US2581108A - Dragging equipment detector signaling system for railroads - Google Patents

Description

J. J. JACOBUS IFMEN Jan. 1, 1952 DRAGC-ING EQU T DETECTOR SIGNALING SYSTEM FOR RAILROADS Filed March 6, 1947 zzzzzou MEOQTJ Il :Suvenfor i vGttorneg www 22222D2200 moon NO ...O JOMMIOU n mZoIamJmF @E I. Qdi 3mm@ ,5&28

Patented Jan. 1, 1952 DRAGGING EQUIPMENT1 DETECTOR SIG- NALIN G SYSTEM FOR RAILROADS John J. Jacobus, Greece, N. Y., assigner to General Railway Signal Company, Rochester, N. Y.

Application March 6, 1947, Serial No. 732,781 8 Claims, (Cl. 246-219) This invention relates to signaling systems for railroads, and it more particularly pertains to means for indicating the presence of dragging equipment upon the passage of a train over a detector barrier disposed across the trackway.

The present invention is to be considered as providing improvements in the dragging equipment detecting system disclosed in the prior application of G. H. Dryden, Ser. No. '731.735, led March l, 1947.

An object of the present invention is to automatically restore an oilice controlled signal to stop upon the momentary actuation of a yieldable dragging equipment detector barrier included in a track section located one or more track sections in the rear of that signal, and to distinctively indicate such detection at the oice.

Another object of the present invention is to locate the detector barrier in a track section several track sections in the rear of the signal it governs for the purpose of preventing the changing of the indication of the signal governing exit from that track section in which the barrier is located because of actuation of the barrier, and yet prevent a following train, in actuating the barrier, from putting the oflice controlled signal to stop for a iirst train.

Another object of the present invention, where several track sections are included between av barrier and an oiiice controlled signal, is to cause each train to be stopped by the detector barrier control of the oilice controlled signal, only if that train has actuated the detector barrier, irrespective of whether or not each of the several track sections between the barrier and the oiiice controlled signal is occupied by a train.-

Another object of the present invention is to provide a distinctive indication for a signal in approach to the office controlled signal when the oiiice controlled signal is put to stop by reason of the actuation of a dragging equipment detector barrier.

Another object of the present invention, rwhen an operator at theioiilce has been notied that a train is ready to proceed afterhaving been stopped by an oiiice controlled signal for checking dragging equipment, is to allow the operator at the oflice, by actuation of specially manually controlled means, to cause the ofce controlled signal to be cleared, irrespectiveof the eiectiveness of the dragging equipment detector means that has put that signal to stop.

Other objects, purposes', and characteristic features of the present invention will` be in part obvious from the 'accompanying drawings and ini part pointed out as the description of the invention progresses.

In describing the invention in detail, reference is made to the accompanying drawing in which Fig. 1 illustrates one embodiment of the present invention as applied to a stretch of railway track assumed to be remotely located from a control olice, and Fig. 2 illustrates a modified circuit organization that may be employed in accordance with the requirements of practice. Fig. 3 is a sectional elevational view of a detector barrier disposed across a stretch of railway track.

For the purpose of simplifying the disclosure of the present invention the organization of the system according to the present invention is illustrated by a schematic Wiring diagram in a manner to more particularly disclose the mode of operation and the principles involved in the present invention, rather than for the purpose of illustrating the specific instruction and arrangement of parts that would be employed in practice. The symbols and have been used to indicate connections to the respective positive and negative terminals of suitable batteries or other sources of direct current.

The trackway of this embodiment of the present invention is illustrated as being divided into track sections IT, 2T, 3T, 4T and 5T, each track section having a track relay TR associated therewith in a conventional manner. The signals 2, 3, 4 and 5 are provided for governing entrance into the respective track sections 2T, 3T, 4T and 5T for a direction of traffic to the right, which, for the purpose of this disclosure, is assumed to be for eastbound traffic.

The signals .are assumed to be of the searchlight type such as is shown, for example, in the patent to O. S. Field, No. 2,239,316, dated April 22, 1941, although it will be readily apparent that other types of signals such as semaphore, position light, or color light signals having individual color lamp units, could as well be employed. The signal 5 is illustrated as having conventional upper and lower arm signals for governing traflic through the track switch W in its respective normal and reverse positions. The signal 5A governs traflic through the track switch W in its normal position, and the signal 5B governs traine over the track switch W in its reverse position. The

track switch W is preferably power operated from the control oice according to usual practice.

Disposed across the trackway in the track section 2T, and preferably near the signal 2, is a detector barrier DB which is biased to an upright positionby a suitable biasing mechanism BM, and

connected to the circuit controller C. The circuit controller C provides a suitable housing for the contact DEC and a means for opening such contact when the barrier B is actuated by an eastbound train. Inasmuch as it is contemplated that the structure of the barrier DB, the biasing mechanism BM, and the circuit controller C, for this embodiment of the present invention, be of the general character fully disclosed in the above mentioned application of G. H. Dryden, it is believed unnecessary for the purpose of this application to disclose all oi the details of the structural organization of the dragging equipmentdetector. Although the barrier DB for this embodiment of the present invention is assumed to be actuated only by eastbound traflic, if there is a possibility of westbound trains being run over the trackway, the circuit controller C should have a structure 5B both being at stop in a manner such as is disclosed, for example, in the T. J. Judge Patent No. 2,298,946, dated October 13, 1.942, for the control of relay IGRGP in Fig. 4 of that patent.

In accordance with the normally closed position of the contact DEC of the dragging equipment detector, a detector stick relay ZDES is normally maintained picked up by an obvious stick circuit including contact DEC and front contact l5 of relay 2DES.

With relay ZDES in its picked-up position, the

' stick relay 3DES, which is more particularly' associated with the track section 3T, is maintained picked up by its stick circuit including front contact llinofnrelay 2DES and front contact il of relay 3DES.

Similarly the relay ADES, which is more particularly associated with the track section 4T,

as fully disclosed in such Dryden application so as to prevent the openingI of contact DEC in case the barrier DB is actuated by the passage of westbound trains.

With reference to Fig. 3, the detector barrier DB extends across the track Way between two railway ties 35. This barrier comprises at its base a square rod to which ,is secured side plates 3l extending upwardly to a height to be actuated by equipment dragging beneath a train. The rod 3o is journaled by a suitable bearing 38 ateach end of the rod, and the rod 3c at the end illustrated has a suitable operating crank 39 secured thereto which extends upwardly and operates an actuating rod 4B, the rod 4e being connectedy to the crank 39 by a suitable adjustable lug di. The bearing 38 at each end of the rod 35 is secured by suitable bolts 42 toa supporting bracket d3 which is secured across the ends of the ties 35. Y

Although various means Well-known to those familiar with the art can be employed for the manual control of signal 5 and of the track switch W, it is assumed that this embodiment of the present invention is a part of a conventional centralized traffic control system in which an operator, or a dispatcher, at the control oice maintains communication with his respective manually controlled switches and signals by a code communication system over a- CTC line circuit as illustrated in block form and by dotted lines in the accompanying drawing. It is to be Vunderstood that the code communication apparatus can lbe provided according to Various suitable code communication systems such, for example, as according to the system fully disclosed in the patent to W. D. Halles et al., Pat. No. 2,399,734, dated May 7, 1946, to which reference is to be made for a more complete disclosure of the cornrnunication system.

It is illustrated that a signal control lever SGL is provided at the control cnice for the designation of the respective stop and proceed indications to be displayed by signal 5. The signal SGL is illustrated as being normally in its center (at-stop) position, and in accordance therewith energy is applied to wire I2 through the normally closed contact I4 o the lever SGL to select a stop control for transmission to the signal 5 in case the code communication apparatus is set into a cycle of operation for transmission of controls to that field station. The signal 5, however, is assumed to bein its stop indication position as is normally effective by the slotting of that signal upon the passage of a train. With signals 5A and 5B both at stop, the stop repeater relay 5RGP is normally energized in accordance with the signals 5A and is maintained normally picked up by a stick circuit including front contact I8 of relay 3DES and front contact I9 of relay dDES.

In accordance with the relay ADES being in its pickedeu'p position, the circuit including wire 101 is opened at back contact 24 to condition the selection of an indication for transmission by the code communication apparatus to the control ofiice of a character to cause the dragging equipment detector indication lamp DK, which is illustrated as being connected by wire l!! to the code communication apparatus, to be deenergized.

The relays GZ, B and DCS, which are assumed to be subject to control of an operator at the control cnice via the code communication system, are normally deenergizedfand are used for purposes governing the control of signal in a manner to be hereinafter considered.

Having thus described the conditions which are assumed to be the normal conditions of the sys* tem to which the system is restored subsequent to the passage of trains`, consideration will now be the mode of operation of the system according to a typical assumed operating condition for the passage of an eastbound train.

In anticipation of the approach of an eastbound train, the dispatcher" actuates the signal control lever SGL toits right-hand position to allow the clearing of the signal 5A (assuming t e track switch W to be in its normal position). When the code communication system apparatus is set into operation for the communication of such control to the field, the application of energy by the contact I4 of lever SGL to wire l5 is eiective momentarily during the control cycle of operation of the code communication apparatus to apply energy to wire i31, and thus to the upper winding of the signal control relay 5GZ to cause the picking up of that relay.

The picking up oi relay EGZ (with the relay ADES picked up) closes a stick circuit for the lower Awinding of that relay. Such circuit extends rom (-1-), including front contact 2e oi e track relay STR, back contact 2l of relay B, front contact22 of relay 5G-Z, and front contact 23 or relay ADES, to

A consideration of this stick circuit reveals that the relayA SGZ can be dropped away due to any one of three conditions. One o the conditions for the opening of the stick circuit for the relay 5GZ is that the track section 5T become occupied by a train, as upon the acceptance of the signal 5A by an eastbound train, to open front contact 28 of relay STR. Another condition under which the stick circuit for the relay iGZ can beopened is by the restoration of the lever SGL to its center position to apply energy to the wire I2' through contact I4 and by the operator setting the code communication system into' operation whereby energy can be applied momentarily at the field station to the wire |21, and thus to the winding of relay B. The picking up of relay B is effective to open the stick circuit for relay EGZ at back contact 2|. It is also provided that the relay GZ can be dropped away by the opening of its stick circuit at front contact 23 of relay DES as by the actuation of the detector barrier DB in a manner to be hereinafter considered.

The picking' up of relay 5GZ in a manner which has been described is effective by the closure of front contact 25 to allow the clearing of signal 5A or signal 5B, as selected by the position of the track switch W, and by automatic track circuit control, all of which selections are not shown but are well known to those skilled in the art, and have been merely indicated by dotted lines for the purpose of smplication of this disclosure.

The signals 2, 3 and 4 are assumed to be conventional automatic block signals which are normally clear, in accordance with the condition of occupancy of the various blocks in advance thereof. Thus, assuming the trackway to be unoccupied by trains, signal 4 provides a caution indication when signal 5 is at stop as an indication to a train in approach of signal 4 to proceed prepared to stop at signal 5. Assuming the signal 5A to be cleared as described above the signals 2, 3 and 4 are all clear. Although the circuits for the controls of signals 2, 3, and 4 has not been shown, it will be readily apparent to those skilled in the art that these signals may be controlled in accordance with practically any of the well-known signal control systems generally employed in practice.

It will be assumed that an eastbound train accepts the clear signal 2 at a time when the signals 2, 3, 4 and 5A are clear, and that such train passes over the detector barrier DB. It will also be assumed that the detector barrier DB is actuated by dragging equipment beneath the train,

'and thus the contact DEC is momentarily opened.

Upon the opening of such contact, the stick circuit which has been described for the relay DES is interrupted, and thus the relay ZDES is dropped away. The restoration of the contact kDEC to its normally closed position does not cause the restoration of the relay ZDES because the presence of the train in the track section 2T causes the track relay 2TR to be dropped away, and the closure of front contact 25 of relay ZTR is essential to allow relay ZDES to be picked up. Relay ZDES, therefore, is not restored until the track section 2T becomes unoccupied in the rear of the train.

Upon the dropping away of relay ZDES, the relay 3DES is dropped away because of the opening of its stick circuit at front contact I5. The front contact 21 of the track relay 2TR that is connected in multiple lwith front contact I 5 of relay 2DES is open at that time because of the presence of thetrain in the track section 2T.

Upon the dropping away of relay 3DES, the relay 4DES has its stick circuit opened at front contactI I8 but, assuming the eastbound train as yetnot to have entered the track section 3T, the front contact 28 of relay STR is maintained closed to supply energy to the stick circuit for relay 4DES to maintain that relay pickedup. 1 Assumingl further'pas'sage o f the eastbound train so as to accept the signal 3 and enter the track section 3T, the dropping away of relay 3TR, by the opening of front contact 28 With the 'front contact I8 of relay v3DES already open, lremoves energy from the stick relay 4DES to lcause that relay to be dropped away. v

The relay 4DES in dropping away opens the stick circuit for the lower winding of relay 5GZ `at front contact 23, and causes the relay 5GZ to -signal 5A is restored to stop upon the opening of front contact 25 of relay 5GZ in order that the train in approach of signal 4 may be stopped at signal 5 for checking its cars for dragging equipment.

In accordance'with the putting to stop of signal 5A, the signal 4, because of its automatic control, changes its indication from clear to caution, and in order that the trainmen of the approaching train may be informed that the train is being stopped because of the dragging equipment detector being actuated, a special indicator lamp at signal 4 in the form of the lunar white lamp LW is energized. This lamp is energized in accordancewith the dropping away oi' the relay 4DESy in response to the actuation of the dragging equipment detector barrier DB in an obvious manner upon the closure of back contact 3B. It is thus provided that the eastbound train will reduce its speed in accordance for the energization of lamp DK at the control oice.

When the track section 2T becomes unoccupied in the rear of the train, the closure of front contact 26, upon the picking up of relay 2TR, closes an obvious pick-up circuit for the relay ZDES, thus allowing the stick circuit to be again established for that relay so that front contact I5 of relay ZDES shunts front contact 25 of relay ZTR out of the control circuit and renders thev continued energization of relay ZDES dependent entirely upon the contact DEC of the dragging equipment circuit controller C.

Assuming the eastbound train to accept signal 4 and leave the track section 3T, the picking up of relay 3'I'R in the rear of the train is efiective bythe closure of front contact SI to cause the picking up of relay 3DES by the closure of the pick-up circuit for that relay. Such pick-up circuit extends from (-I-l, including front contact I6 of relay 2DES, front contact 3! of relay STR, and winding of relay 3DES, to The closure of front contact I'I of relay 3DES shunts front contact SI of relay STR out of the circuit just described to cause the relay 3DES to be maintained picked up, dependent upon the iront contacts I6 and 2'I of relays ZDE'S and 2TR respectively.

There is generally a telephone located near the office controlled signal 5 by which a trainman can communicate' with the operator at the control oiiice to inform the operator when the train has been checked for dragging' equipment and 9 bound train has dragging equipment which actuates the detector barrier DB. In' accordance with the actuation of such barrier, the relay ZDES is dropped away in a manner which has been described, and the dropping away of that relay opens the stick circuit for relay 3DES at iront contact i6, the front contact 2'1 of relay ZTR being opened at that time because of the presence of the second eastbound train in the track section 2T.

The relay 3DES, however, is not dropped away under the above described conditions because the first eastbound train, by occupying the track section 3T, is eiective` to maintain the relay 3DES picked up by a stick circuit including back contact 3| of relay 3TR and front contact |'i of relay 3DES, irrespective of the opening of front contacts I6 and 2'| of relays 2DES and 2TR respectively. Thus, the iirst eastbound train, because it has not actuated the detector barrier DB, maintains the relay 3DES picked up, and

the front contact I8 closed to apply energy to l the relay 4DES for maintaining that relay energized, Thus the stick circuit for the lower wind ing of the signal control relay SGZ is maintained closed at front contact 23.

To consider the mode of operation upon further movement of the eastbound trains, it will be assumed that the rst eastbound train moves into the track section 4T so as to allow the track section 3T to become unoccupied in the rear of that train. In accordance with such train movement, the picking up of the relay STR opens the stick circuit by which the relay 3DES has been maintained picked up at back contact 3|, and thus causes the dropping away of that relay because of the barrier DB having been tripped by the second eastbound train.

The dropping away of relay 3DES, yby the opening of front contact I8 cannot cause the dropping away of relay 4DES however, because energy is applied to that relay through front contact v28 of relay STR at that time, and also through back contact 34 of relay 4TR because of the presence of the first eastbound train in the track section 4T.

Due to the track section 3T being unoccupied in the rear of the first eastbound train, the signal 3 is put to caution to allow passage of the second eastbound train into the track section 3T.

When the track section 2T becomes unoccupied in the rear of the second eastbound train, the picking up of the relay 2TR, by the closure of front contact 26, provides for the picking up of the relay ZDES, but the picking up of that relay, by the closure of front contact I6 cannot effect the picking up of relay 3DES, because the pick-up circuit for that relay is open at that time at front contact 3| due to the presence of the second eastbound train in the track section 3T.

To assume further progress of the trains, it will be assumed that the first eastbound train accepts the signal 5 and enters the track section 5T, and that the track section 4T becomes unoccupied in the rear of the train so as to allow the picking up of the track relay 4TR. The picking up of relay 4'I*l`\l by opening back contact 34 in the stick circuit iolay lDES, causes relay 4DES to be dropped away because of the relay 3DES being dropped away and the track section 3T occupied as a result of the passage of the second eastbound train. The dropping away of relay 4DES, by the closure of back contact 24 applies energyl to wire |01 to effect the transmission during an indication cycle of the code communication system-of,

an indication to the control oilice so as to apply energy at the control office to wire I3, and thus effect the energization of the dragging equipment detector indicator lamp DK.

The operator at the control office, upon observing the illumination of the indicator lamp DK is informed that the second train must stop at signal 5 and check its cars for dragging equipment, and thus he will not designate as signal control for transmission to signal 5 for the clearing of that signal until he receives telephone communication from a trainman informing him that the train has been checked over for dragging equipment and is ready to proceed. Under such conditions, the clearing of signal 5 is accomplished in response to the actuation of the detector cancel button DCB in combination with the signal lever SGL in a manner which has been described.

It will be noted that the dropping of relay ADES, when the track section fi-T becomes unoccupied in the rear of the first eastbound train causes the illumination of the lunar white lamp LW at signal 4 by the closure of back contact Sii, and at that time the picking up of the track relay ATR is effective to allow the signal 4 to indicate caution. It is thus provided that the second east'- bound train can move into the track section 4T under a caution indication, the energization'cf the lunar white lamp LW being effective at signal 4 to inform the trainmen that they must stop at the next signal and check their train for dragging equipment.

-It is vbelieved to be readily apparent that the system control apparatus is restored to its normal condition in a manner which has beendescribed when it is assumed that the eastbound trains under consideration have progressed so as to leave the stretch of trackway illustrated in this embodiment of the present invention.v

Assuming briefly another typical condition in volving the movement of following trains, if a rst eastbound train has actuated the detector barrier-DB and moved into the track section 3T so as to leave the track section 2T unoccupied in' the rear of the train, the picking up of the track relay 2TR allows the restoration of the relay ZDES. The relay 3DES, can be picked up upon the closure of front contact 3| of relay STR when the track section 3T becomes unoccupied' in the rear of the rst train, thus conditioning the dragging equipment detector system so that if the passage of a second train fails to actuate the barrier DB, the signal 5 will not be put to stop for the second train as such train has not tripped the detector barrier DB.

Although the dragging equipment detector organization according to Fig. l can be rendered eiective only when a train is in the track section with which the detector 'barrier' is associated, there are some conditions to be encountered in practice where there is a possibility of the barrier DB being actuated manually by an unauthorized person after` a train has passed over the barrier, but while the train is still within that track section. Such condition might readily be found where the barrier DB is located near a highway crossing, and the track section with which the barrier is associated is of considerable length so that the train could very readily still be in the track section lwith which the barrier DB is associated at a time when such barrier could be actuated by an unauthorized person passing along the highway.

If it is desired to preventksuch unauthorized operation from being rendered effective, the relay 3DES may have its control circuit modined as illustrated in Fig. 2, for example, so as toY allow the tripping of the yieldablebarrier DB to be effective to put the signal to stop'onlywhen the track sections 4T and 2T are simultaneously occupied. ln accordance with this arrangement the detector barrier DB is located relatively close to the entrance end of the track section 2T for purposes of allowing its response to dragging equipment of the last cars of a train to be effective to put the signal 5 to stop.

It is thus provided that the relay 3DES, according to Fig. 2, is maintained picked up by stick circuit means'corresponding to that which has been described except that front contact 36 of relay ITB, is added in multiple with the front contact 2l of the relay 2TH.

According to the circuit organization of Fig. 2, it is desirable that the track relay ZTR be relatively quick in dropping away so that the relay 2TR-is dropped away immediately upon the entrance of a train into the track section 2T, the front contact 36 of the relay ITR, having been previously opened due to the presence of the train in the track section IT Thus, by the track relay 2THJ being relatively quick acting, the actuation of the barrier DB by equipment dragging from beneath the front of the train can be rendered effective to cause the signal 5 to be put to stop.

The track relay ITR is made suniciently slow in picking up to allow the actuation of the detector barrier DB by equipment draggingbeneath the last cars of the train to be effective to put the signal 5 to stop. ln other words, the track relay `ITB, is made sufficiently. slow in picking up to allow the rear of the train to pass over the barrier DB so as to render the actuation of the barrier DB beneath any car ofthe train effective to put signal 5 to stop.

The circuit organization just described is obviously effective tb prevent the manual actuation of the barrier DB after passage of a train from being effective to put the signal 5 to stop (assuming the train to still be in the track section 2T), provided of course that there is no following train entering the track section i T. The entrance of such following train into the track section IT would of course drop the relay ITR at a time when the relay ZTR is dropped away and thus rendered the control of signal 5 subject to the actuation of the barrier DB although there is no train passing directly over the barrier at that time. It will be readily recognized however that this is an extraordinary condition which would not generally be encountered in practice, and that the requiring of the track relays lTR and ZTR to be both dropped away to render-the signal 5 subject to actuation ofthe barrier DB generally requires that the barrier DB be actuated when under a train in order for it to be effective.

Having thus described a signaling system comprising dragging equipment Ydetector apparatus for a specific stretch of trackway as one embodiment of the present invention, it is desired to be understood that this form is selected to facilitate the disclosure of the invention ratherthan to limit the number of forms which the invention may assume, and it is to be further understoodY that various alterations, modifications and adapv tations may be applied to the specific form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention except as limited by the. appending claims.

l2 WhatI claim is: 1. In a signaling system yforfa stretch of railway track Ahaving a manually controlled signal for governing a given direction of trailic and hav ing a plurality of track-sections in approach to said signal, a train actuated barrier across said track in one of said track sections, electro-responsive means effective to allow the clearing of said signal in response to a manual control, said electro-responsive means being effective to put said signal to stop in response to the actuation of said barrieri and circuit Ameans for rendering said electro-responsive means non-responsive to the actuation of said barrier if said barrier is actuated when its associated track -section is unoccupied by a train.

2. Inv a signaling system for a stretch of rail Way track divided into respective first and second track sections for a givenvdirection of traiilc and having afsignal for governing passage of a train out of saidsecond track section for said given direction of trafilc, a dragging equipment detector `barrier disposed across the trackway in said rst track section, said barrier having a normally closed contact momentarily opened when said barrier is actuated by equipment dragging from beneath a train, a detector stick relay having va stick circuit including said normally closed contact, said stick relay having a pick-up circuitclosed'only when said first track section is unoccupied, and-circuit means dependent upon the dropping away or said detector `stick relav for putting said signal-to stop.

3. A signalling system for railroads compris ing in combination, a stretch of track having several track sections inapproach to a signal' a dragging equipment detector barrier disposed across the trackway in the track section mostremote-from said signal, a stick relay for each of said track' sections, stick circuit means for maintaining said stick relay energized dependent upon the'energization of the stick relay for the next adjoining track section away from said signal, said stick circuit means for the first of the stick relays being subject to deenergization by the actuation of said barrier, whereby said stick relays are tumbled down for the respective track sections in approach to said signal in response to the actuation of said barrier, track circuit governed-means for rendering the initiation of the tumble-down ineffective in response to the actuation of said barrier if the track section in which the barrier is disposed is unoccupied, and signal control means for putting said signal to stop upon actuation of said barrier only providedthat the-tumble-down of all of said stick relays has become effective.

4f. Ina signalling system for a stretch of rail"- way track divided into several track sections approaching aA signal comprising in combination, a draggingV equipment detector-barrier of the selfrest'oring type disposed across the trackway in the track section most remote from said signal and biased to an upright position, a normally closed contact` subject to actuation only when said barrier is depressed from its upright posi-- tion, a two-position electroresponsive means normally assuming one of said two positions and controlled to its other of said two positions byl a momentary opening of said normally closed contact only if atrain is in approach to said signal, said electroresponsive means remaining` in its said other position throughout the presence of suchtrain unlessl manually restored, a signal control relay" effective when picked up to clear:

said signal, a stick circuit for said signal control relay maintained closed only if said electroresponsive means is in its said other position, and circuit means eiective to restore said electroresponsive means to its said one position in response to a manual control provided said signal control relay is subsequently picked up.

5. In a railway signaling system having first and second signals respectively governing a given direction of trac through a stretch of traqkway and a track section in approach to each signal, a dragging equipment detector barrier disposing across the trackway, signal control means allowing the clearing of said second signal, said signal control means being eective to put said second signal to stop in response to the actuation of said barrier by equipment dragging beneath a train, and detector indication means associated with said rst signal eiective to indicate distinctively when said barrer has been actuated as compared to the signal indications normally provided upon passage of trains which do not actuate the detector barrier, whereby said rst signal indicates distinctively to an approaching train that such train is being stopped at said second signal because of said barrier having been actuated by equipment dragging beneath the train.

6. In a signaling system for a stretch of track having a signal manually controlled from a control oii'ice, a dragging equipment detector barrier disposed across the trackway in approach to said signal, circuit means momentarily effected for manually controlling said signal from the control oce to permit said signal to clear, stick circuit means for said signal normally eiective to allow said signal to remain clear until it is accepted by a train, detector circuit means responsive to the actuation of said dragging equipment detector barrier for rendering said stick circuit means ineiective, and circuit means manually controlled from the control oiiice for rendering said detector circuit means ineiective and thereby permit the clearing of said signal.

7. In a signaling system of the character described for a stretch of track having several track sections in approach of a signal, a dragging equipment detector barrier disposed across the track in the track section most remote from said signal, a stick relay for each of said track sections, stick circuit means for maintaining each of said relays energized dependent upon the energization of said stick relay for the next adjoiningtrack section away from said signal, said stick relay for said track section in which said barrier is disposed being 'subject to deenergization by the actuation of said barrier, and stick circuit means for each of said stick relays except said stick relay associated with said barrier for maintaining the stick relay energized when its associated track section is occupied by a train, irrespective of the actuation of said barrier, and circuit means responsive to the deenergization of said stick relay for the track section immediately in approach of said signal for putting said signal to stop.

8. In a signaling system for a stretch of railway track having a manually controlled signal for governing a given direction of trafc and having a plurality of track sections in approach to said signal, a dragging equipment actuated barrier disposed across the track in one of said track sections, electro-responsive means for permitting the clearing of said signal in response to a manual control, said electro-responsive means being effective to put said signal to stop in response to the actuation of said barrier, and circuit means for rendering said electro-responsive means eiective to put said signal to stop only when said one track section and an adjoining track section are simultaneously occupied.

JOHN J. JACOBUS.

REFERENCES CITED The following references are of record in the le of this patent:

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