Mack had been one of the diesels that had been preserved, but his time in service meant he needed an overhaul. He was excited. The engines of King's Cross had to do his work, as well as their own. It tired them out, but they soon got used to it.

One day, when Max was shunting trucks in the yard, he heard a purring. He assumed it was Norvin or Rattler, until he heard the horn.

"Oh, Mack, back from your over-OH MY GOD!!!!" Mack looked very different. He has a new coat of light brown paint, with horizontal stripes along his side. But there was one difference from his new look: he had a giant claw on his cab.

"Hey Max," said Mack, "What do ya think of Pinchy?" Mack lifted his claw up, and showed it off. "Um, is, that even legal?" asked Max. "The workers said it was, so yeah, it's now a part of me." "Um, why Pinchy?" "It just came to me. Also, I have a new name." "Really?" "It's now Diesel 10." "Why the 10?" "I was the tenth diesel they overhauled." "Why did they give you the claw?" "Mainly for loading trucks with logs, and lifting things off the tracks." "Oh," said Max, "Well, just, be careful." "I will," said Diesel 10.

Diesel 10 put his claw, or Pinchy, to good use. He often helped other engines if their load spilled, or needed help loading. He could often be seen lifting fallen objects off the tracks. Many engines feared him because of this, but they were happy to see Mack had changed a bit. Since preservation, he was a bit kinder, and less hostile towards steam engines.

One day, Diesel 10 was due with a passenger train, since he was the only engine available. When he came back to King's Cross, he saw a GWR 5100 Class 2-6-2T.

"What time do you call this?" asked the engine. "Nice to meet you too," said Diesel 10, "Name's Diesel 10." "What kind of a name is that?" asked the tank engine. Diesel 10 looked at the name plate on his smokebox, and said, "Well, 'Marcus', know that you are preserved, like me. Just know that I'm tired, or else, I would let Pinchy have a go at you." Diesel 10 then crunched his claw, and Marcus just steamed away.

Soon, the other engines knew of Marcus. When Harry came with a passenger train, he saw who he thought was Marcus. "Ah, another Great Western engine?" asked the engine. "Yes, my name is Harry, and you must be Marcus." "I'm not Marcus, I'm Morgan," said the engine. Harry was confused, but soon shook it off, and they talked of the Great Western days.

One day, Diesel 10 was loading some trucks with scrap metal. Just then, the trucks were bashed out of place by Marcus. "Hello!!" he said. Diesel 10 gritted his teeth. Just then, Marcus backed up, and Morgan took his place. "Nice to see you!" he said.

The two engines kept popping up from both sides of Diesel 10, whistling, and saying nonsense, until Diesel 10 said, "STOP!!!! I'M GETTING GITTY!!!!" Once Diesel 10 got his senses back, he looked at the two engines. "THERE'S TWO OF YOU!?!?" "TRICKED YOU!!" said the two engines. Diesel 10 honked his horn, and said that they could've caused an accident if they weren't careful. Just then, another whistle was heard, followed by loud chuffing and puffing, and a large steam engine came in. It was a BR Standard Class 5.

He then said in a booming voice, "Why are these trucks in my way!?!" The engines all quivered in fear, even Diesel 10. The engine then saw their expressions, and said, "Oh, I'm sorry, I didn't mean to scare you." The three engines then looked over at him, and Diesel 10 explained what had happened. The engine then said, "You shouldn't do that. It's dangerous to bump trucks that are being loaded. If you do that, the cargo could fall on a worker, or maybe even a by stander, even if them youngsters should know better than to come here uninvited. Now, how about you two head off to the station, they're in need of two engines to double head a heavy goods." Marcus and Morgan puffed off, and the engine said, "Oh, where are my manners, my name's John." "Nice to meet you John," said Diesel 10, "I must ask, are you a preserved with the Steam of Britain fleet?" "Yes I am," said John. Diesel 10 then frowned, "Oh boy. I fear that many of the engines don't approve of the standard classes." "Why's that?" asked John. Diesel 10 then told him the story of when Geoffrey came. "Oh, I know him very well. We were built in the same workshop, and I had much respect for the older steam engines. I'm sure I can earn their respect." But that's another story.