US2891143A - Highway crossing protection control apparatus - Google Patents

Description

June 16, 1959 R. R. KEMNIERER ETAL 2,891,143

HIGHWAY CROSSING PROTECTION CONTROL APLPARATUS Filed Aug. 28, 1953 i 2 Sheets-Sheet 1 1, m m k f a a 5" E 5 55 s: 5

INVENTORS. fialplzRlmmel'er and Lucas A. Damasio MAW THEIR A T TORNE'Y' June 16, 1959 V R. R. KEMMERER ETAL 4 HIGHWAY cnossms PROTECTION CONTROL APPARATUS Filed Aug. 28, 1953 2 Sheets-Sheet 2 Fig: 2

INVENTORS.

Rdlplz ll Kemerez' and Lucas A. Damasio 7 BY ZU /M THEIR A'TT EY 2,891,143 Patented June 16, i959 2 ,891,143 HIGHWAY CEQS'SING PROTECT'IDN GONTROL APPARATUS Ralph R. Ken'inierer, Swis'svale, and Lucas A. Damasio, Wilkinsburg, Pa., assiguors to Westinghouse Air Brake 'Conip'an'y, Wilmerding', Pin, a corporation of Pennsylvanla A plication August is, 1953, serialNo. 377,222 9 Claims. cre m-130' 0hr inventioh'relates 'to highway crossing protection control apparatiis, and in particular to apparatus for controlling crossing gates at a highway-railway grade cross- At points where railways and highways intersect at grade, it is often desirable to provide highway crossing gates to prevent highway trafiic from crossing the intersection when a train is appro'aching. In the past it has been common practice to provide two sets of gates, one set on each side of the intersection, and when a train enters the track section including the highway crossing, all the gates will become lowered. With all four gates being lowered at the same time, there is a possibility that an automobile traveling along the highway might be trapped between the two sets of gates.

In order to avoid this possibility, some crossings have been porvided withonly two gates, one on each side to prevent vehicle trafiicfrom entering the intersection but not barring exit from the intersection in the event that the gates should be lowered "while a vehicle was on said intersection. Such an arrangement, however, will not prevent pedestrians from attempting to traverse the crossing.

Accordingly, it is an object of our invention to provide highway crossing protection control apparatus which will prevent pedestrians from traversing the crossing when the gates are lowered and will not trap vehicles between the gates in the event that thegates become lowered while a vehicle is on said crossing.

Another object of our invention is to provide apparatus which will cause the traffic gates, that is the gates which obstruct entrance to the crossing, to commence moving to their horizontal position prior to the lowering of the non-trafiic gates, that is the gates which obstruct exit from the crossing, so that any traffic which has entered the intersection just prior to a train enteririg the track section inchidin'gthe intersection will be able to pass through the intersection before the non-trafiic gates are lowered to bar the way. p

A further object of invention'is to provide apparatus which will cause magma-trams :gates to commence rising prior to the traffic gates so that the highway will be unobstructed when the traflic gates rise to permit highway name to enter the crossing.

Still a further object of .our 'inventionis to provide apparatus of the type described in which alhighway crossing signal will be actuated prior to the traflic gates being lowered so as to 'warn oncoming frame 'of the appreaching train. a

Yet another object of onrfinvention is to provide circuits which will check the integrity of our-highway crossing control apparattis and will actuate the highway crossing signals in case certain circuit elements are notoperating properly. I

According t'o our invention we provide slow p clclip re lay means which becomes deener'gized when a train enters a track section which is intersected by a .h'ig'hway. Upon the release of the slow-piclt'tip' relay means the mechanisms controllingt'he gates which obstruct entrance 2 to the crossing, that is the trafiic gates, become deepergized and the traffic gates commence moving to their horizontal position, When the traific gate mechanisms become deenerg'i zed, a sloW-release relay means will become deenergized and, upon the release of this slow-release relay means, the mechanisms which contro1 the gates obstructing exit from the crossing, that is the nontraffic gates, commence moving to their horizontal posison- When thetrain vacat'es the crossing section the slow release relay means picks tip and the non-traffic gates commence moving to their verticjel position. Also hpon the trhin vacating the crossing section, the slow-pickup relay means becomes energized and, when this relay ineans pick's up, the traflie "gates comme-rice moviiig to their vertical position. We "ftirthe'f provide circli it means for controlling a highway 'crossin'g',si'ghal. This circuit means is'so arranged that the highway dressing si'gnel becomes energized upon attain occupying the crossing section. We furtherprov'ide means in the circuit means for controllin'gth'e highwayc'ros'sin'g signal for checking the operation of the slow-release relay means and, if this is not operating properly, the crossing signal will become energized, so as to warn maintainers that the apparatus is not functioningp'roperly. v 7

Other objects of our invention will appear hereinafter as the characteristic features of construction and mode of operation or our invent-ion are described in detail.

We shall describe two formsoi onr invention and shall then point out thesis/e1 features therein in the claiins.

In the accompanying drawings, Fig.1 is a diagrammatic "view showing one circuit arrangement embodying our invention;

Fig. 2 is a diagrammatic View of a second circuit arrange'ment embodying olir invention.

Referring now to Fig. l, a stretch ofrail-way track made up of the t-rack rails and 2 is divided into track sections IT and 2T by insulated joints 3. Track section 1T is provided with a track circuit i-rlclhding a track battery TB and a track i elay 1TB; Relay MFR controls a slow release relay 'DPR which turn cofitrols a slowrelease, sloW-picktip relayTZR, Relay TZR ontrols the gate mechanisms foria :pair of traffic gates A a d 5 which, when in ,a horizontal position obstruct entrance to the intersection of a highway H and :the st fietc'hof railway track. Relay 'TZR controls another series of cascade connected slow-release relays 'TZPR, TZJPPR and TZZR. Relays 2TB, TZ'R, TZPR, TZPPR and TZZR joi-nt-lycom trol the gate mechanisms for a pair of iron- traffic gates 6 and 7 which 'when-intheir horizontal position, obstruct exit from the intersection. Also provided is a crossing relay XR which controls highway crossing signals CS which may be flashing light signals or, as here shown; bells. r

As here shown, ,the direction that traffic is to move over the stretch is the direetionindicated by the arrow. By the use .of additional conventional circuits, the :same circuit arrangement can be made to .operate for a stretch over which traffic can move in two directions, by sub stituting a control relay for ,relay iTR and having this control relay controlled jointly by track relays associated with the two approach sections to .the intersection and associated stick relay, or by the use of an interlocking relay in accordance with well known practice.

As shownin l, I116 afiprtams i P a i" mal eondition. Track Isis-y HR i energized by the trakbattery over the track ircuit and its contacts therefore picked Accordingly, may TPR ."h picked up by circiiit which may be traced the positive terminal B of a battery LB, over front con-tact a of relay lTR, and the winding of relay TPR to the negative terminal N of battery LB. With relay TPR picked up, relay TZR will be energized and its contacts picked up by a circuit which may be traced from positive terminal B of battery LB, over front contact a of relay TPR and the Winding of relay TZR to negative terminal N of battery LB. Accordingly, the gate mechanisms for gates 4 and 5 will be energized by a circuit which may be traced from positive terminal B of the battery LB, over front contact a of relay TZR, and the gate mechanisms 4 and 5, in multiple, to negative terminal N of battery LB. The gate mechanisms may be of any suitable type. For instance, they may be similar to that shown and described in Letters Patent of the United States No. 1,138,087, granted on May 4, 1915, to John P. Coleman for Railway Signals. In the gate application, the gate arm is an extended form of the semaphore of the patent. With the gate mechanisms for the gates 4 and 5 so energized, gates 4 and 5 will be held in a vertical position and highway traffic will be able to enter the intersection.

With relay TZR picked up, relay TZPR will be picked up by a circuit which may be traced from positive terminal B of battery LB, over front contact b of relay TZR, and the winding of relay TZPR to negative terminal N of battery LB. With relay TZPR picked up, relay TZPPR will be energized by a circuit which may be traced from positive terminal B of battery LB, over front contact a of relay TZPR, and the winding of relay TZPPR to negative terminal N of battery LB. Accordingly, re lay TZZR will be energized by a circuit which may be traced from positive terminal B of battery LB, over front contact a of relay TZPPR and front contact 0 of relay TZR and front contact b of relay ITR, all in multiple, and the winding of relay TZZR to negative terminal N of battery LB. With the circuit arrangement as shown, the gate mechanisms for llOn- tI'afl'lC gates 6 and 7 will be energized and the gates will be held in their vertical position due to energization by a circuit which may be traced from positive terminal B of battery LB, over front contact a of relay TZZR and front contact b of relay TZPPR and front contact b of relay TZPR and front contact d of relay TZR and front contact 0 of relay 1TR, all in multiple, and gate mechanisms for gates 6 and 7 in multiple, to negative terminal N of battery LB. Control relay XR will be energized by a circuit which may be traced from positive terminal B of battery LB, over front contact d of relay lTR, front contact 0 of relay TZPPR, front contact b of relay TZZR, and the winding of relay XR to negative terminal N of battery LB. Accordingly, the crossing signals CS will be deenergized because their obvious energizing circuits will be open at back contact a of relay XR.

Having thus described the circuit arrangement shown in Fig. 1 in its normal condition, let it be assumed that a train enters section 1T from the left and traveling in the direction indicated by the arrow.

As the train enters section 1T, the Wheels and axles of the train will shunt relay lTR causing it to release. When relay ITR releases the energizing circuit for control relay XR will become open at front contact d of relay lTR and control relay XR will release. Accordingly, the crossing signals CS will commence operating. When relay 1TR releases,the energizing circuit for relay TPR will become open and a snubbing circuit for relay TPR which includes back contact a of relay ITR Will become closed. This snubbing circuit prolongs the release time of slow release relay TPR. After the expiration of a period of time, relay TPR will release and open the energizing circuit for relay TZR and close a snubbing circuit for relay TZR including back contact a of relay TPR. Relay TZR will not immediately release because of its slow release characteristic but, upon relay T ZR releasing, the energizing circuit 'fQ the gate mechanisms of traffic gates 4 and 5 will become open at front contact a of relay TZR and gates 4 and 5 will commence moving by gravity to the horizontal or obstructing positions.

When relay TZR releases, the energizing circuit for relay TZPR will become open and a snubbing circuit for relay TZPR including back contact b of relay TZR will become closed. Because of the slow'release characteristic of relay TZPR, its contacts will not immediately release upon deenergization but will remain picked up for a predetermined period of time. Upon the release of relay TZPR, the energizing circuit for relay TZPPR will become open and a snubbing circuit will be established for relay TZPPR including back contact a of relay TZPR. However, the contacts of relay TZPPR will not immediately release due to its slow release characteristic.

With relays ITR and TZR released, two branches of the energizing circuit for relay TZZR will be open, that is the branch including front contact b of relay 1111 and the branch including front contact 0 of relay TZR. Upon the release of the armature of relay TZPPR, the third branch of the energizing circuit of relay TZZR will become open and relay TZZR will become deenergized. The contacts of relay TZZR will not immediately release due to the slow release characteristic of relay TZZR. However, when they do release, all the branches of the energizing circuit for the gate mechanisms of non-traific gates 6 and 7 'will be open and gates 6 and 7 will cornmence to move to their obstructing positions. It should be obvious that the traffic gates 4 and 5 will commence lowering before the non-traffic gates 6 and 7 start moving to their horizontal position. Therefore, any traffic which has already entered the intersection prior to the lowering of the traffic gates will be able to move through the intersection and out again to the highway without being obstructed by the non-trafiie gates. It is also clear that With the crossing signals CS in operation prior to the lowering of the traflic gates 4 and 5, traflic will be adequate warned of the approaching train and no traffic will be trapped on the intersection by the time the non-- traffic gates are lowered to bar exit from the intersection.

Upon the train vacating section IT and entering section 2T, track relay lTR will pick up, and thereby recnergize the gate mechanisms for the non-traflic gates t5 and 7 over a branch of their energizing circuit which may be traced from positive terminal B of battery LB, over front contact 0 of relay lTR and the gate mechanisms of gates 6 and 7 in multiple, to negative terminal N of battery LB. Accordingly, gates 6 and 7 will commence moving toward their vertical or non-obstructing positions. Relay TZZR will also pick up upon the picking up of relay lTR due to its energization by a circuit which may be traced from positive terminal B of battery LB, over front contact b of relay 1TR, and the winding of relay TZZR to negative terminal N of battery LB. At the same time the energizing circuit for relay TPR will become reestablished and that relay will pick up. When relay TPR picks up, the energizing circuit for relay TZR will be reestablished and after a time delay due to the slow pick up characteristic of relay TZR, it will pick up its contacts and reenergize the gate mechanisms for fic gates 4 and 5 which will commence moving to their vertical positions. When relay TZR does pick up the energizing circuit for relay TZPR will be reestablished. Therefore, relay TZPR will pick up and reenergize the winding of relay TZPPR which will also pick up. Upon relay TZPPR picking up, the energizing circuit for relay XR will become reestablished and the crossing signals CS will become deenergized. In this manner the circuit arrangement will be restored to its normal condition.

It should be noted that upon relay lTR picking up, the non-trafiic gates 6 and 7 will commence moving to their vertical positions whereas the traflic gates 4 and 5 not commence moving to their vertical positions until 'trains presence throughout the train movement.

after a time delay adorned bythe slow niekn eharacsection. Of course, it can he provided that the traific gates will commence moving to their vertical position simultaneously with the 'non trafiic gates by using a slow release ordinary pick up relayas relayTZR. However, the staggere'd raising of the gates is desirable because it eliminatesthe necessity of' batterylB supplying starting current for all the gate mechanisms simultaneously,

Another feature upon the train clearing the crossing secti'on IT is that the crossing signals CSwill continue to operate until after both "sets of gates have commenced rising, so as to give a continuous safe indication of a This result is achieved because, inthe sequence of events which take place as the circuit arrangement becomes restored to its normal condition, relay TZPPR will be the last relay to pickup and since front contact'c of relay TZPPR is in the energizing circuit forthe control relay XR, con

trol relay XR will not pick up until after the remainder of the circuit arrangement has been restored to itsnormal position. Therefore, the crossing signals CS will not cease to operate until after the remainder of the circuit arrangement has been restored to its normal position.

Assuming now that after the train clears the intersection and all the gates have commenced moving to their vertical position, a second train enters section 1T. Relay 1TR will release, thereby deenergizing relay XR. Accordingly, the crossingsignals CS Will immediately reconimence operating. However, the gates will continue moving toward their vertical positions until. the relays sequentially release as has already been described and, therefore, the traffic gates will release prior to the nontrafiic gates.

However, if the second train enters the section when only the non-traffic gates are rising, the release of relay 1TR will immediately open the only energizing circuit then closed for relay TZZR and relay TZZR will immediately release and deenergize the gate mechanisms for thenon- traffic gates 6 and 7 which, accordingly, will immediately reverse their direction and commence. moving to their horizontal positions. Thetraflic gates 4 and 5', under these conditions, will not move from their hori zontal position. t

In either case it will be apparent that traflic cannot be trapped on the intersection when both sets of gates finally return to their obstructing position.

The circuit arrangement as shown in Fig. 11 is provided with several desirable safety features to provide against failure of several elements in the circuit arrangement. Incase the. energizing. circuit for relay TZPR becomes open for any reason and thereby causes relay TZPR to release, relay TZPPR will also release, as explained in the normal, operation of the circuit. However, relay TZZR-will not release due to the fact that relay ITR and relay TZR will stillbe picked up and, therefore, two of the branches of the energizing circuit for relay TZZR will remain. closed. Accordingly, when the track relay ITR releases, relay TZZR will be unable to release until after relay TZR releases. Therefore, non-triaffid gates 6 and 7 will. not commence moving to their horizontal position until after the trafiic gates 4 and 5 commence moving to their horizontal position. Furthermore, if. a

wire in. the encrgizingcircuit of relay TZPPR becomes broken, relay TZPPR. will release but relay TZZR will rc-- main picked up due to the fact that two branches of its energizing circuit will. still remain closed. and, therefore, non-trafiic gates 6 and. 7' will not commence to move to their. horizontal positions until. after relays ITR, TZR and. TZPR release. In the event that the energizing circuit for relay TZZR becomes open the non-traflic gates 6- and 7 will not commence to move to their horizontal positions until after relay TZPPR releases. In the event that the energizing circuits for relays TZPR, TZPPR and TZZR were all to become open, the non-traffic gates will commence moving to their horizontal position upon the release of relay T ZR which will be simultaneous :with the traffic gates moving to their horizontal position. In any of these above instances relay XR will become deenergized and the crossing signals willoperate. But as already shown, the crossing gates will remain in their vertical positions. Therefore, maintainers will be given a positive warning that something is wrong with the circuit arrangetnent.

Referring now to Fig. 2, a second embodiment of our invention is shown. In this second embodiment, relays T ZPR, TZPPR and TZZR, as shown in the first embodiment, are replaced by a single capacitor snubbed relay TZZR which will have a release time substantially equal to the release time of the series of cascade connected relays TZPR, TZPPR and TZZR, as shown in Fig. 1. The energizing circuit for relay TZZR andcapacitor C is obvious from an inspection of Fig. 2 and includes front contact b of relay 1TR in multiple with front contact 5 of relay TZR. When this energizing circuit becomes open; capacitor C will discharge through the winding of relay TZZRand that relay will remain picked up until capacitor C has discharged sufliciently to cause it to release.

In operation, when a train traveling from left to right enters the section 1T, the wheels and axles of the train will shunt the track relay 1TR causing it to release and open the energizing circuit for the relay TPR and close a snubbing circuit. for relay TPR including back contact a of relay ;1TR, Due to theslow release ch'aracteristic of relay TPR, it will not immediately release but when it does release it will open one branch of the energizing circuit for nondrafiic gates; 6 and 7. Furthermore, upon relay TFRreleasihg, it will open the energizingcircuit for relay TZR and close a snubbing circuit for relay TZR including. a back contact a of relay TPR. After a tirne delay due to the slow release characteristic of relay TZR, it will release and open the energizingcircuit for the gate mechanisms of the traffic gates 4 andS and accordingly, the traffic gates will. commence moving to their horizontal position. Also, upon the releaseof relay TZR the energizing circuit for slow release relay TZZR will open, but due to thepresence of capacitor C across the winding of relay TZZR, relay TZZR will. not release immediately; Not until capacitor C has discharged sutficiently through the winding of relay TZZR so that the voltage across capacitor C becomes equal to the release voltage of relay TZZR will relay TZZR release. Upon its release, all the branches of the energizing circuit for the gate mechanisms of the non-tuafiic gates 6 and 7 will be open and the non-traflic gates will commence moving to their horizontal position. In a manner similar to that described with reference to Fig. 1, control relay XR in Fig. 2 will release upon the release of track relay 1TR and crossing. signals CS will be operating from the time the track relay lTR releases until, as will presently be shown, relay TZR picks up. p l

Uporrthe train vacating section 1T, the track relay lTR will pick up but relay XR will continue to be re: leased. due to the fact that its energizing circuit will be openedat front contact I: of relay TZZR and frontcontact d of relay TZR. Accordingly, the crossing signals CS will continue to op rate. Withnelay lTR picked up, relay TPR- will once more becomeenergized and will pick. up thereby closing. the branch of the energizing circuit for non-traflic gates 6 and 7 including front contact 12 of relay TPR. Relay will once more become energized by a circuit which maybe traced fromthe positive terminal B oft-hebattery LB, over front contact b of track relay 1-'ITR,i and the winding of relay TZZR to the negative terminal N of battery LB. Accordingly, relay TZZR will pick up and thereby reestablish another or the branches of the energizing: circuit for the nori= tratfic gates 6 and 7. The non-traffic gates will commence moving to their vertical positions immediately upon the picking up of relay lTR, since they will be energized in multiple by a circuit including front contact c of relay ITR. The traific gates will not commence moving to their vertical positions until after relay TZR has picked up and since relay TZR will not pick up until after the time delay afforded by the slow pick up time interval of relay TZR has expired, the traffic gates will not commence moving to their vertical positions until after the non-traffic gates have commenced moving to their vertical positions. Upon the picking up of relay TZR, control relay XR will pick up and crossing signals CS will cease operating and, accordingly, the circuit arrangement will be restored to its original condition.

It should be clear that if a second train enters section 1T while the gates are moving to their non-obstructing positions, no unsafe condition can arise in which traflic will be trapped on the intersection.

In case relay TZZR should become deenergized for some reason, such as one of the leads to the winding be coming opened, relay TZZR will release but the gate mechanisms for the non-trafi'ic gates 6 and 7 will not become deenergized due to the fact that three other branches of the energizing circuit for the non-trafiic gate mechanisms will remain closed. These circuit branches include front contact of relay TZR in one branch, front contact c of relay ITR in another branch and front contact b of relay TPR in a third branch. Accordingly, if relay TZZR should become inoperative in a release condition, the non-trafi'ic gates will commence moving to their horizontal position at the same time as the traflic gates commence moving to their horizontal position, that is, when relay TZR releases. 7

As was pointed out earlier, although we have shown our highway crossing apparatus in conjunction with a single direction track, by routine application of a combination of track relays for track sections IT and 2T in conjunction with associated stick relays, the circuit arrangement can be made to operate for two-direction run ning. It should also be clear that our invention is not restricted to conventional direct current neutral track circuits but will operate just as well with polar, alternating current or coded track circuits.

Although we have herein shown and described only two forms of apparatus embodying our invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination with a railway track section intersected by a highway, said track section being provided with a track circuit including a track relay, said intersection being provided with a first set of crossing gates guarding the approach to the intersection and a second set of crossing gates for guarding the exits from said intersection; apparatus for controlling said crossing gates comprising a first series of cascade connected relays includ ing a first relay having a slow-release characteristic and a last relay having a slow-release, slow-pickup characteristic; circuit means for energizing said first relay of said first series closed when the track relay is energized, circuit means for energizing said last relay of said first series closed when said track relay is energized, circuit means for energizing the gate mechanisms of said first set of crossing gates closed when said last relay of said first series is picked up, a second series of cascade connected relays having slow-release characteristics, circuit means for energizing the first relay of said second series closed when said last relay of said first series is picked up, circuit means for energizing the last relay of said second series controlled jointly by the track relay and said last relay of said first series of relays, and circuit means for energizing the gate mechanisms of said second set of 8 crossing gates controlled jointly by said second series of relays, said last relay of said first series and the track relay.

2. In combination with a railway track section intersected by a highway, said track section being provided with a track'circuit including a track relay, said intersection being provided with a first set of crossing gates guarding the approach to the intersection and a second set of crossing gates for guarding the exits from said intersection, a highway crossing signal adjacent said intersection; a first series of cascade connected relays including a first relay having a slow-release characteristic and a last relay having a slow-release, slow-pickup characteristic; circuit means for energizing said first relay of said first series closed when said track relay is energized, circuit means for energizing the gate mechanisms of said first set of crossing'gates closed when said last relay of said first series is picked up, a second series of cascade connected relays having slow-release characteristics, circuit means for energizing the first relay of said second series closed when said last relay of said first series is picked up, circuit means for energizing the last relay of said second series controlled jointly by said track relay and said last relay of said first series of relays, circuit means for energizing the gate mechanisms of said second set of crossing gates controlled jointly by said second series of relays, said last relay of said first series and said track relay, and circuit means for controlling the highway crossing signal closed when said track relay is energized and the next to the last relay of said second series of relays is picked up.

3. In combination with a railway track section intersected by a highway, said track section being provided with a track circuit including a track relay, a first set of crossing gates for guarding the approaches to said intersection, a second set of crossing gates for guarding the exits from said intersection, a highway crossing signal adjacent said intersection; a first series of cascade connected relays including a first relay having a slow-release characteristic and a last relay having a slow-release, slowpickup characteristic; a circuit for energizing said first relay of said first series closed when said track relay is energized, a circuit for energizing the gate mechanisms of said first set of gates in multiple closed when the last relay of said first series is picked up, a second series of cascade connected relays having slow-release characteristics, a circuit for energizing the first relay of said second series closed when said last relay of said first series is picked up, a circuit for energizing the last relay of said second series closed when said track relay is energized, another circuit for energizing said last relay of said second series closed when said last relay of said first series is picked up, a circuit for energizing in multiple the gate mechanisms for said second set of gates comprising a plurality of multiple branches, one of said branches being closed when said track relay is energized, another of said branches being closed when said last relay of said first series is picked up, and a branch being closed when each relay of said second series is picked up, and a circuit for energizing said highway crossing signal closed when said track relay is energized, said last relay of said first series is picked up and the next to last relay of said second series is picked up.

4. In combination with a railway track section intersected by a highway, said track circuit being provided with a track circuit including a track relay, a first set of crossing gates for guarding the approaches to said intersection, a second set of crossing gates for guarding the exits from said intersection, a highway crossing signal adjacent said intersection; a first series of cascade connected relays including a first relay having a slow-release characteristic and a last relay having a slow-release, slow-pickup characteristic; a circuit for energizing said first relay of said first series including a front contact of said track relay, a circuit for energizing in multiple the mechanisms of said first set of ga'tes including a front contact of thelast relay of said first serie s, a secondseries of cascade connected relays having a slow-release characteristic, a circuit rorefiergizing the first rela'y of said second series including a'front contact of said last relay of said first series, a circuit for energizing the last relay of said second series including a front contact of said track relay, another circuit for energizing the last relay of said second series including a front contact of said last relay of said first series, a circuit for energizing in multiple the gate mechanisms of said second set of crossing gates comprising a plurality of multiple branches, one of said branches including a front contact of said track relay, a second of said branches including a front contact of said last relay of said first series, and other of said branches each including a front contact of one of the relays from said second series, a control relay, a circuit for energizing said control relay including a front contact of said track relay and a front contact of said last relay of said first series and a front contact of the last relay of said second series, and a circuit for energizing said highway crossing signal including a back contact of said control relay.

5. In combination with a railway track section intersected by a highway, said track section being provided with a track circuit including a track relay, said intersection being provided with a first set of crossing gates for guarding the entrances to said intersection, said intersection further being provided with a second set of crossing gates for guarding the exits from said intersection; a series of cascade connected relays including a first relay having a slow-release characteristic and a last relay having a slow-release, slow-pickup characteristic; circuit means for energizing said first relay of said series when said track relay is energized, circuit means for energizing the mechanisms of said first set of gates closed when said last relay of said series is picked up, another relay, a capacitor across the winding of said other relay to provide it with a slow-release characteristic, a first circuit means for energizing said other relay closed when said track relay is energized, a second circuit means for energizing said other relay closed when said last relay of said series of relays is picked up, and circuit means for energizing said gate mechanisms of said second set of gates controlled jointly by said track relay and said other relay.

6. In combination with a railway track section intersected by a highway, said track section being provided with a track circuit including a track relay, a first set of crossing gates for guarding the entrances to said intersection, a second set of crossing gates for guarding the exits from the intersection, a highway crossing signal adjacent said intersection; a series of cascade connected relays including a first relay having a slow-release characteristic and a last relay having a slow-release, slow-pickup characteristic; a circuit for energizing said first relay of said series including a front contact of said track relay, a circuit for energizing the mechanisms of said first set of crossing gates including a front contact of said last relay of said series, another relay, a capacitor connected across the winding of said other relay to provide it with a slow-release characteristic, a first circuit for energizing said other relay including a front contact of said track relay, a second circuit for energizing said other relay including a front contact of said last relay of said series, a first circuit for energizing the mechanisms of said second set of gates in multiple including a front contact of said other relay, a second circuit for energizing in multiple the mechanisms of said second set of gates including a front contact of said last relay of said series of relays, a third circuit for energizing the mechanisms of said second set of gates in multiple including a front contact of said track relay, a control relay, a fourth circuit for energizing the mechanisms of said second set 0 of gates in multiple including a front contact ofth'efirst relay of said series of relays, acircuit for energizing said control relay including a front contact of said track relay and a frontco'ntact of-said last relay of said series of relays and a front contact of said other relay, and a circuit for energizing said highway crossing signal including aback contact of said control relay.

7. In combination with a railway track section intersected by a highway; said intersection being provided with a first set of crossing gates guarding the approach to the intersection, a second set of crossing gates guarding the exits of said intersection, and signals for indicating to those on the highway the approach of a train on said railway track section; a control for said signal, means for actuating said control to start operation of said signals in response to the presence of a train in said railway track section, means for causing the first set of crossing gates to move toward a traflic obstructing position at an interval after said signals begin to operate, means for causing the second set of crossing gates to move toward a traffic obstructing position at an interval after said trafiic gates have begun to move, means for causing the second set of crossing gates to move out of traffic obstructing position in response to a train moving out of said railway track section, means for causing the first set of crossing gates to move out of traific obstructing position at an interval after the second set of crossing gates have begun to move out of their traflic obstructing position and means for affecting said control to cause cessation of operation of said signals at an interval after the first set of crossing gates have begun to move out of their traffic obstructing position.

8. In combination with a railway track section intersected by a highway, said track section being provided with a track circuit including a track relay, and said intersection being provided with a first set of crossing gates guarding the approaches to the intersection and a second set of crossing gates guarding the exits from the intersection; a first relay having a slow-release, slowpickup characteristic; circuit means for energizing said first relay closed when said track relay is energized, a second relay having a slow-release characteristic, first circuit means for energizing said second relay closed when said track relay is energized, second circuit means for energizing said second relay closed when said first relay is energized, circuit means for energizing the gate mechanisms of said first set of crossing gates closed when said first relay is energized; and circuit means for energizing the gate mechanisms of said second set of crossing gates controlled by front contacts of said first relay, said second relay and said track relay in multiple, whereby said first set of gates is lowered before said second set of gates is lowered.

9. In combination with a railway track section intersected by a highway, said track section being provided with a track circuit including a track relay, and said intersection being provided with a first set of crossing gates for guarding the approaches to the intersection and a second set of crossing gates for guarding the exits from said intersection; a series of cascade connected relays including a first relay having a slow-release, slowpickup characteristic and a second relay having a slowrelease characteristic; circuit means for energizing said second relay closed when said track relay is energized, circuit means for energizing said first relay closed when said second relay is energized, a third relay having a slow-release characteristic, first circuit means for energizing said third relay closed when said track relay is energized, second circuit means for energizing said third relay closed when said first relay is energized, circuit means for energizing the gate mechanisms of said first set of crossing gates closed when said first relay is energized; and circuit means for energizing the gate mechanisms of said second set of crossing gates controlled by front contacts of said first relay, said third relay and said track relay in multiple, whefeby the first set of gates is lowered before the second set of gates is lowered.

I References Cited in the file of this pzitent UNITED STATES PATENTS Parkinson Feb. 11, 1936 12 Reichar d Nov. 8, 1938 Mickley, Dec. 5, 1939 Evans et al. .J July 23,1940 Thompson Feb. 8, 1949 Staples Sept. 29, 1953

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