US2365344A - Railway switch lock control system - Google Patents

Description

Dec. 19, 1944. T, L JUDGE RAILWAY` SWITCH LOCK CONTROL SYSTEM Filed Feb. 5, 1943 2 Sheets-Sheet 1 O JAL@ L E m 25m @EEE m l@ Win21 20 E. 5

Dec. 19, 1944. T, JUDGE RAILWAY swITCH LOCK CONTROL SYSTEM 2 sheets-sheet 2 y Filed Feb. 5, 1943 .udpcov 1 OG b o r Patented Dec; '19, 1944 RmWAY'sWrroH LocK 'CONTROL SYSTEMv Thomas Joseph Judge, to General Railway Rochester, N. Y., assigner 10 Claims.V

'This' invention relates to systems for safeguarding traic on railroads, and more particularly to devices and circuit organizations for protecting hand-operated track switches locatedl along the-main track of a railroad.

Many railroads haveA track switches connecting with passing sidirIgS, storage and industrial tracks, andthe like, which are manually operated by a Atrainman from the normal or main track position toa reverse position as occasion may require for train movement'into and `from the main track; It will be readilyappreciated that such hand operation of the track switch should not be performedV for turn-out train moverV ments if vthere is some other train on the main` track which intends to pass over the switch in a main track position at/speed, since a derailmen-t or collision is likely-to occur shoulda switch be thrown `in frontof a movingA train. in order to provide for such circumstances, railroads usually have operating rules which require a trainman to receive special` authoritysuch as a written train order, permission obtainedfrom a dispatcher over a telephone, or the like, before operating a switch to bring a train onto the main track; but since there is always opportunity for error'in the execution of the orders received, it is'v desirable to provide what iscommonly' known as a switch lock with suitable automaticA control which prevents hand operation of the switch except under safe conditions.

Inone organization, a switch lock is provided' sothat a hand-operated' track' switch cannot be manually moved toA a turn-out position unless' the switch lock is released and this release does' not take effect until after a predeterminedtime following the initial putti-ngto stop ofv signals governing traffic over the main track by a preliminary` manual act at the switch. Such an organ.- ization is commonlykncwn as time locking, which permits an ori-'coming train to either be stopped by the signal on the main track having been put to stop,

orV to allow the train to come ywithin sight or trainman will notthrow the switch with that' the a trainwithinsighting distance orpassing over such switch. 'This type of locking provides the' essential protection for trains entering `the main track, but it isf-obvious thatv a' train leaving' the main track would' be unnecessarily delayed if the switch could not be operated luitil after' a predetermined time. To obviate this unnecessary delay of atrainleaving the main track, a short release track section is provided adjacent the switch to permit the release of thejlock while Signaly Company, Rochl i .'Applcati'on February 5, 1943, Serial No. 474,775

a train' is on this tracksection. Such an arrangement is4 disclosedE for example in theV prior pater-l? to S`.` Nt Wight?, Patent' N0. 1,476,866- dated:

December ll', 1928.'

larly in the provision of a' novel organization in connection with the provision of' a release tracksection so as to make it unnecessary to provide control; contacts in they wayside signal circuits at the'- track switch but still7 giving the usual pro-1 tectionof holding the signal at stop as soon1 as the initial manual lying track' switch. i

A further feature-'cf' they invention is that a release track section is included in the. system of" the' present invention in a manner to obvi'ate the necessity of providing a track battery individual toit. j

A further feature of the invention is to 20' ganize the rele'as'etrack section together with the releasing means for the'switch lock that the organization may bei'employed with signalling of either the line circuit type or the coded track i circuit type; f

Various other characteristic features, attriy botes and advantages of the present invention will be in part apparent and in part pointedout as the description progresses.

I-'n describing the invention indetain reference' So'wll be made to the accompanying drawings, in

which similar Ietterrer'erence characters are used to designate' similar parts' throughoutT the var ious figures, in which like reference characters W, have'been made generally distinctive by the use 3,3" of7 distinctive preceding numerals, and in which:

Fig; 1f`ill`ustrates one embodiment of the present invention providing aswitch lock organization associated `with a line circuit type of signalling system; andA passI over such switch, it being assumed Fig. 2; illustratesl another embodiment o f the presentinvention providing a vswitch lock organization associated withvacoded track circuit type of signalling system.`

The accompanying drawings illustrate in a' f5L` conventional and diagrammatic manner two specic embodiments of' the present invention, the parts and2 circuits being shownl ina manner to facilitate an understanding of thefunctions and fop-erationl ofthe invention, rather than to illus- 50"'trategthe detail structure. and' arrangement of parts. preferably employed in practice. Thus, symbols are employed in. t'he conventional manner' for the various devices and sources of electric current instead' oflsl'iowing all of the wiring 55 connections to the terminals' of such sources.

The present llfl'llllOlll relates mOl particu-V acti is performed at the outso or- The symbols (-l-) and are therefore employed to indicate the connection to the positive and negative terminals respectively of suitable batteries or other sources of direct current, and the circuits with which these symbols are used always have current iiowing in the same direction. The symbols (B+) and (B) are used to indicate connections to the opposite terminals of a suitable battery or other direct current source which has a central or intermediate tap designated (C), and the circuits with which these symbols are used may have current flowing in one direction or the other dependent upon the particular (B+) or (B) terminal used in combination with the intermediate-,tap (C). If alternating current is to be used instead of direct current, the polarity symbols employed are to be considered as instantaneous relative ,polarities The invention may be used in connection with any one of the various applications of handoperated switches on both single and double track railroads having any suitable form of block signalling with or without supervisory manual control of the signals and the switch lock by a system of centralized traffic control. In one speciiic embodiment of theinvention, it has been assumed for the sake Aof simplicity that the switch lock organization is applied to a typical outlying switch for the main track of a double track railroad equipped with a conventional automatic block signalling system using polarized line circuits; while in the other specic embodiment of the invention, it has been assumed that the switch lock is employed with a typical outlying track switch for the main track of a double track railroad equipped with conventional coded track circuits.

Referring to Fig. 1 of the drawings, a stretch of track is shown as divided into track sections AT, IT, 2T and 3T. The track section 2T is in effect divided into three portions including a release track rail portion 2TB as well as a forward portion 2TA and a rearward portion ZTC. The release track rail portion 2TB is relatively short, for example, in the order of two or three-rail lengths with suitable insulated joints 1, I3 and 9 separating it from the otherportions ZTA and 2TC of the track section 2T. It will be noted that this track section between the signals 2 and 3 is referred to as a whole by the reference character 2T, while its different portions are specifically referred to bythe particular letter reference character A, B or C following the general term of 2T. This is for convenience in discussing the various characteristics of the release rail portion 2TB with respect to the rest of the track section 2T.

The movement .ofl trains on the stretch of track shown is normally in an east-bound direction indicated by the arrow and legend. This east-bound traiiic is governed by signals I, 2 and 3, which may be of any suitable type, but have been shown as color light signals and are arranged to be `controlled in accordance with established practice by polar neutral home relays H having suitable polarized line circuits. The relay IHfor example, which governs the indications of the signal I in an obvious manner, is controlled over a polarized line circuit, readily traced on the drawings as including a front contactr 5 of track relay YITR., and a contact I of relay 2H which causes (B+) to be applied if the relay 2H is picked up but causes (B-) to be applied if the relay 2H is dropped away.

Thus, in the arrangement shown, if the track.

negative potential is applied to the home relay" lI-Fso that the signal I is caused to indicate caution. Of course, under normal conditions with a train either in the track section 3T or further advanced, the relay 2H is picked up and posi- Vtive potential (B+) is applied to the relay IH so .that the signal I normally indicates clear.

The stretch of track shown in Fig. 1 also includes a hand-operated track switch 2W which may be moved from one position to the other by any suitable hand-operated mechanism. Associated therewith is a suitable switch lock which has been diagrammatcally illustrated for the purpose of disclosing the principles of the present invention, but this lock may be of any suitable type, such as disclosed for example in the Patent No. 1,710,668 granted to J. E. Stephenson, April 23, 1929. In this type of switch lock, a lock rod I0 is connected to the switch points and is held in a normal position by a lock plunger l I locking the switch points in such normal position. The switch points cannot be moved to the reverse position in a direction indicated by the arrow associated with the lock rod ID until the lock plunger II has been raised by a lock handle 2LH. This lock handle 2LH can be moved a limited amount opening certain contacts and cosing othersas will be later described, but is held in a locking position by the lock dog I2 which prevents the release of the lock rod I0 until the electric lock coil 2L is energized to move the locking dog I2 to non-engaging position. When the lock dog I2 is lifted by the energization of the locking coil 2L, then the lock handle 2LH may be moved in a counter-clockwise direction to raise the locking plunger II to disengage the hole inthe lock rod IU and permit handopera-tion of the track switch to its reverse position. It will be noted that the lock handle 2LH cannot be returned to its normal position until the track switch 2W has been returned to its normal position for main line movement because with the lock rod I0 in a reverse position, there is no hole tiu'ough which the lock plunger I i may pass.

Also, associated with the switch 2W is a suitable switch box or circuit controller having contacts which are closed only when the switch is in a proper normal or reverse position and this switch box is shown as having contacts I4 closed in the normal position only. For simplicity in the disclosure, these contacts are indicated as operated by the lock rod I0, but usually a separate rod is employed to connect such contacts with the switch points.

Other elements of the switch lock include door contacts I5 which assume one position when the door (not shown) for the switch lock casing is closed, but assume another position when thev door of the casing is open, it being understood that this door must be open in order to gain access to the lock handle 2LH. The structure of the switch lock casing may also be such as to prevent the closure of the door to operate contacts I5 to their normally closed positions un.

less the lock handle 2LH is in its normal position.

Also associated with the electric switch lock is atime element device 2DT which may be of any suitable type. This time element device is slowl accesos isfprovidcd on this timing .device which is x not". clcsedunti-l. afterl aA .predetermined inter-.wal of, time has been measured, hutis immediately opened as soon as thc-,timing device zTD is doen-.- erg-ized. This timingl deyice. Z'ITD may be of; any'. suitable type. such asy shown for example inthe PatentNo. 2-,J.-9,335 grantedl to Q.. Stililielm April, 36l194-.0-, or it. may bei a. thermal relay' and ani associated. repeating relay, or any other suitable organization for; measuring a, relatively long time interval such as. for example four tofsix minutes.. f Under normal conditions, the, track batteryl; supplies energy throughv aA circuit including.- the. upper rail of track section 2TC, over the jumper-- cable 21|.l to the lower rail of track section TFA, through. the track relay 2'1`R- tothe upper rail of. track section` 2-TA through suitable track con-` nectionsiincluding back Contact.l 22. ot relayv 2WLT front contact. 230i relay ZWLP, to: the release. rail. 21315 and over suitable track con. nections including front. contact 245 ot relay ZWLP, to the lower rai-l of track: section 2170,. to the negative side of the track battery 2.0. Thu-st the track relay lTR- is energized closing front; Contact l3ft so that. relay 2H. is energized and sie-- rial 2` for the main. track indicates clear. l

track, relay 2ER. yto he: immediately .deenereized Opening its:l front contact 31H5 and thereby causingl the signal; 2 to. he: placedv at stop andthe signalA I'. to indicate caution. As. soon as the back; contact: 3 l! of relayV ZWLP iszclosed, it is apparent that a circuit isclosed from. (ft-)3, and including door contact l5 in a left-hand position back contact 3.|' oai relay EWLP, windingsof tim-ing device ZTD, to, t-),'.. This energization ot the.- tim-ing dev-icc TD immediately open-s the' checking-v back con-v y tact l'lr and begins. tomeasure ott a. predetermined. time after which. frontJ contact i8 will be closed.. f f

The trai-aman.- will then move the lock hand-le 2LH apart. of. its possible. movement; away tro-m its normal. position which opens: contact 2.6, in the normal position thus further insu-ring` that the. relay ZWLP is delenergized,v and closes, con-tact 3.2. in the position commonly known as. thea B posi tion. y contacty 32 isalso. completed with the lever. 2LH in. any other position up to. the reverse position. Such afcontact is commonly termed. aziRB contact. Thus.. after a predetermined time hasheenmeasured. by the slow-actingY tim-ing de vice; ZTD, front contact. i8 is closed andiv ay circuit` is` closed including contact- 31 in; the B1 position The switch 2W is oi course lassumed to be in;

a normal position and locked with the dooro the switch lock casingi closed so that energy/is. supplied from. 6.4.-), through a circuit including door contact. l5 in. ay right-hand position, windi-v ings of a. relay ZWLP, hack checking. contact lil of' timing, device ZID, hack contact 2:5 of lock magnet 2L, lock contact 26, in. a. normal position-y N-.,. switch. box. contact I4 in. anormal. position, to f This energization-of the switch. lock repeating relay ZWLPpmaintain-s its front contacts 23 and 2 4.' closed so as to complete'. theftrack circuit Z'It.y

as. above pointed out y In connection with. the operation of hand-opy crateri track switches, particularly territory where there is supervisory manualcontrol-ovei-r.- y

the signals. and poweroperated. track switches by a centralized trafficy control system, itmay he desirahle to provide manual supervisory control over the switch. lock in order to give the dis.

patcheror operator control over the. release of the track switch. Thisis provided particularly to. prevent the switch, from.. being hand-operated to allow a train to come. onto the main track. when such` movement is contrary to the wishes of the.

dispatcher and might otherwise occur due to the careless action of a train crew or perhaps dueto amisunderstanding. of the d'i'spatcher"s. instruc tions received. over. a telephone. Although, such.. `manual supervision. of.' the outlying. switch lock may be provided ifA desired; this has not. been, shcovnv in connection with. the. present. disclosure for the, sake of simplicity but. may be readily ap- Diled to the organizato disclosed if this is. dcsired.

Assuming that a trainm overv the` telephone thathe switch an. has y'receiyed orders 2W to a reverse position` and allow his.y

trainl to proceed over the. main. track, it is. as`

opens the door. of the` sumed. that the trainman. switch lock casing` and thus permits. the con.- tact f5 to be operated. to a.l left-hand position., This immediately deenergizes the relay ZWLI?V may operate-the track.

to energize the lock magnet 2L., The: energize..- tion. of this lock. magnet; 2L- raises the locking dog. i2; tolrelease the. lock. handle 2LH, and at. the same; time opens back contact 25I also. included. in. thecircuit for the relay ZWLP.. With the. dog

I2v in a, raised', position,X the lock handle 2LH may he moved.. to. itsunlocking; position so. that, the lock plunger t( will release the. switch 2W and permit. it to' he manually operated to its reverse. positi'om It wi-I-Ithus be. seen that. a train standing on theA turn y enterthe main track, and when the ldoor of the switch lock boi` is ope-ned. the. signals. are.- placed. at. stop. by i'rmierrupti'ne the track circuit con.- trolling, the, passage of traiic over the track.. switch ZW, but. `the 4switclzi is. not released for movement. to. its. reverse signals. have been. held mined periodoftime. e

When the train has passed over the. switch 2W' onto the main. trafila. the tranman, then. operates the switch. ZW'to.. its. normal position replacing the lock. handle. 2LH which deenergizes. the lock magnet 2L and alsc'iv closes contact 26 in anormal positiom Thus, as. soon as he closes the doorof the switchlock casing, contact. 155 is moved to a relay ZWLP as soon as. the slow-acting. timing. de.-

l vice. assumes, its restored.

normal position` closing checking contact i1'.

Considering. the above description with respect to it. will beseen that. the initial opening.

of the. door of the. switch lock`d`eenergizes. the relay KZWLE, which opens the circuit for, the track relay 2.TB at front; contacts .Z3 and.r 24.'so that. the. track relay is; deenergized. opening, front contact. tofdeenergizethe: home relay 2H. ThisL causes the. ysignal 2; tot displayV a, stop. indicationv and' to sor controtsig-nal i inthe rear thereoi so out-,track will. proceed. in. an east-bound direction` corresponding tothe normal-direction of trailcj.v

.-out track may receive.- instructions to positionuntil after such. aty stop for a.. predeter- 5 after the switch 2W has been restored to its normal position. However, a train might proceed in the west-bound direction against the normal direction of trafc either under special orders from the dispatcher or suitable reversed signalling might be employed although the present disclosure does not show suchsignalling for both directions of tra-rho.

With the normal direction of traffic for eastbound train movements, it will often happen that a train in approach to signal 2 will desire to enter the turn-out track. The train in passing the signal 2 of course deenergizes the track relay 2TR by shunting the track rails of the track section portion 2TA, and this deenergized condition of the track relay 2TR` is maintained throughout the time that the east-bound train is in any portion of the track section 2T and until such train either passes beyond the signal 3 or over the switch 2W onto the turn-out track.

Assuming that the train desires to` enter the turn-out track, it proceeds onto the release rails 2TB which still maintains the shunt on the track relay 2TR in an obvious manner. The train stops and sends a trainman to the switch 2W who opens the door to the switch lock casing which moves contact I 5 from its right-hand position to its lefthand po-sition. This deenergizes the relay 2WLP and sets the slow-acting timing device 2TD into operation. However, the trainrnan immediatelsr begins to operate the handle 2LH because with the train on this release track rails 2TB it is unnecessary for the predetermined time of the slowacting timing device 2TD to elapse before the switch lock is released. This is because the presence of the train completes a circuit from the lower rail of track section portion 2TC through back contact 24 of relay 2WLP, relay 2WLT, back contact 23 of relay 2WLP, release track Section 2TB through the axles of the train to the upper rail o the track section 2TC. This circuit causes the energization of the relay 2WLT closing front contact 35. Thus, as soon as the trainman movesl the handle 2LH to the B position, a circuit is completed through contact 32 for energizing the locking magnet 2L and permitting the continued operation of the handle 2LH to release the switch 2W for manual operation. The energization of the lock magnet 2L opens back contact 25, while operation of lever 2LH from a normal position opens normal contact 26, and the operation of the switch 2W to a reverse position opens switch box contact I4, all in a manner previously described, so that the relay ZWLP is maintained deenergized until the train has passed over theA turnout track and the trainman has restored the switch 2W- and lock mechanism to its normal condition in the rear of such train.

In this way it is seen that an east-bound train may pass onto the turn-out track without waiting for the predetermined time to elapse as is eiiected through therelease track rails 2TB. It is noted that the energization of the relay 2WLT is accomplished by what may be termed a series relay connection to the track which is supplied with energy from the track battery 28.

The present organization is protected against thev measured by the slow-acting timing device 2TD, which .dentally break down, then a circuit is closed from'v that it drops away under such circumstances and causes the signal 2 to indicate stop. Thus, any erroneous break-down condition of the insulated joints 8 and 9 is self-betraying through the control of the signal 2. The break-down of the insulating joint 1 during the absence of traiic produces no unsafe conditions with respect to the signalling system, but is not self-betraying until the useof the release track section is desired. For example, it is seen that the break-down of the insulating joint 1 causes a shunt across the track relay 2WLT so that the switch lock will not be released until after a predetermined time even though a train is standing on the release'track' rails 2TB.

In this way, release track section control of a switch lock is provided without the use of an additional track battery and in a manner which properly maintains the signals at stop while the switch is unlocked and protects against accidental breaking down of the insulated joints associated with the release track section.

Operation of Fig. 2.-The principles of the invention have been disclosed in Fig. 2 in connection with the use of coded track circuits for the signalling system. The same type of track layout is shown in Fig. 2 as is shown in Fig. 1, but the track sections have been designated as track sections 4T, 5T, 6T, and 1T, the track section 6T being divided up into a forward portion BTA, a release track ETB, and a rear portion GTC. Signals 5, 6 and 'l are shown for governing traine over their respective track sections.l These si"- nals are shown as controlled by the usual coded track circuit apparatus.

More specifically, a code following track relay STRis associated with the signal 6, and operates at the particular code rate received over the track section. The track relay GTR acts through suitable decoding apparatus to cause the relay 6H to be maintained energized whenever any code is being received, but causes the energization of the relay 6D only when a particular code rate is being received. For example, the code rates '75 and 180 impulses per minute may be employed, the '75` code rate being for a caution control and the 180 code rate being for the clear code period. The

reception of the 75 code by the track relay GTR will cause only relay EH to be picked up, while the reception of the 180 code by the track relay GTR will cause both relays BH and 6D to be picked up. Similar operation occurs in connection with the decoding apparatus at all of the signal locations.

Associated with each signal is a code transmitting relay CP which is controlled ,in accordance with the condition of energiaztion of the associated home relay so as to impress a clear or caution code in the rear of that signal depending upon traiic conditions in advance. For example, the code transmitting 4relay GCP is controlled in accordance with a 180 code oscillator IBUCT through front contact 5B of relay 1H under normal conditions. But if a train is in the block in advance of the signal 1, then the relay TH is deenergized closing back contact so that the code transmitter SCP is controlled in accordance withy the operation of a code oscillator T5CT. These code transmitters or oscillators CP may be-of any suitable type, such as motor driven contactorsor of the spring balance type such as code isl of the caution `:giaes the red lamp ol signal 2li.'

' fS'WLT includes from ithe shown kin I-tl'ie vprior application -of '0. S. r'Fiel-d, VSor. vNo; "3695862, -led l'December T2, 11940, it being sufficient for the purpose of the present invention to know that 'thesefcontact's are operated at l'some predetermined r'code Arate-such as indicated 6 zessen 'GWLT a left-hand position.' "Thus, the codev vfollowing track relay STRreceives 'code 'as )transemitted *from the exit fen-d df 'associated track section i6T. Under 'normal conditions, this code is -of course a clear code of I'the v180 `code rate so that 'both 'the `relays tcompleting a circuit for I4'the green*lamp o'f signal v6 through iront contacts e6 of relay 6H and front contact 5l of relay 613. y(Dnlthe other hand, ,if the "l5 'code rate, fthe 'relay' '6D would be "deenergized lenergize 4the yellow llamp of signal '6.' If bothrelays and l"6I-l -arev de ener'gized, then vit :is obVious that the hack contact"56 of 4relay Aener- In a 'similar 'manclosing 'back contact 1si to! '25 ner, each signal is controlled by 'coded track cir- 30 i uits in 'accordance with traffic conditions in advanne, it being understood of course that a release track, such as STB, is included only in those sections wherea switch look is employed.

'The switch flock apparatus for the same as show-n .in Fi'gjfl-and is controlled `in Xexactly the same manner except `that the vrelease ltrack section yrelay WET *is Aof the polar-mag- :.netic ,stick type. In .other Words, this relay is Fig. 2 "is exactly."X3

provided with 'a 'polarized structure so *as to op! 40 crate .its Ycontacts to Ione position or the other depending upon the polarity with which it is 'energized, but zits contacts remainin their last 'ac-y .tuated positions A.until energized with the opposite polarity. lthe :operation (of lthe #switch lock as given in lconnection with Fig.- l :will apply to the 4operation with respect to Fig. except as to the 'operation .surrounding the use of the `release track vsections, @STB'involvingzthecontrol-'ofthis relay G'WET.

More `speci-'iically, 'it lis fbel-ieved junnecessary ,to point out -in fdetal how cthe track switch "GW may be released for a train on theiturn'out track vwhich -to :enterthe main track lloe'caiisethe slowactng timing device STD :determined time Aunder such `fcircurns`tances to lclose Vto iront :contact i60 and energize theI lock magnet :6L :to release the lock handle B'LHin the samer-manner `poi-hited out in detail in lconnection 'iwiith Fig. "1. However, :trai-n standing on ftherel'ease section STB desiring itolenter kthe `turn-out track icauses .operati'onof fthe relay GWLTto a righthand position foy mensen lof the current 4iiow .through the lower winding of when the ftrainman opens 'the door -oftheswitch lock casing and :contact 58 closes in a left-'hand position. )More specifically, 'Ithiscircuift `Eor relay -po'sitifve side lof battery' 52, llower 'mail lof STC, 16WLR11l-ower winding ofirolay '-back conftact '.54 of relay 6WD?, release `track section 6TB, aides :of fthe train, mppe'r frail `of the ftrack section :'GI'IIC, :to megatiwessidero battery 82. Although on- .operates after a pre- Thus, fthe fdescr'iptfion'withregardv to' '215 Yco l.hack Icor-rtaot l53 of relayr v7'0 'lfypulsesnf codenrrentfpassthrough this circuit, 7'5

`The energy .applied v to this )circuit of impulses :of `:coded cur-rentfas applied by ithe f5 cause the polar "contactsof the 'relay yliWLT `to operate to right-'hand positions so that contact A76i completes an obvious'c-ircuit'ior the ener- :gization of the lock magnetjBL as soon #as fthe trainrnani-operates *thelever iL'Hy toits B lposition. The '-energization 'of the lock magnet-6L, releases the handle BLH so that the operator y'can move it to a releasing position. The trainman then manually operates the switch '*Wito its reverse position "for 'the passage -of the train -onto the turne-out track. 'It is to be understood that the operation fof the switch box "contacts and other contacts lvassociated 'with the switch rlock have the saine' functions 'as described. n-cOnnec-r Assuming that the train passes '-'over the track switch Lento the 'turn-out trackand Ithat the Itrainman restores ithe train switch BWfto Iits normal .position as well -as restoring 'the switch llock tov its proper nor-mal condition, @then las soon as the krelay SWL? `.picks xup, :energy lis supplied `from the `.positive side foi' fbatteny '52, over lthe lower =rai1 of lthe track .sectionI GTG, through 5front contact 53:01? relay release track sectionrSTB, front `Contact 1511 .of relay `SVLP, polar Contact, @525 -i-n a Vniglrt-lhand rposition; upper Ywinding Iof relay GWLT, through the upper rairlof the track section STC, tothe negative :terminal of batte-ry 52. iis in ithe-form ,code transmitting relaylSCP.. The iirst impulse will .cause the lcontacts oi'the relay i-SWET to 'be operated to `left-hand positions. this connec- -.tion,v 'it is to `be .understood lthat if the Jcircuit'.

`lshould be closed 'Iorifthis relay 'near the end iof :an impulse, :such impulse-might lnot operate lthe polar .contacts of :the vrelay :"SWLT, 'but lthe 'iirst impulse which .is :su-.fiiclently complete to :supply :the :proper 4amount :of :energy for such relay; will :operate-the .polar contacts :of this relayto thei-ropposite positions. Also,ra lpolarized relay -oi the ltwo-.position typeY is iso constructed that its conatacts Will not remain in intermediate rposi-tions, so that impulse fis applied lthroughlits own contacts 155 in .s uici'ent :amount of energy fte oper- .ate the relay, .its contacts :move :to their #opposite positiorisEa-lthough fits energizing circuit, inayiin the meantime loeinternupted As Vsoon as the contact 55` is operated-to the lefitfhand position, the normal `condition of Ithe Atrack .circuits is restored Iso i that 'the coder 'follow-- ing :track relay .ETR will receive the lcode as :applied to the track )section SGT `by thel'code 'transmitting contact 5| of relay GCP. The signal 6 4is thus `caused to indicate-clear, .assuming `that .there is no .train in the :track sectionIT inadvance of the signal J. .It is noted that thesame `protection is provided in this form of the .invention in the event :ofithe break-.down of insulated joints as :described :in connection with Eig. 1. .Molteispeciical-ly, if the insulated ,jointiz loreaks down. thisy does :not

be released fby the relay f joint 6 2 brokenv down as effected through the restoration circuit including iront contact 54 of relay BWLP, and polar contact 55 of relay BWLT, the` signal 6 would be held at stop inasmuch as the normal completion of the track circuit through the section BTA re quires the polar contact 55 to be in a left-hand position.

If the insulated joint 63 breaks down, then it is obvious that the release rail section GTB is connected to the upper rails of the track sectionf' BTC and energy is shunted away from the code following track relay GTR. This causes the signal 6 to remain at stop and thus the failure of insulated joint 63 becomes self-betraying.

The breaking down of the insulated joint 64.A

also completes a shunt for the track section GTB through front contact 54 of relay BWLP, polar contact 55 of relay SWLT in a left-hand position past the broken-down insulated joint 64 to the upper rails of the track section BTA. This shuntf the switch lock of the present invention is pro-,A

vided with release circuits organized on the closed circuit principle.

In this way, a release track section and its associated control circuits for governing a switch lock have been provided in a manner which is equally applicable to coded track circuits or conventional normally energized track circuits. l While certain features of the invention are applicable to and usable withl any type of signalling system, whether obtained by line wire control or some form of coded track circuit, the speciiic embodiments of the invention illustrated shows the invention applied to one direction signalling, but the invention should be considered from its broadest aspects and not limited for use with such a specific form of signalling.

Having described a system of switch lock control in two diierent speciiic embodiments of the present` invention, it is desired to be understood that these forms are selected to facilitate in the disclosure of the invention rather than to limit the number of forms that it may assume; and it is to ibe understood that various modications, adaptations-and alterationsmay be-applied to these specic forms shown. to meet the requirements of practice without in any manner departing from the scope of the present invention except as limited by the appended claims.

What I claim is:

1. In aV system for protecting hand-operated track switches on railroads, a manually operable track switch, manually operable locking means for the track switch, an electric lock acting when deenergized to prevent manual release of `said locking means, a time element device operable:

when manually initiated for energizing said electric lock only after a predetermined time, a normal-ly closed track circuit associated with said track switch and including a release Vrail normally connected in series therewith, a signal for governing traiic over said track switch and controlled to indicate clear only when said track circuit is energized, a track relay associated with said release rail, means for opening said track circuit to cause said signal to indicate stop and for connecting said track relay in seriesi'with said release rail and a portion of said track circuit to thereby effect the energization of the track relay when the release rail of the track for at times effecting the energization of l said Y electric lock when said track relay is energized.

2. In a system for protecting hand-operated track switches on railroads, a hand-operated track switch, locking means Anormally acting to iprevent manual operation of the track switch, a normally energized track circuit associated with said track switch and including a release rail section normally connected in series with such track circuit, a signal governing traffic over said switch in accordance with the energized condition of said track circuit, means for at times opening said track circuit to cause said signal to indicate stop and for connecting a series track relay in series with said release rail section and the remaining portion of said track circuit to thereby eiect the energization of said series track relay when the release rail section is occupied by a train, and .circuit means controlled by said series track relay for at times causing the release of said locking means.

3. In a system for protecting hand-operated track switches on railroads, a manually operable track switch, an -electric lock normally deencrgized and acting to prevent the manual operation of said track switch while deenergized, a normally closed track circuit section associated with said track switch and including a release rail section normally connected in series with said track circuit,'a track relay located at the entrance end of said track circuit and normally energized over said track circuit from a source of energy located at the exit end of said track circuit, a signal governing traffic into said track circuit and over said switch, said signal indicating clear only providing saidtrack relay is energized, a series track relay associated with said release rail section means for at times opening said track circuit to deenergize said track relay -and at the saine time connect said series track relay in series with said release rail and the portion of the track circuit adjacent said switch to thereby effect the energization of said series track relay from said source of energy if the release rail section of the track circuit is occupied yby a train, and circuit means for energizing said electric lock to release said ,trackswitch only providing said series track relay is energized, whereby said track switch cannot be released by said series relay becoming energized unless the,

providing such-track relay is energized, a source' of energy at the exit end of the stretch connected across the rails thereof, insulated joints included in one rail of the stretch for separating a release rail section from a forward portion of the stretch and a leaving portion of the stretch, an insulated joint in the other rail of the stretch adjacent the release track section and effective to divide the forward portion of the stretch from the leaving portion of the stretch, circuit means normally-effectiveto connect said release rail section andv saidforward and leaving 'acme-4 ,portions of the 4stretch linfa fmanner 'v'.toprovide :normally energized V:track vcircuit :including said :track yrelay :and said-source with :a cross-connection between the two tracks at .therrelease rail insulated joints `providing fthatv the break-down of the insulated .joint .in either track eiects :a -l'shunting of the :track relay, va series' track relay `associated with said locking device yadjacent 'said switch, and circuit means at times :effective to -open said track circuit -at said -release track sec- -tion and to connect said series 4track relay in series with-saidrelease tracksection-and said -leaving portion of thestretch-t'o thereby -ele'ct 'the deenergization of :said ytrack relay adjacent-said `signal and permit Vthe energization fof said series trackvrelayfrom said source of energy when a train occupies said 'release .track section, and

lcircuit means governed .by said series :track re- -lay f-orat times Irelea-sing said locking device-as'- sociated with said track switch.

5. 4In :a system vfor protecting lhand-,operated track. switches on railroads in coded 'track :circuit -territory,ia manually operable track switch, a locking means normally effective .to prevent -manual operation of vthe track switch, circuit ymeans eiective to-.divide-a coded track circuit into a forward -portion land a leaving ,portion with an intervening release, track `section -but normally connecting --all' ,three portions -of- -the coded .track circuit-inrseries, said means at times acting to open said track circuit at said release track section to prevent the transmission of code impulses through said forward section and at the same time render a switch lock track relay responsive to the coding impulses in the leaving portion of the track circuit only when a train is occupying said release track section, and manually controlled circuit means for releasing said locking means when said switch lock track relay is energized.

6. In a system for protectingv handfoperated track switches on railroads' a manually operable track switch, a manually operable switch locking means for the track switch, an electric lock acting when deenergized to prevent manual release of said switch locking means, a coded track circuit associated with said track switch and having code transmitting means at the end adjacent said track switch, a code following track relay at the other end, and a release rail at an intermediate portion of said track circuit suitably insulated from the rails of the entering and leaving portions of the track circuit, a code responsive means 4associated with said release rail, circuit means normally eiective to connect said release rail in series with said entering and leaving portions of said track circuit but acting when actuated to disconnect .said release rail from that entering portion of said track circuit including said code following track relay and'to connect said code responsive means in series with said release rail and that leaving portion of said track circuit including said code transmitting means, to thereby provide that said code responsive means associated with said release rail will effectively receive code from said code transmitting means only when a train occupies that portion of the track circuit including said release rail, and circuit means governed by said code responsive means associated with said release rail when it is effectively receiving code for at times effecting the energization of said electric lock. l

7. In a system for protecting hand-operated track switches on railroads, a manually operable track switch, a manually operable switch locking .zm'eans :for the ftra'ck switch, 'an :electric ,lock enorimally acting while deenergized tio-aprevent 'man- `ruaLrelease `of said lockinglmeans, 1a track .circuit vassociated 'with said ytrack Vswitch :and including fa battery at the end adjacent said 'track'switch, v'a track relay 'at the other .end and .a releaserail at an intermediate portion of the `track circuit in :a .facing point )position with respect to said switch and insulated from-the other rails vof the .track circuit by insulated joints, :a -series track relay associated with :said .release rail circuit means normally effective to connect said yrelease rail yin series in fsaid :track circuit lbut-acting-at "tothe-r times -to disconnect saidrelease yrail from :said `track circuit --at its -end nearest said track relay and also to connectsaid series track relay -in series with `said .release rail and .said track- .circuit at its :otherfend adjacent the track switch, 'to thereby provide for the eiective energization of saidl'series track .relay when the portion of the Vtrack circuit -including the release rail is cocupied by a train, and circuit means including a front contact of said Seriestrack -relay fors-at timesl-,energizing-said electric lock toallow man- `ual release fof said switch lockingmeans.

8. In a system .for protecting :hand-operated -:track switches on railroads, a track-sectionln- -cludingl a track switch;atonefend--and asignal at -the other end, the two -:rails of saidsectionform- .ingfa track-circuit having fa-track battery at the end y:adjacent the trackv :switch and ,fa -track relay at the end adjacent said signal, and a release portion at an intermediate point with its rails insulated from therails of the rest of the track circuit, a series track relay associated with said release portion of said track circuit, circuit means normally effective to connect said release portion in series with said track circuit, said connection at its end nearest said signal acting' to connect the two rails of said release portion to the respective opposite rails ofsaid track circuit nearest said signal, but acting /when actuated to disconnect said release portion from said track circuit adjacent said signal and at the same time connect said series track relay in `series with said release portion and said track' circuit adjacent said track switch to thereby eiect the energization of said series track relay.

when the release portion of the track circuit is occupied by a train, circuit means for governing said signal in accordance with the energized condition of said track relay adjacent said signal, an electric lock acting when deenergized to prevent operation of said track switch, and circuit means for effecting the energization of said electric lock when said series track relay is energized,

f whereby the inclusion of said series track relay in series with said release portion and said track circuit adjacent the switch acts to prevent the energization of said track relay at said signal for holding said signal at stop.

9. In a system for protecting hand-operated track switches on railroads, a manually operable track switch included in a stretch of track, locking means acting while deenergized to -prevent manual operation of the track switch, means fordividing said stretch of track into a track circuit having entering and leaving portions sepa-` V rated by a release rail section in a facing point position with respect to said switch, normally closed circuit connections for connectingsaid release rail section in series withthe entering and leaving portions of said track circuit, code transmitting means at the exit end of the track circuit for applying distinctive code impulses of a particular polarity to said track circuit, code receiving means at the entrance of said track circuit responsive to the diierent codes received for governing the entrance of traic into said stretch, a double wound series track relay of the two position polarized magnetic stick type associated with said release rail section and normally lassuming a particular polar position, control means for at times opening said normal circuit connections and connecting one winding of said series track relay in series with said release rail section to thereby prevent the energization of said code, receiving means and to permit the energization of said series track vrelay to an opposite polar position by said code impulses of said particular polarity when the release rail section is occupied by a train, circuit means governed by said series track relay when energized to said opposite polar position for releasing said locking means, and restoration circuit means temporarily eiective upon the restoration of said control means to effect the energization of another winding of said series track relay by said code impulses of said particular polarity to cause its operation to said normal polar position, the contacts of said series track relay in their normal positions being included in said normally closed circuit connections for connecting said release rail section in series in said track circuit, whereby said track circuit is restored to normal conditions for operation of said .over said switch in a facing point direction, a

track circuit associated with said switch for controlling the indications of said signal in accordance with the energization of said track circuit from a source located at the exit end of the track circuit, a switch lock track relay associated with said locking device, circuit means effective to divide said track circuit into a forward portion and a leaving portion with an intervening release portion but normally connecting all three portions of the track circuit in series, said circuit means being manually controllable to open -said track circuit at said release portion to prevent the flow of energy from said source in said forward portion and at the same time render said switch lock track relay responsive to energy received over said leaving portion from said source only when a train is occupying said release portion, and circuit means for at times energizing said locking device while said switch lock track relay is energized.

THOMAS JOSEPH JUDGE.

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