Mavis the Diesel Engine works at the Ffarquhar Quarry on Thomas' Branch Line. She is a little diesel, but she still works as hard as any other engine. Sometimes, when the Quarry isn't busy, Mavis works at the Sodor Slate Quarry and sometimes, she works with the other engines when the Fat Controller needs help.

The other engines also help Mavis on busy days. Usually, it's Toby when he isn't needed elsewhere. 'Arry and Bert sometimes help too as well as Thomas and Diesel. When the China Clay Works was closed after a rockslide, Bill and Ben worked with Mavis until it could be opened again. The engines like helping Mavis, and the little diesel is always grateful for their help.


One day, Mavis awoke to see a surprising sight. It looked like a lorry was approaching her shed, but it was traveling on the rails.

The Quarry Master climbed down from the lorry's cab. "Good morning, Mavis. I would like you to meet Dunbar the Rail Lorry."

"Hullo," said Mavis politely.

"Same to you," Dunbar answered cheerfully.

"Dunbar has come to help out," the Quarry Master explained. "He will be collecting supplies from the Branch Line and moving tools around the Quarry."

Mavis was puzzled. "But Sir, you know I've done those jobs many times before. I can still manage."

"I know you can, but you can't be in two places at once. While Dunbar handles the small jobs, you will be able to get your trucks arranged quicker." Mavis understood and her Driver soon arrived to start work.


As the days passed, Dunbar could be seen moving the workmen's tools wherever they were needed and when the other engines were busy, he traveled along the Branch Line to collect supplies for the Quarry.

The Quarry Master was right. Mavis was able to get her trucks ready sooner and Dunbar proved himself to be Really Useful. The two of them became good friends and often talked a lot in the sheds, but Mavis couldn't help feeling a little jealous. Dunbar was a hard worker, but his jobs left her with fewer chances to travel around the Quarry and see the Branch Line and she began to feel restless.


Some weeks later, Dunbar was sent to collect some supplies from Tidmouth Harbour. After his Driver's tea break, he was ready to leave when a workman approached them. "There's been a landslide in the Cutting," he said. "You'll have to take a different route."

"No problem," said Dunbar. "Only a slight delay."

It took some time to make the arrangements, but eventually, it was decided that Dunbar would make his way back to the Quarry through Elsbridge Junction and when the Signalman gave his Driver the 'all clear,' they were off.


The journey was taking longer, but Dunbar didn't mind. It was nice to see so many new sights and he tooted happily to the engines as they passed by.

Then there was trouble.

Not long after crossing the River, Dunbar's engine coughed and spluttered. "What's that?" he cried.

"I don't know," said his Driver, "but we better stop."

Luckily, there was a siding ahead. The Driver switched the points and Dunbar clattered into it before stopping. His Driver turned his engine off, but as he opened the bonnet, dark smoke billowed from Dunbar's engine.

"Well, that's torn it," the Driver coughed. "You're not going anywhere for a while." And he went to call for help.


At the Quarry, Mavis had arranged another line of trucks when the Quarry Master arrived. "Dunbar's broken down beyond Elsbridge. That detour must have been too much for his engine. I need you to collect him, Mavis."

The little diesel felt sorry for her new friend and set off immediately. Dunbar was happy to see her. Their Drivers and some workmen pushed Dunbar out of the siding. Mavis was coupled up and they started back quickly.


At last, evening came. Dunbar's engine was fixed, and he was ready to get back to work in the morning. "Thank you for rescuing me, Mavis," he said.

"That's what friends are for. Besides, it was nice to see the Branch Line again after a while." She then told Dunbar about her restless work.

"You know," said Dunbar thoughtfully, "I wouldn't mind swapping jobs with you every now and then. I may not be as strong as you, but I would be happy to help with your shunting, especially if I have nothing to do." Mavis liked Dunbar's idea, and they agreed to ask the Manager in the morning, and so, it was arranged.


Mavis still has her chances to travel outside the Quarry, but she is happy to know that her new friend, Dunbar, is always happy to cover for her on boring days. Other engines still come to the Quarry to help, and Mavis and Dunbar are always happy to help their other friends in return.