In the summer, the work crews cut the long grass along the tracks—raking it into heaps to dry in the sun.

At this time of year, Percy stops where they have been cutting. The men load up his empty wagons, and he pulls them to the station.

Toby then takes them to the hills for the farmers to feed their stock.

“Wheeeeeeeesh!” Percy gave a ghostly whistle. “Don’t be frightened, Thomas.” He laughed. “It’s only me!”

“Your ugly fizz is enough to frighten anyone,” said Thomas. “You’re like—”

“Ugly indeed! I’m—”

“—a green caterpillar with red stripes,” continued Thomas firmly.

“You crawl like one, too.”

“I don’t!”

“Who’s been late every afternoon this week?”

“It’s the hay.”

“I can’t help that,” said Thomas. “Time’s time, and Sir Topham Hatt relies on me to keep it. I can’t if you crawl in the hay till all hours.”

“ ‘Green caterpillar’ indeed!” fumed Percy as he set off to collect some hay to take to the harbor. “Everyone says I’m handsome—or at least nearly everyone. Anyway, my curves are better than Thomas’ corners. Thomas says I’m always late,” he grumbled. “I’m never late—or at least only a few minutes. What’s that to Thomas? He can always catch up time farther on.”

All the same, he and his Driver decided to start home early. Then came trouble.

A crate of treacle was upset all over Percy.

Percy was cross. He was still sticky when he puffed away.

The wind was blowing fiercely.

“Look at that!” exclaimed the Driver.

The wind caught the piled hay, tossing it up and over the track.

The line climbed here. “Take a run at it, Percy,” his Driver advised.

Percy gathered speed. But the hay made the rails slippery, and his wheels wouldn’t grip. Time after time, he stalled with spinning wheels and had to wait until the line ahead was cleared before he could start again.

Everyone was waiting. Thomas seethed impatiently. “Ten minutes late! I warned him. Passengers’ll complain, and Sir Topham Hatt …”

Then they all saw Percy. They laughed and shouted.

“Sorry I’m late!” Percy panted.

“Look what’s crawled out of the hay!” teased Thomas.

“What’s wrong?” asked Percy.

“Talk about hairy caterpillars!” puffed Thomas. “It’s worth being late to have seen you.”

When Percy got home, his Driver showed him what he looked like in a mirror.

“Bust my buffers! No wonder they all laughed. I’m just like a woolly bear! Please clean me before Toby comes.” But it was no good. Thomas told Toby all about it.

Instead of talking about sensible things like playing ghosts, Thomas and Toby made jokes about “woolly bear” caterpillars and other creatures which crawl about in hay.

They laughed a lot, but Percy thought they were really being very silly indeed.