US2357235A

US2357235A - Coded railway signaling apparatus

Info

Publication number: US2357235A
Application number: US516363A
Authority: US
Inventors: Arthur L Jerome
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1943-12-31
Filing date: 1943-12-31
Publication date: 1944-08-29
Anticipated expiration: 1961-08-29

Description

A. L. JEROME CODED RAILWAY SIGNALING APPARATUS Aug. 29, 1944.

' Filed Deo. 31, 1943 Patented Aug. 29, 1944 UNITED STATES cierres" Arthur L. Jerome, Edgewood,- Pa;, assignor to The"l Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania,

Agp*plicacmn:Decemberv 31, 191132 seriali@NeiA sieg-36e 11 claims. (cl. 24a-ssi.-

My inventionrelates to railway signaling ap'- paratus and particularly to improved apparatus of the type shown application for Letters Patent of the United States, Serial No. 512,723, led December 3,11943, by Crawford E.- Staples; for use in a single track stretch to supply coded alternating currentv c'absi'gnal-controlenergy to theV rails of. track sections equipped? wthtrack cir'' cuits employing-steady energy.

In application for Letters Patent ofthe Unitedf States, Serial No. 412,279,0f J ames-J Van Horn, now United States Patent No. 2,344,333; dated March '14, 1944; there is shown a signaling system adapted for use in" singlev track stretches over which traffic moves'in both' directions. Thissystem employs coded energy to control traffic, and most of the track sections are provided with track circuitsl employing coded' energy, but in some cases, such as the approach sections to a'high-4 way crossing, the track sections are providedwith track circuits employing steady" energy, Whilel the coded tr'ac governingI energy is transmitted around these-sectionsv by means of al lineA circuit. Y

In track stretches through which are operatedl locomotives equipped vwith cabl signal apparatus, it is necessary to provide 'means tosupply codedv alternating current of appropriate' code frequencyto the railsof the track sectionsequi-pped with track circuits employing steady energy;

In the above-identified application of Craw-f ford E. Staples, there is shown. means employing two coding relays, onev for each direction of trafc, for supplyingv coded alternating current to the rails of the approach sectionsv to a highwaycrossing, While these coding relays areV operated by codedenergy supplied to the line circuit extending. around the approach sections.

It is an object of this invention toprovide im'- proved alternating'current supply means of theV type described and employing a single coding4 re` lay which serves for both directions of traffic.

A further object ofthe invention is to provide" improved'means ofthe type described which employs a coding relay responsive vto energy of one polarity only ar'idis reversibly connectedl across" the linewires `so as to beoperated by energy supj plied to the line Wires even though energy of one polarity is supplied to the line Wires when traic is established for one direction, and energy of the other polarity'is suppliedY to theline wires when traiiic is established for the other direc- -I A. Y I e Another vobject' 'oflthe' invention mito-provideimproved means ofthe type described' which' emated by energy" supplied tothe 'line wres at: one

end thereof; and so that' on movement trapani-1 through the trackgstretch inthe opposite direc/4f' tion the coding relayjisI connected across-thai rife'- Wires so astoy be operated'4 by energy suppliedf to the line wires'at' the` otherle'ridjthereof.

Other oloje'cts ofthe-invention andffeatlires-of novelty will'be apparent fromY thefoll'ovv'ingde sci'iption` takenvv in' connection' vvift-ii the `f accoii panying drawing;

I shall describe twojform'sf of railway signalig apparatus embodying my' invention vend shall' then point out' the novel features: thereof in" claims.` In' practCinglny-"invetir, I'pvide ai cbtli`r'1'-g-g relay at' the highwayv^` intersection arid-provide' means governedv by the approach sectiontr`acl` frelays for v reversiblyconnecting the coding relay across the line-Wires extendin'glaroundthe ap# proach sections; In additio'r, I providevrne governed by the'T approachsecl'ior'i' tra'ck-v rel for controlling the codedU altelnatig curefl't' supplied on operation of the'codingirelayso'fthat this energy is supplied-tothe proper track trans-4 formers on movement of avv trainthroughltle' track stretch ,in either direction'.-

In the drawing, the single'gre's a'di-agrarf: showing a. stretch of railway track'feduippedwith' one form' of signaling? apparatus embodf'ingniy invention.

vReferring to thev drawing, there is? showif therein a vstretch of single track 'railroad through which are operated in both' directions locorol' tives; equipped withY cab' signal-'apparatus r's'po'n sive to flow of coded alternating! current inthe 451 track rails. The construction-and operation of the locomotive v'cab signalapparatus fis" not apartf` oi?l thisinvention and'the' locomotive eqliiprhe'ntv mayj vloe *constructed asi shown inLetters Patenti' ofthe United States No. 1,986i6'779`ttlfb-V7. The"'trackf stretch shownin'- the drawingv is" a* part of' a singler tracl stretch equipped W1 f trafc governing signaling-apparatusof theft'ypef shownv application', Sel-iai NO'.- 412;2v79f V0T" James J. Van Horn. In'tlie system shown inf-fthe? inthe" track stretch, except for' the portions ofthe" tack'j stretch where shortV detector'tracki'circuits' 'are required, is equippedwith two' trackcirciiitsg^v drieI for each direction of train@ Means aref'prvidl" edto` attimes supply steady eriergyfto 'either end l of the track stretch, while the track circuits are 'arranged so that when the track stretch is vacant this steady energy is cascaded from one section to another throughout the track stretch to energize traffic locking means at the other end of the' stretch and thus permit the direction of tralc to be changed. In addition, there are means at each end of the track stretch eiective after the stretch has been conditioned for either direction of traffic to supply coded energy to thesection at the exit end of the track stretch, and the track circuit apparatus for each section is arranged sothat this coded energy is cascaded from one section to another to the entrance end of the track stretch to control the signal at the entrance end of the stretch.

As shown in Fig. 4 of the Van Horn application,v

where a highway crossing is encountered, track sections employing steady energy track circuits are provided on either side of the intersection to control the crossing signals, while a line circuit is provided to carry around these sections the steady and codedenergy employed in the rest of the track stretch.

. The portion of the track stretch shown in the drawingV of this application includes an inter-` section with a highway and this crossing is protected by crossing'signals XS, while thetrack stretch is divided into suitable track sections for` cations Ymay be arranged as shown in the VanV Horn application. In Aorder to simplify the disclosure and facilitate-understanding of my invention, only the equipment Yfor the approach sections and the adjacent ends of the adjoining sections has been shown in the drawing.

The rails .l and 2l ofthe track stretch are divided `by insulated joints 3 into a number of track sections each of which is identified by the reference character T with a distinguishing preiix which also identies the apparatus associated with that section.

To facilitate description of the equipment and its operation, it will be assumed that the righthand end of the track stretch is east and that the left-hand end of the track stretch is west so that train movements from left to right are eastbound and train` movements from right to left are westbound.

The intermediate track section 'ICT is a short section which includes the highway intersection, and this section has at one side the eastbound approach section 'I'BT, and at the other side the westbound approach sectionlDTL The track relays TBTR and 'IDTR of theapproach sections cooperatewith track relay ICTR of the intermediate section 'ICT to control directional stick relays WSR and ESR and the crossing signal control relay XR. However, the invention is no-t limited -to the use of this form of crossing signal control` apparatus landan interlocking re- The approach sections andthe intermediate sections are provided with track circuits employing steady energy. Each of these track circuits includes a track battery connected across the section rails at one end of the track section and a track relay, designated TR with an appropriate prefix, connected across the section rails at the other end of the section.

Each track section in the track stretch is provided with a track transformer at each end of the track section. These track transformers are designated TT with an appropriate prefix to indicate the track section with which the transformer is associated and the end of the section at which it is located.

The track transformers at the ends of sections lBT, 'ICT and IDT at which the track batteries are located have their secondary windings connected in series with the track batteries,

while these secondary windings are of relatively low resistance so as not to unduly reduce the supply of energy from the batteries to the section rails.

. The track transformers located at the track relay ends of the sections have their secondary windings connected in multiple with the track relays, While resistors are included in series with the track transformer secondary windings to restrict llow of track circuit energy in these windings. The track relay windings have such high impedance to alternating currentthat little energy from the track transformers flows in the relay windings.

As explained in the application of James J. Van Horn, each of the track sections lAT and IET is provided with two track circuits,l one for each direction of traic. each of these track sections includes a code following track relay at one end 0f the track section and a track battery at the other end of the section,A while at Ieach end of the section there is a coding relay CTM having contacts controlling connection of the associated track battery and track relay with the section rails.

The equipment at the highway crossingv vincludes a coding relay XC'IM which operates as hereinafter explained to cause coded alternating current to besupplied to section TCT, and to section 'FBT or IDT.

The coding relays XCTM, 'IEACTM and TWECTM are of the magnetically biased type the contacts of which normally'occupy their released position and are picked up only when energy ilows through the relay winding in a given' direction. As shown in the drawing, the

relay XCTM is arranged so that its contact tacts pickup only when the positive terminalv of the source is connected to the right-hand terminal of the relay winding.

The relays and 'other equipment except the track. relays are supplied from suitable sources ofdirect current, such as storage batteries, not

shown, located at appropriate points in the track stretch. The positive and negative terminals of these sources are designated B and C, respec- Y tively, lin the drawing. Y

The alternating current supplied to the track transformers may be supplied from any suitable source, not shown, the terminals of which are= designated BX and CX in the drawing.

. The equipment 4is shown in the condition Each track circuit forv wgss y l 3" which it assumes when the trackstretch-is val cant and steadyl energy is suppliedv at the east endof the track stretch. As explained in the Van-Horn application, steady energy supplied at the Veast endy of,` the track stretch isv cascaded from one` track section to another to the West end of'the' track stretch to energize tralic locking mea-ns at thatf point.

As steady energy isv supplied to the' east endl ofv section TET, this energy feeds over back contacts of coding relayY 'IWECTNI" and holds the contacts of track relayv 'IEETR picked up so that its contacts I andv I I'connect line Wires I4 an'df I5 to the terminals of a source of direct current. Accordingly, energy is supplied from terminal B over contact II, wire I 5, front contact I I3 ofv track relay 'ID'IR, front contact I'l of track relay 'ICTR, front contact I8 of track re` lay lBTR, back contact 2| of track relay lwATR, Winding of coding relay 'IEACTM from right to left, back contact 2'0 of track relay TWATR, line Wire I4, front contact 22 of relay 'IBTR, front contact 23 of relay 'ICTR, front contact 24' of rel'ay 'ID'.IR, and front contact IIJ of track relay TEETR to terminal C. The direction of flow of energy through the Winding of coding relay 'IEACTM is proper to pick up the relay contacts 25 and 25 and they are picked up to connect track battery 'IEATB and track transformer lEATT across the rails of section 'IAT and to disconnect the track relay IWATR from the section rails. Accordingly, steady energy is supplied from the battery IEATB to the railsV of section IAT and this energy picks up the track. relay not shown at the Westend of this section and causes the supply of steady energy to be repeated throughout the other track sections to the West end of the track stretch.

As the track stretch is vacant, the track relays 'IBTR, ICTR and 'IDTR are picked up so energy is supplied to relay XR overthe circuit including front contact 21 of relay 'ICTR, frontv contact 28 of relay 'IDTR, and front Contact 29 of relay 'IBTR, so contact'30 of relay XR is picked up to prevent operation of the crossing signals i XS At this time, relays WSR and ESR are released, While relay XCTM is deenergized and its contact 32 is released.

If it is desired to permit a Westbound train to pass through the track stretch, means, not shown, at the right-hand oreast end of the trackV stretch are operated to permit clearing of the Westbound signal .at that point and to cut 01T the supply of steady energy toY the east end ofthe stretch, when the supply of steady energy to the stretch is cut oi, the track relay for each section releases and cuts off the supply of steady energy to the adjoining-section so the supply of steady energy is cut off from the Various sections in succession throughout the track stretch, While the contacts of the coding relays are released and connect'the track relays across the sectionrails.

At this time, therefore, relay 'IEETR releases and cuts off the suppl-y of steady energy to the line Wires I 4 and 'I5 so relay 'IEACTM releases and cuts off thev supply ofenergy from battery "IEATB and transformer 'IEATT to the rails of section 'IAT and connects track relay 'IWA'IRy across the section rails.

When the supply of steadyenergy at the westA of suitable codefrequency, such als-75l orf-180 codeifrequency, to besuppliedl to the-west end fof" the track stretch.

On the supplyA of coded energy to the West end vof the track stretch,l codedfenergy is'cascaded through the successivetrack sections to section 'IAT and coded-energy is supplied over back contacts 25 and 26 of relay 'IEACTM to track relay 'IWA'IRv Accordingly, track relayv TWATR follovvsv code, andduring the picked-up periods of the relay its contacts 20 and 2I-connect wires I4 and I5 across a source of direct current with wire I4 connected to the positive terminal of the source. Energy su-ppliedto theline Wire feedsl over back contacts- IU'- and I-I of relay 'IEETR and through thewinding of coding relay 'IWECTMfso that it operates to cause coded energyto be supplied from track batteryA IWETBy and track transformer TWET'I. to therails ofsection IET, While the track cir-- cuit apparatus, not shown, at the east end of section IET causes coded' energy to be supplied v to` the-adjoining section, l

It is to be observed that when energy is sup pliedl to line Wires I4 and I5? by operation of relayv IEETR, the positive terminal ofthe sourceis connected to wire I5; and the energy supplied' tothe line- Wires is ofthe polarity effectivetc 0perate coding relay 'IEACTM, While- When energy' is supplied to line wires I4 and I5 by operation- Ofrelay 1WATR, the positive terminal of the source is connected to wire I4 and the'energyJ supplied tothe linewires'is of the polarity effective/to operate coding relayV lWEcTM. The'use of diierent polaritiesI of energyin the line circuit for diierent directions-of traic is advantageous, as it preventsV improper operation of the coding relays, if the track relay contacts over'- lap.

For example, if the front and back contacts'ofl track relay 'IEETR a-reA out of adjustment so' that movable contacts I il and IIY both engage their front contacts before being disengaged from'Y their back contacts, energy will be. supplied from the source at that point to the coding relay- 'IWEGTM, but the polarity of'this energy-iss'uch that-it Will not pick up the contacts of' relayenergy'supplied theretorin the event of overla-p'` ping contacts on the track relaylWATR.A

When a Westbound train enters section 'IET, the cab signal apparatus on the locomotive is f operatedv by coded alternating current. supplied to the section rails as a result of operation ofi coding relay 'IWECTM.

When the train advances into section 'IDT,` track relay IDTR releases and its contacts I 6 andv 24 interrupt thecircuits of line Wires I5 and'4 I4 to thereby cut ol the'suppl'y of energy to coding relay IWECIMso that it ceases to supply en ergyl to the rails of section 'IET and remains re'- I leased so that' track relay 'IEETR is connected f acrossthe section rails.

On release of relay- 'IDTR,y the coding relay XCTM is connected across the line wires I4 and I5 so as to be operated by coded energy supplied to these wires as a result of coding operation ofl relay IWATR. At this time, energy is supplied to relay XCTM over the circuit which is traced Vfrom terminal B of the source over front contact" Zgof relay 'IWATR, wire I 4, front contacten,` ofu relayIBTR, front contact23 of. relay 7CTR,. back contact24=of relay-ID-IR,l Winding. of relay'- polarity ofthe energy supplied to relay XC'I'M is proper to operate the relay and the relay contact 32 operates at the rate determined by the rate of operation of relay TWATR.

On coding operation of relay XCTM, codedaly ternating current is supplied from back contact 43 of relay ESR to the transformer TWCTT and also over front contact 45, of relay TCTR to the transformerv TWDTT so that coded alternating current is supplied to the rails of section TDT to operate the locomotive cab signal apparatus while the locomotive is in section TDT. Prior to picking up of relay WSR coded alternating current is also supplied over its back contact 44 to transformers TEBTT and TECTT.

In addition, on release of track relay TDTR, its contact 28 interrupts the circuit of relay XR so that contact 30 of relay XR releases and establishes the circuit of the crossing signals XS and they operate to Warn users of the highway of the approach of the train.

On release of track relay TDTR, a pick-up circuit is established for relay WSR and includes front contact 34 of track relay TBTR, back contact 35 of track relay TDTR, and back contact 36 of relay ESR.

Accordingly, relay WSR picks up and its contact 44 cuts off the supply of coded alternating current to the transformers TEBTT and TECTT, While contacts 38 and 4I of relay WSR connect relayXCTM across line Wires I4 and I5 at a point intermediate the contacts of relays TBTR and TCTR in these line Wires to thereby continue operation of relay XCTM after the train advances into section TCT and track relay TCTR releases. At this time, the left-hand terminal of the Winding of relay XCTM is connected over back contact 3T of relay ESR and front contact 38 of relay WSR to the Wire I4, While the other terminal of the Winding of relay XCTM is connected over back contact 40 of relay .ESR and front contact 4I of relay WSR to Wire I5 so the energy supplied from the line Wires is of the proper polarity to operate the relay XCTM.

At this time, coded alternating current continues to be supplied over back contact 43 of relay ESR to the transformers TWCTT and TWDTT, that is, to the transformers appropriate for movement of a westbound train through the track stretch.

From the foregoing, it will be seen that when a westbound train enters section TDT, relay XR releases to initiate operation of the crossing sig'- nals, while relay XCTM is connected across the wires I4 and I5 so as to be operated by coded energy supplied to these line Wires over the front contacts of relay TWATR and operates to supply coded alternating current to the track transformers and thus to the track rails to operate the locomotive cab signal equipment.

When the train advances into section TCT,

track relay TCTR releases and its contact 45 in-v terrupts the circuit for supplying coded alternating current to thek track transformer TWDTT, while energy continues to be supplied to trans- In addi-l tion, When a westbound train enters section TDT energy supplied to these Wires over contacts of relay TWATR from reaching relay TWECTM on picking up of relay TDTR. On release of relay TCTR, the originally traced circuit for relay l XCTM is interrupted, but this relay continues to be supplied with coded energy from line Wires I4 and I5 over the connections established by relay WSR.

In addition, on release of relay TCTR, a stick circuit is established for relay WSR and includes back contact 2T of relay TCTR, and front contact 46 of relay WSR. v

When the train advances into section TBT, the cab signal apparatus on the locomotive is operated by coded alternating current supplied to the rails of section TBT from transformer TWBTT, while coded energy is supplied to the transformer TWBTT over the circuit including contact 4T of track relay TWATR.

When the train enters section TBT, track relay TBTR releases and its contacts I8 and 22v interrupt line Wires I5 and I4 so that coded energy is no longer supplied to coding relay XCTM and the contact 32 of this relay remains released and energy is no longer supplied to either track transformer TWCTT or TWDTT. Release of contacts I8 and 22 also prevents energy supplied to the line wires I4 and I5 on picking up of track relay TEETR from feeding over lback contacts of track v relay TWATR to coding relay TEACTM with resultant interruption of the coding operation of track relay TWATR.

When the train advances into section TAT, the track relay TWATR ceases to follow code and its contacts remain released to connect line Wires I4 and I5 to coding relay TEACTM, while contact 4T of relay TWATR interrupts the supply of energy to track transformer TWBTT.

As explained in the Van Horn application, steady energy may be supplied to the track stretch behind the train,`and this steady energy will be cascaded throughout the track stretch as each track section is vacated, but only after an impulse of coded energy has been supplied over the section rails. Accordingly, when section TET is vacated, relay TEETR remains released and connects line Wires I4 and I5 to relay TWECTM.

When the train vacatesl section TDT, track relay TDTR picks up and energy is supplied to relay WSR over the stick circuit which includes front contact 35 of relay TDTR, back contact 34 of relay TBTR, and front contact 48 of relay WSR. The energy supplied to relay WSR over this circuit keeps relay WSR picked up after section TCT is vacated and relay TCTR picks up and its contact 2T interrupts the previously traced stick circuit for relay WSR.

When section TCT is vacated and track relay TCTR picks up, energy is supplied to relay XR over the circuit Which includes vfront contact 2T of relay TCTR, front contact 28 of relay TDTR, and front contact 50 cf relay WSR, so relay XR picks up to discontinue operation of the crossing signals XS.

When the train vacates section TBT, track relay TBTR picks up and its 'contact 34 interrupts the stick circuit for relay WSR, While its contact 29 completes the circuit including front contact 28 of relay TDTR and front contact 2T of relay Signals XS. On release Vofsrelay WSRyits contacts 46 4and vI8 a'dditionallyinterrupt the stick circuits for the relay, While its contacts 4I and 38 interrupt the crcuit'of coding relay XCTM, and its .contact144 establishes the ycircuit over Which .coded-alternating current -is supplied .to transformers IECTTJandLTIEBIT onoperation of coding relay XCTM.

Whentrack relay 'IB'lI'Rpicksiun its `contacts I8 and 22 completethe. circuit of line yWires I5 and I4 so thatwhenythe .train vacates section .'IAT and coded .energy .supplied over the rails of that section picks up `relay 1-WATR, an impulse of energy is .supplied .over the line Vwires If4 and I5 to relay 'IWECTMrandLit causesan impulse of energy to be supplied vto the trails of section IET. This energy may `cause -the Aequipment at the right-hand -end of section .IET to operate to supply steady energ-y;to .the rails of section'IET, and this energy feedsy over .back contacts of relay IWECI-'M `and 'picks '..up .the :contacts of relay ,IEEER `andthusxcauses .steady energy to be supplied .toxthe line Wires 'I4 Yand I5@ This energy feeds to relay .IEACTMand causes steady energy to .be supplied to the :railsof `section IAT.

If, after .the Westbound trains vacate the track stretch, the .steadyenergy supplied at the east end of the'track stretch is cut off and coded energy substituted therefor, this coded energy Wllbe cascaded throughout the track stretch to clear the signal at the west end-ofthe stretch and vpermit an eastbound train Ato enter the stretch.

.On the supply' of 'codedenergy `to the east end of section IET,-energy `feeds over -back contacts of coding relay I-WECTM totraok relay IEETR and operates' it so `that its contacts lIll 'and il I causefcoded energy to'be supplied to line wires I4 .and I5 with the result that coded energy is supplied to coding relay 'IEACTM and operates it lto supply coded energy to the rails of section 'IAT. In addition, when track relay Y'IEETR is operated by coded energy, coded alternating cur; rent is supplied over contact52 of relay 'IEETR to transformer IEDTT and therefrom to the-railso'f section IDT-'at the right-hand or exit end of the section.

AWhen an eastbound train enters section 1BT,

Y of relay XCTM is "connected over back contact I8 of relay IBTR to Wire-|15, while4 the other terminal of the-Windingof relay XCTM is connected over back contact 22 of relay 'IBT-R to Wire -I-4. On coding operation of relay l'IEE'IR, the positive terminal ofthe source is co-nnected to wire Iso the energy supplied to relay XCTM is of the proper polarity to operate the relay and its contact 32 operates to supply coded alternating cur,

rent to the track 'transformers at the highway intersection so that kcoded alternating current is supplied to therails of section 'IBT to operate the cab signal vapparatus on the locomotive While it is in that section.

In addition, on release Lof relay 'IB'IR,-energy is supplied to relay ESR-over the-circuitwhich includes front contact 35o-f relay .'IDTR, back contact 34 of relay 1BTR, and back contact 48 of relay WSR. Accordingly, the contacts of relay ESR pickup so that its contact `4`3fcutsfof the supply ofy coded alternating current to the transformers IWCTT and 'IWDIT from which energy is supplied to the rails of the track stretch 'on' movement of Westbound trains through the track stretch. At this time, coded alternating current continues to be supplied over back contact 44 of relay WSR to the transformers 'IECIT and lEBTT.

In addition, vvon picking up of relay ESR, its contacts '31 and -40 connect relay XCTM with the line WiresV I4 and I5 at a point intermediate the contacts of relays 'ICTR and 'ID'IR so that Irelay XCTM continues to rbe operated bycoded energy from line Wires I4 and I5 after the train enters section ICT and relay'lCTR releases. On picking up of relay ESR, the left-hand terminal of the Winding of .relay XCTM is connected over back contact 38 of relay WSR and front conta'ct 31 of relay ESR to Wire I5, While theother 'terminal of the winding of relay XCTM is connected over back contact/4I of relay `WSR and front contact 40 of relay ESR towire I4, and the enpolarity to operate the relay.

When the train enters-sectionTCT, track relay I 'ICTR releases and its contact 53 yinterrupts the circuit of track transformer 'IEBT'Ibut does not affect the circuit of /the'trans'former 'IECTTso that coded energy continues to be supplied to the rails of section 'ICT at the eXit end of the section to operate the locomotive cab signal apparatus while the locomotive 'is in secton'ICT.

On release of trackv relay 'ICTR, its contacts I1 and 23 additionally interrupt the circuitof line Wires I5 and I4, While its contact 2l establishes a stick circuit for relay ESR Which includes front contact of relay ESR.

When the train advances into section VIDT, the locomotive cab signal equipment is operated by coded alternating current supplied from transformer 'IED'IT to ythe rails Aof section 'IDT as a result rof operation of track relay 'IEE'I'R When the train enters section "IDT, track relay theline Wires I4 and I5, While contact 52 inter-` rupts the circuit of transformer 'IEDTT.

As explained in the application of J amesJ Van" Horn, steady energy may bey supplied'to'the trackstretch behind the train, and this steady energy is cascaded from one sectionvto another as the' train vacates each section and an impulse of coded energy is supplied over the section rails. Accordingly, when the train vacates vsection TAT, relay "IWATR remains released and its contacts 2D Vand Zliconnect line Wires I4 Aand I5 to the coding relay 'IEACTM.

When the train vacates section 'IBT, track re lay 1BTR picks up and'energy is supplied to relay ESR over the circuit including iront contact 34' of relay 1BTR, back contact '35 'of relay IDTR, andiront Contact 35 of relay `ESR,'and the energy supplied over this circuit keeps vrelayESR picked up afterrelay 'ICTR picks up to interruptvthe stick circuit which it controls for relay ESR.

When section ICT is vacated and track relay ICTR picks up, energy is supplied over front contact 21 of track relay 'IC'I'R, front contact 56 of relay ESR and front contact 29 of relay TBTR to relay XR so that contact 30 of relay XR picks up to discontinue operation of the crossing signals XS.

When the train vacates section 1DT, track relay 'IDRT picks up and its contact 35 completes the originally traced circuit for relay XR, and interrupts the stick circuit for relay ESR so the contacts of relay ESR release. In addition, contacts I6 and 24 of relay 'IDTR complete the circuits of linerwires I and I4 so that, when section 'IETisVacated andrrelay 'IEETR picks up, coded energy Will be supplied over the line wires, while when relay TWATR is\pickedup by vsteady energy supplied over the rails of section TAT, steady energy will be supplied over the line wires I4 and I5 to relay 'IWECTM and thus cause steady energy to be repeated throughout the track stretch.

From the foregoing, it will be seen that, when the track stretch is vacant, coded and steady traffic governing energy may be supplied between the track sections at the sides of the approach sections over the line Wires extending around the approach sections and that atV such times the coding relay XC'IM isl not connected with the line wires and does not interfere withv the coding relays at the ends of the line wires. It will be seen that, when the stretch-isA conditioned for movement of traflic in either direc-A tion, coded energy of appropriate code frequency is supplied to the line wires, While on entrance of a train into either approach section `the supply of energy over the line wires to the coding relay at the entrance end of the line wires'is curI off and the coding relay XCTM is connected across the linewires so as to be operated by the energy supplied to the exit end of the line wires. In addition, when the coding relay XCTM is being operated by coded energy, the energy supplied over the contact of the coding relay is supplied to the track transformers proper for the direction of trafiic in which the train is moving. As rsoon as the train vacates the track section which includes the highway crossing, operation of coding relay XCTM ceases, but supply of energy over the line Wires to the coding relays at the ends of the line circuit continues to be prevented until the train vacates both approach sections.

Although I have herein shown and described only one form of railway signaling apparatus embodying my invention, it is obvious that numerous 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. In a cab signal energy supply means for use in a stretch of railway track over which may move in either direction locomotives equipped with cab signal apparatus responsive to flow of coded alternating current in the track rails, the rails of said track stretch being divided by insulated joints into an intermediate section having a rst approach section at one side and a second approach section at the other side, said intermediate and approach sections each being provided.

with a track circuit including a track relay, said trackv stretch being equipped with traffic governing apparatus for conditioning the trackstretch for one direction of traflic or the other and including a pair of line wires substantially coeX- tensive with said approach sections and over which coded energy may be transmitted between the track sections at the ends of the approach sections remote from said intermediate section, said traiiic governing apparatus being effective when the stretch is conditioned to permit trafc to move from the first to the second approach section to cause coded energy to be supplied 'to said line wires at the end thereof remote from the rst section and being effective when the stretch isV conditioned to permit traiiic to move from the second to the first approach section to causecoded energy to be supplied to said line wires at the end thereof remote from the second section, in combination, a coding relay located adjacent said intermediate section and controlling the supply of coded alternating current to the rails of said intermediate section and to the rails of said approach sections at the ends thereof adjacent said intermediate section, means controlled by the track relays of said first approach and intermediate sections for supplying from the line Wires to said coding relay energy supplied to the line wires at the end thereof remote from said first approach section, and means controlled by the track relays of said second approach and intermediate sections for supplying from the line wires to said coding relay energy supplied to the line Wires at the end thereof remote from said second section.

2. In cab signal energy supply means for use in a stretch of railway track over which may move in either direction locomotives equipped with cab signal apparatus responsive to flow of coded alternating current in the track rails, the rails of said track stretch being divided by insulated joints into an intermediate section having a first approach section 'at one side and a sec-A ond approach section at the other side, said intermediate and approach sections each being provided with a track circuit including a track relay, said track stretch being equipped with traflic governing apparatus for conditioning the track stretch for one direction of traffic or the other and including a pain of line wires substantially coextensive with said approach sections and over which coded energy may be transmitted between the track sections at the ends of the approach sections remote from said intermediate section, said traiiic governingapparatus being effective when the stretch is conditioned to permit traffic to move from the first to the second approach section to cause coded energy to be supplied to said line Wires at the end thereof remote from the first section and being effective when the stretch is conditioned to permit traic to move from the second to the first approach section toA cause coded energy to be supplied to said line wires at the end thereof remote from the second section, in combination, a coding relay located adjacent said intermediate section and controlling the supply of coded alternating current to the rails of said intermediate section and to the rails of said approach sections at the ends thereof adjacent said intermediate section, means effective when said first approach or intermediate section is occupied by a train moving from said first to said second approach section to connect said coding relay across the line Wires so that the coding relay is operated by energy supplied to the line wires at the end thereof remote from the iirst approach section, and means effective' andi including a pair; of. line Wires substantiallyi coextensive vwith said approach-.sections and over.

when said second' approach orV intermediate `sec tion is occupied by a train movinggfrom saidy sec.- ond to said iirst approach section to connect said coding relay across said line wires so.v as to be: operated by energy suppliedlto the line wires. at the endthereof remote from the secondapproach section;

3;' In cab signa-l energy'supplymeans for use.`

` other and including a pair of line Wires substanf tially coextensiveA Withv said. approach sections and, over which coded; energy may kie-transmit,-A tedbetween the track'sections at the ends of theapproach sections remote `from saidy intermediate: section, said traic governing apparatus being effective'whenfthefstre-tch is conditioned to permitA traic to move from the first lto the second approach sectionto cause coded energy to be; sup.- plied to said line Wires at the end thereof: remote from the first section and being eiTective When theA stretchis conditioned tof permit traic' to move from the second tothe rst approach sec-- tion' to cause coded energy t0 be suppliedto said. line Wires; at. the end thereof remote from the. second section, incombination, a coding relay located adjacent said intermediate section and.y controlling the supply of coded.r alternating current to the rails of said intermediate sectionr and: to the railsrof saidapproach sections'Y at theA endsv thereofadjacent said-intermediate section; means eiective Whensaidrst approach or intermedi.` ate section is occupied by a train. moving from the rst to the second approach section temeon-Vv nect said coding relay acrossthe line Wiresso that the coding relay is operated by energy supplied to: the line Wires at the end-thereofremote. from the rst approach section While preventing flow. of energy between the portions of. the-'line wires. on opposite. sides of. the intermediate sec!-Y tion, and means. effective Whenv said,` second ap.- proach orv intermediatesectionV is occupied by aY train movin-g from the second to-the first ape.. proach section. to. connect` said coding relay across the. line wires. so that the.l coding relay isoperated by energy suppliedtol the. linefvvires.

at the end thereof remote from the second approach section While preventing now. of energyv betvveenthe portions-of the line Wires on opposite: sides of the interrrlediatesection.l

, 4. In cab signal. energy supply means for use in. a stretch of railway track, over which mayy move. in either direction locomotives equipped,l withy cab signal apparatus responsivev toiiow. of coded alternating current in thetrack rails, therails of. said track stretch being divided b-y insu lated joints into an intermediate, section having, a rst approach section at. one side and a4 second approach section at the other. side, said inter-e mediate and approach sections each being pro-y vided with atrack circuit including a. track relay, said track stretch being equipped Withv traflic. governing. apparatus for conditioningY the. track stretch for one direction of traino orgthe other.

10.; be suppliedto said;y line Wires at' the end .thereoft remote. from the irst-,sectionand being effective."

when theI stretch is conditioned to permit tra-Hic" 15, ity to be supplied. to said line wires at thel end;

rails of said intermediate sectionv and to the; rails.:

which coded energy may be transmitted between the tracksections at the ends of the approachY 5,4, sections; remote from said intermediate section,..

said traffic governingl apparatus being effective when thestretch is conditioned to permit traffic:

tol move from the first to the second approach sect-ionto cause coded' energy of one polarity to tot move from-,the second. to thevrst approachA sectionv to causefcoded energy of the other polarthereof remote'from the'secondfapproach section;v incombinatiom a coding relay located ad.-

jacent said intermediate section and controlling; l

the supply of coded alternating current to the of'saidapproach sectionsV at'. the` ends thereof ad.- jacentv saidintermediatel section, said coding re'- lay being responsive to energy of a given polarity only;` means effective when said iirst approach orv intermediate section, is occupied by a trainy v of remote from the first approach section, andi mov-nggfroinlthe first to the second approachv section toconnect said coding relay across the. linewiresrso that the. coding relay is operated by energy supplied'to the line Wires at the end theremeans.- effective When said second approach or intermediate section'is occupied by a train movl` `ing from-- the second to the first approach section-to; connect-said coding lrelay across the line..

Wires-softhat the coding relay is operated by energy supplied to -the line Wires at the end thereof. remote from the second section. Y

In cab signal energy' supply means for usein a., stretch of-- railway track over which may move;

4o; in eitherA direction locomotives equipped with cab signals apparatus. responsive to iloW of coded alternatingfcurrent inthe track rails, the railsof said track stretchbeing' dividedv by insulated joints'finto anintermediate section having a rst approach.sect'ion'at` one side and a second ap,-

proaclisectionat the other side, saidvintermedi.- ate. and approach sections each being providedwith atrack circuit including a track relay, saidl trackstretch being equipped with traffic governing apparatus for conditioning` the track stretch forone direction of. traic or thev other and in-- cluding a pair of line Wires substantially coextensive, with said approach sections and over which coded energy may be transmitted betweeny g. the track sections at the ends of the approach 65,;section to..` cause coded energy of the other polarity to be supplied to said. line wires at'the end` thereof remote from the second approach section, in combination, a coding relay located adjacent said intermedia-te section. and controllingv the 7D; supply of. coded alternating current to the rails of said intermediate section and to the rails oi said approach sections at the ends thereof adjacent saidV intermediate section, said coding relay being responsive to energy of agiven polarity on1ymeans effective when said rst approach or V intermediate section is occupied by a train moving from the rst to the second approach section to connect said coding relay across the line wires so that the coding relay is operated by energy supplied to the line wires at the end thereof remote from the iirst approach section While preventing low of 4energy between the portions of the line wires on opposite sides of the intermediate sections, and means effective when said second approach or intermediate section is occupied by a train moving from the second to the first approach section to connect said coding relay across the line wires so that the coding relay is operated by energy supplied to the line Wires at the end thereof remote from the second approach section while preventing flow of energy between the portions of the line wires on opposite sides of the intermediate section. g

6. In cab signal energy supply-means for use in a stretch of railway track over which may move in either direction locomotives equipped with cab signal apparatus responsive to flow of coded alternating current in the track rails, the rails of said track stretch being divided by insulated joints into an intermediate section having Va r'st approach section at one side and a second approach section at the other side, said intermediate and approach sections each being provided with a track circuit including a track relay, said track stretch being equipped with traiiic governing apparatus for conditioning the track stretch for one direction of traflic or the other and including a pair of line wires substantially coextensive with said approach sections and over which coded energy may be transmitted between the track sectionsat the ends of the approach sections remote from said intermediate section, said traffic governing apparatus being effective when the stretch is conditioned to permit traflic to move from the first to the second approach section to cause coded energy to be supplied to said line Wires at the end thereof remote from the first section and being eiective when the stretch is conditioned to permit traflic to move from the second to the first approach section to cause coded energy to be nsupplied to said line wires at the end thereof remote from the second section, in combination, a coding relay located adjacent said intermediate section, means controlled by said coding relay for supplying coded alternating current to the rails of said intermediate section, means controlled by said coding relay for supplying coded alternating current to the rails of the first or the second approach section when andl only when said section is occupied by a train approaching the other approach section and the intermediate section is unoccupied, means controlled by .the track relays of said first approach and intermediate sections for supplying from the line wires to said coding relay energy supplied to the line wires at the end thereof remote from said rst approach section, and means controlled by the track relays of said second approach and intermediate sections for supplying from the line wires to said coding relay energy supplied to the line wires at the end thereof remote from said second section.

7. In cab signal energy supply means for use in a stretch of railway track over which may move in either direction locomotives equipped with cab signal apparatus responsive to flow of coded alternating current in the track rails, the rails of said track stretch being divided by insulated joints into an intermediate section having a first approach section at one side and a second approach section at the other side, said intermediate and approach sections each being provided with a track circuit including a track relay, said track stretch being equipped with traffic governing apparatus for conditioning the track stretch for one direction of traiiic or the other and including a pair of line wires substantially coextensive with said approach sections and over which coded energy may be transmitted between the track sections at the ends of the approach sections remote from said intermediate section, said traffic governing apparatus being effective when the stretch is conditioned to permit traffic to move from the first to the second approach section to cause coded energy to be supplied to said line wires at the end thereof remote from the iirst section andA being effective when the stretch is conditioned to permit traiic to move from the second to the first approach section to cause coded energy to be supplied to said line wires at the end thereof remote from the second section, in cornbination, a coding relay located adjacent said intermediate section, means controlled by said coding relay for supplying coded alternating current to the rails of said intermediate section, means controlled by said coding relay for supplying coded alternating current to the rails of the iirst or the second approach section when and only when said section is occupied by a train approaching the other approach section and the intermediate section is unoccupied, means effective when said rst approach 'or intermediate section is occupied by a train moving from the rst to the second approach section to connect said coding relay across the line wires so that the coding relay is operated by energy supplied to the line wires at the end thereof remote from the first approach section while preventing flow of energy between the portions of the line wires on opposite sides of the intermediate section, and means effective when said second approach or intermediate section is occupied by a train moving from the second to the first approachl section to connect said coding relay across the line wires so that the coding relay is operated by energy supplied to the line wires at the end thereof remote from the second approach section while preventing flow of energy between the portions of the line wires on opposite sides of the intermediate section.

8. In cab signal energy supply means for use in a stretch of railway track over which may move in either direction locomotives equipped with cab signal-apparatus responsive to flow of coded alternating current in the track rails, the rails of said track stretch being'divided by insulated joints into an intermediate section having a first approach section at one side and a second approach section at the other side, said intermediate and approach sections each being provided with a track lcircuit including a track relay, Isaid track stretch being equipped with traic governing apparatus for conditioning the track stretch for one direction of traffic or the v assms 9 'to permit traffic to movei from the 'second vto the first approach section to cause coded energy to be supplied to said line wires at the end thereof remote from the second section, in combination, a coding relay located `adjacent said intermef diate section and controlling the supply of coded alternating current tothe rails of said intermediate sectionf and 'to the rails of said approach sections at the ends thereof adjacent said intermediate section, a rst directional relay which is energized when and only when the intermediate section or one of the approach sections is occupied by a train moving from the first to the second approach section, a second directional relay which is energized when andonly when the intermediate section or one of the approach sections is occupied by a'train moving from the second to the first approach section, means controlled by said rst directional relay for connecting 'said coding relay across the line wires so that it is operated by energy supplied to the line wires at the end thereo-f remote from said first approach section, and means controlled by said second directional relay for connecting said coding relay across the line wires so that it is operated by energy supplied to the line wires at the end thereof remote from said second approach section.

9. In cab signal energy supply means for use in a stretch of railway track over which may move in either direction locomotives equipped with cab signal apparatus responsive to flow of coded alternating current in the track rails, the rails of said track stretch being divided into a plurality of track sections including a first and a second section each of which is provided with a track circuit including a track relay, said track stretch being equipped with traflic governing apparatus for conditioning the track stretch for onedirection of trac or the other and including a pair of line wires substantially coextensive with said rst and second sections and over which coded energy may be transmitted between the track sections at the ends of said f`irst and second sections, said traffic governing apparatus being effective when the stretch is conditionedto permit trafc to move from the first to the second section to cause coded energy to be supplied to the line wires at the end thereof remote from the rst section and being effective when the stretch is Iconditioned to permit traffic to move from the second to the rst section to cause coded energy to be supplied to the line wires at the end thereof remote from the second seotion, in combination, a coding relay controlling the supply of coded alternating currentvto the rails of said track sections, means controlled by the track relays of said sections and effective when said first section is occupied by a train moving from the first to the second section to connect said coding relay across the line wires so that the coding relay is operated by energy supplied to the line wires at the end thereof remote from the rst section, and means con-- trolled by the track relays of said sections and effective when said second section is occupied by a train moving from the second to the rst section to connect said coding relay across the line wires so .that the coding relay is operated by energy supplied to the line wires at vthe end thereof remote from said second section.

10. In cab signal energy supply means for use in a stretch of railway track over which may move in either direction locomotives equipped with cab signal apparatus responsive to flow of ternating current in the track rails, the rails of codedalternating current "the Yt'racl; rails, 'the rails of said track stretch being divided intb, a -piuralii-,y 'of track sectinsincluding a nist-and a second section each of is prdvidedl with l:a track circuit including 'a vtrackfrelay';A 'said track stretch being equipped "with 'traffic governing apparatus fo'rconditining the track stretch for one direction 'or 'traffic er tn'e' 'other 'and including' a pair of line wires substantially coextensive with said rst and second sectionsI and over which coded energy may be transmitted between the track sections at the ends of said rst and second sections, said traiic governing apparatus being effective when the stretch is conditioned to permit traffic to move from the first to the second section to cause coded-energy to be supplied -to i the line wires at the end thereof remote from the first section and being effective when the stretch is conditioned to permit traffic to move from the second to the first section to cause coded energy to be supplied to the line wires at the end thereof remote from the second section, in combination, a coding relay controlling the supply of coded alternating current to the rails of said track sections, means controlled by the track relays of said sections and effective when said first section is occupied by a train moving from the rst to the second section to connect said coding relay across the line wires so that the coding relay is operated by energy supplied to the line wires `at the end thereof remote from the first section while preventing owof energy between the portions of the line wires on opposite sides of the coding relay, and means controlled by the track relays of said sections and effective when said second section is occupied by a train moving from the second to the rst section to connect said coding relay across the line wires so that the coding relay is operated by energy supplied to the line Wires at the end thereof remote from said second section while preventing flow of energy between the portions of the line wires on opposite sides of the coding relay.

11. In cab signal energy supply means for use in a stretch of railway track over which may move in either direction locomotives equipped with cab signal apparatus responsive to flow of coded alsaid track stretch being divided into a plurality of track sections including a rst and a second section each of which is provided with a track circuit including a track relay, said track stretch being equipped with traino governing apparatus for conditioning the track stretch for one direction of traffic or the other and including a pair of line wires substantially coextensive with said rst and second sections and over which coded energy may be transmitted between the track sections at the ends of said rst and second sections, said traffic governing apparatus being effective when the stretch is conditioned to permit traffic to move from the rst to the second section to cause coded energy to be supplied to the line wires at the end thereof remote from the first section and being effective when the stretch is conditioned to permit traffic to move from the second to the first section to cause coded energy to be supplied to the line wires at the end thereof remote from the second section, in combination,A a coding relay, means governed by said coding relay for supplying coded alternating current to the rails of said first section when saidrst section is occupied by a train approaching said second section, means governed by said coding relay for supplying coded alternating current to the rails of said second section when said second section is occupied by a` from ythe rst section and effective when said second section is occupied by a train approaching said first section to connect said coding relay across the line Wires so that the coding relay is operated by energy supplied to the line Wires at the end thereof remote from said second section.

ARTHUR L. JEROME.