“What’s the matter?” asked Leaveland’s voice. “Is this the train?”

“Yes, this is the train, all right,” Allan answered, “but I don’t see anything of the crew.”

“Well, I’ll be hanged!” and Leaveland scratched his head in perplexity. “What do you suppose happened?”

“I don’t know. Let’s take a look at the caboose,” and jumping to the ground, he started back along the train.

The door of the caboose was swinging open, and a glare of yellow light came through it from the oil lamp, with polished tin reflector back of it, which was attached to the front wall. Allan sprang up the steps, with Leaveland after him, and both of them stopped in astonishment at the open door. The caboose was empty, but two stools stood on the floor before the stove, and between them a box on which was a checker-board and checkers. Evidently the conductor and rear brakeman had been playing together, but had been interrupted in their game and had left the board just as it was, expecting to return to it. They had not returned, however, but had vanished as completely as though the earth had opened and swallowed them.

“Well, I’ll be hanged!” said Leaveland again. “There’s something mighty queer about this. If I believed in ghosts, now—”

“No, I don’t think it’s ghosts,” laughed Allan. “But we can’t stop to investigate. We’d better couple the two engines together, and let Number Two push this train back to Schooley’s. You go ahead and have that done, and I’ll stay here. I’ll burn a fusee if I want you to stop, but I don’t think there’s any danger, because nothing will get past Schooley’s till this train has been accounted for.”

“All right, sir,” assented Leaveland, and hurried back toward the engine.

Allan, left to himself, made a careful inspection of the caboose, but search as he might, he could find nothing that shed the slightest light upon the disappearance of the train crew. It was evident that there had been no struggle of any kind. He found the conductor’s report made up ready to turn in at the end of the trip, and his lantern and dinner-pail on the floor near the door. The more he examined the surroundings the plainer it was that when the conductor and brakeman left the caboose, they had expected to return to it in a minute or two. And that they had left it only a short time before was evident from the fact that the fire in their stove had just been renewed and was burning briskly.

He gave up the problem, at last, and getting a fusee out of the box where they were kept, he stepped out upon the rear platform. As he did so, he heard the cars of the train buckling toward him, and an instant later the caboose caught the motion and started slowly up the track toward Schooley’s. The mile was soon covered, and the train, coming to a stop just outside the little town, was run in on a siding, while the flyer proceeded on to the station. There Allan reported it, secured orders for it, and sent it on its way. Then he proceeded to try to solve the mystery of the abandoned freight train.