Thomas and friends script but Diesel only speaks in anagrammed versions of his speech:

Ringo Starr: Duck is very proud of being Great Western. He talks endlessly about it. But he works hard too, and makes everything go like clockwork. It was a splendid day. The trucks and coaches behaved well. The passengers even stopped grumbling. But the engines didn't like having to bustle about.
Duck: There are two ways of doing things.
Ringo Starr: Duck told them.
Duck: The Great Western Way, or the wrong way. I'm Great Western and--
Henry, Gordon and James: Don't we know it!
Ringo Starr: They groaned. The engines were glad when a visitor came. He purred smoothly towards them. The Fat Controller introduced him.
The Fat Controller: Here is Diesel. I have agreed to give him a trial. He needs to learn. Please teach him, Duck.
Diesel: Good morning.
Ringo Starr: Purred Diesel in an oily voice.
Diesel: Pleased to meet you, Duck. Is that James and Henry and Gordon too? I am delighted to meet such famous engines.
Ringo Starr: The silly engines were flattered.
Engines: He has very good manners.
Ringo Starr: They murmured.
Engines: We are pleased to have him in our yard.
Ringo Starr: Duck had his doubts.
Duck: Come on!
Ringo Starr: He said. Diesel purred after him.
Diesel: Your worthy Fat--
Duck: Sir Topham Hatt, to you.
Ringo Starr: Ordered Duck. Diesel looked hurt.
Diesel: Your worthy Sir Topham Hatt thinks I need to learn. He is mistaken. We diesels don't need to learn. We know everything. We come to a yard and improve it. We are revolutionary.
Duck: Oh!
Ringo Starr: Said Duck.
Duck: If you're revo-thing-a-gummy, perhaps you would collect my trucks while I fetch Gordon's coaches.
Ringo Starr: Diesel, delighted to show off, purred away. When Duck returned, Diesel was trying to take some trucks from a siding. They were old and empty. They'd not been touched for a long time. Diesel found them hard to move.
Diesel: Pull! Push! Backwards! Forwards!
Trucks: Ohieee! Ohhh!
Ringo Starr: The trucks groaned.
Trucks: We can't! We won't!
Ringo Starr: Duck watched with interest. Diesel lost patience.
(Diesel growls)
Ringo Starr: He roared, and gave a great heave. The trucks jerked forward.
Trucks: Oh! Oh!
Ringo Starr: They screamed.
Trucks: We can't! We won't!
Ringo Starr: Some of their brakes snapped and the gear jammed in the sleepers.
(Diesel growls)
Duck: Ho, ho, ho!
Ringo Starr: Chuckled Duck. Diesel recovered and tried to push the trucks back, but they wouldn't move. Duck ran quietly around to collect the other trucks.
Duck: Thank you for arranging these, Diesel. I must go now.
Diesel: Don't you want this lot?
Duck: No, thank you.
Ringo Starr: Diesel gulped.
Diesel: And I've taken all this trouble. Why didn't you tell me?
Duck: You never asked me. Besides...
Ringo Starr: Said Duck.
Duck: You were having such fun being rev-whatever it was you said. Goodbye.
(Diesel growls)
Ringo Starr: Diesel had to help the workmen clear the mess. He hated it. All the trucks were laughing and singing at him.
Trucks: ♪ Trucks are waiting in the yard, tackling them with ease'll, ♪ ♪ "Show the world what I can do," gaily boasts the Diesel. ♪ ♪ In and out he creeps about, like a big black weasel. ♪ ♪ When he pulls the wrong trucks out, "Pop!" goes the Diesel. ♪
(Diesel growls again)
Ringo Starr: Growled Diesel, and scuttled away to sulk in the shed.