US1626928A - Railway-traffic-controlling apparatus - Google Patents

Description

INVENTOR: we

3 Sheets-Sheet 1 P H GEIGER RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Nov. 24. 1925 May 3 1927. 1,626,928

P. H. GEIGER RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Nov. 24. 1923 5 s t -s t 2 RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Novf24, 1923 3 Sheets-Sheet 3 Patented May 3, 1927.

1,626,928 PATENT OFFICE:

PAUL H. GEIGER, OF SWISSVALE, NENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENN-' SYLVANIA.

RAILWAY-TBAFFIC-CONTROIJIIING APPARATUS.

Application filed November 24, 1928. Serial No. 676,731.

My invention relates to railway traihc con-, trolling apparatus of the type. comprising train carried governing apparatus controlled by energy received from the trackway.

I will describe several forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view illustrating one. form of trackway apparatus embodying my invention. Fig.2 is a view showing one form of train carried governing apparatus adapted to co-operate with trackwayapparatus shown in Fig. 1. Fig. 3 is a view showing one modification of the apparatus shown in Fig. 1 and also embodying my invention. Figs. 1 and 5 are views showing two modifiations of the train carried apparatus of Fig.- 2 and also embodying my invention. Figs. 6 and 7 are detail views showing the construction of relay W of Fig. 4.

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

Referring first to Fig. 1, the reference characters 1 and 1'1 designate the'track rails of a railway over which trafiic normally moves in the direction indicated by the ar- 7 row. These track rails are divided by means of insulated joints 2 into a plurality of successive track sections A-B, BC, etc. Each such track section isprovided with a track relay designated by the reference.

character R with a suitable exponent. Each track relay comprises two windings 6 and 7. One winding 7 of each track relay R is connected across the rails adjacent the entrance end of the section. The remaining winding 6 of each trackrelay is constantly supplied with alternating current from secondary 11 of an associated line transformer designated by the reference character T with an exponent corresponding to the location. The primary winding-9 of each transformer T is constantly supplied with alternating current from some suitable source such as a generator K over line wires 8 and 8. It is therefore clear that contacts 25 and 26? of each track relay are responsive to the relarelay passin from secondary 11 of transformer T tirough wires 75 and 27, contact 26 of track relay B in the reverse or normal -position,' wires 28 and 29, winding of relay H and wires 30 and 74 back to secondary 11 of transformer T The supply of track circuit current to each track section is controlled b the auxiliary relay for the section next 1n advance. For example, when relay H is de-energized a circuitis closed over which current flows from secondry 13 of transformer T through wire 16, im edance 17 and condenser 70in multiple, Wire 18, back contact 19 of relay H wire 22, rail 1 of section AB, through windin 7 of relay B or the wheels and axles 0% a train occupying section AB', to rail 1 of the section, thence by wires 21. 9.0 and 31, back contact 23 of relay H and wire 24 back to secondary 13 of transformer T When this cirouitis closed section A-B is supplied with track circuit current of one relative polarity which I will hereinafter term reverse relative polarity. VVh'en relay H is energized, track circuit current flows from secondary 13 of transformer Tf, through wire 16, impedance 17 and condenser 70 in multiple, wire 18, front contact. 19 of relay H wires 20 and 21 to rail 1 of section A-B, thence as befor to rail 1 of the section, and wire 22, front contact 23 of relay H, and wire 24 back to secondary 13 of transformer T When this circuit is closed section A B is supplied with track circuit current of the other relative polarity which I will term normal relative polarity. The frequency of each of these currents is of. course the'same as the frequency of the generator K. I shall hereinafterrefer to this fre uencyas low fre uency.

. cans are also provi ed for at times sup plying the rails with a track circuit current the frequency of which is different from that suppliedby secondary 13. To accomplish rovided with a this. result. each section is the double Wave rectifier designated b reference character G with a distinguishing exponent. This rectifier may be of any suitable form and as here shown is a copper oxide rectifier of the ty e described in an application for United gtates Letters Patent, Serial No. 1111 filed January 7, 1925 by Lars O. Grondahl for uni-directional current carrying devices, this application being a continuation of an earlier application, Serial No. 541733, filed March 7, 1922, by Lars O. Grondahl and Frank H. Nicholson relating to the same subject-matter. Referring particularlyto rectifier G, the input terminals (1 and b of this rectifier are connected across secondary 10 of transformer T and the output terminals g and h are connected with primary 14 of an auxiliary transformer U A condenser 33 is interposed between winding 14 and rectifier Gr for the purposeof counter-acting the reactive impedance of the winding 14 in its tendency to smooth out the pulsations of the current supplied by rectifier G. With this arrangement the alternating current supplied by secondary 10 of transformer T is changed by rectifier G into a pulsating uni-directional current the periodicity of which is twice the frequency of generator K. \Vhen this pulsating current flows through primary 14 of transformer U there is induced in the secondary 15 of this transformer an alternating electromotive force, the frequency of which is the same as the periodicity of the pulsating current flowing in primary 14 and hence is twice the frequency of generator K. I shall hereinafter refer to this frequency as hi h frequency.

When relay H is energizef, secondary 15 of transformer U is connected. with section A--B over a circuit which passes from secondary 15 through wire 34, impedance 35, wire 36, condenser 37, wire 21, rail 1 of section A-B, winding 7 of relay B or the wheels and axles of a train in the section, rail 1, wires 22 and 38, front contact 39 of relay H and wire 40 back to secondary 15 of transformer U. Under these conditions, in addition to the track circuit current of normal relative polarity supplied to section A--B at the frequency of generator K by secondary 13 of transformer T there is also supplied to section A-B bytransformer U a track circuit current of twice the frequency of generator K. By means of reactive impedance 35 and condenser 37 the circuit including secondary 15 of transformer T is tuned to approximate resonance at twice the frequency of generator K. As a result this circuit offers a low impedance to the high frequency current but a high impedance to any low frequency current which may be flowing in the circuit.

The impedance 17 and condenser which are inserted in circuit with secondary 13 are tuned to an approximate resonance at twice the frequency of generator K. The impedance 17 and condenser 70 therefore constitute a filter designated by the reference character F The purpose of this filter is three-fold. First, it offers a high impedance to any high frequency current flowing through the circuit of secondary 13; second, it limits the output of secondary 13'when its terminals are short-circuited by the wheels and axles of a train occupying section AB; third, it displaces the phase of the current flowing through the rails of section AB with respect to the electromotive force supplied by secondary 13 and hence with respect to the current supplied by transformer U This phase displacement is desirable to prevent improper operation of some types of track relays R which operate on the induction motor principle.

Located at the entrance end of each section is a trackway signal designated by the reference character S- with an exponent corresponding to the location. Each signal S, as here shown, comprises three light units 3, 4t and 5 adapted when energized to indicate proceed, caution or stop, respectively. Each signal is controlled by the/associated track relay in such manner that when this relay is energized in the normal direction contacts 25 and 26 are swung to the right and unit 3 is energized, when the associated track relay is energized in the reverse direction the contacts 25 and 26 are swung to the left and unit 4 is energized, and when the associated track relay is deenergized, contacts 25 and 26 assume an intermediate position, thus de-energizing the associated auxiliary relay H and energizing unit 5. Energy is supplied to the various units of each signal S from a secondary 12 of the associated line transformer T as will be clear from the drawin As shown in the drawing the section to the right of point C is occupied by a train V. Track relay R is therefore de-energized. As a result contact 26 of relay R occupies an intermediate position and interrupts the circuit for relay H which therefore becomes de-energized. The circuit for unit 5 of signal S is therefore closed and. this signal displays a stop indication. At the same time the de-energization of relay H disconnects transformer U from the rails of section BC- and therefore interrupts the supply of high frequency current to this section. The circuit for secondary 13 of transformer T is closed however at back contacts 19 and 23 of relay H and section BC is therefore supplied with low frequency track circuitcurrent of reverse relative polarity. As a result relay R is energized in the reverse direction thus completing the circuit for unit 4 of signal S which displays a caution indication. The closing of reverse contact 26 of relay R also completes the circuit for relay H which is therefore energized. Low frequency track circuit current of normal relative olarity 1S therefore supplied to the rails 0 section AB by secondary 13 of transformer T and high frequency track circuit current is also supplied to the rails of this section by transformer U The low frequency track circuit current of normal relative polarity supplied to relay R picks up this relay in the normal direction therebycompleting the circuit for unit 3 of signal S and causing this signal to display a proceed indication.

Relay H is also energized and the supply of track circuit current to the section to the left of A is the same as that just described for section A-B.

Referring now to Fig. 3, the supply of low frequency track circuit current of normal relative polarity, and the supply of high frequency track circuit current, are controlled in the same manner as explained inconnection with Fig. 1. When relay H is de-energized, however, low. frequency track circuit current is supplied to section A-B over a circuit which passes from secondary 13 of transformer T through Wire 16, filter F wire 18, back contact 19 of relay H wire 72, rail 1 of section AB, winding 7 of track relay B or the wheels and axles of a train in the section, rail 1, wire 73, back contact 23 of relay H wire 24 back to secondary 13 of transformer T When relay H is de-energized, therefore, section AB is supplied with low frequency track circuit'current of reverse relative polarity between the entrance end of the sec-' tion and an intermediate point t in the section. The control of relays H and signals S are the same as in Fig. 1. I

It will thus be seen that the supply of track circuit current to section AB is as follows: When section BC is occupied low frequency current of reverse relative polarity is supplied to section A-B from the entrance end to' an intermediate po nt 1n the section, and the supply of high frequency track circuit current is completely discontinued, an when section B--C is unoccupied, section A-B is supplied with low fre-' quency current of normal relative polarity and with high frequency current throughout the length of the section.

In orderto assure the de-energization of each track relay when the section next in advance is being supplied with track circuit current at pointt, and a train is occupying the associated sectionbetween the exit end of the section and point t, I provide each section with an auxiliary track relay designated by the reference character L with an exponent corresponding to the location, and connected across the rails adjacent the exit end of the section. Each track relay L controls the supply of current to winding 6 of the track relay R connected with the entrance end of the corresponding section. Referring particularly to relay R the circart for the relay passes from line wire 8, through wire- 89, front contact 90 of track relay L, wire91, windingG of relay R and Wire 92 back to line wire 8. It is thus plain that relay R will be positively de-energized wheg a train occupies any portion of section .In the form of train carried governing apparatus illustrated in Fig. 2, the reference characters 0 and P designate two pickup coils carried on the train and in inductive relation with thetrack rails. .The energy induced in each of these pick-up coilsO and P is amplified by some suitable form of amplifying apparatus here illustrated as electron tubes D and D, respectively. Each of the amplifying devices D and D is provided with a filament 48, a grid 49 and .a plate 50. Some suitable source of energy, as a battery 52 is provided for heating the filament 48 of each tube. Pick-up coil 0 is connected across filament 48 and grid 49 ,of tube D, and in similar manner pick-up with a plate circuit including a source of direct current such as a battery 53 and the primary winding 54 of 1 transformer E, which winding is tuned, by means of a condenser 57 to resonance at the frequency of generator K. The secondary 55 of transformer E is connected through a rectifier J with the winding of a relay W. The plate circuit for tube D includes primary 54 of a transformer E, similar to transformer E and a battery 53". Primary 54 of transformer E is tuned to resonance at twice the frequency of generator by means of a con-- denser 56 shunted across the winding. The secondary 55 of transformer is connected through a rectifier J to the winding of relay W.

It will be clear from the foregoing that when the train occupies a stretch of track, which is supplied with low frequencytrack circuit current, that is, track circuit current which is supplied to the rails of a section by secondary 10 of a line transformer T in Figs. 1 or 3 will haveno effect on relay W. This high frequency track circuit current will however induce in pick-up coil P a voltage which is effective to energize relay W, and. due to the tuning of the grid circuit and the plate circuit of tube D, relay W will not be affected by the presence of low frequency track circuit current in .the stretch of track occupied by the train.

The relays W and W may control any suitable form of governing apparatus. .As shown in the drawing this apparatus comprises three indicators such as electric lamps 56, 57 and 58. These lamps may be provided with suitable indicia to inform the engineman of traffic conditions in advance. Lamp 57 is provided with a circuit which passes from a source of energy, here shown as a battery 59, through wire 60, front contact 6l61 of relay W, wire 62, front contact 6363 of relay W, wire 64:, lamp 57,

and wires 65 and 66 back to battery 59. This circuit is closed only when relays W and W" are both energized, that is, when the train occupies a stretch of track which is being supplied simultaneously with low frequency and high frequency track circuit current, under which conditions lamp 57 is lighted to display a proceed indication. Lamp 58 is'provided with a circuit which passes from battery 59, through wire 60, front contact 6161 of relay 1W, wire 62, back'contact 63- 63 of .relay W, wire 69, lamp 58 and wire 66 back to battery 59. This circuit is closed only when relay W is energized and rela W is de-energized, that is, when the portion of track occupied by the train is being supplied With low frequency track circuit current but not with high frequency track circuit current.- Under these conditionslamp 58 is lighted to display a caution indication. When the supply of low frequencycurrent to the portion of track occupied by the train is interrupted, relay W is de-energized and current flows from battery 59, through wire 60, back contact 616l of relay W, wire 67, lamp 56, and wires 68 and 66 back to battery 59, thus displaying a stop indication.

As a train equipped with the apparatus illustrated in Fig. 2 passes through the stretch of track shown in Fig. 1 with a train V occupyingthe section to the right of C, the operation of the apparatus is as follows; As the train proceeds through the stretch it will be supplied with both high frequency "and low frequency track circuit current as far as point B. Relays W and W are therefore both energized and lamp 57 is lighted to give the engineman a proceed indication. As the train enters section B-C the interruption of the supply of high freeaaeae quency track circuit current causes relay W to become de-energized whereas relay W continues to be energized by low frequency track circuit current. Lamp 58 is therefore energized and a caution indication is received aboard the train. In the section to the right of C both the high frequency and low frequency track circuit currents are cut ofi by train V andso as the following train enters this section both relays W and W are de-energized and lamp 56 is lighted to display a stopindication.

If a train equipped with the apparatus shown in Fig. 2 traverses the stretch of.

sible for the engineman to stop the train before entering the occupied section to the right of point C.

With relays W and W constructed as shown in Fig. 4 the amplifyin apparatus of Fig. 2 maybe omitted. Re erring particularly to relay W this relay is of the DArsonval moving coil type comprising a U-shaped magnetizable core 78 and a movable winding 82 interposed between the legs of this core. As shown in detail in Figs. 6 and 7, this coil 82 is supported in a suitable frame pivotally supported at points '90 and 90 and provided with an arm 91 for operating a movable contact member 61. The reluctance of the magnetic circuit including core 78 may be reduced by means of a fixed magnetizable member 81 placed 1 within the winding 82. A winding 7 9 supplied with current from a battery 80 serves to create a magnetic flux in core 78. The

vmovable winding 82 of relay W is connected by means of a rectifier J with pick -up coil O, the circuit including the pick-up coil being tuned to resonance at the frequency of generator K as by a condenser 76. It will be plain that alternating current of the proper frequency induced in pick-up coil 0 will be translated by rectifier J into a pulsating uni-directional currentwhich will flow through movable coil 82 of relay W. lhe reaction of this current and the flux throu h core 78 causes contact member 61 to e moved into the position shown in the drawing against the bias exerted by gravity thus closing its front contact 6161. When relay W is not being supplied with such pulsating current, as when the train occupies a stretch of track to which the supply of low frequency track circuit current is interrupted, member 61 moves downward under the infiuenceof gravit to close its back contact 61-61". Relay is similar to relay W and its movable coil 82 is supplied with current through rectifier J from coil P. The pick-up coil P is tuned by means of condenser 77 to resonance at twice the frequency of generator K. Relays constructed in this manner are highly sensitive and may be made to o erate on the small amounts of power trans erred b induction from the track rails to the pic -'up coils. Relays W and W of Fig. 4: control indicators 56, 57 and 58 in the same manner as in ig. 2 and the operation of this apparatus Wlll be understood without further explanation.

Ifthe frequency of the track circuit currents are so chosen that iron core pick-up coils may be used, the pick-up circuits may be tuned as shown in Fig. 5. In this view the pick-up coil P comprises a magnetic core 84 and a winding 83 -thereon. The core 84 also carries an auxiliary winding 85 which is tuned to resonance, by means of.

condenser 86 at the frequency of the current which it is desired to pick-up. The two terminals of winding 83 are connected by means of asymmetrical units 87 and 88 with one terminal of the movable winding 82 of relay W. The other terminal of winding 82 is connected with the electrical midpoint is of winding 83. I have discovered that pick-up apparatus constructed in this manner is highly eflicient.

Although I have herein shown and described only a few 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. Railway traflic, controlling apparatus comprising means responsive to traflic conditions in advance for at times supplying periodic current at one frequency to the track rails of a section, and for at times supplying said rails with alternating current of one relative polarity or the other at another frequency, and governing means res sponsive to said currents.

Railway trafiic controlling apparatus comprising a stretch of railway track, means responsive to traflic conditions 'in advance for attimes supplying periodic current of one "relative polarity or the other at one frequency to the rails of the stretch, and for at times also supplying said stretch with periodic current at a different frequency, and governing means responsive to said currents.

3. Railway trafiic controlling apparatus comprising a stretch of railway. track, a circuit tuned to approximate resonance at one frequency for supplying periodic current of one relative polarity or the other to the trackway, a circuit tuned to approximate stretch.

a circuit tuned to approximate resonance at a different frequency for at times supplying periodic current to the trackway, and train carried governing means responsive to said current.

5. Rail-way trailic controlling apparatus comprising a stretch of railway track, a source of periodic energy, means for at times supplying current of one frequency from said source to said stretch, and means for at times supplyingsaid stretch with current of a different frequency from said source.

6. In combination, a stretch of railway track, and a single source of energy ar ranged to at times supply said stretch with periodic currents of two' different periodicities simultaneously. I

7. In combination, a stretch of railway track, a double wave rectifier having output terminals and input terminals, means for supplying alternating current to theinput terminals of said rectifier, a transformer having its primary winding connected with the output terminals of said rectifier, and means responsive to traffic conditions for at times connecting the secondary winding of said transformer with p the rails of-said transformer with the rails of said stretch,

and governing apparatus responsive to currentin said rails.

9. In combination, a stretch of railway track, a double wave rectifier having output terminals and input terminals, means for supplying alternating current to the input terminals of said rectifier, a transformer having its primary winding connected with the output terminals of said rectifier, means responsive to traffic conditions for at times connecting the secondary winding of said,

transformer with the rails of said stretch, and train carried governing apparatus re; sponsive to the frequency of the current in said rails. v

10. Incombination, a stretch of railway track, a double wave rectifier having output terminals and input terminals, means for supplying alternating current to the input terminals of said rectifier, a transformer having its primary winding connected with the output terminals of said rectifier, and means-responsive to traffic conditions for at times connecting the secondary winding of said transfor'mer with the rails of said stretch, and for. at times supplying said stretch with alternating current of the same frequency as that supplied to said rectifier, and governing apparatus responsive to the frequency of the current supplied to said stretch.

11. Railway trafliccontrolling apparatus comprising a stretch of railway track, means for at times supplying said stretch with periodic current of one relative polarity or the other at one frequency, a signal for said stretch controlled by such current, means for at times supplying said stretch with periodic current of a different frequency, and train carried means responsive to our rents flowing in such stretch.

12. Railway traffic controlling apparatus comprising a stretch of railway track, .a source of periodic energy, means responsive to traffic conditions for at times supplying said stretch with alternating current of one frequency from said source, a trackway signal controlled solely by said current, means for at times supplyingsaid stretch with al-i ternating current of a different frequency from said source, andtrain carried governing means controlled by both said currents.

13..Railway traflic controlling apparatus comprising a source of periodic energy, means for at times supplying the trackway with alternating current ofv one frequency, static means including a rectifier for at times supplying the trackway with alternating currentof a different frequency from said source, two electro responsive devices selectively responsive to said currents, and governing means controlled .by said devices.

14. Railway traffic controlling apparatus comprising a source of periodic energy, means for at times supplying the trackway with alternating current of one frequency, static means including a rectifier for at times supplying the trackway with alternating current of a different frequency from said source, two electric circuits each including means responsive to one of said currents, and governing apparatus controlled by said circuits.

i 15. Railway traffic controlling apparatus comprising a source of periodic energy, means for at times supplying the trackway with alternating current of one frequency, static means including a rectifier for at times supplying the trackway with alternating current of a different frequency from said source, two pick-up circuits on a train each tuned to approximate .resonance at the fresource, two pick-up circuits on a train each tuned to approximate resonance at the frequency of one of said currents, an electro responsive device associated with each such pick-up circuit, a rectifier for transferring energy from each said pick-up coil to the associated device, and governing means controlled by said devices. 1 17. Railway traffic controlling apparatus comprising a source of periodic energy, means for at times supplying the trackway with alternating current of one frequency, static means including a rectifier for at times supplying the trackway with alternating current of a different frequency from said source, means on a train for receiving current induced by said currents in the trackway, means for amplifying said inducedcurrents, and governing means con trolled by such amplified induced currents. 18. Railway traffic controlling apparatus comprising a source of periodic energy, means for at times supplying the trackway with alternating current of one frequency,

static means including a rectifier for at times supplying the trackway with alternating current of a different frequency from said source, two electroresponsive devices on a train, two electric circuits for receiving energy from the trackway, and a rectifier in each said circuit for transferring energy directly from the associated circuit to one of said devices.

19. Railway traffic controlling apparatus comprising a source of periodic energy, means for at times supplying the trackway, with alternating current of one frequency, static means including a rectifier for at times supplying the trackway with alternating current of a different frequency from said source, two pick-up coils on a train for receiving energy at different frequencies from the trackway, a relay for each such coil,

and a rectifier for transferring energy from each such coil to the associated relay.

20. Railway trafiic controlling apparatus comprising a source of periodic energy, means for at times supplying the trackway with alternating current of one frequency, static means including a rectifier for at times supplying the trackway with alternating.

current of a different frequency from. said source, two pick-u coils in inductive relation with the trac (way and. each tuned to approximate resonance at the frequency of one of said currents, a relay for each said coil, and a rectifier for transferring energy directly from each said coil to the associated relay.

2-1. In combination, a stretch of railway track, means for at times supplying said stretch with alternating current; a train carried relay comprising a magnetic circuit, means for producing a magnetic flux in said circuit, and amovable conductor interposed in the path of flux; a pick-up coil on the train in inductive relation with the trackway, a rectifier for transferring energy from said coil directly to said conductor, and governing means controlled by said 'conductor.

22. In combination, a stretch of railway tracli, means for at times supplying said stretch with alternating current; a magnetic core on a train in inductive relation with the trackw'ay, a relay, a first winding on said core connected with said relay, a second winding onsaid core tuned to approximate resonance at the frequency of said current for tuning said first winding and its circuit to approximate resonance at the frequency of said current, and governing means controlled by said relay.

23. In combination, a stretch of railway track, means for at times supplying said stretch with alternating current, a magnetic core on a train in inductive relation with the trackway, a relay, governing means controlled by said relay, a first winding on said core having its electrical mid point connected with one terminal of'said relay by means of a conductor, and having its two extremities connected with the remaining terminal of said relay through asymmetrical units, and a second winding on said core tuned to approximate resonance at the frequency of said current for tuning said first winding and, its circuit to approximate resonance at the frequency of said current.

24. In combination, a stretch of railway track. means for at times supplying said stretch with alternating current; a magnetic core on a train in inductive relation with the trackway, a relay on said train, a first winding on said core connected with said relay, a rectifier interposed between. said first winding and said relay, governing means controlled by said relay, and a second winding on said core tuned to approximate resonance at the frequency of said current, for tuning said first winding and its circuit to approximate resonance at the frequency of said current.

25. Railway trafiic controlling apparatus comprising a source of periodic energy, means for at times supplying the trackway with alternating current of one frequency,

static meansincluding a rectifier for at times supplying the trackway .with alte-rnatin current of a different frequency from said source, two pick-up coils in inductive relation with the trackway and each tuned to approximate resonance at the frequency of one of said currents, a relay for each said coil, comprising a ma 'etic circuit havingla unidirectional flux owing therethrough and a movable conductor in said circuit, a rectifier .for transferring energy from each said (coil to the said conductor of the associated relay, and governing means controlled by said mov able conductors.

26. Railway trafiio controlling apparatus comprising a stretch of railway track, means for at times supplying the entire stretch with alternating current of one frequency and for at times supplying a portion only of the stretch with alternating current of a different frequency, and train carried governing means responsive to such currents.

27 Railway traffic. controlling apparatus comprising a stretch of railway track, means for at times supplying a portion only of said stretch with alternating current of one relative polarity at one frequency, and for at other times supplying the entire stretch with current of the other relative polarity at the same frequency and with alternating current of a different frequency and governing means controlled by said currents.

28. Railway traffic controlling apparatus comprising a stretch of railway track, means for at times supplying a portion only of said stretch with a1 ernating current of one fre-' quency and for at other times supplying the entire stretch. with alternating current of two different frequencies from a single source of periodic energy, and train carried govern ing means responsive to such currents.

29. Railway trafiic controlling apparatus comprising a stretch of railway track, means for at times supplying a portion only of said stretch with alternating current of one frequency and for at other times supplying the entire stretch with alternating: current of said one frequency and also with current of a different frequency, a trackway signal con trolled by current of said one frequency, and train carried governing means responsive to currents of both said frequencies;

' 30. .In combination, a stretch of railway track, an alternating current transformer having two secondary windings, means for at times connecting one'said secondary directly with said stretch, and static means for at other times supplying said stretch from said second winding with current of. a

freguency different from that supplied to supplied with alternating current of one frequency and two secondaryvwindings a circuit tuned to resonance at said one frequency for at times connecting one said secondary with the trackway, an auxiliary transformer and a rectifier for at times supplying alternating current of a different frequency to the trackway from said secondary, and train carried governing means controlled by current in the trackway. l

32. Railway traffic controlling apparatus comprising a transformer havingaprimary supplied with alternating current of one frequency and two secondary windings, a circuit tuned to resonance at said one frequency for at times connecting one said secondary with the trackway, an auxiliary transformer and a rectifier for at times supplying alternating current of a different frequency to the trackway from the second said secondary, and train carried governing means responsive to the frequency of the current in said trackway.

33. In combination, a forward and arear section of railway track, a relay arranged to be de-energized only when said forward section is occupied, means including afront contact on said relay for supplying the entire rear section with alternating currents of two different frequencies simultaneously, means including a back contact of said relay for supplying a portion only of said rear section with alternating current of one only of such frequencies, and train carried governing means responsive to the frequency of the current in said section.

34. In combination, a forward and a rear section of railway track, a track relay for each end of said forward section, means 101- at times supplying current to a portion only of said "forward section, means for supplying alternating current to the entire rear section when both said relays are energized but to a portion only of said rear secerning means controlled by said second relay.

Train carried receiving apparatus comprising a magnet-1c core, a relay, a first winding on said core and connected to said relay, a second winding on said core having tuned impedance means in circuit therewith to tune the first winding and its circuit, and governing means controlled by said relay.

37. Train carried receiving apparatus comprising a magnetic core, a relay, governing means controlled by said relay, a first winding on said core, a plurality of asymmetric units connected between one terminal of said relay and the ends of said first winding, a conductor connecting the electrical mid-point of the winding to another terminal of the relay, and a second winding on said core having a condenser in circuit therewith for tuning said first winding and its circuit.

38. A train carried receiver, comprising a magnetic core, a relay, a first winding on said core connected with said relay, a rectifier interposed between said first winding and said relay, governing means controlled by said relay, and a secondwinding on said core having a condenser in circuit therewith for tuning said first winding and its circuit.

In testimony whereof I affix my signature.

PAUL H. GEIGER.

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