Thomas the Tank Engine works at the Big Station, fetching coaches for the bigger engines. He keeps teasing Gordon the Big Engine, making him very cross. When the Shunter later accidentally forgets to uncouple Thomas from Gordon's coaches, Gordon decides to be really fast to tire Thomas out.

Edward is feeling sad, as all the other engines are bigger and younger than him. But when Gordon gets stuck whilst pulling trucks up a hill, it's Edward to the rescue.

Henry the Green Engine doesn't like getting his paint wet - so refuses to come out of the tunnel. The Fat Controller tries everything, including getting Thomas to push Henry out but the big green engine still does not move. In the end, the Fat Controller orders a brick wall be built to block the tunnel entrance, meaning Henry stays in the tunnel forever...

Henry is sad that he is stuck in the tunnel, and Gordon is having fun teasing him whenever he passes. One day Gordon's safety valve bursts just outside the tunnel. Edward is the only other engine available, but the train is too heavy for him. How could the situation possibly be resolved?

Thomas wants to pull a train instead of just shunting coaches for the big engines, who laugh and say he wouldn't be able to do it. One night Henry is ill, and next morning he still isn't better. He is due to pull the morning train, and when no other engine is available, Thomas has to pull the train. He is so excited, he doesn't notice until too late that he has started before being coupled to the train, leaving his coaches and passengers left stranded at the platform!

Thomas is bored, and when one night Edward offers to swap duties with him for the next day, Thomas takes up the offer. This involves taking Edward's trucks. However Thomas is not used to trucks...

Thomas is in the yard shunting when new engine James rushes past with a goods train yelling for help. James has wooden brakes and the trucks are pushing him down the line. The alarm goes - James has crashed into a field of cows. Thomas has to get the Breakdown Train and help James. Afterwards, the Fat Controller gives Thomas a very special reward.

James the new engine has to pull some coaches with the help of Edward. They do very well but James is so excited that he accidentally showers water all over the Fat Controller's new top hat! Later on he is pulling more coaches and bumps them so hard that a brake pipe is damaged. Newspaper and a leather bootlace could temporarily mend the problem, but only a passenger willing enough to hand over their laces will the train be able to continue...

James is feeling sad as he is still staying in his shed for being naughty. Eventually the Fat Controller lets him out to pull a goods train, but the trucks don't want to be pulled by James and misbehave. Whilst pulling them up Gordon's Hill, a coupling breaks and the last few trucks roll back down the hill. James goes to get them (they were stopped by the Guard) and starts on up the hill once more...

Gordon boasts to James that he is the only engine who can pull the Express. One day he sets off with it, but due to points problems he comes back to the station feeling very sheepish. Another engine will now have to take over the job of pulling the Express for the day, but who will it be?

One day Thomas is late with his train due to Henry being late at the Junction, and when the Guard blows his whistle Thomas zooms off - without giving the Guard enough time to get on the train! Annie & Clarabel try to stop him, but Thomas continues to steam on!

Thomas has a desire to fish, and the others tell him "Engines don't fish!" When the water tower is out of order, Thomas has to take water from the river via a bucket. When suddenly he feels like he's going to burst, the Driver and Fireman look inside his tank and discover something rather unusual...

In Autumn, Thomas stops by a signal. There he meets Terence the Tractor, and teases him about his caterpillar tracks. When winter comes, so does the snow. Thomas refuses to wear his snowplough, and when he does he breaks it. Due to this he ends up getting stuck in the snow...

Bertie the Bus challenges Thomas to a race, to see who can get to the end of the line first. Thomas faces obstacles such as stations, signals and a slow start, Bertie has bus stops and traffic lights - who will win?

Gordon has to pull his train backwards due not trying hard enough to move into the correct position on the turntable, so as to be turned around. And when James gets on the turntable, the strong sea winds spin it round much too fast. The two, plus Henry, are very cross about the the unfortunate events that happened to them and so all formulate on a plan...

Henry, Gordon and James decide to go on strike, declaring that "Tender Engines don't shunt!" The Fat Controller sends Edward to do the work; but when poor Edward is being teased, the Fat Controller then decides to buy a new tank engine called Percy.

After being shut up for days in the shed, Henry, Gordon and James have been let out to work again. So the Fat Controller sends Thomas, Edward and Percy to play on the Branch Line. But Percy, however, becomes a little too cocky for his own good and suddenly finds himself on the Main Line - and on a collision course with Gordon...

Henry keeps feeling ill, unlike the other engines. It turns out that Henry's firebox is much smaller than the other engines', so the Fat Controller orders special Welsh coal that will allow Henry to work better. The Green Engine is thrilled with the results.

One winter's evening, Henry is excited to be given the chance to pull the fish train that the men call, "The Flying Kipper". Unfortunately, snow and ice result in an accident. The Fat Controller decides to send Henry off to the Works at Crewe, where Henry will unknowingly be given more than just a repair job...

Gordon becomes a little too above himself but learns a lesson when his whistle valve comes out of place causing quite a noise!

Meanwhile, some boys also soon learn a lesson after throwing stones at Henry and his coaches from an overhead bridge.

We meet Toby the Tram Engine and his coach Henrietta, who both work hard on their little line. One day, a stout gentleman (the Fat Controller), his wife and grandchildren, Stephen and Bridget, come to visit and become very fond of Toby. Some months later, the line is sadly closed, but little does Toby know he has been saved by a letter from a certain personage...

There is a Quarry at the end of Thomas's Branch Line, and he has to take the trucks to and from it. One day a new Policeman starts work and tells Thomas off because he has no cowcatchers and sideplates. It turns out this is the Law, so the Fat Controller will have to build them for Thomas. Thomas says he will look like a tram. But rather than give Thomas a tram overhaul, a much better idea has come into the Fat Controller's mind...

Toby and Henrietta are old and shabby looking. James remarks about how dirty they are, and says how he'd never be seen looking like that. James then has to pull a goods train along Gordon's Hill, but the trucks push him down and up ahead, a train of Tar Wagons lies...

It's Christmas on the Island of Sodor, and after Edward reminds the engines of last Christmas when an ill Mrs Kyndley waved her dressing gown out of her window to save Thomas from a landslide, Thomas decides to thank Mrs Kyndley properly by having a Christmas party for her. The Fat Controller agrees. However, on the day of the party, Mrs Kyndley is trapped in her house by snowdrifts, so Thomas, Toby and Terence go to her rescue.

One day, Gordon is dozing in a siding when Henry comes by, waking him up with a loud whistle or two! Gordon tells Henry, "Mind you keep on the rails today," in regard to his previous incident with the Flying Kipper. Not long afterwards, Gordon feels most annoyed when he is asked to pull a goods train. So whilst on the turntable, he tries a bit of sabotage - which doesn't go according to plan...

Gordon is in disgrace after falling in the ditch. Thomas teases him about it, saying he has, "A funny, musty, sort of smell!"Later, Thomas has to deliver trucks to an old Lead Mine. The ground beneath the rails running overhead is weak and whilst it can support the weight of trucks, it can't support the weight of an engine. But Thomas ingnores the "Danger" signs.

Thomas boasts of how his blue paintwork looks splendid. But he doesn't look so splendid when he gets covered in coal dust whilst working at the Coal Hopper! Percy laughs at his friend's accident, but it's not long before he has a mishap with coal too!

Old Edward unknowingly loses part of his train due some bothersome cows who break out of their field and cause a coupling to come loose. He feels very cross when Henry and Gordon laugh about it and boast that cows wouldn't bother them. However, they'd reckoned without Bluebell the cow!

It's not a good day. Thomas's fireman doesn't come into work, which means that Thomas can't deliver his passengers, which means that he can't make his connection with Edward, which means that this makes everyone late and cross. Bertie offers to take Thomas's passengers; but he has a field day of it when Edward, tired of waiting, steams away. The chase is on!

In a lonely, rusty Scrapyard is poor Trevor the Traction Engine, who is ready to be broken up. He is feeling sorry for himself because he feels that he's too old-fashioned to be Useful. Edward finds Trevor's situation to be a tremendous shame, and is determined to find someone to buy Trevor and save him, but who would "have room for a Traction Engine at home?"

Some boys fiddle with James's controls and he trundles off down the line by himself. It is up to Edward to catch up with James and allow James's fireman to jump aboard the runaway engine to stop him.

Trevor is getting bored, but Edward has good news. The Fat Controller wants Trevor to help with his new Harbour. Edward takes Trevor to the Junction, where the Traction Engine meets Thomas. Thomas takes him down to the Harbour, but has his doubts as to how useful Trevor can be since he doesn't run on rails. Thomas is soon pleasantly surprised.

Percy has been playing tricks on the bigger engines, such as telling Gordon he is late for his train and telling James he mustn't leave the shed because an Inspector is coming to visit. Gordon and James want their revenge, and so come up with a plan to trick Percy, by brainwashing him with the ludicrous idea of "backing signals"...

Percy is ill of the bigger engines around ordering him about. The Fat Controller releases him to work at his new Harbour, and also brings in a new engine called Montague, but who prefers the name of "Duck". The big engines try and order Duck around as well, but Duck won't stand for it and together with Percy, he puts them in their place.

Percy is enjoying his new work at the Harbour. The line is near an airfield, where a boastful helicopter called Harold lives. He reckons that, "Railways are slow and quite out of date!" But Percy proves a point when he challenges Harold to a race...

Thomas is feeling unwell, so Edward takes him to the Works to be repaired. Whilst Thomas is away, Duck fills in for him and is very popular with Annie, Clarabel and the passengers. When Thomas comes back, he resumes his duties. However his handbrake hasn't been fixed properly by the workmen and one day the Fireman forgets to pull it hard enough. As a result, Thomas and the coaches "run away", and only Harold and an Inspector can help stop the runaway train.

Percy brags that "Water is nothing to an engine with determination!" But he feels very foolish when he learns that you can't trust trucks and takes an unfortunate dip!

Duck is boasting about being Great Western and how useful he is, much to the annoyance of the others. Later, the Fat Controller introduces Diesel, a shunter who is "on trial". He asks Duck to show Diesel around, but Diesel says he doesn't need Duck. Duck leaves him to it and Diesel has an accident with some trucks. He thinks it's Duck's fault...

Diesel is still angry at Duck, and plans his revenge. He tells the trucks jokes about Gordon, James and Henry, and says Duck told them to him. The trucks start gossiping, and soon enough the big engines find out...

Duck has been sent to work with Edward for a while, and tells Edward that the Fat Controller and the other engines all hate him. Edward says they don't, and asks Duck if he would like to help him work. Duck helps Edward pull a heavy goods train up Gordon's Hill, but the trucks break away and speed down the line. Duck manages to control them but a barber's shop is up ahead...

The viaduct is being repaired on the Main Line. The Fat Controller doesn't want to close the railway whilst the repairs are being done, and so orders the mainliners to go slowly when crossing it. This delays them with their journey to Thomas, which makes him late to meet with Bertie. Altogether, Thomas becomes very annoyed; until the day comes when he realises that being late isn't such a bad thing after all.

Donald & Douglas have arrived from Scotland to help the Fat Controller - but have caused great confusion in that only one engine was expected! Despite all, they try their best but a spiteful brake van causes trouble between them.

The engines are worried that Donald & Douglas might be sent away after their accidents. Edward suggests that they hold a Deputation - and poor Percy gets the task to tell the Fat Controller about it!

For many years, Thomas the Tank Engine has run his well-known branch line, and knows just where to stop. "You could almost manage it without me!" jokes his Driver. What a surprise Thomas gets when he tries to do so and pays the Stationmaster an unexpected visit!

Thomas's recent accident has caused a great deal of trouble. The Fat Controller decides to send for a Diesel Railcar called Daisy to help Percy and Toby "while Thomas is... ummm... indisposed!" But poor Percy and Toby have a hard time when Daisy becomes difficult and bitter.

Percy grumbles about taking the milk when Daisy doesn't bother to do so. Toby offers him to swap jobs; he takes the milk and Percy fetches his trucks. However, Percy becomes rather cocky and soon finds himself in trouble with runaway trucks and a breakvan in the way...

Bill & Ben are twins who work at the China Clay Pits. One day, they are aghast when they discover that their trucks have gone missing! Down the line, they cause great problems and difficulty with a diesel called Boco, who they believe stole the trucks. Confusion regains until Edward explains everything.

Since the arrival of Boco, Gordon is upset when the Fat Controller allows branch line diesels to pull main line trains. Edward suggests that he should run on the branch for a change. Gordon thinks such an idea "vulgar", but little does he know that a run on the branch is quite unexpectedly in store that night...

Henry, Gordon and James are teasing poor Edward about being too old and "how he should be preserved before it's too late." Duck and Boco tell them to "Shut up!" as "Edward's better than any of you!"; and during a serious breakdown on an important journey, Edward proves his worth once and for all.

Percy tells Thomas and Toby a story about a ghost train. Thomas doesn't believe it and says Percy is a "silly little engine". Percy's Driver later tells him it wasn't true, it was on television. Later that night, Percy is on his way back from the Harbour when he crashes into a lime cart trapped on a crossing. Now white as a sheet, and with help from Toby, Percy heads off to find and scare Thomas...

During the summer, Percy likes to help the harvesters by delivering their bales of hay to Toby, who takes them to the farms, to feed the animals. Unfortunately, Percy makes Thomas very late and cross indeed. Percy doesn't care until a crate of treacle and a hay storm cause some embarrassment...

The Fat Controller sends Thomas to fetch the Christmas Tree for the Christmas party, but on the way back he gets stuck under a big snowdrift. No-one knows what has happened to Thomas, so Donald & Douglas go out to look for him. Will Thomas get home in time?