With Season 5, the decision was made to write a full series of original, staff-written stories, without using the Railway Series' books as a source. One reason for this was producer Britt Allcroft's desire to create a theatrical Thomas the Tank Engine movie, and requested that director David Mitton show off his modelling skills.
Some inspiration for the episodes came from a former LMR manager named David Maidment. In 1997, Maidment met with Steven Wright about the possibility of supporting the Railway Children charity, and while Wright told him the series' staff commonly received such requests, they would consider. During their meeting, Maidment relayed stories about his railway experiences working in South Wales and as the manager at Crewe station. Maidment received a call asking if he would allow some of his stories to be used as material – the stories from The Railway Series were frequently based on true events, and Allcroft and Mitton preferred this. Maidment agreed, and was also asked to review each story to make sure that the railway in the show operated realistically. As a result, Maidment received writing credit alongside Allcroft and Mitton. 10,000 pounds later was donated to the Railway Children for his work.
The design for each new character would be chosen by David Eves, and given to David Mitton for approval. For ease of filming, Season 5 would introduce larger-scale versions of the narrow gauge engines, and from Season 6-12 these larger models were used almost exclusively. Originally, the character Bertram was supposed to be a tank engine, but financial difficulty in building a new model made them repaint Duke's model with Smudger's face.
|Screenshot|| UK title (top)|
US title (bottom)
|Episode number #|
|"Cranky Bugs"||14th September 1998||#01|
|A new crane called Cranky arrives at the docks and causes trouble for Thomas and Percy. A storm traps the big engines and Duck in the dockyard shed. A tramp steamer runs aground into the quayside, knocking down the shed, and causing Cranky to fall over. In order to rescue the other engines, Cranky needs Thomas and Percy's help.|
|"Horrid Lorry"||15th September 1998||#02|
|Three very Horrid Lorries arrive on Sodor and start taking over the engines' jobs. Percy and Toby receive the worse at the end of the tether. But eventually, the tables are turned, as the lorries get their comeuppance in due course. The engines work even harder to ensure the lorries never return.|
|"A Better View for Gordon"||16th September 1998||#03|
|Gordon complains about the plainness of a new station, and longs for a panoramic view. But over time, he keeps breaking down, and in a way, gets the view he wants, just not the way he was expecting.|
|"Lady Hatt's Birthday Party"||17th September 1998||#04|
|On his way to his wife's birthday, the Fat Controller's car becomes stuck in a pothole. He hitches a lift in Caroline, who breaks down, and then George, who loses control and crashes into a muddy pond. Thomas, luckily, is nearby and the Fat Controller is forced to act as his "relief" fireman to reach the party in time.|
|"James and the Trouble with Trees"||18th September 1998||#05|
|A dirty Thomas is mad at James for boasting about his shiny new coat of paint. James' bragging prevents him from listening to Henry, Percy and Terence's warnings about trees that are too close to the line. Later, James encounters a tree on the line and Thomas comes to his rescue.|
|"Gordon and the Gremlin"||21st September 1998||#06|
|Gordon has problems with his fire and the others joke of gremlins. Although the turntable in the goods yard malfunctions, Gordon manages to get to Kirk Ronan before Thomas to pick up a special visitor. At Wellsworth, the passenger's dog runs away and, after confronting a bull, runs away again into Thomas' cab.|
|"Bye George!"||22nd September 1998||#07|
|George the Steamroller causes a great deal of trouble for the engines. He goes as far as bullying Percy, tarmacking asphalt over the tracks, causing Thomas to crash through a chicken coop, and causes Gordon to crash into one of Duck's trucks. The Fat Controller deals with him after.|
|"Baa!"||23rd September 1998||#08|
|Thomas, Percy and Toby talk about a competition for "The Best Dressed Station" that is being held across Sodor. But as Percy is helping decorate Maithwaite station, a hungry ram is found in the station as decorations are ruined. To everyone's amazement, the ram manages to find the real culprits.|
|"Put Upon Percy"||24th September 1998||#09|
|Percy complains that he is overworked, though the others are unsympathetic. While working at the Coal Mine, some trucks escape from him and they crash inside the mine-shaft, which causes the entire mine to collapse. Percy and his crew try to escape, but are buried underneath coal. Luckily, they are saved by a canvas barrier.|
|"Toby and the Flood"||25th September 1998||#10|
|Heavy storms have been flooding the Island. Toby is sent to inspect the dam, and discovers a few leaks in it. It eventually collapses, causing disaster for a nearby village. He is forced to cross an unsafe bridge over the flooded river, but it breaks and he drifts off towards a waterfall. Harold and Percy are sent to rescue Toby.|
|"Haunted Henry"||28th September 1998||#11|
|Henry refuses to believe in ghosts, until he and his crew encounter a series of spooky events during the night. The trucks tease him, but later down the old line, they become spooked too. In their fright, the trucks surge forward and plunge into a ravine. Henry soon realises that the "ghostly figure" is actually Old Bailey, a friendly fogman.|
|"Double Teething Troubles"||29th September 1998||#12|
|Bill and Ben are worried when they hear that Derek, a malfunctioning diesel, is going to help them work in the clay pits. The twins misunderstand him by thinking he has a toothache. Unfortunately, Derek's "teething troubles" cause more trouble than he is worth.|
|"Stepney Gets Lost"||30th September 1998||#13|
|The Fat Controller invites Stepney to work with Toby and Mavis at the quarry. He impresses everyone so much that the foreman asks Stepney's driver to take a night special. He agrees, forgetting to ask for the Fat Controller's permission. Stepney gets lost on the way home, eventually arriving at the Smelter's Yard.|
|"Toby's Discovery"||1st October 1998||#14|
|Toby takes the Hatts on an expedition, finding a castle and an old mine. The destinations are reopened, but Toby is spooked by Thomas' story about "The Old Warrior", who hunts engines at night.|
|"Something in the Air"||2nd October 1998||#15|
|Based on the magazine story "A Fishy Smell."
Henry is cross when Thomas delays him, and refuses to listen to his warning about a line eroded by high tides. The signalman isn't warned in time, and Henry is sent right down it.
|"Thomas, Percy and Old Slowcoach"||5th October 1998||#16|
|Based on the magazine story "Fire."
Thomas and Percy discover an old coach named Old Slow Coach in the scrapyard, and want to save her. Later, a workman's hut is set on fire, and the workmen have no place to sleep. Percy suggests using Old Slow Coach, and she is soon restored to her former glory.
| "Thomas and the Rumours"|
"Thomas and the Rumors"
|5th October 1998 (VHS)|
6th October 1998 (TV)
|Based on the magazine stories "An Important Visitor" and "Rumours and Speculation".
Thomas sees that a children's playground is closed, but that has to wait as the engines discover that Harold has been hired to show a special visitor around the island. Determined to show how fast he is, Gordon accidentally runs into a tunnel under repair. It turns out that the inspector was really there to find new sand for the children's playground.
|"Oliver's Find"||7th October 1998||#18|
|Oliver is glum only shunting in the yard, and takes it on the trucks, causing an accident. He is put on mail duty instead. A signalman dozes off and they end up going down an old branch line.|
|"Happy Ever After"||8th October 1998||#19|
|Mrs. Kyndley asks Percy and his driver to make a "good luck package" for her daughter's wedding. They agree and slowly find the items as they go about their work.|
|"Sir Topham Hatt's Holiday"||9th October 1998||#20|
|The Fat Controller and his family go on holiday, though things start to go wrong. A low-flying bi-plane named Tiger Moth goes missing, so the Fat Controller and Harold search for it. He decides to go boating on a canal instead, though they become bogged down in mud.|
| "A Surprise for Percy"|
"A Big Surprise for Percy"
|5th October 1998 (VHS)|
12th October 1998 (TV)
|Percy moans about his work in the mines and wants something exciting to happen. His wish comes true when a line of trucks breaks away from him on the hill, and the Fat Controller and Bertie chase them down.|
|"Make Someone Happy"||13th October 1998||#22|
|Thomas tells James to think of others and that he will be much happier if he does. Later, James sees Mrs. Kyndley, who is upset her sister can't come and visitor. A "mystery tour" is arranged for her, and James is chosen for it.|
|"Busy Going Backwards"||14th October 1998||#23|
|Toad confesses to Oliver that he wishes to go forwards for a change, but the trucks are cross and promise to pay him out. On Gordon's Hill, the coupling snaps and Toad goes on a wild ride.|
|"Duncan Gets Spooked"||5th October 1998 (VHS)|
15th October 1998 (TV)
|Duncan teases Peter Sam after some trucks fall into a ravine, so Rusty tells Duncan a ghost story to make him eat his own words. Duncan later has to cross the same ravine.|
|"Rusty and the Boulder"||5th October 1998 (VHS)|
16th October 1998 (TV)
|Rusty is suspicious of a strange boulder lodged in the mountains. A new machine called Thumper comes to work and causes chaos when he dislodges the boulder and it lets loose on the railway.|
|"Snow"||5th October 1998 (VHS)|
19th October 1998
|Thomas is cross with the snow, so Rusty tells him about Skarloey's own experience. His crew had stopped on the line to have some cocoa, but some slate trucks run through the buffers and into the ravine, causing an avalanche.|
- Bill and Ben
- Annie and Clarabel
- S. C. Ruffey
- Sir Topham Hatt
- Lady Hatt
- Stephen Hatt
- Bridget Hatt
- Jem Cole
- Mrs. Kyndley
- Peter Sam (does not speak)
- Henrietta (does not speak)
- Donald (cameo)
- Trevor (cameo)
- The Refreshment Lady (cameo)
- Nancy (cameo)
- Tom Tipper (cameo)
- Wilbert Awdry (music video cameo)
- Douglas (music video cameo)
- Diesel (music video cameo)
- Daisy (music video cameo)
- The Diesel (music video cameo)
- Sir Handel (music video cameo)
- Duke (music video cameo)
- Bulstrode (music video cameo)
- Bulgy (music video cameo)
- Old Slow Coach
- The Horrid Lorries
- Old Bailey
- Dowager Hatt
- Derek (not named)
- 'Arry (not named)
- Bert (does not speak)
- The Ghost Engine (does not speak)
- Bertram (does not speak)
- Butch (does not speak)
- Thumper (does not speak)
- Tiger Moth (does not speak)
- This was the first season of several things:
- The first season not to have any episodes based on The Railway Series stories by Wilbert and Christopher Awdry.
- The first season to introduce original characters not created by Wilbert or Christopher Awdry.
- Alec Baldwin's first season as narrator.
- The first season not to air on Shining Time Station due to the show ending. Episodes from Season 5 were instead aired on FOX Family's Storytime with Thomas and PBS Kids Sprout
- The first season to use a Proteus 2000 to compose the music.
- The first season not dubbed in Finnish or Ukrainian.
- The first season to air in Canada.
- The first season in which Douglas does not appear since his debut in the second season. Although, he does appear in a music video from this season.
- The first season in which the phrase, "confusion and delay" is said.
- According to an interview with David Mitton before his death in 2008, this season was supposed to be a showcase of Thomas and the Magic Railroad.
- Production of this season began after Wilbert Awdry died in March 21st, 1997, but ended sometime in the later half of either 1997 or 1998.
- This season features the most songs, at a total of ten.
- This was also the final season of several things:
- Britt Allcroft's final season as writer and producer.
- David Mitton's final season as producer.
- Angus Wright's last season as executive producer.
- The last season to premiere in the UK on Cartoon Network.
- The last season filmed completely in 4:3 full screen.
- The last season shown in Germany and Spain.
- The last season to have a railway consultant.
- The last season to feature appearances of BoCo.
- The last season where characters said the word "stupid".
- This was also the only season of several things:
- The only season not to feature Knapford Station.
- The only season to feature Kirk Ronan.
- The only season that Diesel does not appear in since his debut in the second season, though he does appear in a music video from this season.
- David Maidment's only season as railway consultant and writer.
- The only season where Donald appears, without Douglas.
- The only season where Donald appears, but doesn't speak.
- The only season to feature appearances of Old Slow Coach, the Horrid Lorries, Old Bailey, the Special Visitor, Mrs. Kindley's daughter, Bertram, Rusty's Ghost Engine, Thumper, and Harry Topper.
- The only season recorded in Dolby Surround Sound, hence the absence of certain sound effects and music in either the UK or US version of several episodes.
- Michael Angelis was not credited in the opening titles for the UK narration. However, he is credited as narrator in the Hindi narration, even though it was redubbed.
- This season's official episode order differs from the aired order.