Thomas has his own branch line, which goes all the way separately from the Junction and Harbor in Knapford to Ffarqhaur. He often goes along down the line with his two coaches, Annie and Clarabel, singing happily together all day.

Sometimes, if Thomas is ill or busy somewhere else on Sodor, Percy or Duck would help run the branch line's passenger services with Daisy and Toby until he comes back. Annie and Clarabel would always miss Thomas a lot, but they are always fond of being looked after by another friendly engine.

One day, Thomas was being called over at Brendam Docks. Diesel was shunting freight cars with Salty when he saw him.

DIESEL: (teasingly) Well, well, well, if it isn't our Number 1 steamie coming to smell the fish.

Thomas was annoyed. He hated the smell the fish, but he didn't bother to mention that to Salty.

SALTY: Arr, take no notice of him, me harty. Just relax and enjoy the view of the sea.

Thomas felt better already.

THOMAS: Thanks a lot, Salty. At least, it's too nice of a day for Diesel to spoil.

Then, Sir Topham Hatt arrived.

STH: Thomas, I have a very special job for you. You are needed to help Edward, Harvey, and Emily repair a couple of tracks on Gordon's Express line. The rails are worn out and will need replacing. It will take a long time.

THOMAS: Yes, Sir. But who will take care of Annie and Clarabel when I'm gone?

SHT: Well, since Percy is busy with the milk today and Duck is helping out on the Little Western with Oliver, I believe that Diesel will have to do your work.

Thomas was absolutely horrified. Diesel, in return, was merely shocked.

THOMAS: Sir, you can't be serious! Leave my coaches with… with… with him?

DIESEL: I never even took passengers before, Sir! I'm only a goods and shunting engine!

SHT: Not to worry, Diesel. Daisy knows a great deal on taking passengers. I've full confidence that she'll teach all you would need to know. Besides, Salty is more than capable in handling the freight cars by himself.

DIESEL: Yes, Sir. Thank you, Sir.

Diesel still didn't feel completely reassured inside. Sir Topham Hatt then turned sternly to Thomas.

SHT: Need I remind you that Really Useful Engines don't argue?

THOMAS: (sighing) Sorry, Sir.

SHT: That's alright, then. Now run along. Emily, Edward, and Harvey can't fix Gordon's track on their own. And Diesel, head over to Knapford Junction. Daisy will be waiting for you there with Annie and Clarabel.

THOMAS & DIESEL: (miserably) Yes, Sir.

Thomas sat off forward, while Diesel reversed to the junction connecting to Thomas' branch line.

When Diesel finally arrived at Knapford Junction, Annie and Clarabel were particularly cross to see him.

ANNIE: Thomas has warned us about you, Diesel.

CLARABEL: So we hope you will be on your best behavior. You probably don't even know how to run this branch line as he does.

Diesel growled loudly.

DIESEL: Listen, you twin piles of…

DAISY: Relax, Diesel. They just need to know you better. That's all. Meanwhile, you're no doubt aware that Sir Topham Hatt has put me in charge on teaching you how to pull passenger trains.

DIESEL: (snorting) If only that was easy enough.

DAISY: Of course it's easy. Any diesel can do it as much as steam engines. All it requires is to pull the coaches smoothly and gently.

DIESEL: Well, you're lucky not to need coaches for that! You just carry passengers on the inside! Maybe Sir Topham Hatt should have sent Bear or BoCo to help me understand better.

Daisy was trying very hard not to get cross.

DAISY: Let's just get you ready for passenger services, shall we? Now switch to the other line and back onto Annie and Clarabel… gently.

After his driver had set the points and back again when on the other track, Diesel did his best as he reversed back to the station.

DIESEL'S DRIVER: Easy does it, boy. You can do it. Just slow down a bit.

Diesel went as slowly as he could and concentrated on where he was backing up. He was just inches away from Annie, when James approached the station and blew his whistle. Diesel jumped and bumped the coaches so hard he nearly derailed them.


CLARABEL: That wasn't very smooth, was it?

DIESEL: (sarcastically) Thank you for the advanced warning, James.

JAMES: Well, if I didn't know better, I could have sworn I saw a bad apple on this branch line. What are you doing here, Diesel?

Diesel and Daisy explained everything.

JAMES: I see. Well, I hope Sir Topham Hatt knows he has made the right decision.

DAISY: Never mind him, Diesel. Let's just continue our lesson.

As the passengers boarded Annie and Clarabel, Daisy motioned Diesel to follow her.

DAISY: Move as smoothly as you can. The passengers won't like a rough ride, now will they? Watch me.

She went ahead moving as if she were a dignified queen. Nervously, Diesel moved as slowly as his driver let would let him.

To his surprise, Annie and Clarabel were running easily from behind. Neither of them seemed to rock or bounce at this pace. Cautiously, he went a little faster and it was as if he already learned how to treat a coach.

DIESEL: Well, what do you know? I think I'm starting to get the hang of this passenger business.

DIESEL'S DRIVER: Steady now, Diesel. You're a strong engine and we must make sure you don't strain the coupling hooks off these coaches, so try to go as fast as Thomas would normally go around here.

Diesel wasn't really sure how fast Thomas goes on the branch line, but this pace was just good enough for Annie and Clarabel. They were amazed.

ANNIE: (to Clarabel) Are you experiencing this?

CLARABEL: Yes. There may be hope for him yet.

Because Thomas' line is separate from Daisy's route, Diesel couldn't keep up with the railcar as she went in a curve. But he needn't have worried. He was doing fine now that he knew how to run a passenger train.

It was when they went through the tunnel that Diesel began to notice something from ahead. He couldn't see it at a long distance, but as he got closer, there was a cow that strayed from the nearest farm and onto the line. His driver applied the brakes.

DIESEL'S DRIVER: Whoa there, Diesel!

As Diesel came to a stop about two meters from the cow, the momentum caused Annie and Clarabel to bump him from behind. Some of the passengers flew from their seats and onto the floor.

Luckily, no one was hurt. At first, the passengers were cross. But they calmed down when they saw the cow outside. Diesel, on the other hand, was more than cross. He was furious.

DIESEL: Grrr… No one told me that this branch line has to deal with these barnyard problems!

ANNIE & CLARABEL: (innocently) Why didn't you ask?

Diesel didn't answer. He just fumed with great frustration.

DIESEL'S DRIVER: Not to worry, Diesel. We'll just have to wait for the farmer to lure the cow away.

DIESEL: (irritated) Whenever Thomas gets back, I'm going to have a long talk with him about this.

Meanwhile, Thomas, Edward, Harvey, and Emily were busy working on the Express line. As Gordon was taking a different route during the repairs, there was little trouble. Harvey removed the old rails with his crane arm and placed them onto some freight cars, which the other three engines would put in a siding until one section of the line was finished.

However, Thomas was more concerned about Annie and Clarabel than the task at hand. Like any engine might do if in a foul mood, he took his anger out on the cars. He constantly bumped the empty ones before they were loaded.

FREIGHT CARS: (separately) Ow! Ouch! Not so rough! Knock it off! What was that for?

THOMAS: Take that, Diesel!

EMILY: (concerned) Um, Thomas… Are you alright?

THOMAS: (angrily) What does it look like, Emily? I'm getting really steamed right now and I don't mean literally. If Diesel gets one dent on Annie and Clarabel – whether intentionally or not – I'll send him personally to the scrap heap!

Emily and Edward looked at Thomas in utter disbelief. This wasn't like the blue tank engine they knew at all.

EDWARD: (firmly) Now, Thomas, I understand you're worried about Annie and Clarabel, but you can't just keep judging Diesel's character, no matter what he's done in the past.

THOMAS: (exhaling with content) I suppose you're right, Edward. But I don't know why Sir Topham Hatt would choose Diesel to be a substitute engine for my branch line.

EDWARD: Well, it's either because he was the only engine available or that he's been given a chance to see how good he would be on passengers. Besides, he helped you and your coaches when you slipped on Daisy's oil. We were all grateful for that, as I recall, and so was Sir Topham Hatt.

EMILY: I've watched how he's been treating Gordon's special coaches when I chased him around the Island. They didn't even get a single scrape or damaged brake-pipe.

Thomas knew that his friends were right and he had to be content with Sir Topham Hatt's orders, however they might sound.

After the cow was moved out of the way and back to the farm, Diesel was determined to make up for lost time. He was worried that Sir Topham Hatt might be cross with him again.

DIESEL'S DRIVER: No need to worry, Diesel. You haven't done anything wrong. Not this time, anyway.

DIESEL: (sarcastic) Well, that's encouraging.

Then, he noticed a familiar shape up ahead on the opposite track in a standstill. He stopped beside his glum diesel railcar mentor.

DIESEL: What on earth are you doing here, Daisy? You should be at Dryaw by now. Don't tell me you've got another oil leak.

DAISY: (sadly) No, it's worse. My exhaust pipe has broken and I'm overheating. Now my passengers are going to be late.

DIESEL'S DRIVER: Well, I suppose we'll need to take more passengers into Annie and Clarabel, but that might mean overloading them…

DIESEL: Wait a minute! I've got an idea.

Diesel told his driver to uncouple Annie and Clarabel. As the driver did so, Diesel went forward, switched tracks, and backed up into Daisy. Then, he raced back to the previous track and gently pushed her in front of Annie, so that she could be coupled from behind.

DIESEL'S DRIVER: Good thinking, Diesel! Now let's get the passengers to Dryaw while we've still got time!

Diesel went as quickly, but smoothly, as possible. Daisy, Annie, and Clarabel didn't know what to think of this, but they felt some comfort that Diesel was there to help them out.

Meanwhile, at Dryaw Station, Percy, Mavis, and Toby were talking about Diesel after finishing their work. They weren't exactly pleased to hear that he was taking Thomas' passengers.

PERCY: (worryingly) Oh, this is bad. This is really bad. What will happen to the branch line's reputation if Diesel messes things up? We're doomed!

TOBY: Calm down, Percy. Daisy's taking care of everything.

PERCY: I know that, but… things were bad enough when Diesel was shunting in our yard. I wonder how worse it'll be, now that he's on passenger duties.

Then, they all heard a familiar sound approaching. It was the sound of a horn from an engine they know very well and were surprised to see him nearing the station, smoothly pulling a green diesel railcar and two old coaches.

MAVIS: (speechless) I… I… I can't believe it!

TOBY: Neither can I, Mavis.

PERCY: Well, I can! This is what I call a nice job well done!

Diesel pulled up on the station platform, letting the passengers out before they thanked him for a splendid run.

DIESEL: (pleased) How about that? This is the first time in a while since I got praise.

DIESEL'S DRIVER: Don't let that get into your head just yet, boy. We've still got some passengers to drop off.

After explaining the situation, most of Daisy's passengers boarded Annie and Clarabel, while Toby, Mavis, and Percy took Daisy to the Stealworks. Then, Diesel went on to finish the rest of the journey.

When the big engines heard the news of Diesel's efforts on Thomas' branch line, they were astounded.

HENRY: Diesel? Succeeding on his first time with passengers? Why, this is dis- dis-

GORDON: Distorting!

JAMES: Disturbing!

HENRY: Disorienting!

Next day, Daisy came back with a brand new exhaust pipe and thanked Diesel for helping her with the passengers while she was away. Together, they made good time and the branch line was put right on track. Mavis, Percy, and Toby were most impressed.

Three days later, the Express line was repaired and Thomas was to return at Knapford Junction. Annie and Clarabel were glad to hear this, but they became used to having Diesel around.

Sir Topham Hatt spoke jollily to Diesel and Daisy.

SHT: Well done, Daisy. I knew I could rely on a passenger expert like you.

DAISY: (flattered) Thank you, Sir.

SHT: And as for you, Diesel…

Diesel squirmed and shut his eyes, waiting for what might be another scolding. Sir Topham Hatt laughed.

SHT: (continuing) I admit that things have a bit rough on your first day of passenger service. But you saved Daisy from an awkward situation and, as days went on, proved to me that you can be as smooth as any Really Useful Engine would have been. I'm very proud of you.

DIESEL: (taken aback) Really? Well… Thank you very much, Sir.

Just then, Thomas pulled up.

THOMAS: I heard about what happened here, Diesel, and I just wanted to say… I'm sorry for misjudging you.

DIESEL: Nah, that's alright, Thomas. I doubted I could do passenger jobs myself, either. But if it hadn't been for Daisy, I'd…

DAISY: (modest) Oh, it was nothing, really. You handled the passengers more than I taught you to all by yourself.

DIESEL: (jokingly) Well… At least, I didn't fall down any mines or came into Stationmasters' houses unannounced. Eh, Thomas?

Everyone laughed.

From then on, Thomas' branch line has been more busier than ever. Diesel is now becoming used to taking passengers as well as freight. Sometimes, he looks after Henrietta, Victoria, and Eslie the luggage van if Toby is away. Sometimes, he delivers the milk to the dairy and his days of smooth passenger runs have paid off.

Even Bertie has warmed to Diesel and told him about the time he raced Thomas. Both agree on a couple of things and one in particular is never to risk a race with Diesel on passenger duties.

Now that shows you, doesn't it?