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


(Note: * means that an episode has yet to be released on home media in the US).

Screenshot UK title (top)
US title (bottom)
Written by Original UK release date Episode number #
SpringtimeforDiesel.jpg Springtime for Diesel * Davey Moore 18 September 2017 #01
Daisy's springs need fixing after Diesel bumps her and when the rumours spread about Daisy not being able to be mended, Diesel begins to worry.
AMostSingularEngine.jpg A Most Singular Engine * Davey Moore 19 September 2017 #02
Diesel causes trouble between Daisy and Harvey by spreading rumours.
DowagerHatt'sBusyDay.jpg Dowager Hatt's Busy Day * Lee Pressman 20 September 2017 #03
Dowager Hatt runs the railway while Sir Topham is away, but causes confusion and delay.
StuckinGear.jpg Stuck in Gear * Davey Moore 21 September 2017 #04
A branch gets stuck in the gears of Harvey's crane, but he does not want to make a fuss about it.
RunawayEngine.jpg Runaway Engine * Helen Farrall 22 September 2017 #05
After mocking the way she was speaking up for herself, Stephen thinks that Millie ran away after hurting her feelings.
PAProblems.jpg P.A. Problems * Lee Pressman 25 September 2017 #06
The Fat Controller's new public address system causes havoc at Knapford station.
HastyHannah.jpg Hasty Hannah * Lee Pressman 26 September 2017 #07
A new coach temporarily replaces Henrietta while she is at the works.
CrankyattheEndoftheLine.jpg Cranky at the End of the Line * Lee Pressman 27 September 2017 #08
Cranky thinks he will be replaced by a big, new, fancy crane.
NewCraneontheDock.jpg New Crane on the Dock * Lee Pressman 28 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...
UnscheduledStops.jpg Unscheduled Stops * Helen Farrall 29 September 2017 #10
Thomas starts making unscheduled stops for his passengers, which in turn delays others.
Philip'sNumber.jpg Philip's Number * Lee Pressman 2 October 2017 #11
Philip tries to discover why he has the number 68 painted on his side after being teased about it.
TheFastestRedEngineonSodor.jpg The Fastest Red Engine on Sodor * Helen Farrall 3 October 2017 #12
After Rosie is repainted red, she and James have a race.
AShedforEdward.jpg A Shed for Edward * Lee Pressman 4 October 2017 #13
Edward searches for a new shed while his berth at Tidmouth is being repaired.
TheBigFreeze.jpg The Big Freeze Helen Farrall 1 December 2017 #14
When a big freeze hits Sodor, Diesel finally proves himself to be a hero.
EmilyintheMiddle.jpg Emily in the Middle Davey Moore 6 December 2017 #15
Emily gets stuck in the middle while helping Donald and Douglas.
TerenceBreakstheIce.jpg Terence Breaks the Ice Lee Pressman 11 December 2017 #16
Terence takes a shortcut across a frozen lake while collecting Christmas trees.
Daisy'sPerfectChristmas.jpg Daisy's Perfect Christmas Davey Moore 18 December 2017 #17
Daisy is disappointed when her Christmas does not go exactly as planned.
ConfusedCoachespromo.jpg Confused Coaches Helen Farrall 22 December 2017 #18
Spencer and Gordon upset their passengers when their competitive behaviour gets out of hand.


Screenshot Title Composers Original release date
RockyRescue127.png Set Friendship in Motion Kevin Roberge 3 July 2017
You can stay on the tracks
And stand still all day...
DieselandtheDucklings13.png Doing it Right (CGI version) Ed Welch 8 January 2018 (UK; DVD)
Whatever job you're doing,
Make sure you're doing it right...
Toby'sNewFriend50.png Trying (CGI version) Ed Welch 8 January 2018 (UK; DVD)
Anything that Diesels do
Steamies know that they can too...
SamsonatYourService90.png Little Engines (CGI version) Mike O'Donnell
Junior Campbell
19 March 2018 (UK; DVD)
Main Line Engines always boast how big they are,
Superior by far...


Characters Introduced


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 several 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 without Connor.
    • The first series in which where Duck, Caitlin, Rheneas and Mike appear, but do not speak.
    • The first series since their returns in where Bill, Ben, Peter Sam, Butch, Max and Monty appear, but do not speak.
    • The first series in which Hiro, Scruff, Connor, Marion, Samson, Bradford and Hugo do not appear since their introductions.
    • The first series in which Whiff, Oliver, Toad and Alfie do not appear since their return.
    • The first series since the fifteenth not to introduce any new engines.
    • The first series to feature Rosie without her original lavender livery.
    • 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 the twelfth series.
    • The first series where the engines and vehicles perform non-static movements and are able to move their bodies around. This would become more prominent starting with Journey Beyond Sodor.
    • The first series not to have an episode featuring Percy as the main character.
  • This is the only series for a few things:
    • The only series to date where Stafford, Rheneas 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.
    • The last series to use the Engine Roll Call as the title music.
    • The last series to use the newly updated new series theme.
    • 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 members of the Steam Team, as well at the former two as main characters.
    • The final series to have an episode where Thomas isn't featured at all. From the twenty-second series onwards, he appears and narrates every episode (the latter on a permanent basis).
    • The final series where Donald, Douglas, Mavis, Stafford and Rheneas appear to date, but although, Stafford is mentioned in the twenty-fourth series episode, Kenji on the Rails Again.
    • The last series to use the Engine Roll Call on a regular basis.
    • The last series to air on Family Jr. in Canada. Treehouse TV in Canada took over from the twenty-second series onwards.
    • The last series not dubbed in Finnish.
    • The last series to have episodes released on DVD in the United States of America.
    • The last series to air its episodes within one year in the United Kingdom.
  • This is the shortest series of the main series to date, with a total of only 18 episodes. Originally, a full 26-episode series was planned, but eight episodes 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 nineteenth and twentieth series, due to The Adventure Begins being fast-tracked into Arc Productions' schedule. Whilst it has been confirmed that an episode about Rosie's repaint and an episode about Bulgy were going to be part of the series, the nature of the remaining six episodes that were going to be made in this series is currently unknown.

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