“But the fellow doesn’t intimate where the bump is coming. Humph! Perhaps he doesn’t know. I bet that Andy McCarrey, if he has planned to hold up this train again, is not telling many people about it. “Just those who do his wicked work. And who are _they_? Is Whitey Malone down there in Shadow Valley yet? Is it he whom Zeph is watching? Did he set off the dynamite that blew out that pillar? “My goodness! I could ask a hundred questions along this line and get the same answer to all. Nothing! Well——” The train left the outskirts of Rockton without any trouble. It ran smoothly over the well-ballasted track. The engineer and firemen gazed ahead keenly. All were on the alert for trouble, but Ralph did not tell his firemen of the warning he had received. “Why worry them?” he thought. “It’s bad enough that I should feel as though a sword were hanging over me.” CHAPTER XXIII WHAT LIES AHEAD? Whether it was wise or not, Ralph Fairbanks kept this special suspense to himself. In truth, while a fast train like the Midnight Flyer is under headway, the crew on the locomotive have little time for conversation. The atmosphere in the cabin of such an engine as this great eight-wheeler drawing the express was tense enough all the way. There were but four let-ups in this mental strain which was felt by the firemen, as well as by the engineer. The Flyer pulled down to a stop at four stations before reaching the end of the run at Hammerfest. At these stops only, could the men on the locomotive talk with comfort. More keenly than ever on this run did Ralph watch for signals. With raised hands he and the fireman at the other side of the cab signaled to each other the nature of the switch targets and semaphore lights as they picked them up. And now and then, at some dangerous crossing or lonely, empty station, the young engineer caught the secret signal of Mr. Adair’s police—the double flash of an electric torch from the bushes or some other hiding place. The chief detective’s operatives were on hand and faithful to their trust. This fact reminded Ralph the more keenly of Zeph Dallas. What was he doing? Indeed, where was he and what was his situation on this night when so much seemed at stake? Fryburg was the first stop. The Midnight Flyer drew in there without a thing having been observed suggesting the nature of the threat of which Ralph had been warned in the paper he had found under his bench. The night operator at this station ran out and along the side of the train to the locomotive. He reached up a message to Ralph and gave another to the conductor. Under the light near his shoulder Ralph read the following: Fairbanks, engineman, Train 202:— Speed up. Fire reported in timber Shadow Valley near tracks. “Hopkins, Super.”