THE RAILOPHONE

New Zealand Times, Volume XXXIII, Issue 7870, 4 August 1911, Page 8

THE RAILOPHONE

An application of induction telephony to the purposes of communication between moving trains and signaJ-boxes, or stations. has been, made by Mr H. von Kramer, who is introducing his system under the name of the radiophone. A demonstration of the apparatus was given at Ltrat-ford-on-Avon, an installation, covering about three miles of line, having been la ; d down on the Stratford-on-Avon and Midland Junction Railway. The arrangement is very simple, and consists merely of an Insulated line-wire carried parallel to the running rails, and a lew feet from them, and a closed coil of about a dozen tarns carried bv one of the coaches of a train. The closed coil is connected to a telephone Instrument in such a way that the current pulsations, caused by speaking, pass through it, aud arc inductively reproduced in, the line-wire, which is connected to a receiver in the signal-cabin. The return circuit of the Hue-wire is made through the running rails. In the actual installation on trial at Stratford-on-Avon two coils are used on the coach, one being connected to the transmitter, and the other to the receiver. The coils lie in a horizontal plane and completely encircle tiift coach, being carried below the footboards aud protected with wood-casing. The telephone instruments arc placed in a bos in which the operator sits, and which is padded to deaden, sound. An ordinary transmitter and receiver are used, the former working with from eight to ten dry cells. The 'line-wire of the installation is run partly above ground and partly below, in the former oasc being laid in wooden troughing and insulated with bitumen, and in the latter earned on short wooden poles. It is suggested that the raiiophone system may form the basis of a signalling arrangement for trains, and it is stated that a relay has been developed which can be operated by the impulses picked up by the train and arranged to control a system of cao signals. or. if necessary, the brakes. No details of the relay are available at the preseat moment, but it in clear that somewhat special features would be necessary in an appliance which, while operating with a telephone current, would not at

the same time prove too delicate to stand the vibration of a. train in service.