A survey of railway signaling and control

Railway signaling originated from the basic needs of safety, but its development has permitted the exploitation of wider facilities, in the form of considerable economies and increased efficiency, coupled with the attainment of higher speeds and improved control. It is closely supported by telecommunications techniques, both in ancillary functions and in characteristic railway communication networks, using land and radio transmission media. Signaling is based on the principle of "fail-safe" and complete reliability; at first it was effected by mechanical means, but subsequently supported and replaced by electrical means, the latter method proving itself, by means of specialized application and method, to be the most suitable for the very exacting performance demanded. The introduction and improvement of electronics is now playing an increasing part in the operation of railways, and holds much promise for greater application in the future, taking under its wing not only control and peripheral installations as they are known today, but also new capabilities in the form of revenue collection, data handling, and streamlined administration. The recent trend is toward automation, to which railway systems are particularly adaptable, but there are still many unsolved problems. In signaling and conununications, managements have not only the best possible insurance policy, but an indispensable tool for commercial viability; these two assets will play a large and vital role in the imminent transport explosion of the future.