US2993117A - Dragging equipment detector system - Google Patents

Description

United States Patent G 2,993,117 DRAGGENG EQUIPMENT DETECTOR SYSTEM Donald D. Huffman, Penn Hills Township, Allegheny County, Pa., assignor to Westinghouse Air Brake Company, Wilmer-ding, Pa., a corporation of Pennsylvania FiledMar. 21-, 1960, Ser. No. 16,495 6 Claims. (Cl. 246-169) My invention relates to dragging equipment detector systems for railroads, and more particularly to circuits for use in connection with self-restoring dragging equipment detectors.

Self-restoring dragging equipment detectors are often disposed in the track ways of railroads to detect the presence of objects hanging or dragging from vehicles traversing the tracks. Such detectors are biased to a normal or unactuated position and, after actuation thereof from their normal position by hanging or dragging equipment, are restored by their biasing means to said normal position. A signal indication device is provided beyond the location of such a detector and is actuated by the detector to give a suitable indication to the engineman of a train when the detector is actuated by hanging or dragging equipment on the train. Since the detectors are self-restoring, means must be provided at the location of a signal indication device to retain the dragging equipment indication until observed by the engineman, and for the engineman or other personnel to restore the indication device to its normal nonindicating condition after the train is stopped and the necessary repairs made to the hanging or dragging equipment.

When a dragging equipment detector system such as that described is employed in a stretch of single track railway over which trains may at different times travel in either direction, and a single dragging equipment detector is employed for actuating a signal indication device located in each direction beyond the device, means must be provided so that only the indication device for the direction of travel of the train operating the detector is actuated, otherwise both indication devices would be actuated and it would be necessary for a maintainer or other railway employee to travel to the other indication device to restore it to its normal nonindicating condition. It is accordingly the object of my invention to provide, in a dragging equipment detector system of the class outlined, and employed in conjunction with a railway signaling system for a stretch of single track in double direction running territory including means for providing following train movements, means for actuating the indication device for the direction of travel of a train operating the dragging equipment detector, and means for preventing actuation of the indication device for the opposite direction of travel.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

In accomplishing the foregoing objects of my invention, I utilize the directional stick relays, employed for providing following train movements in single track double direction running railway territory, to prevent actuation of the dragging equipment indication device for the opposite direction of traflic from that in which a train actuating a dragging equipment detector is traveling.

I shall describe one form of apparatus embodying my invention and shall then point out the novel features thereof in claims.

In the accompanying drawings, FIGS. 1a and lb when placed side by side with FIG. la at the left and FIG. lb at the right comprise a diagrammatic view illustrating the track plan and the apparatus and circuit arrangement of one system embodying my invention.

Referring to the drawings, there is shown a stretch of 2,993,117 Patented July 18, 1961 "ice railway track provided with a simplified typical three aspect automatic signal circuit arrangement of the type often employed in double direction running single track territory, such as the single track between ends of a siding in centralized trafiic control territory. Incorporated in the signaling system shown are provisions for following train movements controlled by directional stick relays at each signal location, as will be more fully pointed out later in this description. It will be understood by those skilled in the art that in such signaling arrangements as that shown, provisions are made for establishing, maintaining, and changing the direction of t'r'aflic between stations or ends of siding, but these means are not shown in the drawings since they form no part of my present invention.

Referring to the drawings in more detail, there is shown at the upper portion thereof a stretch of railway track extending from west to east, or from left to right as shown on the drawings, between two points designated by the reference characters A and C. This stretch of railway track comprises left-hand and right-hand track sections designated 2T and 3T, respectively separated from each other at a point B, intermediate points A and C, by insulated joints J. The stretch of railway track A==C is also separated by insulated joints J from track sections designated IT and 4T located to the left and right of the stretch, respectively.

Each track section is provided with a track circuit including a source of energy connected across the rails at one end and a track relay connected across the rails at the other end in the manner well known in the art, such that the track relays are energized when no train occupics the respective track section. The sources of track circuit energy for track sections 2T and ST are shown as batteries designated 2TB and 3TB, respectively, and the track relays for track Sections 1T, 2T, 3T and 4T are designated ITR, 2TR, 3TR and 4TR, respectively. For purposes of simplicity, the sources of track circuit energy for track sections IT and 4T are not shown in the drawings, but it will be understood they each may be a battery similar to that shown for track sections 2T and 3T.

An entering signal and a leaving signal for governing train movements into and out of the track stretch A-C at the left-hand end thereof are located adjacent the insulated joints at point A. These leaving and entering signals are designated 1G and 2G, respectively. Similarly an entering signal and a leaving signal designated 36 and 46, respectively, are located adjacent the insulated joints at point C for governing train movements intoand out of the track stretch A-C at the right-hand end thereof. These signals may be of any suitable type and each signal as here shown is of the type commonly known as a color-light signal. Signals 1G, 2G, 3G and 4G are shown in the lower portion of the drawings as each having a green lamp, a yellow lamp, and a red lamp designated GE, YE, and RE, respectively, each lamp designation being prefixed by the number of its respective signal. These lamps when illuminated indicate clear; approach, prepare to stop at next signa; and stop, respectively. Signals 1G and 4G are also each provided with an additional indication lamp designated IDEK and 4DEK, respectively. The purpose of these additional lamps will be pointed out later in this description.

As shown in the upper right-hand portion of FIG. la, there is located in the vicinity of point B in the track stretch A--C a dragging equipment detector of the selfrestoring type and designated DED. The details of this detector form no part of my present invention and, therefore, are not shown in the drawings. However, for the purposes of this description, the detector may be similar to that shown in Letters Patent of the United States No.

2,677,048, issued April 27, 1954, to Robert A. Woods and Herbert L. Bone for a Dragging Equipment Detector, but any other similar detector may be employed with my invention. It is considered sufiicient for the purposes of this description to point out that the detector comprises upstanding detector plates supported on a shaft extending between and beyond the rails and arranged so as to be deflected from their upright position when struck by an object hanging or dragging from a vehicle traversing the rails in either direction. The detector plates are biased to their normal or upright position, and accordingly when they are deflected, they return to their normal or nnactuated position as soon as the dragging object clears the detector. Such detectors are, therefore, termed self-restoring detectors. The shaft which supports the detector plates'is operatively connected with a plurality of contacts which are arranged to be normally closed when the plates are in their unactuated or upright position, and to be opened when the detector plates are deflected or actuated. On FIG. 1a of the drawings two such contacts designated a and b are shown in the conventional manner below the detector and indicated as controlled thereby by the dotted line extending from the detector to the contacts. It will be readily apparent, however, that the detector could be provided with but one such contact, and a repeater relay or relays could be controlled by a circuit over that single contact.

It should be pointed out at this time that a suitable source of control current is provided at each of the locations" A and C, these sources being preferably a battery of proper voltage and capacity. However, for the sake of simplicity these sources are not shown in .the drawings, but the positive and negative terminals of the source at location A are designated B1 and N1, re-

spectively; and the positive and negative terminals of the source at location C are designated B2 and N2, respectively.

Located at the signal locations at points A and C are :a signal control relay and a directional stick relay associated with each of the signals. These signal control and directional stick relays are designated by the reference characters HDR and SR, respectively, each designation being prefixed by the number 1, 2, 3 or 4, indicating the number of the signal with which the relay is associated. There are also located at points A and C dragging equipment detector repeater relays designated lDEDSR and 4DEDSR, respectively, and manually operable circuit controllers 1PB and 4PB, respectively. These con- .trollers are here shown as manually operable push buttons each biased to a first or normal position by a spring indicated by the letter S on an extension of the button and actuable to a second or actuated position, when depressed to close a normally open contact a. The direction of depression of the buttons to close contacts a is indicated by the arrow heads shown below the movable portion of the contacts, and springs S operate to return the buttons to their normal position and open the contacts when the buttons are no longer depressed. Such push buttons are well known in the art.

The aforesaid relays 18R, 28R, 38R, 4SR, lDEDSR and 4DEDSR may be of the well known neutral type each having a plurality of front and back contacts opened and closed, respectively, and closed and opened, respectively, according as the relay is deenergized or energized, respectively.

Relays IHDR, ZHDR, SHDR and 4HDR may be of the conventional retained neutral polarized type as substantially shown, the polarized feature of the relay being indicated by the letter P in the rectangle representing the winding of the relay. Such relays are provided with a polarized armature and a neutral ararnature each controlling one or more contacts. The movable portion of the contacts controlled by the polarized armature of the relays are shown in a vertical line on the drawings and are operated to close with a normal or left-hand contact point when positive and negative energy are supplied to the left-hand and right-hand terminals, respectively, of the control windings of the relays, and to close with a reverse or right-hand contact point when positive and negative energy are supplied to the right-hand and lefthand terminals, respectively, of said control windings. A retained-neutral polarized elay is termed retainedneutral because the neutral armature of such a relay does not release if the polarity of the energy supplied to the control winding of the relay is quickly reversed. That is, the neutral armature of such a relay will remain picked up and the neutral front contacts consequently closed during the period of movement of the relays polar contacts from normal to reverse or reverse to normal upon quick reversal of polarity of the energy supplied to the control winding of the relay. This feature is indicated on the drawings by a downwardly pointing arrowthrough the neutral contacts of the relays, thereby indicating, in the conventional manner, that these are slow to release. Such relays are well known in the art and may, for example, be similar to that shown in Letters Patent of the United States, No. 2,363,038, issued November 21, 1944, to Selden B. Aylsworth for an Electrical Relay.

I will first outline in detail the control circuits for the aforesaid simplified typical automatic signal circuit arrangement and will then outline in detail the control circuits for the apparatus of my invention employed in conjunction with such a signaling arrangement.

Signal control relay 2HDR in FIG. la has a normal control circuit extending from battery terminal B2 in FIG. lb over the front point of contact b of relay 4HDR, front contact b of relay 3TR, conductor 8, front contact b of relay ZTR in FIG. 1a, the left-hand terminal of the winding of relay ZI-I-DR, the right-hand terminal of the winding of relay ZHDR, conductor 7, and over the front point of contact a of relay 4HDR in FIG. lb to battery terminal N2.

Relay ZHDR has a reverse control circuit which extends from battery terminal B2 in FIG. 1b over front contact b of relay 4SR, the back point of contact a of relay 4HDR,

.conductor 7, the right-hand terminal of the winding of relay ZHDR in FIG. la, the left-hand terminal of the winding of relay ZHDR, front contact b of relay ZTR, conductor 8, front contact b of relay 3TR in FIG. lb, the back point of contact b of relay 4HDR, and over front contact 0 of relay 4SR to battery terminal N2. It is thus apparent that relay ZHDR is deenergized when either of the track sections 2T or 3T are occupied, or when relays 4HDR and 4SR are both deenergized. Relay ZHDR is energized by current of normal polarity, that is, current of the polarity to control the polar contacts of the relay to their normal or left-hand position when relay 4HDR is energized as hereinafter discussed; and is energized by current of reverse polarity, that is, current of the polarity to control the polar contacts of the relay to their reverse or right-hand position when relay 4HDR is deenergized and relay 4SR is energized as hereinafter described.

Signal control relay 3HDR in FIG. lb has a normal control circuit which extends from battery terminal B1 in FIG. 1a over the front point of contact a of relay lHDR, front contact a of relay ZTR, conductor 5, front contact a of relay 3TR in FIG. lb, the left-hand terminal of relay 3HDR, the right-hand terminal of relay 3HDR, conductor 6, and over the front point of contact b of relay IHDR to battery terminal N1.

Relay 3HDR has a reverse control circuit which may be traced from battery terminal B1 in FIG. la over front contact 0 of relay ISR, the back point of contact I) of relay lI-IDR, conductor 6, the right-hand terminal of relay SHDR in FIG. lb, the left-hand terminal of relay 3HDR, front contact a of relay 2TR, conductor 5, front contact a of relay ZTR in FIG. 1a, the back point of contact a of relay IHDR, and over front contact b of relay 18R to battery terminal N1. Thus, relay SHDR is deenergized when either of the track sections .21 or .31" are occupied, or when relays :IHTDR and 18R are both deenergized. Relay 3I-lDR is energized by current of normal polarity, that is current of the polarity to control the polar contacts of the relay to their normal or left-hand position when relay IHD'R is energized as hereinafter discussed; and is energized by current of reverse polarity, that is, current of the polarity to control the polar contacts of the relay to their reverse or right-hand position, when relay lHDR is deenergized and relay 15R is energized as hereinafter described.

For purpose of simplicity the control circuits for relays lHDR and 4HDR are not shown in the drawings but relay lI-IDR is indicated as controlled by traffic conditions west of signal 1 and relay 4HDR is indicated as controlled by traflic conditions east of signal 4. Relay IHDR is controlled from the first westbound signal location to the west of signal 16 by circuits similar to that shown for control of relay SHDR, and relay 4HDR is controlled from the first eastbound signal location to the east of signal 4G by circuits similar to that shown for control relay ZHDR. This will be apparent to those skilled in the art, and, therefore, it is not necessary to show the circuits for control of relays 'IHDR and 4HDR.

It will also be apparent to those skilled in the art that in a signaling system such as shown in the drawings, the first eastbound signal to the west of signal 2G and the first westbound signal to the east of signal 3G will be controlled from locations A and C, respectively, in a manner similar to that shown for control of signals 16 and 36, respectively. However, since these control circuits are not necessary to make the description complete, the circuits have been omitted from the drawings and only those circuits necessary for an understanding of my invention have been shown.

As previously mentioned, directional stick relays 15R and 25R in FIG. 1a provide for following train move ments in the signaling system shown, as will be more fully discussed later in this description. Relay 18R has a pickup circuit which extends from battery terminal B1 over back contact a of relay lTR, the front point of contact of relay lHDR, and through the winding of relay 18R to battery terminal N1. Relay ISR has a first stick circuit which extends from battery terminal B1 over back contact a of relay lTR, front contact a of relay 18R, and through the winding of relay 18R to battery terminal N1. Relay 15R has a second stick circuit which extends from battery terminal B1 over the back point of contact 0 of relay lHDR, front contact a of relay 15R, and through the winding of relay 18R to battery terminal N1. Thus, relay 15R is energized when signal 16 is controlled, by the energization of relay IHDR, to give a clear or proceed indication and relay ITR is thereafter released by a train accepting signal 16. Relay lSR is thereafter maintained energized so long as relay ITR remains released or so long as relay lHDR remains deenergized after the acceptance of signal 16 by the train.

Relay 28R has a pickup circuit which extends from battery terminal B1 over back contact 0 of relay ZTR, the front point of contact a of relay ZHDR, and through the winding of relay 2SR to battery terminal N1. Relay 28R has a first stick circuit which extends from battery terminal B1 over back contact c of relay ZTR, front contact a of relay 28R, and through the winding of relay 2SR to battery terminal N1. Relay ZSR has a second stick circuit which extends from battery terminal Bl over the back point of contact a of relay ZHDR, front contact a of relay 28R, and through the winding of relay 28K to battery terminal N1. Thus, relay ZSR is energized when signal 26 is controlled, by the energization of relay ZHDR, to give a clear or proceed indication and relay ZTR is thereafter released by a train accepting signal 2G. Relay 28R is thereafter maintained energized so long as relay 2TR remains released or so long as relay ZHDR remains deenergized after the acceptance of signal 2G by the train.

Directional stick relays 38R and 4SR in FIG. 1b, as previously mentioned, also provide for following train movements in the signaling system shown. This will be more fully pointed out hereinafter in this description. Relay 3SR has a pickup circuit which extends from battery terminal B2 over back contact 0 of relay 3TR, the front point of contact a of relay 3l-IDR, and through the winding of relay 38R to battery terminal N2. Relay 3SR has a first stick circuit which may be traced from battery terminal B2 over back contact c of relay 3TR, front contact a of relay 38R, and through the winding of relay 38R to battery terminal N2. Relay 38R has a second stick circuit which may be traced from battery terminal B2 over the back point of contact a of relay 3HDR, front contact a of relay 38R, and through the winding of relay 38R to battery terminal N2. By these circuits relay SSR is energized when signal 36 is controlled, by the energization of relay 3HDR, to give a clear or proceed indication and relay 3TR is thereafter released by a train accepting signal 3G. Relay SSR is thereafter maintained energized so long as relay 3TR remains released or so long as relay 3HDR remains deenergized after acceptance of signal 36 by the train.

Relay 48R has a pickup circuit extending from battery terminal B2 over back contact a of relay 4TR, the front point of contact c of relay 4HDR, and through the winding of relay 48K to battery terminal N2. Relay 48R has a first stick circuit which extends from battery terminal B2 over back contact a of relay 4TR, front contact a of relay 48R, and through the winding of relay 48K to battery terminal N2. Relay 45R has a second stick circuit which extends from battery terminal B2 over the back point of contact c of relay 4HDR, front contact a of relay 48R, and through the winding of relay 48R to battery terminal N2. Thus, relay 48R is energized when signal 4G is controlled, by the energization of relay 4HDR, to give a clear or proceed indication and relay 4TR is thereafter released by a train accepting signal 46. Relay 48R is thereafter maintained energized so long as relay 4TR remains released or so long as relay 4HDR remains deenergized after acceptance of signal 4G by the train.

The circuits for illuminating the lamps of signals 16 and 26 are shown at the bottom of FIG. 1a and will now be traced in detail. The green signal lamp 1GB of signal 1G has an energizing circuit which extends from battery terminal B1 over the front point of contact d of relay I HDR, polar contact e of relay IHDR in its lefthand or normal position, and through the filament of lamp 1GB to battery terminal N1. The yellow signal lamp lYE of signal 1G has an energizing circuit which extends from battery terminal B1 over the front point of contact d of relay 1=HDR, polar contact e of relay IHDR in its right-hand or reverse position and through the filament of lamp 1YE to battery terminal N1. The red signal lamp IRE of signal 1G has an energizing circuit extending from battery terminal B1 over the back point of contact a of relay ll-IDR and through the filament of lamp I'RE to battery terminal N1.

As previously mentioned signal 16 is provided with an additional indication lamp IDEK. The circuit for energizing this lamp extends from battery terminal B1 over back contact b of relay IDEDSR, to be described in detail hereinafter, and through the filament of the lamp to battery terminal N1.

The green signal lamp 2GB of signal 26 has an energizing circuit which may be traced from battery terminal B1 over the front point of contact 12 of relay ZHDR, polar contact c of relay 2 HDR in its normal or lefthand position, and through the filament of lamp 2GB to battery terminal N1. Yellow signal lamp 2YE of signal 2G has an energizing circuit extending from battery terminal B1 over the front point of contact b of relay ZHDR, polar contact of relay ZHDR'in its reverse or right-hand position and through the filament of lamp '2YE to battery terminal N1. The red signal lamp ZRE has an energizing circuit which extends from battery terminal B1 over the back point of contact b of relay ZHDR and through the filament of lamp ZRE to battery terminal N1.

The circuits for illuminating the lamps of signals 3G and 46 are shown at the bottom of FIG. 1b and will now be traced in detail. Green signal lamp 3GB of signal 36 has an energizing circuit extending from battery terminal B2 over the front point of contact b of relay 3HDR, polar contact c of relay SHDR in its left-hand or normal position, and through the filament of lamp 3GB to battery terminal N2. The yellow signal lamp 3YE of signal 36 has an energizing circuit which extends from battery terminal B2 over the front point of contact b of relay SHDR, polar contact 0 of relay 3HDR in its right-hand or reverse position, and through the filament of lamp 3YE to battery terminal N2. The energizing circuit for red lamp 3RE of signal 36 extends from battery terminal B2 over the back point of contact b of relay SHIDR, and through the filament of lamp 3RE to battery terminal N2.

The green signal lamp 4GB of signal 4G is provided with an energizing circuit extending from battery terminal B2 over the front point of contact 0! of relay 4HDR, polar contact e of relay 4HDR in its normal or left-hand position, and through the filament of lamp 4GE to battery terminal N2. Yellow signal lamp 4YE of signal 4G has an energizing circuit which extends from battery terminal B2 over the front point of contact d of relay 4HDR, polar contact e of relay 4HDR in its reverse or right-hand position, and through the filament of lamp 4YE to battery terminal N2. The energizing circuit for red signal lamp 4RE of signal 4G extends from battery terminal B2 over the back point of contact (I of relay 4HDR and through the filament of lamp 4RE to battery terminal N2.

Similarly to signal 16 and as previously mentioned, an additional indication lamp 4DEK is provided on signal 4G. The circuit for energizing this lamp extends from battery terminal B2 over back contact b of relay 4DEDSR, to be described in detail hereinafter, and through the filament of the lamp to battery terminal N2.

In accordance with my invention I provide in conjunction with the above-described signaling circuits, the previously mentioned dragging equipment detector repeater relays IDEDSR and 4DEDSR, and control circuits therefor, at locations A and C, respectively. The aforementioned dragging equipment detector DED having normally closed contacts a and b is provided in the vicinity of location B intermediate locations A and C. .I will first describe in detail the control circuits for relays IDEDSR and 4DEDSR, and will then outline, under specific examples of train movements, the operation of the apparatus of my invention in conjunction with the typical railway signaling apparatus shown.

Relay IDEDSR in FIG. 1a has an energizing circuit which extends from battery terminal B1 over contact a of push button 1PB, closed only when the button is depressed, and through the winding of relay IDEDSR to battery terminal N1. Relay lDEDSR has a first hold ing circuit which extends from battery terminal B1 over conductor 9, contact a of detector DED, closed when the detector is in its unactuated or upright position, conductor 10, front contact a of relay IDEDSR, and through the winding of relay lDEDSR to battery terminal N1. Relay IDEDSR has a second holding circuit extending from battery terminal B1 over front contact b of relay 2SR,front contact a of relay lDEDSR, and through the winding of relay IDEDSR to battery terminal N1.

Relay 4DEDSR in FIG. lb has an energizing cir- -cuit extending from battery terminal B2 over contact a depressed, and through the winding of relay 4DEDSR to battery terminal N2. Relay 4DEDSR has a first holding circuit which may be traced from battery terminal B2 over conductor 12, contact b of detector DED, closed when the detector is in its normal or upright position, conductor 11, front contact a of relay 4DEDSR, and through the winding of relay '4DEDSR to battery terminal N2. Relay 4DEDSR'has a second holding circuit'which extends from battery terminal B2 over front contact b of relay 38R, front contact a of relay 4DEDSR, and through the winding of the relay to battery terminal N2.

From the above traced control circuits for relays IDEDSR and 4DEDSR it is apparent that these-relays are normally energized and once deenergized cannot be reenergized until the push button associated with each respective relay is depressed. In order that only the DEDSR relay for the direction of movement of a train will be released when dragging equipment on the train actuates detector DED, a front contact of the followingmove directional stick relay, associated with the signal which governed the entry of the train into the track stretch, is employed to maintain the other DEDSR relay energized. Otherwise, both DEDSR relays would be released and both push buttons IPB and 4PB would have to be actuated to reenergize each respective DEDSR relay.

All the relays are shown in the drawings in the positions which they occupy when the established direction of tratfic through the railway territory provided with the signaling system shown is from West to east or from left to right as shown on the drawings, and no trains have proceeded by signal 2G. Under these conditions all the directional stick relays SR and signal control relays lHDR and 3HDR are deenergized, relays IDEDSR and 4DEDSR are energized, and relays Zl-IDR and 4HDR are energized and have their polar contacts controlled to their normal or left-hand position by the closure of the previously discussed normal control circuits for these relays. As stated, the direction of traific being shown as established for the eastbound direction, relay lI-IDR will be deenergized at this time and the control circuits for relay 3HDR will be opened at front contacts a and b of relay lHD-R and front contacts b and c of relay 1SR.

Each of the signals 2G and 4G is at this time displaying its green signal lamp to give a clear indication, and relays iHDR and 3HDR being deenergized at this time, the red signal lamps for signals 16 and 36 are illuminated.

I will now describe the operation of the apparatus of my invention when an eastbound train accepts the clear indication given by the illuminated green lamp 2GB and enters the track stretch A-C, and dragging equipment on the engine or a car of the train actuates the dragging equipment detector DED.

When the eastbound train accepts cleared signal 2G and enters track section 2T, relay 2TR is released, and opens its front contact b in the control circuit for relay 2HDR and closes its back contact c to close the pre viously described energizing circuit for relay ZSR including the back contact c of relay ZTR and the front point of contact a of relay 2HDR. Relay 2HDR, as previously pointed out, is slow to release and retains the front point of its contact a closed for a suflicient period of time, after the opening of its control circuit at front contact b of relay 2TR, to permit back contact 0 of relay 2TR to close and complete the pickup circuit for relay 25R. The energization of relay 25R closes at its own front contact a the first stick circuit for maintaining the relay energized over the back point of contact c of relay 2TR while track section 2T is occupied. When the slow release period of relay ZHDR has expired, that relay releases to establish the second stick circuit for relay 2SR including the back point of contact a of relay ZHDR artisan? circuit serves to maintain relay 28R energized when the train vacates track section 2T, but continues :to occupy track section 3T, since the energizing circuit for relay 2HDR remains open at front contact b of relay SIR at this time.

The energization of relay 28R as described above closes the previously described second holding circuit :for relay l-DEDSR including front contact b of relay 28R. Relay iDEDSR will thus be energized so long as relay 28R is energized.

When the previously mentioned dragging equipment on the engine or car of the train actuates the detector plates of dragging equipment detector DED, contacts a and b of the detector DED are momentanily'opened until the dragging object clears .the detector. The momentary opening of contact a of detector DED opens the previously described first holding circuit .for relay IDEDSR, but the second holding circuit for that relay being closed at front con-tact b of relay 25R, relay I'DEDSR remains energized. The momentary .opening of contact I) of detector DED opens the previously described first holding circuit for relay dD EDSR and, the second holding circuit for that relay over front contact 12 of relay 45R being open at this time, relay 4DEDSR releases, opening its front contact a in its previously described holding circuits. When contact -b of detector DED closes, after the dragging object clears the selfrestoring detector, the holding circuits for relay 4DEDSR remain open at front contact a of relay '4DEDSR and the relay remains in its released position.

The release of relay 4DEDSR closes the previously described circuit for illumination of the signal lamp 4DEK of signal 46. This circuit extends from battery terminal B2 over back contact b of relay -4DEDSR and through the filament of the lamp to battery terminal N2. Thus, lamp 4DE-K is illuminated to give an indication to the engineman of the train that the train has hanging or dragging equipment and must be stopped for repairs. The dragging equipment indication may by operating rules be made an absolute stop indication or, by obvious circuitry not shown in the drawings, the red signal lamp 4RE of signal 46 may be illuminated in conjunction with lamp 4DEK.

As is apparent, there must be sufiicient distance between signal 4G and the location of the dragging equipment detector that the entire length of the longest train to traverse track stretch A-C is past the detector before the engine of the train passes signal 4G, otherwise no indication will be given to the engineman *of the train when equipment is hanging or dragging from :that part of the train not yet by the detector. This condition is also applicable to the distance between signal 16 and the location of the detector, as is believed obvious.

When the dragging equipment on the train has been removed or repaired, the engineman or other railway personnel may depress push button APB to reenergize relay 4DEDSR over its previously described pickup circult and the train may then proceed in its eastbound direction.

When the train passes signal 46, following-move directional stick relay 48R is energized over its previously described pickup circuit. The energization .of relay 48R prepares at its front contacts b and c the reverse control circuit for relay ZHDR. When the train vacates track section 2T, relay ZTR will pick up and complete at its from contact b the reverse control circuit for relay ZHDR at location A. The closing of the front -.point of contact b of relay ZHDR and the reverse point of the polar contact c of relay ZHDR will close the previous-1y described energizing circuit for yellow'signal lamp 2YE of signal 26, and a following train may enter track section 2T. This is the-usual operation in railway signaling systems having provisions for following train movements, such as the system shown in the drawings.

When the established direction of traffic through the railway territory provided with :thesignaling system shown is in :the westward direction or from right to left as shown on the drawings, and ;-no trains have proceeded by signal 36, all the directional stick relays ,SR and signal control relays ZH'DR and 4HDR are deenergized, relays i'DED'SR and 4DEDSR are energized, and relays IHDR and SHDR are energized and have their polar contacts controlled to their normal or left-hand position by the closure of thepreviously discussed normal 'control circuits for these .relays. :However, the operation of the apparatus for a westbound train moving through the track stretch and having dragging equipment being similar to that just described for an eastbound train, :no description of the "operation of the apparatus and circuitry for the westbound train movement is believed necessary.

From the foregoing description it is apparent that, with the arrangement of apparatus of my invention as'shown in the drawings of this application, I have provided, .in conjunction with an automatic signaling system .for a stretch of double direction running single track railway having provisions for following train movements, means for employing a single dragging equipment detector to detect objects hanging or dragging from trains moving over the stretch in either direction and to provide a dragging equipment indication for only the direction in which a train actuating the detector is moving. This opera tion of the apparatus of my :invention is accomplished without additional :means for indicating the direction of train movements, by "making use of existing directional indicating means employed for following trainmovements in railwaysignaling system of the type described.

While I have shown and described only one form .of apparatus embodying my invention, it should be understood that various changes and modifications may be made therein within the scope of the appended claims and without departing from the spirit and scope of my invention.

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

1. In astretch of railway track provided with a pair of entering and exit signals at each 'end for governing train movements into and out of the stretch, a directional stick relay associated witheach pair of signals, and means. for energizing each stick relay when its associated enter ing signal is cleared for a train movement and a train accepts the cleared signal; the combination comprising, a self-restoring dragging equipment detector in said stretch operable "to two extreme positions and normally biased to an intermediate position, a plurality of normally closed contacts, means controlled by said detector for opening said contacts when the detector is operated from its biased position, a push button associated with each pair of signals and normally biased to a first position and manually operable to a second position, a repeater relay associated with each push button, means controlled by each push button in its operated position for energizing the associated repeater relay, means controlled by said contacts in their closed position for maintaining each repeater relay energized when once energized .by operation of the associated push button, means controlled by each said directional stick relay in its energized position for maintaining the associated repeater relay energized when once energized by operation of the associated push .button, an indication device associated with each repeater relay and mounted on the .associated exit signal, and means controlled by :each repeater relay in'its deenergized position for controlling the associated indication device to display a dragging equipment indication.

2. %In a stretch of railway track provided with first and second pairs of entering and exit signals at first and second ends .of the stretch respectively, for governing train movements into and out of the stretch, a directional stick relay associated with each pair of signals, and means for energizing each directional stick relay when its associated entering signal is cleared for a train movement into the stretch and a train accepts the cleared signal; the combination comprising, a self-restoring dragging equipment detector in the trackway of said stretch and operable to two extreme positions and normally biased to an intermediate position, a plurality of contacts associated with said device and normally in a closed position and operable to an open position when the device is operated from its intermediate position, a first detector relay associated with the directional stick relay associated with the first pair of signals, a second detector relay associated with the directional stick relay associated with the second pair of signals, a manually operable circuit controller associated with each detector relay, means controlled by each said circuit controller for energizing the associated detector relay when the controller is operated, means controlled by the associated stick relay for maintaining the first detector relay energized when once energized and the stick relay is energized, means controlled by the associated stick relay for maintaining the second detector relay energized when once energized and the stick relay is energized, means controlled by said contacts in their closed position for maintaining said detector relays energized when once energized, a first dragging equipment indicator associated with the first detector relay and its associated leaving signal, a second dragging equipment indicator associated with the second detector relay and its associated leaving signal, and means controlled by each detector relay for controlling the associated indicator to give a dragging equipment indication when the detector relay is deenergized.

3. In a stretch of railway track provided with first and second pairs of entering and exit signals at first and second ends of the stretch respectively, for governing train movements into and out of the stretch, a stick relay associated with each pair of signals, and means for energizing each stick relay when its associated entering signal is cleared for a train movement into the stretch and a train passes the signal and for maintaining the relay energized so long as the train occupies the stretch;

the combination comprising, a self-restoring dragging equipment detector in the trackway of said stretch biased to a normal position and operable from that position; a plurality of contacts associated with said device and normally in a closed position and operable to an open position when the device is operated, a device repeater relay associated with each stick relay and its associated pair of signals, a manually operable circuit controller for each device repeater relay, each controller having a normally open contact operable to a closed position when the controller is operated, means controlled by each coni troller contact in its closed position for energizing the associated device repeater relay, means controlled by a front contact of each stick relay in its closed position for maintaining the associated device repeater relay energized when once energized, means controlled by said contacts associated with said device in their closed position for maintaining each device repeater relay energized when once energized, a dragging equipment indication device associated with each said leaving signal and its associated device repeater relay, said devices normally giving no indication and capable of giving a dragging equipment indication when actuated, and means controlled by a closed back contact of each device repeater relay for actuating the associated indication device.

4. In a stretch of railway track provided with first and second pairs of entering and exit signals at first and second ends of the stretch respectively, for governing train movements into and out of the stretch, a stick relay associated with each pair of signals, means for energizing each stick relay when its associated entering signal is cleared for a train movement into the stretch and a train passes the signal, and means for maintaining each stick relay energized when once energized so long as the train occupies the track stretch; the combination comprising, a self-restoring dragging equipment detector disposed in the trackway of said stretch and normally biased to an unoperated position, a plurality of contacts closed when and only when the device occupies its unoperated position, a detector repeater relay associated with each said leaving signal and the associated stick relay, a manually operable contact associated with each detector repeater relay, each contact normally biased to an open position and manually operable to a closed position, a pickup circuit for each said repeater relay including its associated manually operable contact, a first stick circuit for each said repeater relay including a front contact of its associated stick relay, a second stick circuit for each said repeater relay including one of its own front contacts and one of said detector contacts, a dragging equipment indication device associated with each said leaving signal and operable when energized to give a dragging equipment indication, and an energizing circuit for each said indication device including a back contact of the associated detector repeater relay.

5. In combination with a stretch of railway track extending between first and second locations, a pair of entering and leaving signals at each said location for governing train movements into and out of the stretch respectively, track occupancy detection means for said stretch, a stick relay associated with each said pair of signals, a signal control relay for each said entering signal, means controlled by each said control relay and said track occupancy detection means for energizing the associated stick relay when the associated entering signal is cleared to permit a train to move into the stretch and the train passes that signal, means controlled by said track occupancy detection means for maintaining each energized stick relay energized so long as the train occupies the track stretch, a self-restoring dragging equipment detector biased to a normal position and disposed in the trackway of said stretch, a detector repeater relay at each of said first and second locations, a manually operable circuit controller associated with each of said repeater relays and biased to a normal position, means controlled by each said controller for energizing said associated detector repeater relay when the controller is operated, means controlled by each said stick relay for maintaining the associated detector repeater relay energized when once energized and the stick relay is en ergized, means controlled by said detector in its said normal position for maintaining each detector repeater relay energized when once energized, a dragging equipment indication lamp on each said leaving signal, and means controlled by each said detector repeater relay for energizing the associated indication lamp when the repeater relay is deenergized.

6. A directional dragging equipment detector system for a stretch of track having an exit signal and an entering signal at each end, a directional stick relay associated with each entering signal, and means associated with each entering signal and controlled by the entrance of a train into said stretch for energizing the associated stick relay; comprising, in combination, a self-restoring dragging equipment detector disposed in the trackway of said stretch, a dragging equipment indication lamp on each said exit signal, means controlled by said detector and said stick relays for energizing only that indication lamp at the exit end of the stretch for a train when dragging equipment on the train actuates the detector, a manually operable circuit controller at said exit end of the stretch, and means controlled by said circuit controller for deenergizing the energized indication lamp when the controller is operated following a pe riod of energization of the lamp.

No references cited.

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