US2705280A - Apparatus for control of highway crossing gates - Google Patents

Description

J. E. M MAHON, JR

APPARATUS FOR CONTROL OF HIGHWAY CROSSING GATES Filed Feb. 27, 1951 INVENTOR. mm? Awmm m QQM NW lllmlhmlll Nu 5 ww M \QNQQg (m B m a .VQQQ E Rfikfi 1.... lllill|lli|lll||| mw N 1N V QN bL Mw" m Q N m m. m M 1 m gfi w; m m m m =N m m wLmv 1mm N m Mwx g m MKS a l m. N Q58 1 mm MENN www QRNN A a 1M 5 7* E M um 4 l N RH Q AT E m A T $5 MN 5% 1 MN 9 March 29, 1955 APPARATUS FOR CONTROL OF HIGHWAY CROSSING GATES James E. McMahon, Jr., Penn Township, Allegheny County, Pa., assignor to Westinghouse Air Brake Company, a corporation of Pennsylvania Application February 27, 1951, Serial No. 212,882

8 Claims. (Cl. 246-130) My invention relates to apparatus for the control of highway crossing gates, and has particular reference to systems for automatically controlling such gates by railway trafiic. More particularly my invention relates to the provision of novel and improved means for controlling the operation of highway crossing gates.

In systems of the described type the highway crossing gates are normally held in a vertical or non-obstructing position as long as the approach track sections are vacant but are lowered to a horizontal or obstructing position whenever a train enters an approach section. The approach sections are each of a length sufiicient to assure that the gates will reach their obstructing positions not less than a predetermined interval prior to the time that the head end of the train enters the intersection. Warning devices, such as bells or lights or both, are usually provided at or near the gates and are caused to operate during the time the gates are being lowered, as well as for an interval before the lowering operation is initiated. This operation of the warning devices for a short interval prior to the lowering of the gate arms, provides a preliminary warning period for informing highway trafiic that the gates are about to be lowered, and thereby guards against lowering the gates immediately in front of or on top of highway vehicles.

Operating mechanisms are also provided for raising the gates to their vertical positions after the train which has caused their lowering clears the intersection. However, this operation requires several seconds to complete and a second train might enter an approach section before the gates reach their vertical positions following the passage of the first train. In such event, it is undesirable to stop operation of the gates and permit them to drop immediately, since highway traffic would then have no warning of the release of the gates and might become trapped on the intersection or struck by the descending arms. It is desirable therefore, that in such event the gates be raised to their non-obstructing position before descending, provided of course that the gates reach their obstructing position not less than a predetermined period before the second train reaches the intersection.

It has been proposed heretofore to establish such a control by a motor control relay which is energized over an operating circuit governed by trafiic on the approach section to effect the raising of the gates when a train vacates an approach section, and which relay is provided with a stick circuit to continue the raising of the gates if another train should enter an approach section before the gates have reached their vertical position. My invention constitutes an improvement upon such control by providing means for assuming that should the gates stall in some intermediate position due for example to low battery voltage while the motor control relay is energized over its stick circuit, with the position of the gates such as to indicate a clear track to the motorist although a second train is approaching the crossing, the gates will be lowered from the intermediate position in which they have stalled to the horizontal position to protect the crossing for the second train.

It is an object of my invention therefore to provide a novel and improved system of the type described arranged to provide protection for the crossing should the gates stall in some intermediate position while the motor control relay is energized in its stick circuit.

It is a further object of my invention to provide a novel and improved system of the described type having means nited States Patent for interrupting the stick circuit of the control relay while a second train occupies an approach section if more than a predetermined period of time is consumed in raising the gates from an obstructing to a non-obstructing position.

Other important objects and characteristic features of my invention will become apparent from the following description.

In attaining the above mentioned and other objects of my invention, 1 provide a relay contact in the stick circuit of the motor control relay and means for controlling that contact in such a manner that the contact, although normally open will be closed while the gates are being raised from an obstructing to a non-obstructing position, unless more than a predetermined period of time is consumed in their raising, in which event the contact will be opened at the end of such predetermined period. If the motor control relay is energized over its stick circuit and the gates stall in some intermediate position the contact is effective at the end of said predetermined period to open the stick circuit thereby deenergizing the motor control relay and causing the gates to lower to their obstructing position.

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

The accompanying drawing is a diagrammatic view illustrating one form of apparatus embodying my invention.

Referring to the drawing, the reference characters G1 and G2 designate highway crossing gates located at the intersection of a railway with a highway H. Each gate has a gate arm biased to a horizontal or obstructing position in which it obstructs highway traffic and each has an operating mechanism effective to operate the arm to a vertical or non-obstructing position in which the arm clears the highway.

The operating mechanism of each gate may be of any suitable type of signal actuating mechanism such as that shown and described in Letters Patent of the United States, No. 1,l38,087, granted to John P. Coleman on May 4, 1915. Since the operating mechanisms of both gates may be alike only the mechanism for gate G1 is represented in the drawing which mechanism comprises a motor M operatively connected with the gate to operate it from its horizontal or obstructing position to its vertical or non-obstructing position; a slot magnet SM to hold or latch the gate in its vertical position; and a circuit controller J operatively connected with the gate and having contacts selectively closed in accordance with the position of the gate. In the following description the horizontal or obstructing position of the gate arm will be considered as the 0 position and the vertical ornon-obstructing position will be considered as the position.

The gates are also provided with suitable warning devices such as a bell 60 and lamps 61, and although only two lamps have been illustrated it is to be understood that any desired number may be provided mounted on a pole, gate arm or wherever desired and that the lamps may be flashed in the customary manner. It is to be understood also that the slot magnet SM may in accordance with the usual practice be provided with a pick up winding and a holding winding which windings are suitably controlled to respectively latch and to hold the gate arm in position, and that the motor M may be provided with a snubbing circuit to brake or retard the descent of the gate arm when lowered in response to its bias. Such details however constitute no part of my present invention and have been omitted from the drawing for the purpose of simplifying the description.

The control of the gate operating mechanisms is ,such that with the gate arms in their vertical or non-obstructing position they are caused to descend to their horizontal or obstructing position after a preliminary warning period when a train traveling toward the intersection enters an approach section at a predetermined distance from the intersection and are caused to resume their vertical position when the train vacates the crossing. In case my invention is employed on a multiple track railway such as that shown in the drawing where the reference character X designates one track and the reference character Y designates another track, each track may for thepurpose of controlling the gate arms in the desired manner be divided into a plurality of successive adjoining track sections. Thus, track X may as shown be divided by insulated joints I into sections 2AT, 2ST and 2C1, and similarly track Y may be divided into sections lAT, IBT and ICT. Each section in tracks X and Y is provided with a closed track circuit including a suitable source of current (not shown) and a track relay, the track relay for each section being designated by the reference character R with a prefix corresponding to the reference character of its associated section and the association of each relay with its section being indicated conventionally in the drawing by means of dotted lines.

Tracks X and Y may each be provided with directional control means to accommodate trafiic upon each such track moving in either direction. Such directional control is here obtained by a pair of directional stick relays ESR and WSR for each track X and Y which relays are conventionally controlled by circuits arranged in a manner hereinafter explained, so that the eastbound stick relay ESR of a pair is picked up when an eastbound train enters the aproach section of the track with which that pair of relays is associated, is provided with a first stick circuit when that train occupies the crossing section of track, and with a second stick circuit completed when the train vacates the approach section and occupies the section on the receding side of the intersection: while the other -or westbounddirectional stick relay WSR of a pair is picked up when a westbound train enters the section in aproach to the crossing on the track associated with that pair of relays, is provided with a first stick circuit when that westbound train occupies the crossing section, and with a second stick circuit when the train vacates the approach section and occupies the section on the receding side of the crossing.

The reference character XR designates a control relay having a nor-nal energizing circuit including in series front contacts of each of the several track relays R. Each of the directional stick relays ESR and WSR of a pair when picked up provides an alternate path around the contact of the track relay for the receding section of track (associated with that pair of stick relays) in the circuit for relay XR to provide a directional control of the crossing gates.

The reference character GDR designates a slow release relay provided with an energizing circuit controlled by contact -41 (closed 8693) of controller I and by front contact 42 of relay XR. Relay GDR is provided with a snubbing circuit, obvious from an inspection of the drawing, which circuit includes back contact 42 of relay XR. Relays XR and GDR cooperate in the control of the gate operating mechanism as will be made clear hereinafter.

Operation of the gate motor is governed by a motor control relay MCR provided with an operating circuit and a stick circuit. The operating circuit of relay MCR as shown consists of alternate paths one of which extends from one terminal B of a suitable source of current, such as a battery not shown, over front contact 46 of relay XR through the winding of relay MCR to the other terminal C of the source of current; and the other of which extends from terminal B over front contact of relay GDR through the winding of relay MCR to terminal C. As will be made clear hereinafter, after the gates have been lowered following the entrance of a train upon an approach section and when that train has vacated the intersection,- relay MCR and its operating circuit is effective to cause the gates to be raised to their vertical position.

The stick circuit for relay MCR as shown includes back contact 47 of relay XR, contact 48-49 (closed l093) of controller I, contact 5051 (closed 0-89) of controller I, back contact 52 of relay GDR, front contact 53 of relay MCR and front contact 54 of relay GCR. As will be shown presently, in the event the gates are being raised and a train enters an approach section before'.the gates have reached their vertical position, relay MCR and its stick circuit are effective to continue the operation of the gates to their vertical position before descending, and thus prevent their being lowered from some intermediate position, provided only that in such event not more than a predetermined period of time is consumed in raising the gates to their vertical position. If more than said predetermined period of time is consumed in raising the gates due for example to their stalling in some intermediate position, the stick circuit for relay MCR is opened at front contact 54 of relay GCR and the gates descend to their horizontal position.

To provide for the lowering of the gates in the event of stalling, the energizing circuit of relay GCR may be extended over suitable contacts of the circuit controller I which contacts are closed only in their horizontal or near horizontal position, and relay GCR may be adapted to release 'only at the end of a predetermined period after being deenergized, which predetermined period is preferably approximately equal to the time required to raise the gates from their horizontal or near horizontal position to their vertical position in the absence of stalling. The energizing circuit for relay GCR is, as shown in the drawing, extended over contact 43-44 (closed Ol0) of controller J, and relay GCR has a resistor E and a condenser Q connected in series across its terminals to obtain the desired release period so that although relay GCR will be energized only while the gate arm is in its horizontal or near horizontal position (from 0-l0), it will remain picked up after the gate arm is raised above its 10 position, and will be released at the end of its slow release period to open its contact 54 in the previously traced stick circuit for relay MCR.

The warning bell 60 is controlled over'an obvious circuit which includes back contact 47 of relay XR and contact 48-49 (closed l093) of controller I, and the lamps 61 are controlled over a circuit having alternate paths one of which extends from terminal B over back contact 46 of relay XR through the filaments of lamps 61 in multiple to terminal C and the other of which extends from terminal B, over back contact 55 of relay GDR through the filaments of lamps 61 in multiple to terminal C. The lamp circuits may be controlled by a flasher relay in accordance with the usual practice but such details constitute no part of my present invention and in order to simplify the description the flasher relay and its control of the lamps 61 have been omitted from the drawing. The slot magnet SM and the motor M are energized over obvious circuits, that of slot magnet SM including front contact 55 of relay GDR, and that of motor M including front contact 56 of relay .MCR and contact 57-58 (closed 0 89") of controller I.

In the normal condition of the apparatus as represented in the drawing, each of the various sections of track X and Y is vacant; the track relays are all energized and the directional stick relays all deenergized; relays XR, GDR and MCR are picked up; relay GCR is released; the gates are in their vertical or position; the slot magnet SM is energized to hold gate G1 latched in its vertical position; motor M is deenergized; and the bell 60 and the lamps 61 are deenergized.

I shall now assume that with apparatus embodying my invention in the condition shown in the drawing, a train on track X travelling in an easterly direction, that is, from left to right as viewed in the drawing enters section 2AT whereupon relay 2ATR releases and its front contact 25 opens the normal energizing circuit for relay XR causing relay XR to release. Back contact 11 of relay 2ATR closes to complete a pick-up circuit for relay 2ESR extending from terminal B over front contact 10 of relay 2C1 R, back contact 11 of relay 2ATR and back contact 13 of relay ZWSR through the winding of relay 2ESR to terminal C. Accordingly, relay ZESR picks up and its front contacts 14, 15 and 26 close, front contact 26 of relay 2ESR establishing an alternate path about front contact 27 of relay ZCTR in the normal energizing circuit for relay XR. Front contact 42 of relay XR opens the energizing circuit for relay GDR but back contact 42 of relay XR closes the snub circuit for relay GDR to prevent that relay from releasing for a slow release interval during which the warning devices are operated over back contacts 46 and 47 of relay XR to warn highway users that the gates are about to be lowered. Front contact 46 of relay XR opens one of the alternate paths in the operating circuit for relay MCR, but during the preliminary warning period of operation of bell 60 and lamps 61, relay MCR is held energized over its other alternate circuit controlled by relay GDR. When that relay releases at the end of its slow release interval, front contact 45 of relay GDR opens the other alternate path in the operating circuit for relay MCR, whereupon relay MCR releases and its front contact 56 opens to insure the deenergization of the motor M. Front contact 55 of relay GDR opens to deenergize magnet SM and thereby unlatch the gate arm which has been held in its vertical position by the slot magnet SM .and accordingly the gate arm lowers in response to its bias. Back contact 55 of relay GDR closes one of the alternate paths in the lamp circuit. When the gate arm reaches its position the bell circuit is opened at contact 48-49 (closed 10-93) of controller I ending the operation of the bell. After the arm reaches its horizontal or 0 position it remains there until relay XR picks up.

When the train enters section 2BT relay 2BTR releases and opens its front contact 28 in the previously traced normal energizing circuit of relay XR to insure the continued release of relay XR. Back contact 16 of relay ZBTR closes to complete a first stick circuit for relay ZESR extending from terminal B over back contact 16 of relay 2BTR and front contact 14 of relay 2ESR through the winding of relay 2ESR to terminal C.

Relay 2CTR releases when the train enters section 2CT and front contact 10 of relay ZCTR opens the previously traced pick-up circuit for relay ZESR, but relay ZESR does not release since it is held up over its previously traced first stick circuit. Relay 2CTR closes back contact 10, and opens its front contact 27 in the normal energizing circuit for relay XR.

As the train vacates section 2AT relay 2ATR picks up and its front contact 11 closes a second stick circuit for relay ZESR extending from terminal B over front contact 11 of relay 2ATR, back contact 10 of relay ZCTR and front contact 15 of relay 2ESR through the winding of relay 2ESR to terminal C. Front contact 25 of relay ZATR in the normal energizing circuit for relay XR also closes but that circuit is held open at front contact 28 of relay 2BTR and relay XR therefore remains released.

When the train vacates section 2BT relay 2BTR picks up, and its back contact 16 opens the previously traced first stick circuit for relay 2ESR extending over back contact 16 of relay ZBTR and front contact 14 of relay ZESR. Front contact 28 of relay 2BTR closes an energizing circuit for relay XR extending from terminal B over front contacts 25 of relay 2ATR, 26 of relay 2ESR, 28 of relay 2BTR, 29 of relay lBTR, 31 of relay ICTR and 33 of relay lATR through the winding of relay XR to terminal C. Relay XR now picks up. Back contact 42 of relay XR opens to remove the shunt on relay GDR and front contact 42 of relay XR closes to prepare a circuit for relay GDR. Back contact 46 of relay XR opens one alternate circuit for the lamps 61 and front contact 46 of relay XR closes to effect the energization of the motor control relay MCR. Back contact 47 of relay XR also opens but performs no useful function at this time. Relay MCR picks up to close the energizing circuit for the motor M at front contact 56 of relay MCR and the motor responds to move the gate arm toward its vertical position. When the gate arm reaches its 86 position the energizing circuit for relay GDR closes at contact 40-41 (closed 86-93) of controller I and relay GDR picks up whereupon its back contact 55 opens to deenergize the lamps 61 and its front contact 55 closes completing a circuit for the slot magnet SM thus preparing the slot magnet to latch the gate arm into position when it reaches its vertical or 90 position. Front contact 45 of relay GDR also closes at this time. Contact 57-58 (closed 0-89) of controller I opens to deenergize motor M when the gate reaches its 89 position and the gate drifts to its 90 position.

When the train vacates section 2CI relay ZCTR picks up and back contact 10 of relay 2CTR opens the previously traced second stick circuit for relay 2ESR extending over front contact 11 of relay ZATR and back contact 10 of relay 2CIR. Relay ZESR releases and its front contact 26 opens but relay XR is held energized over front contact 27 of relay 2CT R which contact reestablishes the normal energizing circuit for relay XR when relay 2CTR picks up. Front contacts 14 and 15 of relay 2ESR open and the apparatus is again in its normal condition.

The operation of the apparatus for an eastbound tram on track Y, and for a westbound train on either track X or Y, is believed to be obvious from the foregoing description taken in connection with an inspection of the drawing, it being noted thatrelay IESR will be picked up to provide directional control for an eastbound train on track Y, while relay ZWSR or IWSR, as the case may be, will be picked up to provide directional control for a westbound train on track X or Y, respectively. A detailed description of the operation of the apparatus for these train movements is therefore believed to be unnecessary.

I shall assume now that the gates are being raised after a train has vacated section 2BT on track X as described above and that at this time another train travelling in a westerly direction enters section IAT on track Y-. I shall assume also that the gates have at this time been raised to at least their 10 position but have not yet reached their 86 position and that the eastbound train still occupies section 2CT. Under the foregoing conditions track relays 2ATR and ZBTR are picked up but track relay ZCTR is released. Relay 2ESR is held up over its previously traced second stick circuit extending over front contact 11 of relay 2ATR, back contact 10 of relay 2CTR and from contact 15 of relay ZESR, but the other directional stick relays are all released. Relay XR is energized over the previously traced energizing circuit for that relay including front contact 26 of relay ZESR. Relay GDR is released since under the assumed conditions its energizing circuit is open at contact 4041 (closed 86-93) of controller J. Relay GCR is deenergized since contact 4344 (closed 0l0) of controller I is open, but relay GCR is nevertheless held up because of the slow release features associated with it. Relay MCR is energized over front contact 46 of relay XR and the motor M is energized over front contact 56 of relay MCR and contact 5758 (closed 089) of controller J.

As the westbound train on track Y enters section lAT relay lATR releases and its back contact 17 closes a pickup circuit for relay IWSR extending over front contact 18 of relay ICTR, back contact 17 of relay lATR and back contact 22 of relay lESR. Relay IWSR picks up and its front contacts 19, 20 and 30 close. Front contact 33 of relay IATR opens to deenergize relay XR and relay XR releases. Front contact 46 of relay XR opens the operating circuit for relay MCR but the resistor snub associated with relay MCR prevents that relay from immediately releasing. Before relay MCR can release back contact 47 of relay XR closes the stick circuit for relay MCR extending from terminal B over back contact 47 of relay XR, contact 4849 (closed l093) of controller I, contact 5051 (closed 0-89) of controller I,

back contact 52 of relay GDR, front contact 53 of relay MCR and front contact 54 of relay GCR through the winding of relay MCR to terminal C. This stick circuit maintains relay MCR energized so that its front contact 56 remains closed and motor M remains energized to continue the raising of the gates to their vertical position. It is to be noted that the stick circuit for relay MCR would not close at back contact 47 of relay XR with the gates between their 0 and 10 position, but would re main open at contact 4849 (closed l093) of controller J to permit relay MCR to release and its front contact 56 to open the energizing circuit for motor M thereby permitting the gates to drop to their horizontal position, it being understood that with the gates between their 0 and their 10 position they sufficiently block trafiic on the highway as to permit the gates to be restored immediately to their full-down position without danger of dropping on vehicles at the crossing.

While the gates are being raised under the conditions assumed, the bell 60 is operated over back contact 47 of relay XR and contact 4849 (closed 10-93) of controller J, to warn users of the highway of the approach of a second train. When the gate arm reaches its 89 position, the stick circuit for relay MCR opens at contact 50-51 (closed 089) of controller J to deenergize relay MCR and the motor M. The gate arm therefore lowers in response to its bias thereby protecting the cross ing for the second train. When the gate arm reaches its 10 position, the bell circuit is opened at contacts 4849 (closed 10-93) of controller I ending its operation. As the westbound train travelling on track Y proceeds through sections lBT and ICT the equipment operates in a manner similar to that already described for an eastbound train on track X travelling through sections ZBT and ZAT, to retain these gates in their lowered position until the train clears section lBT, whereupon the gates are raised to their non-obstructing position.

It is of course obvious that the apparatus will operate in a correspondingly similar manner to provide a stick circuit for relay MCR when the gates are being raised following a train vacating either section lBT or 213T and while that train occuplies the track section on the receding side of the intersection, if another train approaching the intersection should enter any of the other outer sectlons (lAT, ICT, 2AT or 2C1). It is therefore believed unnecessary to describe these Operations in detail at this point.

If the gates are being raised following the exit of a train from either section IBT of track Y or 2131 of track X, and while that train occupies the section of track on the receding side of the intersection another train should enter any of the other outer track sections (1AT, ICT, .ZAT or 2C1) in approaching the intersection and low battery voltage or some other cause should result in the gates stalling in some intermediate position, relay GCR will become effective to bring about the release of relay MCR and the gates will be lowered to an obstructing position. Relay GCR becomes deenergized when the gate arm is raised beyond its 10 position since its energizing circuit is open at contact 43-44 (closed -10) of controller I, but relay GCR releases only after a predetermined period which is approximately equal to the time required in normal operation to raise the gate arm from its position to its vertical or 90 position, and in the absence of stalling its front contact 54 therefore remains closed to permit relay MCR to be energized over its stick circuit and the gates to be raised to their vertical position. If the gates stall in an intermediate position, however, the gate control relay GCR releases at the end of said predetermined period to open the stick circuit for relay MCR at front contact 54 of relay GCR whereupon relay MCR releases to deenergize the motor M and the gates lower to their horizontal position.

From the foregoing description it is apparent that if more than a predetermined period of time is consumed in raising the gates when a train occupies an approach section while the gates are being raised to their non-obstructing position, relay GCR will release at the end of such predetermined period to open the stick circuit of the motor control relay. When the stick circuit of the motor control relay opens, the motor control relay releases to deenergize the gate motor and the gates lower from their stalled position to their horizontal or obstructing position. The highway crossing is therefore protected against the possibility of the gates sticking in some intermediate position to indicate a clear track'to the highway user while a second train is bearing down on the intersection.

Although I have illustrated and described only one form of highway crossing signal control system embodying the features of my invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. I n combination, a stretch of railway track intersected at grade by a highway, an approach section in said track streach, a highway crossing gate at the intersection, means responsive to tratfic conditions in said section, motor means operably connected to the crossing gate to operate the gate from an obstructing to a non-obstructing position, a motor control relay having an operating circuit controlled by said traflic responsive means, another circuit for said motor control relay including in series a front contact of that relay and a first contact closed only when said approach section is occupied and a second contact closed while the gate is raised from its obstructing to its non-obstructing position provided the gate reaches its non-obstructing position in less than a predetermined period of time, means for controlling said second contact, and a control circuit for said motor means including a contact of said motor control relay.

2. In combination, a stretch of railway track intersected at grade by a highway, an approach section in said track stretch, a highway crossing gate at the intersection, means responsive to traffic conditions in said section, a motor operably connected to the crossing gate to operate the gate from an obstructing to a non-obstructing position, a controller contact operatively connected with said crossing gate, a motor control relay having an operating circuit controlled by said traffic responsive means, another circuit for said motor control relay including in series a front contact of that relay and a first contact of said means closed only when said approach section is occupied and a second contact closed while the gate is raised from its obstructing to its non-obstructing position provided the gate reaches its non-obstructing position in less than a predetermined period Of time, a gate controlled relay to control said second contact, a control circuit for said gate controlled relay including said controller contact, and a control circuit for said motor including a contact of said motor control relay.

3. In combination, a stretch of railway track intersected at grade by a highway, an approach section in said track stretch, a highway crossing gate at the intersection, means responsive to trafiic conditions in said section, a motor operably connected to the crossing gate to operate the gate from obstructing to a non-obstructing position, a controller contact operatively connected with said crossing gate and closed between predetermined limits of travel of the gate, a gate controlled relay adapted to release only at the end of a predetermined interval after being deenergized, an energizing circuit for said gate controlled relay including said controller contact, a motor control relay having an operating circuit controlled by said. trafiic responsive means, another circuit for said motor control relay including in series a front contact of that relay and a contact of said means closed only when said approach section is occupied and a contact of said gate controlled relay, and a control circuit for said motor including a contact of said motor control relay.

4. In combination, a stretch of railway track intersected at grade by a highway, an approach section in said track stretch, a highway crossing gate at the intersection, means responsive to trafiic conditions in said section, an electric motor operably connected to the crossing gate to operate the gate from an obstructing to a non-obstructing position, a controller contact operably connected with said crossing gate and closed between predetermined limits of the are of travel of the gate, a motor control relay having an operating circuit con trolled by said trafiic responsive means, another circuit for said motor control relay including in series a front contact of that relay and a first contact of said means closed only when said approach section is occup ed and a second contact closed while the gate is raised'from its obstructing to its non-obstructing position provided the gate reaches its non-obstructing position in less than a predetermined period of time, a gate c ntrolled relay to control said A second contact, a condenser connected across the terminals of said gate control relav. an energizing circuit for said gate controlled relav including said controller contact. and an energizing circuit for said electric motor including a contact of said motor-control relay.

5. In combination. a stretch of railway track intersected at grade by a highway. having a first and a second section in said stretch. a track circuit incl ding a track relay for each of said first and second sections. a hi hway crossing gate at the intersection, a motor means noeratively connected to the crossing ate to operate the gate from an obstructing to a non-obstructing osition, a controller contact o eratively connected wi h said crossing gate and closed between predetermined limits of travel of the gate, a gate controlled relav adapted to release only at the end of a predetermined interval after being deenergized, an energizing circuit for said gate controlled relay including said controller contact, a control relay having a energizing circuit controlled bv said track relays. a motor control relay havin a control circuit controlled by said control relav. another circiut for said motor control relay closed only when said control relay is released and including a front contact of said motor control relay and a contact of said gate controlled relay, and a control circuit for said motor means including a contact of said motor control relay.

6. In combination, a multiple track stretch of railway intersected at grade by a highway, each track of said stretch being provided with a first section and an adjoining second section including the intersection. a track circuit including a track relay for each of said first and second sections, a highway crossing gate at the intersection, a motor means ooerativelv connected to the crossing gate to operate the gate from an obstructing to a non-obstructing position, a controller contact operatively connected with said crossing gate and closed between predetermined limits of travel of the gate, a gate controlled relay adapted to release only at the end of a pre determined interval after being deenergized, an energizing circuit for said gate controlled relay including said controller contact, a control relay having an energy circuit controlled by said track relays. a motor control relay having a control circuit controlled by said control 9 relay, another circuit for said motor control relay closed only when said control relay is released and including a front contact of said motor control relay and a contact of said gate controlled relay, and a control circuit for said motor means including a contact of said motor control relay.

7. In combination with a stretch of railway track intersected at grade by a highway and provided with a crossing section including the intersection and two outer sections one on either side of and adjoining said crossing section, a track circuit including a track relay for each of said sections, directional control means controlled by said track relays, a highway crossing gate at the intersection, a motor means operatively connected to the crossing gate to operate the gate from an obstructing to a non'obstructing position, a controller contact operatively connected with said crossing gate and closed between predetermined limits of travel of the gate, a gate controlled relay adapted to release only at the end of a predetermined interval after being deenergized, an energizing circuit for said gate controlled relay including said controller contact, a control relay, a control circuit for said control relay governed by said track relays and by said directional control means so as to be completed at all times except when a train occupies said crossing section or approaches the intersection and occupies an outer section, a motor control relay having a control circuit controlled by said control relay, another circuit for said motor control relay closed only when said control relay is released and including a front contact of said motor control relay and a contact of said gate controlled relay, and a control circuit for said motor means including a contact of said motor control relay.

8. In combination, with a multiple track stretch of railway intersected at grade by a highway, each track of said stretch being provided with a crossing section including said intersection and two outer sections one on either side of and adjoining said crossing section, a track circuit including a track relay for each of said sections, directional control means for each of said tracks and controlled by the associated track relays, a highway crossing gate at the intersection, a motor means operatively connected to the crossing gate to operate the gate from an obstructing to a non-obstructing position, a controller contact operatively connected with said crossing gate and closed between predetermined limits of travel of the gate, a gate controlled relay adapted to release only at the end of a predetermined interval after being deenergized, an energizing circuit for said gate controlled relay including said controller contact, a control relay, a control circuit for said control relay governed by said track relays and by said directional control means so as to be completed at all times except when a train occupies a crossing section or approaches the intersection and occupies an outer section of track, a motor control relay having a control circuit controlled by said control relay, another circuit for said motor control relay closed only when said control relay is released and including a front contact of said motor control relayand a contact of said gate controlled relay, and a control circuit for said motor means including a contact of said motor control relay.

References Cited in the file of this patent UNITED STATES PATENTS cane?!-

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