The big eight-wheeler was being rolled out of the roundhouse as Ralph turned back toward the brick station. He saw By Marks, his face washed of blood, and now in a clean overall suit, sitting on the bench in the driver’s side of the cabin, as the huge locomotive wheeled across the turntable.

“Good luck to you, old man!” cried Ralph, and waved his hand to the grave-faced engineer.

Afterward Ralph was glad he had given Byron this hail. The long train of varnished cars had been standing under the train shed for half an hour. The train on the other road rolled in at the far end of the station and the passengers piled out and joined those already occupying their staterooms or berths in the coaches of the Midnight Flyer.

Suddenly Ralph was halted. A hand had fallen heavily on his shoulder and he turned swiftly to look at the person who had touched him. It was the tall man in the long black coat who had been sitting in the office of the supervisor. Ralph cried out with satisfaction.

“Mr. Adair! I certainly am glad to see you!”

“I was looking for you, Ralph. But I supposed you were at home at this hour and I hated to disturb your mother,” said the chief detective of the Great Northern system.

“Oh, no. I am around the offices now, every night. Until this Midnight Flyer pulls out, at least.”

“I don’t suppose the supervisor knows that, does he?” asked Adair dryly.

“He knows it to-night, anyway,” said Ralph, grimly. “I was just asking him for you—or if he knew where you were.”

“Indeed? And he said he didn’t know?”