WIRELESS TELEPHONE.

Taranaki Daily News, Volume LIII, Issue 316, 1 June 1911, Page 8

WIRELESS TELEPHONE.

FIRST INSTALLATION ON RAILWAY. The '•Railophone" installation which was opened at Stratford-on-Avon recently by Miss Marie Corelli represents an interesting and, probably, useful development in wireless methods of communication. Under the new system, which is Hie invention of Mr. Hans von Kramer, messages may be sent to or received from a train in motion, at no matter what speed, and, apart from the wiring of the carriages, an ordinary telephone instrument is all the apparatus required. As the train proceeds on its journey those who travel in it will be able to get into communication with the ordinary telephone and telegraphic systems •'on land''; and what is, perhaps, more important still, the officials in charge of the train —the engine-driver or the guard—will be in constant and tfirect touch with the officials who control the trall'ic from the signal-bexes. Thus the '■Railoplwne" will do for railway trains what wireless telegraphy has done for ships at sea, and it will reduce enormously the danger from accidents, whether the causes be human frailty or the vagaries of the elements. A non-technical explanation of the working of the "Railophone" may be given as follows: —An insulated cable is laid alongside the railway line, two or three fact away, and cither above or below the ground.' This cable connects with exchanges through which access is obtained to the telephonic and telegraphic systems of the country. The coach of the train which is to be the 1 sending and receiving station is surrounded with coils of insulated wire. A weak current of electricity from gen'rating cells passes through both the land and coach cables, as through a telephone or telegraph wire, but there is no mechanical contact whatever between the cables. The connection is what is called "wireless-inductive." A disturbance is caused, say, in the electric cur- , rent flowing through the cable on the coach by the waves of the human voice acting upon a telephone receiver. The pulsations of the current thus produced are by means of electro-magnetic induction reproduced in the cable which runs alongside the railway line. Tim process, can; of course, be repeated from the opposite direction, and messages can be sent and received simultaneously. A practical trial of the system on a small scale has already been made with complete success on a portion of the London, Brighton and South Coast Railway. The present test is being carried out on a larger scale 011 the ten milc.i of line between Stratford-on-Avon and and Kinoton on the Stratford-on-Avon and Midland Junction Railway.

As it has been said above, the importance of Mr. Von Kramer's invention lies in the effect it is expected to have upon the security of railway travelling. With the drivers of all trains, whether moving or at rost, in direct communication with the signal cabins, it will be possible even to rectify the mistake of a signalman and to triumph over some of the worst obstacles to the safe and regular movement of trains, such as fog and snow. Cumbersome hand-signalling in thick weathar by means of detonators placed on the rails would be entirely superseded. It is also proposed to extend the system so as to make it provide for automatic communication between engines which find themselves within certain distances of each other iipon the same line. In that way the risks of collision will be enormously reduced.