American Railway Association

“ The increased price of wages and materials has hampered progress a great deal and it will be some time yet before any great improvement is noticeable. On the other hand, the great increase in wages has caused a demand on the railways for a reduction of operating costs with the result that signal engineers are endeavoring to produce schemes which will enable signal towers to be abolished or closed at intervals where they were formerly kept continuously in service and in this and other ways to dispense with unnecessary staff. It is in this that the track circuit will help very considerably. ”

“ Single rail track circuits, so called from the fact that but one rail is insulated, are also used. Installations of this kind are made to avoid the expense of two insulated joints or where one rail is needed for another circuit. Such track circuits are more liable to failure than those having both rails insulated for the reason that the break-down of one insulated joint will extend the circuit beyond the proper limit and cause interference of neighboring circuits or extended shunting of the relay, due to the presence of a train beyond the insulated joint. ”

“ The Robinson automatic system is admittedly the only signal system ever produced that meets all the requirements of safe and rapid railroading. Robinson's subsidiary invention of the rail bond, made more than fifty years ago in connection with his automatic system of signaling, and now in universal use on all electric roads using the track return, throughout the world, has made possible electric railroading as practiced today. ”

“ The English light weight four-wheeled freight car without air brakes was and still is a bother to the track circuit engineer because of the difficulty of getting a satisfactorily low shunt under all circumstances. Then again the Mansell disc wheel made it necessary to resort to bonding between the tire and the hub before a vehicle would shunt the track circuit at all and this was an expense to which the companies were loath to go, especially if they had or contemplated very few track circuits, though the use of even one circuit really necessitated the whole of these wheels being so treated. ”

“ Before describing the operation of the apparatus as a whole, it may be stated that the electric current will follow a naked metallic conductor if of sufficient surface, even when immersed in a river or in the mud at the bottom of a river, because the metal offers less resistance to its passage than either water or mud. Much more will it follow the rails of a railroad track when they are made a part of the circuit, since the rails present a large surface of good conducting material, which offers much less resistance to its passage than any surrounding mediums ”

“ When a train enters upon a section or block it prevents the section back of it from receiving working current. Thus any number of trains following each other will each be deprived of working current when the length of a block back of the train ahead of it, whether that train be running or standing still, thus preventing collisions. A train approaching a switch or drawbridge is automatically arrested the length of a block away from the block containing the switch or draw before a bolt can be withdrawn or a lock released in the latter. ”

“ Until recently it has been the general opinion of all experts on the track circuit that the rail resistance was rather an unimportant factor and that, as a general rule, the change in rail resistance could be disregarded in making track circuit investigations and calculations.
Many bad track circuit conditions have been laid to bad ballast conditions, zinc treated ties, wet track, etc., which, if carefully analyzed, would have shown the trouble to be due to extremely high rail resistance. These faulty conclusions are being drawn nearly every day. ”

“ 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. ”

“ Cinders, dirty sand, soft water-logged ties and ballast not well cleaned away from the base of the rail will produce track circuit trouble, particularly during wet weather, while good rock ballast, sound ties and clean track give the greatest efficiency.
The use of ties freshly treated with zinc chloride also reduces the ballast resistance. If too many such ties are used in a track circuit the current leakage between rails becomes so great that not enough current reaches the relay to hold it closed, the effect being the same as if a train is on the track circuit shunting out the relay. ”

“ 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. ”

“ It has practically a negligible internal resistance and it is also necessary to use an external resistance in the leads between the cell and the track to prevent a flow of excessive current when a train occupies the track. The dry cell is used only in emergency cases or occasionally for open circuit track circuits of 2 or 3 rail lengths, which are sometimes used as annunciator starts to announce the approach of a train to a tower-man. It is designed primarily for open circuit work and will polarize when current beyond a certain figure is drawn continuously from it. ”

“ It is not infrequent to find the rail resistance to be as high as 0.20 ohms per 1,000 ft. of track, and we have known it to run as high as 0.264 in new rail, where especial attention had been given to obtaining as good bonding as possible. Under such conditions the angle bar carries very little of the current, the capacity of the bond is not sufficient to carry the current, and the net result is a failing track circuit, which is probably attributed to bad ballast, zinc treated ties or other causes. ”

“ Where switches occur in a track circuit, special means must be employed to prevent short-circuiting through the switch rods and leakage of current to the turn-out rail. The usual method is the use of insulated switch rods with insulated joints in the leads of the turnout and at the fouling point of the turnout. The switch points are bonded to the stock rails to insure shunting by a pair of wheels on any part of the track. ”

“ Dry rust forming between the fish plates and the rails of the track, at the joints, makes a poor conductor, and hence the low current, from only one or two cells of battery used in the rail circuit for signaling is very liable to find sufficient resistance at the joints from this cause to prevent the continuous passage of the current through the rails to the relay. ”

“ The usual form of track circuit has a primary battery at one end of the insulated track section, with the positive terminal of the battery connected to one rail and the negative terminal to the other, while a relay at the other end of the section is connected to the rails in a similar manner. Current flows from the positive side of the battery through the one rail, the relay and the other rail back to the battery, thus keeping the relay energized. ”

“ A track circuit may be made to perform two separate functions in which the direction or polarity as well as the presence of current is made use of in the relay, provided the first or principal function actuated by the presence or absence of current does not interfere with the secondary function, actuated both by the presence of current and its polarity. ”

“ Some of the common track circuit ailments are relay and track battery troubles, defective track connections, poor bonding and broken rails, short circuits or shunts, excessive leakage and defective insulated joints, all of which will cause the signals to be set in the danger position, while defective relays, foreign current and poor wheel contact may result in a false proceed signal indication with a train in the block section. ”

“ A greater number of jars is never advisable since by increasing the intensity of the current, the liability of its leaking from one rail to the other during wet weather is correspondingly increased, and as this is attended with some uncertainty in the working of the relay of the section—due to the varying intensity of the current—it should be carefully guarded against. ”

“ In this connection I may mention the well known Robinson Radial Car Truck, which is in quite extensive operation on electric railways. This is the only car truck, I believe, ever designed and constructed on correct mechanical principles. It is so constructed that every axle in the car or train becomes exactly radial to any curve around which it passes, all the axles becoming parallel on straight lines only. This prevents wear and tear and grinding and derailment on curves. It also greatly economizes current. ”

“ The batteries for operating the signals will last for months without attention, and one man can readily attend to all the signals and batteries throughout the whole extent of a road.
In all cases, where practicable, the signal wire should be carried through the coils of a bell-magnet in the nearest office. By this means the operator is informed when the battery power is decreasing, and warned that it requires renewing. ”

“ He who would discover truth must not accept anything because it is popularly accepted, or reject anything because it is popularly rejected; nor must he regard anything as impossible because never heretofore accomplished, although perhaps attempted by the most able scientists. ”

“ The invention consists in an improved signal of very simple construction, by which great ease of action is secured. It also embraces certain peculiarities in the arrangement of wires from the signal and battery to the track. A in the drawing represents a double-track railroad. C is a section of track, which may be a mile long, more or less, and having its rails a b separated from metallic contact with the rails of the sections D and E, as shown at a' b'. In like manner the section C' of the other track has its rails separated from metallic contact with the rails of the sections D' and E'. ”

“ The design of the invention is to communicate between trains on the same line, and between trains and stations, for which purpose it is proposed to use long sections of rails. The unpractical part of this system is that to make it operate it is necessary, as the inventors say, to insulate the opposite wheels of all the carriages from each other, in order that electrical connection may not be established between the opposite rail line by the wheels and axle. ”

“ If a switch or draw-bridge is misplaced an approaching train will set an alarm ringing at the station and will also exhibit a red signal ahead of the train as a warning to the engineer that the switch is misplaced. ”

“ They all have, however, track circuits installed at various places in connection with the ordinary signaling. Owing to the lower standard of living and the employment of women operators at many points, there is not so great an incentive to the adoption of automatic devices, as in some other countries. French engineers, however, know what Americans have done in this way and some very complete accounts of American systems have appeared in "La Revue generale des chemins de fer." The Paris Metropolitan line is automatically signaled by an intermittent contact system without track circuit. ”

“ The reason for the above is obvious: that there should be no room left between the bond and rail for rust to form. It follows then that a bond held in position by an independent plug which renders it necessary for the current to pass from the bond to the intermediate plug and from that plug to the rail, is not the best form of bond, for the reason that it presents a double surface on which rust may form. ”

“ A train when it leaves a station, and at various points as it passes, indicates to the stations along the line, its Location, Direction, Rapidity, and Length. Thus all necessary information regarding moving trains is automatically announced every few minutes at the stations. ”

“ The third rail or contact conductor is made in sections or blocks of any desired length, which sections are normally dead but become automatically alive when a train enters thereupon, and dead when the train leaves the section. ”

“ Robinson's automatic signal system has increased the traffic capacity of the New York subway at least three-fold, and probably twice that. Without it the subway equipment could not transport with safety, one-fourth the number of passengers now carried. This invention has created a practically new industry, giving employment to many thousands of men, in various capacities, skilled and unskilled. ”

“ The Emperor and several members of his suit took passage on board a special train on the Lowell railroad soon after 8 o'clock yesterday morning and arrived at the West Somerville station about 8:30, where they were met by Professor Robinson, who at once began to explain to the royal party his system. At Elm street a large visual signal is placed which is controlled by the current from a single cell of a battery connected with the rail sections at North avenue, no line wires whatever being used. ”

“ As two jars of gravity battery are not sufficient to operate a signal, lock, bell or any similar instrument with any degree of certainty, it becomes necessary to have a second set of batteries of a greater number of jars for that purpose. ”

“ The system is elaborate, providing for safety on and off the trains, economy of current, simplicity and certainty in action, dispenses largely with electrolytic action, and when alternating propulsion current is used the return is confined to the length of the block. It is believed that the system will prevent all danger to passengers and trains from the direct action of the propulsion current. ”

“ The same remarks apply generally to Austria, Holland and Scandinavia, though in the latter case English ideas are more in evidence and it is probable that the track circuit, already in use to some extent, will be developed as time goes on. In Austria automatic signaling was certainly tried on a small scale on the Southern Railway, but with what results the writer cannot say. In Switzerland the extended use of iron ties is against the track circuit. ”