US2331262A - Railway traffic controlling apparatus - Google Patents

Description

A'WHLE-KBLE CY" Oct. 5, 1943.

Filed Ailg. 19, 1942 2 Sheets-Sheet l r. M 6 mmf W B 51v... MW. W 5 VY a B r m m r a 27 F 9 5 am M H m m 2 2 H i 5 1 0 0 9 l W w F C] V v r 2 w 1 r 5 m B I III E H 8 T 6 r MW m m I 2% m r 0 c H A w,

H. s. YOUNG I v 2,331,262

RAILWAY TRAFFIC CdNTROLLING APPARATUS Oct. 5, 1943.

Filed Aug. 19, 1942 2 Sheets-Sheet .2

117g ZZASR Z ASE 3 r1" =:B

Fey. 2.

V 15 U T KB Z [YjVBI \2? A [/VVEZVTUR H9121 S.I 0an BY y 3 H15 A7701? Ivar.

7 the United StateSyyNoi 214L074, granted mime ous conditions are avoided. if

retained l armature' *'relays is effecte'd throughlthei inediumtofiitwo position nalcontrol-'re1ays.' v A; e i In practicinmthe; invention:- ytthe above-men'- come readily apparent; fromnthe followingzde-.

ual1y controlled contact, :andiwhich reIayLW'hen released "applies energy to their-track! circuits ofv Patented Oct. e

Myxinvention. relates to ailway. trafli'c cont olling apparatus, 1 andit has particular reference to the organization" of 'suchgiapparatus tintov inter.-

1 locking control apparatusltfor 'c'ontroll'in'gfrom a centrally located acontrolpointqtheswitches and signals" of a track layout'comprising a' plurality of trafiic routes; 1 f V 7 The apparatus ofzmyiinvention'. is arr'imp'rovement upon thatv disclosed inELetters Patent of a 10 onDecember 20,14938, for Railway;traific con trolling apparatus: a s In the patehtl system and others of related character, a-railwaytrack layfout is provided with normally enefgizedtrack cir cuits arranged to cooperate in thecontrolf of-the switches and signals andato refle'ctgtraffic fcondi= tions in the layout, ln' certain applications it is desirable t'o employ normally deenergized track circuits, thereby to avoid undue power e consumption, and it is accordingly-'anbbject of my inventio'n' to provide; interlocking systems incorporating normallydeenergized' track circuitsQ" "Another'jobject of xhj ihventi'on is the pro'vis'ion of apparatus for controlling the application. of

energy to interlockingi apparatus; includingtr'ack circuits, in 'such manner as to permit re'moval of tenergyltherefrom only' when '1:he app'aratus:istin its normal conditioni wherei 'An additional-"object isthefprovlsionlMinter; 3b lockin g. control apparatus employing *tv'vd position to'*- provideif approach retained armature r'elays whi halso 'serve as sigtioned and other; important objects andcharact'eristic afeaturesiof my invention which will: be-

scription, are attained byprovidin'g-a power 'control relay normally energized over a-lstick circuit which includesits' own' ifront contact and a manthe track layout and to auxiliaryiinterlock'ing appar'atus associated therewith. The power control relay is providedcwith a ;pick=up circuit gcontrolled by the vn'i'a'nually operatedcontactfibytrack circuits; and by the associatedinterlockingappara tus and 'whichz'circu-it is arranged to -be 'effective to pickup the Lpowercontrol relay provided 'that thet'trackicirc ts and the associated' 'interlocking 55 i v 1 262 v P RAILWAY TRAFFIC CONTROLLING! I APPARATUS, i,

r S. Young,"Wilkinsbur g Pa., assi at" p i The Union Switch & Signal Company s wiss ope at d\ yae srh h se; e z er; (f e?- 7 Arthur] :G; Kershavv' operated; by solenoij 1 .l the applica n oil-re ays7 in -jm finvention,.togethe -with' severa modifiji grammatic viewillustrating .one form f a pa tus :emb dr ne-mvime i fim alli ee c die am icv ew sh w n m d ca inm I t rsihev ee 1 1 ey d apparatus re in thelconitionjthat obtain when theinterlockingtrack circuim;arevacantand the V tus. To insure the release of SUChflPPI'O JQhIQCkl-Y ing when (in; its normally; deenergi'zed. position-t "lockingris established-tn ghaneme ft wo {3;

position} retained armatur re a or: me;- type: thatjiwh tde ners armatur sin ham it on t-tollwh its ,twofp ti fsne t t en oach lo kin eon bf h a s U e in erno edm e ye ni he-t w h d ip q a suits"totrovide-a a hl ckinatb ta so, the

' signal; control. network t -prQvide a he un t .Azfu;t.the nterposing the}. properoperation I; o the -;relays. k-upon; uch re a s obtai ed contacts-of the switch control circuits: 3'-

- "l-shall describe me amtr'sappa tions' "on .nertio ro helrep a ew j Le -a s mb in my p each oil-the several views,. si mi1a reference h spendingparts.v

T Me lie? e e e fe l d e i e i r ck l ut h wn i the Single li dia I and jcomprising .a portion of a m ain track connected-by attack switch] toa siding-track but I it isto. be understood :that my inventionimaybe applied toother. ztrack layouts involving i-entirely jdifferentcombinationsof Sw tches and signals the (simple layout "disclosed;beingwemployed as'larnex-j i i ample to illustrate" the: principles of; the inven --tion,= The movements of trafiictoverthe several routesyqthrough the trackwlayout are governed. lby imeansi of signalsibefiing' 'the 'reference charg actervii with: distinguishiiig" sufllxes R1 and lining -dica'ting' the direction ortmmc. governed by? such an rmatu e: v

o i e ay m hes' na ndsh th oint element 6, to form a circuit controlling contact.

5-5, when and only when the signal displays its one terminal B of a suitable source of current,

such as a battery not shown but havingitstwo;

terminals designated by the reference charac ters B and C, through back contact 1 of a power minal C, so that relay ITPS is not released as a result of a subsequentmovement of lever 2V.

1 Power control relay ZR is normally energized over a stick circuit that extends from terminal B through contact [5 of a manually operable contact member, herein shown as a knife switch Z,

7 front contact I6 and the winding of relay ZR to .lo most restrictive or stop aspect. Contacts 5-6 of signals 2RA and ZRB control a back'lockingv relay ZRRGP over a circuit that extends from control relay ZR, hereinafter referred to, con- 5 tacts 56 of signals ZRA and 2RB, respectively, a

and the winding of relay zRRGP, to terminal 0. Contact 5-6 of signal ZL controls a back looking relay ILRGP, which relay is energized over a circuitthat extends from-terminal B through back contact 3 of relay ZR, contact 5-4; of signal 2L and the winding of relay ZLRGP to terminalscinril The rails of the tracks comprising-the layout are divided by insulated joints 3,";as indicated in the drawings; into sections AT, IT and .B'I Section IT includes switch i and will be termed hereinafter a detector section,"while section's AT and BT will be "termed eastbound and west bound approach sections, respectively. Each of the sections is provided with a track circuit comprising a track relay, designated by thereference character TR with a distinguishing prefix, and a source, such as a track battery not shownfbut indicated by the reference character 'I'B,'*con'- nectedto the rails at opposite ends "of the sec tion, these connections being indicated conventionally in the drawing. The track circuits for the two approach sections- AT and BT are arranged in the customary manner so as to be 'no'r mally energized and hence each relay ATR and BTR is energized and pickedup whenever its associated section is vacant. The track circuit of section IT is arranged in. accordancewi'th my invention to be normally deenergilned and hence relay ITR is" normally released. Relay "I'I'R is picked up whenever power control relay ZR closes its back contact 5 to apply energy from source TB to the track rails. and whenenergized this circuit then functions on the'closed circuit principle in that the relay isdeenergizedby' a train shunting energyaway from its winding. if

In order to simplify the drawings, *certainfcdntacts of-relays have been representedinthe drawings at points remote from .the relays operating such contacts, but each of suchcontacts bears not only an identifying reference charac ter but alsois, designated by the reference character corresponding to, the relay operating the contact. Thus, for example, contact 9 interposed in the track circuit of section IT bears the reference character ZR to indicate that this contact is operated by relay'ZR; V I V I Track relay ITR is provided with a stick repeater relay i-"I'PS which has a pick-up circuit which extends'from terminal B through'front contact 10 0f relay ITR, the winding of relay I'IPS, and contact H closed in the normal position of a manually operable lever 2V, hereinafter mentioned, to terminal C, After relay ,LTPS picks up, contact of lever 2Vis bridged byfront contact l2 of-relay i'IPS which connects totterterminaLC. In the particular form ,of invention represented in Fig. 1 wherein normally deenergized two position retained armature relays are employed to establish approach locking, relay ZR is provided, With'a pick-up circuit which may be traced from terminal B through contact l5 of ,switch Z, normal contacts I! and 18 of relays ZRASR, 'and, 2LASR, respectively, which relays will be described in detail hereinafter, front contact IQ of relay [TR and the winding of relay "ZR toterminal'C. In a modification of this apfront contact 2| of relay ZLASR, front contact 19 of relay, ITR and the winding of relay ZR to terminal C. In another" modification of the inven tion applicable to lever controlled interlocking systemsinvolving stick control of the signals; re-' layZR may be picked ,up over acircuit repre-- sented in Fig. 3 and which passes from'terminal B; through. contact 1 ii .of switch ,Z,,-contact 23 closed in the-normal position of signal control lever 2V, front contact 18 of relay I'IR and the winding ofprelayZR to terminal 0.. In still'another form-of theinvention, represented in Fig. 4, relay ZR is illustrated: arranged for use in a lever, controlled interlocking system employing non-stick control of the signals. In this form ofthe invention, relayZR is normally energized over astickcircuit which extends from terminal Bthrou'gh contact'fl closed in either the normal or the reverse position of switch control lever .IV, contact 23 closed in the normalposition of signal control lever 2V; front contact cl 6 and the winding movement.

of relay ZR to terminal 0;; and is provided with a pick-up circuit completed at the end of the predetermined time interval of av time element device :lTE that becomes energized'over a circuit extending from terminal B through contact 24 closed in either the normal or reverse position of lever IV,

7 :contact 23 closed in the normal position of lever 2V, front" contactl! of relay I'I'Rqback contact -25 'ofirelay ZR and the winding of time element device ITE to terminal C. When relay ITE closes -its contact 26 at the end of itspredetermined time interval, relay ZRmay1 be picked up over a circuit which includes normal or reverse posielement-device i'I'E and the winding of relay ZR.

to terminal C. The levers IV and 2V, in accordance with the usual custom, will be provided with lever locks, not shown, arranged to prevent a fmovement of lever IV unless trafiic and locking conditions are favorable; and to prevent a movement of lever 2V unless the position of the switch governed by lever IV is favorable for such lever In such an arrangement, the movementof'lever 2V is thus made'dependent upon anjoperati'on of'a device ,(autrackoswitch), con,-

armature type, h t s, h ay a an rmature whichis operable to either of two positions and which is retained at its last operated position when the relay-is deenergized. These relays .are incorporated into the route circuit network where they are controlled by signal lever 2V in such manner that relay ZRASR maybe operated from itsnormal or left-hand position to its reverseor right-handposition only when lever ZV-ismoved to its right-hand position and the other approach looking relay ZLASR isin its normal position,

whereas relay ZLASR maybe operated from its normal or left-hand position to its revers'e position. only when lever 2V is moved to its left-hand position and the other approach, locking relay 2RASR isin its normal position. The approach locking relays 2RASR V and ZLASR, further are controlled by lever W in such manner that relay 2RASR may be operated from its reverse back'to its normal position on y whent lever 2V i mo: .intermediateits normal-and left positions, whilerelay ZLASR maybe operated from its reverse back to itsnormal position only when lever ZVis inor intermediate itsnormaland right positions.

Specifically, relay ,ZRASRcomprises aftwov winding two-position relay having, a normalwinding '60 provided with'an energizingcircuit which eirtends from terminal B through front contact relay ZRARis then released. The normal wind- .ing of relay 2RA SR maybeenergized when switch I. is reversed and/or ection AT is occupied,if a train occupies section IT and releases relay ITR tocomplete a branch circuit path; including back contact of relay ITR, aroundcontact 62 of re lay ,iWP and contact 63 of relay ZRAR. Under other conditions,. the normal winding'lio of relay QZRASR may be energized at the end of a predetermined tim interval establishedthro'ugh the I medium of a time element rela ZRTE and time element stick relay ZRTES. Relay ZRTE is provideo with an energizing circuit which extends from terminal 13 through front contact 6! of relay ZRRGP, polar contact '66 of relay ZRASR closed A inlits reverse or rightehand position, back contact 61 of relay ZRTES and the windingof relay ZR'I'E to terminal C. When relay ZRTE picks up atthe end of its predetermined time interval, its front contact 68 closes and relay ZRTESthen becomes energized over a circuit extending from terminal B through front contact GI of relay 2RRGP, reverse polar contact 66 of relay ZRASR, front contact 68 of relay ZRTE and the winding of relay 2RTES to terminalC. Relay ZR'IES then closes its front contact 67 and completes for itself a stick circuit in which the front point of its contact 61 bridges front contact 68 of relay 2RTE.

The'back pointof contact 51 of relay ER'IES is now open and relay ZR'IEaccordingly becomes deenergized and at the end of'a predetermined time interval closes back checking contact 59 of relay ZRTE to complete a branch circuit path, including that contact and front contact 10 of relay i-RTES, around normalpolar contact 62 of relay aaaare iWPand frontcontact 53 of relay ZRAR, whereupon relay 2RASR becomes energized. V l I Normal winding of relay ZLASR may be energized over a normal circuit extending from terminal B through front contact H of relay ZLRGP, front contact 12 of relay ZLAR, contact 13 closed in or intermediate the normal and right-hand positions of lever 2V, and winding 60' of relay ZLASR tov terminal C. This circuit (has two branch paths around front contact 12 of relay ZLAR, one branch path comprising back contact 14 of relay ITR and th other comprising back or checking contact 15 of time element relay ZLTE and front contact 16 of relay ZL'I'ES. The time elementrelayZLTE and time element stick relay ZLTES are controlled by operating circuits which include reverse'polar contact 18 of relay ZLASR, and front contact H of relay ZLRGP, and which circuit elements are arranged in circuits ubstantially corresponding t th circuit pig iously traced for relays 2RTE and 2RTES.

The reverse winding 59 of relay 2RASR may be energized over a circuit that extends from terminal B through frontcontact ll of relay ZLRGP, normal contact 13 of relay ZLASR, contact I! closed in or intermediate the normal and righthand positions of signalcontrol lever 2V, contact closed in the normal position ofswitch lever IV, normal polar contact SI and front contact 82 of relay IWP, contact 83 closed in the right-hand position of signal control leverZV, and winding 58 of relay ZRASR to terminal C. If switch lever IV is reversed so that its normal contact 80 and normal polar contact 8| of relay IWP are open, an, alternate path is thenestablished in this circuit through reverse polar contact 8| of relay IWP f'andcontact 84 closed inthe reverse position of vlever IV. 'An energizing circuit for reverse winding 5.9of relay 2LASR may be'traced from termi-r nal B through front contact 6| of rela ZRRGP,

normal Contact 56 of relay 2RASR, contact 85 closed in er-intermediate the normal and lefthand position of lever 2V, front contact 82 and normal polar contact 8| of relay iWP ccntact 80 closed in the normal position of switch control lever IV, contact 85 closed in the left-hand position of signal control lever 2V and winding 58of relay ZLASR. to terminal C. This circuit also has .a branchfpath including reverse polar contact 8| "of relay IWP and contact 84 closed in the reverse position or lever IV. v

Signal ERA may be cleared, when switch I is in its normal position; over a circuit extending from 'terminal B through front contact of relay. ZLRGP, normal contact 9| of relay ZLASR, front contact 32 of relay IWP, back contact 93 of relay ILSR, reverse contact 94 of relay 2RASR, contact 95 closed in the right-hand position of signal fontrol lever 2V, front contact 96 of relay ITPS, normal polar contact 91 of relay IWP and the operating elementrof signal ZRA to terminal C. When switch lis reversed, signal ZRB may be cleared over a circuit-corresponding to the circuit of signal ZRA but including reverse polar contact 91 of relay IWP and the operating element of signal 2RB in the place of normalpolar contact 91 of relay IWP and the operating ele- L'ment of signal ZRA, respectively. Signal 2L may be cleared over acircuit which may be traced from terminal B through front contact 98 of relay, ZRRGP, normal contact 94. of relay 2RASR,

back' contact 93 of relay ILS R, front contact 92 of relay IWP, reverse contact 9lof relay ZLASR,

I contact 99 closed in the left-hand position of signal control leverZY, front contact I00 of relay a beconies energized over its previously lTPS and'the ;operat'in elementof signal-"211] to terminal 0; It is to be n'oted thatasl'grials iRA and l ZRB can be cleared f only when 'approach locking relay 2RA SR' is in its reverse pos'ition' to clofse its' reverse rr'ontact 94-" while" 'signal zL' may bec'leared only ifapproach locking" relay {2 LASR is iri'"-its reverse positio ande1oses fits reverse contact 91'; Furt iermor 'itis to' be hoted that the circuits-for clearing all Ofthe sighalsinclud accordingly suchfcir'cui Toenerg iz e the'int I Y the a r f w tch th n r zin power control relayZR.'v RelayIZRia cordingly "releases and as a result; relays I TRYQRRQGP and a 'ZLRGP pick up,'whi1e relay IWP has its operating V circuit completed atback cqntact 34fo f 'rela'y ZR and hence" isplaced'underj the control of switch I andswitch nachine 1| SMQ; When relay I'IRpicks I "switch locking rela flLsR'. and stick repeater 9 f1 f re 'i ITPS become energized, whilei'when back l j loekin'gjrelays ZRRGPandZLRGI-Fbecom pic gd "fupljth'e normal 'WindingsTQIQre Q Y :ator a e' lever jzvtqlits rightorits left position,

"respectively If the "lever is inove cl "to its right position, the rev ersezwin ng of relay @RASR then it-fincl'uding r ont contact 1| r m y ZLRGP, ,jn rmaI contact 18 oferela LA s R y-right-yhand tioi'it'q i 8310i lever i vandf re "r se winding lfi}! of relay ZRASR'. The reverse energiz lationiof relafy JBfASR causes its normal contact 59 toopen and .deenergi ze switchflockinfrelay' I LSRJ; normal backcontac't- 93 o f-fswitch' loclrinlgfrelay IPSRJ ans ,sremio traced cirrelay lRAsR is restoredhtoi-its'normal condition," 5 1 thusenabling locking relay; lLSR1to be ,pi'ckedji 'p- 2 tot unlock switch L45; The switch may; then be operated to establish a different routecthrough the layout, n being-noted that operation crime switch isa delayed-for the predetermined time Q.

interval of the time elementidevice tovprev'enta 1 switch movement i in front of'an approaching H trainjand to enable the Etrain to be' broughtatoa 2h ne v v in r locking may be released' faftersignalflzwiis sfe'tQ I 'tojfstop,only'by thetrain-acceptingsignal 213B v and entering section; lf 'or at the end ofithe pre 1 I viously "traced time interval of devi contact ,ll interposed'in matt ng-up;6 mm; of a 7 t jpowertcont'rol relay ZRalso opens;,whil ereyerse contact 94Hofrelay 2RASRploses1tocompletethe, Qpperating circuit previously tracedior signal IRA, v

' 'f which. circuit includes front contact 99, of relay ZLRGP, back contact 93 qfrclay} I 'LSR,--and lever Contact 95 closed the right hand position of 1 "l v r" V w ere riisi na Acle rsandasa r LQQ Iar hQ-OQ Q v ,hanjd, IeverZVfhad beenoperatedfrorn normal i't'oits left-hand position; then relay zLg sla jwould have. been reversed andfsi'gnal 12L would ,have

cieared, 'asislobvious frorn an inspection of the 60 drawings. a 1 w Inflthe event that either main line signal 23A ToriL is cleared, the'signal may, be'put'to stop by restoring lever 2V to its'nlormalposition, When signal '2RAis put to stop; the normal winding 60 "becomes energized and that relay is operated to itslnormeil"positionl provided that approach .sec-

:"tion AT is vacant sothat frontcontact 6390f relay is closed. 1 If;,however;;section A'Ifis occw pied,l"the n relay: 2BAR is --released and relay 7 ZRASR is'retained in its rev erse position :until time element; relays ZR I'Eand ZRTES operateto ,Provide a time release circuit. When this time .q-relcase cirQilit. r viously, raced, is esta of the associated approach lockingrelay ZRASR,

up over its piekj -upf circuit. This] circuit li cludesfront contact 19 0f relay {TR and li ence requires, the associated track circuitfto be ya? I 1 icked up rn addition} this circuit includes ennacontacts- H and I8 of relays I ZRASR and, 2LASRj-which 70,-quireaminimum offener'g y '-::Although-iI.-have herein shown and dose only a few forrns of railway traffic; controlling" apparatus embodying my invention-,-'it is"understood "that various changes:and-modifications I 7 stop short of, the switchx. Theother approach locking relay 2LAS'R isksimilarly controlled iby' relays ZLAR, ZLTE and 2LT;ES, -jas is obvious' from the drawing and the previous description of; =the"circuits.'- a o o n Atrack circuit release of the approach locking is provided when lever ZY'is restored to its-normal {6;

position after' a train passes the cleared signal and enters detector section IT. For examplegif 1 signal 2RA is cleared, the sighalisplaced atstop V i when thetrain entersfs'ection f-l l"because relay releases to in turn releasejrelay"ITPS and open front contact" 96 interposed iri the, operating II circuit of signal ZRA. Back 1ocking;re1ay 2RRGP" accordingly closes its frontcontact El and ifble v'er l 2V is restored to its normal position; then normal;

winding' fifl of'relay "ZRASRIV becomes nergized,

and relay ZRASR is restored to its norn'ial condi a tion -to release-the approach lockinz switclr locking relay ILSR is atPthis-tirnehield d'eenefgize'd, however; at front c0ntact;52 ofrelay ITR.

and hence operation of the switch will pref n ventedf Y locking eifected through a front'contact pr the approach relay is p1'ovided-"forsig-na1 23.135 Si nal Zhfhow'e'v'er; is provided with the usual -When the interlocking" apparatus is ire" ed to its/normal conditiomrelay ZR may be pic" cant in "order for relay ,ZR to be relaysin turn require lever 2V to be 'i n its'norniail --'position so that all signals are at stop; It fol- Y "lows,-therefore; hatl'whe'n switch, Z 'isclosed,

may be made.lthereinz within the scopel-iof the' inal release as 'wellas'trackfcircuit "and t rne mrelease.

said lever and effective in its said normal position for positioning each of said relays'in the .second of two positions, and means for positioning'one of said relays'in its said first;;position over a circuit including a second position contact of the other of saidrelays and .a contact of said control lever closed in one of the extreme positions thereof 1 and :forpositioning' said .other re- ;lay in its said first position over a circuit including a second position contact of said one relay and a contact of said control lever closedin the other extreme position thereof.

2 In combination, a railway track layout including a track switch, two opposing signals one .at each end or a trafiic route over said switch, a

.two position retained armature relay for each of said; signals, means-controlled by each of said two position relays when in a first of its positions for clearing its associated signal, a control lever having a normal and two extreme positions-nib cuit means governed by said lever and effective in its normal position for positioning each of said two position relays in the second of its two positions, means for positioning one ofsaid two position relays in its said first position over a cirlcuit including a contact closed in the second position of the other of said two position relays and a contact of said lever closed in one of the extreme positions of said control lever and for positioning the said other ,two position relay in its said first position over a circuit including a contact closed in the second position of said one two position relay and a. contact of said lever closed in the other extreme position of said con-.

trol lever, a switch locking relay, an energizing circuit for said switch locking relay including a contact of each of said two position relays closed ,in said second position thereof, and switch control means including a front contact of said switchlocking relay for operating saidswitch.

3; In combination, a railway track layout including a track switch, a pair of two position retained armature relays one for each direction of traffic over saidswitch, means governed by a manually controlled contactor in a normal position for positioning each of saidtwoposition relays in a normal position, means governed by said -manually controlled contactor-in one operated.

position for positioning one of saidtwo position relays in an operated position over a circuit including a contact of the other of said two position :relays closed in said normal position thereof, means governed bysaid manually controlled .con-

tactor in another operated position for position ing the said other two positionrelay in its operated position over a circuit including a contact of saidone two position relay closed insaidnormal position thereof, a switch locking relay; an

energizing circuit for said switch locking relay including a normal position contactof each of said two position relays, and switch operating means governedbya front contact of said switch .locking relay for operating said switch.

4. lnpafrailway interlocking system, a track sectionincluding a track switch, 'ajpower control relay normally energized over a stick circuit including. its cm front contact and a manually controlled contact, .a track circuit for. said section 'includingatrackrelay and aback contact of. said power control relay,,an approach locking relay having a normal and an operated position, manually controlled means ,for operating said p ro c locking r a rtc it .QP Qted posi io an approach relay responsive to traffic :approach ing said switch, a time elementdevicehaving a time contact closed at the'endof a predetermined timeinterval, means governed by said approach relay for operating said approach locking relay to its normal position when no trafilc approaches.

said switch, other means governed by said time contact of said time element device for operatingsaid approach locking relay to its normal position ,whentrafiic is approaching said switch, a pick-up circuit for said power'control relay including said manually controlled contact and a normal position contactotsaid approach locking relay and, a front contact of said track relay, and

means'governed by" a front contact of said track relay and a normal position contact of said approach locking relay for operating said switch.

5. In combination, a stretchYof railway track having a track section including a track switch, a retained armature two position'lrela'y having a normal and an operated position, rneansgoverned by a manually controlledbontact for operating said 'twoposition relay to its operated position,

2; signal governingtraffic in one direction over said switch, means governedby an operated positionco'ntact of said two position relay forclearing saidsignal, a" 'powercontrol relay normally energized over astickf circuit including its own front contact and another manually controlled contact," a track circuit 1301f said section including a track relay and abackcontact of said power control relay,v a pick-up circuit. for said power control-relay including a normal position contact of said two position relay and a front contact of said track relay and said other manually controlled contactyan approach relay governed by trafficon said stretch approaching said switch, a circuit for operating said two position relay to its normal'position including a third manually operated contact and a contact closed when said signal is atstop and a contact of said approach relay closed when said stretch is vacant, an alternate path around said contact of said approach relay comprising a back contact ofsaid track relay, atime element device energized over a cir- "cuit including said contact closed when said sig- -na-lyis atstop and an operated position contact of said two'position relay, another alternatepath around said contact of said approach relay comprising a contact closed at the end of a predetermined time interval after said time element relay becomes energized, and switch control means governed by said two'position relay and rendered effective when said two position relay is. in its said normal position.

6. In combination, a stretch of railway track having a track section including a track switch,

a retained armature two positionrelay having a normal and an operated position, means governed by a manually controlled contact for operating said two-position relay to its operated position, a'signa-l governing trafii-c in one direction over said stretch, means'governed by an operated position contact of said two position relay for clearing said signal, a power control relay normally energized over a stick circuit including its own from contact and another manually controlled contact, a track circuit for said section including a track relay and a back contact of said power control relay, a pick-up circuit for said power control relay including a normal position contact of said two position relay and a front contact of said track relay and said other manually controlled contact, an approach relay governed by traflic on said stretch approaching said switch, a circuit for operating said two position relay to its normal positions including a third manually operated contact and a contact closed when said signal is at stop and a contact of said approach relay closed when said stretch is vacant, a time element device energized over a circuit including said contact closed when said signal is at stop and an operated position contact of said two position relay, another alternate path around said contact of said approach relay comprising a contact closed at the end of a predetermined time interval after said time'element relay becomes energized, and switch control means governed by saidrtwo position relay and rendered effective when said two position relay is in its said normal position.

7. In combination, a track section including a track switch, two opposing signals governing movements over said switch, a two position re- .tained armature relay for each of said signals,

means controlled by each of said two position relays when in a selected one of its positions for clearing its associated signal, a control lever having a-normal and two extreme positions, circuit means governed by saidlever and efiective'in'its normal position for positioning each of said two other position of said One'two position relay and a contact closed in the other extreme'position' of said lever, a powercontrol relay normally energized over astickcircuit'including its own frontcontact and a manually controlled contact; a

track circuit for said track section including a track relay and a back contact of said power control relay, "a pick-up circuit for said power icontrol relay including said manually controlled con tact and a front contact.ofsaidtracl; relay'and contacts closed in "said other position of each of said two position relays, a switch locking relay, an energizing circuit for said switch locking relay including a front contact of said track relay -'and a contact of each of said twoposition relays closed in the said other position of that relay,

and means including a front contact of said,

switch'locking relay for operating said switch,

HENRY S."YOUNG.

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