US2647988A - Apparatus for controlling highway crossing signals - Google Patents

Description

4, 1953 w. H. CLAUS 2,647,988

APPARATUS FOR CONTROLLING HIGHWAY CROSSING SIGNALS Filed March 25, 1950 INVEN TOR.

111s arromvz Patented Aug. 4, 1953 OFFICE APPARATUS FOR CONTROLLING HIGHWAY CROSSING SIGNALS William H. Claus, Downers Grove, Ill., assignor to Westinghouse Air B ration of Pennsylvania Application March 23, 1950, Serial No. 151,383

2 Claims.

My invention relates to apparatus for controlling highway crossing signals, and particularly to apparatus for interrupting the operation of a highway crossing signal when a train which is approaching an intersection stops or delays in a particular control section of track, and for then restarting the signals when the train resumes its movement toward the crossing. More particularly my invention relates to apparatus of the above described type which may be used equally well with 01' without wayside signals.

In a highway crossing signal control system employing track circuits, the signals are usually set into operation when a train enters the approach section of track and are operated for not less than a predetermined time interval such as twenty seconds before the train arrives at the intersection. If the signals are to be operated for a period of not less than twenty seconds the approach section must then have a length equal to or greater than the distance traversed in twenty seconds by a train operating at a maximum authorized speed; However, it sometimes happens that trains will stop or slow down in the approach section, as at'a station before reaching the intersection, and as a result the signals are operated continuously while the slow moving or stopped trains occupy this'section. In such events highway traflic is unnecessarily restricted at the intersection and highway users may come to disregardthe signals altoether'.

I propose to provide a system which will interrupt the operation of the highway crossing signals when a train stops or delays in the approach section. In my system the stretch in approach to the intersection is divided into plurality of sections, a starting section, a timing section and a positive operating section, and apparatus is provided to initiate operation of the signals when a train enters the starting section, to interrupt their operation if the train should occupy the timing section for longer than a predetermined time, and to restart their operation if previously interrupted or to continue operation if not interrupted when the train enters the positive operating section.

Highway crossing signal control systems heretofore known in the art which are adapted to accommodate slow moving or stopped trains in the approach section generally utilize the release of a track relay to set into operation a timing device which at the end of a predetermined time interval is efiective to cut out or otherwise modify th operationoi the crossing take Company, a corposignals. When used in conjunction with wayside signals, a protective check upon the integrity of the track circuit used in the control of the timing device is incorporated into such a system for the wayside signals are controlled by track circuits, and in the event the integrity of the track circuit for the timing device is impaired the wayside signals will restrict the train speed sufficiently to provide an adequate interval of operation of the crossing signals after the train enters the positive operating section. Such a protective check is generally not available, however, when a system of this type is used on a stretch of track which is not equipped with Wayside signals.

Itis an object of my invention to provide a novel and improved highway crossing signal control system of the type described which is adapted for use equally well with or without wayside signals.

Another object of my invention is the provision of a novel and improved highway crossing signal control system of the type described which incorporates means for checking the integrity of the track section used in the control of the timing device.

A further object of my invention is the provision of a novel and improved system which will establish control'over a timing device only if the track circuit which controls the device is intact.

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

To obtain the above mentioned and other objects of my invention, I provide a polarized track circuit for the timing section and control the polarity of energization of that circuit so as to energize it by current of one polarity when the starting section is vacant and by current of the other polarity when the starting section is 00- cupied. The track relay for the timing section is utilized to control an operating relay, and to control a timing relay if the polar contacts of the track relay have responded to a reversal of polarity in the track circuit. The timing relay when operated is effective to cut out the control of the operating relay by the track relay of the timing section.

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 showing one form of apparatus embodying my invention.

Referring now to the drawing, reference charother side of the crossing.

acters la and lb designate the rails of a given stretch of track which is intersected at grade by a highway H. Highway crossing signals, designated by the reference characters XS, which may take any one of a number of suitable forms, but which are for the sake of simplicity shown as bells, are located adjacent the intersection. These signals are controlled by an operating relay which, as shown, may comprise one winding or the other of an interlocking relay XR.

Interlocking relay XR is characterized by the provision of two windings 2| and 22 and a mechanical locking arrangement controlled by the armatures of the two windings in such a manner that with both armatures picked up the release of either armature latches up the other armature to prevent it from closing its back contacts if it should release before the first armature is picked up. Thus, for example, when the armature of winding 2| is the first to be '6- leased, back contact l9 associated with it close and the armature of winding 22 is latched up so that when winding 22 subsequently becomes deenergized with winding 2| still released, back contact operated by winding 22 is prevented from closing. A relay of this type is shown for example in Letters Patent of the United States No. 1,799,629, granted April '7, 1931, to W. K. Lockhart and T. J. OMeara.

Insulated joints designated by the reference character 2 divide the track into a plurality of successive adjoining sections, a preliminary starting section AT, a timing section BT and an absolute operating section CT all of which lie to one side of the intersection as shown, and another section DT, which is located on the Each such section is provided with a track circuit comprising a track battery 3 and a track relay connected respectively to the rails at the opposite ends of the section. The track relays for sections AT, B'I, CT and DT are designated by the reference characters ATR, BPTR, CTR and DTR, respectively.

Track relays ATR, CTR and D'I'R are neutral relays each normally maintained in an energized state, but shunted by the presence of a train in the section with which it is associated. Relay BP'I'R, however, is a polarized relay of the retained neutral polarized type, characterized by the provision of means for retaining its neutral contacts picked up during reversal of polarity of current in its operating winding. A relay of this type is shown and described in Letters Patent No. 1,852,210 for Polarized Relay, issued April 5, 1932 to Frederick C. Larson. The battery 3 of the track circuit for section ET is connected with the rails of the section over front contacts it and H' of relay ATR when that relay is picked up, and over back contacts in and H when that relay is released, with the arrangement being such, as is obvious from an inspection of the drawing, that relay BPTR is supplied with energy of one polarity when relay ATR is picked up, and with energy of the opposite polarity when relay ATR is released, and as a result the energization of relay BPTR is pole changed whenever relay ATR shifts its position.

One winding 2| of interlocking relay KR is normally energized over a circuit which includes a front contact i2 of relay BPTR, a polar contact l3 of relay BPTR closed in its normal or left hand position as viewed in the drawing, a front contact H of relay CTR, and a suitable source of current such as a battery not shown,

4 the terminals of which are designated as B and C in the drawing. The other Winding 22 of interlocking relay XR is energized over an obvious circuit including a front contact l8 of relay DTR.

Polarized relay BPTR also controls the operation of a time element relay TER Over a circuit including a back contact l4 and a polar contact l5 of relay BPTR closed in the reverse or right hand position as viewed in the drawing. Time element relay TER may be of any suitable type arranged so that it will pick up and close its front contact It only after the completion of an operating cycle which requires the relay to be energized for a predetermined period of time. Relay TER. may, for example, be of the oscillating armature type shown and described in Patent No. 1,966,965, entitled Electrical Relay, issued July 17, 1934, to Brancho Lazich and H. E. Ashworth. When front contact it of relay TER closes, an alternate energizing circuit is provided for winding 2| of interlocking relay XR, which circuit includes front contact l6 of relay TER and front contact ll of rela CTR.

The three successive adjoining track sections AT, BT and CT taken together extend to one side of the intersection a distance at least equal to that which would be traversed in 20 seconds by a train operating at the highest authorized speed for the stretch. The crossing signals are set into operation as will be made clear hereinafter when an eastbound train, that is, a train operating from left to right as viewed in the drawing, enters section AT. As a result the crossing signals are set into operation for a period of not less than 20 seconds before a train moving at the maximum authorized speed reaches the intersection. Section CT extends to one side of the intersection a distance equal to that traversed in 20 seconds by a relatively slow speed train moving, for example, at not more than 15 miles per hour. Sections AT and BT may have any relative lengths within the limits indicated above but preferably section AT is relatively short with respect to the length of section B'I. It will be assumed that section BT includes a water tank, station, etc., at which some, but not all eastbound trains will stop. Section DT on the opposite side of the intersection, may have any desired length which may, for example, be equal to the combined lengths of sections AT. BT and CT.

The apparatus embodying my invention is illustrated in the drawing in its normal condition, that is, in the condition which normally obtains when each of the several track sections is unoccupied. In this condition of the apparatus the track relays are picked up with relay BP'I'R energized by current of normal polarity so that its polar contacts occupy their normal or left-hand position; both windings of the interlocking relay XR are energized so that the crossing signals are inactive; and timing relay TER is deenergized.

I shall now assume an section AT while moving toward the intersection at relatively high speed. When this train enters starting section AT, the shunting action of its wheels and axles deprives track relay ATR of current. Its armature releases and its back contacts l0 and ii close while its front contacts I0 and il open. The polarity of the current energizing relay BPTR is now reversed and in consequence normal polar contact I3 opens and reverse polar contact |5 closes. When normal polar contact i3 opens it opens the normal energizing eastbound train enters circuit for winding 2| of interlocking relay xa, which circuit extends from terminal B over front contact |2 of relay BPTR, normal polar contact [3 of relay BPTR and front contact I! of relay CTR through winding 2| of relay XR to terminal C. Back contact l9 of winding 2| then closes completing an energizing circuit for signals XS: extending from terminal B over back contact l9 through signals XS to terminal C, and the signals are set into operation. Reverse polar contact l5 in closing prepares the previously traced circuit for relay TER, and checks the integrity of the track circuit for section BT as will be pointed out hereinafter.

When this train, moving at relatively high speed enters section BT, it causes relay BPTR to open its front contact I2 in the previously traced normal energizing circuit for winding 2|. Front contact I2 performs no useful function at this time but is provided to insure proper operation for westbound traffic as will be made clear hereinafter. The release of relay BPTR also causes its back contact M to close and it completes the energizing circuit for relay TER extending from terminal B over back contact l4 and reverse polar contact l5 of relay BPTR through relay TER to terminal C. Time element relay TER is set to have an operating cycle such that it will pick up only after being energized for a predetermined period, which is substantially longer than that required for a train to travel section BT at any substantial speed. Under the conditions assumed, the train will travel the length of section BT and enter section CT before relay TER picks up. Relay TER will be energized as long as section ET is occupied but this action has no useful function under the assumed conditions.

Upon entering section CT the armature of track relay CTR is released opening its front contact IT. The normal energizing circuit for winding 2| of relay XR is open at front contact l2 of relay BPTR, normal polar contact |3 of relay BPTR and front contact I! of relay CTR. Winding 2| is therefore held released and back contact IQ of winding 2| is held closed to continue the operation of the signals. Front contact I! of relay CTR remains open during occupancy of section CT to maintain the signals in operation after the train has vacated sections AT and BT causing front contact l2 and normal polar contact 3 of rela BPTR to close as will be explained hereinafter.

When the train enters section DT on the opposite side of the crossing the armature of track relay DTR releases to open the circuit energizing Winding 22 of relay XR which circuit extends from terminal B over front contact l8 of relay DTR through winding 22 to terminal C. The armature of winding 22 is released, but its back contact 20 is latched up by the mechanical locking feature of interlocking relay XR already referred to and it does not close.

Now, as the train vacates section AT the armature of relay ATR is picked up closing front contacts I0 and H to supply current of normal polarity to the rails of section BT. Relay BPTR is however still shunted by the train in section BT, and as a result the energizing circuit for relay TER is held closed. Relay TER may complete its operating cycle and close its front con tact it but this action will have no effect at this time because both the normal and alternate circuits for winding 2| are held open atfront contact ll of relay CTR.

When the train vacates section BT, relay BPTR becomes energized by current of normal polarity,

so that front contact l2 and normal polar contact l3 of relay BPTR close to prepare the normal energizing circuit for winding 2| of interlocking relay XR but that circuit is still maintained open over front contact I! of relay CTR. As a result, contact I9 of winding 2| remains closed and the signals continue to operate. Back contact M and reverse polar contact l5 of relay BPTR are now open to deenergize relay TER and if that relay is picked up, it releases to open its front contact 6.

The signals cease to operate only when the train vacates section CT. At this time relay CTR picks up closing its front contact H to complete the previously traced normal energizing circuit for winding 2|. Front contact IQ of winding 2| opens and operation of the signals is discontinued.

As the train vacates section DT relay DTR picks up closing its front contact 8. Winding 22 of interlocking relay XR becomes energized and back contact 20 is brought from its latched up position to its energized position restoring the apparatus to normal.

I shall now describe the manner in which my invention operates for an eastbound train whichtravels toward the intersection and which stops or slows down in section BT so that the time taken for the train to travel across that section is greater than the interval required for relay TER to pick up after being first energized. Upon the train entering section AT, relay BPTR is pole changed in the manner described heretofore. Its normal polar contact |3 opens to open the previously traced normal energizing circuit for winding 2|, while its reverse polar contact l5 closes to prepare the circuit for relay TER. Contact IQ of winding 2| thereupon closes and the signals XS are set into operation. I I

When the train enter section BT it causes front contact 2 of relay BPTR to open and back contact M of relay BPTR to close. Relay TER is then energized over its circuit including back contact l4 and reverse polar contact I5 of relay BPTR. Under the conditions assumed relay TER will pick up before the train traverses section BT. Contact l6 of relay TER will therefore close and the previously mentioned alternate energizing circuit for winding 2| of interlocking relay XR, will be completed, which circuit extends from terminal B over front contact H; of relay TER and front contact H of relay CTR through winding 2| to terminal C. Back contact I9 of winding 2| will open and as a result operation of the highway crossing signals XS will be discontinued.

Operation of the signals XS will therefore be discontinued for a train which stops in section BT, or proceeds so slowly in that section that continued operations for such a train is undesirable. The crossing signals will not be operated under the conditions assumed, until the train resumes 01 continues its movement toward the crossing and enters section OT. A train under these conditions will be moving at such a low rate of speed that an adequate period of warning will be provided highway user before the train reaches the crossing, and the operation of the signals which is effected when the train enters section CT to shunt relay CTR and cause it to open its front contact I! in the alternate energizing circuit of winding 2|, therefore, will provide adequate protection for highway users.

Further operation of the system in response to the train proceeding into section DT, and vacating the variou track sections, results in restoring the system to its normal condition. The manner in which this occurs is the same as that already described for a train travelling through the intersection at relatively high speed and need not be repeated.

I shall now assume that with all parts of the apparatus again in their normal condition, a westbound train enters section DT, causing the deenergization of relay DTR which in turn brings about the deenergization of winding 22 of relay XR. Back contact 20 of winding 22 closes and the signals are set into operation.

When the train enters section CT relay CTR is deenergized and its front contact I1 is opened. Although the normal energizing circuit for winding 2| of relay XR is then open at front contact i1, back contact IQ of winding 2| is prevented from closing by the interlocking feature of relay XR.

Occupancy of section BT causes relay BPTR. to open its front contact l2 and close its back contact H. The normal energizing circuit for winding 2| is then maintained open at front contact I2 of relay BP'IR and front contact ll of relay CTR. Back contact M of relay BP'I'R performs no useful function at this time but is provided to insure proper operation for eastbound traffic as explained heretofore.

When the train enters section AT it causes back contacts In and II of relay ATR to close in preparation for pole changing relay BPTR which occurs when the train vacates section BT.

Now as this train vacates section DT relay picks up, its front contact I8 closes and winding 22 of interlocking relay XR becomes energized. Contact 20 of winding 22 opens and the signals cease to operate.

When the train vacates ection CT contact H of relay CTR closes. Winding 2| of relay remains deenergized however, for its normal energizing circuit is still open at front contact i2 of I relay BPTR, and back contact IQ of winding 2! remains in its latched up position.

When the train vacates section BT current of reverse polarity is supplied to relay BP'IR so that its normal polar contact l3 opens and reverse polar contact |5 closes. Front contact l2 of relay BPTR also closes and back contact 14 of relay BPTR opens. The normal energizing circuit for winding 2| of relay XR which includes front contact l2 of relay BPTR, normal polar contact l3 of relay BPTR, and front contact I! of relay CTR is held open at normal polar contact l3 of relay BPTR and back contact l9 of winding 2| still remains in its latched up position. Although reverse polar contact l5 of relay BPTR is closed, back contact M of relay BPTR is open and the energizing circuit for time element relay TER which extend from terminal B over back contact ll of relay BPTR, and reverse polar contact l5 of relay BPTR, is held open at back contact 14 and relay TER remains deenergized.

As the train vacates section AT back contacts I0 and H of relay ATR open and front contacts l0 and close to pole change relay BPTR. Normal polar contact l3 of relay BPTR closes and reverse polar contact |5 of relay BPTR opens. The previously traced normal energizing circuit for winding 2| of interlocking relay XR is then closed and winding 2| of relay XR picks up to bring its back contact l9 from it latched up position to its energized position. The apparatus is then once again in its normal condition.

It follows from the foregoing description of the operation of the apparatus shown in the drawing that although my invention will provide continuous operation of the signals for high speed 8, trains and interrupted operation for trains which delay or stop in their approach to the intersection, the system will also detect an impairment in the integrity of the timing section whether or not it is used in conjunction with wayside signals.

If, for example, with the apparatus in its normal condition illustrated and the stretch vacant, the integrity of the track circuit for section BT should become impaired as by a broken rail or bond wire or other cause so that relay BPTR is caused to release, the position of its polar contacts will not be affected. The circuit for timing element relay TER including back contact l4 and polar contact l5 of relay BPTR closed in its reverse position, will be held open at polar contact I5 and as a result relay TER will not be energized and will not be able to close its front contact Hi to complete the alternate energizing circuit for winding 2|. It follows that under the conditions assumed relay TER will not operate to cut out relay BPTR from control of winding 2|, and the operation of the signals initiated upon release of relay BPTR will be maintained until the track circuit is restored. Under these conditions the highway crossing signals will operate continuously so that trains approaching the crossing will have the protection of the crossing signals regardless of the speed of the train, and it is not necessary to rely upon the restriction of the train speed by the wayside signals in order to assure an adequate period of operation of the crossing signals prior to the arrival of the train at the crossing. It is thus apparent that my invention provides a timing circuit which will secure operation of the timing device associated with it only in the event the track circuit which controls the timing device is intact. It is also apparent that a highway signal control system embodying my invention may be provided for a stretch of track whether equipped with wayside signals or not, and that it will avoid cutting out operation of the highway crossing signal by the timing device should a failure occur in the track circuit controlling the timing device.

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:

1. In combination with a stretch of railway track provided with two adjoining track sections, a track circuit including a track relay for each of said sections, the track relay for one of said sections comprising a polarized relay, means controlled by the track relay of the other section for supplying current of one polarity or the other to the track circuit for said one track section according as the other track relay is picked up or released respectively, a time element relay, an energizing circuit for said time element relay including a back neutral and a reverse polar contact of said polarized relay whereby a release of said polarized relay is effective to energize said time element relay only if the polar contacts of said polarized relay have operated to their reverse position in response to supply of current of reverse polarity to the track circuit of said one track section and means controlled by said time element relay.

2. In combination with a stretch of railway track provided with three successive adjoining track sections and intersected by a highway adjacent an outer one of said three sections, a highway crossing signal at such intersection, a track circuit including a track relay for each of said sections, the track relay for the middle one of said three sections comprising a polarized relay having polar contacts operable to normal or reverse positions according as said relay is energized by current of normal or reverse polarity respectively, means controlled by the track relay for the other outer section for supplying current of normal or reverse polarity to the track circuit for said middle section according as the track relay for said other outer section is picked up or released respectively, a time element relay having a contact closed at the expiration of a predetermined period of energization of said relay, an energizing circuit for said time element relay including a back neutral and a reverse polar contact of said polarized relay whereby a release of said polarized relay is effective to energize said time element relay only if the polar contacts of said polarized relay have operated to their re- 10 verse position in response to supply of current of reverse polarity to the track circuit of said middle section, a control relay, 2. normal energizing circuit for said control relay including a front contact of the track relay for said one outer section and a front neutral and a normal polar contact of said polarized relay, an alternate energizing circuit for said control relay including a front contact of the track relay for said one outer section and the closed contact of said time element relay, and means governed by said control relay for controlling said highway crossing signals.

WILLIAM H. CLAUS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,152,276 Pfiasterer Mar. 28, 1936 2,346,518 Tizzard Apr. 11, 1944 2,452,868 Quinlan Nov. 2, 1948

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