The twenty-first series of Thomas & Friends started airing on September 18, 2017. It is the shortest series to date with 18 episodes, and was narrated by Mark Moraghan.


Screenshot UK title (top)
US title (bottom)
Written by Original UK release date Episode number #
SpringtimeforDieselSpringtime for DieselDavey Moore18 September 2017#01
Daisy's springs need fixing after Diesel bumps her, and when the rumors spread about Daisy not being able to be mended, Diesel begins to worry.
AMostSingularEngineA Most Singular EngineDavey Moore19 September 2017#02
Diesel causes trouble between Daisy and Harvey by spreading rumors.
DowagerHatt'sBusyDayDowager Hatt's Busy DayLee Pressman20 September 2017#03
Dowager Hatt runs the railway while Sir Topham is away, but causes confusion and delay.
StuckinGearStuck in GearDavey Moore21 September 2017#04
A branch gets stuck in the gears of Harvey's crane, but he doesn't want to make a fuss about it.
RunawayEngineRunaway EngineHelen Farrall22 September 2017#05
After mocking the way she was speaking up for herself, Stephen thinks that Millie ran away after hurting her feelings.
PAProblemsP.A. ProblemsLee Pressman25 September 2017#06
The Fat Controller's new public address system causes havoc at Knapford station.
HastyHannahHasty HannahLee Pressman26 September 2017#07
A new coach temporarily replaces Henrietta while she is at the works.
CrankyattheEndoftheLineCranky at the End of the LineLee Pressman27 September 2017#08
Cranky thinks he will be replaced by a big, new, fancy crane.
NewCraneontheDockNew Crane on the DockLee Pressman28 September 2017#09
Cranky competes against Carly the new crane when she starts taking all his work, and both of them get quite the surprise at the end of the day...
UnscheduledStopsUnscheduled StopsHelen Farrall29 September 2017#10
Thomas starts making unscheduled stops for his passengers, which in turn delays others.
Philip'sNumberPhilip's NumberLee Pressman2 October 2017#11
Philip tries to discover why he has the number 68 painted on his side after being teased about it.
TheFastestRedEngineonSodorThe Fastest Red Engine on SodorHelen Farrall3 October 2017#12
After Rosie is repainted red, she and James have a race.
AShedforEdwardA Shed for EdwardLee Pressman4 October 2017#13
Edward searches for a new shed while his berth at Tidmouth is being repaired.
TheBigFreezeThe Big FreezeHelen Farrall1 December 2017#14
When a big freeze hits Sodor, Diesel finally proves himself to be a hero.
EmilyintheMiddleEmily in the MiddleDavey Moore6 December 2017#15
Emily gets stuck in the middle while helping Donald and Douglas.
TerenceBreakstheIceTerence Breaks the IceLee Pressman11 December 2017#16
Terence takes a shortcut across a frozen lake while collecting Christmas trees.
Daisy'sPerfectChristmasDaisy's Perfect ChristmasDavey Moore18 December 2017#17
Daisy is disappointed when her Christmas does not go exactly as planned.
ConfusedCoachespromoConfused CoachesHelen Farrall22 December 2017#18
Spencer and Gordon upset their passengers when their competitive behaviour gets out of hand.




Characters Introduced

Introduced in Big World! Big Adventures!


UK, AUS and NZ

US and CAN


  • Arc Productions had produced the first seven episodes and Terence Breaks the Ice before their bankruptcy.
  • This series contains the 500th episode of the show, P.A. Problems.
  • This is the third series not to have Thomas' name titled in any of the episodes, the first being the fifteenth series and the second being the twentieth series.
  • This series marks the first of many things:
    • The first series to have no episodes written by Andrew Brenner during his tenure as head writer.
    • The first series to be produced by Mattel Creations.
    • Ian McCue's first series as creative executive and the first series to have him as part of the voice cast.
    • Micaela Winter's first series as producer for the series.
    • Sukhmani Kaur's first series as assistant production manager.
    • Zahara Andrews' first series as production co-ordinator.
    • Alan Kennedy's first series as director of post-production.
    • Ryan Quaglia's first series as post-production editor.
    • Gavin Ebedes' first series as supervising editor.
    • Terence, Bulgy and Farmer Finney's first appearances in full CGI.
    • Hackenbeck Tunnel, Terence's Field, and Suddery Junction's first appearance in full CGI.
    • Big Mickey's first appearance with a face in the television series.
    • The first series where Caitlin appears, but without Connor who does not appear since his introduction in King of the Railway.
    • The first series in which Hiro does not appear since his introduction in Hero of the Rails.
    • The first series in which Scruff does not appear since his introduction in the fourteenth series.
    • The first series in which Oliver and Toad do not appear since their returns in the eighteenth series.
    • The first series in which Samson does not appear since his introduction in the eighteenth series.
    • The first series since the fifteenth not to introduce any new engines.
    • The first series since the sixteenth to have all of its episodes released in the same year.
    • The first series to have episodes fully animated by Jam Filled.
    • The first series not to be dubbed in Dutch since Series 12.
  • This is the only series for a few things:
    • The only series to date in where Duck, Caitlin, Stafford, Rheneas, Mike and Oliver the Excavator appear, but do not speak since their introductions or reintroductions respectively. 
    • The only series to date in which Farmer Finney has a speaking role.
  • This series also marks the last of several things:
    • Mark Moraghan's last series as narrator for the UK and US dubs.
    • The last series to utilise the original storytelling format.
    • Boris Andreev's last series as art director.
    • Alan Kennedy's last series as post-production supervisor.
    • Gavin Ebedes' last series as editor.
    • The last series to have Helen Farrall as part of the writing team.
    • The final series in which the Steam Team consists of all eight of its original members.
    • The final series to have Edward, Henry and Toby as main characters and members of the Steam Team.
    • The final series to have an episode where Thomas does not appear at all. From the twenty-second series onwards, he appears and narrates every episode.
    • Currently, the final series where Donald, Douglas and Mavis appear.
    • The last series to use the Engine Roll Call on a regular basis.
    • The last series to be aired on Family Jr. in Canada. Treehouse TV in Canada took over from Series 22 onwards.
    • The last series not dubbed in Finnish.
  • This is the shortest series of the main series to date, with a total of only eighteen episodes. Originally, a full 26-episode series was planned, but eight were cut to make way for the development of Big World! Big Adventures! and the twenty-second series. In addition to this, Sodor Island Forums confirmed that the reduced total of episodes was needed to make up for the delayed productions of the nineteeth and twentieth series, due to The Adventure Begins being fast-tracked into Arc Productions' schedule.

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