Wireless Telegraphy in Railway Trains.

New Zealand Graphic, Volume XXXVI, Issue 11, 17 March 1906, Page 14

Wireless Telegraphy in Railway Trains.

EXPERIMENTS AT DERBY. The successful establishment of wireless telegraphic communication between ships at sea, or with the mainland, as exemplified by the various Atlantic liner*, has resulted in an attempt to utilise the system in another lamiiication of travelling, i.e., railway trains. This enterprise has be?n stimulated by the development of the long distance non-stop express traffic, such as that which is in operation between the various London termini and the Midlands and the North and West of England. The commercial value of such etheral conversation cannot be estimated. Its satisfactory accomplishment will enable the City man to keep in touch with his office while to the uttermost parts of the country at sixty in ks an hour, with a facility almost approaching that of his personal presence in the building. It will enable him to attend to those business developments demanding immediate attention, i n 1 which now have to be deferred until either his return or the establishment of postal communication, with the urgency desired. From the railway companies’ point of view the system will prove of incalculable value. At the present moment any instructions from headquarters for either the driver or guards of an express train, which is possibly engaged upon a nonstop run of 150 miles or more, cannot be transmitted until the arrival of the train at its destination. By wireless telegraphy, however, it will be rendered possible to apprise the officials at any time and point during the journey. Thus, for railway operation alone, the perfection of this project will appreciably contribute to the efficiency of ti e line. Repeated efforts have been made, and are still being made to accomplish this object on the Continent and in America. The results, however, have been far from satisfactory, and in some instances have been abandoned, owing to (lie impossibility of surmounting some of the greatest obstacles that have been encountered. Upon the Bclgi :u State lines experiments have been carried out with the Guarini-Cesar system, and signals have been received from a distance of 10J miles. In etchreal communicat’on for railway purposes several complex and apparently insurmount able difficulties have been encountered. The greatest of thes-_» is in connection with the aerial wires which project into, and collect from, the atmosphere the waves of electric impulses corresponding to dots and dashes of the Morse alphabet. For ordinary space telegraphic purposes this aerial wire at the transmitting ami receiving stations is carried upon a tall mast at a height of 40ft or more from the ground. The* impossibilty of carrying a mast of even moderate height upon a railway carr age will 'ue immediately realised. Wore there no tunnels or bridges the problem would be* considerably simplified, since it might be possible to carry an aerial wire, say, 10ft above' the roof. but as the height of the aerial wave is necessarily limited by the' gauge' < f the tunnels, a wire projecting only some 15 in above the* carriage roof c in be carried. The English experimenters, despite these disadvantageous circumstances, haver yet accomplished results which have* surpassed those achieved by m her investigators in the* same field in other countries. 'The experiments are being carried out upon the Midland Railway, the directors of which, in accordance with their characteristic progressive policy, are resolved to keep abreast with the times and bo in a position to introduce a perfected system whin the exigencies of commerce so demand. These researches are being undertaken at Derby by Mr. J. Rayers, the telegraphic. engineer to the railway, with Mr. Holt, who has been closely identi-

tied with the numerous ek ctricjl developments for varied purposes upon this line, as his first lieutenant. The system adopted is that conceived bv Sir (.diver Lodge and Dr. Alexander •Muirliead. as th,:* most’ suitable to the pecfrliar conditions ami requirements of railway working. And the experimenters have been foitunate in securing the assistance of l>oth Sir (diver Lodge and Dr. Muirhead in their efforts, both of these eminent scientists evincing great interest in the undertaking. As already mentioned the difficulty in connection with the aerial win* has constituted the gravest problem with the experimenters at Derby. The carriage (m ployed as a receiving station is a guard’s van of an obsolete type, and in order to test the idea under the most disadvantageous conditions th? carriage has not been modernised or specially prepared. The aerial wires are carried on poreci a in insulators, the height of the wins varying from nine to lift en inches above the curvature of the roof. Some idea of the magnitude of the problem being grappled with in this instance may be gathered from the fact that never before has so short an aerial wire been utilised in wireless telegraphyFrom the roof the wires are carried in a small cable through a special insulated fitting to the interior of the van, where tie receiving instrument is placed. Here the succeeding waves of dots ami dashes are separated and resolved into words upon a drum of paper, similar to those employed in a tape machine, the message being written by a Lodge-Mui rhea d siphon recorder, such as is used with marine cable instruments. The transmitting station is situated in a hut in a. field at Spondon, some one and a-ha If mile distant from Derby. The installation here comprises the apparatus for sending the messages into the air. Outside the cabin may be seen the aerial wire, which in this case follows somewhat upon the conventional lines, being supported upon masts about forty feet from the ground, and connected with the spark gap and coil for increasing the strength of the electrical impulse discharged from the transmitting instrument in the station. In common with other investigators in this direction, TvTr Sayers and Mr Holt have found that owing to the peculiar conditions prevailing enormous electrical energy is required to obtain successful conversation, especially to compensate for the short aerial wire used at the receiving carriage. Although th?y have despatched signals from this station which have been duly received at Derby, and can maintain communication if permitted to have unlimited resources, it is imperative for railway purposes that the work should be carried on within specified limits, involving no elaborations or departure from

existing designs in the rolling-stock, er the provision of special fittings alongside the permanent way. Success is ensured under such conditions, but the expense is prohibitive. For this reason Messis Sayers and Holt are rather confining their efforts to the devising of a simple and efficient means of operating, and are, as a consequence, exploiting virgin ground. For instance, they are endeavouring to reduce the length of the spark in the gap. which in many installations is as much as six inches, to one only a little more than an inch in length. So far they have employed a one and a-ha If inch spark. Even under these adverse circumstances, their experiments have lieen attended with considerable success. The van containing the receiving apparatus lias been attached to trains running within a radius of about twelve miles of Spondon. and signals have been satisfactorily received from varying distances within this range. Tests have been made at speeds between twenty-six and forty miles per hour, and the signals transmitted from the Spondon station have been faithfully recorded. The signals have naturally varied in character, some being stronger than others, a result due to the fact that the problems concerning the aerial wire and. the extent of the electrical energy required have not yet been completely overcome. Perfection of these two factors, however, must accompany this development of the experiments. and when this end is attained then a decided step will have been made towards commercial practicability. Innumerable other difficulties of a technical nature, with which the problem literally bristles, have been encountered, but it is satisfactory to learn that as a result of their prolonged efforts Messrs Sayers and Holt have accomplished more convincing results than any other investigators in the same field. It would be a bold speculation to state when ethereal telegraphic communication with express trains will become an accomplished fact, but in view of the stage at which these investigations have arrived, it must be in the near future. The Midland Railway, in taking time by the forelock, will be found ready to supply the public travelling over their system with this convenience when the necessity arises.