Mark finds that a locomotive on his model railway (or railroad if you are American) has been moved mysteriously. Here is the moment where he discvovers the presence of miniature people on his layout.
...The four green coaches, two each side of the gleaming pullman-car,
looked very smart and Mark brought his eyes down to
platform level to admire his train. It was then that he saw it.
Thrown across a bench on the end of the platform was
the tiniest pullover that Mark had ever seen, it was so
small that it wasn't until he picked it up that he was sure
that it was, in fact, a pullover. There was no other child
but Mark in the house, and no girl, who might have had
such tiny clothes for a doll, had ever been up into the
train room. As he gazed at it Mark realised that the gar-
ment was too small even for a doll. It was a wisp of a thing,
but old, torn and grubby as it was—it was still a pullover.
Mark put the pullover on the controller, and sat down
to consider. The old room was quiet, a slight tremor
passed through the house as a heavy vehicle passed out-
side and the house sighed to itself gently. Mark looked to
make sure that the pullover hadn't moved. What with it
and the General's movement, Mark had begun to suspect
that there were others in the house, besides his father and
himself, who were interested in railways. Others inter-
ested enough to move General Purpose !
But Mark had never been a boy to believe in elves and
goblins and such nonsense until that moment. It began to
look to Mark as though he'd been wrong and there might
well be something in that sort of thing after all.
The room had grown so quiet that Mark was sitting
there half-asleep staring at the strange solid driving wheels
of the Barnstaple when a slight movement caught his eye.
He was very careful not to stir, for by this time he
was extremely curious. He wanted to see this strange
character who could move engines, and who left his
clothes scattered around the platform.
Crossing the lines very carefully was a very tiny, little
old man. Wearing a battered, peaked cap and walking
with a stick he came hobbling down the line towards the
Barnstaple. His tiny moleskin trousers were of an ancient
pattern, but looked strangely right for him in the proper,
decent style of the past. His tiny cheeks were red, and he
looked like a countryman out for a walk on some familiar
path.
He stopped by the Barnstaple and poked at the driving
wheels with his stick.
"They be main ugly 'ole wheels that fella Bulleid did
give his engine," he said, just loudly enough for Mark to
hear. Mark kept perfectly still, unwilling to break the
thread.
"Ah, but she's a beautiful steamer," said the old man,
leaning on his stick reminiscently. "Aye—she can go,
Why I 'a seen her a thundering down to Bournemouth on
the Belle. And at Templecombe and Exeter. Aye—and at
Brighton. Happy days—happy days! But he could a given
her some proper wheels instead o' they monstrous old
things. Still—she's a real engine. Smoke and steam and
the smell of oil—they's the proper thing for a h'engine."
What happens next when you meet a miniature person?