It was a bright morning at the Depot when the Thin Controller came to see the engines. "There is to be a special exhibition at the Earl's Railway Museum soon," he said. "It will celebrate all the railways on Sodor. Skarloey and Rheneas, as you two were the first engines on this railway, you will be attending the exhibition together." The two old engines were very excited. "And in preparation for this exhibition," the Thin Controller continued, "I have arranged a special surprise for both of you. Bring them out, Rusty!"

The little diesel rolled out of the Sheds…and coupled behind him were four coaches and a guard's van all shining with lovely new paint. Skarloey and Rheneas beamed with pride; they knew who they were looking at.

"Agnes, Ruth, Jemima, Lucy, Beatrice!" exclaimed Skarloey, "we haven't seen you out and about in years!"

"Who are they?" asked Freddie.

"When our railway was first built," replied Rheneas, "these were our first coaches."

"By the time Sir Handel and Peter Sam came here, they became very worn out," Skarloey added. "Not long after Duke arrived, they were set aside for repairs, but we had so many other coaches by then that their repairs weren't urgent."

"Well, the line couldn't do without us forever," said Agnes, proudly, "especially a fine coach like me." Skarloey and Rheneas sniggered; they had heard Agnes' boasting before.

Soon, the Thin Controller explained that the Sheds needed repairs. Until they were ready, the engines would use their old Sheds at Crovan's Gate, but they didn't mind. The old Sheds brought back lots of memories to them, especially Skarloey and Rheneas.

A week later, Sir Handel came home feeling exhausted; he had had a long day. The old coaches, Agnes, Ruth, Jemima, Lucy and Beatrice had been awkward.

"Those old dears need kindness," said Skarloey.

"Exactly," agreed Rheneas, "you be thankful, Sir Handel, that we're not a mountain railway."

Sir Handel was confused. "A mountain railway? What's that?"

"A railway which climbs mountains, of course."

"But it can't; its engines' wheels would slip."

"But it can," said Rheneas. "We've heard of one quite near here, and do you remember Thomas' friend, Ashima, from India? She's a mountain engine too because part of her line is so steep."

Then, the engines watched as Donald shunted a flat truck to a siding nearby…and on it was a queer-looking engine. He had six small wheels and a stovepipe chimney. His boiler was tilted downwards, and his cylinders were back-to-front.

"Wheesht," whispered Donald hoarsely, "dinna wake the wee engine; it's tired, he is. He's away back from the Mainland after being mended. You know how it is."

"We understand," said Rheneas, "but who is he?"

"He's called Culdee, after the mountain his railway climbs."

"Well, did you ever!"

Donald puffed away and Culdee woke to find the engines gazing at him. "Oh, excuse me, but…where am I?"

"This is Crovan's Gate on the Island of Sodor," explained Skarloey.

"That's good," said Culdee, "I'm nearly home now."

"Pleased to meet you, Culdee. I'm Skarloey and this is Rheneas and Sir Handel. We work on the Narrow-Gauge Railway. Actually, part of our line runs close to the mountain of Culdee Fell."

Culdee smiled. "Oh yes, I've heard of you."

"Do you really climb that mountain?" asked Skarloey.

"Yes, I've done it for years."

"You must be clever. We couldn't; our wheels would slip."

"I'm not really clever," laughed Culdee. "I was just built with pinion wheels on my driving axles. They have teeth, you see, which fit into a rack rail. So, I can't slip, however steep the line is."

"That must help you going up," said Rheneas, "but if your line is so steep, aren't you frightened coming down? Coaches and trucks are sometimes silly and try to push engines downhill. Some engines find it hard to stop them."

"Well," said Culdee thoughtfully, "we have good brakes, and our coaches and trucks are never silly like that; they know such tricks are dangerous. I've never had an accident, myself…but I was frightened once; very frightened, indeed.

"Please, tell us," said all the engines, so Culdee began.

One day, long ago, before the Mountain Railway was opened, the Drivers made all five of the engines stand ready outside their Shed. "The Inspector's coming," they said. "We don't know which of you he'll choose."

When the Inspector arrived, he chose Culdee. He climbed into Culdee's cab and made him push two empty coaches to the summit.

Culdee climbed higher and higher up the Mountain; everything seemed to be going well. Then, they reached the steepest part of the line. Down the tracks went behind them with a nasty curve below edging a precipice.

"So far, so good," said the Inspector. "Now, we'll test your brakes." The climbed higher and higher still…"Brakes off, Driver, let him roll."

Culdee couldn't believe what he had heard. The coaches nudged him, and they gathered speed downhill; he was terrified.

His Driver was scared too and reached for the brake. "Hand's off!" ordered the Inspector.

Then, Culdee remembered; he had automatic brakes and could put them on himself. Perhaps the Inspector wanted to see if he could…They worked beautifully and slowed the runaway train to a gentle stop.

"Well done, Culdee," said the Inspector, "you'll do."

"I smiled, of course," Culdee finished, "but I felt very shaky. My Driver and Fireman had been nervous too and mopped their faces, but I'm never nervous now. Why should I be? There's no need." The Narrow-Gauge Engines all stared in amazement.