The twenty-first season of the television series started airing in the UK on 18th September 2017 and 15th December 2017 for the US.


Screenshot UK title (top)
US title (bottom)
Written by

Original UK
release date

Episode number #
SpringtimeforDiesel "Springtime for Diesel" Davey Moore 18th September 2017 #01
Daisy's springs need fixing after Diesel bumps her.
AMostSingularEngine "A Most Singular Engine" Davey Moore 19th September 2017 #02
Diesel causes trouble between Daisy and Harvey by spreading rumours.
DowagerHatt'sBusyDay "Dowager Hatt's Busy Day" Lee Pressman 20th September 2017 #03
Dowager Hatt runs the railway, while Sir Topham Hatt is away.
StuckinGear "Stuck in Gear" Davey Moore 21st September 2017 #04
A branch gets stuck in the gears of Harvey's crane.
RunawayEngine "Runaway Engine" Helen Farrall 22nd September 2017 #05
Stephen thinks that Millie ran away after hurting her feelings.
PAProblems "PA Problems" Lee Pressman 25th September 2017 #06
The Fat Controller's new public address system causes havoc.
HastyHannah "Hasty Hannah" Lee Pressman 26th September 2017 #07
A new coach temporarily replaces Henrietta while she is at the works.
CrankyattheEndoftheLine "Cranky at the End of the Line" Lee Pressman 27th September 2017 #08
Cranky thinks he will be replaced by a newer, shinier crane.
NewCraneontheDock "New Crane on the Dock" Lee Pressman 28th September 2017 #09
Cranky competes against Carly the new crane when she starts taking all his work.
UnscheduledStops "Unscheduled Stops" TBA 29th September 2017 #10
Thomas starts making unscheduled stops for his passengers, which in turn delays others.
Philip'sNumber "Philip's Number" Lee Pressman 2nd October 2017 #11
Philip tries to discover why he has the number 68 painted on his side after being teased about it.
TheFastestRedEngineonSodor "The Fastest Red Engine on Sodor" TBA 3rd October 2017 #12
After Rosie is repainted red, she and James have a race.
AShedforEdward "A Shed for Edward" TBA 4th October 2017 #13
When Edward's shed is being repaired he is first sent to Philip's shed, then the Steamworks, then Brendam Docks, but they are all too noisy for him to get a good night's sleep!
TerenceBreakstheIce "Terence Breaks the Ice" Lee Pressman 3rd October 2017 #14
Terence takes a shortcut accross a frozen lake while collecting Christmas trees for the holiday market.
Daisy'sPerfectChristmas "Daisy's Perfect Christmas" Davey Moore 3rd October 2017 #15
Daisy is sad when Christmas doesn't go as planned.
ConfusedCoaches "Confused Coaches" Helen Farrall 3rd October 2017 #16
Spencer and Gordon upset their passengers when their competitive behavior gets out of hand.
EmilyintheMiddle "Emily in the Middle" Davey Moore 3rd October 2017 #17
Emily gets stuck in the middle while helping bickering brothers, Donald and Douglas clear away snow.
TheBigFreeze "The Big Freeze" Helen Farrall 3rd October 2017 #18
When a big freeze hits Sodor, Diesel finally proves himself to be a hero.



Characters Introduced





  • Arc Productions had produced the first seven episodes and Terence Breaks the Ice before their bankruptcy.
  • This season contains the 500th episode of the show, which is P.A. Problems.
  • This is the third season not to have Thomas' name titled in any of the episodes, the first being the fifteenth season and the second being the twentieth season.
  • This season marks the first of many things:
    • Ian McCue's first season as creative executive, and the first season to feature him voicing a character.
    • Micaela Winter's first season as producer for the series.
    • Sukhmani Kaur's first season as assistant production manager.
    • Zahara Andrews' first season as production co-ordinator.
    • Alan Kennedy's first season as director of post-production.
    • Ryan Quaglia's first season post-production editor.
    • Gavin Ebedes' first season as supervising editor.
    • Nicola Stapleton's first season as part of the voice cast.
    • Terence, Bulgy and Farmer Finney's first appearances in full CGI.
    • Hackenbeck Tunnel's first appearance in full CGI.
    • Big Mickey gains a face for the first time in the television series.
    • The first season since he became head writer, not to have any episodes written by Andrew Brenner.
    • The first season to have episodes fully animated by Jam Filled.
  • This season also marks the last of several things:
    • Mark Moraghan's last season as narrator for the UK and US dubs.
    • The last season to utilize the original Thomas storytelling format.
    • Boris Andreev's last season as art director.
    • Alan Kennedy's last season as post-production supervisor.
    • Gavin Ebedes' last season as editor.
    • The final season in which the Steam Team consists of all eight of its original members.
    • The final season of the original Thomas & Friends series.
    • The final season to have Edward, Toby and Henry as main characters and members of the Steam Team.
  • This is the shortest season to date, with there only being 18 episodes. There were 26 episodes planned, but eight were cut to make way for the development of Big World! Big Adventures! and Season 22.