Ahiru is a JR Western tank engine who lives on the Gensokyo Railway. He works hard in the yard at the big station at the Human Village. Sometimes he pulls coaches, sometimes he pulls goods trains, and he shunts in between. Whatever the work, Ahiru finishes his work without fuss.
One day, he was at the sheds when the Scarlet Controller arrived.
"I'm proud of your work on the railway." she said.
"Thank you, sir." replied Ahiru.
"Anyway, the new connection between Kourindou and Mayohiga has been finished and I want you to run it."
"Oh, thank you sir!"
Ahiru soon took charge of his new branchline. The responsibility delighted him. The line connected the market of Kourindou to Mayohiga, the revived village. All the while, cutting through part of the Forest of Magic and past fields of sunflowers. Ahiru loved coasting down the line as the fresh country air swirled his smoke up high as his green paint glistened in the sun.
"This is like being off the grid." said Ahiru.
"Sometimes, a change is as good as a rest." replied his driver.
Soon, Ahiru was busier than ever. There was a new station being built along the line. Various other engines came to help build, construction progressed easily.
"The new station is almost done." said Kiyoshi.
"And on time too." replied Ahiru.
That night, Ahiru was in the shed next to Hachirou. Ahiru felt his responsibility deeply.
"You don't know how much the Scarlet Controller depends on me to run my branchline." he said.
Hachirou rolled his eyes sleepily.
"I'm JR Western and-"
"Quack, quack!" said Hachirou
"What?"
"You heard me? Quack! Quack! You go, you sound like you laid an egg. Now stop talking and let an engine sleep."
"Quack yourself!" said Ahiru, indignantly.
The next morning, Ahiru told his crew about last night.
"Hachirou? Said you laid an egg?" said his driver, "We'll show him."
And the two kappas made a plan. That night, while Hachirou was sleeping, they put something in his tender. They giggled and almost woke him up.
The next morning, as Hachirou's firewoman loaded him up on water. She heard a noise come from the tender.
"Hey! Check this out! There's something in the water!" said the firewoman.
"What do you mean there's something in the water?" asked the driver, climbing onto the tender.
"What's in my tender?" asked Hachirou.
Hachirou soon found his answer, as his crew pulled out a small duckling from out of his tender. The duckling was tame and stayed with the crew. The driver shared her lunch with the duckling and the duckling rode in the cab as they hauled whatever trains needed pulling. The other engines teased him about it. Presently, the duckling grew tired of riding and was let off at Mayohiga station and there she stayed.
That night, Hachirou's crew played a trick back at Ahiru, they got together a box and some straw and the driver and the firewoman got busy. The following morning, when Ahiru's driver and firewoman looked him over. They laughed and laughed.
"Ahiru! Look what's under your bunker! There's a nest with an egg in it!." called out his driver.
Hachirou opened a sleepy eye, "Well, well, well. You must have laid it in the night, Ahiru. All unbeknownst!"
Then Ahiru laughed, "You win Hachirou. It'd take a clever engine to get the better of you."
There was a pond close to the Mayohiga station, where the duckling swam and welcomed the engines as they pass by. The stationmaster calls her Aimi, but to everybody else it will always be known as Hachirou's duck.
