Then began an exciting race between his car and the spoil train; for the latter was composed of many long, heavy trucks, all laden to the brim with rock debris, consequently the smallest incline was sufficient to set them in motion if not properly braked. Now, when the whole line had broken adrift from its engine, and had run on to the Culebra incline, the weight told every instant. The pace soon became appalling, the trucks bounding and scrunching along the tracks, shaking violently, throwing their contents on either side, threatening to upset at every curve, gained upon Jim's car at every second. "I'll have to jump if I can't get clear ahead," he told himself. "But if I can only keep my distance for a while the incline soon lessens, when the pace of the runaway will get slower. But that man was right; she's coasting so fast, and has so much weight aboard, that the impetus will take her best part of the way to Gatun." Once more it was necessary for Jim to do as he had done aboard the motor launch. His ignition and throttle levers were pushed to the farthest notch. He was getting every ounce of power out of his car, desperately striving to keep ahead. But still the train gained. They came to a curve, our hero leading the runaway by some fifty yards, and both running on the tracks at terrific speed. Suddenly the inside wheels of the inspection car lifted. Jim felt she was about to turn turtle and promptly threw himself on to the edge of the car, endeavouring to weigh her down. Over canted the car till it seemed that she must capsize. Jim gave a jerk with all his strength, and slowly she settled down on to her inside wheels again, clattering and jangling on the iron track as she did so. Then he glanced back at the dirt train racing so madly after him. "She'll be over," he thought. "She'll never manage to get round that bend at such a pace." But weight steadies a freight car, and on this occasion the leading trucks at least managed to negotiate the curve without sustaining damage. The long train, looking like a black, vindictive snake, swung round the bend, with terrific velocity, and came on after him relentlessly. Then, as the last truck but one reached the bend, there was a sudden commotion. The dirt it contained heaved spasmodically and splashed up over the side; it seemed to rise up at the after end in a huge heap, and was followed by the tail of the truck. The whole thing canted up on its head, then swayed outwards, and, turning on its side, crashed on to the track running along beside it. There was a roar, a medley of sounds, while the actual site of the upset was obscured by a huge cloud of dust. "That'll do it," thought our hero. "If we have any luck, that upsetting truck will pull the rest of the cars off the road, and bring the whole train to a standstill."