At 15:42, as Rawolle named it, but at 42 minutes past 3, as Cobb persisted in calling it, their arrangements had been completed and they were at the front entrance to the Occidental.

At the curb stood an elegant four-seated carriage of very light construction, with a driver upon the seat. There were no horses attached to the vehicle, which was very low in build, and with wheels of fair size. The driver sat in the rear, on a sort of raised single seat, with a small wheel, like a tiller-wheel, in front of him.

It was an electric drag, with the storage batteries underneath the seat. There were many passers-by at the time, but, thanks to Rawolle’s care, none knew who were getting into the carriage, else there would have been a crowd in a few minutes.

Taking their seats, the driver started the current, and the carriage rolled rapidly down toward Market street.

“What do you think of this for a carriage, Mr. Cobb?” asked Rawolle.

“It is a most decided advance upon anything we had in old days,” the other returned, looking admiringly over it. “This is, no doubt, an electric carriage?”

“It is an electric drag, and the style of all the first-class carriages in the city, except those which are used for hill travel. These carriages run up grades of three hundred feet to the mile with ease.”

“Are they expensive? and how long will their batteries last?”

“No; far less expensive than horses. The batteries, or accumulators, are very small, but with great power. The weight carried by such a carriage as this, in accumulators, is about fifteen pounds, and the energy is the equivalent of two horses for six hours, or a greater number of horses for a less time. The accumulators are charged at the rate of about fifty cents per set, which is a six-hour run. The great saving is that when the carriage is not in use, there is no expense.”

The carriage was going at a good round gait, but the motion was easy and steady.

Passing into Market street, Cobb was astonished at the magnificence of the buildings. He could not remember ever having seen a single building then standing as being there during his time. The architecture was grand in the extreme; beauty was not lacking, but was combined with strength.

He saw horses, electric motors, and cable cars, but the latter no longer ran upon tracks on the street; the trucks were all underneath the roadbed, while the cars were held aloft by thin but strong steel supports. The cars, moreover, were lighter built and set closer to the ground.

He saw no horse-cars. The pavement was everywhere of the same material—clean, smooth, and elastic; and he rejoiced to think that at last mankind had awakened to the fact that it was not only cruel, but costly, to cause horses to run upon cobble-stones, and pavements of similar construction. He did not have time to note all the many changes which had taken place and then in view, ere the carriage stopped at the gate of a most imposing edifice.

Alighting from his seat, Rawolle assisted him down, saying:

“Here we are, Mr. Cobb.”

Having gotten out, they all went into the depot, for such Cobb was informed it was. He was surprised at the grandeur of the building. It far exceeded anything he had ever seen for similar purposes. Rawolle took him around and showed him the various waiting, toilet, dining, and other rooms.

The depot was on the site formerly occupied by the old station, at the corner of Third and Townsend streets.

Passing into the main hall, he perceived a stream of people coming from the left. The interior of the depot, after passing through the main hall, was a vast space with a great arched roof. The ground was paved with marble slabs, and divided by iron fencing into five large compartments; the first running from side to side of the building, while the others were set at right angles to it. Each of the four divisions had a great slot or opening through its floor, of about two hundred feet in length by twelve in width. The last opening was filled by a train which had just arrived.

The people were flocking out, and through the gates into the main hall, or, as Cobb called it, the fifth compartment.

His attention was riveted to the train as it stood upon the track. It was so different from anything in the railway line that he had ever seen before, that he was most anxious to learn something about it.

It was a train of five cars, each about forty feet long, and of circular construction. It rested upon innumerable little runners, and was set quite close to the ground. The end of each car was a huge circular disc of a diameter a little greater than that of the car, and having an elliptical opening of some seven feet in the long diameter. Along each side of the cars was another set of runners, while two more sets were upon the tops.

There were no windows to the cars, and they looked plain iron cylinders of vast size, set upon a lot of little iron legs.

Standing there a moment, Cobb watched the last passenger leave the hall, and soon heard the guard cry for the gates to be closed. Almost immediately the gate of that compartment was dropped, and he saw the huge train sink into the opening and disappear from sight.

Turning toward Rawolle, who had been watching him with a curious expression, he exclaimed:

“Rawolle, tell me what kind of transportation is this that I have just seen? It is something that beats my time, and I am at a loss to understand its working.”

“I do not wonder at your expression of astonishment, my dear boy;” then pointing toward the third opening, and looking at his watch, he continued: “You will see a similar train soon come up; watch carefully.”

Cobb did as directed, and in a moment saw a train of cars, in all respects similar to the train which he had seen disappear through the left-hand slot, rise from below. It came up gradually, and at last stood, as its mate had stood, flush with the floor of the room; but, unlike the former, it had no passengers to disembark. There it stood, silent and empty.

As the train reached the level, a placard was dropped from the top of the gate, bearing the words “Omaha, 16 D.,” in large letters.

“That is our train, Cobb,” said Rawolle, following the eyes of the other to the sign. “Let us get our traps together and get aboard.”

Approaching the gate, which had by this time been thrown open, and through which many people were passing, Rawolle showed the tickets, and the three men passed in and proceeded along the train to the second carriage. Curbing his impatience to learn more of his peculiar surroundings, Cobb followed Rawolle and Lyman into the car.

The car resembled the sleepers of former years, except that it was decorated in a grander style and had no windows. It was lighted by electric lamps, which made it as bright as day. The seats were somewhat differently constructed from those of the old kind, but the general appearance of the interior was quite the same.

A porter met them at the door, and after seeing their tickets, showed them to their section.

Throwing down his grip and coat, Rawolle said:

“Come, Cobb, there are a few minutes before the train leaves; let me show you about.”

“All right; I am at your service.”

“Mr. Cobb, I think you will find this train a most decided improvement upon those used in your day,” remarked Lyman. “Of course it is old to us, but I can imagine your surprise at many of the improvements you see about you.”

“Right you are,” returned Cobb; “there are so many new and peculiar contrivances around me that I am like a man who has just awakened in a land of fairies. I am not going to be too curious, but await developments, for I have no doubt that I will be satisfactorily informed concerning them all at the proper time.”

“This is the pneumatic train,” continued Lyman, motioning toward the train on the track.

“Now, hold on,” interrupted Rawolle, quickly; “all in good time. It is better to explain all this to Mr. Cobb in detail. Let him first see what there is to be seen, and then we will explain it to him afterward.”

Passing into the first car of the train, Cobb was shown the smoker; and here he found a hundred little inventions which had been made with a tendency to increase the comfort of the traveler across the continent.

“This is the Central Pneumatic, or Continental Express,” said Rawolle, “excepting the baggage-cars; they are below, receiving the baggage as it arrives.”

At this moment the sound of a deep-toned gong was heard, and Rawolle said they must hurry back, as that was the signal for the gates above to be closed preparatory to starting.

A moment later, they were all standing on the platform between the cars, and an instant afterward the whole train began to sink, and soon had left the opening far above them. The train rested upon a sort of hydraulic lift which came to rest as soon as it had reached a level some twenty-five feet below the floor of the depot. They were in a subterranean chamber, or rather a series of chambers, which were brilliantly lighted by electric lamps.

There were many tracks in every direction, with moving trains upon them.

Leaning out to the side of his car, Cobb saw an engine, or what he took to be such, move up and couple to his train, and soon he felt it being rapidly hauled away.

This subterranean labyrinth of roads was similar to the yard of a great railroad center. Men were in every direction, turning switches, coupling cars, clearing tracks, etc.

Their train was taken about a mile underground, and then run into a great iron tunnel. A peculiar sighing sound, like that of a great storm a long distance off, now fell upon his ears. Turning inquiringly to Rawolle, he asked the meaning of it.

“Air—sucking air,” was the answer.

“Yes; I presumed as much,” Cobb returned, piqued at the brevity of the answer.

“Observe all you can, Mr. Cobb, for you have but a few minutes more. I will explain it after we are in the car,” noticing the impatience of the other.

The tunnel in which they then were was, like the great lower chambers, well lighted up. At one side, and opposite to where they stood, was a recessed chamber containing what appeared to be very powerful machinery. Cobb saw the motor disconnect from the train at this point, but he was not permitted to notice further the working of this most remarkable invention, for the guards ordered them into the car, and the door was closed and bolted.

Going back to the smoker, they lighted their cigars and settled themselves comfortably among the cushions.

“Now,” exclaimed Rawolle, sending up a cloud of smoke, “now I am at your service.”

“Then, tell me all about that which I have seen,” Cobb impatiently asked. “Don’t you see how anxious I am?”

“Very well. Let us commence at the beginning: In the first place, this that you have seen is the pneumatic railway. Its official designation is ‘The Central Pneumatic.’ There are, in the United States, quite a number of these roads. From San Francisco run three, as follows: one to the north, one to the south, and this one to the east. Here is a map showing all these roads in the country;” and he took from his pocket an official railway guide, and handed it to his listener. “As the word implies, air is the motive power—not compressed, but atmospheric pressure against a surface, on the other side of which a partial vacuum has been created by exhaustion. This is the method in the tunnels only. After the trains leave the great tunnels, they are moved about the yards, which you saw were all underground, by electric motors. Hydraulic lifts take them up to the station and lower them again. Everything is underground until the train rises through its opening in the floor of the depot. When the guard ordered us into the car, and bolted the door, we had been pushed into the receiving section of the main tunnel. The main tunnel is a complete iron and stone structure, extending between San Francisco and Salt Lake without break. At Salt Lake are the engines which exhaust the air from this tunnel, the pressure of the external air being the propelling power to move the train forward to its destination. The tunnels are twelve feet in diameter, and the rear car of the train carries a shield, or end-piece, which almost fills the cross-section of the tunnel; in fact, there is but the hundredth part of an inch between the edge of the shield and the interior side of the tunnel. The engines, as I said, are constantly pumping out the air, but this is carried to such a degree that the external pressure on the tubing of the tunnel is always under one pound per square inch. A series of valves at the end of the tunnel farthest away from the engines, permits ingress to the air which acts against the rear end of the train to move it forward. The train is first placed in a movable section of this tunnel, and, everything being ready, this section is moved upon rollers into connection with the main tunnel—a sort of valve action. The instant this is done, the air is permitted to enter in front of the train, and then gradually shut off until, the train having acquired its normal speed, the valves are closed altogether, and the air permitted to enter the tunnel behind the train only. It is very simple, and works to perfection. There are inlets through the rear shield of the train, to which are connected tubes running to each car. These are the air-tubes of the train. As the pressure of the air against the rear shield is one pound per square inch, a like pressure is exerted at the orifice of each tube; but, as there is no resistance to its ingress, it passes through into the cars, causing an internal pressure of the atmosphere of nearly one pound per square inch. Valves opening in front of the rear shield, and at a pressure of a little less than one pound per square inch, permit of the escape of the vitiated air into the tunnel ahead of the rear shield. Thus a steady stream of pure air is maintained throughout the whole train. The trains are received at their destination upon compressed-air receivers, and gradually come to a stand-still. At Salt Lake, forty five minutes are allowed for this train to transfer passengers and for supper, and then the train starts onward for Omaha. At that city the train is again made up and starts upon its new course for Chicago, New York, New Orleans, Minneapolis, or other point, as the case may be. Now, our train was placed, as I said, in an auxiliary tunnel, which was, by simple mechanical means, brought into position as the segment of the main tunnel. You, of course, noticed that each car was fitted at its end with a circular disc, covering the whole end excepting the door which leads into the next car. Well, this circular disc covers the end car completely. When our train was brought into the main tunnel, the pressure upon its end-section would have been, if suddenly exerted, so great that we would have started off with a great shock, but the air is allowed to enter behind the car gradually, as I have explained. When the full momentum is reached the full pressure of the external air is allowed to exert itself against the end of the train.”

“And how long does it take to gain this full momentum?” Cobb asked.

“But a few moments. Are you aware that you are now traveling at the rate of two hundred and forty miles per hour, or four miles per minute?”

He smiled at the look of incredulity which his words evoked. Cobb was loath to believe he was in earnest, for he felt no shock of starting, nor did he experience any motion such as he would naturally associate with such a terrific speed.

“Such a rate must make the wheels spin,” from Cobb.

Lyman looked at him, while Rawolle burst into a laugh.

“I do not see anything to laugh at,” the other retorted, a little nettled.

“No, no, Mr. Cobb; do not be displeased. We really meant no discourtesy; but your remark is not what you would have made had you thought a moment, for we know you to be a man of education. We do not use wheels on the pneumatic roads. These trains run upon the many little runners which you saw under the cars. Were we to use wheels,” he continued, after a pause, “centrifugal force would tear them into pieces in no time. Take the case of a wheel four feet in diameter: the circumference of such a wheel is a little over twelve feet. At the rate of four miles per minute, it would have to revolve 1,760 times. No wheel that can be made would stand such a test. It would fly into fragments inside of the first mile. A wheel of the above dimensions and at that rate of revolution would have a centrifugal force equal to 1,000,000 pounds. Now, as the centripetal force is the tensile strength of the material only, and that of the best steel wire only 160,000 pounds, it will readily be seen that the centrifugal force would instantly cause the wheel to fly into fragments.”

“You are right,” Cobb answered, going over the figures in his mind. “Wheels would never do; I can see it plainly.”

“Even were we to use a smaller wheel to decrease the centrifugal force, we would have to increase the number of revolutions, so there would be no gain in so doing. Our trains run upon two peculiarly constructed rails, and the runners are flanged to exactly fit the rail. There is, in addition, on either side of the tunnel, another rail of similar shape, while upon the upper part are two more. The car has runners for all of these rails, and the position of them is such that the car cannot jump the track, or swing or sway from side to side. It travels as if in a groove, and the little runners, separate from one another, conform to the curves of the tunnel.”

“It must take powerful engines to exhaust the air from such a long tunnel, does it not?”

“Yes, very powerful ones. But what is different from any other mode of propulsion, the same engine can do as much service for a line 2,000 miles long as for one of 200 miles in length, rate of speed being the same. The reason for stations at intervals of about 500 miles, is because more trains can be kept in motion on medium short lines than on very long ones. There are at Salt Lake, at the receiving end of this line, fifteen engines of 5,000 horse-power each; ten at work all the time, with five in reserve.”

“A pretty strong set of engines for a single railroad, I would say; and a costly motive power, too.”

“Not so costly as you would think,” he returned. “If you take into consideration that these engines are worked by electricity, and not by steam, and that the electricity is furnished by water-power, you will perceive that they can be worked quite cheaply.”

“Give me some of the statistics, please,” said Cobb.

“Certainly. The tunnel is twelve feet in diameter, which gives it a superficial area of 17,712 square inches. Now, at a pressure of one pound to the square inch, a train has a pushing force at its end of the same number of pounds. A train weighs 50,000 pounds. The heaviest grades on the line are some of two hundred feet to the mile. The power required to push this train up such grades is 2,000 pounds, for the matter of friction is not taken into consideration, being, by our arrangements, reduced to the minimum. Thus the pressure in the tunnel is always sufficient to move eight trains. If a train moves four miles in a minute, then the volume of air in the tunnel to be displaced is equivalent to the area multiplied by the length, which gives 2,600,000 cubic feet; but, under a pressure of one pound, this volume becomes 3,000,000. The pumps at each station are ten in number, each of thirty feet diameter by ten-foot stroke, with a volume for each of 7,060 cubic feet. These pumps make thirty strokes per minute, which is equivalent to sixty single strokes. Thus the volume of air displaced by the pumps is 7,060 × 60 × 10 = 4,236,000 cubic feet, an amount far in excess of that required.”

“Then, judging from your remarks, there is practically no limit to the speed which can be obtained by this method of propulsion?”

“On the contrary,” Rawolle returned, “the limit is reached when the friction on the runners generates such an amount of heat that they begin to disintegrate. At three hundred miles per hour they become very hot. As it is, we have to use a very peculiar kind of alloy for runners, and during all the time of running, keep a stream of oil flowing just in front of each runner.”

“But,” asked Cobb, “does not this oil congeal upon the rail in cold weather?”

“It does, most certainly; but there are little scrapers just in front of each runner which cut away the congealed oil to the merest fraction of an inch from the rail. These cutters must, by the train running between its upper and lower rails, always be just so far away, and no farther, from the rails.”

It seemed to Cobb that he could advance nothing but what this man had a ready explanation for its action or cause. It was, indeed, a most marvelous invention. Here he was traveling at the rate of two hundred and forty miles per hour, and scarcely felt the motion.

“Where is the electricity for these powerful engines generated?” he inquired.

“For the Central and Northern, as well as for the Pacific Pneumatic and Mountain lines, the dynamos are at the Shoshone Falls, in Idaho. These falls furnish an immense water-power, estimated at over 300,000 horse-power. The current is delivered at the station in great cables of peculiar construction, and well insulated.”

“Do you have any accidents on the roads? At such a rate of speed, an accident would be fraught with frightful consequences,” Cobb continued.

Rawolle smiled as he said:

“During your time, accidents were not uncommon—in fact, I might say quite common, judging from the old chronicles; but we have never had an accident yet upon any of our lines. There have been, of course, breaks and delays; but as each train is in communication with each other, and with each end, and with the chief of the exhausting department, everything is known at all times regarding the position of trains and their condition.”

Striking a match, he continued:

“No train could run into the one ahead of it, for the reason that there will always be a cushion of air between them; and further, were any ordinary number of runners to break at one time, the train would not be affected by the loss.”

“How wonderful, yet how simple!” exclaimed Cobb, lost in admiration. “But I am at a loss to understand why the people of my time did not discover and put into operation the same project.”

“Perhaps someone did discover the principle, but had not the means to test his theory,” Rawolle returned.

“How long has this system been in operation?”

“About thirty years,” he replied, after a moment’s thought.

“Tell me one other thing,” said Cobb; “has the pneumatic railroad superseded all other kinds?”

“Oh, no; by no means. There are railroads all over the United States, and very much the same style of your day, excepting the great improvements which have been made, and also the one other most important fact, that all engines are run by electricity. The pneumatic lines are through lines only, and are for rapid transit between very distant points, and only for passengers, mail, and express. All freight is sent by the other roads.”

“Then, the towns, excepting the great centers, are connected by electric railroads for inter-transportation?”

“Yes; the pneumatic is only an auxiliary to the rest of the roads—a means only of overcoming great distances quickly.”

“And what is considered good speed for the electric roads?”

“Seventy-five miles per hour for passenger trains, and fifty for freights.”

“Then, they must be very differently constructed from those of old,” exclaimed Cobb.

“They have very different roadbeds, and, of course, different engines. But enough for the present,” looking at his watch. “It is 18 dial, and we had better get into the sleeper and prepare for supper, for we are almost at Salt Lake.”