Tom Swift's first thought was one of thankfulness. Thankfulness that he did not have a drag of fifty or sixty steel gondolas or the like to add their weight to the down-pull. The locomotive's own weight of approximately two hundred and seventy tons was enough.

For when the inventor pushed Ned aside and tried to handle the controllers properly, he found them unmanageable. There was not a chance of freeing them and getting power on the brakes. The Hercules 0001 was hacking down the mountain side with a speed that was momentarily increasing, and without a chance of retarding it!

The young inventor at that moment of peril, knew no more what to do to avert disaster than Ned Newton himself.

It flashed across his mind, however, that others beside themselves were in peril because of this accident. The fast express from the East that should pass Half Way at four-thirteen, might already be climbing the hill from Hammon. Hammon, at the foot of the grade, was twenty-five miles away. Nor was the track straight.

If the operator at Half Way did not see the runaway locomotive and telephone the danger to the foot of the grade, when the Hercules 0001 came tearing down the track it might ram something in the Hammon yard, if it did not actually collide with the approaching westbound express.

Such an emergency as this is likely either to numb the brains of those entangled in the peril or excite them to increased activity. Ned Newton was apparently stunned by the catastrophe. Tom's brain never worked more clearly.

He seized the siren lever and set it at full, so that the blast called up continuous echoes in the forest as the locomotive plunged down the incline. He ran to the door again, on the side where Half Way station lay, and hung out to signal the operator who had so recently given him right of way on this stretch of mountain road.

"We're going to smash! We're going to smash!" groaned Ned Newton.

Tom read these words on his chum's lips, rather than heard them, for the roar of the descending locomotive drowned every other sound. Tom waved an encouraging hand, but did not reply audibly.

Meanwhile his brain was working as fast as ever it had. He had instantly comprehended all the danger of the situation. But in addition he appreciated the fact that such an accident as this might happen at any time to this or any other locomotive he might build.

Automatic brakes were all right. If there had been a good drag of cars behind the Hercules 0001, on which the compressed air brakes might have been set, the present manifest peril might have been obliterated. The brakes on the cars would have stopped the whole train.

But to halt this huge monster when alone, on the grade, was another matter. Once the locomotive brake lever was jammed, as in this case, there was no help for the huge machine. It had to ride to the foot of the grade--if it did not chance to hit something on the way!

And with this realization of both the imminent peril and the need of averting it, to Tom's active brain came the germ of an idea that he determined to put into force, if he lived through this accident, on each and every electric locomotive that he might in the future build.

This monster, flying faster and faster down the mountain side, was a menace to everything in its track. There might be almost anything in the way of rolling stock on the section between Half Way and Hammon at the foot of the grade. If this thunderbolt of wood and steel collided with any other train, with the force and weight gathered by its plunge down the mountain, it would drive through such obstruction like a projectile from Tom's own big cannon.

Tom realized this fact. He knew that whatever object the Hercules 0001 might strike, that object would be shattered and scattered all about the right of way. What might happen to the runaway was another matter. But the inventor believed that the electric locomotive would be less injured than anything with which it came into collision.

At any rate, thought of the peril to himself and his invention had secondary consideration in Tom Swift's mind. It was what the monster which he could not control might do to other rolling stock of the H. & P. A. that rasped the young fellow's mind.

The grade above Half Way had few curves. Tom soon caught the first glimpse of the station. Would the operator hear the roar of the descending runaway and understand what had happened?

He leaned far out from the open doorway and waved his cap madly. He began to shout a warning, although he saw not a soul about the station and knew very well that his voice was completely drowned by the voice of the siren and the drumming of the great wheels.

Suddenly the tousled head of the operator popped out of his window. He saw the coming locomotive, the drivers smoking!

To be a good railroad man one has to have his wits about him. To be a good operator at a backwoods station one has to have two sets of wits--one set to tell what to do in an emergency, the other to listen and apprehend the voice of the sounder.

This Half Way man was good. He knew better than to try the telegraph instrument. He grabbed the telephone receiver and jiggled the hook up and down on the standard while the Hercules 0001 roared past the station.

It did not need Tom's frantically waving cap to warn him what had happened. And he remembered clearly the fact of the expected westbound flyer.

"Hammon? Get me? This is Half Way. That derned electric hog has sprung something and is coming down, lickity-split!

"Yes! Clear your yard! Where's Number Twenty-eight? Good! Side her, or she'll be ditched. Get me?"

The voice at the other end of the wire exploded into indignant vituperation. Then silence. The Half Way operator had done his best--his all. He ran out upon the platform. The electric locomotive had disappeared behind the woods, but the roar of its wheels and the shrill voice of its siren echoed back along the line.

The sound faded into insignificance. The operator went back into his hut and stayed close by the telephone instrument for the next ten minutes to learn the worst.

If the operator's nerves were tense, what about those of Tom Swift and his chum? Ned staggered to the door and clung to Tom's arm. He shrilled into the latter's ear:

"Shall we jump?"

"I don't see any soft spots," returned Tom, grimly. "There aren't any life nets along this line."

Ned Newton was frightened, and with good reason. But if his chum was equally terrified he did not show it. He continued to lean from the open door to peer down the grade as the Hercules 0001 drove on.

Around curve after curve they flew. It entered Ned's tortured mind that if his chum had wanted speed, he was getting it now! He realized that two miles a minute was a mere bagatelle to the pace now accomplished by the runaway locomotive.