Diesel 10 is one of the biggest diesels on the Island of Sodor; he is very strong and has a crushing, snapping claw. Whether they run on steam, diesel or electricity, many engines are scared of Diesel 10.

BoCo is also a big diesel and he's very strong too. He likes to get the job done without fuss, but he is very friendly and treats every engine with the same respect.

One day, Diesel 10 was in Vicarstown Yard collecting scrap for the Smelter's Yard. He was ready to leave, but BoCo was on the same line. "Out of my way, you big, green cucumber!" he snarled.

"I can't leave until the line's clear, Diesel 10," replied BoCo firmly. "You'll have to be patient."

Diesel 10 growled; he didn't want to wait. Then, he had an idea. He backed up to another set of points and after checking that his path was clear, he raced across the points to the other line. Suddenly, he saw James coming the other way.

"What?!" James cried and braked hard…He just missed Diesel 10 as he passed onto another line. James and BoCo was shocked.

Diesel 10 carried on with his work, but everywhere went, he kept passing BoCo. Sometimes, he even had to stop and wait for him again. All the steam engines blew their whistles, the diesels honked their horns and BoCo always honked back.

When Diesel 10 got back to the Dieselworks, he wouldn't stop grumbling to himself. "Who does that big, green diesel think he is?! 'Hello, BoCo.' 'Lovely day, BoCo.' 'We all like BoCo!' Augh! I can't stand that engine!" Diesel 10's motors growled loudly. "It's high time I showed that good-for-nothing diesel what it really means to be as big and strong as I am!"

The next day, Diesel 10 was taking some trucks to Knapford Yard when he came to the rail crossing and there was BoCo, waiting with his train for Mavis and Percy to pass. Diesel 10 wouldn't stand for it. "Get a move on, you!" he shouted.

BoCo was getting fedup. "Will you please calm down already? We must wait our turn. What you did yesterday was very dangerous and you should know better."

Diesel 10 clashed his claw; he was very cross. He didn't like BoCo telling him what to do, or being so friendly to everyone, but making him wait was worst of all. "Who do you think you are telling me what to do!?" he growled. "I have had it with you, you big, green, roaring heap of junk!"

Then, everything happened at once.

Diesel 10 surged forward and bashed BoCo's trucks. Mavis and Percy applied their brakes…but it was too late. BoCo and Mavis crashed into each other and stone and metal parts were scattered everywhere.

Luckily, no one was hurt.

"Ouch!" groaned BoCo and looked back, "Diesel 10, what was that for?!"

"Serves you right!" Diesel 10 called back, and he raced away; he didn't want to be blamed for the accident.

Harvey soon arrived with the Breakdown Train to clear the mess. The Fat Controller was most annoyed. "What happened here?"

"Diesel 10 pushed me into Mavis' path, Sir," BoCo explained. "I told him to wait, but he wouldn't listen. That engine has been causing trouble all day." The Fat Controller frowned and listened carefully.

That evening, Diesel 10 was resting in his Shed. Then…the Fat Controller arrived…with the Smelter's Yard Manager…and they were very cross.

"Diesel 10!" snapped the Manager, "I cannot believe what I've been hearing. Sir Topham Hatt tells me that you nearly caused an accident in Vicarstown today and pushed BoCo into Mavis at the rail crossing. Is this true?"

Diesel 10 didn't want to hear about BoCo anymore. "I can't stand that BoCo!" he shouted. "I could've cleared the line before James arrived if he wasn't blocking my way and I would've cleared the crossing before Mavis even reached it. Who does BoCo think he is anyway?! Call himself a diesel?! He gives us diesels a bad reputation?! He's a disgrace to us all!"

"No, Diesel 10!" snapped the Fat Controller, "it's engines like you who give diesels a bad reputation! Sometimes, I wonder why we bother with you! You have caused confusion and delay continuously ever since you first arrived and have given me a lot of trouble! You, Diesel 10, are a very disobedient engine! You will stay in your Shed until we have decided what to do with you!" And with that, the Fat Controller and the Manager left.

The other diesels could hardly believe what they had heard. They had never heard the Fat Controller or the Smelter's Yard Mananger speak to anyone like that…except Diesel 10.

That night, Diesel 10 sat alone in his Shed. For the first time in years, he was actually worried about what was going to become of himself…but that's another story.