They walked into the station. They went up to a railway plan and studied it. It didn’t tell them much. Julian turned to a young porter who was wheeling some luggage along.

“I say! Could you help us? We’re camping up on the moorlands, and we’re quite near a deserted railway yard with lines that run into an old tunnel. Why isn’t the yard used any more?”

“Don’t know,” said the boy. “Ee should ask old Tucky there — see him? He knows all the tunnels under the moors like he knows the back of his hand. Worked in them all when he was a boy.”

“Thanks,” said Dick, pleased. They went over to where an old whiskered porter was sitting in the sun, enjoying a rest till the next train came in.

“Excuse me,” said Julian, politely. “I’ve been told that you know all about the moorland tunnels like the back of your hand. They must be very, very interesting.”

“Me feyther and me grandfeyther built they tunnels,” said the old porter, looking up at the children out of small, faded eyes that watered in the strong sunlight. “And I’ve bin guard on all the trains that ran through they.”

He mumbled a long string of names, going through all the list of tunnels in his mind. The children waited patiently till he had finished.

“There’s a tunnel near where we’re camping on the moorlands,” said Julian, getting a word in at last. “We’re not far from Olly’s farm. We came across an old deserted railway yard, with lines that led into a tunnel. Do you know it?”

“Oh ay, that’s an old tunnel,” said Tucky, nodding his grey head, on which his porter’s cap sat all crooked. “Hasn’t been used for many a long year. Nor the yard either. Weren’t enough traffic there, fur as I remember. Shut up the yard they did. Tunnel baint used no more.”

The boys exchanged glances. So it wasn’t used any more! Well, they knew better.

“The tunnel joins another, doesn’t it?” said Julian. The porter, pleased at their interest in the old tunnels he knew so well, got up and went into an office behind. He came out with a dirty, much-used map, which he spread out on his knee. His black finger-nail pointed to a mark on the map.

“That’s the yard, see? It was called Olly’s Yard, after the farm. Them’s the lines to the tunnel. Here’s the tunnel. It runs right through to Kilty Vale — there ’tis. And here’s where it used to join the tunnel to Roker’s Vale. But that were bricked up years ago. Summat happened there — the roof fell in, I think it was — and the company decided not to use the tunnel to Roker’s Vale at all.”

The children listened with the utmost interest. Julian reasoned things out in his mind. If that spook-train came from anywhere then it must come from Kilty Vale, because that was the only place the lines went to now, since the way to Roker’s Vale had been bricked up where the tunnels joined.