The sixth season of the television series aired in 2002. Michael Angelis and Alec Baldwin narrated the twenty-six episodes for the UK and US respectively. Michael Angelis also narrated two episodes for the US release of New Friends for Thomas and Other Adventures. Michael Brandon later re-dubbed six episodes for the US.
- Salty's Secret - Salty is dismayed when he is sent to work at the quarry.
- Harvey to the Rescue - The engines tease Harvey for his unusual appearance, but he soon proves his worth.
- No Sleep for Cranky - Cranky is in a worse mood than ever when he is stuck with Salty, Bill and Ben for the night.
- A Bad Day for Harold the Helicopter/A Bad Day for Harold - Percy is stuck at a broken signal and Harold takes the mail all at once - with disastrous results.
- Elizabeth the Vintage Lorry/Elizabeth the Vintage Quarry Truck - When Thomas breaks down near an old shed, he discovers a disused lorry named Elizabeth.
- The Fogman - Ordinarily, Cyril, the fogman, warns the engines that there is fog ahead in Misty Valley, but The Fat Controller replaces him with a fog horn.
- Jack Jumps In - Jack the front loader is eager to be really useful, but soon learns his mistake.
- A Friend in Need - Jack tries to prove his worth after Ned nearly causes an accident with the bridge.
- It's Only Snow - Thomas encounters trouble in the snow with his faulty snowplough.
- Twin Trouble - Donald and Douglas fall out after an accident.
- The World's Strongest Engine - Diesel returns and tries to prove that diesels are stronger than steam engines.
- Scaredy Engines - Thomas teases Percy, but when they're sent to the Smelters to collect a special load Thomas gets his just desserts.
- Percy and the Haunted Mine - Percy is spooked by a mine that sinks into the ground.
- Middle Engine - 'Arry and Bert play tricks on Percy and James by shunting trucks in front of them.
- James and the Red Balloon - Thomas and James are scared a hot air balloon will steal their passengers.
- Jack Frost - James is frightened when he sees a snowed-under Percy and mistakes him for Jack Frost.
- Gordon Takes a Tumble - Salty gives Gordon advice, but Gordon refuses to listen.
- Percy's Chocolate Crunch - Percy complains when he is restricted to one washdown a day, but gets dirtier than ever when he takes a load to the chocolate factory.
- Buffer Bother - Bill is jealous when Ben gets brand-new buffers.
- Toby Had a Little Lamb - Duck is unable to get to Farmer McColl's Field during winter, so Toby must rescue the lambs.
- Thomas, Percy and the Squeak - Thomas is proud when he gets to transport the famous singer Alicia Botti instead of Percy, but soon learns his lesson.
- Thomas the Jet Engine/Thomas and the Jet Engine - Gordon boasts about being the fastest engine on Sodor, but Thomas soon proves him wrong.
- Edward the Very Useful Engine/Edward the Really Useful Engine - Edward is old, but that doesn't stop him from helping Gordon and Duck.
- Dunkin Duncan - Duncan gets too impatient at the incline and ends up falling into a muddy ditch.
- Rusty Saves the Day - Rusty helps mend Rheneas and Skarloey's line, with Elizabeth's help.
- Faulty Whistles - Duncan loses his whistle and the replacement is very musical.
- Donald and Douglas
- Bill and Ben
- 'Arry and Bert
- Peter Sam
- Sir Topham Hatt
- Stephen Hatt (not named)
- Stepney (does not speak)
- Annie and Clarabel (do not speak)
- Henrietta (does not speak)
- Terence (does not speak)
- Jem Cole (does not speak)
- Oliver (cameo)
- George (cameo)
- Tiger Moth (cameo)
- Bridget Hatt (cameo)
- Dowager Hatt (cameo)
- Mrs. Kyndley (cameo)
- Farmer Trotter (cameo)
- The Refreshment Lady (cameo)
- Nancy (cameo)
- The Storyteller (cameo)
- The Tailor (cameo)
- The Dryaw Policeman (cameo)
- Bulgy (mentioned)
- BoCo (music video cameo)
- Sir Handel (music video cameo)
- Duke (music video cameo)
- Bulstrode (music video cameo)
- The Chinese Dragon (music video cameo)
- Toad (deleted scene cameo)
- Oliver the excavator
- Jenny Packard
- The Foreman
- Cyril the Fogman
- Headmaster Hastings
- Alicia Botti
- Farmer McColl (not named in original versions)
- The Fisherman (cameo)
- This was the first season of several things:
- The first season to be filmed in 16:9 widescreen. However, most of the first six episodes were matted from full screen.
- Phil Fehrle's first season as producer.
- Peter Urie's first season as executive producer.
- Abi Grant's first season as script editor.
- The first season to feature Steve Asquith as a director.
- The first season to have multiple directors.
- The first season not to be dubbed in Dutch, German, Greek and Portuguese.
- This was the last season of several things as well:
- This season had its own special intro.
- This season has more narrators than any other.
- From this season onwards, all stories were written by individuals on a writing staff.
- In 2005, Michael Angelis renarrated some episodes from this season with new music by Robert Hartshorne.
- Despite being made in 2002, this season was not broadcast on Citv until early 2003.
- This is the only season where Oliver appears without Toad (not counting music videos). It is also the only season where he does not have any speaking roles.