There was not a signal light along the old, abandoned reach of tracks, and only one or two scattered settlements to pass. At length they came in sight of the signals of the north branch. No. 93 paralleled it on a curving slant for nearly a mile. They were barely two hundred rods from the point where they would slide out onto the rails of the branch, and Ralph had started to let down on speed, when his helper uttered a vivid shout. "Fairbanks--something coming!" Ralph cast his eyes to the other side of the cab. Something, indeed, was coming--coming like a flash, going like a flash. It whizzed even with them, and ahead, like some phantom of the rail. Its course was so swift that the cab lights were a flare, then a disappearing speck. "We are too late," said Ralph. "That is the runaway." "So?" questioned Roberts, who only half understood the situation. "We ran here in the hopes of ditching that engine." "Did?" "We're too late." "Are?" "Roberts," added the young railroader determinedly, "we've got to catch that runaway." "Then it's a race, is it?" asked Roberts, grasping the fire rake. "Yes." "I'm with you to the finish," announced the doughty fireman of No. 93. CHAPTER XV CHASING A RUNAWAY "What's the programme?" asked Roberts, after filling the fire box with coal. "We must beat the speed of that runaway locomotive," replied Ralph. The wild engine was going at a terrific rate of progress. Ralph could only surmise where she had been started on her mad career. The motive, her intended destination, how long she would last out--all this he could only guess at. A drift of cinders struck his face as he shot No. 93 across a switch and out upon the in track of the north branch. At the same time he bent his ear and listened critically to the chug-chug of the escape valves. "Some one is aboard of that engine," he told Roberts. "Then it's a chase instead of a race," said the fireman. "All right. You boss and watch out ahead." Pursued and pursuer were now on parallel tracks. Ralph wondered if he could be mistaken, and the locomotive ahead a special or returning from duty. To test this he gave a familiar challenge call. From ignorance or defiance there was no response. Ralph was sure that the locomotive was in charge of some one. Its movements, the cinder drift, the wheeze of the safety valve, told that the machinery was being manipulated. Ralph cast up in his mind all the facts and probabilities of the hairbreadth exploit in which he was participating. He acted on the belief that the locomotive he was chasing was wild, or soon to be put in action as one. It would be run to some intended point, abandoned, and sent full speed ahead on its errand of destruction. Ralph did not know what might be ahead on either track. The schedule, he remembered, showed no moving rolling stock this side of the north main. He urged his fireman to fire up to the limit and did some rapid calculating as to the chances for the next twenty miles.