US2452868A - Directional control means for highway crossing signals - Google Patents

Description

J. A. QUINLAN Nov. 2 1948.

DIRECTIONAL CONTROL MEANS FOR HIGHWAY CROSSING SIGNALS Y Fi led Nov. 22, 1946 QTL r v A m1 Q .fib NM 7 is MN BO v8 SK TR mm mm Jarep v \N Q Q NESSR Q W N Q it HIS ATTORNEY Patented Nov. 2, 1948 DIRECTIONAL CONTROL MEANS FOR HIGH- WAY CROSSING SIGNALS Joseph A. Quinlan, Wilkinsburg, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application November 22, 1946, Serial No. 711,586

6 Claims. 1

My invention relates to directional control means for highway crossing signals, and more particularly to directional control of highway crossing signals by track instruments.

At some locations on a railway it is not practical or economical to use track circuits and it is necessary to resort to the use of track instruments to detect the presence of trains. When track instruments are used to control highway crossing signals, it is necessary to provide a directional control so that a train passing over a track instrument in approaching a highway intersection will initiate operation of the highway crossing signal, but that operation of the track instrument by a train moving awa from the intersection does not operate the signal. While directional track instruments are known, they are not entirely satisfactory.

Accordingly, a feature of my invention is the provision of an improved directional control of a highway crossing signal by non-directional track instruments.

Other features, objects and advantages of my invention will appear as the specification progresses.

The foregoing features, objects and advantages of my invention I attain by providing a novel relay and circuit arrangement governed by a group of track instruments located at different preselected points each side of a highway intersection.

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

In the accompanying drawing, which is a diagrammatic view showing one form of apparatus embodying my invention, the reference characters lb and lb designate the track rails of a stretch of railway track over which trafiic moves in either direction, and which stretch is intersected by a highway H. A highway crossing signal S is provided adj'cent the intersection, the signal S being here shown as a flashing light signal, although other types of highway crossing signals can be used.

A group of track instruments A, B, C, D, and E are provided, each individual instrument being operatively associated with the track rails. According to my invention the track instrument C is located adjacent the intersection with the highway, the instruments A and B arelocated relatively close together to the left of the intersection as viewed in the drawing, and the track instruments D and E. are located relatively close together to the right of the intersection. The distance the track instrument A is placed from the intersection is predetermined according tothe maximum permissible train speed for eastbound trains, that is, trains moving from the left to the .right, and the required warning period of the signal S prior to the arrival of a train at the intersection. Similarly, the distance the track instrument E is placed from the intersection is predetermined according to the maximum permissible train speed for westbound trains and the required period of warning operation of the signal. For example, if the maximum permissible train speed is miles per hour, or 134 feet per second, and a warning period of 20 seconds of the signal is required before the train reaches the intersection, the instruments A and E will be placed 2,680 (134 x 20) feet from the intersection. The track instruments B and D are positioned about feet from the track instruments A and E, respectively, and on the side toward the intersection. In the event very long trains are operated, the track instruments A and E would preferably be located from the intersection a distance greater than the longest train to be operated, and the warning period may be correspondingly increased.

These track instruments are shown conventionall for the sake of simplicity, since they can be of any one of several well-known forms. For example, these track instruments may be similar to the structure disclosed in Letters Patent of the United States No. 2,083,288, granted June 8,1937, to Herbert L..Bone, for Track rail contractors. It is sufficient for the present application to point out that each track instrument is attached to at least one track rail for operation of a circuit contact as a train wheel passes over the rail at the point the instrument is attached thereto, the contact being operated irrespective of the direction in which the train is moving. That is to say each track instrument is non-directional. Each track instrument A and E is provided with a contact biased to a closed position and operated to an open position when a train moving in either direction passes over the instrument. Each track instrument B, C, and D is provided with a contact biased to an open position and closed when a train moving in either direction passes over the track instrument. It is believed that the circuits and relays associated with this group of'track instruments to obtain directional control 'of the highway crossing signal S can best be understood from a description of the operation of the apparatus. I

It is to be pointed out that in several instances relay contacts are shown in the drawing remote from the relay winding in order to simplify the drawing. In each such instance the contact is identified by the reference character of the assoelated relay plus a distinctive numeral and the contact is shown in the position corresponding to the normal condition of the relay.

Normally, that is. when no train is Within the limits or the stretch of track involved, the apparatus occupies the position shown in the draw: ing. Under this normal condition a master stick relay AES is retained energized by a stick circuit which extends from terminal BA of a source of current such as a battery not shown through contact ill of track instrument A, line wire ll, contact I2 of track instrument E, line wire lg, front contact M- of relay AES, and the winding of the relay to the other terminal NA of the same source of current. The remaining relays are all deenergized and the signal S is inactive.

I shall first consider the manner of initiating the operation of the signal S when an eastbound in ap ro he he in e sect-i n- .W the leading wheel of the eastbound train passes over the trackins-trument A, the-contact it is actuated to its n Po t on and th s o e e s c coil; of master relay Afifi and that relay is deenersizcd and released and then remains released until a pick-up circuit to be described hereinafter s comp eted- T e rele se o ma relay AES close back contact l 5 completes an obvious circuit for a flasher relay of standard form, and that relay is set into operation to alternately operate its two contacts l6 and H. The release of relay ABS closing Toacl; cont-act 2.5 also completes a eenes t e o a nal e e ies ci c t a source Q P cr i el ct by the er nal 2; d (3 Thus the flash r ela F operated, t e two lamp l5 and o ign l S a e alter e 1- lu rninatedpy power from the BX-CX source, and this flashing of the lamps l8 and 19 serves as a warnin ediee en o i h use s f the p each -tihs ees beim trem- The leading train Wheel of this eastbound train ne t s aces the rack in t n B Closing its s A and 3 are located relatively close together. The contact 20 is included in the circuit for a relay 13D, to be referred to hereinafter, but

rent 3.? performs no useful function at this time and t sta na i n ee mi c de d A the easthound train approaches the intersection,

the operation of the signal S is continued, due to the fact that the plaster relay AES remains deenrsi sd and he flasher l y F s Supplied with power.

' I shall next consider the manner Joy which the warning operation of the signal S is continued until the rear of the train passes over the intersection and the operation isthen stopped. When the train reaches the intersection, the leading train wheel actuates the tracl; instrument 0 closing its contact ,2! to complete a simple circuit for a slow release relay GP and that relay is energized. Relay CE is provided with a resistor 22 and a capacitor th; my oll i' ui et een mot er of e r W 1t l y Q itt up an alt rn e c t for its asher. relay i closed a rom c c 24 of relay CP and an alternative connection to the t et 29 it-temg recalled that the two instrw' connected in eries across the winding of .the'

mL in power source is completed at front contact at of relay CP. It follows that the operation of the si nal S is continued while the train passing over the track instrument C which is adjacent the intersection unless the train actually stops in a position where no wheel is over the instrument C. When the last wheel of the train passes over the track instrument C, it is restored to its normal condition and the relay CP is deenergized and released at the end of its slow release period so that the alternative circuits for the flasher relay FR and the supply of par-"er for signal opened to stop the operation of the signal, providing of course that the master relay AES has in the meantime been reenergized in a manner to he now explained.

The reenergizing of the master AES is accomplished by operation or" stick relays CS and CSP and a time element relay the operation being initiated relay CP. The relay CS is energized by current flowing from terminal BA through front contact 25 of relay CP, normally closed check contact 23 of the time el-ercent relay CTE, and winding of relay CS to the terminal NA, and the relay CS is picked up to close a stick circult including its own front contact 29 2 back contact of the master relay AES. Relay CS on picking up, closing front contact completes an obvious circuit for the time element relay GTE. Relay CTE is a time element relay preferably of the thermal type, wherewith a normally open contact is closed at the expiration of a fixed period after the heating element of the relay is supplied with power. Relay C'IE is proportioned for an operating period shown in the drawing as being 15 seconds, but other time intervals can be used. Thus it can he said of the time element relay CT that immediately after current is sup lied to its heating element as, its check contact 28 is opened and at the end of a 15 seconds operating period its contact 35 is closed. When the relay CS i -picked up, closing front contact a pick-up circuit for relay CS? is completed, this pick-up circuit also including a resistor 33. Relay CSP on picking up completes a stick circuit at its own front contact 3% and it also closes a front contact 36 to prep-are a pick-up circuit for the master relay ABS and which pick-up circuit also includes contact 35 of relay CTE. Thus, at the end of the 15 seconds operating period for the relay CTE, the closing of contact 35 of relay TE complete the pick-up circuit for the master relay AES and that relay is reenergized and picked up. Relay AES on picking up closes its stick circuit which Was described hereinbefore, and it is retained in its normal energized condition by the stick circuit since contact it of the track instrument A. was reclosed when the rear of the train passed that point. The master relay AES on pick ng up to open the back contacts 55, 2t and 39, opens at the contacts l5 and 26 the first operating circuit for flasher relay PR and the first power connection for the signal S. The opening of back contact 3i opens the stick circuit for relay CS and relay CS on releasing opens front contact 3! through which power is supplied to the time element relay CTE, and also opens the pick-up circuit for the relay CSP at front contact 32.

There may be a thermal time lag in the restoring of contact 35 to its open position after the heating element 48 of relay GTE is without power. Such time lag in the restoring of contact 35 does not retain the pick up circuit of the master relay AES closed unduly long because when contact 35 is closed it places a shunt across relay CSP and that relay is shunted in a short period of approximately 1 second, and with relay CSP released the pick-up circuit of the master relay AES is open at front contact 36 of relay CSP. This prompt opening of the pick-up circuit of the master relay assures that a second or following eastbound train cannot pass track instrument A and relay AES does not respond thereto.

It follows that as the eastbound train recedes from the intersection, the warning operation of the signal S is stopped and the relays and circuits are restored to their normal condition ready to respond to a following eastbound train.

I shall next consider the operation of the apparatus as the eastbound train passes over the track instruments D and E. When the leading wheel of the train operates track instrument D, closing its contact 31, current flows from terminal BA through contact Ill of track instrument A, line wire ll, contact I2 of track instrument E, contact 31 of track instrument D, line wire 38 and winding of relay BD to terminal NA, and the relay ED is energized and picked up. The closing of front contact 39 of relay BD completes an alternative circuit path for the stick circuit of 'the master relay AES, so that relay AES is retained energized when the eastbound train passes over the track instrument E opening its contact I2 which is interposed in the normal stick circuit of the master relay. A resistor 40 and a capacitor M in series are connected across the winding of relay BD and that relay is provided with a slow release period sufiicient to assure that the relay is not released in the case the contact 3? of instrument D is opened momentarily between :1.

trucks of the eastbound train and also the relay is not released while the rear of the train is moving between the track instruments D and E. It is apparent from the foregoing description that the apparatus here disclosed provides directional control for the highway crossing signal S so that the signal is operated to give a warning indication while the eastbound train approaches the intersection and passes over the intersection and the warning operation is discontinued while the train recedes from the intersection and passes over the track instruments D and E provided for westbound trains.

Operation of the apparatus for a westbound train is similar to the operationior an eastbound train and the operation for a westbound train need not be explained except to point'out that when the leading wheel of the westbound train actuates track instrument E opening its contact [2, the stick circuit of the master relay AES is' opened and that relay is released to energize flasher relay FR and supply power to the signal S whereby the warning operation of the signal is initiated. Operation of the track instrument D by the westbound train efiects no useful func-' tion. Operation of the track instrument C by the westbound train energizes relay GP to continue operation of the signal until the rear of the train passes completely over the intersection and 7 the track instrument C is restored to its normal condition. Energization of the relay CP also sets in motion operation of the relays CS, CTE and CS1? to reenergize the master relay'A'ES in the manner explained hereinbefore. Operation ofthe track instrument B as the westbound train recedes from the intersection closing contact 2%) completes a circuit for relay BD and that relay is picked up closing front contact 39 which closes the alternative circuit path for the stick circuit -of the master relay AES so that the master" relay is" not released as the westbound train moves over the track instrument A. l

To sum up the operation, the warning operation of the signal S is started when an eastbound train reaches track instrument A and when a westbound train reaches track instrument E. The warning operation of the signal is continued in either case until the lapse of a given period after the rear of the train passes the track instrument C. Furthermore, operation of the signal is avoided when the track instrument E is operated by an eastbound train and when the track instrument A is operated by a westbound train.

Atime element relay ATE and another relay AET areprovided to restore the apparatus to its normal condition in the event a loss of power occurs or in the event the stick circuit for the master relay AES is inadvertently opened for a moment. Assuming a loss of power occurs and the master relay AES is released, a circuit is completed from terminal BA through back contact 62 of relay AES, heating element 39 of relay ATE and back contact is. of relay AET to the terminal NA and the time element relay ATE is set into operation when power is reapplied. The operating period of the time element relay ATE is made relatively long and in the drawing it is indicated as being a period of 3 minutes, but other periods can be used. This operating period for the relay ATE is made longer than the normal time required for a train to pass through the stretch of track, that is, to approach and pass over the intersection. When relay ATE has operated its fixed period of time, contact 44 is closed to complete an obvious pick-up circuit for relay AET and that relay is picked up and completesa stick circuit for itself through its own front contact t5 and back contact all of the master relay AES. With relay AET picked up opening back contact 43, the time element relay ATE is without power and it is restored to its normal position after a short time lag. The closing of check contact 46 of the time element relay ATE completes an alternative pick-up circuit for the master relay through contact as of the time element relay and front contact 41 of relay AET, with the result the master relay is restored to its energized condition closing its stick circuit by which it is normally retained energized. When the master relay AES is picked up opening back contact to, the relay AET is deenergized and restored to its normal condition.

It is to be noted that in the event a train stops and remains in the approach section to the intersection, the operation of the signal will be stopped after a period due to the action of the relays ATE and AET in the manner just explained. In the event this train later approaches the intersection the signal will be operated while the train is passing through the intersection due to the operation of the track instrument C.

Apparatus such as here disclosed has the advantages that dire-ctional control is provided for highway crossing signals through the medium of non-directional track instruments of relatively simple construction.

Although I have herein shown and described but one form of directional control means for highway crossing signals embodying myinvention, 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 ofmy invention..

aeeasae 6 Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a first track instrument located at a selected point to one side of the intersection, said track instrument having a contact biased to a closed position and opened by a train passing over the instrument, a master relay having a stick circuit completed through said contact of the first track instrument, operat-- ing circuit means having a first path governed by said master relay to operate said signal when the master relay is deenergized, a second track instrument located adjacent said intersection'and having a contact biased to an open position and closed when a train passes over that instrument, a slow release relay energized through said contact of the second track instrument, a second circuit path of said operating circuit means governed by a contact of said slow release relay to operate the signal when the slow release relay is picked up, a first restoring circuit means including a time element relay having a contact closed in a preselected relatively short period of time and governed by said slow release relay when picked up, a second restoring circuit means including a time element relay having a contact closed in a preselected relatively long period of time and governed by said master relay when released, and a pick-up circuit means for said master relay and made efiective when the contact of either of said time element relays is closed.

2. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a first track instrument located at a selected point to one side or the intersection, said track instrument having a contact biased to a closed position and opened by a train passing over the instrument, a master relay having a stick circuit completed through said contact of the first track instrument, operating circuit means having a, first path governed by said master relay to operate said signal when the master relay is deenergized, a second track instrument located adjacent said intersection and having a contact biased to an open position and closed when a train passes over that instrument, a slow release relay energized through said contact of the second track instrument, a second circuit path of said operating circuit means governed by a contact of said slow release relay to operate the signal when the slow release relay is picked up, restoring circuit means for said master relay and including a first and a second stick relay and a time element relay, said time element relay having a contact which is closed only after the relay is supplied with power for a given time interval, said first stick relay having a pick-up circuit including a front contact of said slow release relay and a stick circuit including a back contact of said master relay, said second stick relay having a pick-up circuit including a front contact of said first stick relay and a stick circuit including a resistor, means including a front contact of said first stick relay to supply power to said time element relay, a pick-up circuit including said time element relay contact and a front contact of said second stick relay to reenergize said master relay, and said time element relay contact disposed when closed to shunt said seccnd stick relay.

3. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a first track wheel passes over the instrument, a master relay having a normally closed stick circuitincluding said first track instrument contact, operating means for said signal governed by said master relay to operate the signal when the master relay is deenergized, a second track instrument attached to a rail of the stretch ata point relatively near the first track instrument on the side toward the intersection, said second track instrument having a contact biased to an open position and closed when a train wheel passes over that'instrument, a slow release relay energized through said second track instrument contact, and an alternative path including a front contact of said slow release relay for said stick circuit-of said master relay to retain the master relay energized when a train passes over the first track instrument in reced ng from the intersection.

4. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a first, a second and a third track instrument which a train passes in the order named in approaching the intersection; said first track instrument having a contact biased to a closed position and opened when 'a train wheel passes over the instrument and each said second and third track instruments having a contact biased to an open position and closed ;when a train wheel passes over the instrument,

a master relay having a normally closed stick c rcuit including said first track instrument contact, circuit means governed by said master relay when deenergized to operate said signal, a slow release relay having an energizing circuit including said third track instrument contact, another circuit means governed by said slow release relay when energized to operate said signal, another slow release relay having an'energizing circuit including said second track instrument contact, and a circuit path including a front contact of said another slow release relay to shunt said master relay stick circuit around said first track instrument contact.

5. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection; a first, a second and a third track instrument which a train passes in the order named in approaching the intersection, said first track instrument having a contact biased closed and opened by a passing train and each said second and third track instruments having a contact biased opened and closed by a passing train, a master relay having a normally closed stick circuit and a normally open pick-up circuit, said stick circut including said first track instrument contact, a first slow release relay hav ing an energizing circuit including said third track instrument contact, operating means for said signal controlled by alternative circuit-paths one of which includes a back contact of said master relay and the other of which paths includes'a front contact of said first slow release relay, means including another relay and a time element relay controlled by said first slow release relay when energized to momentarily close said pick-up circuit in a predetermined time interval to reenergize said master relay, a second slow release relay having an energizing circuit including said second track instrument contact, and a circuit path including a first contact of said second slow release relay to shunt said stick circuit or the master relay around said first track instrument contact.

6. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a first and a second track instrument on one side of the intersection and operated in the order named by a train approaching the'intersection on saidone side, a third track instrument located adjacent the intersection, afourth and a fifth track instrument on the other side of the intersection and operated reverse to the order named by a train approaching the intersection on said other side, said first and fifth -track instruments each having a normally closed contact which is opened by a passing train; said second, third and fourth track instruments each having a normally open contact which is closed by a passing train, a master relay normally energized by a stick circuit including in series the contacts of said first and fifth track instruments, a slow release relay having an energizing .circuitincluding the contact of said third track instrument, operating means for said signal having alternate paths one including a back contact of said master relay and one including a front contact of said slow release relay, circuit means including a time element relay and controlled by said slow release relay when energized to close a pick-up circuit for said master relay, another slow release rela energized through the contacts of said second and fourth track instruments in multiple, and a circuit path including a front contact of said another slow release relay to shunt said stick circuit of the master relay around the contacts of said first and fifth track instruments.

JOSEPH A. QUINLAN REFERENCES CETEE) The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Linker Feb. 13, 1917 FOREIGN PATENTS Country Date Austria Mar. 25, 1937 Switzerland June 1, 1937 Austria Mar. 25, 1938 Number Number

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