From The Electrical World
October 18, 1880
The Earliest Electric Railway.
It is probably a fellow-countryman of our own to whom we must look for the first experimental efforts toward electric traction. Late in the autumn of 1835 Thomas Davenport, a blacksmith, of Brandon, Vt., who had, with the enterprise characteristic of American inventors, worked through the patent office a broad claim covering the general principle of applying electromagnetic motors to machinery, turned his hand toward the building of an automobile machine and set up a small model which was exhibited in Springfield, Mass. Nothing, however, came of this spasmodic effort, and the first electric locomotive of any practical dimensions was the invention of one who to-day is perhaps the oldest living electrician, Robert Davidson, of Aberdeen, Scotland. Before passing to the very interesting experiments which he made, a word regarding his life may not be out of place. Robert Davidson was born in Aberdeen, Scotland, in 1804. As a young boy he evinced great interest in scientific pursuits, taking up, as was the habit of that time, specially the subject of chemistry. While engaged in his chemical studies he devised the form of galvanic battery which was afterward used in his locomotive. At that time the energies of every one who had any pretence toward scientific tastes were turned to electricity and magnetism, and like others young Davidson bent his energies in this direction, taking up astronomy also as a pastime, which was a favorite recreation of his during many years.
About 1839, in the period when the talents of Jacobi had been turned toward the propulsion of a boat by an electric motor, Davidson built his electric locomotive. He was filled with the idea, which, perchance, he may yet live to realize, if his days should be prolonged a few years more, that the electric motor could take a place for ordinary traffic on the railroads. He endeavored vainly to call the attention of the railway companies to the importance of his invention, and, failing in this, he turned from the study that in the hands of others has led to such prodigious results. The locomotive built by Davidson was, with other motor devices, exhibited at various points in England and Scotland during the three years subsequent to its construction and awakened keen interest wherever it was shown. Its final fate is a curious comment on the temper of the times.
After several successful trips had been made on the Scottish railways, and the machine was finally being taken home to Aberdeen, it was found in the engine house in Perth one morning broken by some malicious hands almost beyond repair. There was a strong feeling among the railway engineers that the "Galvani" was destined to supersede the machines with which they were familiar, and the evidence pointed to this as the reason for its destruction.
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Fig. 1 is a fac simile of a hand-bill describing the electromagnetic exhibition as it was shown by Davidson at various points in the United Kingdom. This particular handbill, printed, as will be seen, by an electric motor, was issued for the exhibition at the Egyptian Hall, Piccadilly, in 1842, just before the locomotive came to grief in the way we have mentioned. At the head of this poster is a representation of what was then the first electric railway ever constructed, for the " Galvani" was of no mean size, and, as we have seen, was given trial trips in actual railroad work where it attained a speed as high as four miles an hour. Its length was 16 feet, with a breadth of five feet, and its total weight was no less than five tons. It was operated, of course, by batteries placed in the locomotive car. Forty cells were in regular use, of a type always claimed by Davidson to be his own invention, although the claim was disputed by Mr. Sturgeon and Mr. J. Martin Roberts. The element consisted of plates of iron and of amalgamated zinc immersed in diluted sulphuric acid. In the locomotive battery the plates were each 12x15 inches, and the internal resistance must have been therefore very small.
The current from this battery was delivered to a motor of a very rudimentary, but tolerably effective, description, consisting of two cylinders of wood, fitted to the axles of four wheels. Eight electromagnets were placed at the bottom of the car in two opposite rows, and on each of the cylinders were two sets of iron bars parallel to the axles. These bars presented themselves as the cylinders rotated to the poles of the corresponding electromagnets opposite them. The electromagnets were divided into two sets, each one being supplied from a separate battery. At each end of the axles, just inside the driving wheels, were the commutators which made the necessary changes in the polarity of the magnets. In the "Galvani" shown herewith the power is apparently applied to the locomotive by a belt passing from the driving wheels of the motor to those of the locomotive proper.
The detail of the form of motor used by Davidson is well shown in Fig. 2, which is taken from a cut in the Penny Mechanic, of Sept. 23, 1843, whence also is derived the description of its action annexed. In Fig. 2, A and A' are two electro-magnets of the staple or horseshoe pattern made of the best wrought iron. Around these magnets is a copper wire covered with some non-conducting material, as cotton, silk, etc. In the largest of Mr. Davidson's engines a number of wires are arranged in one continuous bundle around which cloth or canvas is stitched. One end from the wire of A is soldered to the wire of A', which wire is again soldered to the connecting screw b. The other end of the wire from A is soldered to the socket of spring d and that of A' in like manner to the spring e. A cylinder of wood with a steel or iron shaft through its ends is arranged to turn freely in the bearings f f. Into this cylinder are inserted and fixed over it the pole pieces of iron C D E, which during the revolution must pass as closely as possible to the poles of the magnets, but without touching them. F is a fly-wheel attached to the cylinder, and G is the brake by which a galvanic current from the battery is led on and cut off alternately. It consists of a cylinder of wood, ivory or other suitable non-conducting material on the circumference of which is laid in a thin ring of brass with three projections in the direction of its axis. The ivory or wood has also three projections which fill up the spaces between the brass, and all being accurately turned together in the lathe a perfect cylinder is left, composed externally of a ring of brass extending half its length, and the remainder composed of three equidistant portions of ivory alternating with brass. The binding screw c is connected through the clamp g to the spring shown by the dotted lines in the lower part of the figure and presses upon the annular portion of brass, being always in contact with it. The springs dd, ee â€â€one for each magnet have knife edges at their free ends which press upon the portion composed alternately of brass and ivory. As these springs form a part of the metallic current necessary for the passage of the electricity, it follows that when they are not resting on a metallic surface no current can pass. The sets of wood between the portions of brass are so arranged that when the keeper rests opposite to the poles of the magnet the spring belonging to this magnet just rests on the ivory, consequently the current is broken and the magnetism ceases. At the same moment the opposite spring comes in contact with the metallic portion of the brake, and its magnet resists its effect and attracts the keeper next to it when the process is repeated. In the engraving the keeper D is nearly opposite A', the flywheel revolving in the direction of the arrow. The brake G, revolving with the cylinder and fly-wheel, has just passed one of its metallic portions from beneath the knife edge of the spring e, and another comes into contact with d. The current is therefore cut off from A', in which no magnetism now exists, and is led on to A which possesses its full power. The electricity is passing from the binding screw c along the clamp g to the spring through the annular portion of the brake to the projection on which the spring d rests, along which it travels to the wire coil around A, thence through the connecting wire to the binding screw b.
There are three dead points in this machine where the power acts equally in both directions. This is at the moment where the current is cut off from one magnet and led into the other. If, therefore,. it should happen to stand at this point when connection is made with the battery, the machine would need starting by hand. In any other position it will start of itself in the same way as would a steam engine, and when once in motion the momentum of the fly-wheel carries it past this point. Three, five, or seven keepers may be used, or four, six, or eight magnets, or there may be an odd number of magnets and an even one of keepers. It is scarcely necessary to mention that the power is increased by increasing the number of either. This description of the Davidson motor puts its actual method of operation in the clearest possible form.
The operation of the " Galvani" attracted much attention from the press of the period. The London Morning Advertiser, of Dec. 7, 1842, remarks in this connection: "Such being the progress of experiments, it is not being too sanguine to expect that some lucky genius' will at no very remote period, ascertain a means of adapting this extraordinary and easily developed power to supersede steam on railways, at the printing press, in vessels, at mills, etc." This opinion is evidently shared by the editor of the Aberdeen Banner, who remarked a couple of years previously : "That this power will at no distant date supplant steam, both in fixed and locomotive engines, will be apparent to any one who takes the trouble to scrutinize its capabilities; a power capable of being increased to any extent, occupying much less space, no fuel needed, no room for or risk of explosion." If either of the editors who made these prophetic remarks half a century ago should chance to be, like the inventor, still in the land of the living, the gigantic but somewhat tardy development of the power they so thoroughly appreciated ought to be a source of no little satisfaction to them. Aside from the locomotiveâ€â€which, we may remark, was given a practical trial on the Edinburgh & Glasgow Railway, where it successfully dragged the weight of six tonsâ€â€
Mr. Davidson also planned an electric carriage, and built a small model on which two persons were carried along the rough wooden floor of a large room. Such was, in brief, the history of the first electric locomotive of practical size that was ever built. Its fate has already been mentioned. The development of electrical traction, so earnestly predicted by some of those who saw the "Galvani," has been slower than they anticipated, but now, after the lapse of 50 years, has taken almost the place they predicted for it. A few years more may see the prophecy completely fulfilled. All in all, it is a bit of history which the electrician of to-day may well ponder over as his imagination turns to the possibilities of the next half century.
Its final fate is a curious comment on the temper of the times. After several successful trips had been made on the Scottish railways, and the machine was finally being taken home to Aberdeen, it was found in the engine house in Perth one morning broken by some malicious hands almost beyond repair. There was a strong feeling among the railway engineers that the "Galvani" was destined to supersede the machines with which they were familiar, and the evidence pointed to this as the reason for its destruction.
This blew me away... Seems the Luddites weren't only smashing cotton mills and threshing machines! They also trashed the worlds first EV...
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