Railway traffic controlling apparatus

June 9, 1936. c. w. failor 2,043,740

RAILWAY TRAFFIC CONTROLLING APPARATUS

Filed Aug. 26, 1933

Sheets-Sheet 1

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June 9, 1936. c. w. failor 2,043,740

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Aug. 26, 1933 2 Sheets-Sheet 2

Code A or B /4 CodeC S^CoD&amp;AorB

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CodeE/G Gode D 7 Code E Code D

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MTS ATTORNEY

Patented June 9, 1936

2,043,740

UNITED STATES PATENT OFFICE

2,043,740

RAILWAY TRAFFIC CONTROLLING .: APPARATUS

Charles W. Failor, Forest Hills, Pa., assignor to The Union Switch &amp; Signal Company, Swissvale, Pa., a corporation of Pennsylvania

Application August 26, 1933, Serial.No. 686,970

Claims. (Cl. 246—34)

My invention relates to railway traffic controlling apparatus, .and more specifically to apparatus for providing broken-down insulated rail joint protection in traffic governing systems which uti5 lize coded rail current for controlling wayside and/or cab signals.

I will describe three forms of railway traffic controlling apparatus embodying my invention, and will then point out the novel features therc.10 of in claims.

In Fig. 1 of the accompanying drawings, I have shown several types of code suitable for use with apparatus embodying my invention. Figs. 2, 3 and 4 are diagrammatic views showing appara15 tus embodying my invention which is adapted for _t.use with different pairs of the codes illustrated in

Fig. 1.

In systems employing two-element track relays, broken-down rail joint protection is readily 20 obtainable through the staggering of polarities of adjoining track circuits. This method is, however, of no avail in the case of circuits using the more simple and less expensive single element, two position track relay. The present invention . 25 is directed to the provision of complete brokendown rail joint protection, irrespective of traffic conditions, in coded wayside and cab signaling systems, the track circuits of which employ the single-element code-following track relay.

³⁰ Since staggered polarities cannot be used advantageously in track circuits of this type, I propose to stagger certain elements of the code supplied to adjoining track circuits and to provide apparatus distinctively responsive to the two types ³⁵ of code, thereby preventing the display of false clear signals. With this arrangement, should the code of one track section pass over defective rail joints into the adjoining section, a restrictive signal will be displayed.

⁴⁰ In carrying out the purpose of my invention, adjoining track circuits are supplied with currents of distinctive character, obviously, the particular type of current which may be used as the carrier, and upon which may be impressed ⁴⁵ the characteristic which renders adjoining track circuits distinguishable from the standpoint of the code-following track relay is immaterial. For example, numerous codes met with in the signaling art, such as the frequency code, count code, ⁵⁰ - polarity code, time code, to name only a few, can be modulated in such a manner as to provide distinctive response in adjoining track, circuits, for the purpose of broken-down rail joint detection.

In order not to complicate the disclosure un⁵⁵ duly, I have chosen but two types of code, for purposes of illustration, these being the frequency code, illustrated at A, B and C of Fig. 1, and the time code shown at D and E of the same figure.

Referring to Fig. 1, code C is the usual frequency code used in systems of wayside and cab 5 signaling' and comprises, ordinarily, an alternating .current carrier of any suitable frequency, upon which are impressed periodic variations occurring at the rate, for example, of 180, 120 or 80 per minute, as determined by traffic condi- 10 tions. These variations can be impressed upon a direct current carrier with like effect.

’ Code A differs from code C only in that a relatively long “on” interval is interposed periodically in the code. This can be readily accomplished 15 in a motor-driven cam type of code transmitter by mutilating that portion of the contact-operating cam which forms certain of the “off” code intervals, such as are shown dotted at a. Code A will be applied to a given track section, and it 20 will be understood that the codes of other periodic frequencies, which may be supplied tb this track section under different traffic conditions, will be similarly modified by means of a long “on” interval. ²⁵

Code B is similar to code A but instead of having a periodically recurrent long “on” interval, this, code has a periodically recurrent long “off” interval. Code B is intended to be supplied to the track section adjoining the section supplied with.³⁰code A. The long “off” interval of code B can likewise be readily obtained by mutilating the code transmitter cam to eliminate the “on” intervals shown dotted at b.

Codes D and E are time codes having long “on”, ³short, “off”, and, short “on”, long “off” intervals, respectively. These codes may be used alternately in adjoining track sections in territory equipped for .wayside signaling only, or for both wayside.and cab signaling, provided that the Ipcomotive equipment which is used is of such character as to be operative on impulses of the time code.

Referring now to Fig. 2,1 have shown a stretch ₄₅of railway track divided into sections I—2 and 2—3, each of which is normally supplied with coded alternating current, by means of a track transformer designated by the reference character T, with an exponent corresponding to the ₅θ location. The normal traffic direction is from left to right, as indicated by the arrow. It will be noted that the codes of adjoining track sections are staggered, that is, the section immediately to the left of location I is supplied with ₅₅code A, section I—-2 is supplied with code B, sec

2,043,740 tion 2—3 with code A, and the section immediately to the right of location 3 is supplied with code B, these being the codes represented diagrammatically in Fig. 1.

The operation of the apparatus will first be explained with reference to section 2—3. With no train present, the rails of this section will normally be supplied with coded current from transformer T³, resulting in operation of the 10 code-following track relay TR², in step with the code. Relay TR² is of the direct current type, and is energized through the relay transformer RT² and rectifier R², the condenser C² and reactor X² being used to exclude propulsion cur15 rent and foreign current of non-signaling frequencies. If relay TR² is of the alternating current type, it may be connected directly with the rails, eliminating the auxiliary apparatus.

It will be assumed that the periodic frequency ²θ of code A is either 180, 120 or 80 per minute, according to the condition of traffic in advance sections. Relays F² and E² are frequency selective and are responsive, respectively, to the 180 and the 120 code. The energization of these relays ²⁵ is obtained in the customary manner, by converting direct current from a source B—C applied over contacts 9—iO and 9—I i of relay TR², into alternating current in the secondary of decoding transformer DT². The output of trans³⁰ former DT² is supplied to the usual decoding units DE² and DF² which comprise a condenser and a reactor tuned to the desired code frequency, as well as a rectifier if relays E² and F² are of the direct current type as is commonly the case. ³⁵ The energizing circuits for relays Ξ² and F² have not been shown in detail, since these circuits are the same as are commonly used in code systems of cab signaling, and are well-known.

Relays TRP², TP² and H² are controlled through 40 the operation of contacts 12—13 and 12—14 of relay TR², and in the present disclosure, these relays take the place of the usual 80 code relay. The release time interval of relay TRP² is so adjusted that this relay, having a pickup circuit 45 over back contact 12—!4 of relay TR², will remain energized as long as relay TR² is following the ordinary impulses of the 180, 120 or 80 code frequencies, but will release during the periodically recurrent long on impulse which is 50 the distinguishing characteristic of the 180, 120 and 80 codes comprising code A. The release interval of relay TP² is such that the periodic opening of front contact 15—16 of relay TRP²will not deenergize this relay. Also, relay H² is 55 sufficiently slow acting to insure that the periodic closing of back contact 15—IT of relay TRP² will maintain relay H² in its energized position.

When the code supplied to transformer T³ is either 180 or 120, code transmitter CT² will sup00 ply 180 code to transformer T² for the rear track section 1—2, from a suitable alternating current source BX—CX, over a circuit which includes the front contacts 18—19 and 21—22 of relays TP² and H², as well as front contact 24—25 of 65 relay F², or alternatively, front contact 27—28 of relay E² and back contact 24—26 of relay F², according as relay TR² is following 180 or 120 code, respectively. If transformer T³ is supplied with 80 code, transformer T² will receive 120 code 70 over back contacts 27—29 and 24—26 of relays E² and F², and front contacts 21—22 and 18—19 of relays H² and TP². Consequently, as long as relay TR² is following any one of the code frequencies embraced within code A, the rear sec75 tion 1—2 will receive either 120 or 180 code.

When a train enters section 2—3, relay TR², and therefore relays TP² and H², will become deenergized, and the 80 or restrictive code will be furnished to transformer T².

The indications of signal S² are controlled by 5 the relays TP², Η², E² and F², in accordance with the code received by relay TR². The specific signal control circuits are not shown, as these are in accord with usual practice. Similarly, the indications of signal S¹ are controlled by the 10 decoding relay group for section I—2.

Considering section I—2 which is supplied with code B having a long off interval recurring periodically in the code, it will be noted that in this case, relay TRP¹ is controlled over a front 15 rather than a back contact of the code-following track relay in order that relay TRP¹ will have an opportunity to release during each long off interval, in the same manner that relay TRP²of section 2—3 was permitted to release during 20 each long on interval of code A. The control of relay H¹ is identical with the control of relay H², that is, relay H¹ remains energized provided that relay TR¹, and consequently relay TRP¹, follows the long off period in the code at intervals 25 which recur within the release period of this relay.

To explain the manner in which the circuit functions to provide broken-down rail joint protection, let it be assumed that section 2—3 is occupied, so that signal S² will display its most 30 restrictive indication, and that while section 2—3 is so occupied, the rail joints at location 2 are broken-down, permitting relay TR² to become energized and to follow code B which flows over the rail joints from section ί—2. The code fre- 35 quency of code B, under this traffic condition will be 80. Were no protection provided, this 80 code might energize the 80 code relays of section 2—3, stepping up the code supplied to section f—2 from 80 to 120. Thereupon, the 120 40 code relays of section 2—3 would respond to step up the code for section I—2 to 180, which code when applied behind the train in section 2—3 might result in a false clear indication at signal S².

However, because of the absence of the long 45 on interval in code B, relay TRP² will not be deenergized periodically, thus providing no energizing impulses for relay H², as a result of which relay H² will remain deenergized. Therefore, the code frequency supplied to section I—2 will re- so main at 80, and signal S² will continue to indicate the occupied condition of section 2—3.

If 80 or 120 code is being fed to section 2—3 at the same time that 120 or 180 code is being fed to the rear section I—2, and the rail joints 55 break down, relay TR² will be following an irregular code, the resultant of codes A and B, which will ordinarily keep this relay energized almost continuously. If the code transmitters CT² and CT¹ are of the induction motor type and 60 are not synchronized, beat notes will usually occur, resulting from the two codes occasionally passing in and out of synchronism. Therefore, one or the other of relays TP² or H² will pick up or release occasionally, according as the two codes 65 A and B tend, at the moment, to annul or to aid each other, resulting in an occasional flashing indication being obtained at signal S², which aids detection of the faulty rail joint.

The manner in which relay TR¹ operates on 70 code B and provides protection against improper signal operation by code A from an adjoining section is as follows: It will be noted that relay TRP¹ is energized over a front contact of relay TR¹, and since code B has a long off interval, 75

2,043,740 relay TRP¹ will be deenergized at each long off interval, thereby maintaining the slow-releasing relay H¹ constantly picked up. The release time of relay TP¹ is sufficient to bridge the re5 lease period of relay TRP¹, so that normally, relay TP¹ also remains , picked up. If code A from an adjoining section either forward or in the rear of section i—2 should flow in the rails of the section, the absence of the long off in10 terval would prevent relay TRP¹ from releasing periodically, thus causing relay H¹ to release, and insuring the display of a restrictive indication at signals S¹.

It will be apparent from the foregoing descrip15 tion that by staggering the codes which are applied to adjoining track circuits, complete broken-down rail joint protection can be obtained. The released condition of relay H¹ or relay H²may, of itself, be used to provide an indication 20 that the rail joints at location I or 2 are brokendown.

In Fig. 3, I have shown how a standard code such as code C of Fig. 1, can be staggered with either of codes A or B, to provide the desired pro25 tection. Referring to Fig. 3, the decoding apparatus of this figure is similar to the standard decoding group used in frequency code systems of signaling with the exception that the usual 80 code relay is replaced by the two relays TP^{4 30} and H⁴. When relay TR⁴ is operating on code C, both relays TP⁴ and H⁴ remain constantly energized. Should code A from an adjoining section energize relay TR⁴, the long on interval of this code would cause relay TP⁴ to release pe³⁵ riodically, to cause flashing of the signal. If relay TR⁴ is energized by code B, the long off interval of this code will similarly cause relay H to release periodically, and to flash the signal.

Referring to Fig. 4/the circuits shown therein 40 illustrate one way in which the principle of code staggering can be applied to a signaling system employing the time code, of which codes D and E of Fig. 1 are representative. To simplify the disclosure, direct current from a suitable bat45 tery source is Used as the carrier for the code, instead of alternating current, and but one form of the characteristic code is supplied per track circuit by code transmitters CT, it being understood that for multiple aspect signaling each of 50 codes D and E would in practice comprise modified forms based on different time ratios between the on and off intervals, for providing distinctive signal aspects in accordance with traffic conditions. Track sections 6—Ί and 1—8 represent 55 cut sections within a block, and the block signals and associated control circuits are omitted from the drawings as these are not essential for an understanding of the invention.

Considering section I—8, the code supplied to ⁶⁰ track relay TR⁷ by code transmitter CT⁸ is code E of Fig. 1, and comprises relatively short periodic on intervals separated by relatively long off intervals. Relay TRP⁷ is so designed that it will release during each long off interval of ⁶⁵ the code, and relay TP⁷ is designed to bridge the release interval of relay TRP⁷. Therefore, each time that relay TRP⁷ releases, relay TPP⁷will receive an impulse of energy, which will maintain relay TPP⁷ constantly picked up, keep70 ing the signal control circuit closed at front contact 30. Should relay TR⁷ become accidentally: energized by code D from the adjoining section, the short duration of the off interval of code D would prevent relay TRP⁷ from releasing. 7® Therefore, relay TPP⁷ would become deenergized and would open the signal circuit at contact: 30, to provide the necessary protection.

In. section 6—7, relay TRP⁶ is designed: to release during each long on interval of code D, and relay TP⁶ is sufficiently slow-acting to bridge 5 the release interval of relay TRP⁶. Therefore, relay TPP⁶ will be maintained in its energized position by virtue of the periodic impulses of energy which it receives each time that the back contact of relay TRP⁶ is closed. As a result, 10 the signal control circuit will be maintained closed at front contact 31. The manner in which relay TPP⁶ will release the open contact .31, should code E from an adjoining section falsely operate relay TR⁶, will be clear without added 15 description.

It will be understood, of course, that the staggered .codes of a given stretch of track need not belong to one group, such as the frequency code or the time code group, because one track· cir- ²⁰cuit may be supplied with frequency code, such as code A, B, or C, and the adjoining track circuit with time code, such as code D or E, provided that decoding apparatus distinctively .responsive to the particular code for the section be ²⁵used.

Although I have herein shown and described only a few forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within ³⁰the scope of the appended claims without departing from the spirit and scope of my invention.