CONTENTS. PAGE CHAPTER I. Block Signaling What it is for, What it does, How it does it - - i CHAPTER II. Methods of Operation and Rules 17 CHAPTER III. Construction The Telegraphic Systems CHAPTER IV. Construction The Controlled Manual Systems . ... 51 CHAPTER V. Construction The Automatic Electric Systems CHAPTER VI. Construction The Automatic Electric Systems, continued 83 CHAPTER VII. Construction The Automatic Mechanical and the Staff Systems CHAPTER VIII. Installation and Care of Automatic Electric Signals, with a Comparison of the Cost of the Different Block Signal Systems 123 CHAPTER IX. What They are For andHow They are Operated .... 143 CHAPTER X. For Junction Points and Drawbridges Construction of the Improved Saxby Farmer Interlocking Machine 165 CHAPTER XI. The Stevens Machine, and How a Switch is Moved and Locked 183 CHAPTER XII. Details of Construction 199 CHAPTER XIII. The Westinghouse Electro-Pneumatic and the Gibbs Electric Street Railway Systems CHAPTER XIV. Agreements, Contracts, Specifications, Installation and Repairs CHAPTER XV. Switch Signals 257 33 65 101 220 241 OF THK UNIVERSITY BLOCK SIGNALING. WHAT IT IS FOR. WHAT IT DOES. HOW IT DOES IT. By W. H. ELLIOTT, SIGNAL ENGINEER, C., M. ST. P. R.R. CHAPTER L What are we stopping for, conductor, out here in the woods This is a limited train. What stopped by a signal, a block signal, you say Why, what is that Oh, I see You have a red blade projecting from the top of a pole to indicate to the engineer when the blade is moved up or down whether he may enter the block or not, the block being the piece of track extending to the next signal. So, then, when we are stopped by such a signal it means that another train is in the block, and we will have to wait until it has passed out. And thus it is that to-day trains are being run through towns and cities, over mountains and prairie, through bridges and tun- nels, in cuts and around curves with absolute safety, a fact not fully appreciated by the traveling public, but which becomes to the engineer, whose responsibility is lightened and from whom anxiety is removed, a guiding star, telling him that the track is his and that there will be no one to dispute it with him, for such little arguments, you know, are sometimes disastrous. Block signaling, though limited in extent in this country, in proportion to the miles of track operated, is so rapidly being ex- tended, not only from the natural increase of business and conse- quent demands for a safe method of operation, but from the general knowl- edge being acquired of the advantages to be gained from such a system, that I believe an article on the subjectwould be both interesting and instructive. To the man well posted on signal matters, little that isnew will be found, as this article is written more for those who are constantly guided by a signal, but have little idea of its construction. The commencement of signaling may be said to begin with the use of the locomotive, for it soon became manifest that some- thing would have to be de- vised, not only to prevent collisions between trains, but to give information to engineers regarding the position of switches and the right to go ahead. Many forms and devices were used in these early days, few of them being seen to-day, but which, as in the development of the locomotive, became stepping stones to things much better. As each engineer pre- 1. Home BlockSignal-All Clear. 2. Home Block Signal Danger, Stop. 3. Distant Signal 4 Home Block Signal- All Clear. 1 Danger. ferred his own devices to those of others, it followed, as a matter of course, that the practice was very varied, so much so in some cases that the safety signal on one road became the danger signal of another...