Loud-speaker Systems on Railways

Abstract

LOUD-SPEAKER systems are being installed on an ever-increasing scale on railway platforms. A critical discussion of them by O. Vogel and K. Rothe is given in the second number for 1938 of the quarterly Review published by Siemens and Halske. Until quite recently, orders were shouted to the shunters by the shunting foreman or optical signals were employed. But these methods had certain drawbacks. Shouting was the most satisfactory, partly because it is independent of weather or illumination but mainly because it is heard by the shunters in any position. The transmission of orders by means of loud-speakers is an improvement as it ensures a uniform distribution of ample acoustical energy over the entire shunting yard, and all the requirements of safety and speed are satisfied. The old but satisfactory method of calling out times of departure in railway station waiting-rooms could never be entirely replaced by means of optical devices. The introduction of loud-speaker systems has now supplemented optical train indicators very helpfully and these devices are at the same time available for many other kinds of announcements. The authors also discuss portable loud-speaker systems suitable for race-courses, etc., where the normal traffic is small. To ensure the complete success of a stationary system, it is necessary to study the local conditions in every case. In halls, waiting-rooms and corridors, difficulties are often encountered owing to echoes.