Train Telephones

Radio Record, Volume III, Issue 4, 9 August 1929, Page 27

Train Telephones

Canadian Invention A FEW months hence the erack trains of the Canadian National Railways between Toronto and Montreal will be equipped with facilities allowing passengers two-way communication by long-distance telephone with any point on the North American continent. The basis of the new application of. the telephone lies in a combination of varrier current telegraphy and radio. [he Canadian National ‘Telegraphs have nerfected a system of carrier current telegraphy, which now practically spans the Dominion. ‘This system of telegraphy allows ten channels on each wire for message transmission. It was at one time called wired wireless, a confusing name. By means of the telegraph lines which run alongside the train tracks, it is now possible to tal from the moving train to any-dis-tant point. The call is put through by the passenger in the same way that any lonzdistance call is given. The operator on the train calls the nearest exchange, his voice leaping by means of a powerful radio transmitter the short distance from the train to the telegraph wires. In fact, the radio transmitter is little more than a powerful amplifier as used on the carrier current system, which induces the electrical signal, which was the voice, into the nearby telegraph lines. Since the carrier current system allows for voice transmission without interruption, the same results are obtained as over regular telephone lines. The call, once it has reached the telegraph wir.. alongside the track, is picked up at the nearest exchange.

_ The nerator there answers the train operator, for it all takes but a few seconds, and gets the number in the distant city. Then the procedure is like that of any telephone... It is also possible for a telephone subscriber: to -- eall up a train fitted with the apparatus. * M The Canadian National Railways will not attempt to control the use of the invention, which is to be made available to all railroads. — Use in England. RAtmwarx authorities in Dngland are watching closely the developments which have taken place in Canada in connection with the application of wireless telephony to the needs of the business passenger. Their intention is to experiment with the innovation here in the light of the results which are being obtained overseas, and should present indications be fulfilled the day is not far distant when a passenger from Glasgow to London will be able to carry on his business during the . journey through a telephone very simile lar te that on his: swn desk at home. The Dominion authorities have succeeded so far beyond their expectations, and are already planning tele ‘phone installations in a number of trains over short distances. Briefly, the procedure is .ne linking of the. train telephone with a switchboard in a rear coach. The operator there inquires for the number in the usual way, and communicates with the nearest receiving station by wireless, the call in turn being passed through to the ordinary telephone exchange. Calls from "terra firma" to moving trains © have also been put through satisfactorily by reversing the process.