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Ill THE SIGNAL DICTIONARY PREFACE TO THE FIRST EDITION Railway signaling is a comparatively new art, and a )idly growing one, so that its nomenclature is unsettled and its practices varied; and numerous changes of a somewhat radical nature are still going on. The development of scientific signaling, as distinguished from the earlier and empirical methods...
Ill THE SIGNAL DICTIONARY PREFACE TO THE FIRST EDITION Railway signaling is a comparatively new art, and a )idly growing one, so that its nomenclature is unsettled and its practices varied; and numerous changes of a somewhat radical nature are still going on. The development of scientific signaling, as distinguished from the earlier and empirical methods of controlling the movements of railway trains, has proceeded from a curious combination of motives; in some cases, from the enterprise of trained men, in others from a pressing necessity due to expansion of business, and in still others to the force of public opinion, both the public and the railway officer being sometimes actuated by injudicious haste. That w-e are not yet out of the transition state is no cause for surprise. In making a signaling dictionary the very first step calls for arbitrary action. Hand-motion signaling, with or without the use of flags and lanterns, is excluded, because those features have no need of the services of the signal engineer. A slow-board is a fixed signal, but the signal engineer scarcely gives it a thought. On the other hand, automatic bells at highway crossings logically do not come under the head of railway signals, for they do not directly affect the movement of trains; but the signal engineer does take cognizance of this class, because it requires skilled attention and is usually put in his charge. In fixed signals, which constitute the subject of this work, American railway officers often make a distinction which is wholly arbitrary and, in most cases, useless that between interlocking signals and block signals. The function of a signal being clearly stated, the English nomenclature, ignoring this distinction, is entirely adequate. But to make each collection of drawings complete in itself, we recognize this distinction; and the reader will find under the two diff(Typographical errors above are due to OCR software and don't occur in the book.)
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