US2790895A - Highway crossing protection control apparatus - Google Patents

Description

April 30, 1957 E. J. SCHAEFER HIGHWAY CROSSING PROTECTION CONTROL APPARATUS Filed NOV. 12, 1952 ll! ml.

- IN V EN TOR. Edwin J Scbaefen MAM.

HIS Z47 I HRIVEY' United States Patent HIGHWAY CROSSING PROTECTION CONTROL APPARATUS Edwin J. Schaefer, Wilmington, N. C., assignor to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application November 12, 1952, Serial No. 319,875

6 Claims. (Cl. 246-130) My invention relates to highway crossing protection control apparatus and in particular to a circuit arrangement for protecting against broken rails in the sections approaching a highway crossing in non-signaled territory.

It has been common practice to employ directional stick relays in conjunction with track relays to effect the control of highway crossing signals. These directional stick relays are so controlled that a train entering a track section at one side of a railway-highway crossing energizes one of the stick relays which, when energized, establishes a stick circuit to maintain itself energized while the train moves through the stretch. These directional stick relays also operate when energized to establish a circuit to supply energy to the highway crossing signal control relay when the track section which includes the intersection is vacated, so that the highway crossing signal ceases to operate when the train recedes from the crossing.

Under normal conditions, when the train vacates the section beyond the crossing, that is the receding section, the stick relay is deenergized and the crossing signal is thereafter controlled by the track relays so that the operation of the signal will be initiated on the approach of a second train moving in the same or opposite direction as the first train.

However, with the arrangement heretofore employed, if a rail in the receding section should become broken while a train is moving through that section away from the crossing, the stick relay will remain energized. Thereafter, if a train should approach the crossing from the opposite direction .to the first train, no warning of its approach will be given to highway traffic because, with the stick relay continuously energized, energy will be continuously supplied to the signal control relay, and therefore keep the crossing signal deenergized.

It will be obvious that in territory where wayside or cab signals control train movements, a broken rail condition will cause these signals to display a restrictive aspect. In such territory, therefore, a broken rail will not create the hazardous condition of a train speeding toward highway traflic which is not aware of the approach of the train. However, in non-signaled territory, no indication is given of the broken rail and it is therefore desirable to eliminate the possibility of the hazard existing.

It is an object of my invention to provide improved means of the type described which is so arranged that if a rail in the receding section is broken during a receding move, the crossing signal will still operate for a train moving in the opposite direction to the first train.

A further object of my invention is to provide means of the type described which will prevent an energized directional stick relay from remaining energized if a rail in the receding section should become broken during a receding move from a highway crossing.

According to my invention'l. provide two approach sections and a crossing section each provided with a track circuit including a track relay. I further provide 2,790,895 Patented Apr. 30, 1957 ice a directional stick relay, one associated with each approach section. Each of the approach track circuits includes a back contact of the associated stick relay. In addition to the ordinary stick circuit for sticking up the directional stick relay while the train or vehicle occupies the crossing section, I provide a stick circuit which is closed only if the rails of the receding section are shunted by the wheels and axles of a receding train. If one of the rails in the receding section becomes broken, after the rear wheels of the vehicle pass over the break, the stick circuit will become open and the stick relay will release. The track relay will also be released due to the track circuit being open at the break in the rail. Accordingly, the signal control relay will be deenergized and the crossing signal will operate so as to continuously warn highway trafiic and indicate to maintainers that something is wrong.

Other objects of my invention will appear hereinafter as the characteristic features of construction and mode of operation of my highway crossing protection control apparatus are described in detail.

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

The accompanying drawing is a diagrammatic view of circuit arrangement for the control of highway crossing signals embodying my invention.

Referring now to the drawing, the reference characters 1 and 2 designate the rails of a stretch of railway track over which trafiic moves in both directions. The track rails are divided by insulated joints 3 into two relatively long approach sections IT and 2T, and a short track section XT which is intersected by a highway H. A crossing signal XS is located adjacent the intersection to warn highway traffic of the approach of a train. The crossing signal XS may be of any appropriate type such as a light signal, or as here shown, an electric bell.

Track sections 1T, 2T and X-T are provided with track circuits including track batteries 1TB, 2TB and XT B, respectively, :and track relays 1T R, ZTR and XTR, respectively.

The crossing signal XS is controlled by a signal control relay XR. Signal control relay XR is, in turn, controlled by the track relays and by two directional stick relays 'WSR and ESR in a manner which will be described presently.

The stick relays ESR and WSR are energized separately by batteries B8B and W313, respectively. The purpose of using these separate batteries will become clear from the following description. Energy for control relay XR and the crossing signal XS may be supplied by any sui-table source, for instance, a battery L8.

The apparatus is shown in the condition it normally assumes when the stretch is vacant. At this time the stick relays WSR and ESR are deenergized. Trackrelay iTR is energized by its associated track battery 1TB over back contacts a and 12 of relay WSR and track relay ZTR is energized by its associated track battery 2TB over back contacts a and b of relay ESR. Signal control relay XR is energized by a circuit which may be traced from positive terminal B of battery LB, over front contact b of relay lTR, front contact 0 of relay XTR, front contact I) of relay ZTR, and the winding 'of relay XR to the negative terminal N of battery LB. With relay XR so energized, its back contact a will be open and crossing signal XS will be deenergized.

I will now assume that an eastbound train approaching from the left enters the section, thereby causing relay 1TR to release. When relay 1TR releases, the previously traced circuit for energizing signal control relay XR becomes opened at front contact b of relay lTR, and relay XR will therefore release closing its back contact a. This 3 1 will complete an obvious energizing circuit for crossing signal XS which will commence operating.

When the train enters section X1, the wheels and axles .of the train-will shunt relay XTR, thereby causing it to release, thus closing its back contacts 11 and 1b and .opening its front contact .c. This will cause a pick-up circuit for energizing relay ESR to be established. This .ClICLllll may be traced from the positive terminal .of battery ESB, over back contact I) of relay XTR, back contact a of relay IT'R, back contact .d of relay 'WSR, and the winding of relay ESR to the negative terminal ofbattcry ESB. Upon the energization of relay ESR, a first stick circuit will be established for maintaining relay ESR picked up. This first stick circuit may be traced from the positive terminal of battery ESB, over back contact I; of relay XTR, front contact (I of relay ESR, back contact d of relay WSR, and the winding of relay ESR to the negative terminal of battery ESB. 1T, relay ESR will remain energized by the first stick circuit.

Upon relay XTR releasing, the previously traced energizing circuit for relay XR will become open at front contact of relay XTR. Therefore, as long as the train occupies section XT, relay XR will be released and crossing signal XS will continue to operate. Furthermore, upon relay ESR picking up, track relay ZTR will release, since its energizing circuit will be open at back contacts a and b of relay ESR. Another result of relay ESR picking up is that its back contact c will become open and thus insure against relay WSR becoming energized.

When the train enters section 2T, a second stick circuit for maintaining relay ESR energized will become established. This second stick circuit may be traced from the positive terminal of battery ESB, over front contact a of relay ESR, rail 2 in section 2T, the wheels and axles of the train that are occupying section 2T, rail 1 in section 2T, front contact b of relay ESR, and the winding of relay ESR to the negative terminal of battery ESB. When the train vacates section XT, this second stick circuit will maintain relay ESR picked up.

When the train vacates section XT track relay XTR will pick up and close its front contract c. This will establish a new energizing circuit for relay XR which may be traced from the positive terminal B of battery LB, over front contact 1b of relay lTR, front contact c of relay XTR, front contact of relay ESR, 'and the winding of relay XR to the negative terminal N of battery LB. Relay XR will therefore again pick up, thus causing the circuit which energizes crossing signal XS to become open at back contact a 0f relay XR. Crossing signal XS will accordingly cease operating.

When the train wacates section 2T, the second stick circuit for relay ESR will become open since there is no shunt across the rails, and relay ESR will therefore release. It should be noted that the polarity of battery .ESB opposes the polarity of track battery 2TB and this polarity opposition enables relay ESR to rapidly release and relay ZTR to pick up due to the reestablishment of the original track circuit for section 2T. Upon relay ZTR picking up, the original circuit for energizing relay XR will be reestablished and relay XR will remain energized. Therefore, crossing signal XS will remain deenergized and not operating. In this manner, the original condition of the circuit arrangement will be restored.

It should be obvious from the symmetry of the circuit arrangement that corresponding circuits would be established or closed and correspondingindications would be given highway trafic if .a westbound train should proceed through the stretch from right to left.

Let it now be assumed that after an eastbound train has entered section 2T, 40118 of the rails in section 2T becomes broken. As long as all the wheels of the train have not passed :over the broken rail, the second stick circuit for :stick .relay ESR, which was traced from the positive terminal :of battery ESE, iover front contact a When the train vacates section I of relay ESR, rail 2, the wheels and axles occupying section 2T, rail 1, front contact b of relay ESR, and the winding of relay ESR to the negative terminal of battery ESB, will be closed and relay ESR will remain picked up. However, when all the wheels have passed over the broken rail, this stick circuit will become open at the rail break and relay ESR will release. Upon the release of relay ESR, relay ZTR, which was released, will not pick up because its associated track circuit is also open at the rail break. With both of these relays released. there is no closed circuit for energizing relay XR, and it too will release. With relay XR released, crossing signal XS will become energized and will operate continuously. This continuous ringing will give a positive indication that something is wrong with the circuit arrangement. And furthermore, because of the continuous operation of crossing signal XS, highway traffic will be forewarned of any subsequent westbound moves, and, although the warning period may be appreciably longer than the ordinary warning period, it will be on the safe side.

From the symmetry of the circuit arrangement, it will be apparent that if, during the receding move of a westbound train, a rail in section 1T becomes broken, signal XS will commence continuous operation and afford ample warning to highway trafiic of any subsequent opposing moves.

Although, as I have already pointed out, my invention is particularly useful in non-signaled territory, my invention may be used to good advantage in territory provided with wayside or cab signals, or both.

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

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track divided into a first, a second and a third track section by insulated joints, said third section being between said first and second sections and intersected by a highway, a first, second and third track relays associated with said first, second and third track sections, respectively, a first and a second stick relay associated with said first and second track relays, respectively, said first and second track sections each being provided with a track circuit including its associated track relay and so arranged that the track circuit is open when its associated stick relay is energized, said third section being provided with a track circuit including said third track relay, a highway crossing signal adjacent said intersection, a signal control relay for controlling said highway crossing signal, said signal control relay being controlled by said third track relay and jointly by said first track and stick relays and jointly by said second track and stick relays, each of said stick relays being controlled to become energized when the two track relays not associated with said stick relay are both deenergized, a first stick circuit, one for each stick relay, closed when said third track relay and the other stick relay are both deenergized, and a second stick circuit, one for each stick relay, including the rails of the associated track section and adapted to include the wheels and axles of a train in said associated section.

2. In combination, a stretch of railway track divided into a first, a second and a third .track section by insulated joints, said third section being between said first and second sections and intersected by a highway and said first, second and third track sections having associated therewith a first, a second and a third track relay, respectively; a first and a second stick relay associated with said first and said second track relay, respectively; a first and a second track circuit for energizing said first and second track relays, respectively, each including a back contact of its associated stick relay; said third track section being provided with a track circuit including said third track relay, an energizing circuit means for each stick relay controlled by a back contact of each of the two non-associated track relays and a back contact of the other stick relay, a first stick circuit means for each of said stick relays each controlled by a back contact of said third track relay and a front contact of said stick relay and a back contact of the other stick relay, a second stick circuit means for each of said stick relays each controlled by a, front contact of the stick relay and adapted to include the wheels and axles of a train in the section associated with the stick relay, a highway crossing signal adjacent said intersection, a control relay, circuit means controlled by a back contact of said control relay for energizing said highway crossing signal; and circuit means for energizing said control relay controlled by a front contact of said third track relay and front contacts of said first track and stick relays in multiple, and front contacts of said second track and stick relays in multiple.

3. In combination, a stretch of railway track divided into a first, a second and a third track section by insulated joints, said third section being between said first and second sections and intersected by a highway, first, second and third track relays associated with said first, second and third track sections, respectively, a first and a second stick relay associated with said first and second track relays, respectively, a first and a second track circuit including the associated track relay and being so arranged that when the associated stick relay becomes energized the associated track relay is released, a third track circuit including said third track relay, an energizing circuit means for said first stick relay closed when said second and third track relays are deenergized and said second stick relay is deenergized, a first stick circuit means for said first stick relay closed when said third track relay and said second stick relay are both deenergized, a second stick circuit means for said first stick relay adapted to include the wheels and axles of a vehicle in said first track section, an energizing circuit means for said second stick relay closed when said first and third track relays are deenergized and said first stick relay is deenergized, a first stick circuit means for said second stick relay closed when said third track relay and said first stick relay are both deenergized, a second stick circuit means for said second stick relay adapted to be closed by the presence of wheels and axles of a vehicle in said second track section, a highway crossing signal adjacent said intersection, a control relay for controlling said highway crossing signal, and circuit means for energizing said control relay controlled by said third track relay and jointly by said first track and stick relays and jointly by said second track and stick relays.

4. In combination, a stretch of railway track divided into first, second and third track sections by insulated joints, said third track section being between said first and second track sections and intersected by a highway, said first, second and third track sections each having lassociated therewith first, second and third track relays, respectively, a first and a second stick relay associated with said first and second track relays, respectively, said first and second track sections each being provided with a track circuit including the associated track relay and a black contact of the associated stick relay, said section being provided with a track circuit including said third track relay, an energizing circuit means fior said first stick relay controlled by a back contact of said second track relay and a back contact of said third track relay and a back contact of said second stick relay, a first stick circuit means for said first stick relay controlled by a back contact of said third track relay and a back contact of said second stick relay, a second stick circuit means for said first stick relay adapted to include the wheels and axles of a vehicle in said first track section, an energizing circuit means for said second stick relay controlled by a back contact of said first track relay and a back contact of said third track relay and a back contact of said first stick relay, a first stick circuit means for said second stick relay controlled by a back contact of said third track relay and a back contact of said first stick relay, a second stick circuit means for said second stick relay adapted to be closed by the presence of wheels and axles of a vehicle in said second section, a highway crossing signal adjacent said intersection, a control rellay, circuit means for energizing said highway crossing signal controlled by a back contact of said control relay, circuit means for energizing said control relay controlled by a front contact of said third track relay and jointly by front contacts of said first track and stick relays, and jointly by front contacts of said second track and stick relays.

5. In combination, a stretch of railway track divided into first, second and third track sections by insulated joints, said third section being between said first and second section and intersected by a highway, a first, second and third track relays being associated with said first, second and third track sections, respectively, first and second stick relays associated with said first and second track relays, respectively, a first track circuit associated with said first section including said first track relay and a back contact of said first stick relay, a second track circuit associated with said second section including said second track relay and a back contact of said second stick relay, a third track circuit associated with said third section including said third track relay, a first and a second battery, an energizing circuit for supplying energy from said first battery to said first stick relay including a back contact of said second track relay and a back contact of said third track relay and a back contact of said second stick relay, a first stick circuit for supplying energy from said first battery to said first stick relay including a back contact of said third track relay and a back contact of said second stick relay, a second stick circuit for supplying energy from said first battery to said first stick relay adapted to include the wheels and axles of a vehicle in said first section, an energizing circuit for supplying energy from said second battery to said second stick relay including a back contact of said first track relay and a back contact of said third track relay and a back contact of said first stick relay, a first stick circuit for supplying energy from said second battery to said second stick relay including a back contact of said third track relay and a back contact of said first stick relay, a second stick circuit for supplying energy from said second battery to said second stick relay adapted to include the wheels and axles of a vehicle occupying said second section, a highway crossing signal, a control relay, a circuit for energizing said highway crossing signal including a back contact of said control relay, a first circuit for energizing said control relay including a front contact of each of said first, second and third track relays, a second circuit for energizing said control relay including a front contact of each of said first stick relays and said second and third track relays, and a third circuit for energizing said control relay in cluding a front contact of each of said first and third track relays and said second stick relay.

6. In apparatus for controlling a signal adjacent the intersection of a highway and a stretch of railway track, said stretch of track being divided into first and second approach sections and a crossing section, first and second track relays associated with said first and second approach sections, respectively, means responsive to traf fic conditions in said crossing section, first and second directional stick relays associated with said first and second approach sections, respectively, a track circuit for each approach track section including the associated track relay and controlled by the associated directional stick relay and closed only when the associated directional stick relay is deenergized, means controlled by said second track relay and said means responsive to traffic conditions in said crossing section and effective only when said second approach section and 'said crossing section are occupied for energizing said first directional stick relay, a stick circuit for said first directional'stick relay adapted to includethe Wheels and axles of a train in said first approach section, means controlled by said first track relay and said means responsive to trafiic conditions in said crossing section and effective only when said first approach section and said crossing section are occupied for energizing said second directional stick relay, and a stick circuit for said second directional stick relay adapted to include the wheels and axles of a train in said second approach section.

References Cited in the file of this patent UNITED STATES PATENTS 1,636,348 Young July 19, 1927 2,080,801 Allen et a1. May 18, 1937 2,370,704 Allen Mar. 6, 1945 10 2,677,047 Mishclevich Apr. 27, 1954

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