New York Sun/January 7, 1917
BOSTON may become a suburb of New York. One may be able to live in Boston and commute daily to New York, enjoying the intellectual stimulus of a home at the Hub and the satisfaction of battling with big business on Manhattan during working hours. Or one may spend the weekends at Chicago if a Manhattanite, with only a matter of a two-hours run separating these great industrial centres.
All this sounds a bit fantastic, no doubt, but there is the assurance of an engineering expert that this very thing is not only possible but eminently practicable. Prof. Boris Petrovik Weinberg, an instructor in mechanical engineering at the Imperial University of Petrograd, is the man that stands sponsor for this prophecy. At the recent Congress of Scientists held here under the auspices of the American Association for the Advancement of Science he went further than merely predicting this revolution in transportation, for he showed plans and a working model of the apparatus capable of hustling human beings from point to point at a, speed of 500 miles an hour.
There are probably a great many people who would prefer to let Prof. Weinberg make the first trial trip when his line is built full size, because the skeptic wonders just how the Muscovite engineer will be able to halt his trains after he gets them whizzing along at the rate of half a thousand miles an hour. And then there are those timid souls who fear being jarred by a collision at that high speed, quite forgetting that the cars, if built strong enough, would probably have much the better of it, like an armor piercing shell when opposed by a barrier of boards.
This whole idea of covering distance more quickly than is the practice now is inspired by the persistent restlessness of modern life. People want to go as fast as possible when bent upon reaching some desired point. The aeroplane has put the speediest of expresses somewhat in the shade, and it is possible to make a hundred miles an hour safely through the air. There are reasons for believing that the flying machine will soon be doing much better than this. Logically, efforts are being made also to increase the speed possible in land transportation.
Engineers have been working to realize this end for the better part of a quarter of a century, and with some measure of success, judged by short experimental or demonstrating lines. In most of these essays practical application on a commercial scale has been hampered by the expense. In other words, these extra rapid railway pioneers have been somewhat ahead of the times. But gradually the mechanical world has been developing accessories and bringing up the standard of economical electric current production to a point where practical application of these dreamers’ schemes is in a fair way to become an accomplished fact.
As part of the inter-building system of express communication on the Capitol reservation at Washington there is an 18-inch tubular installation by which it is possible to send books, papers and documents from the Library to the Capitol Annex and to and from the Capitol itself. The express matter is placed in large cartridges or capsules mounted on rollers and the carrier is speeded up by atmospheric impulse, driving the container forward through space that has been pumped out and thus formed into a partial vacuum. Considerable speed of transit is attained in this manner, and with a comparatively simple equipment.
This plant is mentioned in order that it may be plain in part how Prof. Weinberg is relying upon actual performance in planning a transportational system of much higher velocity and greater carrying capacity, for this Russian authority intends that passengers, not express matter alone, shall patronize his line. The model recently displayed here at the time Prof. Weinberg lectured consisted fundamentally of an iron tube in which he inserted a cylindrical car just big enough for a full grown person to rest in prone. The tube represented the tunnel or conduit of the system and the cylindrical car fitted into the passageway with a clearance all around.
There are no rails for the carriage to rest upon, the only point of contact being above the car, and that only a light one. In other words, the vehicle was freely suspended. This Prof. Weinberg accomplished by means of electromagnets exerting just pull enough to hold the car aloft and to servo to guide it along a single track, while keeping it from swinging laterally when advancing at full speed. The overhead magnets of course were designed to be energized in groups so that current would be consumed only in the Immediate neighborhood of the moving carrier.
Now a cylindrical car rushing on at 500 miles an hour would have to contend with a head-on air resistance which would call for the expenditure of a good deal of motive energy, especially if the air was confined in a tunnel. Prof. Weinberg has sought to dispose of this difficulty by creating a partial vacuum ahead of the vehicle after the manner of the Capitol pneumatic express. The main trouble is that in a long tube of the size proposed by the Russian engineer it would be very expensive to maintain a partial vacuum. Even if it were possible for him to divide the tube up into five or ten mile sections the pumping and piping equipment and the installing of automatic air locks would entail a tremendous outlay, and it is quite clear that he would require some such equipment in order to make his line mechanically practicable.
Theoretically it would be necessary for him to have air locks as he approached the end of a run, for in this way the resistance could be gradually increased and the cars brought without violence to a standstill. For propulsion the inrushing atmospheric air at the rear of the vehicle would provide the power, or the car could be drawn forward by magnetic attraction.
The thing that should interest New Yorkers most about this project is that native talent has gone good bit further than the point reached in the model shown by Prof. Weinberg. Within the past two or three years schemes of the same nature have been developed upon a much larger scale, and it is quite likely that more would have been heard of in a practical way but for the disturbing effect of the war in Europe. The postal authorities of both London and Paris were very much interested in some of these projects, for it was their desire to find ways to collect and distribute mail matter at speeds beyond the rates now commonly available.
About ten years ago Franklin Seltner Smith, an electrical engineer of Philadelphia, conceived a revolutionary form of self-propelled transporter. His ideas were so novel that he managed to satisfy all the experts of the United States Patent Office and to obtain his patent inside of four months from the date of application.
His system consisted fundamentally of a motor driven electrical vehicle without recourse to the ordinary spinning motor as prime mover. He ingeniously split up the elements of an electric motor and arranged them in such a fashion—part on the roadbed between the tracks and part under the car—that he was able to translate rotary motion into horizontal motion. In other words, his entire railroad became a great induction motor instead of so many separate revolving driving motors for his various cars.
His invention might have halted there had not the Electric Carrier Company of New York bought his patents and then spent couple of years or so in experimenting in order to whip the invention into practical form. Ultimately the company constructed a line 1,700 feet long consisting of tunnels, trestles, steep grades and inclines which pretty thoroughly demonstrated the running capacity of the system.
The vehicles employed were large enough to carry a thousand pounds and for normal service the cars made fifty miles an hour at full speed, although the same principles were applicable to a larger line having a maximum velocity of 100 miles an hour. This demonstrating plant was installed at Paterson, N. J., and was in service there for some months before the company went abroad to interest foreign postal authorities and express concerns.
It is not possible to give more than a very slight idea of how the Smith system works. An induction motor consists fundamentally of two parts: first, an iron ring inside of which, more or less like so many warts, are a number of electromagnets spaced equidistant. These magnets are excited by an electric current and become alternately positive and negative according to the way the current is fed to them. Technically this part of the motor is called the stator, because it is held stationary.
Within this big ring is a smaller cylinder of iron. This is slotted, and the slots are set with strips of copper which are insulated one from the other. Between this smaller ring and the wartlike magnets on the enveloping big ring there is an air space of a fraction of an inch.
When the magnets are progressively vitalized by an alternating current they exert a pull, and in this manner the central ring or rotor is made to revolve by reason of the magnetic flux. It will be observed that no electric current is fed into the rotor or central ring.
Now, imagine a circular stator broken at one point and flattened out so that it might be secured to the underside of a car. Instead of wartlike magnets, picture coils of insulated copper wire laid in grooves cut in the flattened iron ring, and suppose the iron body to be made of thin sheets bolted together instead of a single solid casting. Electrically there is thus provided the equivalent of the stator element of an induction motor, but remodeled as to shape, etc.
Next, another iron body built of similar sheets is grooved crosswise and in this is laid a thin lattice or grid of stamped copper. For all electrical purposes, this constitutes a rotor, and it was just this sort of element that Mr. Smith designed should be laid between the tracks of his railway from end to end.
When excited by a three-phase alternating current certain groups of the coils beneath the car are brought into service, and the field this induced reacts upon the rotor element laid between the rails. The rotor is fixed, and, of course, cannot move, and as a result the stator attached to the vehicle is pulled forward by the magnetism that jumps the quarter inch gap between the carrier and the rotor element on the roadbed.
The beauty of the system lies in the comparative simplicity of the equipment. The wheels simply serve to support the car, and progress is not hampered by slippery rails. Further, the vehicle goes up and down hill with uniform speed. When descending the mechanism serves as a brake and controls the rate of advance as if operated by clockwork. There is little to get out of order. Trailer trains carrying a total of 3,750 pounds have been run on the experimental line, and plans have been prepared for a line between New York and Philadelphia designed to carry first class mail, parcel post matter and express packages at the rate of a hundred miles an hour.
Possibly the most fascinating scheme is that developed by Emile Bachelet of Mount Vernon, NY, in order to overcome tractional friction. Mr. Bachelet found a way to float his car or vehicle aloft my means of repulsive magnetic impulses. Most people know enough about the ordinary horseshoe magnet to recall that two of them become mutually repulsive when their two south poles or their two north poles are brought closely together. Working upon this principle Mr. Bachelet discovered that certain non-magnetic metals, like gold, silver, brass, copper and aluminum are affected by the flux or field of an excited magnet and are repelled more or less energetically.
This is because of certain magnetic currents commonly known as Foucault or eddy currents. These currents have generally been a source of vexation to the practical electrician. Mr. Bachelet found a way to put them to helpful use. His experiments also brought out that aluminum, which is very light, is the non-magnetic metal most vigorously repulsed by the eddy current generated y an electromagnet.
Therefore Mr. Bachelet uses an aluminum platform or base for his car while the rest of the body of the vehicle is of iron. There is a reason for this combination of magnetic and non-magnetic metals.
Beneath the line along which his cars travel he has set a continuous system of electromagnets. These are energized in groups and are automatically brought into action by the advance of the car. Therefore there are always enough of them at work beneath the vehicle to exert forward thrust against the undercarriage of the aluminum platform or base, thus lifting it clear of physical contact.
This sheet of aluminum also insulates the iron body of the cars from the magnetic flux and prevents the underlying magnets from pulling the vehicle down. By energizing the levitating magnets in groups they are called into service only for a brief while as the car speeds on above them and for that reason can withstand an overcharge of current without being injuriously heated.
Mr. Bachelet effects the horizontal motion of his cars by means of solenoids—really another form of induction coil or magnet, which when excited by an electric current exert a strong tractive or attractive force.
These solenoids are placed at certain intervals along the path of the system and the advancing and passing vehicles automatically throw them in and out of service. The cars are really drawn forward by means of successive magnetic pulls and then carried onward by momentum until within the zone of influence of the next tractive magnet. This sounds as though the movement might be jerky, but the operations are so nicely tuned that the motion is really smooth.
Mr. Bachelet’s working model at Mount Vernon had a run of only fort feet, but within that limit the apparatus worked beautifully and he showed time and again that he could raise his model carrier with a designed load of sixty-five pounds a matter of a quarter of an inch above the repelling magnets. This was ample to float the vehicle in the air—in fact, all that is necessary is just a clearance-and so sustained, without frictional contact, the freely moving vehicle was easily drawn forward by the attractive pull of the solenoids.
Mr. Bachelet was satisfied by his experiments and his calculations that a system built along his lines would make it entirely practical ro cover the distance between New York and Boston in an hour’s time. This is somewhat slower than Prof. Weinberg’s project, but fast enough to satisfy all present-day requirements.
Mr. Bachelet went to France at the outbreak of the war, having previously aroused much interest among engineers and scientists in Europe. His invention is not intended by him to supplant general railway service and he does not intend it for the transport of passengers or heavy freight. His idea is a full-sized line or lines capable of carrying at the rate of 300 miles an hour unit carloads of express matter, mail, etc. weighing 500 pounds each.
Plainly a system of this sort because there is no physical contact with rails would not be bothered by the steepest kind of grade, and the inventor’s conception of such an installation is a tubular passageway supported high above the ground upon a single line of columns. His cars are tapered to a fine point at the end—in fact, there are virtually great big rockets—and because of their shape would offer a minimum of resistance to the enveloping air.
It is evident that Prof. Weinberg has been somewhat influences by Emile Bachelet’s works. The most suggestive part of all these ideas is the fact that many minds are making it possible for people to travel safely and surely day in and day out from point to point at speeds impossible of attainment upon ordinary railway systems.
(Source: Library of Congress, Chronicling America, http://chroniclingamerica.loc.gov/lccn/sn83030431/1917-01-07/ed-1/seq-56/)