US2000917A - Train control system - Google Patents

Description

May 14, 1935. T. BODDE 2,000,917

' TRAIN CONTROL SYSTEM Filed Oct. 50. 1925 2 Sheets-Sheet 1 I I a p l I 1 H INVENTOR [I Theodore Bod ATT RNEYS May 14, 1935.- r. BODDE 2,000,917

TR AIN CONTROL SYSTEM I Filed Oct. 30. 1926 V 2 Sheets-Sheet 2 INVENTOR I Theodore Boolde I BY g ATTORNEYS- Patented May 1935 or -positioning of said vehicle "carried inductor relatively to a roadside inductor which embodies circuit control meansdevoidof an energy-source prior induction train control 1 systems ot which I' am awa,re,-an activating operation of 'the vehiclecanied circuits was produced by the transmission of 1 some energizing influence from the roadside vinductor to the vehicle carried inductor obtained by energizing the roadside -in-' ductor either directly by means of a'.-sou 1 ce of energy located on the roadside -or indirectly by locating the sourceof energy on the moving vehicle 'and ireflexing" or-retransferring'said energy V 5 through cooperating vehicle carried and roadside inductors from the vehicle to and {through the I I ductors and'back to the 'vehicle' appa ratus: }By'- my present invention I ropose to eliminate the principal obj ections to these *systoms of prior-design; which obj ections'fhnve their :origin either -the nec'essity' of "using aroadside energy-tor the roadside inductors-or in the-nece'spnthegvehiclezm sity cfvwusing a multiplicity-bot inductors-forkehe energy'source islocated A corollaryiprime objectof niyipresentiinven- 4 tion relates ;to the a provision .of ;,-a.n impitovedinduction train.=,.control -;system which :18- single roadside inductor mayzbelemployednndselectively' operated to pmduoeiin ;a vehicleicarriedinductor mGMXSLEJILDmbEIEOf operations corresponding to zthetconditionsijof the -.;roudside, "whichroperations ;comprise :the production of a; conditionin the Vhi0l8fimie d inductor means ;to produce a. trippins 501' gtrai n hcontrol stopp ns op rat o -L n the gtherxehicle carried inductor means, to ;permit a,

passive @state inythe vehicle carried ,zspparatus;

zthstpris,. to "permit the vehicle to er ads l-controlling lstation without .any ;oper- -ation being produced. in-thetvehicle carried appain the vehiclecarriedinductor meanstor 'eflecti'ng some other. operationttherein in response; for example: to a, wear or j ceution. roadside: condit-ion. A further pprimeobject of n my present vin- =vention relates to r the provision of an induction =system=of this character in which the-thirdcon I a n Lbs" mesne assignments, .to (tamer- 1.1v v

s 'N- 1 were:

carried iapparotus und: in which the cleer or {-coutionf operating conditions; the "vehicle carried apparatus may beproduced bymeanspt V aroadsideinductor devoid of a source of energy,

the results attained be'ing therefore capable-of 3} Other princ'pal objects of invention will become evident as the description proceeds, and to theaccomplishment of thle foregoing and suchother objects a.s 'iavill herc'ainaiterv appear, my invention consists the elements'andtheirrelation one to-the other incircuit combinations ts-hereinafter"rnore perticularly described and sought to b "11 1 1136. the claims; referencebeing had to {the accoinpanying drawings which show the pro fined emmdiment i m tioni and in which;

is a wiring diagrammatic 'vie wof tqqqpr ating fvehicle carried and 'roadsidefinductive hp? poratus embodying the principles or my invert.

- 2fis adiagrammatic "view shj wm n ins characteristics andexempliiying' theund r; lyin'gcprihciples,of the'systemof myinvention'. 30

Referring nhwmore 'in detail to the drawings 1- 9 w mt rd .into lU- S- Bl t n 1 0.v

;1, 73s,-73s granted c. 10', 1929, w n h c m rises inductively coupledcoils consisting of a .primery' r'coilP' and. a, secondaryicoil s 'inductivelyjcoupled thereto .for the' transmission of nu rmm fthe primaryto the jsecondary coil, thej sgid fprin ery coil being; arranged "in .a primary circuitva designatedby the legend Primary in Fig'. '1, which circuit is connected to the lnainsgmnndsl'i of tern i il ren u ceipf ener yo-sucih'as flthe en r e! nd d s c n ar .c il' binz arranged in eisecondory circuitb also 'designnted the drs P ime le en fie on wfi Both primary and secondary coils P 'and S are preferably wound on cores l2 and "I3 which are' preferably laminated and the primary P is pref-n;

--rat'us, combined with-a thirdconditionzproducible, ft i o d r s inopposite Sense thereto I so as toactinbucking' or OPP SiHEwYCIQtiOD theretof for the purpose of neutralizing the @under -fcertoin :conditions as described and claimed-Fin :the ypatenti' to" A. G." smut "moi,

:fThe vehicle carried coupled-coihconibination Pi v is employed for normelly energizingia-;ve-

tirippingjoperation fromtaking place. fI havediscovered that in a systemof this charsaid field coil 1' being connected to the generator G by means of the conductors l and H and the said armature coil r being connected directly in the secondary circuitb. 'Ihearmature r is provided with a movable circuit "controlling member l5 for selectively operatin'ga contact mechanism al y designated as c forin turn selectively controlling the train control circuits to be described-hereinafter. I 1

As disclosed in the aforementionedcopending application of A. G. Shaver, Serial No. 506,595

of 1921, now; matured into U.,S.Patent No.&1,738,- .736 grantecLDec; 10,1929 the vehiclencarried transformer combination -P- -S operates to normallyenergize the relayR by the transmission of suificientflux from the primary? to the secondary s toeii'ectively energize the relay coil of the relay- R. When, however, the coupled coil. combination P-S moves over in proximity to an inert roadside element, the-flux from the .primaryl is diverted to and through theroadside inert element and shunted from; the secondary coil, S in a,- degree suliicient-to effectively deenergize the relay R When the relay R. is energized'underfthe first or normal condition of the: inductively coupled, coils P and S,-the cir cuit controlling member 15 thereof assumes a normal position, such as shown in fulllines in Fig. :1' .of'. the 'dra'wingsjwhich position is indicated as x, and when the relay i'sefiectively deene'r gized by the shunting of the secondary, the circuit controlling member l5 of the. relaymoves to a neutral position suchas indicated by the dotted line position y. In the operation of this system it is also known that when the roadside inert element is provided with. an .energyless circuit, thesaid circuitmay be'iclosed to permitthe vehicle carried inductor means to .pass the roadside inductor. '(onc'lose'd circuit) without "any'substantial diversion or shunting of the flux'from ,tliesecondary. S and hence without j modifying .thefoperationof the relay R, the circuit controlllin'g member ISthereo'f being maintained in'the normal or full-line position By this means it is possible to control the .roadside inductor either to produce an -efiective deenergiztionof the vehicle'carried translating devicev or relay to trip :the vehicle carried 3 apparatus, or to permit the yehiQIeJcarri'ed' a paratus to pass the roadside station'unaifectedso as .to prevent or inhibit the acter, another activating influence canjbe'pro- "duced in the vehicle'carried "conductors and apparatus bytne employmentof. a roadside circuit devoid of, any energy source. More particularly,

' have, le n'pirically found that. by' employing an inert orenergyless. roadside circuit of givencha ra'cteristicaa torque maybe produced in the relay {R whichis substantially greater than the normal torque. thereof due to the 'normal transmissionof flux from the primary coil P to the secondary coil S. 'This increase of torque in the ,relay'R may be employed for producing a third .rie'dapparatus, such as an indication in response to a caution roadside. condition, or-for effect- ;in'g air'esettin'g operation .of thetripped vehicle carried:apparatus'izr. .1 a. .i: .J.

These results I have found capable of being accomplished by the use of a tuned or resonant inert roadside circuit controlling"theroadside inductor, and tothese ends my invention contemplates the provision of a track or roadside inductormeans T embodying an inductor track coil t wound ona core I6 which preferably is laminated, the said coil t being controlled by a circuit d "devoid of anenergysource, which circuit is tuned or maderesonant by means of a condenser K connectedin series with the track coil t. The said circuit'is also provided with a switch member I! movable into the clear, caution and danger positions shown in Fig. 1 of the drawings by beingconrfec't'ed to a semaphore, signalling appara- .tus I8 or equivalent meansassociatedwith the insulated track sections or blocks 1-9 3.116.120 of a block signalling system. .When. the. vehicle carried inductor combination PS is positioned or moves overthe track inductor T when the, tuned or resonant circuit at is closed, an increaseover the normal .:torque of the relay R. is produced which is utilized to moventhe circuit controlling member 15 of the-relay to a third-position a indicated indotted lines in Fig. 1 of thedrawings. This increase of torque I believeis due to an increase in thedriving'E. M..F. in the secondary ,coil. S, such increase indriving E. F. being in turn due to a strong counter, magneto-motive ;cautionior danger track conditions, the inert core 16 of the track inductor 'l diverts or shunts the flux from the secondary as heretofore. described, andthereiore itwiil be-seen that the roadside circuit} d i is operative: to selectively diminish or increase the flux transmission from the primary coill? to,the secondary-coil S of the vehiclecarried inductormeans, the opening of the trackcircuit dcausing a' shunting or diversion; of fluxfrom the secondary, while the closing of said tuned. circuitzd causesa concentration or increase of flux through the secondary S, such increase operating the relay. RT-to its third position J'z.

-:Iri Fig. 3 of the'drawingaI-have shown a graph which :depicts" these characteristic operations of the'vehicle carried androadside inductors; In this graph the ordinates represent the torque effective on the relay R while the abscissae represent the movement of the vehicle inductor means over the track inductor, the latter beingshown onth'e graph.- Normally-a torque is produced'in the relay'R represented by the curve XX corresponding to the'position- 'x of l the relay armature T Under danger roadside conditions when the tuned circuit d is opened to produce the deenergization of the relay R, the torque curve drops and is-represented by, the-"curve XOYOX whenlthe train-carried andtrack inductoria are ,in co-operative relation.-When, however, thezvehicle .in-

ductorwcooperates withsthe track inductor on closed tuned circuit the torque of therelay increases' a's shownpby the curve XZX. This phenomenon maybe contrasted-with that produced .by an untuned track circuit, for with the use of an untuned trackcircuit-the torque of therelay slightly decreasesv when .the untuned track: cirfluencing the vehicle carried inductor means to respectively decrease and increase the energy transmission between the vehicle'coupled coils and to thereby produce respectively either one or the'other of said two operating conditions in the vehicle carried apparatus.

' 5. In combination, vehicle carried apparatus,

' a vehicle carried inductor means including inductively coupled coils operable for producing either of two different operations in said apparatus, one operation being efiected upon a reduction of the normal energystransmission between the inductively coupled coils; and a single roadside inductor cooperating with said vehicle carried inductor means, said roadside inductor embodying a circuit devoid of an energy source, said roadside inductor being operative on open circuit for influencing the'vehicle carried inductor means to produce said one of said two operations in said apparatus and operative on closed circuit for influencing the vehicle carried. inductor means either tolproduce the other of said two operations in said apparatus or to'permit the first of said op.- erations thereof to remain unafiected. v a

6. In combination, vehicle carried apparatus including an A. C. source of energy, a vehicle carried inductor means including inductively coupled coils energizable through said source of energy and operable for producing either of two different operations in said apparatus, one operation being eflectedupon'a reduction of the normal energy transmission between the inductively coupled coils; and a single roadside inductor cooperating with said Vehicle carried inductor means, said roadside inductor embodying a circuit devoid of an energy source, said roadside inductor being operative on open circuit for'influencing the vehicle carried inductor means to produce said one of said two operations in said apparatus and operative on closed circuit for influencing the vehicle carried inductor means either to produce the other said two operations in said apparatus or to permit the first of said operations thereof to remain unaffected. 7. In combination, vehicle carried apparatus including an A. C. source of energy, a vehicle carried inductor means energi'zable through said source of energy and operable for producing either of two different operations in said apparatus; and

a roadside inductor cooperating with said vehicle carried inductor means, saidv roadside inductor embodying a tuned or resonant circuit devoid of an energy source, said roadside inductor being operative on open circuit for influencing the Vehicle carried inductor means to produce one of said two operations in said apparatus andoperative on closed circuit foriniiuencing the vehicle carried inductor means either to produce the other of said two operations in said apparatus or to permit the first of said operations thereof to remain unaffected.

8. An induction train control system comprising vehicle carried apparatus, a vehicle carried inductor means including'an energy transmitting element and an energy receiving element coupled together and operative for tripping and resetting the vehicle carried apparatus, the tripping being effected upon a; reduction of transmission of energy between the coupled elements, and road,-

side inductor means cooperatingwith the vehicle carried inductor means and comprising aninductor element cooperable inductively with the vehicle carried coupled elements and circuit means devoid of any energy source governing said inductor element for selectively producing therein tripping and resetting indications to selectively effect tripping and resetting operations of the vehicle carried inductor means. w

'9. An induction train control system comprising a controlling relay, a vehicle carried inductor means including anenergy transmitting element and anenergy receiving element coupled together, said energy receiving element being connected to saidcontrolling relay and said elements being operative for tripping and vresetting the controlling relay, the tripping being efiected by substantially deenergizing said relay, and. roadside inductor means cooperating with the vehicle carried inductor means and comprising a single inductor element cooperable inductively with the vehicle carried coupled elements and circuit means devoid of an energy source governing said single inductor element for selectively producing therein tripping and resetting indications to selectively eiTect tripping and. resetting operations of the vehicle carried inductor means.

10. An induction train control system comprising vehicle carried apparatus, a vehicle carried inductor means includingan energy transmitting element and an energy receiving element coupled together and operative for tripping and resetting the vehicle apparatus, a roadside inductor means cooperating with the vehicle carried inductor means and comprising a single inductor element cooperable inductively withvthe vehicle carried coupled elements and capable when in effectively open circuit of reducing the transmission of energy from said energy transmitting element to said energy receiving element to produce a tripping operation in said vehicle carried apparatus, and circuit means devoid of an energy source governing the said inductor element for producing therein a resetting indication transmittable to for effecting a resetting operation of said vehicle carried inductor means.

11. An induction train control system comprising a governing relay, a vehicle" carried inductor means including an energy transmitting element and an energy receiving element coupled together, said energy receiving element being connected to said controlling relay and said elements being operative for tripping and resetting the said relay, a roadside inductor means cooperating with the vehicle carried inductor means and comprisingan inductor element cooperable inductively with the vehicle carried coupled elements and capable when in effectively open circuit of influencing said vehicle carried inductor means to produce a tripping deenergization of said relay, and circuit means devoid of an energy source governing the said roadside-inductor element for producing therein a condition transmittable to said vehicle carried inductor means for effecting a resetting operation of said relay.

12'. In combination, vehicle carried apparatus including an A. C. source of energyfa vehicle carried inductor means comprising inductively coupled coils, the primary coil of which is connectedto said A. C. source and the secondary coil of which is connected to said apparatus, and roadside inductor means cooperating with said vehicle carried inductor means, said roadside inductor means embodying a coil and a circuit devoid of an energy source, said roadside circuit being operative to selectively diminish or increase the normal energy transmission from the primary coil to the secondary coil of the vehicle carried inductor means to effect either of a plurality of operations in said vehicle carried apparatus.

13. In combination, vehicle carried apparatus including an A. C. source of energy, a vehicle car'- ried inductor means comprising inductively coupled coils, *the primary coil? of .whichzis' connected to, said A. C. source a'ndthe secondary coil 5 of which is connected to. said apparatus, androa'dside inductor means: cooperating-with: said vehicle 2 carriedinductor g means, and operative to selectively diminish orincrease the'normal energyv transmission from the prim'aryicoil to the nected to Said'A.C. source, androadside inductor I means cooperating with said vehicle'carried inductor means, and operative to selectively diminiSh'vOI, increase the normal "energy transmission 1 fromtheprimary coilto the,v secondary coil of the vehicle carriedinductormeanspw 15. In combination, vehicle-carried apparatus Y including an A. C. source of. energy,a vehicle carried inductor means'comprising inductively cou-= "g pledcoilathe primary coilg-of which is connected .to: said A. Cssource and the secondary coil of which is connected to said apparatus, and roadside; inductor means cooperating with said vehicle carried inductor means and operative to selectively diminish or increase the normal ,energy transmission from the-primary coil'lto the secondary coil of,the vehiclecarried inductor means to-efiecteither atripping or resetting operparatus.:q., a m

16. In; combination, vehicle carried apparatus including an A. C. source of energy, a vehicle'car of whichis connected to said apparatusand roadside; inductor means cooperating with said vehicle carried inductor-means, said roadside inductor means embodying a single coil and'a circuitdevoid' of an energy source, said roadside circuit'being operative when open andclosed to respectively diminish and increasethe normal energytransmission from the primaryz coil to thesecondary coil of the vehicle carried inductor .n1eans v Z H j I v 17 In; combination, vehicle carried apparatus including an A. C. sourceof energy; a, vehicle carried 1 inductor means 2 comprising inductively coupled coils-the primary coil of which is. con-:

. nectedto said A. C, source and the secondary coil of which is connected, to said apparatus, and

roadside inductor meanscooperating with said vehicle carried inductor means, said roadside inductor means embodying a single :coil and a resoopen and closed to respectively dirninish andincrease the normal energytransmission fromlthe carried inductor means; g 1 8. In combination; vehiclecarried apparatus including an A; C! source ofenergy a vehicle carried inductor means comprising inductively a coupled'coils; the primary coil of which is con-" 7 "ne ct ed to said A. C; source and thesecondary coil ofwhich is connected to. said apparatus, and

75; resonant circuit devoid of an energy source, said carried inductor means. to effect either .eavttipe ation respectively-in said vehicle carried aptive on open and on closed circuit for afiectingthe.

vin said'relay; Y

nant circuit devoid of an energysource saidv resonant roadside circuit being a operative when primary 'coilto' the secondary coil of. the vehicle the A.' C..renergy sourceaandathe se'condary coil,

ofwhichisconnectedto an element ofv saidrelay; r

resonant roadside circuit? being operativeiiwhen open. and closed to; respectively diminish and; in-' crease thenormalenergyltransmission Iromthe j primary'coil-to the secondarmcoil of thefvehicle r ping or' resetting operations respectively in said vehicle carried apparatus. -15 1 19; In combination, avehicle carried apparatus including an .-A. C. energy source "and; a; relay; za vehicle carried inductor means {including induce" tively coupled coils energized from saidener'gy source foroperatingsaid relayygand =a-Ioadside' inductor cooperating with the vehicle carried in-" ductorgmea-ns, said-roadside inductor embodying a tuned .orresonant circuit .devoid of an energy source and operative on closed circuit for aseea; ing .the vehicle carried. inductor means :to pr due an increase of torque in said'rel ay;

20. Incon bination, vehiclecarried apparatus includingjalrrelay a vehicle' carried inductor riedinductor means to produce respectively a decrease and anincrease of. torque. in said relay/w 21.: In combination; vehicle carried apparatus including an- A. CQene'rgy source and a relay, a vehicle carried inductor: means including Jinduc-, tively coupled :coils energized. from *saidgenergy source for operating, jsaid, relay and a roadside inductor. having v a .singlefiux path cooperating with the vehicle carriedlinductor means; said roadside inductor embodying aicircuit. devoid of an energy source, said-{roadside inductor being operative onopen and oniclosed circuit for :aiiEect-e I ing, the, vehicle carriedinducton means to, pro-= duce respectively a decrease and fangincrease of torque 'in said relays p v 1" a: wire" 22; Inlcombination; vehicle .carried apparatus, including; a relay,i a! vehicle carried inductor I means=for operating'said relay;.and-=a roadside inductor. cooperating with the; ,vehicle ,carried inductor means, said roadside inductor'embodye ing a tuned-or resonant'circuit devoidofansena ergy source, said roadside inductor being foperavehicle carried inductor r'neans. to produce irespectively a decrease" and an increase of. torque 23; In combination, vehicle carried apparatus including. an A. C. sourceofrenergy. and arelay; vehicle carried inductively coupledcoils, .-the:-pri.-: mary coil of which is connected :to the A..C.'en+,;

ergy source and thesccOndary: coil "of which-zi'su connected tosaid'relay;iandlaroadsideinductor; j

cooperating with the vehicle carried inductively coupled coils,.said roadside inductorpcomprisinga,coil*anda circuit therefor devoid of an energy. source and operative when said energyless circuit.

is closedi'and. opened for influencing, the, vehicle carriedinductor coils to producearespectivelyian increase and decrease of the; normal, operativev torque iinsaidrelay; 1 1

.- 24'.-:In combination; vehicle A carried i apparatus,

including an A. Cksource-ofenergy an'd a twoy'element relay; vehicle carried inductively coupled* coils the primary .7 coil ofj which is connected to the-said coils being coupledso that the secondarycoilis normally energized from said primarycoil and a roadside inductor cooperating With thew 75*; i 1 a I means for operating said. relay; anda roadside normally producing a given condition in said relay hicle carried inductively'coupled coils, said roadside inductor comprising a coil and a tuned or resonant circuit therefor devoid of. an energy source and operative whensaid energyless circuit is closed for influencing the vehicle carried inductor coils to produce an operating torque in said relay.

- 25. In combination, vehicle carried apparatus including an A. C. source of energy and a two element relay, vehicle carried inductively coupled coils, the'primar'y coil of which is connected to anelement of :said relay, the otheraelement of saidtrelay being connected to the A. C; energy source; the said coils'being coupled so that the secondary coil is normally energized from said primary coil, and a roadside inductor cooperating with the vehicle carried'inductively coupled coils,

said roadside inductor comprising a coil and a circuit therefor devoid of an energy source and operative when said energyless circuit isclosed for influencing the vehicle carried inductor coils toproduce an operating torque in said relay.

26. In combination, vehicle carried apparatus including'an A. C. energy source and a relay, vehicle carried inductively coupled coils the primary coil of which is connected to the A; C. source and the secondary coil of which is connected to said a including a source of energy and a relay means,

a vehicle carried inductor including inductively coupled coils the primary of which is connected to said energy source and the secondary of which is connected to said relay means, the coupled coils normally producing a given persisting energized condition in said relay means; anda single cooperating roadside inductor including a coil and an energyless circuit therefor operative when open and closed for influencing the vehicle carried coupled coils to produce respectively either a deenergizing condition or difierent energizing conditions in said relay means.'

28. 'In combination, vehicle carried apparatus including a source or energy and a three position relay means, a vehicle carried inductor including inductively coupled coils the primary or which is connected to said enery source and the secondary of which is connected to said relay means, the coupled coils normally producing a given position in said relay means; and a cooperating roadside inductor including a coil and an energyless tuned or resonant, circuit therefor selectively operative to influencesaid vehicle carried coupled coils to produce either of the other two positions in said relay means.

29.' In combination, vehicle carried apparatus including a source of energy and a relay means, a vehicle carried'inductor including inductively coupled coils the primary of which is connected to said energy source and the secondary of which is connected to said relay means, the coupled coils means; and a cooperating roadside inductor including a coil and an energyless circuit therefor selectively operative to influence said vehicle carried coupled coils to produce either of two other conditions in said relay means,- said relay means having a field connected to said source of energy v and having an armature connected to the secondary inductor coil.

30. In combination, vehicle carried apparatus comprising a source of energy and a relay having field and armature coils, inductor means including inductively coupled coils the primary of which is connected to said source of energy and the secondary of'which is connected to the armature coil of said relay, the said coils being coupled so that the secondary is normally energized from said primary, the field coil of said relay being connected to said energy source, and means for improving the phase relationship between. the currents in said relay field and armature coils, said means comprising resistance and capacitance arranged in circuit with said field coil.

-31. In combination, vehicle carried apparatus including a source of energy and a relay, vehicle carried inductively coupled coils the primary of which is connected to said energy source and the secondaryof which is connected to said relay, the said coils being coupled so that the secondary is normally energized from said'primary, and means for determining the phase relationship between the current and voltage eifective on said relay; and a single cooperating roadside inductor including an energyless tuned circuit operative when closed for affecting the vehicle carried coupled coils to produce an actuation of said relay.-' l

32. In combination, vehicle carried apparatus including a source of energy and a two element relay, vehicle carried inductively coupled coils the primary of which is connected to said energy source and the secondary of which is connected to said relay, the said coils being coupled so that the secondary is normally energized from said primary, and means for improving the phase relationship-between the currents in the elements of said relay; and a cooperating roadside inductor including an energyless tuned circuit operative when closed for affecting the vehicle carried coupled coils to produce an actuation of said relay; 7

33.-In combination, vehicle carried apparatus including a source of energy and a relay having field and armature coils, vehicle carried inductively coupled coils the primary of which isconnected to said energy source and the secondary of which is connected to the armature coil of said relay, the said coils being coupled so that the alternating current, an associated signal-receiving circuit, a train-carriedinductor or unit for transmitting current, to and receiving current fromfthe wayside, means included in said unit whereby thedirect'effect of the source upon; the receiving circuitis altered as compared'with the effect thereon of said source whensubjected to the influence'of a wayside circuit, together with a wayside circuitadapted to inductively control the train-carried receiving circuit'in accordance with signal indications, r

THEODORE Boone.-

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