He gazed anxiously over his shoulder, in the direction in which he was flying, and was relieved to discover that the rails were clear. Then he took a careful look at the line of cars bounding after him. There was no doubt that the train was nearer. The leading car was within two hundred yards of him, and a minute's inspection told him clearly that the distance between them was lessening very rapidly; for the runaway now seemed to have taken the bit between her teeth with a vengeance. Despite the weight of earth and rock in the cars they were swaying and leaping horribly, causing their springs to oscillate as they had, perhaps, never done before. The wheels on the leading bogie seemed to be as much off the iron tracks as on them, and at every little curve the expanse of daylight on the inner side beneath the trucks increased in proportions, showing how centrifugal force was pulling the heavy mass and endeavouring to upset it. It was an uncanny sight, but yet, for all that, a fascinating one. Jim watched it helplessly, almost spellbound, conscious that the few moments now before him were critical ones. He unconsciously set to work to calculate how long it would take, at the present rate of comparative progression of his own car and the runaway train, for the inevitable collision to occur. Then, seeing the heaving bogies of the trucks, he leaned over the side of his own car and watched the metal wheels. They clattered and thundered on the rails, the spokes were indistinguishable, having the appearance of disks. But at the bends this was altered. The car tipped bodily, the inner wheels left the tracks, and at once their momentum lessened. Then, though he could not see the individual spokes, the disk-like appearance was broken, telling him plainly, even if his eyes had not been sufficiently keen to actually see the fact, that the wheels and the track had parted company.
"Ah!" It was almost a groan that escaped him. In the few minutes in which he had been engaged in examining his own wheels the runaway train had gained on him by leaps and bounds. He could now hear the roar of its wheels above the rumble and clatter of his own, that and the buzz of the motor so busy beneath the bonnet. He cast his eye on either side, as if to seek safety there, and watched the fleeting banks of the Chagres River, bushes and trees, and abandoned French trucks speeding past. A gang of workmen came into view, and he caught just a glimpse of them waving their shovels. Their shouts came to his ears as the merest echoes. Then something else forced itself upon his attention. It was the figure of a white man, standing prominent upon a little knoll beside the rails, and armed with a megaphone. He had the instrument to his mouth, and thundered his warning in Jim's ears.
"Jump!" he shouted. "Jump! She'll be up within a jiffy!"
Within a jiffy! In almost less time than that; there were but two yards now between the small inspection car and the line of loaded trucks. Jim could see the individual pieces of broken rock amongst the dirt, could watch the fantastic manner in which they were dancing. He looked about him, standing up and gripping the side of the car. Then away in front, along the clear tracks. He thought of the passenger train, and remembered that he alone stood between it and destruction.
"I'll stick to this ship whatever happens," he told himself stubbornly. "If the train strikes me and breaks up the car, the wreck may throw it off the rails. Better that than allow it to run clear on into the passenger train. Ah! Here it is."
Crash! The buffers of the leading truck struck the motor inspection car on her leading spring dumb irons, and the buffet sent her hurtling along the track, while the shock of the blow caused Jim to double up over the splashboard. But the wheels did not leave the tracks. Nothing seemed to have been broken. The dumb irons were bent out of shape, that was all.
"Jump, yer fool!" came floating across the air to Jim's ear, while the figure of the man with the megaphone danced fantastically, arms waving violently in all directions.
But Jim would not jump; he had long since made up his mind to stick to his gun, to remain in this car whatever happened; for the safety of the passenger train depended on him. True, a telephone message might have reached the driver; but then it might not have done so. He recollected that at the switch where this mad chase had first begun there was no telephone station closely adjacent. It would be necessary for the man there to run to the nearest one. That would take time, while his own flight down the tracks had endured for only a few minutes, though, to speak the truth, those minutes felt like hours to our hero.
Bang! The cars struck him again, causing the one on which he rode to wobble and swerve horribly; the wheels roared and flashed sparks as the flanges bit at the rails. The bonnet that covered the engine, crinkled up like a concertina; but the car held the track. Jim was still secure, while the second buffet had sent him well ahead. Better than all, he realized that he was now beyond the steeper part of the incline, while his engine was still pulling, urging the car backward. If only he could increase the pace, if only he could add to the distance which separated him from that long line of trucks bounding after him so ruthlessly. Then a groan escaped him; for along the Chagres valley, where, perhaps, in the year 1915 a huge lake will have blotted out the site of the railway along which he flew, and where fleets of huge ships may well be lying, there came the distinct, shrill screech of a whistle. Jim swung round in an agony of terror. He looked along the winding track and his eyes lit upon an object. It was the passenger train, loaded with human freight, standing in the way of destruction.