US2071961A - Apparatus for the control of highway crossing signals - Google Patents

Description

H. S. YOUNG Febfzs, 1937.

APPARATUS FOR THE CONTR OL'OF HIGHWAY CROSSING SIGNALS Filed Aug. 27; 1936 a Sheets-Sheet 1 IN VENTOR QWMSMW B I Young. BY V H15 YATTQRNEY H. S. YOUNG Feb. 23, 1937.

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS.

Sheets-Sheet 2 Filed Aug. 27, 1956 INVENTOR v Henr 'ouny.

HIS ATTORNEY APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SI GNALS Feb. 23, 1937.

H. s. YOUNG Filed Aug. 27, 1936 s Sheets-Sheet s .INVENTOR .Ybun

BY I

HIS 'ATTOR/NEY Patented Feb. 23, 1937 UNITED STATES APPARATUS FOR THE CONTROL OF'HIGH- WAY CROSSING SIGNALS Henry Young, Wilkinsburg, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application August 27, 1936, Serial No. 98,216

11 Claims.- (01. 246126) My invention relates to apparatus controlled by a train approaching a highway crossing for governing the operation of a highway crossing signal.

A feature of my invention is the provision of novel and improved apparatus controlled by a train approaching a highway crossing for preventing a continued operation of a highway crossing signal in the event the train should stop within the control section, and for restarting the opera- ;a tion of the signal when the train resumes its movement. Other features and advantages of my invention will appear as the specification progresses.

I will describe several forms of apparatus em- 1; bodying my invention, and will then point out the novel features thereof in claims.

Apparatus and circuits controlled by a train for preventing a continued operation of a highway crossing signal in the event a train should stop 3) within the'control section for the signal and for restarti'ngthe operation when the train resumes its movement are disclosed and claimed in the copending application for United States Letters Patent, Serial No. 58,716, filed January 11, 1936,

by James J. Vanhorn for Apparatus forthe control of highway crossing signals, and of which application my present application is an improvement.

In the accompanying drawings, Fig. l is 2. dia- 39 grammatic view of one form of apparatus embodying my invention, and arranged for a track on which trafiic moves in one direction only. Fig. 2 is a diagrammatic view of another form of apparatus for a track on which trains normally move in one direction only, and which apparatus also embodies the invention. Fig. 3 is a dia grammatic view of a modification of the apparatus of Fig. 1, and which is applied to a track where trains are ordinarily required to stop only at cerio tain points. Fig. 4 is a diagrammatic view of apparatus for a railway track on whichtrains normally move in either direction, and which apparatus also embodies the invention. Figs. 5 and 6 are diagrammatic views of train actuated de- 45 vices for producing periodic interruptions of a control circuit only when a train is moving, and

which devices may be used in the apparatus of Figs. 1, 2, 3, and 4. Figs. 7 and 7a. are diagrammatic views of a track instrument effective to de- 50 tect moving and stationary, conditions of a train, and which track instrument may be used as the train actuated device in the apparatus of Figs. 1, 2, 3, and 4.

In each of the several views, like reference characters designate similar par- Referring first to Fig. 1, the reference characters la and I b designate the track rails of a stretch of railway over which trains normally move in the direction indicated by an arrow, and which rails are intersected by a highway H. A 5 highway crossing signal S is located at the intersection. This signal S may be any one of several types of highway crossing signals, and, as here shown, is an audible signal in the form of an electric bell. The operation of the signal S is 10 relay TER, the arrangement being such that when relay SR is released andits back contact 2 is closed, or when the relay TER is released and its back contact 3 is closed, current is supplied to the signal S over a simple operating circuit including contacts 2 and 3 in parallel and the bell sounds a warning. The track rails la and lb may be included in. a track circuit for a wayside signal system, but they need not be, since the apparatus of Fig. 1 is operative independent of any wayside signal system.

' A series of train actuated devices Al, A2, A3, A4, and A5 is provided, the individual devices being operatively associated with the track rails at selected points on the side of the highway from which trains approach the intersection when they are moving in the normal direction of trafiic. These train actuated devices may take different forms, and are shown conventionally in Fig. 1 for the sake of simplicity. One form for the train actuated devices is the track instrument disclosed diagrammatically inFigs. 7 and 7a. This track instrument comprises a weight member 10 attached to one end of a flexible member H which is mounted on the track rail at 12 in any convenient manner. A surface of the weight member 10 is provided with a depression 13. Under normal conditions, that is, when flexible member II and weight member 10 are not vibrated, the point of a plunger 14 rests in the depression 13. The plunger 14 is attached to a contact finger 15 which is fixed at 16. A second contact finger H is fixed at 80 and is normally in engagement with contact finger 15 to complete a circuit connection therethroug A stop member 18 limits the movement of contact finger 11. When the track rail is vibrated by the wheels of a train passing the point at which the flexible member 15 is attached to the rail, the flexible member and weight are vibrated but the inertia of the weight makes itslow to follow the vibrations so that'the plunger 14 is forced out of the depression 13 and the contact finger 75 is forced to the right as viewed in Fig. 7a to break the engagement with contact finger vTi. Thus a train wheel moving over the rail at the point at which the track instrument is attached thereto causes the contact 15-11 to open at least momentarily. When no train is present or when a train is standing and the rail is not vibrated, contact 15Tl is closed. It will be understood, of course, that the parts of the track instrument are properly insulated from each other and are also housed againstweather and other outside interferences. 1

Another form of track instruments that may be used as the train actuated device is that disclosed and claimed in a copending United States application for Letters Patent,'Serial No. 54,500, filed December 14, 1935, by H. G. Witmer, for Circuit controlling instruments.

The essential thing regarding the train actuated devices as far as the present application is concerned is that each device includes a circuit controlling element or contact which assumes an open or non-conducting condition only when a train is moving in the vicinity of the device, but when no'train is present or when a train is standing, the circuit controlling element assumes a closed condition in which current readily passes therethrough. For example, the contact 4 of device AI is normally closed and assumes an open position when a train is moving in the vicinity of the device Al. The train actuated devices of the series are placed close enough together so that a train moving at an appreciable speed passes from the point where it actuates the circuit controlling element of one device to a point where it actuates the circuit controlling element of the next device in something less than a predetermined period of time W ch period I shall assume for the purpose of illustration to be 5 seconds. The relationship of this predetermined period of time with the rest of the apparatus will be referred to hereinafter. While the series of train actuated devices of Fig. 1 contain but fiveindi vidual devices, it is to be understood that the series may comprise any desired number. The first device Al encounteredby' a train approaching the crossing is located from the highway a distance sufficient so that a desired minimum warning period of the highway crossing signal prior to the arrival of the train at the crossing when the train is moving at the maximum speed is assured. The last device A5 of the series is preferably located adjacent the highway crossing. It is to be pointed out that the track instruments here contemplated for use as train actuated devices are of a type which is not effectively influenced by vibrations transverse to the track rail such as might be caused by a train moving on an adjacent track.

The circuit controlling elements 4, 5, 6, I, and 8 of the train actuated devices Al, A2, A3, A4, and A5, respectively, are connected in series in a circuit for the control relay SR, the circuit normally including front contact 9 of the relay as will be readily understood by an inspection of Fig. 1. The slow acting relay 'IER associated with the control relay SR is here shown as a slow pickup relay. The relay TER is so proportioned and adjusted that its contact arm ID is moved and breaks engagement with back contact 3only after the winding of the relayvhas been energized a predetermined period such as 5 seconds, but that upon deenergization of the winding of the relay, the contact arm l immediately drops from what ever position it has been advanced to the position where it engages the back-contact 3. Relay TER is provided with a check contact ll-|2, the contact finger H of which is operatively associated with contact arm I 0, as indicated by a dotted line in the drawings. The arrangement is such that contact finger H engages the stationary contact finger I2 only when the relay is deenergized and its mechanism is fully released. The check contact ||--I2 is interposed in the control circuit of relay SR in parallel with front contact 9, and hence relay SR once deenergized and its front contact 9 opened, it is reenergized only if relay TER. is released and check contact ll-IZ is closed. Relay TER is energized by a simple circuit including front contact l3 of control relay SR.

When a train approaching the highway reaches the location of device Al, the contact 4 is actuated at least momentarily to its open position to open the stick circuit of relay SR and relay SR is deenergized and releases to close back contact 2 interposed in the operating circuit of signal S, and signal S is set into operation. The release of relay SR opens front contact l3 interposed in the energizing circuit of relay TER, and this latter relay is released to close back contact 3 and complete the second parallel path of the signal operating circuit. Check contact Il-IZ is closed also when relay TER is deenergized and its mechanism is fully released. In the event the train continues uninterruptedly toward the highway crossing, the circuit of relay SR is successively opened at the circuit controlling elements of the successive train actuated devices, and operation of the signal S is continued uninterruptedly until the rear of the train passes the location of the last device A5 which is located close to the crossing, since the devices are so spaced that relay- TER is not energized long enough to open its back contact 3, When the rear of the train passes to the right of device A5 and contact 8 is closed, relay SR is energized over the circuit including the contacts of the several train actuated devices and the check contact ll-l2, .and, upon picking up, closes its stick circuit at front contact 9. One path of the signal operating circuit is now open at back contact 2 of relay SR, but operation of the signal is continued by means of the path including back contact 3 of relay 'I'ER. With relay SR picked up the relay TER is energized and picks up to open back contact 3 at the expiration of its predetermined pick-up period and which period I have assumed to be 5 seconds. Thus, operation of the signal S is stopped substantially 5 seconds subsequent to the rear of the train passing the device A5. As set forth hereinbefore, the train actuated devices of the series are placed close enough together that a train moving at an appreciable speed passes from one device to the next in something less than 5 seconds. It follows that for all trains that do not stop along the section equipped with the train actuated devices, the signal is operated continuously from the time the head end of the train encounters the first device Al until substantially 5 seconds subsequent to the rear of the train passing the last device A5.

In the event a train should stop at any point along the control section, the circuit controlling elements 4 to 8, inclusive, all assume the closed condition in which they pass current and relay SR is picked up and relay TER is energized with the result that operation of signal S ceases substantially 5 seconds after the train stops. As soon as the train resumes its movement, the circuit controlling element of thedevlce in the vicinity of the train assumes the open or non-con- C of the current source.

ducting condition and; relays SR and TER are 1 ing signal ceases at the expiration of a predetermined period, and operation of the signal is restarted at once when thetrain again resumes its movement.

In Fig. 2, traffic normally moves over the track,

rails Ia and lb in the direction indicated by an arrow, the rails are intersected by a highway H at which a signal S is located, and .a series of train actuated devices is associated with the track rails the same as in Fig. 1. The control relay SR of Fig. 2- is likewise retained energized over a stick circuit that includes its own frontcontact 9 and the circuit controlling elements 4 to 8, inclusive, of the train actuated devices the same as in Fig. 1. In this form of the invention, the slow acting relay is a thermal relay TH having associated therewith two relays TPR and TSR, Normally, that is, when no train cupies the control section, the relay SR is energized over the stick circuit referred to above, relay TSR is energized over a stick circuit that includes its own front contact I5 andfront contact I4 of relay SR, and relay TPR is energized over a simple circuit including check contact I5 of thermal relay TH.

When the head end of a train approaching the highway crossing encounters the train actuated devices AI of Fig. 2, contact 4 assumes its open condition and control relay SR is released to close at its back contact I1 one path in the operating circuit for the signal S, and operation of the signal is initiated; Relay SR, upon releasing, opens front'contact I4 interposed in the stick circuit for relay TSR and this latter relay is deenergized and releases to close at its back contact I8 a second branch path of the signal operating circuit. If this train continues without stopping, one or more of the circuit controlling elements of the train actuated devices are actuated at intervals less than the operating time of relay TH and operation of the signal S is continued without interruption until the rear of the train passes beyond the last device A5. When contact 8 of device A5 is closed, relaySR is picked up over a circuit that may be traced from the B terminal of the current source through the circuit controlling elements 4 to 8 of the train actuated devices, winding of relay SR, back contact 20 of relay TSR, front contact 2I of relay TPR, and to the opposite terminal With relay SR picked up and relay TSR down, current is supplied to the heater element I9 of thermal relay TH, the circuit including front contact I4 of relay SR, and back contact 22 of relay TSR. Check contact I6 of relay TH is at once opened subsequent to the heater element I9 being supplied with current, and relay TPR is released to open at its front contact 2| the pick-upcircuit for relay SR and to close at its back contact 23 a third branch path in the signal operating circuit.

Subsequent to the opening of check contact I6 and release of the relay TPR, control relay SR is retained energized over its stick circuit including front contact 9, which contact when closed completes, in effect, a shunt path around the check contact I6. Contact 24 of thermal relay TH is closed at the expiration of a predetermined period, say, for example, 5 seconds. and completes a pick-up circuit for relay TSR which circuit includes front contact I4' of relay SR, contact 24 of relay TH, and winding of relay TSR. Relay TSR at once picks up and is then retained energized over its front contact I5. The picking up of relay TSR to open back contact 22 interposed in the circuit for the heater element I9 causes relay 'IH to cool and reclose'check contact It so that relay TPR is reenergized. With all three relays SR, TSR, and TPR restored to their normal energized conditions, all three branch paths of the signal operating circuit are opened and operation of the signal is stopped. It follows that when a train continues through the control section without stopping, the signal S is operated without interruption from the time the head end of the train encounters the first device AI until the expiration of the operating time of the thermal relay TH, subsequent to the rear of the train passing to the right of the last device A5.

InIcase a train stops along the control section so that the contacts of the train actuated devices all assume the closed position, the relay SR is picked up and thermal relay TH is operated in the manner set forth above with the result that operation of the signal is discontinued at the end of the operating time of relay TH. A train having stopped and then again resuming its movement causes the circuit controlling element of the device in the vicinity of the train to assume its open position with the result that the relay SR is deenergized and operation of the signal is restarted.

In Fig. 3, the normal direction of trafiic is that indicated by the arrow and'the track rails to the left of the highway H are divided into two insulated track sections IT and 2T, the section 2T being adjacent the highway. These sections IT and 2T are each provided with the usual track circuit, which circuits include the track relays ITR and 2TR, respectively. A series of train actuated devices A6, A1, and A8 is provided for the section IT, the devices being spaced at selected points along the section. The initial device A6 of the series is preferably located not far from the entrance of the section, and the final device A8 is preferably located not far from the exit end of the section. Although only three devices are disclosed, it will be understood that the series may include any number and will include a sufl'icient number so that a train moving at a low speed will pass from one device to the next in something less than a predetermined period of time which may be 5 seconds. In practicing the invention, the section IT would be extended to include points at which trains may ordinarily be required to stop, such as, for example, a passenger station or siding. The combined length of the two track sections IT and 2T is sufficient to provide a desired minimum warning period of the highway crossing signal prior to the arrival of a train at the crossing when the train is travelling at the maximum spee for all trains.

Signal S 'of Fig. 3 is governed over the back contact 25 of a relay XR'. Relay XR, in turn, is normally energized over a circuit including front contact 26 of track relay ITR and front contact 21 of track relay 2TR. Relay XR is en ergized at times over an alternative circuit which may be traced from the B terminal of the current source over front contact 30 of control relay SR, iront contact 29 of the associated slow pick-up relay 'I'ER, back contact 28 of track de lay I TR, front contact 21 of relay 2TR, winding of relayXR and' to the C terminal of the current source.

A train approaching the highway and entering track section 1 T shunts track relay lTR and that relay upon releasing opens the circuit'for' relay XR which in turn'releases to close the op---- erating circuit for the signal S', and the signal establishes a warning indication. Relay 1 TH upon releasing also closes at its back contact 3| an energizing circuit for control relay SR, and that relay is at once picked up. This energizing circuit includes battery terminal B, circuit controlling elements 32, 33, and 19 of the train ac tuated devices A6, A1, and A8,-respective1y, back contact 3| of relay ITR, winding of relay SR", check contact ll-l2 of relay TER, and to the opposite terminal C of the currentsource. Relay SR on picking up closesat its front contact-34 a shunt path around the check contact lI-l2 and completes at its front contact an energizing circuit for the slow pick-up relay TER- which relay is set into operation to close its contact 29 at the end of the predetermined pick-up period which preferably would be 5 seconds to agree with the spacing of the actuateddevices referred to hereinbefora If the train advances at an appreciable speed, it reaches the first device A5 in. less than the pick-up period of relay TER with the result that the contact 32 of device A6 is caused to assume its open position. andrelays SR and TER are deenergized. In the event the train proceeds without stopping through thesection IT, the relay SR is retained deenergized or at least is deener gized at intervals less than the pick-up period of relay TER and operation of the signal is continued without interruption. When the train enters the section 2T and shunts track relay 2TR, the relay XR is retained deenergized by virtue of front contact 21 of relay ZTR being open, and operation of the signal is continuedshould stop while advancing through section IT,

the energizing circuit for relay SR is at once closed and that relay is picked up to initiate operation of the slow pick-up relay TER. With both relays SR and TERpicked up, the alternative circuit for relay XR is completed with the result relay XR is picked up and the operation of the signal is stopped. When the train resumes its movement, the train actuated device in the vicinity of the train is influenced to cause the relay SR to be deenergized and operation of the signal is again started.

In Fig. 4, a stretch of railway track over which trafiic normally moves in either direction is intersected by a highway H adjacent which a highway crossing signal S is located. This stretch of railway track is formed into two insulated track sections 3T and 4T, the junction of the two sections being located at the highway crossing. At the junction of sections 3T and 4T, the arrangement is such that the insulated rail joint 35 is placed in one rail to the left of the highway'an'd the other insulated rail joint 36 is placed in the other rail to the right of the highway as will be readily understood by an inspection of Fig. 4; The track section 3T is provided with a track circuit which includes the left-hand magnet 31 of an interlocking relay IR, and the track section 4T is provided with a track circuit which includes the right-hand magnet 38 of the relay IR. A series of train actuated devices A9, AID, and AH- isassocla-ted wit-hi sectib'ir and a second series of-"-i srai1ractuated; devices A42, A13, and A14 is as'soelated: with the" track section 4 -4T'. Although only" three idevices are shown for each of these series;-it will beunderstood that each series in-' clud'esa sumcient number of devices that a train movingat an appreci'abl'e speed will'advance from one device to the next in something less'than a predetermined period of' timewh'ich may be 5 seconds as' ass'um'ed herei'nbeforel An individual train actuateddevlceAiiis associated with the; track railsadjacent the intersection, that-is, it is positioned at some; point between the insulated rail joints" 35 and 35 but in a position where highway trailic will' not effectively influence the device. In this connection, it isto be recalled that track instruments of the type h'ere contemplated are not readily responsive to vibrations transverse to the track rail". A control relay SR and an associ'ated slow pick-up'relayTER are provided for the apparatus of Fig. 4.

In describing" the operation of the apparatus oi'Fig'. 41 I'shall first consider the case of a train approa ching'the highway-crossing from the left.

The train upon entering'section 3T shunts mag net 31 of relay IR and that magnet is released to close its-- full down contacts; and 41. With back contact 4| closed, the operating circuit for signal S is completed, and operation of the signal is'initiated. The operating circuit for signal S includes the back contact of relay SR and the back contact 43- of relay TER- in parallel, and the back contact 41 of magnet 31- or' back contact 56 ofmagnet38 depending'upon which of these magnets is released first. The closing of contact 46' of'magnet 31 completes a circuit for control relay SR; andwhich circuit starts from battery terminal B at the left hand end of Fig; 4' and extends through thecircuit controlling elements 44, 45, and 4B of the train actuated devices A9, All); and A| |',.respectively,' back contact 40, wire 41; front contact 48 of magnet 38, wire 49, circuit controlling element 5|! of device A15, wire 51, winding of relay SR, check contact ll-l2 of relay TER, and to terminal C. Relay SR on picking up completes at its front contact 52 a shunt path around check contact Hl2, and

completes at front contact 33 an energizing cirsignal" is continued over the branch path including back contact 43 of relay TER. In the event the trainjcontinues its movement, it causes the contact 44 of device A9 to open the circuit for relay and stop the operation of relay TER prior to the interval back contact-i 43 is opened, and hence operation of the signal is continued without interruption: from the time the train enters section 3T until after the rear of the train passes to the rightof the highway since the circuit for relay SR is retained open'at the successive train actuated devices; When the head end of the train passes to the right of the insulated raii joint 36 the magnet 38 is deenergized but its back contacts 54, 55, and 56 areheld open andits front contact- 48 is held closed due to the interlocking featureof the relay.

Itis be noted that when the rear of th train is on the crossing the track circuit of section 3'T'is still shunted and magnet 31 is retained deenergized. This shunt path may be traced from the upper rail at the left ofinsulated rail joint 35 over wire 51, back contact 33, wire 58 to 1 stop at any point along the section 3T, then relay SR is energized and the slow pick-up relay TER is operated with the result that operation of the signal S is discontinued at the expiration of the pick-up period of relay TER. 1 As soon as the train Y starts up again, the circuit for the relay SR is opened at the device in the vicinity of the train and operation of the signal is reestablished.

It is apparent that the operation of the apparatus of Fig. i in response to a train approaching 1 the highway from the right through track section d'I' is similar to that described in connection with a train approaching the highway crossing from the left, and it is thought that it need not be repeated.

Fig. 5 discloses apparatus for a train actuated device that may be used to interrupt the circuit for the control relay SR when a train is moving and to close the circuit when the train stops. The apparatus consists of a track circuit comprising a short insulated rail 55, a track battery 66 connected between rail 59 and the opposite rail 6!. and the Winding of a relay 62 connected between the. rails 59 and iii. The insulated rail 59 is shorter than the distance between the two trucks of the usual railway car. It follows that relay 62 is normally energized, is deenergized and released in response to the first truck wheel spanning the rails 59 and. 6!, and is momentarily picked. upduring the interval between the last wheeler the first truck of the car passing on" rail 59 andjthe entrance of the leading wheel of the second truck passing onto rail 59. The control circuit for relay SR includes a front contact 63 and a back contact 66 of relay, 52 in parallel. Consequently, as long as relay 62 is steadily energized, or is continuously deenergized, the circuit for relay SR is closed,,but a train moving over the rail 59 causes the circuit to be periodically interrupted. To check the normal position of relay 52 the front contact 55 may be interposed in a wayside signal control circuit.

In Fig. 6, another possible arrangement for detecting movement of a train is disclosed. Here 'a track instrument Al 6 governs over its circuit controlling element 66 a relay M, the front contact 68 and back contact 69 of which relay are interposed in parallel in the control circuit for relayv Although I have described only certain forms of apparatus embodying my invention, it is 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 my invention.

Having thus described my invention,.what I claim is:

1. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a control relay, a slow acting relay having a contact arm which is actuated in a predetermined interval, a series of train actuated devices spaced along the track rails for at least a portion of the stretch, said devices each including a circuit controlling element which is actuated to an open condition only when a train is moving in the vicinity of the device,

circuit means-for energizing the control relay and serially including the elements of the devices of the series,*an operating circuit for the slow acting relay including a front contact of the control relay, and other circuit means for governing the operation of the signal and including said contact arm of the slow acting relay whereby operation of the signal is effected when a train moves uninterruptedly through the stretch of railway and is stopped at the end of said predetermined'interval when the train stops along the stretch. I

2. Inco-mbination', a stretch of railway track intersected by a highway, a highway crossing signal located'at the intersection, a slow acting relay having a contact arm which is actuated in a predetermined time interval,'a series of trainv actuated devices spaced along the track rails for at least a portion of the stretch, said devices each including a circuit controlling element which is actuated to an open condition only when a train is moving in the vicinity of the device, and said devices'spaced sufficiently close together that a train moving at a given low speed will pass from one device to the next in substantially said predetermined time interval, circuit means for operating the slow acting relay and serially including the elements of said devices, and means for governing the operation of the signal including the contact arm of the relay.

3. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a slow pick-up relay having a predetermined pick-up period, a

control relay, a series of train actuated devices :5.

spaced along the track rails for at least a portion of the stretch, said devices each including a circuit controlling contact which is actuated to an open position only when a train is moving in the vicinity of the device, and said devices spaced suiiiciently close together that a train moving at an appreciable speed passes from one device to the next in less than said predetermined'pick-up period of the slow pick up relay, a control circuit for the control relay including the contacts of said devices in series, means including a front contact of the control relay to energize the slow pick-up relay, operating'means governed by the control relay effective to operate the signal when the control relay'is deenergized, and other operating means governed by the slow pick-up relay efiective to operate" the signal when the slow pick-up relay is deenergized.

4. In combination, a stretch of railway track intersected by a highway; a highway crossing signal located at the intersection, a slow pick-up relay having a predetermined pick-up period, a series of train actuated devices spaced along the track rails of the stretch with the nearest device adjacent the intersection and the most remote device a predetermined-distance from the intersection, said devices spaced sufliciently close together that atrain moving at a given low speed will pass from one device to the next in substantially said predetermined period, said devices each including-a circuit controlling element which is actuated to a non-conducting condition only when a train is moving in the vicinity of the device, circuit means to energize said'slow pick-up relay and serially including the elements of said devices, and means for governing the operation of the signal including a contact of said relay.

5. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a control relay, a

iii)

slow pick-up relay having a predetermined pickup period, a series of train actuated devices spaced along the track rails of the stretch with the nearest device adjacent the intersection and the most remote device a predetermined distance from the intersection, said devices spaced sufficiently close together that a train moving at a given low speed will pass from one device to the next in substantially said predetermined period, said devices each including a circuit controlling element which is actuated to an open condition only when a train is moving in the vicinity of the device, a control circuit for the control relay serially including the elements of the devices, a circuit for the slow pick-up relay including a front contact of the control relay, and circuit means for governing the signal controlled jointly by the control and slow pick-up relays.

6. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a control relay, a slow pick-up relay having a predetermined pick-up period and including a check contact, a series of track instruments spaced along the stretch with the first instrument a predetermined distance from the intersection and the last instrument adjacent the intersection, said instruments spaced sufliciently close together that a low speed train will move from one instrument to the next in substantially said predetermined period, said instruments each including a contact which is opened at least momentarily by the vibration created in a track rail by a train moving past the instrument, circuit means for energizing said control relay including the contacts of said instruments and said check contact, means including a front contact of the control relay to shunt around the check contact, an operating circuit for the slow pick-up relay including a front contact of the control relay, and means for operating the signal including a contact of the slow pickup relay.

7. In combination, a stretch of railway track over which traflic moves in either direction and which is intersected by a highway, a highway crossing signal at the intersection, a slow pickup relay having a predetermined pick-up period, two series of train actuated devices one on each side of the crossing, said devices each including a circuit controlling element which assumes an open condition only when a train is moving in the vicinity of the device, the devices of each series spaced sufliciently close together that a train moving at an appreciable speed passes from one device to the next in less than said predetermined pick-up period, two circuit means each effective to energize said relay and one serially including the circuit elements of the devices of one series and the other serially including the circuit elements of the devices of the other series, means controlled by a train to place the relay under the control of the circuit means associated with the direction in which the train approaches the crossing, and an operating circuit controlled by a train approaching the crossing in either direction to operate the signal and including a back contact of said relay.

8. In combination, a stretch of railway track over which traffic moves in either direction and which is intersected by a highway, a highway crossing signal at the intersection, a slow pick up relay having a predetermined pick-up period, two series of train actuated devices one on each side of the crossing, said devices each including a circuit controlling element which assumes an open condition only when a train is moving in the vicinity of the device, the devices of each series spaced sufficiently close together that a train moving at an appreciable speed passes from one device to the next in less than said predetermined pick-up period, two circuit means each eiiective to energize said relay and one serially including the circuit elements of the devices of one series and the other serially including the circuit elements of the devices of the other series, means controlled by a train to place the relay under the control of the circuit means associated with the direction in which the train approaches the crossing, an operating circuit controlled by a train approaching the crossing in either direction to operate the signal and including a back contact of said relay, an individual train actuated device located adjacent the crossing, and means governed by said individual device when actuated by a train to render said two circuit means both ineffective to energize said relay.

9. In combination, a stretch of railway track over which trafiic moves in either direction and which is intersected by a highway, ahighway crossing signal at the intersection, a slow pickup relay having a predetermined pick-up period, two series of train actuated devices one on each side of the crossing, said devices each including a circuit controlling element whichassumes an open condition only when a train is moving in the vicinity of the device, the devices of each series spaced sufficiently close together that a train moving at an appreciable speed passes from one device to the next in less than said predetermined pick-up period, two circuit means each effective to energize said relay and one serially including the circuit elements of the devices of one series and the other serially including the circuit elements of the devices of the other series, means controlled by a train to place the relay under the control of the circuit means associated with the direction in which the train approaches the crossing, an operating circuit controlled by a train approaching the crossing in either direction to operate the signal andincluding a back contact of said relay, and directional means controlled by a train travelling through the stretch operative to render each series of devices ineffective to control the relay when a train recedes from the crossing.

10. In combination, a stretch of railway track over which trafiic moves in either direction and which is intersected by a highway, a highway crossing signal at the intersection, said track formed into two insulated tracks sections one on each side of the intersection and each provided with a track circuit including a magnet of an interlocking relay, two series of train actuated devices one associated with each section, said devices each including a circuit controlling element which assumes an open condition only when a train is moving in the vicinity of the device, and the devices of each series spaced along the associated section sufiiciently close together that a train moving at an appreciable speed passes from one to the next in less than a predetermined period,ia slow pick-up relay having a pickup period equal to said predetermined period, two circuit means each effective to energize the slow pick-up relay and each serially including the circuit elements of the devices of a particular series and a back contact of the interlocking relay magnet associated with the same section as the series, and an operating circuit for the signal including a back contact of the slow pick-up relay in series with a back contact of each of interlocking relay magnets in parallel.

11. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a slow acting relay having a predetermined operating period, means controlled by said relay for at times operating said signal, a series of short insulated track sections spaced apart on one side of the inter- 10 section, said sections each characterized by being shorter than the distance between the two trucks of a railway car, and said sections sufficiently close together that a train moving at an appreciable speed passes from one section to the next in less than said predetermined operating period, a track circuit for each section including a track relay, and circuit means for operating said slow acting relay and including a front and a back contact in parallel of each relay of said sections.

HENRY S. YOUNG.

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