Signal (transport)

“ Regulation 44 (2) requires that the height of the centre of each light signal from the surface of the carriageway in the immediate vicinity shall be not less than 5.5m nor more than 9 m. Each signal is prescribed with maximum and minimum dimensions. ”

“ Both signs should be internally illuminated at all times. (At present the Turn Left (or Right) sign is only illuminated when the green signal is illuminated, but is legible at all times during daylight.)
(b) The signs should be placed beside the green lens, and on that side of the signal head appropriate to the wording on the sign (e.g. “Turn Left” on the left side of the signal and “No Right Turn” on the right side of the signal) provided that this can be done without rendering inadequate the clearance between the signals and traffic on the carriageway. ”

“ Traffic light signals designed primarily for controlling the movement of vehicular traffic also contribute to the safety of the pedestrian in providing opportunities for crossing the carriageway when vehicular traffic is held up. In designing traffic light signal installations the needs of pedestrian traffic should be fully considered and such provision for that traffic as is practicable should be made. ”

“ As soon as possible after a fog comes on, a man is stationed at the foot of each distant signal, and generally of each home signal also, who by means of detonators, red and green flags and a hand-lamp, conveys information to the driver of every train as to the position of the semaphore arm. ”

“ 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. ”

“ 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. ”

“ 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? ”

“ TRAFFIC SIGNAL STOP LINE
3.7 The marking (diagram 1001) consists of a single continuous line 200 mm or 300 mm in width and indicates the position beyond which a driver must not proceed when required to stop by light signals. The 200 mm width is generally for use in urban areas. The 300 mm width should be used in rural areas, or where the 85th percentile speed exceeds 35 mph. The greater width may also be used in urban areas at difficult locations, or where heavy traffic results in rapid erosion of the marking. ”

“ Pedestrians and Light Signals—Methods for making provision for pedestrian traffic at signal installations are indicated, and the experimental provision of a series of pedestrian signals controlling vehicular traffic on a flexible progressive system is recommended. ”

“ 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. ”

“ 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. ”

“ They direct by signs, which are quite as intelligible as words, the drivers of the trains starting from inside the station, as well as those of the trains arriving from outside. By pulling a lever-handle, a distant signal, perhaps out of sight, is set some hundred yards off, which the approaching driver—reading it quickly as he comes along—at once interprets, and stops or advances as the signal may direct. ”

“ To avoid an accident taking place from the failure of either rodding or gearing, the signal-detector has been devised, so as to prevent the possibility of pulling over the signal wire until the points and locking-bar are both in their proper positions. ”

“ 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. ”

“ The signal and telegraph stations are fifty miles apart, sometimes more. In these long runs the motorman stops only when a signal is turned against him or if by accident he discerns a train in the Tube ahead of him. ”

“ In fact, the first rule under the “Use of Signals” is that a signal imperfectly displayed, or the absence of a signal from a place where one is usually shown, must be regarded as a stop signal.
The railroads are trying all the time to find some « 77 » third colour which can be used satisfactorily in signalling. Red for danger and green for safety are very well, as far as they go; but a caution signal is badly needed—one which will not absolutely stop a train, but which will warn the engineer to get it under control and proceed carefully. ”

“ You know the signals along the line of the railroad—those gaunt, uncanny things that spell danger or safety to the men in the engine-cabs. A little while ago, we stood beside a man in the sun-filled tower of a great railroad terminal and watched him operate the most complicated switch and signal system in the land, watched him with the crooking of a finger upon the lever of an electric machine raise this blade, lower that, as he made new paths for the many trains, coming and going. ”

“ For instance, when a pointsman is letting a train in or out of a siding by hand signal upon the ground, or attending to main line points, during shunting, he is generally upon the spot, and has, of course, the points close under his eye, so that he can at once see whether they are properly closed or not. ”

“ 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. ”

“ On all railroads there are certain fixed signals for the guidance and information of employees. When caution is called for, the light is usually green and the semaphore horizontal. Now, as the writer looks at it, when any signal indicates caution, it is not to be looked upon as a permissive or conditional signal to be interpreted at will by different enginemen. According to the rules and to common sense when a train, at the time a cautionary signal is sighted, is running thirty or forty miles an hour, it calls for a positive and not a theoretical reduction in speed. ”

“ 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. ”

“ 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. ”

“ When the electric bell is silent there is no train within half a mile and the crossing is safe; it is not safe while the bell is ringing. As it now stands the law usually provides that the prescribed signals, either bell or whistle, shall be given from the locomotive as it approaches the highway, and at a fixed distance from it. The signal, therefore, is given at a distance of several hundred yards, more or less, from the point of danger. ”

“ 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! ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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 engineer who « 78 » fails to run on time, either through timidity or overcaution, is very soon relegated to the work-train or the yard-engine—a humiliating fall for the master of the queenly flyer.
As Byers was a junction, there were two signals there for the government of trains, one a train-signal on the front of the shanty, and the other a semaphore just outside the door. The train-signal was merely an arm or signal-blade, operated by a lever inside the shanty. ”

“ 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. ”

“ Safety appliances for railways have been of growing importance in proportion to the increase of the weight and speed of trains; at the same time, very few of these appliances are used solely with a view to safety, most of them having some mechanical function to fulfill apart from the promotion of safety. Signals are one of the most important items of this class, and serve to keep the trains a certain distance apart, as well as to inform the engine runners of the condition of the tracks at switches, crossings, etc. The semaphore is the standard signal in both the United States and England. ”

“ The only things in sight were a water-tank, a pump-house and the telegraph office; and I wish you could have seen that office. It was simply the bed of a box-car, taken off the trucks and set down with one end towards the track. A small platform, two windows, a door, and the signal board perched high on a pole completed the outfit.
I arrived at six-thirty in the morning and there wasn't a living soul in sight. An hour later, a big broad shouldered Irishman who proved to be the pumper, came ambling along on a railroad velocipede. ”