Train signal

“ The signal must be returned to red as soon as a train has passed. It must only be fastened at white when no operator is on duty. This signal must also display red to hold trains running in the same direction the required time apart. Operators must be prepared with other signals to use promptly if the fixed signal « 91 » should fail to work properly. If a signal is not displayed at a night office, trains which have not been previously notified must stop and inquire the cause, and report the facts to the superintendent from the next open telegraph office. ”

“ The enormous train service on some of these first-rank lines demands the highest efficiency in the signalling and interlocking arrangements, and the use of any devices which will ensure increased facility and safety in the working of the traffic. With a crowd of trains passing a signal-cabin in both directions, and often over four lines of way, it is quite possible for a signalman to make a mistake which cannot be rectified in time to prevent an accident. ”

“ That is to say, if the despatcher desires to make a meeting point for two trains, he will send the same order simultaneously to both of them. If a train is leaving his end of the division and he desires to make a meeting point with a train coming in, before giving his order to his conductor and engineer, he would telegraph it to a station at which the incoming train was soon to arrive, and from whence the operator would repeat it back word for word, and would give a signal signifying that his red board was turned. ”

“ The position of the signal arms or blades in the daylight, and the colours shown by the lamps at night, form the code of signals for the proper working of the train service; and as the signal arms and lamps are both worked simultaneously by the same gearing, it [Pg 314] is only necessary to light the lamps to put the signals in complete condition for night-working. For some years, when the traffic was small, with trains at low speeds and at considerable intervals, one double-arm semaphore signal-post at a station was made to serve for all purposes ”

“ Whenever a Train is stopped at any intermediate Station, or on the Line, it is the special duty of the Breaksman to see that the contents of the waggons are not interfered with, and that the proper Signals are given when the Line is obstructed. In case of a break-down or other stoppage on the main Line, he is to go back 600 yards, or until he meet a Policeman, making the proper signal with a Red Flag by day, or Red Lamp by night, or in foggy weather by placing a Fog Signal on the Rail to stop any approaching Train, leaving the waggons in the charge of the Engineman ”

“ 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! ”

“ One train isn’t allowed into a block as long as there’s another train in it. In this signal box you see they have small hand levers to control the points and signals, which are power operated.
Britain has the safest railways in the world largely because of good signalling equipment, complete fencing of the track, raised platforms at all stations and close and detailed examinations of rolling stock and locomotives. And what we call block working is the very basis of our signalling system. No train can be signalled into the block section while there’s another train in it. ”

“ 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. ”

“ In more recent years the weight of opinion has been that in all systems of danger signals the normal position, and that to which such signals should automatically move, is that indicating danger. So arranged, the indicator will always be in a position to stop trains unless it is moved to another position to show that there are no orders for them. It becomes a standing order to "hold," and, when an order is forwarded for a train, the fact of its receipt requires that the signal be simply left in its normal position and the train thus stopped. ”

“ 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. ”

“ This seems a good provision, as such train has no right to proceed even as an extra, and under many circumstances the Dispatcher would have difficulty in getting control of a train without this help. The discussion of this belongs, however, more properly with the consideration of train rules.
Rule 524 (A) —A fixed signal must be used at each train-order office, which shall display red at all times when there is an operator on duty, except when changed to white to allow a train to pass after getting orders, or for which there are no orders. ”

“ Automatic signals are sometimes made to stand normally (when no train is in the section) in the " stop " position. The local circuit is connected with the rail circuit so that it is closed only when a train is approaching within, say, 1 m. With the rail circuit, distant signals are controlled, without a line wire, by means of a polarized relay. Each signal, when cleared, changes the polarity of the rail circuit for the next section in its rear, and inis, by the polarized relay, closes the local circuit of the distant signal, without affecting the home signal for that section. ”

“ 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. ”

“ A goods train consisting of between twenty and thirty waggons is often started from stations under the charge of one guard. The night may be dull and foggy, and the train may have to stop at several stations to put off and take on trucks. At some small stations the guard has everything to attend to himself, having to detach, hook on, and give signals to the engine-driver. ”

“ The second important function of a railroad signal—second only to its all-important one of safety to human life and to property—is to keep trains moving. It is a poor business man indeed who does not recognize the high value of keeping all of his moving equipment as nearly as possible in constant motion and in this way holding down the cost of his overhead.
There are two ways to direct the movement of trains. The first is the one still most commonly in use upon the railroad of the United States, by the written instructions of the train-order ”

“ A combined green and white signal, for instance, is used to stop a train at a flag station; and a blue flag by day, or a blue light by night, displayed at one or both ends of an engine, car, or train, indicates that workmen are under or about it. When thus protected, it must not be coupled to or moved, and no man may remove these signals but the one who placed them there. This rule is enforced absolutely to safeguard, as far as possible, the lives of the employees of the road. ”

“ 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. ”

“ That the automatic electric signal system is complicated, and in many of its [176] parts of most delicate construction, is undeniable. So also is the locomotive. In point of fact the whole railroad organization from beginning to end—from machine-shop to train-movement—is at once so vast and complicated, so delicate in that action which goes on with such velocity and power, that it is small cause for wonder that in the beginning all plain, sensible, practical men scouted it as the fanciful creation of visionaries. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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? ”

“ Collisions, our broker quickly perceives, are impossible, there being no switches, and notwithstanding the multitude of passengers (some{43} twenty thousand per day) there are never more than two cars on the line at a time, and there are no stoppages between the two termini.
For signalling purposes, the line is divided into four sections of about five miles each, and as the train passes by, its electric motor automatically operates the signal and immediately “blocks” the section behind it, so that the train following cannot advance until its leader has cleared the five-mile division. ”

“ The thin end of a pair of facing points can be jerked far enough open, while a train is passing over at great speed, for the wheels of any carriage to strike them on the reverse side, as soon as the wheels of the previous carriage have travelled about two-thirds the length of the points. Thus it will be seen, that in any of the above-named distances between the wheels upon a vehicle, or between the wheels of one vehicle and those of that following it, if the signals are placed at “danger” before the whole train has passed, the facing points can be jerked open. ”

“ When the apparatus is properly constructed and efficiently maintained, the signalman cannot make a mistake in the working of his points and signals which shall lead to accident or collision, except only by first lowering his signal and switching his train forward, then putting up his signal again as it approaches, and altering the points as the driver comes up to, or while he is passing over them. ”

“ A succession of short blasts means danger ahead—and is used, too, to scare cows and horses off the track.
There is yet another class of signals, which are given with the signal-cord which runs overhead through every passenger-coach. Every one, of course, has seen this cord, and has also seen the conductor use it to signal to the engineer. It is connected with a little valve over the door of the car, and every time the conductor pulls it, there is a little hiss from the valve as of escaping steam. ”

“ 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. ”