US2038635A - Apparatus for railway train signaling systems - Google Patents

Description

pfi'ii 28, 193. p N ss I ZDEfig APPARATUS FOR RAILWAY TRAIN SIGNALING SYSTEMS Filed Aug. 22, 1954 S C2 C3 F1 Fill?! 'HA TA T4 Paul N.

F @915, HIS ATTORNEY Patented Apr. 28, 1936 UNIFTEYD' STATES PATENT o-FFIcE ADPIiC-atiOn'AuglISt-ZZ, 1934 Serial'No. 740,929

11 claims.

My inventionrelates to apparatus forrailway trainsignaling systems, and particula-rly for railway train signaling systems which utilize the traffic rails as part of a communication cir- 5 cuit.

I will describe severalforms of apparatus embodying my invention and' will then-point out the-novel features-thereof in claims.

A' feature of myinvention is the provisionin systems of the type here involved- 0fmore efiicient and improvedtrain-carried inductors. A further feature of my invention is the provision in such systemsof receiving'inductors immune toforeign space magnetic'fields, together with 15 inductors efficient for sending-the latter being connected with the receiving inductors and-all of them used for sending. Another feature or my invention is the provision of apparatus wherein two or more inductors at points on the 20 equipped vehicle spaced apart are combined for sending. and receiving'and not only a large power transfer obtained but loss of signal at insulated rail joints is avoided:

For a better understanding of my invention 25 reference may be had to the accompanying drawing in which Fig. 1 is a View partly diagrammatic and partly perspective of one form of .multiple inductors embodying my invention. Fig." 2 is a diagrammatic view showing a modified arrangement for combining the multiple inductors of Fig; 1; Fig. 3 isa view partly diagrammaticand partly perspective, showing a second form of multiple inductors also embodying my invention;

Figs. 4 and 5 are diagrammatic views showing a railway train equipped with apparatus embodying my invention, and wherewith loss of signal at insulated rail joints is avoided.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, Bl andBZ are bars mounted on a vehicle of a railway train above and transverse to the traffic rails'l and la; The method of securing the two barsB and B2 to the vehicle is not shown in order to=simplify the 45 drawing as much as possible, and it will be understood that the bars are held in place above the rails to clear all roadside equipment. These bars are preferably placed on the vehicle spaced apart along the trackway; For example, they may be mounted at the oppositeends of the vehicle. BI and B2 each forms a' structure" on which inductor windings are wound and to this end the two bars mayor may not-be of magnetizable material. As will-appear hereinafter, e'achof the bars BI and B2 may be replaced by two independent bars,

one over each of said' rails should it seem de-' sirable to do so. As here shown,- each bar, B If and B2} is provi'ded with four cores or leg'sg Cl, C2; C3, and C4; each of which coresfproj'ects downward; the coresCl andCZ- beingdisposed on the oppo- 5' site sides of the rail hand. the cores C3 and C4 being disposed on the-opposite sides of the rail la. In the event the bars BI' and B2 are nonmagnetic material, the several cores formed 7 thereon may be located at the top of the bars and 10 project upward if desired.

The cores, C5, C2, C3, and C i'of bar Bl carry coils, l0, ll, I2, and I3, respectively-,an'd these coils are connected together in series to form an inductor winding'which I shall refer to hereinafter as inductor Ia; The coils Ill; I I, -I2, and

53 are preferably of substantially equal number of turns and resistances, and are so-arrangedthat electromotive forces induced therein' by magnetic flux created'by an alternating current which'flo'ws in the two rails in multiple are additive. To visualize this' arrangement the direction of current flowing in the traflic rails at a'particular instance'is indicated by double pointed arrows, and the" direction of the flux about the rai-ls'at this'par-ticular instance as'a result ofsuchcur rent, is indicated'by dottedlineson which are plac'ed'single pointed arrows. It follows that the inductor winding Ia consists of four vertical coils or portions, two of whichare disp'oseda-bove and on the opposite sides of rail 1; and the other two of which are disposed above and on the opposite sideso'f the rail la; and the separate coils are wound-onthe respective cores iri-adirectio'ri that when'connected together in series; the electromotive forces inducedin the different coils "as a result of a current'fiowing inthe railsin multiple add their-effects; Furthermore, it is*clear a foreign space magneticfield such aspfor example, that producedb'y nearby'power line'and 40 which field; is' illustrated imFig. 1,- by the arrows I4, will induce electro-mo'tive forces'in the coils" that cancel each other.

The coresCl, C2','C3, and C4of the bar B2 carry coils, I5; l6," l7, and I 8, res'pecti-velypand these coils are connected together in series to form a second inductor winding 'andwhich winding I-sh'a-ll refer to in'the' following description as inductor-1b.- The" coils l5, 16",11, and I8" are not'only preferably of equal turns and resistances .50 with'respe'ctto one another but they are also preferably similar to "the corresponding coils'of inductorIa. The coils I5 I6; I I; and l8=-arewound on the respective cores in such mannerthat el'ec-' tromotive' forces'in'duced therein due to current flowing in the traffic rails in multiple are additive. Consequently, the inductor winding Ib also consists of four vertical coils or portions, two of which are disposed on opposite sides of the rail l and the other two of which are disposed on the opposite sides of the rail la, the electromotive forces induced therein as a result of current flow ing in the rails in multiple adding their efiects, and the electromotive forces induced therein by a horizontal foreign space magnetic field cancelling each other.

The electromotive forces produced by the inductors Ia and II) are added together and the total applied to the input of a receiving apparatus on the vehicles, a contact of a circuit controller being interposed in the connection. As here shown, the inductors Ia and I?) are serially connected with the receiving apparatus by a circuit which starts from the right-hand terminal of a filter Fl and extends over back contact [9 of a directional relay DR, wire 25, coils l8, [1, I6 and I5 of inductor 11), wire 2i, coils lll, ll, 12, and iii of inductor Ia, wire 22 back contact 23 of the relay DR and to the opposite left-hand terminal of the filter Fl the filter in turn being connected with the input of the receiving apparatus RA over wires 24 and 25. The arrangement of the several coils of inductors Ia and Ib is such that not only the electromotive forces induced on the coils of each inductor are additive, but the electromotive forces of the two inductors combine and add their effects on the receiving apparatus RA. To illustrate this arrangement, arrows have been placed on the circuit elements to indicate the direction of the flow of current produced by the electromotive forces induced in the inductors Ia and It at the instant the rail current has the direction indicated by the double pointed arrows.

The receiving apparatus RA and the filter Fl may take any one of several forms usually provided for railway train signaling systems of the type herein invloved, and these devices are shown conventionally only for the sake of simplicity since the specific structure of such devices constitutes no part of my present invention. It is deemed sufficient for this application to point out that in railway train telephone systems, the receiving apparatus RA will ordinarily include a high gain amplifier and a demodulator effective to amplify and demodulate a carrier telephone current, and cause a current having the corresponding audio frequency to flow in the output to a telephone receiver such as a loud speaker LS. The filter Fl will include a circuit network effective to suppress frequencies outside of the desired band and to pass the desired voice frequencies to the receiving apparatus.

It follows that the inductors Ia and lb when taken together constitute a receiving inductor for transferring energy from the traffic rails to the receiving apparatus, and which inductor is balanced against the influences of a foreign space magnetic field transverse to the track, and which insures a relatively high sensitive pickup in response to a given current flowing in the trafiic rails.

For sending, that is, inducing electromotive force in the rails, the balanced receiving inductor described above is not as efficient from the standpoint of its mutual inductance with the rails as an inductor mounted with its axis horizontal and directly above the rails as close as clearances permit. During the sending of current from the vehicle, the immune feature is of no advantage and hence inductors of relatively high mutual inductance to the rails are desired. The bar BI is provided with two coils 26 and 21 which are wound on the bar substantially above the rails l and la, respectively. The coils 25 and 21 are preferably of equal turns and resistances and are connected in series to form a third inductor winding which I shall refer to as inductor 10. Thus the inductor consists of two horizontal coils one over each of said rails, the two coils being so connected and disposed that electromotive force induced in the two rails in response to current flowing in the coils are additive. In like manner, two coils 28 and 29 are wound on the bar B2, the coil 28 being substantially over the rail I and the coil 29 over the rail la. These two coils 28 and 29 are connected together in series to form a fourth inductor winding which I shall refer to as inductor Id. The coils 28 and 29 are preferably not only of equal turns and resistances with respect to each other, but are also similar to the corresponding coils of inductor I0, and are so wound that electromotive forces induced in the rails as a result of current flowing in the coils are additive.

In Fig. 1, the four inductors Ia, Ib, I0, and Id are connected in series with the transmitting apparatus on the vehicle, and all of them are used for sending, a contact of the directional relay DR being interposed in the circuit. Starting from the lower terminal of the transmitting apparatus TA, a transmitting circuit can be traced over front contact 30 of relay DR, wire 3|, coils 28 and 29 of inductor Id, wires 32 and 20, coils l8, ll, l6, and I5 of inductor 11), wire 2!, coils l0, l I, I2, and I3 of inductor Ia, wires 22 and 33, coils 21 and 26 of inductor 10, wire 34, front contact 35 of relay DR and thence to the upper and opposite terminal of the transmitting apparatus TA.

The transmitting apparatus TA may take different forms and is shown conventionally only since its specific type constitutes no part of my invention. It is deemed sufficient to point out that for a railway train telephone system the ap paratus TA will ordinarily include a generator of carrier frequency current, means for modulating the carrier with voice frequencies and an ampli fier for amplifying the output to a relatively high energy level.

An analysis of the transmitting circuit traced above will disclose the fact that current supplied to the circuit from the apparatus TA, and which current at a given instance flows in the direction of the arrows placed on the circuit elements, will be effective to create fluxes about the rails as indicated by the dotted lines, the fluxes produced by the several coils adding in their effects. These several fluxes will induce electromotive forces in the rails that will cause a current to flow in the trailic rails in multiple in the direction indicated by the double pointed arrows, the return path for such current being through the ground in the manner described and claimed in the L. O. Grondahl application for Letters Patent, Serial No. 450,135, filed May 6, 1930, on Electric train signaling systems.

For a given energy output of the transmitting apparatus the power induced in the traffic rails is substantially doubled by the twosimilar structures Bi and B2, when these two structures are far enough apart to be practically without mutual inductance to each other. In practicing my invention this condition will probably be realized by spacing the structures BI and B2 on the vehicle along the track 4 or 5 feet apart with a clearance above the rails of from 5 to 6 inches. For a single inductor the magnetomotive force will be NI where I is the current and ,N the number 'ofturns. This magnetomotive'force will produce a fluxlsufficient to induce an electromagnet force of say. Er inthe rails and the power transferred'to a rail circuit of the resistance of RrWill be (Er) /Rr. For inductors of the same size, their resistance varies substantially as the square of the number of turns. Hence, when two-inductors are-used and the resistance of each-isone-half the resistance. of the one inductor of the former case so that the current output of the transmitting apparatus remains constant, the number of turns of. each; of the latter inductors willbe and the total turns of the two inductors will'be- 1/ The flux. producedby these two inductors willbe correspondingly increased. and the electromotive force induced in the rails will be Consequently, the power transferred to the rail circuit of the resistance Rr will be WET) T E; 2 RT and which provides a relatively high pick-up sensitivity. With the directional relay DRenergized and its front contacts 30 and 35. closed, the transmitting apparatus is connected with the four inductors, Ia, Ib, I0, and Id in series, to furnish a transmitter. possessing relatively high mutual inductancewith the trafiic rails and a distribution of turns effective to-transfer a high ratio of energy fora given power output of the transmitting apparatus.

The directional relay DR may be controlled by current supplied from any convenientsource such as a battery. (not shown), the circuit being governed by a manually operated. controllerv or by a code device such as usually employed in systems of the type herein involved. As a matter of fact, the relay DR may be replaced by a manually operated controller should it seem desirable to do so.

The connection of the inductors and the coils thereof is here shown asseries but it is not essential'so long as the proper polarities are preserved.

It is possible to still further increase the power transfer by using more than twoinductor structures, thus, to use four similar structures spaced apart on the vehicle along the trackway would substantially double the power transfer by the structure of Fig. 1, the resistance of the four structures being maintained equal to. that of the two structures BI and B2.

In- Fig. 2, a modified arrangement of the inductors of Fig. l is provided, and in which the immune inductors Ia and II) are used for receiving thesameasirrFig; 1, but for sending the-induc+ tors. I and 111- only are employed; In" this in, stance,- thehorizontal coils 26 and 2'lof inductor I0 and thecoils 28 and 29 of inductor- Idare. serially connected with the-transmitting apparar tus over thefront contacts 30'and 35 of the di-- rectional relay DR independent. of the inductors Ia and I1). Itv is clear that with the proper pro:- portioning of. the several coilsof Fig. 2 this arrangement willproduceresults similar-to that. ofthe' apparatus of Fig. 1.

In Fig. 3,;another modified arrangement for the inductorsmounted on the vehicle spaced: apart alongv the trackway'is provided. In this arrangement the coils that. go to makeup theinductors Icand Idrare located at the opposite cornersof the vehicle. Four short barszB3, B4, B5, and'BG are. mounted on. the vehicle transverse to the trafiic railsat the opposite ends of the vehicle; the bars B3 and B4 being over rail land'bars B5- andBfioverrail la. These bars are similar to the. barsBl and B2 of Fig. 1, except for the fact that in this instance no vertical cores: are constructedthereon. The coils 26 and2-1 which make up inductor are mounted on thebars B4 and B6, respectively, the arrangement being such that coil 26 isdisposed above rail I and the coil.

2-1-is disposed above rail la. In like manner the coils. 28 and 29-Which make up the inductor Id are wound-on the bars B3 and B5, respectively, the coil being disposed abovethe rail I and the coil.29.being disposed above therail Ia. In other words, with the bars B6-and B4 mounted at the forwardand rear ends of a vehicle the coil 21'is.

positioned-above the rail la at the forward-end of the, vehicle and the coil-26 is positioned above the rail I at the rear end of the vehicle. In like manner. the coils 28 and 29 of the inductor 1d are located above the railsl and Id at the forwardand. rear end of thevehicle, respectively.

The inductors Ia and Id of Fig. 3 are connected in. parallel. with the input of the receiving apparatus. RA over back contacts 36 and 31 of the relay DR. as will be readily understood by an inspection. of the drawing. With the relay DR energized and its front contacts 38 and. 39. closed,. the inductors are transferred to the.

andcurrent flowing in the two railsin multiple willbe effective. to induce electromotive forces. in. the inductors that add their effect. Ihave found that the staggered arrangement ofthe inductor coils. of Fig. 3. will not only give the. increased transfer of power. the same as the inductorsof Fig. 1,.but. will also give a better balancedLcondition .for the .receiving and transmittingcircuits.

Referring to Figs. 4 .and 5, the reference characters Land. 4| designate the twoforwardve hicles of a railway train, and the reference char.- acters.42.and 43 designate the two rear vehicles of such train. For example, in Fig. 4, the vehicle 40'may be the locomotive, the vehicle 43, the caboose and the vehicles 4| and 42 cars of a freight train, the several vehicles being coupled together in the-usual manner and the intervening cars caboose 43,- apparatusembodying my invention will be mounted both on the caboose and on the locomotive, preferably on the tender. of the 10- comotive. As shown conventionally in Fig. 4, two structures BI and B2 with their associated inductor coils are disposed at the opposite ends of the Caboose 43 outside of the trucks. In like manner two barsl and their associated inductor coils will be mounted at the opposite ends of the tender of the locomotive 40 as shown conventionally at BI and B2 at the left-hand end of Fig. 4. It is clear that with the caboose 43 operated with either end first, one inductor bar will be ahead of the truck wheels and the other inductor bar will be behind the truck wheels.

Recalling that the communication current flows in the two trafiic rails in multiple and returns through the ground path, it is clear that with the train of Fig. 4 moving to the left, and a pair of insulated rail joints 44 and 45, one in each rail comes between the rear truck wheels of the car 42 and the forward truck wheels of the caboose 43, the rail current, which ordina rily flows in the rails, will pass around the high resistance of the insulated rail joints 44 and 45 by flowing from the rails through the wheels and metal parts of the caboose, the coupler between the caboose 43 and car 42 and thence back into the rails through the metal parts and wheels of that car. To visualize this path for the current around the insulated rail joints 44 and 45, a dotted line is placed on Fig. 4 and an arrow is added to indicate the direction of the flow of current at a particular instance. Under such conditions the effectiveness of the inductor coils mounted on the bar BI will be materially decreased. The inductive effectiveness of the coils mounted on the bar B2 at the rear of the caboose will, however, remain unchanged during this period that the insulated rail joints 44 and 45 pass between the car 42 and the forward truck wheels of the caboose and hence a momentary loss of control for the caboose apparatus will be avoided. In other words at locations where insulated rail joints are provided in connection with an automatic wayside signal system and which joints are staggered less than the distance between the rear wheels of the car 42 and the forward wheels of the caboose 43, the caboose inductor located at the rear end of the caboose will maintain the control of the equipment during the period these two insulated rail joints pass between the car 42 and the caboose 43. In the event a single inductor is mounted at one end of the caboose as heretofore proposed, a loss of control may occur as such insulated rail joints are passed, whereas by providing two inductors one at each end of the caboose, such loss of control will be avoided. In like manner the two inductors mounted on the opposite ends of the tender of locomotive 40 will function to prevent a loss of control for the locomotive equipment when a pair of insulated rail joints 46 and 41 (one in each rail) pass between the tender of the locomotive and the car 4|.

In Fig. 5, the train of Fig. 4 is illustrated as having advanced to a position where the insulated rail joints 44 and 45 are under the bar B2 at the rear end of the caboose. Under this condition the rail current will tend to flow to ground by the distributed ground path in advance of the insulated rail joints as illustrated by'the dotted lines of Fig. 5, and, consequently, will not flow under the inductor coils of B2. That portion of the current, however, that passes to ground between the location of the bar Bl at the forward end of the caboose and the insulated rail joints will be effective to influence the inductor coils mounted on BI and a momentary loss of control will be avoided. It will be apparent from an inspection of Fig. 3 that the staggered arrangement of the inductor coils will be eifective for avoiding a momentary loss of control at insulated rail joint locations.

Although I have herein shown and described only certain forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. An end to end railway train signaling system comprising a receiving apparatus and a transmitting apparatus on each of twovehicles of the train, a communication circuit between such vehicles including the traflic rails in multiple, and a circuit on each of said vehicles adapted to be connected to either the receiving or transmitting apparatus at that vehicle and including a plurality of windings, in inductive relation with each of the traffic rails to induce alternating current therein in multiple when the transmitting apparatus of that vehicle is connected with the circuit and to be responsive to current flowing through said rails when the receiving apparatus of that vehicle is connected with the circuit, and each of said circuits being characterized by having its windings distributed on the respective vehicle along the trackway for transfer of energy with the rails at the opposite ends of the vehicle whereby communication between the two vehicles is maintained while either of said vehicles passes over a pair of insulated rail joints one in each rail.

2. An end to end railway train signaling system comprising a receiving apparatus and a transmitting apparatus on each of two vehicles of the train, a communication circuit between such vehicles including the traffic rails in multiple, a first inductor on each vehicle mounted at one end of the vehicle and including two coils one disposed over each rail, a second inductor on each vehicle mounted at the other end of the vehicle and including two coils one disposed over each rail, a first circuit on each vehicle to connect the inductors of this vehicle with the transmitting apparatus to induce alternating current in the rails in multiple, a second circuit on each vehicle to connect the inductors of that vehicle with the receiving apparatus to inductively receive current in response to alternating current flowing in the rails in multiple, and a circuit controller on each vehicle effective to render either the first or the second circuit on the same vehicle active whereby two-way communication between the two vehicles is accomplished and maintained uninterrupted when either of said vehicles passes over a pair of insulated rail joints one in each rail.

3. In a railway train signaling system comprising a receiving apparatus and a transmitting apparatus on a vehicle of the train and a communication circuit including the traffic rails in multiple, in combination with the above instrumentalities a first and a second inductor on the vehicle each capable of inductively receiving electromotive forces due to a current flowing in the rails in multiple and of inducing electromotive forces in the rails when supplied with cur rent and which forces cause current to flow in the rails in'multiple, circuit means for selectively connecting said inductors with either the receiving apparatus orwith the transmitting apparatus'a'first and a second coil for each inductor, said-first coils being'inductively coupled with one rail and said second coils being inductively coupled with the other rail, and said coils mounted on the vehicle for transfer of energy with the rails at the opposite ends of the vehicle whereby the vehicle equipment remains effective to transfer energy with the rails as the vehicle passes over apair of insulated rail joints one in each rail.

4. In arailway train signaling system comprising a receiving apparatus and a transmitting apparatus on a vehicle of a 'train and a communication circuit including the traffic rails in multiple, in combination with the above instrumentalities'an inductor on the vehicle consisting of two windings in series one winding inductively coupled to one rail and the other inductively coupled with the other rail with said one winding disposed over said one rail at'the forward end of the vehicle and said other winding disposed over said other rail at the rear end of .the vehicle, and a circuit controller having different positions for selectively connecting said inductor to either the receiving or to the transmitting apparatus.

5. In a railway train signaling system comprising a receiving apparatus and a transmitting apparatus on a vehicle of the train and a communication circuit including the trafiic rails in multiple, in combination with the above instrumentalities a first inductor on the vehicle consisting of two windings one inductively coupled to each rail with one winding disposed over one rail at the forward end of the vehicle and the other winding disposed over the other rail at the rear end of the vehicle, a second inductor consisting of two windings one inductively coupled to each rail with one winding disposed over said one rail at the rear end of the vehicle and the other winding disposed over said other rail at the forward end of the vehicle, and a circuit controller having ,different positions for selectively connecting said inductors in parallel to either the receiving apparatus or to the transmitting apparatus.

6. In a railway train signal system comprising a receiving apparatus and a transmitting apparatus on a vehicle of the train and a communication circuit including the traffic rails, in combination with the above instrumentalities two bars mounted on the vehicle transverse with the traffic rails and each provided with four vertical core members, a first winding for each bar including a portion wound on each core, a second winding for each bar including a portion Wound on the bar substantially above each rail, a circuit controller having a first and a second position, a first circuit means effective in the first position of the controller to connect with the receiving apparatus the first windings of the two bars in series, said circuit means characterized by the fact that the portions of each winding are so connected together that electromotive forces induced therein due to current flowing in the rails in multiple are additive, and a second circuit means effective in the second position of the controller to connect with the transmitting apparatus the first and second windings of both bars in series, said second means characterized by the fact that the electromotive forces induced in the rails due to a current flowing in the several portions of said windingsare additive.

'7. In a railway trainsignal system comprising a receiving apparatus and a' transmitting apparatuson a vehicle of the train and a communication circuit including the traffic rails, in combination with the above instrumentalities two inductors mounted on the vehicle in inductive relation with the traffic rails,.a first winding for each inductor consisting of four vertical 'coils two of which are on opposite sides of one rail and the other two of which are on'opposite sides of the other rail, a second winding for each inductor consisting of a horizontal coil substantially above each rail, a circuit controller having a first and a second position, a first circuit means effective in the first position of the controller to connect with the receiving apparatus the first winding of said inductors in series, and a second circuit means effective in the second position of the controller to connect with the transmitting apparatus the first and second windings of said inductors in series.

8. In a railway train signaling system comprising a receiving apparatus and a transmitting apparatus on a vehicle of the train and a com munication circuit including the trafiic rails, in combination with the above instrumentalties two bars mounted on the vehicle each extending'transversely across the rails and each having four downwardly projecting legs, two of which are'on opposite sides of one rail and the other two of which are on opposite sides of the other rail, a first winding for each bar made up of a coil on each leg, said coils being connected in series in such manner that the electromotive forces induced therein by current flowing in the rails in multiple are additive, a second winding for each bar made up of a coil on the bar substantially above each rail, said coils being connected in series in such manner that the electromotive forces induced in the rails by current flowing in the winding are additive, a circuit controller having different positions, a first circuit means effec tive to connect the first windings of the two bars with the receiving apparatus and including one position of said controller, and a second circuit means effective to connect the second windings of the two bars with the transmitting apparatus and including another position of said controller.

9. In a railway train signal system comprising a receiving apparatus and a transmitting apparatus on a vehicle of the train and a communication circuit including the trafl-lc rails, in combination with the above instrumentalities, a first winding on the vehicle consisting of four vertical coils in series, two of which are on opposite sides of one rail and the other two of which are on opposite sides of the other rail, said Winding being characterized by the fact that the coils are so connected that electromotive forces induced therein by the magnetic field due to an alternating current flowing in the rails in multiple add their effects and electromotive forces induced therein by a space magnetic field transverse to the rails cancel their effects, a second winding on the vehicle consisting of two horizontal coils in series one located substantially above each of the rails, said second Winding characterized by the fact that the coils are so proportioned that electromotive forces induced in the two rails are substantially equal and add their effects, a circuit controller having different positions, a first circuit means to connect said first winding with the receiving apparatus and including one position of the controller, and a second circuit means to connect the second winding with the transmitting apparatus including another position of the controller.

10. In a railway train signaling system comprising a receiving apparatus and a transmitting apparatus on a vehicle of the train and a communication circuit including the traffic rails, in combination with the above instrumentalities a first winding on the vehicle disposed in inductive relation with the traffic rails and consisting of a plurality of vertical coils in series, said winding being characterized by the fact that the coils are so proportioned and disposed with respect to the rails as to be substantially immune to the efiects of space magnetic fields transverse to the rails and electromotive forces induced therein dueto current flowing in the rails in multiple are additive, a second winding on the vehicle disposed in inductive relation with the traffic rails and consisting of a plurality of horizontal coils in series, said second winding characterized by the fact that the coils are so proportioned and disposed with respect to the rails that electromotive forces induced in the rails due to a current flowing in said winding are additive, a circuit controller, a first circuit to connect the first winding with the receiving apparatus including one position of said controller, and a second circuit to connect the second winding with the transmitting apparatus including another position of the controller.

-11. Railway train signaling apparatus of the type comprising two magnetizable bars mounted on a vehicle transverse to the tralfic rails and each provided with four downward depending magnetic cores two disposed on the opposite sides of one rail and the other two disposed on the opposite sides of the other rail, a first winding for each bar including a portion wound on each of the cores of that bar and characterized by being serially connected that electromotive forces induced therein due to current flowing in the rails in multiple are additive, and when supplied with current induce electromotive forces in the rails that add their effects, a second winding for each bar including a portion wound on the bar substantially above each rail and characterized by being serially connected to induce in the rails electromotive forces which are additive when that winding is supplied with current, a circuit controller having a first and a second position, a first circuit means including the first position of the controller effective to serially connect the 'first windings of said bars with a receiving apparatus for energizing a signaling device with current picked up from the rails, and'a second circuit means including the second position of the controller effective to serially connect both the first and second windings of said bars with a source of current for supplying current to the trafilc rails.

PAUL N. BOSSART.

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