Railway signal

“ The distant signal is placed at varying distances behind the home signal according to the gradient of the line and other circumstances, but on a straight and level railway it would be about 1,000 yards back, and its function is to repeat the action of the home signal, so that if the latter is at danger the driver has timely intimation of the fact, and can at once reduce the speed of his train so as to stop at the home signal. ”

“ The railway is watched by foremen, with “gangs” of men under them, in lengths varying from twelve to five miles, according to circumstances. Their continuous duty is to see that the rails and chairs are sound, their fastenings complete, and the line clear of all obstructions.
Then, at all the junctions, sidings, and crossings, pointsmen are stationed, with definite instructions as to the duties to be performed by them. At these places, signals are provided, worked from the station platforms, or from special signal boxes, for the purpose of protecting the stopping or passing trains. ”

“ By this invention, simple in itself, the foundation was obtained for the development of practically every one of the intricate systems of railway block signaling in use today wherein the train is, under all conditions, continuously active in maintaining its own protection.
"In other words the track circuit is today the only medium recognized as fundamentally safe by experts in railway signaling whereby a train or any part thereof may retain continuous and direct control of a block signal while occupying any portion of the track guarded by the signal." ”

“ Since the inception of the Institution of Railway Signal Engineers a great amount of work has been done in discussing and studying requisites and so on for track circuit work, both of the direct current and alternating current types. All this has resulted in increased confidence on the part of the traffic officers in track circuit and allied apparatus and caused them to look more and more to the signal engineer to help them in their work and to accord him the respect and credit he deserves. ”

“ Where the traffic is moderate, it may be sufficient to have block-telegraph instruments at each of the stations, but with a very frequent train service it will be found necessary to divide the line into shorter sections, and erect signal-cabins and block-telegraph instruments at intermediate points between stations. ”

“ Thus, the automatic signal system of the Union Switch and Signal Co. consists, in every essential particular, of the Robinson system, pure and simple.
It may be here pointed out that all the railway signal companies now in operation, installing automatic signals under whatever name, are using the Robinson system bodily, and have been since the expiration of Robinson's basic patents. There is no other system, as a system, in use. ”

“ Moreover, while a train is actually travelling through the points, it is itself master of the situation; not even the signalman can, either intentionally or inadvertently, change their position or disturb them until the whole train is safely passed. When he gives a clear signal for a main line, he cannot open a point crossing to it; when he gives a clear signal for a crossing he must show danger for all the lines which it crosses. And this is the meaning of the numbers marked on the different levers. ”

“ For this reason fast time on a railroad depends as much on having a good signal system to assure the locomotive-runners that the line is clear, as it does on the locomotives. If he is always liable to encounter, and must be on the look-out for, obstructions at frequent grade-crossings of common roads, or if he is not certain whether the train in front of him is out of his way or not, the locomotive-runner will be nervous and be almost sure to lose time. ”

“ He shows that, notwithstanding the important part played by signals in the working of railways, the signalman is frequently very imperfectly instructed in their use. This official has often to learn his duties as best he can from his predecessor. He goes through a theoretical examination at the office of the Superintendent of the Line, it is true, but this does not in any way test his practical ability to perform the duties. Such a practice must necessarily be fraught with the greatest danger to railway passengers. ”

“ This Inquiry System, which I shall presently explain, has its bearings upon a certain class of Railway Accidents, and mostly concerns engine-drivers, guards, signalmen, and foremen porters. At busy junctions it often happens that there are three or four trains, from different branches or directions, all signalled at once, and wanting to cross over the junction at the same time. It is simply impossible for the signalman to get all these trains across, and past, without detention to some of them ”

“ With a modern interlocking frame, and assuming the normal position of all the signals to be at danger, then before a signal can be lowered for an approaching engine or train all the switches and corresponding signals, from any lines or sidings connecting with the line to be signalled clear must first be set so as to prevent any engine or train coming out of such connecting lines or switches on to the line to be made clear. ”

“ Distant-signals to be distinguished by notches cut out of the ends of the arms, and to be controlled by home or starting signals for the same direction when on the same post. A distant-signal arm must not be placed above a home or starting signal arm on the same post for trains going in the same direction. ”

“ Just consider for a minute the position of an engine-driver with an express train, timed to run at fifty miles an hour without stopping! how many distant signals he has to pass in that distance which he never catches the least glimpse of whatever! and how many times he has to trust to chance, sooner than lose time! ”

“ As an additional precaution, should no flag be handy, it warns drivers that “anything moved violently up and down or a man holding both hands up is a sign of danger.”
Some of these early regulations were extremely primitive. For instance, long before the scientific system of the block telegraph and the tablet were thought out, it was deemed sufficient to ordain that “On a Train or Engine stopping at or passing an intermediate station or Junction, a STOP Signal must be exhibited for FIVE minutes, after which a CAUTION Signal must be exhibited for FIVE minutes more.” ”

“ It often occurs if this system is not in use, where there is a space of six or seven miles between stations, that there are two or three trains following one another at short intervals upon the same line of rails; and, under these circumstances, there is great danger of one train overtaking the other. ”

“ By its means the trains are started from the stations and conducted safely from point to point throughout their journey; the signalmen who regulate their passage are placed in an unbroken chain of communication one with the other; the nature of the train and its destination, and the fact of its punctual running, or otherwise, are flashed ahead from signal cabin to signal cabin as it speeds on its journey; while the faithful telegraph warns the signalman if his signals are not acting freely or if his lamps are not burning brightly. ”

“ And in the approaches to some of our great depots, where trains and tracks are multiplied and confused with cross-overs and switching service, all switches are set and all movements controlled by signals from a single central tower. Sometimes, by very expensive and complicated apparatus, it is made mechanically impossible to open a track for the movement of a train without previously locking all openings by which another train might interfere. The illustrations on pages 169, 171, and above will serve to give some general idea of these appliances. [17]
Central Switch and Signal Tower. ”

“ Where flames had been there were now streamers of smoke; but the countless ruins of shattered and gutted houses and blasted and blackened trees that the night had hidden stood out now gaunt and terrible in the pitiless light of dawn. Yet here and there some object had had the luck to escape—a white railway signal here, the end of a greenhouse there, white and fresh amid the wreckage. Never before in the history of warfare had destruction been so indiscriminate and so universal. ”

“ When a misunderstanding arises (such as I have described) , the signalman has to trust entirely to memory, whereas the man in the open country, who can see from one station to another, can tell when a train is clear of the station in advance, or can see a train coming, that he might be otherwise in doubt about. This should be taken into consideration by railway authorities when mistakes occur, for, depend upon it, there is nothing gained by being too severe with good and trustworthy servants. ”

“ No station to be constructed, and no siding to join a passenger line, on a steeper gradient than 1 in 260, except where it is unavoidable. When the line is double, and the gradient at a station or siding-junction is necessarily steeper than 1 in 260, and when danger is to be apprehended from vehicles running back, a catch-siding with points weighted for the siding, or a throw-off switch, to be provided to intercept runaway vehicles at a distance outside the home-signal for the ascending line, greater than the length of the longest train running upon the line. ”

“ Directly a fog comes on, a man is stationed at the foot of each distant signal, and becomes, in fact, a living signal-post. As soon as the signal-arm is raised to "Danger," he places upon the rails two detonating signals, which are exploded by the engine of a train passing over them, and the driver of the train is thus apprised that the signal, although invisible to him, is at "Danger," and he must act accordingly. ”

“ The history of railway signals is a curious page in the annals of practical science. For some years signals seem scarcely to have been dreamt of. Holding up a hat or an umbrella was at first sufficient to stop a train at an intermediate station. At level crossings the gates had to stand closed across the line of rails, and on the top bar hung a lamp to indicate to drivers that the way was blocked. In 1839, Colonel Landman, of the Croydon line, said that he should avoid the danger at a junction during a fog by going slowly, tolling a bell, beating a drum, or sounding a whistle. ”

“ Imagine one of our gigantic locomotives having its opposite drivers electrically insulated from one another!
Figure 18 represents the signal system described in William Bull's English patent of October 31, 1860. In this system, it will be observed, the rail sections used are short, "twenty feet, more or less," and are the terminals of line wires which connect with the battery and magnet at the station. The signal at the station is visual and consists of an indicator operated by wheel work actuated or controlled by the electro-magnet M shown in the diagram. ”

“ If a train, arriving at the signal-box, has to call at the siding, the breakman, or person in charge, intimates the fact to the signalman, who, by the insertion of an ordinary carriage key into the electrical apparatus, disconnects the wire. ”

“ And yet an honest man of that type is the kind demanded for such a place. The interlocking of switches and signals (the arrangement in a frame of the levers moving the switches and those moving signals in such a way that the signal which tells the engineer to come on cannot be given until the switch is actually in proper position) is one of the notable improvements of the last twenty years, and is a great boon to switchmen, as well as to passengers and the owners of railroads. ”

“ A siding may be a hundred or a hundred and fifty yards from the signal-box. On a dark, and perhaps foggy night, the usual way of performing shunting at the present time is, for the signalman to depend upon the man in charge to show him a white light by hand lamp, or give a signal on a gong worked by electricity, when the main line is all clear for another train to pass. Now the former is a very dangerous system, for where shunting is taking place, the guards and the men in charge have each lights in their hands; there are also lights on the engine, and on the train which is being shunted. ”

“ In some cases much assistance has been obtained by shortening the lengths of the working sections and introducing intermediate electric telegraph block stations between the ordinary stations. Long refuge-sidings have also been introduced at many of the signal-cabins or stations, into which goods trains can be shunted out of the way to allow fast passenger trains to pass through without stopping. ”

“ Suppose a train moving along the track, A, A, from left to right in a direction indicated by the arrow. Upon reaching the point, a, the wheels and axles of the train will form an electrical connection between the opposite insulated rails, and a circuit will be formed between the conductor, C, and the conductor, Z, traversing wires, 1 and 2, magnet, M, and wire, 3, and the signal attached to M will consequently be displayed. ”

“ Accidents are often caused through engine-drivers being unable to see distant signals in foggy weather. Some of these signals are as much as forty feet high, or even more. How are they to be any guide to the engine-driver when he can hardly see three feet above his head? He might as well look for the “man in the moon,” as try to get the faintest glimpse of a distant signal under such circumstances. What is he to do? Is he to pull his train up and wait while his fireman or the guard goes back and climbs the signal-post to ascertain how the signal is standing? ”