US1794544A - Train control - Google Patents

Description

March-3, 1931.

N. D. PRESTON TRAIN CONTROL or'igirial Filed July 23, 1923 5 Sheets-Sheet l' NTO Nodi

N. D. PRESTON March 3, 1931.

TRAIN CONTROL Original Filed July 23, 1923 3 Sheets-Sheet 2 Mgrch 3, 1931. N. D. PRESTON 1,794,544

TRAIN CONTROL Original Filed July 23, 1925 3 Sheets-Sheet 3 To Brake 1 Pipe To Engneer's l 14 v Brake Valve I ga l'llI-n'- To Brake Pipe IN V EN TOR.

Patented LMar. 3, 1931 vUIWTE'D STA-ras;

NEIL' n rnEsToN, on nocnnsmnnjivnw vonk, .Assieiton 'ro GENERAL RAILWAY SIGNAL coiviraivv, or nociinsmnneitnw Yom;

applicati@ fnea ,ifuiyv 2e, i923, serial No.' 653,358.' Renewed March' 25, i927.

This invention relates to automatictrain coutrolsystems for railroads.

In applying automatic trainfcontrol to I t Y '.limitingspeeds, if rigidly enforced and if railroadait is believed to be important to 5 retain as far as possible the safety at pres4 ent afforded by the rcare and vigilancer ofthe engineer, otherwise there Wouldber substituted the runcertain safety provided by automatic mechanism. -If the vigilance Loffthe io,- enneer can be maintained', the ultimate safety ofthe train is doublyassurechbecause be#` fore an accident can occur,'not only must the;y

engineer fail to perform his duties, but also the automatic train control system must fail. il; .lu accordance with the presentv invention,

itis proposed to secure the' continued vigilance on the part of the engineer by providing a suitable penalty lfor his neglect, the

theory being that the engineerWill naturallyv take the'couise of least resistanceand will perform his" regular duties properly rather than assume the penalty. While various methods of penalizing the engineer forhis failure to take appropriate action maybe einployed, it is proposed to` arrangelja system such that a neglect or' failure on the part of the engineer subjects yhim to someextra trouble or annoyance, making it an ob]e'ct forhiin to watch out for theindications ofthe lblock a signals and obey them. y'

LWhen it comes to deterininingthe character of the automatic control to beprovided, there arises the question of compromising between safety and facility of `train movement. From thestandpoint of obtaining a high degree of safety With the 'least Vinterference `ivith train operation, it is consideredto be preferable to employ a speed control system, providing a plurality of speed` limits for different points in a caution block 'and automatically applying theibrakes `in the event that thesespeed limitsare exceeded.; "In the practical application of such l, a system .to railroads, however, on account of the var lation in the length of the blocks, the varied braking power and stopping distance' of trains, dierent grades., and othenconditious, it becomes diflicult,y if not impractical, to provide for every block and at every point.' in the travel of a train the speed limit Which is safe `and Will-v delay-train'movement tothe minimum.;Consequently,fforv certain blocks and under certain conditions, the curve or line of the-train is required to always run at-speeds -beloiv this cu'rve,vvvill introduce serious delay.

In View of these considerations, enforcing vigilance by penalizing the engineer for'his ffueglectand the inaccuracies of speed limit ing curves, it is proposed in the present invention yto make it possible forthe train to rim at higherspeeds than required by the automatic equipment'andretain vigilance by requiring the' engineer. to initiate, before Aex ceedingjthe prescribed speed limits, an effective brake application,complete this "ap- .plication and maintain it so long as the speed :isi excessive `and traiic'conditions demand continued'retardation of the train. Itis v`cimsidered to be a simple and advantageous expedient vto require theengineer to manifest his alertness and vigilance by initiating a .manual brakea-pplication, not only because ,such brakeapplication'- and slowing down of the train is the best and safest thing to do 'under. the circumstances, but also because the means by Which the engineer israble to fore- :stall the lpenalty is such thatV it Will not be abused.Y i Y t Generally speaking, this invention contemplates an organization of devices which, inthe first place, Will result in anV automatic tain points along thetrack are exceeded, enforcing a penalty if this automatic brake ap- 'plication occurs Without appropriate action on the Vpart of the engineer, and in suppressing this penalty but not interfering with the regularvoperation of the automatic `brake yapplying' equipment,'i'n case the engineer is -j While the speeld limits above mentioned may-,be obtained in various manners, and may be continuing in their effect until changed,

application of tliebrakes and slowing down c yof the train under dangerous traiiic condi- .tions if predetermined speed limits at VcervCfr .types of speed centrol Systemsnnd, in fact, in various arrangements ,andV organizations.;

It may be explainedV that the time-distance interval principle has beenv selectedforthe. vpurposes of illustration in this particular instance, because such type v4is more capable ot adaptation or adjustment in a simple fashion to lit the varying requireinents'as to speed limits `for the diii'erent blocks and diii'erent parts ot the railroad. f ln vaddition to the general principlesand underlying features ofthis invention, various other characteristics, advantages, and principles of operation will kbe pointed out hereinat'ter as the description progresses.

In the accompanying drawings, Figure l illustrates in a simplified and diagrammatic inanneigusing in many respects established conventions, the car equipment and circuits constituting this invention, also' one of the track elementsor inductors in itsv cooperative position with the car-carried receiver;

Fig. 2 is a diagrammaticfview showing the trackivay equipment and illustrating typic -al speed limit curves and train performance curvesg'and y I Fig. '3 shows a inodied construction ot the automatic brakeapplication valve.

Tmccwag/ equipment-In the form illustrated, it is proposed to communicate the desired control influences from the'trackvvayV to 'the moving car, dependent upon traine-conditions in advance, byan interiniftt'ently acting` inductive means Working WithoutV physical contact through an intervening air gap, such influence communicating means broadly consisting oi' a car-carried receiving element and track elements or inductors to cooperatetherei-vith. The track elements or inductors have their operatingcondition governed in accordance with tratiic conditions; 'and While this requisite may be lsatisfied in various Ways, vand While various specific forms of control circuits for .these inductors may be employed, in thetypical arrange-ment shown in Fig 2, the track railsl are divided byv insulated joints 2 into blocks in the'usual Way, one block E With the adjacent ends of two other blocks D and-F. The parts and circuits associated Withtlie various blocks are in general the saine; and for convenience these parts for the several blocks Will vbe `'given the same reference characters with distinctive exponents. Each ot the blocks is provided With the usual track battery 3,'.and a track relay il, the same as in ordinary block -dicatedby the arrow). elementsy T comprises a` U-shaped magnetic signal systems and in conformity with established signaling practice. The system is preferably used in connection With the usual fixed signals ot the block signal system; and such block signals Z are slioivn conventionally, Without attempting toillustrate any par# ticular form of control circuits, it being understood that these signals may be any one of the Well-known or approved types and may becontrolled injany onev ot the VWellknoivn ivays.' f

At several points in each block are track elements or inductors T arranged in pairs. rllieparticular point of location of these pairs otl induct'ors and the spacing or distance between the inductors of -cacli pair, will be more fully explained liereinatte `and tor the present it is sutiicieut to note that a speed limit isfprovided at cach pair of inductors depending-upon the spacin ot' that pair.` As illustrated, these indue-tors T are located outside oi' one oi the trackrails on the righthand sifdejof the track with respect to the-,normal direction ot trattie, (from lett to right-as in- Each of rthese track `core of si'iitable'cross-section and preferably laminated, enlargedpole kpieces 6, and a coil .c

i' on the back yoke of said core. At each pair of inductors T is a control or line relay v8, and these relays 8 oi each block vare connected across line wires 9 and i0 Which are energized from Va. batteryll when t-he trac relay of thev block next iii-advance 'is energized. wWith tlieline relay 8 energized, the

vcoil or 'Winding v7 :of botli'or thesecond in- :ductor of 'the corresponding pai-r is connected in a closed kcircuit of low resistance including `Wires` and`18 and airont Contact 1G' et said linegrelay.

It, is statedhere that, tor lthe purposes oil economy, the inductor ot each pair lirst'encountered by a train is pret'- erably ank iron core Without any coil, only the Vsecond inductoi ot each pair being provided ivith a Winding controlled by the corresponding line relay 8. 'It will be apparent tliat'wlien a block is clear (no train in the ner-t block in advance), the lin'c relays t are Aenergized andthe second inductor T ot' each -pair has its coil 1' closed in a circuit ot low resistance; Whereas if the block is a. caution `block due to the presence ot 'a train in the next block in advance, the line relays 8 are deencrgized, and the coil T on the second Yinductor ot each pair is on open circuit.

ifso

' over the. 4track inductors '.l.

i 'the valverelay VR mined time interval.

natedl core 20, with .enlarged pole pieces 21, Awhich is suitably .carried on the locomotive or othervehicle `infposition'to pass directly On oneleg of the core 2O is a primary winding l,J and on they other leg is a secondary Winding S. As indicated in Fig. l, the car-carried receiver Rcomes in superimposed relation to the successive track -inductors T With a small air gap intervening` between the pole pieces of these respective devices. These track inductors and the car-'carried yreceiver are, of course, located so as not to interfere With the trackivay or rolling-stock,clearances; and they air gap between is preferably fenT inches above the top of the runningrails.4 Y

The car apparatus includes a: numberlof relays which are, of course,` suitably constructed toperform tlieirparticular duties. There is a primary or control relay CR connected to and controlled .byzthe receiver R in the manner hereinafter explained; a repeater relay RR; a valve relay VR; a penalty relay P; and a check relay CK. Since-these various relays are carried upon the locomotive or other railway vehicle and are consequently subjected to jar andvibration, theirmoving partsare balanced inl addition to other provisions that Imay be-found expedientk to `avoid `false operationl due to jvibration. Consequently,'the armatures or contact lingers of these relays-are shovvn' as of. the balanced or central pivot type, biased from the horizontal to the'inclined position by suitable springs or the like. lOnvaccount ofV theparticular cir'- cuitarrangement employed, the repeater relay RR and vthevalve relayVR are providediwith four contact fingers; and for the samey reason isshovvn as having tWo windings. v f j Another part of the car apparatus is a time element device TE, the primary function Vof which is to open a circuit, When'operated, and maintain this circuit open for va predeterthis time element device consists of abalance wheel 22von a freely turning shaft 23 which is biased to a predetermined intermediate position by a spiral spring 24. Fasten-ed to the balance Wheel 22 is anarinature 25 arranged to move into attracted position with respect to' the pole piece 26 of ay releasing or starting magnet 27. f The shaft 23 is arranged to openand close certain contacts in different positions; and'for simplicity of explanation and to facilitate understanding the operation, these contacts are shown conventionally rather than in their structural form. `There isa contact arm 28 on the yshaft 23 arranged to 'Wipe' over a stationary contact 29 after the shaft 23 has turnedclockvvise (as indicated by the arrow a) from the normal position shown. Another contact arm 30 engages a fixed Contact 31 While the shaft 23 isin the normal position and for a certain angle of In the form illustrated,

rangement shown is a pneumatic valve, electrically controlled, which for convenience is designatedas a Whole the application valve A.

This applicationvalve A 'is intendedto cooperate With or act upon an automaticairbrake system ofthe usual type and produce automatically a service application of the brakes, at the same time preventing the engin eerk from opposing this automatic appli- `cation or checking its effect. This application valve A comprises a suitable air-tight casing 32, Which will, of course, in practice be made in parts with suitable joining"gaskets-v for ease in manufacture and inspection. In

the casing 32 is apistoii 33, with a leakage'hole 34 therein, Av'vhichisy connected in thefusual Way to a slidevalve The 'piston 33' is urged to the righthand position shown bya spring The'lefthand side of the piston 33 is connected toa suitable electro-pneumatic valve EPV Which, Whenever its coilsy 37 are deenergized, 'opens and exhausts to' atmosphere-J This electro-pneumatic valve, which.

issliown inasimplilied form, is constructed in accordance with recognized practice, and

in-additiontojcontrolling `air pressure, has i' contacts '38, conveniently termed stick contacts, which are closed While itsscoils 37 are energized and are automatically opened upon deenergization thereof.. The valve casing32 on the righthand side of the piston 33is connected by pipe 39 to the usual main reservoir ofthe air-brake system.

This device may.V take various forms, butin the particulargary `1 1T he port Il() is piped to the engineers brake valve and constitutes the sole source of supply` of main reservoir pressure to the engineers brake valve.4 This port 40 is open with the application valve A in the normal position shown, so that ythe engineers brake valve is suppliedwitli main reservoir pressure; but

upon operation of the application valve and movement of the slide valve 35 tothe left, the port 40 is blanked, and the supply vof main -reservoir pressure to the engineers brake valve cut oil", so that the engineer-can not attempt'to recharge the' brake pipe, AWhile at` the same time he is free to exhaust thel brake plpe.'

Forming a part ofthe application valve A, preferably enclosed in the saine casing, is

an equalizing piston 4l and discharge valve 42 corresponding to that contained in the lower part of the regular engineersbrake valve. The underside of the piston 41 is connected at 7 7 to the brake pipe. The upper side of this piston is connected to a small reservoir'ER, preferably ofthe same size as the regular equalizing reservoir of the air- VSo long vas` the `electro-pneumatic valver EPV is energized and closed, main reservoir pressure equalizes through the feed hole on opposite sides of the piston 33, andthe spring 3Gfovercoming-friction forces said piston andthe slide valve 35 to the extreme righthand normal position shown. In this position the 'engineers brake valve is supplied `with rmain reservoir pressure through lthe port 40, and thev reservoir ER, and both `sides of the equalizing piston 41 are subjected to brake pipe pressure. The other ports of the slide valve 35 rare blanlred.

i Whenever the electro-pneumatic valve EPV is deenergized and opened, itexhausts pressure from the lefthand side of piston 33 faster than it can be supplied vthrough the feed hole 84, whereupon the pressure on the rilghthand side predominates and shifts the slide valve 35 .to the lefthand or operating position. In this position, the port 49 is blanled, preventing thev engineer from opposing theA automatic application,` or releasing thel brakes so long asthe application valve is in this operating condition. The cavity 44 disconnects the reservoir EPy .and the upper sideof lthe equalizing piston V41 from the brake pipe and connects theml to a restrict-ed exhaust port 49,1Which preferably has thesame area as the preliminary exhaust port of the regular engineers brake valve, assuming theireservoir ER- to rcorrespond in volume to the regular equalizing reservoir, it

being understood that the sizeof the exhaust opening 46 and the volume .of the reservoir 'ER have the same relation as the corresponding parts associated with the 'regula .I airbrake valve, so that the pressure in reservoir ER Will drop at the same rate. The cavity 47 in the slide valve 35 connects the pipe 4 i, leading to the exhaust of the discharge valve 42, with pipe 49 leadingrto a suppression valve SV hereinafter described, the pipe 49 being connected to atmosphere until the suppression valve SV has operated because@l predetermined reduction has been made in the pressure' of the regular equalizing reservoir, as explained hereinafter.

Referringl now to the suppression value Si. it may be explained that this device is intended to operate only if a predetermined reduction, such as twenty pounds, has been made in the normal running cqualizing reservoir pressure. In other Words, this suppression valve SV operates when a predetermined bralze application, preferably a substantially fullservice application, has been made, at least so far as the equalizing reservoir is concerned. In the form shovvm'the suppression valve SV comprises acasing 50 which contains a pistou 5l, z slide valve 52 and a. spring 53. The piston 51, While provided With the usual ring to give it as tight per square inch on opposite sides of the piston 5l, the strength of this spring de lending uponv the kamount of reduction at .which it is desired 'to have this device operate. The righthand side of the pistou 5l on which the spring 53 acts is connected by pipe 54S to the regular and usual equalizing reservoir of the air-brake system. The .lefthand side of the piston 5l and the chamber above the slide valve 52 is connected to a pressure reservoir 57 which has a connection to the brake pipe controlled by an electro-pneumatic valve 58,

thisconnectiou to the brake pipe existing While said electropneumatic valve 58 is energized. but ceasing as soon as said valve 1s dcenergized.

The slide va ve 52 has a cavity 59 therein Which connects the pipe 49 leading to the application valve fr to an exhaust port. lith the slide valve 52 in the normalposition sho\vn,.a cavityGOconnects to atmosphere a pipe 6l leading to an air switch AS. This air s vvitch AS comprises a-piston 62 urged inward by a spring 63 and a rpiston rod V64cm'- ryinginsulated contactmembers 65 arduo. The piston 62 is preferably of the trunk form shown, and when forced outward in opposition to the springr 63 seats against a gasket 67 to form an air-tight seal, so as toprevent leakage from the pipe 6l. f.

4'For the purpose of controlling the suppresgsion valve SV andalso for use in connection Yonly in the running position of the brake valve; another pair of contacts 71 closed only in the service (and alsoif desired, thel emergency) position of the brake valve; and a pair of contacts 7 2 closed only in the release position of the brake valve.

The operation of the suppression valve SV may be conveniently discussed at this time. preparatory to a description of the operation of the complete system. Vith the engineers valve in the running position and the contacts closed, the electro-pneumatic valve 58 is energized by acircuit that can readily be traced yon the drawing. It may be eX- tif/@etai gplained `here 'that for simplicity the circuits :shown in F l yhaveA been illustrated-in ac;

:co'rdance with established vconvention kaster-` iiiiiiating vwith B C,yi"epresentiiig'` Vcon.- ncctions to' the'opposite,terminals yot a bat-y tery or othersuitable source oifrcurrenti ilil'i'tlh 'tlie electro-pneumatic'valve 58'eijioi'giiie'1 and open, the pressure vreservoir d ectly connectedvto v'the biallzepipe and kthepressure therein correspondswith the normal running brake pipe pressure, ii/'lietlier that be 'TQQO or 110 pounds, andfirrespectiveot the par-l ticular settingv of the feedvalve. rlhe pres! sure inthe equalizing reseifcoiris, course, the saine, since the braire pipe aiidjtheeqiial! izing reservoir are connected togetherA when the engineers valve is inthe running position.,4 Consequently, the pressures on the opposite sides of the piston 5l are equal, and this pis! ton is'liorced to and held in the leith and posi,- tion shown bythe spring 53. l

l/Vhen the engineer moves his brake -Valve to the service vposition to make ainanual brake application, `the contacts open, the electropneuinatic'valve 58 fis deenergized'and closed byits iisiialspring', and the normal running brake pipeA pressure therefore trapped y in the-pressure reservoir 57., fterthe engineer has ina de a predetermined. reduction in equal izing' reservoir pressure, which willin time result in a `corres'poriding brake application, the pressure on the'lefthand side of tlieypiston 5l, or rather `the area thereof exposed within the ribonethe tace seatedagainst the h'zislzetli, becon'ies greater than the eqiializn ing' reservoir pressure pliistlie strength of the .s rin0153. Theainoiint ot reduction ine uali s e,

izing reservoir pressure necessary to bring aboutthis condition ispreterably selected to correspond with a 'full service application, or ai'iproxiinately a twenty pound reduction. As soon as the `pressure on the lefthand side ot the `piston 5l .predomina-tes, it moves 4to the right, the gasket .seal is broken, a greater area isexposed on the leicthand side,`and the piston shifts quickly to tlierighthand position. In the riglithand:positionthe area eX-y posed diie to the seal ot the gasket 55, is re;

duced, and the piston is held in this position with a ditlerential oi pressure large enough to assure an air-ti prevent lea a rbt oint with ysaiiil gasket and When the piston :Bland the slide valve 52 i sliiit troni 'the normal" leftluind position shown to the riglithand position, the pipe (ill is .disconnected vtroni atmosphere `and connected to apipe 68 leading to the main lreserioir :and pressure isiadmitted'vfroin tliemain reservoir tothe air switch AS, forcing out its piston 62 and closing the contactsj and (36.y This movement ot the slide valve 52 alsocuts j the pipe i9 from its norinal connectionto y l frontcontact and `larmature 83 of said relay to B. When theifreceirer'R passesv over atmosphere.'

,Y l, suppression i Valve SY is essentially a'de'vice Whichjopeifates only after a predetermined `reductionhasbeen made in the normal running :equalizing reservoir pressure. This Vreductien niayftale piace in one or several stages-,ii'ith no ,difference iii the resultant eifeet.y rllie act-ion is independent Aol" the actual val'uejofj the fbralepipc pressure. ,This sup-v pression'walve S'\7,7i\lien it operates, closes Vthe mannernot-shown, to the car wheels and acting; to close contacts fl when the speed olf thecar isbelow said minimum speed. i

In conformity with the principles hereinbefore stated, it is proposed to penalize the eng' ieer .tor his failure totake appropriate act-ion and in the particularorm of the invention illustrated, this penalty is provided by requiring the engineer afterhis failure, to operate a reset switch RS.L This reset switch]RSSisjprefererably located so as to` be vaccessible, only'from the ground, yso that the train has tobe stoppedhetore said switch can beoperated. n rEliisji'eset switch BS may, if, i desired, be located in a locked or sealed box or equipped'with a recorder. ln the simpliiied form shown, this reset switch RS coinprises twol switch arms and 76 operated simultaiieously from the noiinalposition shown in full lines to the dottedrposition. By reason ofthe electrical connections, this reset switch'rcan not be'fastened in its resetting position :without detection, since thehrakes can not beieleasedto permit the train to proceed with the reset switch in its operated position.

pera.imi.-The operation oi the systenion this invention is more `conveiiientlytaken up in .steps first and then the operation as a w iole und er the operating conditions .eiicocin tercd in practico briefly suniinarizedil yThe impulse communicating n'ieai'is operates in the following manner. The prima-ry coil P oif the car receiver R is normally energized a circuit which may be readily traced? on the drawing, this circuit inciudingra cheol:

ary coil S is connected in series witlia normally energized stick circuit for the relay CR as "follows z-coimnencing at C, secondary' coil S, wire v80,'relay CR, wires 8i.l and track iiiductor T having no coil or with the coil on open circuit, there is al change in the flux produced by the primary coil P through thesecondary coil S, pioducing an induced voltage, lirst in one direction and thenr in the other, which acts to deenergize the control relay CR. As soon as the armature 83 of the relay CR is retracted, its normally closed stick circuit broken; and consequently even through the induced voltage in the secondary coil S is only momentary, the relay remains deeiiergized.

1f the coil 7 of the track inductor T is closed at the time the receiver R passes over said inductoi', this coil acts to oppose or choke back the passage of flux through said inductor, with the result that the voltage in,- duced in the secondary coil is much reduced and is insuficient'to cause operation oi the armature of the relay CR.

Thus, each time the car passes an inductor without a coil or having its coil on open circuit, the control relay CR is deenergized and remains deenergized. untilV otherwise restored,

but if the coil 7 of the track inductor is on closed circuit, the relay CR is not operated.

Speed limits-Each pair of track inductors acts to produce a control upon the car dependent upon the speed of the car at this control. point. This speed limit depends upon the spacing of the inductors of the pair and is due to the following operation ofthe carr-VV carried relays and the time element device.

When the car passes the first inductor, and

, the control relay CR is deenergized, a normally closed stick circuit :tor maintaining the repeater relay RRenei-gized is interrupted, this circuit being traced as follows commencing at B, armature of therelay RR, its contact linger 84 and front Contact, Wires 8.5 and 86, relay RR, wire 87 and insulated front i contact 83a of relay CRto C. The deenergizatioii of the relay RR .causes its Varmature and contact fingers to shift to the position indicated by the dotted lines, resulting in the opening oli said stick circuit at the linger B through linger 88 of the relay RR, wire 89,

upper winding90 of relay VR, Wire 91, liront Contact and linger 92 of relay VR .to C. At the same time'that this stick circuit for the .valve relay VR just traced is broken, an

alternative stick circuit is established as,v folklowszffrom B to the linger 98 and back contact of relay RR, Wire 9st,normally closed centacts` 30751 :of the time element device ,..TE, wire 95,lower winding-9G ot; relay VB,

wires 97 and 98, front Contact and finger 99 Aof relay VR to C, ylvhe contact lingers 88 and l tact, Wires 100 and 8,1, relay CR, Wire 80 and secondary coil S to C. After the control relay CR has been reeiiergized, and also after the shaft 23 of the time element device has turned through a few degrees from its initial position, the pick-up circuit for the repeater relay BR is 'established -coininencing at B,

contacts Q8-29 of the time element device,

wires 101 and 86, relay RR, wire 87 and insulated lingers 83:'l of" the relay CRA to C. The contacts 28--29 are so arranged as to close long enough before the contacts 30-.31 open to permit the relays CR and RR to pick up their armatures. As soon as the relays CR Yand RR are again energized, they are main tained energized by their stick circuits here tofore traced, and similarly the valve relay VR- has its Winding 90 maintained energized so that subsequentopening of the contacts S30-31 of the time element device produce no effect.

Fromthe foregoing explanation, it can be seen thatthe organization of circuits including the valve relay VR is such that, upon the reception of the lirst impulse from the traclc way at the first inductor, the partsbeing in the normal condition, this valve relay isV maintained energized; and except for the starting of the time element device, no change has been effected'in the car apparatus.

Upon passing the second inductor of a pair, in its active stopping condition, the el feet upon the car apparatus depends upon the speed of the train. In the first case, if the speed of the train has been below the prescribed limit, there has been time enough for the balance wheel 22 of the time element de vice to return Vto its initial position shown and be locked by the magnet 27, before the control relay CR is deenergized at the second inductor. Consequently, at the time the control relay CR drops, the relay RR is energized and the time element device is normal,

lso that; the saine'cycle of operation as hereinbefore described takes place with no effect upon the valve relayv VR and merely starting another operation of the time element device. I'n the second case, ifl the speed 0I" the train isabovetheprescribed speed limit,l then the time. taken by thetlain in'. traveling from the first, ndiicter Ofi the pair-to the second, i11- ductoris less than tlietiine interval-forwhich j tiras @leUOe-.rit-v device is. ser; and at the 3 licity, and is penalized to that extent.

instant the control relayaCR is? 4dropped Y the second inductoigrthe'itiinev element ydevice. willnot have returned tofiierinal and contacts --31 in particular will be open. Referring? tothe effect of the seeondiin'pulse, the'control relay GR and"tlievjrepeaterlrelay RR- are dropped thesaine asbefore; but when the' relay RR idrops, fthe :valve'r'el'ay: VR alsoL drops-,because the contacts 30-31are opeii.`

w- Oncethe valve relay VRl is deenc'rpgized, it-

remains deeneroized the-A circuits :throuffli both of its windings 90 and 9G incl. dingfront f contactsQQ'and 99 which areop'ened upon deenergization of thisV relay. Upon .making` 'of l the coiitacts28i29 during the return swingof the balance Wheel 22, the relay RR is ener- Lniized, thecontrol relay CR havinpbeen previou sly `eiiergijized through. the back' 'Contact S8 of saidfrellay RR; The energization of the relay-Rltsupplies current again to theinagnet 27 which catches vand holds the balance wheel Thus, therelays'CR and RR and the vtime lelement 'device are restored to the normal position; rbut the valve-relay VR,"

due totheexcessivespeed,jhas beendeeiierrinht'tiine. lIn this particular instance, the'.`

action required of the engineerto forestall or prevent the penalty consists in initiating a manual brake' application by placing the r'epjl rular engineerls brake' alve in the serv-ice position.y Obviously, the engineer will not have to keep'alertif heinay take this-action after the automatic control has taken-effect; and

4g vigilance on the part ofthe engineer is assured only if Ahe is required to'act prior to the automatic operation, specifically that automatic operation represented bythe' deenergization ofthe valve relay VR Yor the equivalent condition nianifesting excessive-speed.

If the engineer fails to take tiinelyaction in this manner, lie 1s penalized. ln this instance,

thepenalty'consists in reqiiiiiiip,l the engineer K to1operate the reset switch RS in order to t proceed. Ifthis resetswitch RS is accessible only fromthe groiindaiid the train inustfbe stopped before itcan be'operated, will be readily appreciated thatthe engineer has been subjectedito some annoyanceand some pub- 'l y If an antoinaticregister is connected to the reset. switch RS, it Would be? possible to ascertain ivhet-lier or not the engiiieerwas negenergizeclsiibject to the automatic control; due `to excessive speed in the same manner pievik: ously explained. It will be noted that When-,q

lectful, and hecould be disciplined accord To explain the operation of. enforcinga penalty, in accordancefwith tliespec'ific embodiment shoivn, assume first that they en-V lji'iieer is alert" and 'moveshis brake valve etiliandle to thefservice position prior .to .the

deenergizationofthe valve relay 'VR'. v This`r closesan energizing or pick-up circuit forftliey penaltyT relay fl as follows :#-commencingat lf3, contacts -7`1 on theengineers ybrake valveclosedonly in the service positiomwireslOQ and-'103, relay P,'\vii"es '.1045 and `105,' fronty contact-and finger 106k ofthe rvalve relay`l :VR

toiG.-

Vr`l-he penalty relay Pfonce energized, is:

maintained energized irrespective off therdeenergization ofthe valve relay VR',-byza stick circuit asf follows cominencing at fcontactf'lv on the engiiieers hrakeva-lve', Wires 102 and' 103, relay P, Wires 104 and107, front contact and thefcontactrlingerlOS .of relay llt will be evidentthat `the engineer'iiiiistlieep his brake valve in the serviceposition toi maintain `the penalty relay. energized atl least until a predeterminedreduction in equalizing reservoirpressure hasvbeen made i' andthe air switch AS has operated-to close its contacts 65, these contacts with their coii.

nection to Bforming with wre`109 an alter-l l native or multiple. path; for the contact 71.- and jWire 102.'l Consequently, after the prey determined reduction has been made in' eqiializing reservoir pressure, thev engineer. may move his brake valve out of the service posi-V tion to thelap position andavoid useless overrediiction in theipressnre 'of the eqiializing reservoir and brake pipe.

The net result ofthe initiation, completion,v and maintenance of a full service application.

manually by the engineer prior.y to the deenergijization `of the `valve relaygVlti-isv the energifization of the penalty 4relay l),- it beingv possible Withtheielayl) energized to auto# inatically reset the valve relay VR in the inanner hereinafter explained. i

Assuina however,j that the; engineer is asleep or otherwise neglectful kofhis duties and failsto maketimelyoperation 4of his brake valve. is deenergized, the opening of its front contact 106 prevents .subsequent energization of the penalty relayl?, with the resiilt thatthis valve relay VR can only be restored luy-openatioii of the reset switch RS.

Upon operationof the reset switch 35,4111. energizing,- circuit for the lower Winding Ss''of the valve relay VR is established as follows zA commencing at B, contacts 74 of the speedresponsive device 7 3 closed because the train is at rest, Wires 110 and 95, Winding 96, wires 97, 111 and 112, reset switch contact 76 and its back. oontactto C. Jafter the valve relay VR has been reenergized in thisfashion, it is kept ever the reset switch RS is operated toV inove As soon as `the valve relay VR,

Automatic 'brake applications-Each time.

the valve relayVR is deenergized, a normally closed stick circuit fori the electro-pneumatic valve'EPV is opened, this circuit being as folloWsz-cominencing at battery B, `front contact 113 of check relay CK, Wire 114, Winding,-

37. of the BPV, Wires 115 and 116, normally closed contacts 38 of'said EBV, Wires 117 and 118, reset switch contact 75, Wire 119, front contact and finger 120 of the valve relay VR to C.' The electro-pneumatic valve EPV remains deenergized so. long as the valve relay VR is deenergi'zed'.

They deenergization of electro-pneumatic valve EPV results in operation of the application valve, as already explained, to produce an automatic application ofthe brakes. The ventingl ofthe brake pipe by the application valve A continues until the slide valve 52 is shifted, that is, until the engineer has manually made a predetermined reduction in equalizing reservoir pressure. When thisl lattercondition exists further venting of the brake pipe by the equalizing piston discharge valve 42 is unnecessary. Even though the brake pipe pressure may not have actually been reduced to the desired extent at the instant the cut off of the brake pipe exhaust at cavity 59' takes place, it is assured that the desired reduction lin brake pipe pressure Will a; sure uponl automatic operation of the application valve A is determined by the action of y the engineer in effecting manually an equivalent reduction; and if theengineer is incapacitated or fails to make any reduction in equalizing reservoir pressure, it would at first appear that there isno automatic over-reduction, due to the fact that the pressure 1n the rese-rvoir ER continues tol drop and the exhaust from the brake. pipe through slide valve 52 continuesonly untilthe pressures inthe brake pipe and the equalizing reservoir, which are connected together With the engineers valve i in the running position, have dropped tothe point where the slide-valve 52 shifts, but this "ff is not true, because with the engineers brake valve inthe running position the valve 58 is energized and the pressureson' opposite sides of pistoni` 51 arel equal, leaving' the valve 52 inVY itsi-iofrirnjal positionv so. that' the brake p ipe is`- entirely vented whentlie valve EPV is de-l energized with the, engineei"s brake valve in the running position. V i' y Under ordinary conditions, the engineer Will have placed his valve in the servicey position and commenced reducing the equalizing reservoir pressure' Abefore the application valve Av operates, this assuming that the engineer, due to the'penalty, remains alert aiid'puts his brake valve in the service position before the valve relay VR drops. Consequently, under ordinary conditions further exhaust of brake pipe pressure, due to the automatic operation of the application valve A, is cut off assoon as predetermined reduction has been made in equalizing reservoir pressure. o Y

It Will be noted that the port 40 of the application valve A, connecting main reservoir pressure to the engineers brake valve, isclosed when the application valve operates. This prevents the engineer from opposing the 4automatic application or releasing or recharging after such automatic application has taken place. In short, the brakes are applied and remain applied until the electropneumatic valve EPV is reenergized. l

It will alsof be observed that in those cases Where the engineer is vigilant, the automatic operation'of the application valve, taking place while the engineers valve is in the service position and equalizing reservoir partly reduced, brings about venting of the brake pipe at tvvo places, at equalizing piston discharge valve 42 and equalizing piston discharge valve in the bottom of the regular engineers valve. On account of the use of the pistons and a restricted rate of discharge of the pressure inthe ieservoir ER, this venting of the brake pipe at two places does not end to give a quick action or emergency, because the rate at which the pressure falls in the reservoir ER and in the'regularr equalizing reservoir is the same, and the equalizing pistons and their discharge valves act automatically in tlieYWell-known manner to prevent the brake pipe pressure fallingv at a greater rate.

The electro-pneumatic valve 'EPV can not be reenergized until the valve relay VR has been picked up, this being accomplished by manual reset as' already explained or by automatic reset to be. hereinafter explained. Because the valve relay VR may be automatically reenergized, and because it is. undesirable to have an automatic release ofthe brakes, stick contacts are provided for the electro-pneumatic valve EPVl and a shunt therefor, comprising wires 121 and 122 and contacts 72 on the engineers; brake valve closed in the release position. By virtue of sition. There imust be an actual movement ofthe valve .handle by the engineer, otherwise there can beno automatic reenergization of the electro-pneumatic valve EPV. The contactsy 7 2 are 'disclosed as being closed in the release position only, because the engineer in releasingl the brakes ordinarily makes this movement; but it is obvious that separate push buttons, or contacts closedin otherpositions of theengineers brake valve may be employed, if desired. y l

In connection with the operation of avoiding Va penalty, and also'limiting the amount of reductionv upon automatic operation of the application valve, the engineer is obliged, as

already explained, to keep his brake valve in the service position until a predetermined reduction, say twenty pounds, has been made in the eqnalizing reservoir pressure, the slide valve 52 has shifted and contacts 65 are closed.y As an aid to the engineer to facilitate the manipulation of his brake valve and permit him to move it from the service position to the lap position as soon as the'desired reduction has been made, a suitable signal, preferably an audible signal, such as the bell 123, is provided, and this signal is operated by the closing of contacts 66 when the air switch AS operates. The bell 123 is preferably of the single stroke type. With the aid of this signal, the engineer is abler to place his brake valve in the service position, and without particular attention to time or Watching the gauges, is able to tell the very instant it is permissible for him to lap his valve without incurring a penalty. Whenever the electro-pneumatic valve EPV is reenergized after` operation of the application valve A, the pressure builds up on both sides of the piston 33 and the slide valve 35 is returned to the normal position shown, lopening port 4l() so that the brakes `may be released and` connecting up the reservoir ER again with the brake pipe. It may be explained here that the cavity 47v is provided to avoid brake pipeleakage'in case the discharge valve 42should not seat tightly.

Automatic reset 0 f val/Ue relay TTR-It has been explained how the valve relay VR may be manually reset by operation of the reset switch RS. Thisrelay VR may also be automatically reenergized in two different ways, one by the action of the track inductors, and the other bythe closing of the speed contacts 74.

Thel inductors T are arranged in pairs as shown in Fig. 2, and the first inductor of each pair has no winding so thatv it is always able to drop the control relay CR. Upon drop'- ping of the control relay CR, therepeaterrelay RR is likewise deenergized. Assuming the time element device TE to be 1n the nori mal condition, andfurther assuming that the VRmay be reenergized by a circuit that may be` traced as followsz-commencing at B,

contact linger 93 and back Contact, Wire 94 contacts 30 and 31 of the time element device, wire 95, lower winding 96 of relay VR, Wires 97, 111 and124, contact linger 108 of the penalty relay P and its front contacttoy C.

Thus, atthe first inductor of each pair, the valve Vrelay VVR is reenergized, momentarily at least. Having fixed this in mind, it is next in.` orderv to consider the conditions under which thevalve relay VR will remain energized. In the irst place, this relay VR will be deene'rgized kat the second inductor of' the pairifthefspeed is excessive, for the-same reasons 4hereinbefore explained. In the second place, if the second inductor of the pair is in the inactive or non-stopping condition, due to the connection of its coil 7k in a closed circuit of lowV resistance, then the valve relay VR likewise remains energized.y If the speed ofthetrainhas been reduced below the safe permissible limit,the valve relay VR is energized and kept energized; and likewise, if trafiicsconditions have` cleared up since the valvev relay VR was deenergized, then this relayy is energized and kept energized at the next pairv of inductorsencountered bythe vehicle. i n

Separately and independently of the inductorl control just explained, the valve relay'VR may be energized, providing the engineer yhas been vigilant andthe penalty relayP is picked up, as soon as the speed ofthe train has been brought below some predetermined minimum speed, such as twenty miles per hour, and the speed contacts 74 close. The energizing `circuit for the relay VR in this instance is from Bthrough contacts74, wires 1,10 and 95, and through the lower winding 9G andthe front contact of the penalty relay',

the same as in the Lcircuit just traced.' YThe particular purposeland advantage of restora-` tion of thevalve relay VR at low speeds will be pointedy out ymore fully hereinafter.

Smmn-arjI/ of operation-4F or the sake of simplicity and convenience, the operations of; the various devices andcircuits constituting the system of this inventionhavebeen discussed more or lessseparately and independently.k Afull appreciation of the advantageous features and the whole scheme ofoperation is best obtained kby briefly summarizing the actions and operations in connection with automatic train movement in automatic block signal territory; and for this purpose there is shown in Fig. 2 a typical layoutV of Ainductors and curves'to facilitate explanation of the train movement. Y

Referring to the curves of Fig. 2, the curve 130 is afspeed-,distance curve representing the speeds at the various points in the block E atwhich an application of the brakesv must be initiatedin order to bringy the train to afstop at the end Tof this block. Thscurve iso Cil

130 is not intended to be exact, andbf 'course varies with the character of train braking equipment. l

Generally speaking, this curve 130 is a dead-line7V or limiting "curve of speeds which; under the particular conditions assumed, can never be exceeded by a train without therev being immediately .initiated an effective brake application, assumed to be a full service application. The maximum speed at which the train may pass thesignal at the end oi the block E is assumed to be twenty miles per hour. The Ilast pair of inducto'rs TF2 in the block E, traliic being from left to right' as indicated by the arrow, is spaced so as to Vprescribe a speed limit of twenty or twenty-two miles per hour. The location of this last pair of inductors TFJ is arbitrarily selected with due regard to the varying factors to aliordthe desired facility of train movement consistent with safety. The point where the line 131, projected upward from the second inductor of the pair Tl?2 cuts curve 130, gives the proper speed limit for the next pair of inductors TF1 in the rear, the probability of a train acceleratine between pairs of inductor's 'being disregarded for the sake of simplicity. The location of the intermediate pair of inductors TF1 is arbitrarily determined, but itss'pacing is such as to provide the speed limit as just stated. Similarly, the point where the line 132, projected vertically from a second inductor of the pair TF1, cuts the curve 130, determines the speed limit `for the first pair of inductors TF, which Amay be located arbitrarily as shown. i j

It should be understood that this particular arrangement of pairsofinductors andthis particular scheme for determining the spacing Yof these `inductors and their location is susceptible of considerable variation, and the present discussion is designed principally to facilitate explanation of the present invention without explaining in detail the characteristics ofthe time-distance interval system (ii-'speed control,'this system of speed control byk itself forming no partof the present invention. v v

'Assuming an arrangementand location of pairs of inductors, as just described,vthere`are thenthree different speedlimits indicated by the arrows v138, 134 and 135 which the train 4can not 'exceed at these particular 'points without "an automatic operation of the car equipment constructed'inaccordance with the time-distance interval systemso speed control. So ,long as the speed'of the `train is always .belowfthes'espeed limits, the valve relay VRo -Fig.A lfis maintained energized, and thereis rio-automatic brake application, norv need forthe engi-neer to make a manual brake application. In orderto keep below these speed limits, however` the train must ruirsomething'as indicated by the performance'curve 136, and it will be noted that this is at much lower V'speeds than is actually demanded by safety, the several safe speeds being represented by the curve '130.

Moreover, in order to bring the speed of his train below the speed prescribed by the lirst pair of induct'ors TF and indicated by the arrow 183, it is necessary for the engineer, particularly on down grades, to start his brake lapplication at some distance back of the first pair of inductors T F, with there'sult that, if this brake application is not made until the signal at the entrance to the block E is actually passed, the brakes will be automatically applied at the frstpair oi' inductors TF. A

Assume now that the block E is a vcaution block, all inductors being active, and assume that the-engineer is alert. The automatic operation (ivhich 'of course varies under dill'erent conditions), will be something as follows: with the engineer observing signal Z at the entrance to the'block E at caution and realizing that this train is running at high speed which is assumed to befthe case, rather than at speeds below the inducto'r speeds), moves his brake valve to the service position before aassing the tirst pair of inductors TF, at least, before deenergization of the valve relay VR. The penalty relay F is energized and maintained energized. It the engineer has made a predcteri'nined reduction in equalizingreservoir pressure, guided by thc signal 1..'3,"he-may lap his valve and avoid over-reduction. l i I lllien the train passes the first pair of inductors TF, the speed being excessive, the

Vvalverelay vVR-'f'is deen'ergized and the application valve is operated. As soon as the desired reduction has been made in cqualizing reservoir pressure by lthe'nianual action'oi the enginee \'cnti1ig'oif-t.l1e brake pipe by the application valve A is arrested. The application Valve however, always operates at cach pair of inductors, it the speed vis e2;- cessive, irrespective oi ,what action may have been taken by the engineer. The train new slows down` duc lo the brake application which may be said to be partly'manual and partly automatic, or afnninual application accompanied or followed up by an automatic application. 'l'he engineer can not release theln'akes because the slide valve 35 of the application valve A cuts olif main reservoir pressure. `The train continues with the brakes applied and in time wouldA stop before reachingthe end ot the block.

Imagine now that the train` with the application valve operating, and the penalty relay energized, passes the second pair o't inductors TF1 and suppose that danger conditions in the block ahead still existand the. second inductor oi this pair is still active. The impulse from the irst induct'or, thetime' element device TE having in the meantime returned to the normal position, automatically rcenergizes the valve relay V R. This, however, does noticause release of the brakes. ln the first place, 4the electro-pneumatic valve EFV will not be energized unless the engineers valve is in the release position; and in the second-place, even though energized, there would not be time to restore the application valve A and accomplish anything in recharging the brake pipebefore passing the second inductor of the pair, a matter of a second or two.

f the speed of the train is still above the inductor speed, as indicated by the curve 137, the valve relay VR is immediately deenergized and the braking conditi-ons continue. Tf, .however, it should happen that the train, being especially well braked orin exceeding the inductor speed 183 by very little, should pass thesecon d pair of inductors below the speed limit 184 prescribed thereby, the time element device TE will have. returned to the normal position before the relay RR drops for the second time; and the valve relay VR remains energized, permitting the engineer to energize the eleotro-pneumatic valve RFV by moving the brake valve to the release position, and resulting in thei'elease and restoration of the applicationvalve A and the suppression valve SV.

Suppose, however, that by the time Ythe train in question reaches the second pair of inductors, the block in advance has become unoccupied. Then, the winding on the sec-- ond inductor of the pair TF1 is on close-d circuit and no impulse is communicated thereby. The valve relay VR is restored by the irst inductor as before, and inasmuch as no second impulse is received,-| this relay VR remains energized, permittingI release of the brakes, irrespective of what the speed may be. the block ahead clear up, the fo-llowing train is automatically released at the first pair of inductors it thereafter passes and is permitted to acceleate immediately, providing a safe and ei'iicient form of intermediate rcleasein a faution block ordinarily not possible witha systei'n of train control employing intermittently acting impulse communicating' devices.' c v c If the block is still a caution block at the time the train passes the second pair of inductors TF1, the brakes must be kept on, as

previously explained. yAn automatic release and restoration of the valve relay VR would be possible at the third pair of inductors TF2 in case that the conditions have in the meantime cleared iup, or the speed has been reduced below the minimum speed. It Vmay happen, however, that a train would pass the last pair of inductors TF2 in the block above the speed limit 135 prescribed by these inductors; and in this event, there would be noy automatic release, the brakes would have to be kept on, and the train would be brought ln other words, if traffic conditions in to a stop. Also, the brakinr conditions, the inductor speed limits and other varying factors may be suchthat a train maybe stopped after passing the second pair of inductors and before reaching the third pair, if a full service application of the brakes is-maintained, In order to avoid any of these contingencies which would compel a train to stop, rather than permitting it tok proceed, the speed contacts 74 are providedso that whenever the speed of the train has been reduced below a predetermined minimumvalue relay VR is reset, providedof course the engineer hasbeen vigilant.

As already fully explained, the engineer must watch out for the indication of the block. signals and recognize the excessive speed and act before the automatic apparatus acts to deenergize the valve relay VR, otherwise the engineer is penalized by beingrequired to stop and operate the reset switch RS. In other words, the engineer can not disregard theblock signals or pay no attention to his speed and wait -until the automatic train control apparatus has operated, and thenact. This, it is believed, is an essential and important characteristic of any arrangement for enforcing Vigilance on the part of the engineer. The engineer should derive all information as to how and when to slow down his train'from his own observation of the signal indications and from his own realization of excessive speed;` and it should not be possible for him to wait until there is a signal, sound, or until he feels the brakes being applied, before he is required to take the appropriate action toavoid the penalty. n

As previously explained, thek audible signal or bell 123 isprovided to assist the engineer and advise him when he may lap his lengineers valve. Since the brakes once applied mustbe kept on until the electro-pneumatic valve EFVhas been reset, it is desirable for the engineer to know when this has happened and it is proper forhim to release the brakes. For this purpose therermay be added, if desired, a suitable visual or audible signalunder ythe control ofthe valve relay VR, so that the engineer mayknow as soon as this valve relay VR has been'reenergized, and may then move his regular brake valve to the release position and reenergize the elec-V tro-pneumatic valve EFV. The addition or adaptation ofrsuchva signal to the specic embodiment shown, being amatter of choice or preference and being obvious has not been illustrated.

ln addition to enforcing restricted speed limits on account of the presence vof other trains ahead, lit `is often desirable to require reduced speeds, irrespective o ftraihc condition, at certain places along the railroad where the so-called fixed hazards exist, For example, sharp curves, down grades, yard limits, crossings, and lother permanent hazi ardsfaleng 'tli'e railroad make it desirable to enforce a'iedu-ce@` speed limit at` these parf places. Inaccordance,with the type si ed control hereinillustrated, such restrictions upon the maximum speed of the train'at vari-ous points underciear traliic conditions are accomplished by a pair otperin'an'ently actiif'elinduc'tors located at the desired point landspaced the appropriate distance apart. Such a pair of inductors TM are illustrated in Fig. :2 near the ond oit the block-D. Both of the inductors otthis pair are Without coils orivindings 7,- and both always act upon the car apparatus, irrespective 'of the presence or absence of other trains, to cause an automatic brake lapplication if the speed. ot'the train at this particu-lar point exceeds the predetermined limit desired and prescribed by the 'spacing'- ot the induc'to'rs. According to Athe present invention, the engineer must recognize the existence of these limited speedv Zonesor control points, the same as fora caution block; audit the speed of the train is above the prescribed limit, the engineer -must initiate a brake application in the same Way already described, in order to avoid the penalty. The provision of this suppressed penalty fea-ture, characteristic of this invention, serves to facilitate train movement at these pointsoli restrict-ed speed, as Well as fat the control points in acaution block. To illustrate, referring to Fig, 24, assuming` that, on account of thef permanent hazard near the sig-'nal Z, it is desired to have a restricted speed at thesignal, say 40 miles per hour. The rpe-rmane'ntly active pair of linductors TM must, lthen, he located a. distance back ofthe sign-all Z sutiicient to bring the train from its possible norma-l running maximum speed, say Oiniles per Lhour, -to i() miles per hour. Tn other `words, the speed limit. prescribed 'by the indnctors TM must, inthe interests oi' safety be 4t() miles per hour or even lcss it acceleration is'to be taken into consideration, oven thoughthis 4() miles per hour speed is not necessary until the si is rez-relied. llyi'thout the ezipedient oi supssed penalty of this invention, and with the system of .thoftype in which a penalty is imposed Whenever an automatic braise application occurs, itl can be seenthat the en gineer is required 'to reducerspee-d much sooner than really necessary, being e() miles per :hour at the inductors TM, although not necessary to be atthis speed until reaching the signal; lith the present ii'iven'tion, however, the en- `gineer may proceed at the regular normal running speed up to the inductors TisLand then it'vigilant and `rcalizin,Y the need tor i reduced speed, the. engineer may initiate a brake application, avoiding` the penalty by so doing, and eventually bringing his train to the desired intermediate speed by the'tiino the point 'for such restricted speed is reached.

lin a particular arrangement selected as a typical illustration and shoivn in Fig. 2, it assumed that the first inductor of the pair Tl) will servo to reset the valve relay VR, after deenergization thereotI at the pair of inductors TM, making, it possible for the engineer to release the brakes after having' brought the speed' ot' the train down to the desired exten-t. This particular arrangement, however, is merely illustrative, and it should be understood that,v it necessary, a special single inductor may be locate-d at the appropriate point in advance ot a pair ot permanently active indnctors to reset vthe apparatus after the desired speed limit has been e forced. Incidentally, it should also be understood that the pair of permanently active inductors TM must have their location chosen so as not to produce a false or iinproner restoration of the car apparatus while the ltrain is in a caution block and a brake application must be maintained for the salte ot' safety. It it should happen to be necessary to locate the pair of inductors, such af; TM, for cntorci a restricted speed limit for permanent hazards under clear traliic conditions at such a pointas would interfere with the proper control of the train under caution trali'ic conditions, this pair otl inductors may be provided With windu-ras automatically placed on close-d circuit under caution conditions and on open circ-uit under clear conditions, it being obvious that there is no need for the maximum speed limit provided by such pair under caution traliic conditions.

lVith respect to the particular advantages and value of this invention in its practical application to the automatic train control problem, the first feature of significance relates to the additional facility ot train move.- ment ailforded With the same degree oi safety. As outlined hereinbefore, it is assumed to be an established'principle that any system ot train control should be such that thc cngineer can not relax his vigilance or use any less care in Watchingtor the signal indications and handling his train than it the train were not equipped with train control apparatus. It has already .been proposed to maintain or assure such vigilance on the part ol the engineer by imposingl a penality whenever an automatic application of the brakes occurs on account ot' excessive speed. ln other words, Whenever the train exceeds the dead-line curve ot limiting spoed, andan automatic operation occurs, the penalty is inflicted. According to this proposed scheme, it will be evident that the engineer is rcquired to govern the speed ot his train in conformity with such dead-line, curves; but when it comes Ato establishing such a dead-line. curve for all blocks, all grades, nahe-up .ottraiin .and other varying faetors, it is iound that it Vis frequently necessary for the engineer, in order .to avoid the penalty, .to govern thel train in a peculiar system, rather than compelling 'the'trainjiii eral statein'eiideven iii asystemproi/.idi

all conditions;and Athis difficulty is foundto a more or less degree'in all known types oi speed control systems, Whetheij intermittently or continuously acting', whether oi the `point-to-point speed limit type, such as the time-distance interval system herein 'disclosed, or a continuing speed limit type employing a speed responsive devieeivith either a gradual or abrupt change in'speed limits.

lVith reference'to the essentials'ot' safety, however, it can be readily seen that it is proper for the train to exeeed'tlie speedflimits arbitrarily established, provided the train is being- .sloived down with abi-alie application as eileetiveand corresponding to that upon which the arbitrary speed limits arebased. Obviously, it is immaterial Whether this brake application be manual vor automatic,-so"lone` as itis actually eiiectiveand ivillgstoptlie train iii time. Bearing these points" in mind, it can be appreciated that the system of this. in vention, ,While it lmaintains the samef yigilance andalert'ness" ot' the engineer, permits the train to run safely at higherV 'speeds ythan those .arbitrarily prescribed by the automatic everyiiistanc'e to keep below such arbitrary speed limits. A comparison ofthe perforin ance curves 136 and in Fig. 2,; shows a typical instance'oit the saving fof vtime and the additional facility of train movement aifoi-ded by this invention, as compared ywith the system ivhcre a penalty is inflicted every time the limiting` speed/limits are exceeded,

ifi-Xmong` other tliiiigsthe additional facility in train movement is due .to kthe possible vd ecreased length of blocks.` To`illustrate,if ,f

the train is obliged to yfollow ac performance curve su'o'lias indicated at 136, the bialtesniii'st be applied atfsonie distance baclg` of the `lirst4 pairof iiiduetors TP; aiidpiii strict coiit'or'i'n-` ityivith the principles of bloclrjsignalsdit `vixould follow that the signal Z would,lilie-v Wise have to be placed further back at' the point Wlieielliis brake application has to i be started, i'zliereby"increasing Vthe lengthl oi' the kblock considerably niore than braking distance toithe maximum speed The morey restricted or inaccurate tliespeed limits provided by the system 'of autoniatictrain con-V, trol, the more Atliegainf` intacility by einployiiig'the 'principle oi. suppressed penaltyL characterizing vthis invention; and as a rgeii-- e ycuri/ect permissive or lii iting: speed, l 1ere ja" situationsV Where iii'tiineaiid'increase in traelijeapacity.

tlie e` is a material savingA yentioii is that itjfacilitatesand simplities'the ,handling of the train by the engineer,v Instead of beingl required to estimate' quite accurately. the actual running speed and the varying speed limits permissible at different points, the engineer merely has to ascertain outlthe train control equipment, governing his actionsin accordance with the signal in- -dic tions and locations. Such va procedure is considerably simpler and easier than trying to run to certainarbitrarily set speed limits. To certain extent, this inventionv gives additional sai'ety. lt inust'be recognized that Yaiitom'atie devices sometimes get out ott order. if 'the'engineer gets in the habit of depending,` upon thev automatic equipment and Waiting for laction tliereby,` a dangerous condition may created. With the arrangement of this invention, however, the engineer has lno VWay of knowing Whenthe apparatus is not functioning properly, and being 'penalized for failure maire a timely vbrake app'l'ieaf tion,` tlie engineer as a rule willvalways apply the brakes and 'stop'the train safely, even thou'ghfsoine part otvtlie automatic control apparatus Vmay kbe out oi" order.

ltfgslioul'df' als'o be understood that the' penalty imposed does not interfere or prevent "the handling of the train in the regular way;v Injtliecase o'long freight trains, for ei;- amplefyvhere it maybe desirable' to split thereduetions to adjust the slack, these split applications maybe made Without diiiiculty -before/l'efxceeding tlie'criticalspeed limits, it being observed thatthe suppression valvev SV is responsive to a certain reduction in equalizing' reservoirpressure, ivlietlieitliat reductvio or more stages. lnasmueli'astlie critical speed 4limitsare based upon a fullservice applicationimmediately applied, it is evi# d'entjtlia`tl `the splitting of Vapplications rshould take plaeebefore these speed limi' are eirceeded, sincetliis is the' only Way in. ivliiclrthe' tra-iii "bestopped safely, di garding 'the inaccuracies `oit the 'i'ieiinissible speed' li'nriits.` i y While the inveiitioiilias been slinnf'n appliedviii to a system einplayingl a piui'ality of speed /lii'nitcontrol points in a block,

the rsaine o rgaiiizatioii'may be usedivith any number of speedliinits. For example, there may only one speed limit at the entrance to" a block, or the pair of induetors may be .so-,closely spacedas anY automatic stop independent oi speed. ln fact, asiniple automatic stop arrangement be used for withy or Without "overlap, may certain portions of the ,i'ai'li'oa tionlie made continuously in one stage or in Y Y 7.., anda more complete orreined system of 'speed vcontrol roughly thattlie speed excessive and apply the' bra-lies. To aI large extent the engineer may run his train the same ashe would With ieu isa y the eeluiveieiie si* ineiit of Fig. 1, hereinbetore explained, the reducti-on occurring upon an automatic application is limited by a manualaction of the engineer in reducing equalizing reservoir pressure. It is considere-d that this arrangement is not objectionable, excessive reduction occurring only in the event of wilful neglect by the engineer, or if the engineer is incapacitated. The amount of brake pipe reduction occurring upon automatic application may, it desired, be automatically limited; and the modiiied construction of the application valveA shown in Fig. 3 is designed, among other things, to perform this function.

' Thisapplication valve of Fig. 3 is very similar in its construction and operation to that shown in Fig. 1 and already described, so that` only the differences need be pointed out. The equalizing piston discharge valve 42 exhausts through pipe 48 and cavity 47 are direct to atmosphere, rather than under theV control of the slide valve 52. The reservoir ER is connected by pipe 43 and cavity 44 to a pipe 45, the same as in Fig. 1; but the pipe 45 in Fig, 3, instead of connecting permanently and directly with the brake pipe, is

connected tothe brake pipe through an addiV tional valve 140 on the electro-pneumatic valve 58, this valve 140 being open While the engineers valve is in the running position and being closed in the otlier'positions of the engineers valve. VIn short, there isAp-roducedV when the application valve has operated Thus, the normal brake pipe pressure trapped inthe reservoir ER is expanded into the reduction reservoir RD, normally at atmospheric pressure', through a restricted opening corresponding approximately in size to the preliminary exhaust port in the regular engineers brake valve. Consequently,pressure in the ieservoir ER drops at av predetermined rate and to'a predetermined value, namely, pressure at which pressure equalizes in the reservoirs ER and RD. It Will'bev obvious .that the resultant or equalization pressure,

ivhich determines the amount of brake pipe reduction, may be anything desired by pro-l portioning. the volumes of reservoirs ER and This lmodified construction shown in Fig.

l 3 operates in the saine' way as previously? explained, with the exceptienth'at ythe applicadevices and circuits disclosed. Vhave it understood, therefore, that the invention 4is not limited to the particular Ways and `SV, and as a result, brake pipe pressure is limited upon automatic application irrespec- A tive of any action'bytlie engineer.

A restricted orifice 142 is employed so as to reduce the pressure in the reservoir ER at approximately the same rate as the pressure drops in the regular equalizing reservoir, making it possible to vent the brake pipe in two places without exceeding the limited rate at which the brake pipe. may be vented Without throwing the triple valves into quick action and producing an emergency applica- Vtion which may be particularly objectionable on long freight trains. j

I'Vhile a specific type of' speed control system has been disclosed in conjunction with this invention, and While the specific and particular form of means, partly pneumatic, and partly electrical, been disclosed for carrying out thejfunctions of this invention, it will be evident that this particu-lar disclosure is susceptible of considerable modilication and adaptation without sacrificing the advantageous characteristics and features of the invention or departing from the spirit of the invention. Y

As a general proposition, this, particular invention has referenceito the suppressionof penalty if the engineervactually controls the train safely by a brake application, so as to permit a predetermined speed limit being exceeded Without penalty. In its broadest aspect, the invention is not limited to any particular means for communicating impulses from the traclway to the vehicle, such means being either intermittently acting or continuously acting; nor to any particular type lof speed control system; nor to any of the specific organizations and arrangements ot I desire to meansA herein described and shown, but is susceptible of broad application so far as comes `Within the scope ot the appended claims.

' lVhat I claim is j 1. In an automatic train control system for railroads, the combination with the air-brake equipment ot a vehicle, of an automatic brake setting device acting on said equipment to produce a brake application of a predetermined efl'ect, automatic apparatus on the vehicle controlled from the trackway in accordance with traiiic, conditions for causing operation of said device it the vehicle exceeds certain 'speed limits during its progress While'dangeroustraffic conditions exist ahead,

said apparatus including control means Vwhich once'operatedreniains in that condition until restored, manually 'o'perableineans accessible only from thcground forrcstining' said control means, and other mean for permitting restoration of said control means -andoliectire only if .the engineer manually initiates abrake application priorto the `operation:et

'said brake setting'device and thereafter maintains an el'ectivefbrake application. y 2. In an automatic train: control system 'tor railway vehicles equipped with an air-brake system, automatic apparatus on a Vehicle for causing a brake application under predetermined conditions of trailic and speed, .aid apparatus when :once operated continuinpl such brake application until restored, and means to restore saidr apparatus and .permit the .release ot the brakes, said means being eli'ective ronly it the engineer initiates a manual brak3 application prior .to thel automatic operation of said apparatus.

In a train control vsystem@` automatic brake control apparatus on a vehicleV operatedv automatically dependent on traffic conditions f and the running speed of the yehicle,-said apparatus When once (nie-rated tending to bring the vehicle to a: stop before the brakes can'be.- released, and means etlectiye .only if vthe engineer manually appliesthevbrakes prior to the kautoinatic operation of said 'apparatusOr permitting restoration thereof as soon as the speed of the"v Vehicle has been reduced to a safe speed.-y

4l. `In-a train controlV system, brake control apparatus, on a vehicle automatically operated dependent upon trailic conditions and the running speed of the'velnclc to. make apiull` service application, apparatus causing)y such vbrake application each time the prescribed speed limits are exceeded-irrespective ot any action 'by the engineer, and-:means permitting' restoration oi5 said apparatus and rclease oi thebralges after the-,specdfhasbeen reduced below the prescril)edilimits,provided that prior tothe automatic operation saidA apparatus the engineer manually initiateda brake application. i y 5. Ina train control system,thccombination with automatic brake control vapparatus' on ayehicle,y ot means ope 1ablefonly it apre-A determined brale application is inlotlect, said means permitting :restoration of said apparatus after the speed olY theyehicle has'been reduced to a safe limit Vbut permitting ysaid apparatus to operatev each Ytime the ispeedxis excessive. I u y. y

"6; In ,atrain control` system of the general type described` characterized by ,thef auto-- matic application fof the brakesWheneverthe speed offthe veliiclrefequipped Withsaidsystemk is excessive, penalty meanslrecniiringy special action on the partei' the engineer before the brakes can be released:andl the train proceed. after each'l automatic-brake applica.- tion," andwmeans forrendering said penalty means ineectiife and. permitting thetrain to proceed without such special action, 'saidlast.v

vpendent*.upon the running speed-of said rehicle,` and further characterized by theimposition 'of a penalty upon the engineer for failure to initiate ama-unal brake applicationfprior Vto such automatic brake application, the combination ofautomatic brake setting apparatus yoperable each time the speed is excessive and irrespective-of any action'by the engineer of means forfsuppressing said penalty only provided-that the engineer in- Yitiates said'manual brake application prior to the automaticopera'tion of saidapparatus 8. In a system of automatic train control in which the Vigilance of theiengineer: is maintained by imposing a penalty for failure to take appropriate action` upon the occur- .renceo each automatic brake application,y

the combination with an automatic brake setting' device actingupon the'air-.brake equipment of vehicle to produce: asubstantially full. service brake application; of means -for suppressing` said penalty-Without. preventingoperation of said brake setting device, said means being'fetfective only if the engineers brake valve isplaced in the yservice positionV prior, to the automatic operation of saidde- 'Vice and kept thereuntil a substantially full service vbrake application has been manually effected. y Y Y i y ,Y

- 9. .A trainl control system for railroads comprising, automatic apparatus v`onthe Vehicle dependent upon trailicconditionsand the running speed of the vehicle vfor produc'- ine' an automatic brakea i alication of a ,re-.f

determined effect, said apparatosfoperating eachftime traffic -conditionsland the running; spoed require, irrespectiye of anyvaction on the part of the engineenand. automatic means for imposing the penalty onthe engineer each time said apparatus operates unless prior to said automatic operation tho"engineer places his brake valve'in the servici-)position and `maintains it there until a predetermined rcduction has been made in the normal run ning; pressure vin" the equalizing reservoir of the air-brake system..v

10. A trainv control system `for 'railroads comprising, automatic apparatus onr thevehicle vdependent upon traliic conditions and ythe running speed'oi the vehicle .forlproduc-l .ing-'an automaticlbrakeapplication ofa kpre-g determined effect, said' apparatus operatingI each/time traiic Acmditions and the running specd'require, irrespectireof yany actiony on, Y

theipart of the engineer, penalty `suppress:` ingmeans if ellective permitting restoration of saidapparatus and release ofthe rbrakes* as soon as the speed of the vehicle has been Ybrought substantially to a stop, and means for rendering said penalty suppressing means effective only if prior to the automatic operation of said apparatus, the engineers brake valve is in the service' position and remains in that position or if there actually exists a predetermined reduction in the normal running pressure in the equalizing reservoir of the air-brake system.

11. A train cont-rol system for railroads comprising, automatic apparatus on the vehicle dependent upon traflic conditions and the running speed of the vehicle for producing an automatic brake application of a predetermined effect, said apparatus operating each time tratlic` conditions and the running Y -speed require, irrespective of any action on the ground for restoring said apparatus, a.

aenalt i su vressinfr means said a aratus :n .i beingy rest-orable to permit release of the `brakes independently of said restoring device only if said penalty suppressing means is effective and automaticl means for rendering said penalty suppressing means effective provided the engineer prior to the automatic operation of said apparatus places his brake valve in the service position and keeps it there until a predetermined reduction has been made in thenormalrunning pressure in the equalizing reservoir.

12. In'an automatic train control system, car-carried equipment comprising, an automatic brak-e. setting appliance acting upon the air-brake` system of the vehicle to produce av predetermined brake application, apparatus controlled from the trackivay in accordance with traiiic conditions for governing the operation of said appliance, a penalty suppressing means, and means for rendering said penalty suppressing means effective ivithout preventing operation of said appliv ance provided the engineer manually applies the brakes prior to the operation oi said appliance. f

13. In a train control system of the character described in Vvwhich a penalty for lthe engineer maybe suppressed by appropriate act-ion on his part Without preventing the operation of the automat-ic brake setting means, the combination with means for suppressing said penalty, of means for rendering said penalty suppressing means eii'ective only vif the engineeris brake `valve is in the service position, and other means for renderl ingsaid. penalty suppressing means effective provided there actually exists a predeter- Vininedreductien in the normal running pressuie in the equalizing reservoir of the airbrake system.

14. In a train control system of the character described in which a penalty for the engineer may be suppressed by appropriate action on his part Without preventing the operation of the automatic brake setting v'means, a penalty suppressing device, a circuit or rendering said devices etl'ective having two branches in multiple, contacts in one branch roperatively connected to the encircuit controller in the other branch automatically closed only if and so long as there exists a predetermined reduction in the normal'running pressure in the equalizing reservoir of the air-brake system.

15. In a train control systemof the character described, the combination with an airbrake system, of a normally open circuit having two branches in multiple, means for closing one oi' said branches if the regular en- Oineers brake valve of the air-brake s stem. D

is in the service position and for opening lsaid branch if said brake valve is in any other position, and pneuinatically operated circuit controlling means automatically closed provided there exists a. predetermined reduction in the pressure in the equalizing reservoir of the air-brake system. v

16. ln a train control system of the type described, a penalty stick relay, the stick circuit for said relay having two branches in multiple, contacts in one branch connected to the regular engineers brake valve and closed only if said valve is in the service position, circuit controlling means for closing the other branch providing the pressure in the regular equalizing reservoir of the airbrake system has been reduced to a predetermined extent, and automatic brake control apparatus having its restoration but not its initial operation dependent upon said penalty relay.

17. In atrain control system for vehicles equipped with an air-brake system of the usual type, automatic lbrake-setting apparatus including an electro-pneumatic valve, a stick relay on the vehicle controlling said electro-pneumatic valve, and automatically deenergized at certain points along the trackway Whenever the speed of the vehicle exceeds predetermined speed limits While passing said points, a normally open pick-up circuit for said stick relay, and means permitting closure of said circuit only if prior to the deenergization of said relay the' regular engineers brake valve of the air-brake system is in the service position.

18. Car equipment vfortrain control systems comprising, in combination with anraifbrake system ofthe usual type includingan equalizing reservoir, circuitcontrolling means automatically operatedby air pressure,'and means for supplying pressure to said circuit controlling means only if there eXists a predetermined difference between the equalizing res ervoir pressure and the normal running brake p-ipe pressure.

19. ln an automatic train` control system,

car equipment for railway vehicles equipped with an airbrake system of the usual type comprising, an electrically controlled and pneumatically operated brake application valve acting upon said system to produce an automaticy application of the brakes, a stick relay controlling said application valve, automatic means controllable "from the trackway phi for deenergizing and maintaining deenergized said stick relay'at predetermined control points along the track ir the speed of the vehicle at the particular control point eX- ceeds a: predetermined speed limit, means pern initt-ing reenergization oi said stick relay ai'-A ter thespeed of the vehicle has been reduced to a predetermined minimuml only provided that prior to the deenergization of said relay the engineerplaces his brake valve in the service' position and keeps it there until an effectivebrake application has loeenvprof,`

duced.` l l 2O.y In an automatic train control system for governing the movement of railivayve- `hicles equipped with air brakes, a brake setting device on the vehicle opera le toproduce an automatic brake application, astick relay on the vehicle controlling the operation of said device, trackvvayl vmeans, at predeter` mined control points defining space intervals,

a time element devicer on the vehicle cont-rol-` ling said stick relay, said trackway means acting automatically in cooperation with said time element ydevice to cause deenergiZa-tion oi said relay Whenever the vehicle takes less than a predetermined time in traveling over any one ofsaid space intervals, a penalty vre-.V`

` lay on the vehicle, said apparatus being autof matically restored at any one of said control points if the vehicle takes more than said time in traveling the space interval at that point p provided said penalty relay is energized, and means forl energizingsaidpenalty relay, saidv y, means being effective only if a manual appli* i cation of the brakes is initiated or kcompleted prior to the deenergization of said stick relay. 21. An automatic train control system for Ygoverning speed of railway vehicles through theblocks of an automatic block signal system i comprising, car .equipment including appa-l `ratus for act-inVU automaticall Vii on the` airbrakeI equipment of' the vehicle and causing a brake application 4ofpredetermined etlect Whenever? the vehicle exceeds successively 'lower speed limits during its progress through a block Withl a nest block-in advance occupied, Vsaid apparatus when once voperated due to the exceeding of said speed limits continuing in operation and maintaining the brakesap-y plied until restored', manually operable means Vaccessible onlylromthe ground for restoringsaid apparatus, the operation of said restoring means constituting a penalty, a penalty suppression device on the vehicle, means partly on the vehicle and lpart-lyon the track for ycausing restoration of said apparatus at intermediate points in the block if the speed ot the vehicle is then below the limit for that particular point and provided said penalty suppression device is then eitecti've. and means for lreiideriiig said penalty suppression device effective only it operated prior to the auto# matic operation of said apparatus, said last mentioned means requiring the engineer to put his `brake valve inthe service position and keep it there until a brake application of predeterminedl effect has been produced.

22. In a. speed control system for railroads divided into track circuited blocks, brake controlapparatus on a vehicle automatically set into operation near -the. entrancev to a block if thejn'eirt block in advance is occupied, said apparatus continuing in operation until re'-v stoifed, and `means for restoring said Vapparatus alter the speed of-thevehicle has been reduced to predetermined minimum ,providedV that the engineer anticipatesthe automatic operation* of said apparatus With an effective manual brake application.

23. ifiutomatictrain control equipment for railway vehicles having an air-brakefsystein .ot the vusual typecomprising, an automatic brake control appliance adapted to act upon said air-brake system and producea brake aping operable only by'said meansl and onlyV pre-vided one of said :means is effective prior to the automatic operation of said brake coneV trol appliance. i u

24. .ln a train control system, apparatus on trackivay and on a moving vehicle cooperating under dangerous traiiic conditions to produce an. automatic brakeapplicatien .vvlien.

ever thevehicle takes less thana predetermined time in traveling a predetermined distance, said apparatus When once operated continuing in that condition and maintaining the brakes applied .until restored, manually operable means orrestoring said apparatus only after theV vehicle has been brought substantially to a stop, .and means permitting restoration of saidfapparatus at predetermined speeds Without requiring the stopping thereof, said last mentioned means loeii'g'erlice-tion isin effect, said penalty relay be-`

Images