“Where’s she gone?” said Mr. Luffy, helping himself to a tomato. “Why isn’t she back to dinner?”

“She’s taken hers with her,” said Anne. “I feel a bit worried about her, somehow. I hope she’s all right.”

Mr. Luffy looked alarmed. “I feel a bit worried myself,” he said. “Still, she’s got Timmy with her.”

“We’re going off on a bit of exploring,” said Julian, when they had all finished eating. “What are you going to do, Mr. Luffy?”

“I think I’ll come with you,” said Mr. Luffy, unexpectedly. The children’s heart sank. They couldn’t possibly go exploring for spook-trains in the tunnel if Mr. Luffy was with them.

“Well — I don’t think it will be very interesting for you, sir,” said Julian, rather feebly. However, Mr. Luffy took the hint and realised he wasn’t wanted that afternoon.

“Right,” he said. “In that case I’ll stay here and mess about.”

The children sighed with relief. Anne cleared up, with Jock helping her, and then they called good-bye to Mr. Luffy and set off, taking their tea with them.

Jock was full of excitement. He was so pleased to be with the others, and he kept thinking of sleeping in the camp that night — what fun it would be! Good old Mr. Luffy, taking his side like that. He bounded after the others joyfully as they went off to the old railway yard.

Wooden-Leg Sam was pottering about there as usual. They waved to him, but he didn’t wave back. Instead he shook his fist at them and tried to bawl in his husky voice: “You clear out! Trespassing, that’s what you are. Don’t you come down here or I’ll chase you!”

“Well, we won’t go down then,” said Dick, with a grin. “Poor old man — thinking of chasing us with that wooden leg of his. We won’t give him the chance. We’ll just walk along here, climb down the lines and walk up them to the tunnel.”

Which is what they did, much to the rage of poor Sam. He yelled till his voice gave out, but they took no notice, and walked quickly up the lines. The mouth of the tunnel looked very round and black as they came near.

“Now we’ll jolly well walk right through this tunnel and see where that spook-train is that came out of it the other night,” said Julian. “It didn’t come out the other end, so it must be somewhere in the middle of the tunnel.”

“If it’s a real spook-train, it might completely disappear,” said Anne, not liking the look of the dark tunnel at all. The others laughed.

“It won’t have disappeared,” said Dick. “We shall come across it somewhere, and we’ll examine it thoroughly and try and find out exactly what it is, and why it comes and goes in such a mysterious manner.”

They walked into the black tunnel, and switched on their torches, which made little gleaming paths in front of them. They walked up the middle of one pair of lines, Julian in front keeping a sharp look-out for anything in the shape of a train!