“I suppose no trains run through the tunnel from Kilty Vale to Olly’s Yard now, then?” he said.

Tucky snorted. “Didn’t I tell ‘ee it’s not bin used for years? The yard at Kilty Vale’s been turned into summat else, though the lines are still there. There’s bin no engine through that tunnel since I were a young man.”

This was all very, very interesting. Julian bought old Tucky a packet of cigarettes which gave him such a pleasant shock that he wanted to tell the children everything all over again. He even gave them the old map.

“Oh, thanks,” said Julian, delighted to have it. He looked at the others. “This’ll be jolly useful!” he said, and they nodded.

They left the pleased old man and went out into the town. They found a little park and sat down on a seat. They were longing to discuss all that Tucky had told them.

“It’s jolly queer,” said Dick. “No trains run there now — the tunnel’s not been used for ages — and Olly’s Yard must have been derelict for years.”

“And yet — there appear to be trains that come and go!” said Julian.

“Then — they must be spook-trains,” said Anne, her eyes wide and puzzled. “Julian — they must be, mustn’t they?”

“Looks like it,” said Julian. “It’s most mysterious. I can’t understand it.”

“Ju,” said Dick, suddenly. “I know what we’ll do! We’ll wait one night again till we see the spook-train come out of the tunnel to the yard. Then one of us can sprint off to the other end of the tunnel — it’s only about a mile long — and wait for it to come out the other side! Then we’ll find out why a train still runs from Kilty Vale to Olly’s Yard through that old tunnel.”

“Jolly good idea,” said Julian, thrilled. “What about to-night? If Jock comes, he can go, too. If he doesn’t, just you and I will go. Not George!”

They all felt excited. Anne wondered if she would be brave enough to go too, but she knew that when the night came she wouldn’t feel half as brave as she did now! No, she wouldn’t go. There was really no need for her to join in this adventure at present. It hadn’t even turned out to be a proper one yet — it was only an unsolved mystery!

George hadn’t come back from her walk when they reached the camp. They waited for her, and at last she appeared with Timmy, looking tired out.

“Sorry I was an ass this morning,” she said at once. “I’ve walked my temper off! Don’t know what came over me.”

“That’s all right,” said Julian amiably. “Forget it.”

They were all very glad that George had recovered her temper, for she was a very prickly person indeed when she was angry. She was rather subdued and said nothing at all about spook-trains or tunnels. So they said nothing either.