US2169603A - Railway traffic controlling apparatus - Google Patents

Description

Aug. 15, 1939. c, w FAILOR 2,169,603

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Feb. 23, 1938 3 Sheets-Sheet 1 IN NTOB Charle Fazlar BY 2 HIS ATTORNEY Aug. 15, 1939. c. w. FA'lLoR RAILWAY TRAFFIC CONTROLLING APPARATUS s Sheets-Sheet 2' Filed Feb. 23, 1938 $5 Q25 owvwn Patented Aug. 15, 1939 UNITED s'ra'rss PATENT OFFICE RAILWAY TRArrro CONTROLLING APPARATUS Application February 23, 1938, Serial No. 191,939

20 Claims.

My invention relates to railway trafiic controlling apparatus of the class wherein coded track circuit energy is utilized to control either or both wayside signals and train-carried governing devices and more particularly it relates to the trackway portions of such apparatus and to the manher of organization thereof.

One object of my invention is to provide a novel and improved form of such organization.

Another object is to make a novel utilization of counting-chain relays in decoding apparatus for the control of wayside signals.

An additional object is to provide trackway codes utilizing spaced pulses of both normal and reversed polarity energy which are e'fiective to control both my improved wayside decoders and train-carried decoders of the usual frequencyselective type.

A further object is to make provision for applying the trams-governing apparatus to automatic signal blocks which both do and do not contain cut sections.

A still further object is to provide for the clearing of track circuits of out sections without interfering with the desired control of the wayside and train-carried decoding equipments.

I shall describe one representative form of traffic controlling apparatus embodying my invention and shall then point out the novel features thereof in claims. This illustrative embodiment of my inventive improvements is disclosed by the accompanying drawings, in which:

Figs. 1a and 1b are diagrammatic views which when placed end to end in the order named represent a stretch of railway track equipped with trafiic-controlling apparatus embodying my inventicn;

Fig. 2 is a diagrammatic representation of some trackway-energy codes which may be used to control the apparatus of Figs. 1ab;

Fig. 3 is a series of views indicating one manner in which the coding-device contacts for producing the four codes represented in Fig. 2 may be arranged and actuated;

Fig. 4 is a diagrammatic representation of the effect of the presence of a train in a block upon the track relay and the wayside traffic-controlling relays of a number of blocks and also upon the cab signals of a following train; and

Fig. 5 is a diagrammatic representation of cab signal circuits of conventional frequency-selective character which are suitable for cooperation with and control by the trackway apparatus 'of the my invention are there disclosed as being incorporated in a combined automatic block and cab signaling system for a track i2 over which trafiic moves in the single direction designated by the arrows, or from left toright in the dia- 5 grams. Insulated joints 3 divide the rails of the protected stretch of this track into the customary successive sections LLa, LaM, etc. In the stretch of track which is represented in Figs. 1a and 1b, the locations L and M mark the points of main signal block division while the location La represents a subdivision of one of these main signal blocks. This particular subdivision is cocasioned by a highway 3 which crosses the track within the confines of the block LM and with which the usual crossing protecting signals XS are associated.

Positioned at the entrance of each of the main signal blocks is a wayside signal S which is adapted to indicate to an approaching train the nature of the traflic conditions in the blocks immediately ahead. The block-subdividing location represented at La, being within the confines of the block LM which is protected by signal SI, has only the highway crossing protection devices XS and no wayside signal associated with it.

The wayside signals S shown by way of illustration at the locations L and M are of a wellknown color-light type and each comprises an upper unit of three lamps G, Y and R, and a lower unit of two lamps G and B. When lighted the two lamps G and R of both units respectively display the colors of green and red and lamp Y of the upper unit displays the color of yellow. These signals are arranged to show any one of four different aspects which respectively signify the indications of clear, caution, slow and stop. For purposes of explanation it will be assumed that these particular indications are identified with the aspects of green-over-red, yellow over-green, yellow-over-red and red-over-red, as respectively represented at locations I, J, K and L in Fig. 4.

The rails of each of the referred to sections of track form a part of a. track circuit which is adapted to transmit train-control energy in the .usual manner. In the particular arrangement represented each of these track circuits further includes the control winding of a track relay TR. which is installed at the traflic-entering end of the section and a track transformer TT connected, through the usual current-limiting reactor ?6, with the rails thereof at the traffic-leaving or exit end of the section.

Operating energy is supplied to each track cirtact I80 and conductor I5.

cuit through the transformer TT. This energy may, of course, be derived from any suitable alternating current source and distributed to the several locations of track circuit division L, La, M, etc., by the aid of a transmission circuit (not shown) extending along the right of way in the usualmanner. In the diagrams, characters B and C designate power-distributing terminals which are supplied from one such source, the frequency of which will be assumed to be of the usual signalpower value of 60 or 100 cycles per second.

Interposed between the power-source terminals B and C and the energizing circuits for the track transformers 'IT are supply'transformers 8 the secondary winding of each 'of which is provided with a mid-tap 9. One side of the primary winding of each track transformer TT is directly connected, by means of a conductor II, with this mid-tap of the associated supply transformer 8 and the other side of the track transformer primary is selectively connected, through a conductor I2 and the contacts of a code transmitter CT,

': sively repeated. These code-cycle pulses are produced by' interrupting the rail-supply circuit a definite number of times per minute and by reversing, during a portion of each cycle, the relative instantaneous polarity of the energy which is fed into'the circuit.

The particular transmitter shown at CT employs a circuit makinge and-breaking contact 80 to produce the slow code, a second contact I to produce the caution code, and a third contact I80 to produce the clear' code. By a motor or other suitable mechanism (not shown in detail), these contacts are continuously actuated at three different speeds which for purposes of explanation will be assumed to be such as respectively to provide the referred to codes of 80, 120 and 180 energy pulses per'minute. All of these transmitters are arranged to operate continuously and to this end they are constantly supplied withsuitable actuating energy from source B-C.

Selection of which one of the three coding contacts above named is included in the energizing circuit of the associated track transformer T1 is effected by contacts I4 of a group of traflic-governing relays H, D and DD which form a part of the equipment installed at each of the wayside signal locations L, M, etc. When the contacts 7 of both of the relays H and D are picked up the track transformer receives energy of the clear code through a circuit which includes coding con- When the contacts of relay Hare picked. up and those of relay D are released, the transformer circuit includes coding contact I20 and a conductor I6 and then is supplied with energy of the caution code. 7 Finally,

when the contacts of both of the relays H and D V cludes coding contact 80 and a conductor H.

In all three instances the postive or normal- I polarity pulses of code energy are suppliedlfrom the upper half of the secondary of the supply transformer 8 or portion thereof above the midtap 9, and the negative or reversed-polarity energy pulses are supplied from the lower half or portion of the winding below the tap 9. Polarity selection is determined by whether the active coding contact (80, I20 or I80) is moved upwardly or downwardly from the midway of neutral position which is represented in full lines in the diagrams.

One form of code-transmitter mechanism for" actuating these contacts in the special way indi- L cated is shown in Fig. 3. There each of the coding contacts is represented as being associated with a constantly rotating cam shown immediately therebeneath and the periphery of which is provided with regularly spaced lobes and depressions. As shown, the 80-contact cam has three such lobes or protrusions and one depression, the I20- contact cam has three lobes and one depression, and the I80-contact cam has four lobes and two depressions. the 80 contact connects conductor I! with the upper terminal of the supply winding two successive times and with the, lower terminal of With this illustrative arrangement, a

the supply winding once during each code cycle;

the I20 contact connects conductor I6 three suc cessive times with the upper winding terminal duration of second and consecutive pulses are,

spaced by the same period of time; in the case of the I20 or caution code each of the pulses and spaces has a length of second; and in-the case of the I80 or clear code each of the pulses and spacing periods has a length of second.

From Fig. 2 it will further be seen that each com v plete cycle of the 80 code has a total duration of 7 2% seconds, each complete cycle of the I20 code is 2 seconds in length, and each complete cycle of the I 80 code also has a duration of 2' seconds This means that in producing the clear code of Fig. 2 the I80 contact cam of Fig. 3 must make revolutions per minute; in producing the caution code the represented I20 contact cam must rotate at the same speed; and in producing the slow code the represented 80 contact cam must operate at the slower speed of 26 revolutions per minute. r

In a code transmitter of the particular type which is shown at CT inFig. 1, the I80 and shown) at the above stated speed of 30 revolutions per minute. Because, however, of its requirement of a slower operating speed (26% R. P M.) V

selecting relay H or D can under no circumstance introduce into the first cycle of the newly selected code a number of normal-polarity pulses in excess of the preselected quantity. As will be seen presently, this precaution prevents the controlled wayside signal S from giving a momentary flash of a less restrictive indication on the occasion of a new code selection.

The circuits which are efiective during the transmission to the trackway of both the normal and reversed polarity energy pulses of the first three or traflic-governing codes represented in Fig. 2 will now be traced. In all instances this transmission is to the rails of the track section to the rear of the section-dividing location where the transmitting apparatus is installed and by way of the associated track transformer TT.

In the case of the 80 or slow code, the normal-polarity-pulse circuit extends from the upper terminal of the secondary winding of transformer 8 through conductor 29, the coding contact 80 when in its uppermost position, conductor II, released contact M of traffic-governing relay H, conductor I2, the primary of track transformer TT and conductor II back to the mid-tap 9 of the supply winding. The reversed-polarity pulse circuit for this 88 code may be traced from the lower terminal of the referred-to supply winding through conductors 38 and 3I, the coding contact 88 when inits lowermost position, conductor II, released contact I4 of relay H, conductor I2, the primary of transformer TT and conductor I I back to the mid-tap 9 of the supply winding.

In the case of the I20 or caution code, the normal-polarity-pulse circuit extends from the upper terminal of the secondary Winding of transformer 8 through conductors 29 and 32, coding contact I29 in its uppermost position, conductor IE, released contact I4 of traffic-governing relay D, conductor 33, picked-up contact I4 of relay H, conductor I2, the primary of transformer TT and conductor II back to the supply winding mid-tap 9. The reversed-polarity-pulse circuit for this I28 code may be traced from the lower terminal of the referred-to supply winding, through conductors 30 and 3 I, coding contact I20 when in its lowermost position, conductor I6, released contact I4 of relay D, conductor 33, picked-up contact I4 of relay H, conductor I2, the primary of transformer TT and conductor I I back to mid-tap 9.

In the case of the I80 or clear code represented in Fig. 2, the normal-'polarity-pulse circuit extends from. the upper terminal of the secondary of transformer 8 through conductors 29 and 32, the coding contact I80 when in its uppermost position, conductor I5, picked-up contacts Il of relays D and H in series, conductor I2, the primary of transformer TT and conductor I I back to mid-tap 9. The reversed-polarity-pulse circuit for this I80 code may be traced from the lower terminal of the referred to supply winding, through conductor 30, coding contact I89 when in its lowermost position, conductor I5, picked-up contacts I4 of relays D and H in series, conductor I2, the primary of transformer TT and conductor II back to the mid-tap 9 of the secondary of transformer 8.

In addition to selecting the coding of the energy which is supplied tothe track circuit to the rear, the traffic-governing relays H, D and DD at each of the wayside signal locations also control the operation of the associated wayside signal S. This signal control is effected through the mediumof contacts. I8 .and I9.carried by the relays and included in circuits through which the signal lamps are selectively energized from a-suitable source of power, also designated in the diagrams by the terminals B and. C.

When the contacts of all three of the relays H, D and DD are picked up the controlled wayside signal S shows the clear indication of greenover-red. The lighting circuit for the upper green lamp then extends from the supply terminal B through front contacts I9 of all three of the relays in series, conductor 22 and the lamp G back to supply terminal C. The circuit for the lower red lamp similarly extends from terminal B through front contacts I8 of relays H, D and DD in series, conductor 23 and the lamp R back to the terminal C.

When the contacts of relays H and D are picked up and those of relay DD are released the controlled signal S shows the caution indication yellow-over-green. The lighting circuit for the yellow lamp may be traced from the supply terminal B, through front contacts I9 of relays H and D in series, conductor 24 and the lamp Y back to the supply terminal C. The circuit for the lower green lamp extends from terminal B, through front contacts I8 of relays H and Din series, back contact I8 of relay DD, conductor 25 and the lamp G back to the terminal C.

When the contacts of relay H only are picked up and those of relays D and DD are released the wayside signal S displays the slow indication of yellow-over-red. The circuit for the yellow lamp may now be traced from terminal B, through front contact I9 of relay H, back contact IQ of relay D, conductor 24 and the lamp Y back to terminal 0. The circuit for the lower red lamp now extends from terminal B through front contact I8 of relay H, back contact I8 of relay D, conductor 23 and the lamp R back to terminal C.

Finally, when the contacts of all of the traffic governing relays H, D and DD are released, the controlled wayside signal S displays the stop indication of red-over-red. The lighting circuit for the upper red lamp extends from terminal B through back contact I9 of relay H, conductor 25, and the lamp R back to terminal C. The circuit for'the lower red lamp may now be traced from terminal B through back contact I8 of relay I-I, conductor '23 and the lamp R back to. terminal C.

The particular one of the four just described positional combinations which is assumed by the contacts of the traffic-governing relays H, D and DD at each signal location is determined by the character of the energy which is received from the rails I and 2 of the advance track section by the control Winding of the track relay TR at that location. Cooperating with each of these track relays in its control of the associated traffic-governing relays is decoding apparatus in the form of counting-chain relays IR, IRA, 2R, ZRA, 3R, 3RA and 4R and a cycle-registering relay P. The counting-chain relays are arranged to respond distinctively to cycles of the clear, caution and slow trackway codes (represented in Fig. 2) and perform this function by counting the number of normal-polarity energy pulses in each of the code cycles which is received from the trackway. In accordance with that number they set up-for the windings of relays H, D and DD energizing circuits which are selectively and periodically completed by the track relay in a manner explained in a later portion of this specification.

Each of the track relays represented at TR is of an alternating-current two-element two-position type which responds only to normal-polarity energy received from the track rails with which its control winding is shown as being directly connected. This relay distinguishes the polarity of the received energy by comparing it with a measure of the alternating-current voltage of the supply source BC which is constantly impressed upon a local or exciting winding 21. The particular relay shown is provided with a single contact 28 which is sufficiently quick acting in both the pick-up and release directions as to be able to change its position in accurate synchronism with dition during each of the normal-polarity pulses.

of energy which the coding device CT supplies to the track transformer TT from the upper half of the secondary winding of the transformer 8. Finally, when the relay control winding receives energy of the negative or reversed relative in-v stantaneous polarity the contact 28 is merely urged more firmly into its back or released position. This is the condition during each of the reversed-polarity pulses of trackway energy which the coding device CT supplies from the lower half of the secondary winding of the transformer 8.

The cycle-registering relay shown at P is ressponsive to each uninterrupted series of positive or normal-polarity energy pulses of any one of the three of the clear, caution and slow codes which are shown in Fig. 2, and thus serves to register the individual cycles of any of those codes. Each time that the track relay contact 28 is in its picked-up or front position the operating winding of this relay is energized. As shown, this winding'is of the direct-current type and energizing current therefor is supplied from an energy Source, designated by theterminals plus and minus, over a circuit which includes a conductor 36. a r

The contact 34 (and also 35 when used) of relay P is sufficiently slow acting in the releasing or drop-out direction as to bridge the off periods which separate consecutive normal-polarity pulses in all three of the clear, caution and slow trackway codes of Fig. 2.' At the same time the magnitude of this drop-out delay is so limited as not to bridge the intervalwhich is represented by the reversed-polarity pulses of energy which follow each series of normal-polarity pulses and complete, in the case of all of the three named codes, the cycle of which these normalpolarity pulses constitutethe beginning. In practice a release period of the order of second is found to meet both of the above requirements when traffic-governing codes of the illustrative character previously described are used. The value stated is, it will be noted, substantially greater than the second off period (minimum limiting value) of the slow or 80 code and substantially less than the second interval (maximum limiting value) between successive trains or groups of normal-polarity pulses of th I80 or clear code.

At each location of a wayside signal S which guards a track block containing a cut section, such as is occasioned by the highway crossing shown at point La in the blockL-M, a second auxiliary control relay T]? is also utilized for the purpose of controlling the relays XR which govern the operation of the highway crossing signals XS. As will be explained in greater detail in a later portion of the specification, this relay registers the cycles of a fourth or detection code which is represented at the bottom of Fig. 2. Its

operating winding is controlled through a circuit which includes a contact 35 of the repeaterrelayP and it has a period of release delay which is sufficiently greater than that of relayP as to cause its contacts to remain continuously picked-up as j long as a trackway code is received.

At the entrances of track blocks which do not contain cut sections this relayTP is not required,

ence to their individual operation and coordina-' tion and then with reference to the manner in which they cooperate with the associated track relay TR selectively to control the traffic-governing relays H, D and DD.

In the particular counting chain represented,

these relays are arranged in two groups: one, including devices IR, 2R, 3R and 4R, which counts the normal-polarity pulses of energy in each code .cycle; and another group, including relays. IRA,

2RA and 3RA, which registers the intervals which separate these normal-polarity pulses in each cycle of the received code. All of the counting chain relays are shown as having direct-current operating windings which at proper times are supplied with current through pick-up and stick circuits which are connected with a diroot-current supply source, again designated by the terminals plus and minus.

Initial actuation of the counting-chain relays is effected through their pick-up circuits, all of which are controlled by the track relay TR. In

the case of relays IR, 2R, 3R and 4R which count the normal-polarity pulses of each code cycle, each pick-up circuit can be completed only when contact 28 of relay TR is picked up. In addition to this contact 28, the pick-up circuit for relay IR includes serially connected contacts 38 of the remaining six relays in the counting chain; that for relay 2R includes serially connected contacts 39 of relays IR and IRA; that for relay 3R inincludes serially connected contacts 39 of relays IR, IRA, 2R and 2RA; and that for relay 4R includes serially connected contacts 39 of all six of the relays which precede it in the counting chain. e V I In the case of relays IRA, ZRA and 3RA which count the normal-polarity pulse-spacing intervals of each code cycle, each of the pick-up circuits can be completed only when the contact of the track relay TR is released. In addition to this contact 28, the pick-up circuit for relay IRA includes a contact 40 of relay IR; that for relay 2RA includes contacts 40 of relays IR, IRA and 7 2R in series; and that for relay 3RA includes serially-connected contacts 40 of all five of the relays which precede it in the counting chain.

Once the contacts of the counting chain relays are picked up, further or prolonged front closure of these contacts is effected through the beforementioned stick circuits. All of these counting-chain stick circuits are controlled by the cycle-registering or repeater relay P and each can be completed only when contact 34 of that relay is picked up. In each instance, moreover, stick-circuit completion can be effected only when a contact 4| of the counting relay to which the circuit belongs is moved upwardly into engagement with .a cooperating contact 42 and also only when all of the counting relays beyond the given one in the counting chain are deenergized to allow their members 42 to engage with cooperating contacts 43.

The contacts just named are so arranged that as each counting relay actuates, it first sets up its own stick circuit at contact 4| and then breaks the stick circuit for the immediately preceding relay at contact 43. Moreover, the contacts 38, 39 and 49 of these relays are so included in the pick-up circuits of adjacent relays in the actuating sequence that should any one of the relays fail to release its contacts operation of the counting chain beyond that point will be prevented.

For the purpose of controlling the traflic-governing relays H, D and DD, counting-chain relays ER, lRA, 2R, SR .and 4R are provided with additional contacts 44 which form parts of circuits through which the windings of the tramcgoverning relays are selectively supplied with pulses of energizing current. These circuits are more fully described in a later portion of the specification.

In examining the manner in which the counting-chain relays operate, assume first that the contacts of all of the relays in the chain occupy their dropped out or released positions as represented in Fig, 1, that contact 28 of the associated track relay TR is also released, and that the contacts of the cycle-registering relay P are likewise released. These are the conditions which obtain just prior to the beginning of each cycle of any one of the three traffic-governing codes of Fig. 2 which may be received from the trackway.

As the first normal-polarity energy pulse of one of these code cycles is received, track relay TR lifts its contact 28 to the front position and picks up repeater relay P over a circuit which extends from the positive supply terminal, through contact 28, conductor 36, and the winding of relay P back to the negative supply terminal. At the same time, the track relay TR also picks up counting chain relay IR over a circuit which extends from the positive supply terminal, through contact 23, conductors 36 and 46, back contacts 38 of relays 4R, 3RA, 3R, 2RA, 2R and IRA in series, conductor 47 and the winding of relay IR back to the negative supply terminal. In picking up, relay ER locks itself in, by means of contact 4|, over a stick circuit which extends from the positive supply terminal through front contact 34 of relay P, conductor 48, engaged contacts 42 and 43 of relays 4R, 3RA, 3R, 2RA, 2R and IRA in series, engaged contacts 42 and 4| of relay IR, conductor 41 and the winding of relay IR back to the negative supply terminal.

During the first ofi period or pulse-separating interval of the received cycle of traffic-governing code, contact 28 of the track relay TR returns to its released position; the contacts of relay P remain continuously picked up, due to their slow-releasing characteristics (delay of second) which exceed the code off-period length (which is A; or secondsee Fig. 2); and chain relay IR remains picked up under the action of its'own stick circuit. In dropping out at the beginning of this off period, contact 28 of the track relay picks up chain relay IRA over a circuit which may be traced from the positive supplyterminaLthrough the back contact 28, conductc-r i lfrontcontact 48 of relay IR, conductor 5| and the winding of relay IRA' back to the negative supply terminal. As relay IRA picks up, it locks itself in over a stick circuit which extends from the positive supply terminal through front contact 34 of relay P, conductor 48, engaged contacts 12 and 43 of relays 4R, 3RA, 3R, 2RA, and ER in series, engaged contacts 42 and 4| of relay IRA, conductor 5| and the winding of relay IRA back to the negative supply terminal. Due to the resulting interruption of its stick circuit at contact 43 of relay IRA, relay IR now drops out.

As the second normal-polarity energy pulse of the traffic-governing code cycle is received, the track relay TR again picks up contact 28 and supplies the winding of relay P with a second pulse of energizing current. This is received before the release period of relay P has expired and it prolongs the continuous actuation of that relay. At the'same time the track relay also picks up counting relay 2R over a circuit which extends froin the positive supply terminal through front contact 28, conductors 36, 46 and 52, back contact 39 of relay IR, front contact 39 of relay IRA, conductor 53 and the winding of relay 2R back to the negative supply terminal. In actuating, relay 2R first completes its own stick circuit at contact 4| and then interrupts the stick circuit for relay IRA at contact 43, thereby allowing that relay to drop out. The referred to stick circuit for relay 2R extends from the positive supply terminal through front contact 34 of relay P, conductor 48, engaged contacts 42 and 43 of relays 4R, 3RA, 3R and 2RA in series, engaged contacts 42 and 4| of relay 2R, conductor 53 and the winding of relay 2R back to the negative supply terminal.

During the second off period of the received cycle of traffic-governing code, contact 28 of the track relay TR again returns to its released position and picks up chain relay 2RA over a circuit which extends from the positive supply terminal through back contact 28 of relay TR, conductor 49, back contacts 40 of relays IR and IRA in series, front contact 40 of relay 2R, conductor 54 and the winding of relay 2RA back to the negative supply terminal. In actuating, relay 2RA first completes its own stick circuit and then breaks the stick circuit for relay 2R, thereby allowing that relay to drop out. The referred to stick circuit for relay 2RA may be traced from the positive supply terminal through front contact 34 of relay P, conductor 48, engaged contacts 42 and 43 of relays 4R, 3RA and 3R in series, engaged contacts 42 and 4| of relay 2RA, conductor 54 and the winding of relay 2RA back to the negative supply terminal.

The code-following operations on the part of track relay TR which have just been described and the resulting effect upon the chain relays are common to the cycles of all three of the slow, caution and clear codes represented in Fig. 2. From this point, however, the or slow code differs from the other two traffic-governing codes and for this reason it will first be described separately. This description will be followed by an account of what takes place during the remainder of the caution or I20 code and then by an account of what takes place during the remainder of the I or clear code.

'As the first reversed-polarity energy pulse of the 80 or slow code cycle is received, track relay TR still retains its contact 28 in the released position and in other respects the effect is the same as were the second "off periodof this code to be prolonged for another of a second. The condition of the counting chain relays thus remains unchanged and at the expiration offi; of a second from the end'of the second normal-polarity pulse of the code cycle the slow-release cycleregistering relay P releases its contacts. In

moving to the lower position, contact 34 of that relay breaks the stick circuit for counting relay 2RA which also drops out. All of the chain relays are now dropped out, their condition being the same as that assumed for just prior to the beginning of the first normal-polarity energy pulse of the trackway code cycle.

During the third off period of the received cycle of the 80 or slow? code, which period marks the completion of the code cycle, the contact 28 of the track relay TR still remains released. In consequence, the cycle-registering relay P and all of the relays of the counting chain also remain in condition to receive another cycle of traffic-governing code.

The effect of a complete cycle of the. I20 or caution code of Fig. 2 upon the'counting chain apparatus will now be considered. During the first normal-polarity pulse, the first off period, the second normal-polarity pulse and the second off period, the effect or action on the counting chain relays is exactly the same as that for the corresponding portions of the slow or 80 code cycle. That is, during and at the end of the second off period, cycle-registering relay P is picked up and chain relay ZRA is also actuated and locked in through its own stick circuit.

As the third normal-polarity energy pulse of the caution code is received from the trackway, the track relay TR again lifts its contact 28 to the front position and picks up counting relay 3R over a circuit which extends from the positive supply terminal through the contact 28, conductors 35, 46 and 52, back contacts 39 of relays ER, IRA and 2R in series, front contact 39 of relay 2RA, conductor 55 and the winding of relay 3R back to the negative supply terminal. In actuating, relay 3R first completes its own stick circuit at contact 4| and then interrupts the stick circuit for relay ZRA at contact 43, thereby allowing that relay to drop out. The referred to stick circuit for relay 3R may be traced from the positive supply terminal through front contact 34 of relay P, conductor 48, engaged contacts 42 and 43 of relays 4R and 3RA in series, engaged contacts 42 and 4I of relay 3R, conductor 55 and the winding of relay3R back to the negative supply terminal.

During the third off period of the received "caution code cycle, the track relay TR again releases its contact 28 and picks up chain relay 3RA over a circuit which extends from the positive supply terminal through back contact 28 of relay TR, conductor 49, back contacts 40 of relays IR, IRA, 2R and ZRA in series, front contact 40 of relay 3R, conductor 56 and the winding of relay 3RA back to the negative supply termirelay P, conductor '48, engaged contacts 42 and cycle, the cycle-registering relay P releases its contacts due to more than of a second having elapsed since the last normal-polarity pulse of trackway energy. Contact 34 of relay P now breaks the stick circuit for relay 3RA and allows that relay to drop out. All of the chain relays are now dropped out and the decoding apparatus of which they form a part is in condition to receive another code cycle. N

The effect upon the counting chain relays'of a complete cycle of the I88 or clear code, represented at the top of Pig. 2 as consisting of four normal-polarity energy pulses followed by two reversed-polarity pulses, 'will next be considered.

During the first normal-polarity pulse the first off period, the second normal-polarity pulse, the second ofi period, the third normal-polarity pulse and the third off period, the actionson the chain relays are the same as those which have just been described in connection with the corresponding portions of the caution code cycle.

As the fourth positive pulse of this clear code cycle is received from the trackway, the track relay TR again responds, supplies another pulse of energy'to repeater relay P, and picks up chain relay 4R over a circuit'which extends from the positive supply terminal through front contact 28of relay TR, conductors 5's, .6 and 52, back contacts 39 of relays IR, IRA, 2R, 2RA and 3R in series, front contact 39 of relay 3RA, condu-ctor 57 and the winding of relay 4R back to the negative supply terminal. In actuatingrelay 4R completes its own stick circuit at contact 4! and then interrupts the stick circuit for relay 3RA at contact 43, thereby allowing that relay to drop out. The referred tostick circuit for relay 4R extends from the positive supply terminal through front contact 34 of relay P, conductor 48, engaged contacts 42'and 4| of relay 4R, conductor 51, and the winding of relay 4R back to the negative supply terminal.

During the fourth 01f period of the clear or I 8! code cycle, track relay TR again drops out. Aside, however, from the interruption of the energizing circuit for relay P, no other action takes place during this period. As the first being received, the cycle-registering relay P releases its contacts due to more than of a second having elapsed from the end of the last pulse of normal-polarity energy. Contact 34 of that relay now breaks the holding circuit for chain relay 4R and that relay accordingly drops out. During the sixth and final off period of the clear code cycle, all of the chain relays continue in their contact-released conditions and the decoding apparatus of which they form a part is again ready to receive and respond to another cycle of trackway code.

From the foregoing it will be seen that the code-following track relay TR functions to energize the counting-chain relays in sequence during each of the trafiic governing code cycles of trackway energy which it receives from the trackway and that the counting relays, in turn, decipher each received cycle by registering the number of normal-polarity pulses which it contains. Thus if there are two of these per cycle, as in the case of the slow or 80 code, chain relay 2R picks up its contacts; if there are three, as in the case of the caution or I20 code, relay 3R picks up its contacts; and if there are four, as .in the case of the clear or I89 code, chain relay 4R picks up it's contacts.

It will also be seen that the pulses of reversedpolarity energy which follow each series of norrnal-polarity pulses have the effect of allowing the relay counting chain to return to normal so that it is prepared to receive the next series of normal-polarity pulses. From this it will further be apparent that the efiect produced on the 4 counting chain by these reversed-polarity pulses might also be produced by using a simple time interval of corresponding total length between each series of normal-polarity pulses. However, for reasons to later be discussed in greater detail in connection with the operation of train-carried cab signaling equipment controlled through the medium of the usual frequency type of decoder, it is preferred to employ the pulses of reverse polarity in the manner already explained in connection with the code-cycle representations of Fig. 2.

The manner in which the chain relays control the tr-afiic-governing relays H, D and DD will now be explained. In the illustrative arrangement shown, relay H responds to cycles of received trackway code of any one of the slow, caution and clear varities of Fig. 2; relay D responds to cycles of the caution and the clear codes only; and relay DD responds to cycles of the clear or I80 code only.

Each of these trafiic-governing relays is of the slow-releasing type and is represented as having a direct-current operating winding adapted to be supplied with energizing current through a circuit which is shown as being connected with a direct-current supply source, again designated by the terminals plus and minus. In operation of each relay, even a very short pulse of energizing current serves to pick-up the cont-acts (I4, I 8 and I9) thereof, which continue tooccupy their front position for the full release period of the relay after the actuating current is interrupted. If, of course, within this release period another pulse of energizing current is supplied, the time of contact-closure is prolonged for another release period and the contacts then do not drop out until that further period has expired.

As has been pointed out, control of the trafiicgoverning relays is effected through the medium of contacts 44 carried by the counting chain relays IR, IRA, 2R, 3R and 4R. The pick-up or energizing circuit for relay H is carried through contact 44 of relay 2R and can be completed only when that contact is picked up and the contacts of relays IR and IRA are released. Likewise, the energizing circuit for traffic-governing relay D is carried through contact 44 of relay 3R and it can be completed only when that contact is picked up and the contacts of relays 2R, IRA and IR are released. And finally, the energizing circuit for relay DD is carried through contact 44 of chain relay 4R and it can be completed only when that contact is picked up and the contacts of relays 3R, 2R, IRA and IR are released.

All of the energizing circuits for the trafficgoverning relays are, in addition, dependent for their completion upon contact 28 of the track relay TR occupying its front or picked-up position. Moreover, the before-mentioned slow-release characteristics of each relay are selected to be slightly in excess of the cycle lengths of the particular traffic-governing codes to which that relay responds in order that it may bridge the gaps between the normal-polarity pulses of successive cycles. Thus in the case of relay H which responds to all three of the slow, caution and clear codes, the longest cycles of which are 2%, seconds in length, the release period is preferably of the order of about 2 seconds. In the case of traffic-governing relay D which responds only to the caution and the clear codes, for both of which the cycle lengths are 2 seconds, the release period is preferably of the order of 2%, seconds. And in the case of traffic-governing relay DD which responds only to the clear or I 80 code having cycles of 2 sec onds duration, a release period of 2 seconds is similarly provided.

The manner in which the just described energizing circuits for the trafiic-governing relays H, D and DD are selectively completed will now be explained. If the slow or 86 code is being received from the trackway, relay TR picks up, releases, again picks up and then stays released for three periods during each cycle of this code, this operation repeating itself as long as the named code continues to be received. Cycleregistering relay P responds to this operation, it staying picked up between successive pick-ups on the part of relay TR and dropping out after each pair thereof or between successive code cycles. On the first front contact closure of relay TR chain relay IR picks up; on the first release of the track relay contact, chain relay IRA picks up; and on the second front closure of the track relay contact, chain relay 2R picks up.

Each time that relay 2R is thus actuated, en.- ergizing current is supplied to the winding of traffic-governing relay H through a circuit which extends from the positive supply terminal, through front contact 28 of relay TR, conductors 3'6, 46 and 52, back contact 44 of relay IR, conductor 6|, (also front contact 59 of relay TP and conductor I3 in Fig. la) back contact 44 of relay IRA, front contact 44 of relay 2R, conductor 62, and the winding of relay H back to the negative supply terminal. Due to its slow release characteristics relay H bridges successive cycles of the slow or 80 code and thus maintains its contacts continuously picked up as long as that code is received from the trackway.

When the caution or I20 code is received, the track relay TR picks up, releases, picks up, releases, and picks up and then releases and stays cessive code cycles.

released for three successive periods during each cycle of that code.

ing of traffic-governing relay H receives current through the circuit just traced and thus maintains its contacts continuously picked up as long as the caution code is received. Each time that chain relay 3R closes its front contacts, the winding of traffic-governing relay D likewise receives a pulse of energizing current through a circuit which may be traced from the positive supply terminal through front contact 28 of relay TR, conductors 36, 46 and 52, back contacts 44 of relays IR, IRA (interconnected in Fig. 1b by conductor 6|; in Fig. ill, by conductor 6|, front contact 59 of relay TP and conductor 13) and 2R in series, front contact 44 of relay 3R, conductor 63, and the winding of relay D back to the negative supply terminal. Due to its slow'release characteristics relay D also maintains its contacts continuously picked up as long as the caution 7 code is received from the trackway.

When the clear or I80 code is received from 7 the trackway, relay TR picks up, releases, picks up, releases, picks up, releases, picks up and then releases and stays released for five periods during each cycle of that code. The repeater relay P maintains its contacts picked up during each series of the four pick-up operations on the part of relay TR and releases them after each series or between succesive code cycles. On the first pick-up operation by relay TR chain relay IR picks up; on the second chain relay 2R picks up; on the third chain relay 3R picks up; and on the fourth chain relay 4R picks up.

Each time relay 2R thus is energized the winding of traffic-governing relay H receives a pulse of energizing current; each time that relay 3R picks up the winding of traffic-governing relay D receives an energizing pulse; and each time that relay 4R picks up the winding of traffic-governing relay DD likewise receives an energizing pulse. The pick-up circuits for relays H and D are the same as those traced above. In the case of relay DD the circuit extends from the positive supply terminal through front contact 28 of relay TR, conductors 3'6, 46 and 52, back contacts 44 of relay IR, IRA (interconnected in Fig. 11) by conductor 6I; in Fig. 1a by conductor 6 I front contact 59 of relay TP and conductor 13), 2R and 3R in series, front contact 44 of relay 4R, conductor 64 and the winding of relay DD back to the negative supply terminal. Due to their slow release characteristics all three of these trafiic-governing relays H, D and DD continuously maintain their contacts picked up as long as the clear code is received from the trackway.

When no energy is received from the trackway, contact 28 of track relay TR remains in the released position, the contacts of all seven of the counting chain relays IR to 4R are likewise dropped out, and all three of the traffic-governing relays H, D and DD also allow their contacts to occupy the released positions.= This comes about from the fact that their pick-up circuits are respectively broken at the contacts 44 of relays 2R, 3R and 4R which are, under the conditions stated, continuously released.

The equipment so far described is that which is associated with track blocks which do not contain cut sections and of which the apparatus represented at location M in Fig. 1b is representative. It is to be noted that no line conductors are required between the equipment at the entrance ends of successive blocks not containing cut sections, the only medium of inter-connection being the track circuit of which the trafiicrails I and 2 form a part.

When, however, a block includes, as does that shown at LM, a cut section of the character defined by location La, certain additional equipment is required. As represented in association with location La, this supplemental equipment includes provision for repeating the trackway code around the insulated joints 3 of the cut section, a coding device CTa; for supplying the rear track circuit with energy of the special detection code previously referred to, and relays XR and associated means for controlling the highway-crossing signals XS.

The code-repeating provisions will first be described. As shown at location La, these take the form of a track transformer TTa connected with the rails of track section LLa, a supply transformer B constantly energized from the alternating current source BC and having a secondary winding provided with normal and reversed polarity energy-supply sections, and a pair of track relays TRN and TRR' connected with the rails at the entrance end of the section LaM and provided with contacts 66 through which either the normal or the reversed polarity sec tion of the supply winding may be connected with the primary of the track transformer TTa through the medium of conductor I2 and a contact 61 of a relay TPa.

Track relay TRN is substantially a duplicate of the device TR at locations L and M and is arranged to pick up its contacts when the control winding thereof'receives trackway energy which has a normal relative instantaneous polarity with respect to the voltage from source B-C which constantly energizes with the exciting winding 2! of the relay. At all other times the relay contacts 28 and B6 occupy the released position. The second track relay TRR is of similar construction and characteristics. It differs from the first, however, in being arranged, as by a reversal of the supply connection for the exciting winding 21, to pick up its contacts in response to trackway energy of reversed relative instantaneous polarity and to allow the contacts to remain in the released position at all other times.

In operation, relay TRN follows the normalpolarity pulses of coded energy which are transmitted thereto by the rails of track section Liz- N, while relay TRR similarly follows the reversedpolarity pulses which'are impressed upon its control winding. Hence, as long as the rails of the forward track section LaM transmit no energy to these two track relays, the contacts of both occupy their dropped out positions and the supply transformer 8 then is disconnected from the track transformer TTa. at contacts 66. Under this condition no energy is supplied to the track section L-La to the rear.

However, upon the occasion of each normalpolarity pulse of energy received by the relays TRN and TRR at location La, relay 'IRN picks up its contacts and relay 'I'RR tends to move its contacts further downwardly. Contact 65 of relay TRN now connects the primary of track transformer T'Ia with the upper half of the secondary winding of supply transformer 8 and completes a rail-supply circuit which extends from the upper terminal of the secondary of transformer 8 through conductor 29, front contact 66 of relay TRN, conductor 68, front contact 67 of relay TPa, conductor 12, the primary of track transformer TTa, and conductor I! back to the mid-tap 9 of the supply winding. Through this circuit the track section to the rear of location La is supplied with normal-polarity energy as long as the contacts of track relay TRN remain picked p.

Similarly, when the forward section transmits alternating current energy of the reversed polarity, track relay TRR responds and picks up its contacts, thereby completing at contact 66 a circuit through which the track transformer TTa is connected with the lower half of the secondary winding of the supply transformer 8. This circuit may be traced from the lower terminal of the supply winding through conductor 30, front contact 66 of relay TRR, conductor 68, front contact B7 of relay TPa, conductor l2, the primary of track transformer TTa, and conductor ll back to the mid-tap 9 of the supply winding. Through it the track section to the rear of location La is supplied with reversed-polarity energy as long as the contacts of track relay 'IRR remain picked up.

In this manner, the coded energy which is received from the rails of track section La-M is at all times repeated in the rear section L-La, not only as to on and off periods of the code but also as to the relative instantaneous polarity of the voltage of which each energy pulse of this code is made up. Insofar, therefore, as the effect upon the equipment at location L by energy supplied to the rails through track transformer TT at location M is concerned, each one of the codes shown in Fig. 2 is repeated around the cut section La and thus transmitted to location L in the same manner as were rails between points L and M in the form of the continuous conductors of the track blocks which do not contain cut sections.

The manner in which the highway crossing signals XS associated with the cut section La are controlled will now be described. In the scheme shown, two relays XRi and XR2 are utilized jointly to control the completion of the highway signal operating circuit and thus determine the operation of the crossing protective signals. Each of these relays is provided with a contact 69 through which operating energy may be supplied to the signals. Through the medium of a pawl device (not shown), these contacts are so interlocked mechanically that only one of them may occupy its downward or circuit-completing position at any particular time. Moreover, this pawl operates further to require that following a contact release on the part of either of the relays XR the winding of the companion relay must be energized before the contact of that relay can be released to its circuit-closing position.

Normally the windings of both of these relays receive energizing current through circuits which respectively include contacts "H and 12 of relays TP and TPa at locations L and La and thus hold the contacts 69 in the picked-up positions represented. Under such conditions the crossing signals XS do not operate. When, however, either of these two circuits is interrupted, the affected relay XR releases its contact 69 and thereby brings the crossing signals XS into operation.

Also forming a part of the crossing-signal control apparatus at location L is the previously mentioned special cycle-registering relay TP. It is of the delayed-release type and in the scheme disclosed it is arranged to hold its contacts in their picked-up position for a period, following each pulse of energizing current received by its operating winding, which exceeds the relatively wide spacing between consecutive energy pulses of the detection code which is represented at the bottom of Fig. 2. Whenever not only this detection code but also any one of the three trafl'lc-governing codes also represented in Fig. 2 is received from the trackway by the track relay TR at location L, this slow-release relay TP maintains its contacts continuously picked-up and thereby supplies energy to relay XRI.

This continuous closure of the front contacts of relay TP results from a joint action of the cycleregistering relay P and the counting-chain relay IRA, which action will now be explained. Following each pulse of normal-polarity energy, relay P holds its contacts in the picked-up position for about of a second and thus sets up, at contact 35, the pick-up circuit for relay TP. Also following each of these normal-polarity pulses,

counting chain relay RA picks up, in the manner previously explained, and thus completes, at contact M, the just referred to pick-up circuit which extends from the positive supply terminal through back contact 28 of relay TR, conductor t9, front contact 35 of relay P, conductor 15, front contact of relay IRA, conductor 16 and the winding of relay TP back to the negative supply terminal.

As long, in consequence, as the above circuit completion repeats itself at intervals not exceeding those determined by the pulse spacings of the detection code shown in 2, the cycleregistering relay TP at location L holds its contacts picked-up continuously, this action being made possible by the before described slowreleasing characteristics of the relay. Under other conditions, of course, as when the track section L-La is occupied by a train, relay TP releases its contacts.

A corresponding relay TPa, also of the slowreleasing type, is installed at the cut-section location La and arranged to control the energization of relay XRZ. Energizing current is supplied to the winding of this relay TPa through the contact 28 of either of the relays TRN and TRR. That is, in responding to each normalpolarity pulse of trackway energy, relay TRN completes an actuating circuit for relay TPa which may be traced from the positive supply terminal, through front contact 28, conductor Ti and the winding of relay TPa back to the negative supply terminal. Likewise, in responding to each reversed polarity pulse of coded trackway energy, contact 28 of relay TRR completes an equivalent energizing circuit for the relay TPa.

This relay 'IPa has a contact-release period which is somewhat in excess of the longest off period of any of the three traffic-governing codes which may be received at location La. Whenever, therefore, this received energy is of the slow, caution or clear code represented in Fig. 2, relay TPa holds its contacts continuously picked up, due to the reception by its winding of the spaced energizing pulses previously described. Under other conditions, of course, as when a train is in the section LaM to by-pass the coded energy supplied to the rails thereof, the relay releases its contacts.

Also installed at location La and aiding in the control of the crossing signals XS is a special coding device CTa which comes into action at proper times to silence these signals. This code transmitter CTa is represented as being of the constantly-operating type and has a coding contact 2E and operating means therefor which cooperate in producing the previously referred to clearing or detection code represented at the bottom of Fig. 2.

This detection code is of a distinctive character which does not cause response of the wayside signal S at location L or of cab-signals on a following train which may have overrun that location, and yet it is effective to act upon the relay apparatus at location L in a manner which stops operation of the crossing signals XS. The particular code illustratively shown at the bottom of Fig. 2 consists of a relatively short on period followed by a relatively long off period, these periods being repeated successively. It mayconveniently be produced by contact operating mechanism of the character represented at the bottom of Fig. 3 in asociation 'mal-polarity energy followed by a much longer spacing interval.

Whenever the advance section LaM is occupied by a train, energy pulses of the detection code are suppliedfrom the transformer 8 to the track transformer TTa and thence to the rails of the track section to the rear of location La. Under the condition stated, relays TRN and TRR are both deenergized and contacts of relay TPa are also dropped out. Contact 20 of device CTa now periodically completes a rail-supply circuit which extends from the upper terminal of the secondary winding of transformer 8 through con-i 'ductors 29 and I8, coding contact 20, conductor I9, back contact 61 of relay 'I'Pa, conductor I2, the primary winding of transformer T'Ia and conductor I I back to the mid-tap 9 of the supply winding.

The effect of the detection code upon the relay apparatus at location L will now be considered. As each pulse (which is of normal polarity) of this code is received from the trackway, track relay TR responds and simultaneously picks up repeater relay P and chain relay IR. Relay IR locks itself in, while relay P holds its contacts picked up during the pulse andfor of a second thereafter. At the end of the pulse,

relay TR releases its contact 28 and picks up chain relay IRA which locks itself in. Contact 14 thereof now picks up relay TP by completing the before-traced energizing circuit for the Wind-.

way crossing signals. XS is prevented by virtue of contact 69 of relay XRI also being picked up. 7

Under the stated conditions, moreover, the contacts of all three of the trafiic-governing relays H, D and DD at locattion L are released and the controlled signal SI accordingly shows stop. This continuously deenergized condition of the traffic-governing relays results from the fact that the widely spaced energy pulses of the detection code, impressed upon the track circuit of the cut section L-La by device CTa, are ineffective to pick up any of the counting chain relays above IR and IRA at location L. In so far as relays. H, D and DD are concerned, therefore, the effect is the same as were no energy at all to be received from the trackway.

In operation of the complete highway crossing signal control system herein disclosed, as long as both of the track sections LLa and La-M are vacant the signals XS are inactive. When, however, a train approaches location La from either direction these signals are brought into operation and continue active until the. train either clears that location or withdraws from the track section by which it approached.

In examining this operation, assume first that a train proceeding along track l-2 in the authorized direction of the arrows enters section Ir-Lll. Relay TR at location L releases its concode from location La to location L. There this picks up the contact of track relay TR once every 3 seconds and effects, in the manner already described, energization of relays TP and XRI to discontinue operation of the crossing protective signals XS. Even though the second interlocked relay XR2 remains deenergized While the train continues through the advance section LaM, that relay does not close the operating circuit'of the crossing signals XS for the reason that the before-described interlocking pawl now functions mechanically to hold the contact 69 thereof out of engagement with its back point.

When the forward moving train clears the exit end of this advance section La-M, energy of one or another of the clear, caution and slow codes is received at location La and repeated by relays TRN and TRR in the rear section L-La;

the contacts of relay TPa are picked up under the control of this repeated energy; and the energizing circuit for relay XR2 is again, completed. Under these conditions the interlocking V pawl returns to a neutral position which allows either one of the two relays XRI, if subsequently deenergized, selectively to drop its. contact 69 to the circuit-closing position and again place the crossing signalsXS in operation.

Consider next that a train going in the reverse direction backs into the exit end of track section LaM. At location La, relays TRN and TRR. now release their contacts, as does also relay TPa upon the expiration of its. delayed-release period. Contact I2 thereof breaks the energizing circuit of relay XR2 which, in turn, places the crossingprotective signals XS in operation. This opera- 7 5 tion continues as long as any part of the named train remains in section LaM.

As soon as the reverse-moving train backs out of the entrance end of section La-M, the rails of that section again transmit coded energy from location M to location La. There this is responded to by relays TRN and TRR which effect the energization of relay TPa. In consequence, operation of the crossing protective signals XS is now discontinued by relay XR2. Even though the companion relay XRJ remains dcenergized while the train is in track section LLa, contact 69 of that relaydoes not drop to its circuit-closing position for the reason that the interlocking pawl now holds that contact out of engagement with its back point.

Should the reverse-moving train clear the entrance end of this rear section LLa, one or another of the traffic-governing codes is then received at location L, the contacts of relay TP are again picked up, and theenergizingcircuit for relay XRI is once more completed. This returns the interlocking pawl to its before-described neutral position.

The Various component parts of my improved signaling apparatus having been described, attention will now be directed to the manner of operation of the complete system shown in the diagram of Figs. la-b. To facilitate a description of this operation, the diagram of Fig. 4 has been prepared and will be referred to as the description proceeds. In it, the track |2 of Figs. la-b is represented as extending for three blocks (identified with locations K, J and I) behind the wayside signal location L, and a train V is shown as occupying the portion of the signal block LM immediately ahead of the cut section La.

Under these conditions, and further assuming that at least three blocks ahead of section La.1VI are clear, the wayside apparatus at location M receives trackway energy of the clear code reprepresented at the top of Fg. 2, the track relay TR. follows the normal-polaritypulses of this code, cycle-registering relay TP holds its contacts in the picked-up position, the contacts of all three of the traffic-governing relays H, D and DD are picked up and the signal Sm shows the clear indication of green-over-red.

At the cut-section location La immediately behind the train V, the contacts of both of the track relays TRN and TRR, are released, as are also those of relay TPa. This results from the by-passing through the train wheels and axles of the energy which is supplied to the track rails by the track transformer TT at location M. Under the conditions stated, coding device CTa supplies the rails of section LLa with energy of the detection code represented at the bottom of Fig. 2.

At location L this energy momentarily picks up the contact of track relay TR every 3 seconds, causes relay TP to hold its contact continuously picked up, and keeps the highway crossing signals XS at location La from operating. As the detection code is ineffective for causing pick-up current to be supplied to the traffic-governing relays H, D and DD, the contacts of all three of these relays accordingly remain released. This causes the wayside signal SI to display the stop indication of red-over-red and the associated code transmitter CT to supply the rails of section K-L with energy of the slow or 80 pulse per minuite code. I

At location K the track relay TR follows the normal-polarity pulses of this energyrthe contacts of traffic-governing relay H are picked up and those of relays D and DD are released. In consequence, the wayside signal Sic shows the slow indication of yellow-over-red and the rails of track section JK are supplied with energy of the caution or 120 pulse per minute code. At location J the track relay TR follows the normal-polarity pulses of this code, the contracts of traffic-governing relays H and D are picked up and those of relay DD are released. As a result the signal Sy' controlled thereby shows the caution indication of yellow-over-green and the rails of section I-J are supplied with energy of the clear or 180 pulse per minute code.

At location I track relay TR follows the normalpolarity pulses of this code and causes the contacts of all three of the trafiic-governing relays H, D and DD tobe picked up. Under this condition the wayside signal S1 shows the clear indication of green-over-red and the rails of the track section to the immediate rear are supplied with energy of the clear code. At each of the succeeding locations to the rear which are associated with vacant track sections, the just-described conditions for the apparatus at location I are repeated.

In addition to providing the just-described advantageous form of wayside signal control, the frequency-polarized trackway codes used in my improved system make it possible for train-carried cab-signaling equipment utilizing the usual frequency type of decoders to respond to the trackway energy in exactly the same manner as were the conventional frequency codes (consisting of normal-polarity pulses only) to be supplied to the track rails. Train-carried cab signaling and/or brake control equipments of the type referred to are well known in the art and the circuits of one illustrative form thereof are represented in Fig. 5.

This typical cab-signaling equipment of Fig. 5 is generally equivalent to that shown and described in United States Patent No. 1,773,472 to Paul N. Bossart, which issued August 19, 1930, from an application Serial No. 166,407, filed February 7, 1927, and assigned to The Union Switch 8!. Signal Co. It makes use of pick-up windings 85 and 86 mounted on the locomotive from, an amplifier 81 which strengthens the energy inductively received from the track rails i and 2 by these windings, a master or code-following relay MR which is energized by a measure of the output of this amplifier and which responds to each pulse of the trackway energy regardless of its relative instantaneous polarity, a decoding transformer DT which is supplied under the control of. the master relay with code-following pulses of primary current, decoding relays DRl8ilDRl2il and DRI-I which are connected with the decoding transformer through frequency-selective circuits B9 and which selectively respond in accordance with the frequency of the voltage appearing in the transformer secondary, and a cab signal CS V' in the section LaM. Of this signal CS, the top unit or lamp is assumed to designate fullauthorized speed, the second lamp from the top caution'speed, the third slow speed and the fourth the most restrictive or stop indication.

When the following or signal-carrying train referred to above is receiving the clear code of Fig. 2, both the positive or normal-polarity and the negative or reverse-polarity pulses of this code have the same eifect upon the frequency-selecv.tive decoding apparatus on the'train and in consequence the two decoding relays DR|80 and DRH'which respond to trackway energy pulses of the I80 code rate pick uptheir contacts and complete the energizing circuit for the top lamp of the signal CS. Whenthe train is in a section supplied with energy of the caution code of Fig. 2, its decoding apparatus again responds in the same manner as were all of the uniformly spaced energy pulses to be of the same relative polarity and the decoding relays DRI20 and DRH then respond and complete the energizing circuit for the second or caution lamp of the cab signal. When the signal-carrying train is in a section supplied with trackway energy of the slow code shown in Fig. 2, the decoding apparatusresponds to the 80 pulse per minute rate and the decoding relay DRH only now responds and completes the energizing circuit for the third or slow lamp. Finally, when the train-carried apparatus receives uncoded trackway energy, or no energy at all, all three of the decoding relays'DR drop out and the most restrictive or stop lamp of the cab signal is then lighted.

Train-carried apparatus of the character under consideration. is, moreover, unresponsive to the detection code shown at the bottom of Fig. 2. Because of the very wide separation of the energy pulses of this code, their effect upon the apparatus is the same as were no energy to be received from'the trackway. That is, even though the master relay MR on the train follows these pulses, the short periods of energization which it causes to be supplied to thedecoding transformer DT are so widely spaced that none of the decoding relays can respond thereto and the stop lamp of the cab signal accordingly remains lighted.

From the foregoing it will be seen that the improved organization of the trackway apparatus of my invention provides all of the advantages which are incident to previous coded wayside and cab-signal systems. That is, the indicating means of my new system are immune to foreign current, no line conductors are needed to obtain automatic block signaling and no reset or approach-energization problems are involved. Be- 7 cause of its use of two element two-position track relays, protection against broken-down rail joints may be made inherent. Moreover, the system is equally applicable to automatic signal blocks which both do and do not contain cut sections and in case out sections are present clearance thereof by a detection code may be effected without in In fact, the counting chain Hence, although I have herein shown and described only one form of railway traflic 'controlling apparatus embodying my invention, it will be understood that various changes and modification 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 section of railway track,

means for supplying the rails of said section with recurring cycles of oneor another of a plurality of difierent code pulse combinations each of which is made up of spaced pulses of normal-polarity energy in distinctive number followed by reversed-polarity energy in similar pulse form, means for selectively determining which of said different code pulse combinations is supplied to said rails, a track relay connected to said rails and arranged to respond only to the normal-polarity pulses of said coded energy which are received therefrom, decoding means governed by said track relay and arranged to register the number of responses which that relay makes during each code cycle, traffic-governing relays arranged to be energized selectively in accordance with the number of registrations which said decoding means make during each cycle of received code energy, and signalling apparatus controlled by said trafiic governing relays.

2. In combination, a section of railway track, means for supplying the railsof said section with recurring cycles of one or another of a plurality of different code pulse combinations each of which is made up of spaced pulses of normal-polarity energy in distinctive number followed by reversed-polarity energy in similar pulse form,

means for selectively determining which of said' and arranged to respond only to the normal polarity pulses of said coded energy which are received therefrom, a chain of counting relays arranged to register in sequence the number of responses which said track relay makes during each received code cycle, a cycle-registering relay responsive to the series of normal-polarity pulses in each cycle and arranged to return said relay counting chain to a pre-registration condition during the reversed-polarity portion of each cycle, traffic-governing relays, circuits controlled jointly by said track and counting-chain relays for selectively energizing said traffic-governing relays in accordance with the number of registrations which said counting relays make during each cycle of received code energy, and signalling apparatus controlled by said trafiic governing relays.

3. In a railway signaling system, the combination of means for producing recurring cycles of a plurality of different code pulse combinations each of which is made up of spaced pulses of normal polarity energy in distinctive number followed by reversed-polarity energy in similar pulse form, a track relay responsive only to the normal-polarity energy, means for selectively supplying said track relay with energy cycles of one or another of said diiferent code pulse combinations, a plurality of traffic-governing relays having slow release periods sufficient to span the time between corresponding pulses in. recurrent cycles of the received code, signalling apparatus controlled by said traffic governing relays, and. means for sequentially actuating a variable number of said traffic-governing relays in accordance with the number of responses which said track relay makes during each received code cycle, said means comprising a chain of counting relays arranged to register said responses, a cycle-responsive relay arranged to return said counting chain to a pre-registration condition after each response series, and energizing circuits for the trafiic-governing relays controlled jointly by said track and counting chain relays.

4. In a. railway signaling system, a trafiic track, means for supplying said track with recurring cycles of one or another of a plurality of different code pulse combinations each of which is made up of a distinctive number of normalpolarity pulses separated by time intervals and followed by a time interval together with reversed-polarity energy in similar pulse form, means for selecting which of said different code pulse combinations is supplied to said track, a track relay connected to receive said coded energy from said track and arranged to pick up upon each normal-polarity pulse of that energy and to remain dropped out at all other times, a plurality of counting relays controlled by said track relay and arranged to register in sequential order each pick-up and each drop-out operation thereof, trafl'lc governing means controlled by said counting relays, and a cycle-registering relay for returning said counting relays to a preregistration condition after each cycle-series of normal-polarity pulse responses of said track relay, said cycle-registering relay receiving energy upon each pick-up operation of the track relay and having a slow release period sufiicient to bridge the individual spacing intervals in the code cycles but not the combined time represented by the reversed-polarity pulses and their associated intervals which constitute the latter portion of each cycle.

' 5. In a railway signaling system, a traffic track, means for supplying said track with recurring cycles of one or another of a plurality of different code pulse combinations each of which is made up or" a distinctive number of normal-polarity pulses separated by time intervls and followed by a time interval and reversed-polarity energy in similar pulse form, means for selecting which of said different code pulse combinations which is supplied to said track, a track relay connected to receive said coded energy from said track and arranged to pick up upon each normal-polarity pulse of that energy and to remain dropped out at all other times, a chain of relays adapted to be energized and deenergized in sequence and consisting of two groups arranged in alternation, circuits completed when said track relay is picked up for causing the relays of one of said groups to register the number of normal-polarity pulses in each cycle of coded energy, other circuits completed when said track relay is dropped out for causing the relays of said other group to register the number of time periods in each cycle which separate normal-polarity pulses, a slow-release cycle-registering relay receiving energy upon each pick-up operation of the track relay and acting to return said chain relays to a pre-registration condition after each cycle series of normal-polarity pulses, and traific governing means controlled by said chain relays.

6. In combination, a first and a second section of railway track, means for supplying the rails of said first section with spaced pulses of both normal and reversed-polarity energy, a first polar relay receiving said energy from said rails and responsive only to the normal-polarity Pulses thereof, a second polar relay also receiving said energy from said rails but responsive only to the reversed-polarity pulses thereof, a circuit through which energy may be supplied to the rails of said second track section, sources of normal and reversed-polarity energy, a contact carried by said first polar relay for connecting said rail-supply circuit to said normal-polarity source upon each response of that relay, and a contact carried by said second polar relay for connecting said railsupply circuit to said reversed-polarity source upon each response of that relay.

7. In combination, a first and a second section of railway track, a first and a second codefol lowing polar relay connected to the rails of said first section and respectively responsive to normal and reversed-polarity energy pulses which may be received therefrom, a circuit through which energy may be supplied to the rails of said second track section, a source of energy, a coding device having a contact which periodically establishes connection with said source in a manner to produce recurring code cycles each consisting of a connection period followed by a much. longer spacing interval, a slow-release relay jointly controlled by said two polar relays, and means including said slow-release relay for connecting said rail-supply circuit Whenever both of said polar relays remain inactive for the prolonged period which accompanies the presence of a train in said first track section.

8. In combination, a first and a second section of railway track, a first and a second code-following polar relay connected to the rails of said first section and respectively responsive to normal and reversed polarity energy pulses which may be received therefrom, a circuit through which energy may be supplied to the rails of said second track section, a source of energy, a coding device having a contact which periodically establishes connection with, said source in a manner to produce recurring code cycles each consisting of a connection period followed by a much longer spacing interval, a slow-release relay having a contact which in its dropped out position connects said rail supply circuit with said energy source over said coding contact, and contacts carried by said polar relays and arranged to sup ply pick-up current to said slow-release relay whenever either of said polar relays is picked up.

9. In combination, a first and a second section of railway track, a first and a second code-following polar relay connected to the rails of said first section and respectively responsive to normal and reversed-polarity energy which may be received therefrom, a circuit through which energy may be supplied to the rails of said second track section, sources of normal and reversedpolarity energy, contacts carried by said and second polar relays for connecting said railsupply circuit respectively to said normal and reversed polarity sources upon each respective response of the polar relays whereby to repeat into the rails of said second section each pulse of both normal and reversed-polarity energy which may be received from the rails of said first section, a coding device having a contact which periodically establishes connection with said normal-polarity source in a manner to produce recurring code cycles each consisting of a connection period followed by a much longer spacing interval, and a slow-release relay jointly controlled by said two polar relays and arranged to connect said rail-supply circuit with said energy source'over said coding contact whenever'both of said polar relays remain dropped out for the prolonged period which accompanies the presence of a train in said first track section.

10. In combination, two consecutive sections of railway track, highway crossing protective apparatus positioned adjacent the point of division between said track sections, a relay arranged when unenergized to place said protective apparatus in operation, a slow-release relay arranged when picked up to supply energizing current to said operation-governing relay, and a pair of code-following polar relays connected to the rails of one of said track sections and respectively arranged to supply picked-up current to said slowrelease relay whenever energy of normal or reversed relative polarity is received from said rails, I

11. In combination; a first and a second section of railway track, means for supplying the rails of said first'section with pulses of coded energy which regularly recur and which are separated by time intervals of relatively short dura tion, means for repeating said pulses into the rails of said second section, means effective when no energy is received from the rails of said first section for supplying the rails of said second section with recurring code cycles each consisting of an energy pulse followed by a relatively long spacing interval which longer interval substantially exceeds the said relatively short intervals that separate the said pulses of coded energy which are suppliedeto the first section, highway crossing protective apparatus located adjacent the point or" division between said track sections, a relay arranged when unenergized to place said apparatus in operation, a slow-release relay ar ranged when picked up to supply energizing current to said operation-governing relay, and means controlled by coded energy received from the rails of said second section for maintaining said slow-release relay continuously picked up as long as the pulses of such received energy recur at intervals which do not exceed the said relatively long spacing interval of the above-described code cycle.

12. In combination, a section of railway track, means at the exit end of said section efiective at times to supply the rails thereof with recurring pulses of energy which are spaced comparatively closely and in accordance with one or another of a plurality of difierent trams-governing code patterns, means also at said section exit effective at other times to supply said rails with recurring energy pulses which are spaced comparatively widely and in accordance with a detection code pattern, traffic-governing apparatus at the en said detection code pulses and. arranged when picked up to supply energizing current to said operation-governing relay, and means responsive to pulses of both the detection and the trafficgoverning codes which may be received from said rails for supplying said slow-release relay with pulses of pick-up current which recur at intervals less than the release period of that relay.

13. In combination with a section of railway track, means at the exit end of said section for supplying the rails thereof with recurring cycles of one or another of a plurality of different codepulse combinations each consisting of a predetermined number of normal-polarity energy pulses which recur at a predetermined rate and which are separated by time intervals and followed by a tim interval together with reversed-polarity energy in similar pulse form, means for selectively determining which of said different code pulse combinations is supplied to said rails, wayside trafiic-governing means at the entrance end of the section controlled by energy received from said rails and selectively responsive to the number of normal-polarity pulses which are present in the cycles of that energy, and train-carried traiiic-governing means also controlled by energy received from said rails but selectively responsive to the rate of recurrence of the individual pulses of thatenergy.

14 In combination with a section of railway track, means for supplying the rails of said section with recurring cycles of one or another of a plurality of diiferent code pulse combinations each of which is made up of a predetermined number of normal-polarity energy pulses which recur at a predetermined rate and which are separated by time intervals and followed by a time interval together 'with reversed-polarity energy in similar pulse form, means for selectively determining which of said difierent code pulse combinations is supplied to said rails, and wayside trafllc governing means at the entrance end of the section controlled by said coded energy received from said rails and variably responsive, only to changes in the number of normal-polarity pulses which are present in the cycles of that energy,

15. In combination with a section of railway track, means at the exit end of the section for supplying the rails thereof with recurring cycles of one or another of a plurality of diiferent code pulse combinations each consisting of a plurality of normal-polarity energy pulses which recur at a predetermined rate and which are separated by time intervals and followed by a time interval together with reversed-polarity energy in similar pulse form, means for selectively determining which of said different code pulse combinations is supplied to said rails, and train-carried signalling means governed by said coded energy received from said rails and variably responsive only to changes in the rate of recurrence of the individual pulses of that energy.

16. In combination with a section of railway track, means at the exit end of 'said section for supplying the rails thereof with recurring cycles of one or another of a plurality of different code pulse combinations each consisting of a predeterpulse combinations is supplied to said rails, way- 75 side traffic-governing means at the entrance end of the section controlled by said coded energy received from said rails and arranged to respond to the number of normal-polarity pulses which are present in the said cycles thereof and to be insensitive to the rate of recurrence of the individual pulses of which those cycles consist, and train-carried governing means also controlled by said coded energy received from said rails but arranged to respond to the said rate of individual pulse recurrence and to be insensitive to the polarity of the energy of said individual pulses.

17. In combination with a section of railway track, a circuit through which energy may be supplied to the rails of said section, a source of normal-polarity energy and a source of reversedpolarity energy, a plurality of coding contacts each of which is movable from an inactive position either to a first active position in which it establishes connection with one of said sources or to a second active position in which it establishes connection with the other of said sources, means for selectively including one or another of said coding contacts in said rail supply circuit, and actuating means associated with each of said contacts for selectively moving that contact between its said inactive position and its said two active positions at a distinctive rate and in a cyclic manner whereby the contact produces recurring code patterns of normal-polarity connections in a distinctive number followed by a time interval and similarly separated reversedpolarity connections.

18. In combination, a section of railway track, a circuit through which energy may be supplied to the rails of said section, a source of normalpolarity energy and a source of reversed-polarity energy, a plurality of coding contacts each of which is movable from an inactive position either to a first active position in which it establishes connection with one of said sources or to a second active position in which it establishes connection with the other of said sources, means associated with each of said contacts for selectively moving that contact between its said inactive position and its said two active positions in a cyclic manner whereby the contact produces recurring code patterns of normal-polarity connections in a distinctive number separated by time intervals and followed by a time interval and similarly separated reversed-polarity connections, and a group of relays controlled by advance trafiic conditions and arranged selectively to include one or another of said coding contacts in said rail supply circuit.

19. In combination, a forward and a rear section of railway track, means associated with each of said sections for supplying the rails of that section with recurring cycles of one or another of a plurality of different code pulse combinations each of which consists of spaced pulses of nor mal-polarity energy in a distinctive number followed by reversed-polarity energy in similar pulse form, means for selectively determining which of said different code pulse combinations is supplied to said forward section rails, a plurality of traflicgoverning relays at the location of the said supply means for said rear section having slow-release periods suffi cient to span the time between corresponding energy pulses of successive forward section code cycles, means governed in accordance with how many of said relays are picked up for selecting which of said different code pulse combinations is supplied to the rails of said rear section, and means controlled by said coded energy received from the rails of said forward section for sequentially energizing said trafiic governing relays in response to successive normalpolarity pulses of each cycle of said coded energy and in such manner that the same relay receives the same sequential pulse of each normal-polarity series and is thereby maintained picked up as long as cycle series containing that pulse continue to be received from said forward section rails.

20. In combination with a section of railway track, means for supp-lying the rails of said section with recurring series of one or another of a plurality of different code pulse combinations each of which consists of spaced pulses of normal-polarity energy in distinctive number followed by reversed-polarity energy in similar pulse form, means controlled by advance trafiic conditions for selectively determining which of said difierent code pulse combinations is supplied to said rails, decoding means controlled by said coded energy received from said rails and arranged to register the number of normal-polarity pulses which are present in each pulse series of that energy, and trafiic-governing means controlled by said decoding means and selectively responsive to the number of registrations made thereby.

CHARLES W. FAILOR.

CERTIFICATE OF CORRECTION. Patent No. 2,169,605. August 15, 19 9.

CHARLES W. FAILOR.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 15, sec- 0nd column, line 58 claim 7, after the word "circuit" insert with said energy source over said coding contact; page 1h, first column, line 21 claim 10, for "picked-up" read pick-up; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed andsealed this 19th day of September, A. D. 1959.

Henry Van Arsdale,

( Acting Commissioner of Patents.

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