It is said that the flow of a mighty river may owe its most radical change in direction to the chance thrusting of a twig into the current at some critical instant in the rise or fall of the flood. To the reincarnated Smith, charting his course upon the conviction that his best chance of immunity lay in isolation and a careful avoidance of the peopled towns, came the diverting twig in this wise.

On the second morning following the unofficial talk with Bartley Williams in the iron-sheeted headquarters office at the dam, a delayed consignment of cement, steel, and commissary supplies was due at the side-track a mile below the camp. Perkins, the timekeeper, took the telephone call from Brewster giving notice of the shipment, and started the camp teams to meet the train, sending a few men along to help with the unloading. Later, he called Smith in from the quarry and gave him the invoices covering the shipment.

"I guess you'd better go down to the siding and check this stuff in, so that we'll know what we're getting," was his suggestion to the general utility man; and Smith put the invoices into his pocket and took the road, a half-hour or more behind the teams.

When the crookings of the tote-road let him get his first sight of the side-track, he saw that the train was already in and the mixed shipment of camp supplies had been transferred to the wagons. A few minutes sufficed for the checking, and since there was nothing more to be done, he sent the unloading gang back to camp with the teams, meaning to walk back, himself, after he should have seen the car of steel and the two cars of cement kicked in at the upper end of the side-track.

While he was waiting for the train to pull up and make the shift he was commenting idly upon the clumsy lay-out of the temporary unloading yard, and wondering if Williams were responsible for it. The siding was on the outside of a curve and within a hundred yards of the river bank. There was scanty space for the unloading of material, and a good bit of what there was was taken up by the curving spur which led off from the siding to cross the river on a trestle, and by the wagon road itself, which came down a long hill on the south side of the railroad and made an abrupt turn to cross the main track and the siding fairly in the midst of things.

As the long train pulled up to clear the road crossing, Smith stepped back and stood between the two tracks. A moment later the cut was made, and the forward section of the train went on to set the three loaded cars out at the upper switch, leaving the rear half standing on the main line. From his position between the tracks there was a clear view past the caboose at the end of the halted section and beyond, to the road crossing and the steep grade down which the dusty wagon road made a rough gash in the shoulder of the mountain spur which had crowded it from the river-bank side of the railroad right of way. At the bottom of the steep grade, where the road swerved to cross the two tracks, there was a little sag; and between the sag and the crossing a sharp bit of up-grade made to gain the level of the railroad embankment.

One of the men of the unloading gang, a leather-faced grade shoveller who had helped to build the Nevada Short Line, had lagged behind the departing wagons to fill and light his pipe.

"Wouldn't that jar you up right good and hard f'r a way to run a railroad," he said to Smith, indicating the wholly deserted standing section of the freight with the burnt match-end. "Them fellies 've all gone off up ahead, a-leavin' this yere hind end without a sign of a man'r a flag to take keer of it. S'pose another train 'd come boolgin' 'round that curve. Wouldn't it rise merry hell with things 'long about this-away?"

Smith was listening only with the outward ear to what the pipelighter was saying. Somewhere in the westward distances a thunderous murmur was droning upon the windless air of the June morning, betokening, as it seemed, the very catastrophe the ex-grade-laborer was prefiguring. Smith stripped his coat for a flag and started to run toward the crossing, but before he had caught his stride a dust cloud swept up over the shoulder of the wagon-road hill and the portentous thunderings were accounted for. A big gray automobile, with the cut-out open, was topping the side-hill grade, and Smith recognized it at once. It was Colonel Dexter Baldwin's roadster, and it held a single occupant—namely, the young woman who was driving it.

Smith stopped running and transferred his anxiety from the train and railroad affairs to the young woman. Being himself a skilful driver of cars—and a man—he had a purely masculine distrust of the woman, any woman, behind a steering-wheel. To be sure, there was no danger, as yet. Turning to look up the track, he saw that the three loaded cars had been set out, that the forward section of the train had been pulled up over the switch, and that it was now backing to make the coupling with the standing half. He hoped that the trainmen had seen the automobile, and that they would not attempt to make the coupling until after the gray car had crossed behind the caboose. But in the same breath he guessed, and guessed rightly, that they were too far around the curve to be able to see the wagon-road approach.

Still there was time enough, and room enough. The caboose on the rear end of the standing section was fully a hundred feet clear of the road crossing; and if the entire train should start backward at the coupling collision, the speed at which the oncoming roadster was running should take it across and out of danger. Nevertheless, there was no margin for the unexpected. Smith saw the young woman check the speed for the abrupt turn at the bottom of the hill, saw the car take the turn in a skidding slide, heard the renewed roar of the motor as the throttle was opened for a run at the embankment grade. Then the unexpected dropped its bomb. There was a jangling crash and the cars on the main track were set in motion toward the crossing. The trainmen had tried to make their coupling, the drawheads had failed to engage, and the rear half of the train was surging down upon the point of hazard.

Smith's shout, or the sight of the oncoming train, one of the two, or both, put the finishing touch on the young woman's nerve. There was still time in which to clear the train, but at the critical instant the young woman apparently changed her mind and tried to stop the big car short of the crossing. The effort was unsuccessful. When the stop was made, the front wheels of the roadster were precisely in the middle of the main track, and the motor was killed.

By this time Smith had thrown his coat away and was racing the backing train, with the ex-grade-laborer a poor second a dozen yards to the rear. Having ridden in the roadster, Smith knew that it had no self-starter. "Jump!" he yelled. "Get out of the car!" and then his heart came into his mouth when he saw that she was struggling to free herself and couldn't; that she was entangled in some way behind the low-hung tiller-wheel.

Smith was running fairly abreast of the caboose when he made this discovery, and the hundred feet of clearance had shrunk to fifty. In imagination he could already see the gray car overturned and crushed under the wheels of the train. In a flying spurt he gained a few yards on the advancing menace and hurled himself against the front of the stopped roadster. He did not attempt to crank the motor. There was time only for a mighty heave and shove to send the car backing down the slope of the crossing approach; for this and for the quick spring aside to save himself; and the thing was done.