US1771715A - Railway-traffic-controlling apparatus - Google Patents

Description

'July 29, 1930. s, LQOMIS ET AL 1,771,715

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 15, 1928 4 Sheets-Sheet l July 29, 1930. H, s, Looms ET AL 1,771,715

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 15, 1928 4 Sheets-Sheet 2 R N m A i O INVENTOR S mam 1. f

July 29 1930. I s, LQQMISEF AL 7 1,771,715

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 15', 1928 4 Sheets-Sheet a Source of Fluid Pressure Brake Pzjoe INVENTORSI y 1930. H. s. LOOMIS ET AL 1,771,715

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May- 15, 1928 4 Sheets-Sheet 4 v m mg w Em w Patented July 29, 1930 V UN1TED5TATE5 P ENTLQFFICE HAROLD s.- noolvrrs, on ,wiLxmsncne, nn HOWARD A. THomrsoN, on EDGEWOOD; BOROUGH, PENNSYLVANIA; ASSIGNORS TO-THE UNION swxrcnk; SIGNAL M:-

PANY, OF SWISSVALE} PENNSYLVANIA,

A- CORPORATION OF PENNSYLVANIA RAiCLWAY TBAFFZC-CQNTRQLLING Hu mus Application fil afivm 15,

Our invention relates to railway trafiiccontrolling epp'eretiis, and particularly to epparatus of the type comprislng train carried governing imeans' controlled by devices cet ed at'interv-als along the trackway;

One featnreof-oi'ir intention isthe pro vision in apparatus '01: thetype described of train carried governing means which is eftectiveattiines tocause a service application; of the brakes Which can be released by the engineman only after the expiration of a time intervalwhich is of such length as toin-I su'rcthat the train speed has been reduced to a comparativelylow value. 1

Another feature of our'invention ,is the provision of means for preventing anhuto V nlatic application of the brakes, even; under unsafe traffic conditionsyifthe speedof the train is below the value froniivhich the serv ice applicationcen bring thetrein to a full stop short of the hazard which render ing trafiic conditionsiinsai'e. i

Other features andhdvantltges of our partly dia'grammatio and partly in section,

showing one form of train carried governing means suitable'tor cooperation with the track- Waynpparatusillustratednn Figs. 1 and 2 and alsosinbodying our invention. F

. is ediagra'n'imatic View showingin modified i Fig. 11, andelsoeinhodying onr invent-ion.

iorin a portionef the apparatus shown in Similar reiierence chzira'ctersrcfer to similar parts in each or the severalVieWs.

Referring first to Figs- 1 and 2, the reference jcheracters l and 1 designate the" rails of a e etch of railway track over; which trafj ficnorn elly moves ingthei d 'ection;indicat-; ed: by ithe errow. "ilhese-raxds are I divided, 1' inc-ens insulatedjointsfi to formpe plu f ialitj of successive track sections AB,

vention will appear fas the description; pro

7 tion islprovided Witll'a trackjciricnit compris r lngithe secondaryofa track transformer 4, e i 'ei f tr k m y e P ima y of.

1928. see-e1. .Nol z'zspcs.

B,C C D; D 43, end IE- F. Each track section is provided with aIsourceoftreckY circuit current here shown as a transformer designated by the referenceclmracter with an exponentcorresponding to the location" and hztvingits secondary connected j a x 5 the rails: tidjecent the exit thesection. The primary of eachtrack'transformer is constantlysupnlied with alternating current from a suitebl e'source of energy such as it linetransfmmer designated by the reference character 7 with an exponent; corresponding tofthe location and siipplied with energy' from a r alternator M overline Wires3. In

' order to simplify the drewingwe have ornitj 5 ted the wireswhich connectthefterminals of I the secondary of the several, linej transform ers Wrththeapparetus to which these seepedi pp y ner y; et r i iiml b ch]? 1 line transformer'seconderya re design ated the reference characters- X 'andjYfW-itli ex l ponents corresponding to the locatiomend similar reference characters are applied ft'o j the terminals ofth'e various circuits; v Each track section u x v is also provided a track relay designated by the referencecher actor B with g n-exponent corresponding fo the location and connected across the .rziils adpicent theentran'ce endofthelsection. one

rail 1 of each section is providcd with an additional irr'isulated.joint,2? at ap'oin't in the rear of'the exit end of the section. :The primary of a transformer 5 is connected across L eachsuch joint 2 andthe secondary ofeach -such transformer 5 is c 0nnectec1 through a ignzttedbythe reference charz cter J with an appropriate distinguishing exponent. Iti v W1l1'be plain, therefore, that eachtrack sec:

a transformer 5, and the rails' of the sect-ion;

andthfe tissociated relay J is also energized. j

: W-Yhen enter s tliei sectiong the track imm tel b me i en r iz u the reley J for, that section remains "en'epq gized until the train passes insulated joint 2* whereupon relay J opens and remains open until the train has passed out of the section.

Each section is also provided with a polarized home. relay and a home repeater relay designated by the reference characters H and terininalsIX and Y of'transformer 7 A and; when the circuit just tracedlis; closed, relay.

. Hf i s ,.energiz ed infone direction, which I L from a trainsformer 19 the primaryof which. is constantly cqnnected. with terminals X3 and Y of line transformer? 3. Oiiecircuit. for relay Q? may. be tracedfroin the upper will calljthe normal directiodsothat its con! tacts are swung; to (the. left. \Nhen rel G? is. 'de-energized, however, the lower terminal of thesecondary'of transformer 12 is connectedwith wire- 15,, Overbacki. contact. l l of relay, GB. and. under .these conditions, therel-.

atiye q'larity of, the current supplied to. the windiiig 8] of relay H is reversedso. that the relay isenergized in its reverse direction to swingitscontactsto the right, When relay His energizedin eitherits, normal, or reverse direction, current is supplied, to relay G, over c ntactBL of relayH so that relay G is energized. Vltheiilrelay H? isde-energiaed, however, the circuit f91; r.e'1ay; G is nterrup he att'e lay. 15 def energized. The circuits fQreach, of, the; re-

maining'relaysH and G aresimilar to those; i l tdes r bed fer re ays. Ht ndG. andwill e idr teodfronithe awing .Wi hP-u? 1- ie je p anat en.

pel r d. d st n l y. de igna ed? by t referencejchara'cter Q with} a suitable exponent andcomp'risingtwo windingslO andjl'l,

one of which, v 11, is constantly supplied. with alternating current from terminals Xff and. Y4." 'Assoc'iatediwith' each distant relay Q, is a distantjrepeater relay designated by the. reference character P with an appropriate ex ponent 1 Referring particularly, ltoflrelay. .QA,

this relay isfa't times suppliedwith energy.

terminal of the secondaryoftransformer. 19 through wire 132,. frontcontact, 21 of relay Pl, wire 22,:front c0ntacti23j of relay Ga, wire 24, normal contact 25 ofrelay H wire 26, frontcontact' 27 of relay G4, wire 28,

winding 1Oof relayQ ancient-29 to the midpoint -3of'-' the secondary "of" transformer 19}? w en; the circuit j ust; tracedis closed,

Eac r ck sect n. is else prov ded wit 2- relay Q is energized in the normal direction to swing its contacts to the left. When relay P is de-energized, however, the lower terminal of the secondary of transformer 19 is connected with wire 22, over wire 30 and back contact 21 of relay P and under these conditions the polarity of the current supplied to relay Q is such that the relay is energized. in its reverse direction to swing its contacts to the right. Relay P is energized when relay Q is energized in either direction but is de-energized when relay Q is de-energized. The remaining relays Q and P are provided with circuits similar to those just described for Q and'P Associated with each section is a governingdevice designated by the reference character L with a suitable. exponent. and arrangedtocooperate with train carried governing means as will'be described. in detail hereinafter. Eachof the devices L is biased to an effective position (see L but maybe moved to an, ineffective position (see-L by means of. operating mechanism not shown in the drawing. Each device L also comprises a contact 51 which is arranged to be closed when the device occupies its ineffectiveposition. but to be open whenthe device occupies its effective position. One form of device operating in the mannerdescribed isdisclosed and claimedin Letters Patent of the United StatesNo.,1,59 1,988, issued July13, 1926,

to VVillianlG. MclVhirter, for railway traffic contnollingapparatus. 7

Each of thedevices L. is provided with a main.operatingv circuitand a number ofauxiliary circuits. Referring] particularly to device. L the main circuit for this device maybe tracedfrom. terminal X overv front contact 33 of relay R wire 34, front contact 35 of. relay G wirer36, normal contact 37 of. relayl-I-f, wire 38, front contact 39 of rela y P wire 40, normal contact 41 of relay 4, and WiresAQ, 43, 44, 45, 46,47, and 48, through the operating mechanismof device L4 to terminal Y When. this circuit is closed the device. L occupiesits ineffective position but;if the circuit is, for any reason interrupted, the device moves toits effective position. i

Associated with each section isa trackway signal which in the form shown is a light The middle arm m of 'each signal comprises three red units, two'yellow units, and one green unit, and the bottom arm on of each signal comprises two red units and one green unit; 1 Each signals is controlled in part by For example,

is open; Underthese conditions, the main circuit for device L is open so that this device OCCLlPlGSJtSGfiBClJIVG conditionr Since a front contact 59 of relay R is open, the cir cuit for light-out relay K is open and this relay is deenergized. Under these conditions,-current flows from terminal X over back contact 53 of relayK wire 54,1a red unit of the middle arm of signal" S wire 55, a ma unitof the bottom arm 5, wires 56 and 57, a red unit of thetop arm t-of signal S and wire 58 toterminal Y The indication presented by the signal under these conditions isthree-red lights in a vertical row.

The current "supplied to section EF- transformer l energizes relay J land relay R but the circuitfor relay H is open at front contact 16 ofrelay R so that relay H is tie-energized. Relays *RQ and P are also dc-energized. The main circuit for device L is'therefore open and this device occupies its efiectivexposition. Under the conditions just described, current flows from terminal X over front'contact 59 of relay R wire 60, winding of relay K wire 61,

back contact 63 of relay G wire 64,21 yellow unit of middle arm m of signal S w'ires65 and 66, aired unit of the bottom arm 5, wires 67 and 68*, a red unit of-thetop arm 15, and wire 69 to terminal Y The aspect-now displayed by signal S is a red light over a yellow light over a red light. i

Relays J and R associated with section DE are'both energized and since'relay G is de-energized, current is now supplied to relay H to energize this relay in-its reverse direction. Relay G is therefore energized but relays Q and P are open. The main operating circuit for devices L is open and: the device occupies its eife'ctive posltionp The aspect now displayed'by signal SP com prises a red light over a yellow light over a iial X, over front contact 59 of' relay R \vireGO, winding of relay KP, wire 61, front contact 63 of relayG wire 62, reverse contact *(0 ofrelay H, wire 71, a yellow unit ofv the middle arm m ofsignal ghfwire 72, a greenunit of the bottom arm 6, Wire 68, a

top arm t and wire to red unit of theterminal Y. A v 1 4 Referring now: to section C'D,jrelaysJ and R are both energized. Since relay. G is energizedfihe current supplied to relay H position.

"reen light, the circuit passing from termi-- energizes this relay initsinormal direction and relay G is energized but relays Q and.

P arebothde-energized. Under these conditlons the'circuit forv deviceL is open so that this device (occupies its effective position. The circuit for signal S underthese conditions may be traced from terminalX over-front contact,59 of relay Rfl wire 60,

Winding of relay KC, wire 61, front 3 contact 63 of rela G wire 62 normal contact 70' of relay H wire 73, back contact 74 of relay 1?, wire 75, a red unit of the middle arm m of sig11al"S ,w1res 76 and 77, a yellow unit of the top arm t,wires 78 and 79; a red unit of the bottom arm-3b, and wire 80 to terminal Y. The aspect displayed by signal S under these conditions over red over red.

Relays R and J 'are b oth energizedand:

relay H is energized in its normaldireotion.

therefore isyellow Relay G is also energized. sincefrelay H is energizedfin its normal direction to close contact 25- and since front contact 23 of relay G is also closedpa circuit is completed for relay Q Relay P is tie-energized, however, so that the current supplied to relay" Q energizesthis relay in its reverse direction. Relay P is energized,-but the main circuit for device L is open 'and'this device occupies "its effective a position. i With the apparasusat pointB in the condition in which it is illustrated in the drawing, the signals displays an: indication comprising yellow over green over red, thezsignal circuit passing from terminal X over. front contact 59 i of relay R wire 60, Windingv offrelaly'K wire" 61, front: contact 63 of relay G wire I62,

normal contact 70 of rela 'H wirel73 front contact 74 ofrelayiP wire 81, reverse conl tact 82 of relay Q wire 83, a green unit of" middle arm m of signal S wire 77; a yellow unit oftop arm t, wires 7 8 and 79, ;a red unit of bottom arm Z), and wire 80 to terminal Y Relays R rand- J associated "with section AfB are energized and relay'H 1s energized in the normal direction. JRelay Gr is therefore picked up. ".Since relay P is now energized relay Qfi 11s energized 1n the nor-1 mal directlon and relay P isfalso energized;

It will be seen, therefore, thattheflmaincircuit first traced for device L is now closed and that this device occupiesits ineffective Furthermore, a ;c1rcu1t is nowclosed for signalSf from terminalgX over front contact 59of relay R wirezfiO, wind-Q ing of relay-K -ywire 61, front contact 63 of relay GA, wire 62. normal contact 70 of relay H wire 73, front contact 74 of relay P I WireSl, normalcontact82 of relay,Q, wire ea, unit-of theitoparm tof signal S, wire85, red unit of the middlearm m, wires 5 5 86and79, a red unit of the bottomarmjbgand WireSO to terminalgY The aspect: displayed 1 Ot er-red? V. v a

describing-the circuits of the various signals, we have applied the same reference .characters to correspondingparts at each location to facilitateflcomparison of the signal; circuits at the several locations.

ditions a burned out light unit :will cause the corresponding signal to display the most restrictive signal indication. V

The trackway apparatus illustrated in Figs. 1 and 2 is suitable for cooperation with train carried governing means which is responsive to the positionsof the devices L located in the trackway. One for-mot train .-carried apparatus which will cooperate in this manner is illustrated in Fig. 3. In this view the reference character N designates an engine'mans brake valve of the usual and well known form for controlling the usual automatic brake applying apparatus on the train through the medium of the brake pipe 104. Associated with the valve N is an application slideva'lve comprising a piston 111 which is urged to an upper position by a ,f spring 113. Fluid under pressure, usually air, is constantly supplie'd'to'the upper side of. the piston lllfrom a sourceof'fiuid prev surenotshown in the drawing through" pipes 87 and 110. Pressure is also supplied to the I lowerside of piston 111, through a restricted orifice 112 in the piston. 1 The combined forces of spring 113 and the pressure on the lower side ofpiston 111 normally hold this piston, and the slide valve controlled therei by, in their upper positions, in which they are illustrated-in the drawing. Under these conditions, fluid pressure is supplied to the brake-pipe from pipe 87, through pipe 88, the

usualfeedvalve 89, pipe 90, port 91 in the enginemans brake valve, pipe 101, port 102 in the application slide valve, and pipe 103 to brake'pipe 104. The brake-pipe 104 isalso connected to chamber 97 beneath the usual equalizing valve 98 V The chamber 95 above therefore, the equalizing reservoir 96 is the equalizing valve 98 is constantly connected with an equalizing reservoir 96, and chamber 95'and reservoir 96 are both con nected through pipe 94, port 93 in the ap plication slide valve, pipe 92, and port 91 with pipe 90. ,Under normal conditions,

charged-and the same pressure exists on both sides-oftheequalizing valve 98 so that valve 99is closed. A reduction limiting reservoir i106 is connected, through pipe 107 and port 108 with atmosphere at port 109. A pipe 114 is constantly-connected with the chamber beneath the piston 111. When this pipe is vented to atmosphere, therefore, the pressure above the piston 111 over-balances the pressurebeneath this piston and moves the piston to a'lower position. WVhen this occurs, the elosingof port 102 disconnects the brakepipe from pipe 101. Furthermore, port 93 now'connects the equalizing reservoir with the reduction limiting reservoir and blanks port 109. The pressure in the equalizing 'reservoir is thereforereduced and the equalizing valve 98 moves upwardly to ven the brake pipe 104 through the restricted orifice 100, until the pressures on the two sides of the piston are equal, whereupon the valve returns toits original position to prev'entfurther bleeding of the brake pipe.

When the piston 111 is. in its lower position, port 116 connects pipe 114 through pipe 115 and port 116, pipe 117, and port 118 of the engineinaus brakevalve with atmosphere at pipe 119. The port 118 is open at all times except when the enginemans brake valve occupies the lap position. It follows that after the piston 111 has moved to its lower position to cause a brake application, the piston'remains in its lower position until the valve N has beenmoved to the lap position. The parts are so proportioned thatwhen the piston 111 moves to its lower position, the reduction'in brake'pipe pressure is such as to cause a service application of the brakes.

It should be noted that when the piston 111 occupicsits lower position it is impossible to charge the brake pipe through the enginemans'brake valve because pipe 92 and pipe 101 are both blanked at the slide valve controlled by the piston.

Pipe 114, which controls the piston 111, is in turn controlled by a valve device comprising a main valve 121 having its lower endterminating in a piston 123 and biased to the position inwhich it is shown in the drawing by a spring 122. l/Vhen' the valve is in this position, chamber 126 is discon nected from a passage 133 which leads to atmosphere. The valve 121 is hollow, and its lower end contains a pilot valve 128 which is normallyheld-closed'by a spring 127. The chamber 126 is connected with a reservoir 124 through holes 125 drilled in the valve 121,and the chamber 126 is also connected, through pipe 141 with a reservoir 120 and pipe 114. Under normal conditions, then, reservoir. 120 and reservoir, 124and, chamber 126 are allcharged with fluid pressure which is admitted'to pipe114through restricted orifice 112 in piston111. Under these conditions, the spring 122 holdsthe valve 121 in its lower position and valve 128 is also closed. 'The ,reference character 129" designates a plunger which is arranged to be moved upwardly when the train passes a trackway de-' i,

WVhenthe plunger'129 is moved upwardly,it engages the lower end of the pilot valve 128,

moving this valve against the bias of spring 127', andndmitting air from reservoir 124 through thehollow stem'of valve 121 to the chamber130 below piston 123. As a result, the piston123, and valve 121 carriedthereby,

-are forcednupwardly against the bias of spring 1122.

This movement of valve 121 closes holes 125 and traps the pressure in reservoir 124:. and chamber 130 thereby holding the piston 123 in its upper position. The

piston 123. carries a pivoted pawl'131 which is effective when the piston123 is in its upper position tohold the pilot valve 128 open. WVhen valve 121 is moved upwardly, chamber 126 is connected with atmosphere through passage 1553, thereby venting pipe 141 toatmosphere, and emptying reservoir 120 and the chamberbeneathpiston 111 of the application slidevalve. This operation'causes a service application of. the brakes in the manner already described. The pressure in reservoir 124 which is trapped by the movement of valve'121 upwardlyto close holes 125, holds thepiston 123 in its upper position long enough to'insure that the reservoir 120 is completely discharged. The pressure trapped inreservoir 12 1 gradually leaks oil, however, through the guides of the valve 121 and the pilot valve 128,- andafter theexpiration of i a time interval, spring 122again restores the valve 121 to the position in which it is illus- V trated in the drawing, thereby allowing valve 128 to close. If, now the engineman moves valve N to the lap position, pressure from pipe 110 passes through the restricted orifice 112 in piston 111 and gradually charges reservoirs120 and 12 1. After the expiration of a time interval, such for example, as 15 seconds, the pressure below piston 111 is increased to a sufficient value, to permit this pressure plus the effect of spring 113 to restore the piston 111 to the position in which it is illustrated in the drawing thereby connecting the reduction limiting reservoir 106 to atmosphere, and res-charging the :brake pipe to itsoriginal value.

Itwilllbe plain from the foregoing that when. the train passes a trackwaydevice. L

in its effective position, the operation of plunger129 initiates a service application of the brakesand that this automatic application can be released only after the expiration of thetime interval requiredto charge reser= voir120 and return piston 111 to itsupper position. If, prior to the restoration of the piston .111 to its upper position, the train passes a second trackway device L in its effective position, the plunger 129 is again raised, and again ventsthe reservoir 120 to atmosphere sogthat the time interval requiredlto charge reservoir-120 is re established. follows that thebrakes canbe released only at the expiration of the full time interval of 15seconds after t-hela'st actuation of the valve 128 by a trackway device L.

Referring now alsozto FigsJl and 2,;we

-will assume thata train providediwiththe apparatus illustrated in Fig. 3 passes through the stretch of track shownin Figs. 1 and 2. WVhen this train passes device L the plunger 129 is notoperated because thisdeviceis in its ineffective position. I When the train enters section LA-B, relay R becoines de-energized, thereby causing the de-energizationofrelays H G Q}, andP andcausing signal S to display a stop indicationsimilar to that illustrated in the drawing at signal S, that is", red over red over red. Furthermore, the circuit for device L is now interrupted and with only'the apparatusthus far described this device would move to'its efiective position. With systems ofthe type described it is not unusual to operate trains consisting of two or more cars each provided with apparatus similar to that illustratedin Fig. 3. "Under theseconditions it would be undesirable to have the device L cooperate with plunger 129 on each of-the cars except the first car, and we therefore provide means; for holding the device Lin its ineffective position until the rear of the train haspassed the device, providing the devicewas in its ineffective position when the train approached the device. This is accomplished by means of an auxiliary circuit for each device L controlled by the associated relay J. For example, when the train passed joint 2 in approaching point A, relay J A becamefde-energized. Since decontact 51 was closed anda circuit was'closed for device L from terminalX over" back contact 19, of relay J, wire 50, contact 51,

wires 52 and 48, and operating mechanism of device L to terminal Y VVhen the train enters section A 13," therefore, the main operating circuit for device L isopen butthe device is held in its inefiective position by virtue of the circuit just traced, until the rear of the train has passed out of the section to the left of point A.) When thetrain passes point B, devicegL which nowoccupies its effective position, lifts plunger l29 *onthe' train and initiates aserviceapplication ofthe brakes. Furthermore, the plunger 129 issuecessively operated as the train passes devices L2, L ,and L I The lengths of the track sec tions 'are'so chosen and the severity ofthe service application. of the brakes caused on board the train is so regulated thata't-rain travelling at the maximum permissive speed a will be brought to a full stop. beiore reaching pointF. Furthermore, thetraincarried apparatus issol proportion that ii -attain travelling atthe maximum speed passes point B should'incura brakeapplication, the time interval required to release the brakes, will be so long that successive operations of the application of the brakes Will-have so'deceleratedthe train that the time required to vcharge the reservoir 120 will be consumed before the train reachespoint F The engineman may then release the brakes by moving his valve Nto the lap position. Butunder these conditions, since the brake application has, endured since the train passed point B, the train speed willbe so reduced that it will be safe to proceed-at the low speed atwhich the train will then be operating. I

With only the apparatus thus far described, it will. be seen that no-matter how low the speed of the train, the train will-receive an automatic application ofthe brakes assoon as it proceeds within four tracksections' of a hazard here represented by train Z. In systems which must accommodate-a large volume of traflic, this feature is undesirable, because it increases the headway, or'minimum safe distance between trains. For this reason we have provided means for each section effective when the main operating circuit for the associated track device L is open, to move the device to its ineffective position up'on'the approach of a train moving ata speedless than that of the maximum speed fro-mwhich a'continued service brake application can bring the train to a full stop short of the hazard which has caused-the unsafe tralfic conditions that opened the main operating circuit for the device L.

In order to accomplish these results, we provide each section with four timing relays designated by reference characters '1, U, V, and'W, respectively, with exponents corresponding to the location and controlled in parallel-by a backcontact 136 of the associated relay J. All of the timing relays are therefore normally de-energized but when a train passes the point of connection of transformer 5 to de-en'ergize the relay J, the corresponding timing relays are all'energi'zed. All of the timing relays are slow acting, however,

so that an interval of time elapses after the de-energization of relay J before these relays elose their front contacts; Furthermore, the four timing relays for each section require different times for their operation so that the I relays close their contacts insuccession: The

parts are so1.'proportioned*that the time required for theoperation of each relay T is slightly lessthan that required-for a train travelling at some lowspeed, such as'1'0 mil'es per-hour, to travel-from the insulatedjoint 2' to the adjacent trackway device-L. Insimilar manner, the time interval required for each relay U to close its front contact is slightly less than the time required for a train travelling at asomewhat higher speed,

example, as miles such as 20 miles per hour, to traverse the same distance. In similar manner, relays V andVV at each location are'adjusted to. correspond to different high speeds, such for per hour and miles perhour, respectively. 1

Assuming, now,that the train passing device L is travelling at the maximunrpermissive speed, such for example as miles per hour, this tram Wlll lncur a service application of the brakes at point B and-the repeated operation of plunger 129v by devices L L and L will cause this application of the brakes topersist to bring the train to a stop before it reaches point F. e will next assume, however, that the train approaching point B is traveling at a lower speed, such for example, as 35 miles per hour. :Under these conditions, the timingrelay VV becomes energized before the train reaches point B and a clrcult 1s then closed from terminal X over front contact 33 of relay RB, wire 34, front contact 35 of relay G wire 36, normal contact 37 of relay H wire 38, front contact 39 of relay P wire 40, reverse contact 41 of relay Q Wire 142, front contact 143 of relay WV wires 14 4, 43, 44, 45, 46, '47, 48, and

. operating mechanism of device L to terminal Y It will be plain, therefore, that-even though traffic conditions in advance are unsafe, the'device L will be moved to its ineffective position to prevent an'application of the brakes if the speed .of the train is be low a predetermined safe speed.

In similar manner,'when the train passes device L this device will be held in its ineffective position if the train speed is below a safe value, but this value is now determined by the timing of relay V the circuit for device L passing from terminal X through front contact 33 of relay R wire 34, front contact 35 'of relay G wire 36, normal contact 37 of relayH wire 38, back contact 39 of relay P wire 145, front contact 146 of-relay V wire 147, 44, 45, 46, 47 and 48, and operating mechanism of device'L to terminal Y It will therefore be plain that if the train approaching point C is travelling at a speed below 30 miles per hour the device'L will be moved to its ineffective position be fore the train passes this device so that no automatic application of the brakeswill result. In similarinanner, a circuit is'prepared at point-D from terminal X over front contact 33 of relay R wire 34, front contact 35 of relay G wire 36, reverse contact 37 of relay H ,'wire 160, front contact 148 of relay U .-wires 45, 46, 47, and 48, and operating mechanism of device L to terminal Y This circuit is closed when relay U beceme's energized. This'can, of course, happen only if the speed of the train approaching point D is below the value for which the'relay U is points in the section.

point E is moving at a speed belowthe value determined by timing relay T the energization of this relay completes a circuit for the device L including front contact 33 ofrelay R back contact 35 of relay G and front contact 149 Off relay T It will t rere'fore be plainthat at each location the tra clrway device L is so controlled that under unsafe tratlic conditions, a train approaching the hazard whichcauses unsafe traliicconditions may proceed Without incurring anapplication of the brakesto a point located at, a distance in rear of this hazard which depends upon the speed of, the train and is equal to the distance required to bring the train to a full stop short of the obstruc tion. a .i a I y [By making the maximum length of each section only a comparatively small partof themaximum braking distance and by initiating the automatic application at several sections in rear of an occupied section, we have produced a system which permits a material reduction in the headway required for the safe operation of trains.

Under some conditions of operation it may be desirableto ar 'ange the apparatus to en sure that the speed of the train does not exceed some maximum value. This may be accomplished with the apparatus shown in Fig. 4. In this view the lining relay T is controlled by relayd in such manner that relay T becomes energized when a train is a; preaching point B if the train is travellingat a speed below the maximum permissive speed. With this arrangement, it traific conditions in advance are sale, a circuit is completed for the operating mechanism of device L over front contact 150 oi relay P normal con tact 1.51 of relay Q andrliront contact 1520f relay T so that the device is moved to its ineffective position before the train passes the device. If, however, the speed of the train exceeds the maximum permissive speed for which the timing relay T? is adjusted, the device L will be in its effective position when the train passes the device and an automatic application of the brakeswill result. Furthermore, an automatic application of the brakes will result if a train passes point B when traffic conditions in advance are unsafe, the control of the variousrelays located at point B being the same as has already been described in connection with Fig, 1;

It is also sometimes desirable to arrange the apparatus to ensure that a train moving through a section immediately in rear of an occupied section shall not proceed at speeds greater than a predetermined low value. To accomplish this result, the section A'B is provided, in Fig. 4, with two relays J and J receiving energy from transformers 5 and 5 connected across insulated joints 2 at spaced 7 Relay J controls a timing relay T Relay J 2 controls a timing relayT". The two timingrelays T andJIl conrtol the trackway devices L and L which are similar to the other devices .L liereinbefore described. Device L? is normally held in its inefiectiveposition byvirtue f a cir-' tions, then, devices L andL are at alltimes held their ineffective position: fWhenthe sect on totheright olrpoint B is occupied, however, relay B asdeenerginecl and the circuits just described} for trackway devices L and L are then open. \Vhen timing relay T is energized, current; is supplied to device L over itslrontlcontact 155 and the parts are so proport oned andlarranged that if a trainv approaching device L is moving-at a speed below a predeterminedlow value, relay T will become energized after this train passes the insulated joint 2? associated with relay J? and before the train reaches device L As a result, the device iwillgbemoved to its ineffective position and noautomatic ap; plication of the brakes will result. Further? morethe closingof relay-Th completes a circuit for device L including front contact 155 of relay T and front contact 154 ofrelayJ When a the train passes relay J this relay becomes de=energized and opens thecircuit for device L at frontcontact 154 ofrelay J At the same time, relay T isset into operation and vif the speed of the train is below the predetermined low value, front contact 156 of relay '1 closes to move device L to its ineffective 7 position before the train reaches the device. 7 a 1 1 1 1 y, 7 For purposes of explanation we have shown and f described our invention applied toa fiv'e-block-signaling system} but it should be understood that ourinvention is not limited to this particulararrangement."

Although we have herein shown anddescribed only two forms of railway tralfic controlling apparatus embodying ourinvention, it is understoodthat variousachan'ges and modificationsmaylbe made therein within the scope ofthe appended claims without departing from the spirit andscope of our invention, 15 of El, Having thus describedour invention, what we claim is: 1; H 1 1. Railway ,tralfic controlling apparatus comprising train carried mechanism arranged when actuated to cause an application pf the brakes, means on the train forpreventmg release of the brakes until the expiration of a predetermined time interval following the last actuation of said'mechanism; and means located 1n the trackway andopera ing under unsafe tralfic conditions to cause reQ peated actuationsof said mechanism at fiance intervals so short that the train win-is;

broughtsubstantially to a stop before the -brakes-can be released. j g 7 )2, Railway 'trafiic controlling apparatus comprising train carried mechanism ar- "ranged when actuated to cause an application of the brakes, means'on the trainfor preventing release of the brakes until the expiration of a predetermined time interval following thelast. actuation of said mechanism, and tripping "devices located at intervals along the trackway and each arranged to actuate saidm'echa'nism when a train passes such device "under dangerous traffic conditions, said time interval'and the distances be tween said devices beingso related that after 'ab'r'ake application has been efiected the brakes can be-released only if the speed of the train is below a predetermined value.

Railway t'raflic. cont-rolling apparatus comprisingtrain carried mechanism arranged when-"actuated 'to'cause an application of the brakes, means on the train for preventing release of the brakes until the expiration'o f a'predetermined time interval following the last 'actuationfof-said mechanism, and'a plurality of tripping devices located at intervals along the trackway and each'effective under dangerous traffic conditions to actuate sa'id mechanism, the "distances between "adjacent ones of saiddevices being less than the distance traversed during said time interval by a traintravel'ling at more than a predetermined low speed; g

4. In combination, a section ,ofrailway track, a source ofenergy connected across the rails adjacent one end of the section, an insulated joint in one rail of the section, a winding connected across said joint, a slow acting device located in the trackway and controlled by said-winding, a'tripping device also located the traclcway and controlled in part'by s'aid slow acting device, and train carried goverm g means controlled in part by said tii'ppinsnevice. V g

"5,111 combination, a section of railway track, a source of energy connected with the miisadjacent one end of the section, an n sulate'd joint'lo'cated at anintermediate. point in one rail of the section, a winding connected across said joint, a"slow acting device located at one enact the section and controlled by saidv Winding, a tripping devlce al's'e-loeated in the trackway and controlled in part by said slow acting device, train car'- ans a'ctiiated'at times by 12f tron 0re 7 6; In'ctifirbinati w v isechaa in, inea-njs located in the trackway for at times controlling said gavmechanism, a plurality of time measunag devices having different time eien'iefits and all set into operation when a train passes a point a measured distance in rear of said means, and apparatus for controlling said means by a different one of said time measuring devices depending on traflic conditions in advance. 7

7. Railway trafiic controlling apparatus comprising train carried mechanism arranged when actuated to cause an application of the brakes, means on the train for preventing release of the brakes until the expiration of a predetermined time interval following the last actuation of said mechanism, means located in the trackway for actuating said mechanism when the train approaches a hazard within the distance required for a brake application to bring the train to a stop, and means for repeatedly actuating said mechanism as the train approaching such hazard traverses distances smaller than that which the train could traverse in said time interval.

8. In combination with a stretch of railway track, a tripping device biased to an effective position and having operating mechanism to move the device to an ineffective position, a circuit for said operating mechanism closed only under safe traffic conditions, time measuring means set into operation when a train approaching said device passes a predetermined point, means controlled by said time measuring means for at times supplying current to said operating mechanism under unsafe traificvconditionaand train carried overning means controlled by said device.

9. In combination a section of railway track, a tripping device located adjacent the exit end of said section, and biased to an effective position, means for holding said device in an ineffective condition when traffic conditions in advance of said section are safe, a source of energy connected across the rails adjacent the exit end of such section, an insulated joint in one rail of said section, a transformer having a primary connected across said joint, a first relay receiving energy from the secondary of said transformer, a slow acting relay controlled by said first relay, means controlled by said slow acting relay for at times moving said device to its ineffective condition when traffic conditions in advance of said section are unsafe, and train carried governing means controlled by said device.

10. In combination, a section of railway track, a-tripping device located adjacent the exit end of said section, and biased to an effective position, means for holding'said device. in an ineffective condition when trafiic conditions in advance of said section are safe, a plurality of normallyopen contacts, means set into operation when a train approaching saiddevice passes a predetermined point and operating, to close said contacts at the exas the home repeater relay for the next section in advance is energized or de-energized respectively provided the track relays associated with said home relay and with the section next in advance are both energized,

means for energizing each home repeater re lay When the associated home relay is energized in either direction, a polarized distant relay and a distant repeater relay for each section, means for energizing each said dis tant relay in the normal or reverse direction according as the distant repeater relay for the section next in advance is energized or deenergized respectively provided the home relay for such section in advance is energized in the normal direction, means for energizing each distant repeater relay when the associated distant relay is energized in either direction, and a signal. for each section controlled by all of the associated relays.

12. In combination, a section of railway track, a source of energy connected across the rails adjacent one end of the section, an insulated joint in one rail of the section, a winding connected across said joint, a tripping device located in advance of said joint, a relay receiving energy from said winding, and means controlled by said relay and by traffic conditions for controlling said device.

13. In combination, a section of railway track, a tripping device adjacent the exit end of said section and normally occupying its effective condition, means efiective under safe traiiic conditions and operating when a train is approaching said device to-move the device to its inefiective position provided the speed of said train is below a predetermined value, a second tripping device located at an intermediate point in the section, means operating under safe traffic conditions to hold said second device in its ineffective position, and means set into operation by a train approaching said second device for moving the device to its ineffective position provided the speed of such train is below a predetermined lower value.

14. Railway traific controlling apparatus comprising a stretch of railway track divided into a plurality of successive sections, train carried mechanism arranged when actuated to cause an application of the brakes,

means on the train for preventing release of the brakes until the expiration of a predetermined time interval following the last actuation of said mechanism, apparatus for each section for actuating said mechanism when a train enters the section under unsafe traflic conditions, said time interval and the lengths of said. sections being so related that after a brake application has been caused the brakes can be released only if the speed of the train is below a predetermined value.

In testimony whereof we afiix our signatures.

HAROLD S. LOOMIS. HOWARDA. THOMPSON.

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