They're nice arms!" said Harold, offended. "I can hover like a bird. Don't you wish you could hover?"
- "Certainly not! I like my rails, thank you".
- "I think railways are slow!" said Harold in a bored voice. "They're not much use and quite out of date".
- A conversation between Percy and Harold in Percy and Harold, Percy the Small Engine.
- The engines were just leaving the station, when they heard a familiar buzzing.
- "I say you two, there's news flying about!"
- "Where?" puffed Percy.
- "All over the place. They're going to scrap the Post Train/the Mail Train and use me instead. Wings work wonders you know! Always!"
- "Rubbish!" huffed Thomas.
- Harold boasting to Thomas and Percy in Thomas, Percy and the Post Train.
- Merit (Pull-Along)
- ERTL (normal and Gold Rail; both discontinued)
- Wooden Railway (normal and with magnet; discontinued)
- Take Along (normal and with magnet; discontinued)
- Take-n-Play (discontinued)
- Motor Road and Rail (discontinued)
- TrackMaster (discontinued, reintroduced in 2015 and 2020 in set only; both discontinued)
- My First Thomas (normal and talking; discontinued)
- Lionel (discontinued)
- Thomas Engine Collection Series (discontinued)
- Mini Die Cast Collection (discontinued)
- Thomas Town (discontinued)
- Capsule Collection
- Trading Cards (discontinued)
- Mega Bloks (discontinued)
- My Thomas Story Library (discontinued)
- Engine Adventures (discontinued)
- Wind-up (normal and metallic)
- Limited Edition Collection
- Pocket Fantasy (discontinued)
- Discover Junction
- LEGO (discontinued)
- Collectible Railway
- Push Along
- Micro Rubber Engines
- Pico Pico
- Boss (discontinued)
- De Agostini (discontinued)
- Motorized Railway
- Choro-Q (discontinued)
- New Block
- Pre-Cut Model Engine Books (discontinued)
- Royal Hampshire (discontinued)
- Big Buddy (discontinued)
- Adventures (discontinued)
- My First Thomas & Friends
- TrackMaster Push Along
- Classic Minis
- Spring Minis
- Aquarium Minis (coming soon)