第 21 季 共 18 集
播出时间：2017年9月19日
第 1 集 Springtime for Diesel
播出时间：2017年9月19日
Diesel is always bumping into people and laughing, but when he does it to Daisy, her springs need fixing. In the Dieselworks, thinking that she is asleep, Diesel explains why he did it - it's his way of trying to make friends!
第 2 集 A Most Singular Engine
播出时间：2017年9月20日
Diesel makes mischief between Daisy and Harvey by telling them both that the other is boasting of being unique. However, the two become friends while assisting each other on a job, and Diesel does not understand why.
第 3 集 Dowager Hatt's Busy Day
播出时间：2017年9月21日
While the Fat Controller is sick, his mother runs the railway and creates chaos by getting everyone to do the wrong jobs! Oblivious to all the mayhem, Dowager Hatt supervises the hanging baskets at Knapford Station - until Emily gets involved.
第 4 集 Stuck in Gear
播出时间：2017年9月22日
A branch gets stuck in the open gears of his crane, but Harvey is too shy to ask for help. Instead, he tries to fix it himself and ends up derailing himself inside a tunnel.
第 5 集 Runaway Engine
播出时间：2017年9月23日
Millie is given extra work around the estate and gets agitated when Stephen and Glynn forget to clear up the garden waste. When Stephen also manages to hurt her feelings, and can't find her the next day to apologise, he thinks that she must have run away.
第 6 集 P.A. Problems
播出时间：2017年9月26日
The Fat Controller splashes out on a new public address system, but the engines and passengers are struggling to hear the announcements. Holidaymakers end up at the quarry, quarry workers end up at the beach and Lord Callan ends up with an unexpected delivery of pigs!
第 7 集 Hasty Hannah
播出时间：2017年9月27日
While Henrietta is getting her seats refurbished, Toby is given a replacement carriage named Hannah. However, she is so headstrong and reckless that Toby gets fed up with her urging him to go faster and faster. But when he abandons her and she joins up with James, she learns to her cost that going too fast for a little carriage is not at all wise.
第 8 集 Cranky at the End of the Line
播出时间：2017年9月28日
After Cranky is teased about his age, he works twice as hard and through the night to impress the Fat Controller. But the harder he works, the more mistakes he makes. When a big, new, shiny crane arrives, he thinks that his days at Brendam Docks are over!
第 9 集 New Crane on the Dock
播出时间：2017年9月29日
Carly the new crane is so keen that she takes on all the work. After Cranky finds himself with nothing to do, he works harder and faster in a bid to keep up with her. But as the two cranes frantically try to outdo one another, their hooks become entangled and they find themselves stuck fast and unable to move...
第 10 集 Unscheduled Stops
播出时间：2017年9月30日
When Bertie breaks down while they are racing, Thomas takes on his passengers. One elderly man says that Bertie always drops him off between stops. Soon Thomas is getting requests for lots of other unscheduled stops, which makes him run late and upsets his own passengers and the Fat Controller.
第 11 集 Phillip's Number
播出时间：2017年10月3日
When he is teased about having 68 painted on his side, Philip tries to discover why he was given that number. Later, when he manages to avoid an accident after 68 sheep stray onto the line, Philip decides it is his lucky number!
第 12 集 The Fastest Red Engine on Sodor
播出时间：2017年10月4日
When Rosie is painted red she is challenged to a race by fellow red engine James. A screeching sound leads Rosie to suggest that James should get his brakes checked, but he is too proud to do that, which leads to trouble.
第 13 集 A Shed for Edward
播出时间：2017年10月5日
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!
第 14 集 The Big Freeze
播出时间：2017年12月2日
When a big freeze hits the island of Sodor, Diesel finally proves himself to be a hero by bringing the coal for the steam engines.
第 15 集 Emily in the Middle
播出时间：2017年12月7日
Emily gets stuck in the middle while helping Donald and Douglas, until she gets derailed at the bottom of Gordon's Hill.
第 16 集 Terence Breaks the Ice
播出时间：2017年12月12日
Terence takes a shortcut across a frozen lake while collecting Christmas trees for the holiday market and Thomas tries to save him.
第 17 集 Daisy's Perfect Christmas
播出时间：2017年12月19日
Daisy is sad when Christmas doesn't go as planned: the Decorating of Vicarstown, the Children, Mike, Rex, and Bert's fake snow show, the electricity problem back at Vicarstown, the Troublesome Trucks singing Christmas Carols, and Harold with the Star. Ryan, Jerome and Judy soon tell her that change is good every year.
第 18 集 Confused Coaches
播出时间：2017年12月23日
Spencer and Gordon accidentally upset their passengers when their competitive behavior gets out of hand and their coaches get mixed up before the New Year's celebration begins.
