US2395664A - Railway traffic controlling apparatus - Google Patents

Description

Feb. 26, 194-6. c. D. IHRIG 3 5 v RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Aug. 11, 1943 a Sheets-Sheet 1 INVENTOR '(VzZfiordfl [61 69 fla /w Hi1 ATTORNEY 2,39%,sgs4

Feb' 26, 1946; c. o. lHRiG RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Aug. 11, 1943 5 Sheeis-Sheet 2 Feb. 26 1946. c. D IHRIG 3 9 I RAILWAY TRAFF IC CONTROLLING APPARATUS Filed Aug. 11 1945 3 Sheets-Sheet 3 INVENTOR HIJ' ATTORNEY Patented Feb. 26, 19 46 UNITED STATES PATENT QFFICE RAILWAY TRAFFIC CONTROLLING APPARATUS Clifi'ord D. Ihrig, Edgewood, Pa, assignor to The Union Switch and Signal Company, Swissvale, Pat, a corporation of Pennsylvania ApplicationAugust 11, 1943, Serial No. 498,208

2 Claims.

My invention relates to railway trains controlling apparatus, and particularly to the organ- .ization of subh apparatus into novel and imof line circuits, one individual to each controlled function. Thus, for example, if two functions located respectively at either end of a track sec tion are to be governed from the opposite ends of that section, it is customary to extend two line circuits, one for each function, between the ends of the section.

It is an object of my present invention to pro vide novel and improved means whereby a single line circuit is rendered capable of independently and concurrently controlling two functions, one at either end of the circuit.

Another object is to provide novel and im- I proved means for segregating two functions controlled by circuits which include two line wires in common.

An additional object is to provide novel and improved means controlled by a coded track circuit for independently and concurrently governing a plurality of functions over a single pair of line wires.

A further object is to provide novel and improved means controlled by a coded track circuit for reducing the number of line wires required to govern a plurality of functions associated with the track circuit.

Another object is to provide novel and improved railway trailic controlling systems of the class employin line circuits in conjunction with coded track circuits.

The above-mentioned and other important objects and characteristic features of my invention which will become readily apparent from the following description, are attained in accordance with the invention by providing at the two ends of a line circuit, coding contacts operated in synchronism by means of coded energy transmitted through the track rails and operative to provide alternately two circuits each including in commen the wires of the line circuit.

I shall describe two forms of apparatus embcdying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is 9.- diagrammatic view illustrating one form of apparatus embodying my invention, and Figs. 2a and 22), when placed end to end with Fig, 2a on the left, comprise a diagrammatic View illustrating a modification of the apparatus shown in Fig, 1 and also embodying my invention. In each of the two views, similar reference characters have been employed to designate corresponding parts.

Referring first to Fig. 1, the reference characters I and l a designate the track rails of a stretch of railway track divided by insulated joints 2 into a track section IT. Section IT is provided with a track circuit of the coded current class including code generating apparatus located at one end of the section and code responsive means located at the opposite section end. The code generating means comprises, as shown, a code transmitter or coder CT energized from a suitable source of current, such as a battery, not shown, but having its opposite terminals designated by the reference characters B and C. The coder CT is provided with a plurality of contacts 15a, 15b and 150 which are periodically operated, for example at a rate of times per minute, into and out of engagement with associated front contact points so as periodically to make and break circuit controlling contacts at the rate of 75 times per minute. A suitable source of current, such as a track battery 3, is connected with and disconnected from the rails l and la adjacent to v the left-hand end, as viewed in the drawings, of section IT according as contacts 151) and of coder CT are operated into or out of engage ment with their associated contact points respectively, whereby the rails of section iT are supplied with coded current comprising alternate on and off intervals during which current is and is not supplied to the rails, and which intervals recur at the rate of '75 times each minute. Associated with coder CT is a repeater relay CTP energized over an obvious circuit including contact 15a of coder CT and a battery 4. The func tion of relay CTP will be pointed out in the following description.

The code responsive apparatus comprises, as shown, a track relay TR connected across the rails at the opposite or right-hand end of the section, and this relay has a plurality of contacts 6, 1, 8 and 9 which are operated into engagement with associated front or back contact points according as relay TB is energized or deenergized respectively. When section IT is unoccupied, relay TR will operate its contacts to their front points in step with the on intervals of the coded current supplied to rails I and la, and will operate these contacts to their back points in step with the off intervals of such coded current. Relay TR has associated therewith a detector relay TPR which is energized by current supplied through a decoding transformer DT when and only when the track relay follows coded energy, as explained in Letters Patent of the United States No. 2,237,788 to Frank H. Nicholson et al.

Section IT has associated therewith a line circuit comprising two line wires I4 and I5 which extend between the opposite ends of the section and which may be utilized for controlling from controlled function and located at the opposite end of the section; and switching means for alternately connecting first one and then the other of the two sets of controlling apparatus to the line wires, and for, alternately connecting first one and then the other of the two energy tran mitting means to the line wires. The switching means is synchronized so as to connect the controlling apparatus associated with one function to the line wires at the same time that the energy transmitting means associated with that function is connected with the linewires, and to connect the controlling apparatus associated with the other function to the line wires at the same time that the energy transmitting means associated with such other function is connected with the line wires.

As shown in Fig. l, the controlling apparatus comprises two relays HDRI and HDRZ, preferably of the retained neutral polarized type, located at opposite ends of the section for controlling two functions (not shown but preferably located also at the opposite section ends). These relays are preferably provided with slow releasing characteristics, effected in part at least by means of resistors Il connected across their respective windings. The polarized relays HDRI and HDR2 are shown as single instruments, but it is contemplated that a polar relay and a neutral or polar biased neutral relay energized in series as shown in Letters Patent of the United States No. 2,324,200 of Arthur E. Dodd may be employed if desired.

The energy transmitting means comprise suitable sources of current, such as batteries I8 and I9, together with pole changing means which are shown in the form of relays PCRl and PCRZ. The relays PCRI and PCB! may be controlled in any suitable manner (not shown) either manua ly or automatically by traffic in the stretch.

The switching means comprise contacts of repeater relay CTP and contacts of track relay TR, which contacts are operated in synchronism by means of coder CT. When coder CT operates its contacts to their front positions, contacts 1 and 8 of relay TR are caused to operate to their front positions in response to the energy transmitted from battery 3 over the track rails to relayTR, and contacts 20 and BI of relay CTP are likewise caused to operate to their front positions in response to the energization of relay CTP. Similarly, when coder CT operates its contacts out of engagement with their associated front points, contacts I and 8 of relay TR operate to their back positions since relay TR will now be deenergized because no current is available in rails l and Ia during the off periods of the code, and relay CTP likewise operates itscontacts 28 and El to their back positions because the energizing circuit for that relay is interrupted.

The line circuit is arranged as shown in Fig. 1 so that when the switching contacts of relays CTP and TR are in their front positions, relay I-IDRI is connected with battery I 9 over a circuit which extends from one terminal of battery l9 through front contact 22 of pole changing relay PCR2, front contact 23 of relay TPR, front contact 8 of relay TR, line wire Id, front contact 29 of relay CTP, winding of relay HDRI, front contact ZI of relay CTP, line wire it, front contact 9 of relay TR, front contact 25 of relay TPR, and front contact 25 of relay .PCRZ to the other terminal of battery I9. In this condition of the apparatus, current of one polarity, which may be considered normal polarity, is supplied over line wires I l and I5 to relay HDRI to energize that relay and cause it to operate its polar armature to its normal or left-hand position as shownin the drawings. If, however, relay PCRZ is released so that contacts 22 and 25 engage their respective back points, the polarity of current supplied. to relay HDRI will then be reversed, as is obvious from an inspection of the drawings, and that relay polar armature will be operated to its reverse or right-hand position. 7

When the switching contacts of relays CTP and TR are in their back positions, relay HDRZ is connected with battery I8 over a circuit which extends from one terminal of battery I3 through front contact 26 of relay PCRI, back contact 28 of relay CTP, line wire I4, back contact 8 of relay TR, front contact 21 of relay TPR, winding of relay I-IDRZ, front contact 28 of relay 'ITR, back contact 9 of relay TR, line wire I5, back contact 2| of relay CTP, and front contact 29 of relay PCRI to the other terminal of battery I8. When the circuit just traced is completed, relay HDR2 is supplied with current of normal relative polarity from battery I8 and operates its polar armature to its left-hand or normal position, but if relay PCRI isreleased, the polarity of current supplied to relay HDR2 will then be reversed and that relay will operate its polar armature to its right-hand or reverse position.

The two circuits just traced are alternately completed as long as section IT is vacant. The polarized relays HDRI and HDR2 accordingly will be energized alternately, and by reason of their slow releasing characteristics, the neutral armature of each of these relays will be held up during the intervals that the other relay is energized, so that the neutral contacts of each relay are held in their picked-up position due to the periodic energization of that rela over the line circuit. Because of the synchronized operation of the switching contacts of relays CTP and TR, the two circuits are segregated and the proper relay will at all times be connected in circuit with the proper source and an improper connection of one relay with the source of the other relay cannot be obtained. The neutral and polar contacts of the control relays I-IDRI and HDRZ may cooperate to control circuits which may be employed in any suitable manner for any appropriate purpose.

To assist in the synchronization of the switching contacts at the two ends of the circuit, the repeater relay CTP is employed and is adjusted to introduce substantially the same delay in the operation of its contacts as is introduced into the operation of the contacts of relay TR due to the characteristics of the track circuit. In other words, if there is any phase lag or code distortion introduced into the operation of relay TR by virtue of the impedance of the track circuit or for any other reason, such phase lag or code distortion will be compensated for b adjusting relay CTP to operate its contacts to produce a corresponding phase lag or code distortion pattern.

When a train moving in either direction enters section I T' rela TR is shunted, and relay TPR will release to open its contacts interposed in each branch of the line circuit and will thereby disconnect both battery l9 and relay HDR2 from the line circuit until the section is vacated. This insures that both control relays HDRI and HDR2 will be controlled by traific on the associated section.

The apparatus shown in Fig. 1 is arranged so that two different functions may be controlled concurrently over one line circuit. In the system shown in Fig. 1, as long as relay TPR is picked up, energy is supplied over the line wires from the battery 19 at the right-hand end of the line circuit to the rela HDRI at the left-hand end of the line circuit when the contacts of relays CTP and TR, are both picked up, and is supplied from the battery l8 at the left-hand end of the line circuit to the relay HDRZ at the right-hand end of the line circuit when the contacts of relays CTP and TR are both released.

However, the invention is not restricted to the supply of energy in opposite directions over the line wires in the two positions of the contacts of the relays CTP and TR, and it is contemplated that both control relays may be located at one end of the line circuit and both sources of current be located at the other end of the line circuit and that when the contacts of relays CTP and TR are both picked up energy from one source is supplied over the line wires to one control relay, and when the contacts of relays CTP and TR are both released energy from the other source is supplied over the line wires to the other control relay.

In Figs. 2a and 2b the apparatus of Fig. 1 is shown incorporated into an absolute permissive block (A. P. B.) system for controlling trafiic in either direction over a stretch of. track extending between two passing sidings WS and ES. Referring now to Figs. 2a and 2b, the rails l and i a are divided by insulated joints 2 into a plurality of successive track sections 2T, 3T, etc., each of which is provided with a coded track circuit similar to that explained in detail in connection with the apparatus of Fig. 1. In Figs. 2a and 2?), however, each coder CT functions to code the track circuit current supplied to the adjacent ends of two adjoining track circuits, that is, coder 2-3CT codes the current supplied to the right-hand end of section 2'1 and to the left-hand end of section 3T; while coder 4-5CT codes the current supplied to the right-hand end of section AT and to the left-hand end of section 5T.

Each track circuit includes a code following track relay TR operated by coded energy supplied over the section rails, while each track relay has associated therewith a code detecting relay TPR 'to which energy is supplied through a decoding transformer DT when and only when the track relay is following code.

Signals 2S and 4S are provided for governing eastbound traflic moving over the stretch from left to right as viewed in the drawings, while signals 38 and 58 are provided for governing westbound traffic operating from right to left over the stretch. These signals may be of any suit able type, such as semaphore, searchlight, etc., but for the purposes of the present description it will be assumed that the signals are of the color light type each having a green lamp G, a yellow lamp Y and a red lamp R efiective when lighted to display a proceed, a caution or a stop indication, respectively.

Each signal S has associated therewith a polarized control relay, designated by the reference character HDR with a numerical prefix corresponding to the prefix employed in the reference character of the associated signal. Each relay HDR. is provided with slow releasing characteristics effected in part at least by means of a resistor i! connected across its terminal, and each relay I-IDR is provided with a slow releasing repeater relay, designated by the reference character HPR with a numerical prefix corresponding to the prefix of the associated polarized relay,

energized over an obvious circuit when the neutral armature of theassociated polarized relay HDR is picked up to close its front contact 35. Each polarized relay HDR and associated repeater relay I-IPR cooperates to control the associated signal S in such a manner that when the neutral armature of a polarized relay HDR is picked up, the associated signal is caused to dis play either its proceed or its caution indication according as the polar armature of the polarized relay is in one or the other of its two positions, and when a repeater relay HPR is released due to the release of the neutral armature of its associated polarized relay HDR, the associated signal is caused to di -play stop. For example, when neutral contact 35 of relay ZHDR is picked up to cause relay ZHPR. to pick up and close its front contact 36, the associated signal 28 is caused to display its proceed or its caution aspect according as lamp G or lamp Y of that signal is energized over an obvious circuit extending from terminal B through front contact 36 of relay 2HPR, normal polar contact 3i33 of relay ZHDR and the filament of clear or proceed lamp G of signal 25, or reverse polar contacts 3139 of relay ZHDR and the filament of lamp Y of signal 28 to terminal C, respectively. When neutral contact 35 of relay ZHDR is released, its repeatcr relay ZHPR also is released and lamp R of signal 28 is then energized over an obvious circuit including back contact 36 of relay ZHPR.

Relays ZHDR and 3HDR are controlled in accordance with my invention by means of a single line circuit involving two line wires 14 and I5 which extend between the remote ends of the two adjoining sections 2'1 and 3T; and relays AHDR and 5HDR are likewise controlled in accordance with my invention by means of a similar line circuit extending between the remote ends of sections 4'1 and ET. Also involved in the control of these relays are directional stick relays 3S3 and 48R provided for signals 3S and as, respectively, and by means of which there is attained the usual directional control of signals customary in A. P. B. systems. Stick relay 38R is provided with a pick-up circuit which extends from terminal B through back contact 5?} of relay STPR, front contact d5 of relay SHPR, and the winding of relay ESE to terminal Cj and with a stick circuit wherein front contact 42 of relay 38R is concontrolling such contact.

the just traced circuit. In addition, the stick circuit of relay GSR is provided with an alternate path which extends from terminal B through back contact 4! of relay BHPR and front contact 42 ofrelay 3S3 to the winding of the relay. Relay 48B is provided with similar pick-up and stick circuits, as is readily apparent from an inspection of the drawings.

To assist in the tracing of circuits hereinafter to be described in detail, contacts of relays have .at times been shown in the drawings separated from the Winding of the relay operating such contacts, but in each of such cases these contacts have been identified by a reference character individual to such contact and by placing above such contact the reference character of the relay For example, the reference character 33R is placed above contact 55 to indicate that this contact is associated with and operated by relay .iSR.

The supply of energy to the left-hand end of the line wires hi and i is governed in part by relays IHDR and IHPR which are controlled by traffic conditions in the track stretch beside passing siding WS in such manner that polar relay IHDR is deenergized when the portion of this part of the track stretch adjacent the right-hand or east end of the passing siding is occupied, while if this portion of the track stretch is vacant energy of normal or reverse polarity is supplied to the relay IHDR. according as the portion of the track stretch adjacent the west end of the passing siding WS is vacant or is occupied. The slow releasing neutral relay il-IPR is controlled by neutral contact 35 of relay IHDR as is obvious from the drawings.

Similarly, the supply of energy to the east or right-hand end of the line wires associated with sections ST and ET is governed in part by relays SHDR. and BI-IPR which are controlled by traflic conditions in the track stretch beside the passing siding ES.

The equipment is shown in the condition which it assumes when the track stretch is vacant. At this time relay llI-IDR is energized by current of normal polarity supplied over the line wires associated with sections 4T and 5T, and energy is supplied over front contact 35 of relay 4HDR. to relay 4HPR and its contacts are picked up so that energy of normal polarity is supplied to the east end of line wires l4 and IS. The supply of energy to relay 4I-lIDR is controlled in a manner similar to that about to be described for relay 3HDR.

In addition, at this time relay IHDR is supplied with energy of normal polarity by means not shown so relay lI-IPR is picked up.

As sections 2T and 3T are vacant the track relays ZTR and 3TB are operated in synchronism by energy supplied over the track rails as a result of operation of code transmitter 2-3CT. As a result of code following operation of the track relay-s 2TB and 3TB, energy is supplied through the decoding transformers 2DT and 3DT to the relays ZTPR and 3TPR, respectively, to permit energy to be supplied to the line wires l4 and l 5, and to permit the control relays to be connected to the line wires.

When the contacts of track relays 2TB and 3I'R are both picked up as shown, energy may be supplied over the line wires l4 and 15 from a source at the right-hand end of the line circuit to the control relay ZHDR atthe left-hand end of the line circuit, and as relay GHPR is picked up nected around front contact 4| of relay -3HPR in this energy is of normal polarity. The circuit for supplying energy to relay 2HDR is traced from terminal B of a source of current, not shown, over front contact 44 of relay AHPR, back contact 45 of relay 38R, front contact 46 of relay STPR, front contact 4'! of track relay 3TB, line wire hi, front contact 48 of track relay ZTR, front contact 49 of relay 2TPR, winding of relay 2HDR, front contact 50 of relay ZTPR, front contact iii of relay 2TB, line wire 15, front contact 52 of relay 3TB, front contact 53 of relay 3TPR, and front contact 54 of relay 4HPR to terminal C of the source.

The energy supply to relay ZHDR, picks up the relay neutral contact 35 so that energy is supplied to relay 2HPR, while the polar contact 38 of relay ZHDR occupies its left-hand or normal position so that energy is supplied to the green or clear lamp G of signal 2S over the circuit which includes front contact 36 of relay ZHPR.

On release of the contacts of the track relays V 2TB and 3TB the supply of energy to relay 2HDR is cut off, while energy of normal polarity is supplied to relay liHDR over the circuit which is traced from terminal B over wire 61, normal polar contact 66 of relay IHDR, front contact 65 of relay IHPR, front contact 64 of relay Z'I'PR, back contact 51 of relay ZTR, line wire 15, back contact 52 of track relay 3TB, front contact 63 of relay 3TPR, winding of relay 3HDR, back contact 62 of relay 48R, front contact 6| of relay 3TPR, back contact 41 of relay 3TB, line wire 14, back contact 48 of relay 2TB, front contact 6B of relay ZTPR, front contact 59 of relay lI-IPR', normal polar contact 58 of relay IHDR, and wire 51 to terminal C.

The energy supplied to relay 3HDR causes the neutral contact 35 of this relay to be picked up so energy is supplied to relay 3HIPR, while the polar contact 37 of relay SHDR occupies its left-hand or normal position so that energy is supplied to the green or clear lamp G of signal 38 over the circuit which includes front contact 36 of relay 3HPR.

At this time, therefore, the signal 28 governing entrance of eastbound signals in the single track stretch, and the westbound intermediate signal 38 both display clear indications.

In like manner, as relay BHDR is energized by current of normal polarity, and as relay BHPR is picked up, energy of normal polarity is supplied over the line wires associated with track sections AT and ST to relay AHDR during the picked-up periods of track relays 4TB and 5TB. Similarly, as relay SHPR is picked up energy of .normal polarity is supplied over these line wires to relay SHDR during the released periods of the track relays l'IR and 5TH, while as relays 4HDR, and EHDR are both energized with current of normal polarity the signals is and 58 are caused to display their green or clear indications.

At this time relay 35R is released as relays 3TPR and 3I-IPR. are picked up, while relay 45B.

is released as relays fl-IPR; and ATPR are picked If an eastbound train now enters the portion of the track stretch at the left of section 2T, the energy supplied to relay II-IDR is changed from normal to reverse polarity by means not shown and the polar contacts 58 and 65 of relay iHDR move to their right-hand or reverse positions, thereby cutting oi the supply of energy of normal polarity and causing energy of reverse polarity to be supplied over line wires 14 and 45 to relay 3HDR during the released periods of the contacts of track relays 2TB. and 3TB. On this change in the polarity of the energy suplied to relay 3HDR, the polar contact 31 of the relay is moved to its right-hand or reverse position, thereby interrupting the circuit of the green lamp G and establishing the circuit of the yellow or caution lamp Y of this signal. At this time relay SHPR. remains picked up and its contacts 70 and 'H maintain the supply of energy of normal polarity to relay 5HDR so that it maintains the display of the green or clear indication by signal 58.

When the eastbound train advances somewhat nearer to the track section 2T the supply of energy to relay IHDR is cut off and its neutral contact 35 releases to interrupt the circuit of relay lI-IPR and contacts 59 and 65 of relay IHPR release and establish a circuit independent of relay IHDR for supplying energy of reverse polarity to relay EHDR so that signal 35 continues to display its yellow or caution indication.

When the eastbound train enters section 2T track relay 2TB. remains released and its contacts 48 and 5| do not establish the circuit of relay ZI-IDR. so its neutral contact 35 interrupts the circuit of relay ZHPR and its contact 36 releases to interrupt the circuit of the green lamp G and establish the circuit of the red lamp R of signal 28.

When the eastbound train advances into section 2T the track relay ZTR ceases to follow code and energy is no longer supplied through the decoding transformer EDT to relay 2'IPR. and relay ZTPR, releases so that its contacts 19 and 53 additionally interrupt the circuit of relay Zl-IDR and contacts 60 and 64 of relay ZTPR cut off the supply of energy to the line wires I l and I5 over back contacts 58 and 5| of track relay 2TB so relay SHDR releases and its contact 35 interrupts the circuit of relay 3HPR and contact 36 of relay SHPR interrupts the circuit of the yellow lamp Y and establishes the circuit of the red lamp R of signal 3S.

On release of relay SHPR its contact ll interrupts th pick-up circuit of relay 38R so that relay SSR will remain released on subsequent release of relay S'IPR.

In addition, on release of relay 3HPR its contacts i and H interrupt the supply of energy of normal polarity to relay I-IDR over the line wires associated with sections 4'1 and ST, while on movement of contacts 70 and H into engagement with their back contacts no energy is supplied to these line wires since contact an of relay 38B is released. Accordingly, relay 5HDR releases and causes release of relay EHPR so that signal 58 displays its red or stop indication to prevent a westbound train from advancing beyond the passing siding ES and entering the single track stretch.

The supply of energy to relay ll-IDR over the line wires associated with section AT and ST is not disturbed at this time and signal 48, therefore, continuesto display its green or clear indication.

When the train advance into section 3T the track relay 3TB ceases to follow code and energy is no longer supplied through the decoding transformer 3DT to relay 3TPR and the contacts of relay 3TPR release to prevent supply of energy to line wires l4 and I5 at the east end thereof and to prevent supply of energy from the line wires to relay SHDR.

When the train advances into section GT the track relay 4TB ceases to follow code and remains released so that its contacts interrupt the circuit for supplying energy from the line circuit to relay QHDR and the neutral contact 35 of relay AHDR releases and interrupts the circuit of relay GHPR so that its contact 35 releases to interrupt the circuit of the green lamp G and to establish the circuit of the red lamp R of signal 43. V

In addition, when track relay 4TB ceases to follow code energy ceases to be supplied through the transformer lDT to relay @TPR and relay QTPR releases to prevent supply of energy from the line circuit to relay iHDR and to prevent supply of energy to the west end of the line circuit. The relay lTPR is somewhat slow in releasing so that its contacts will remain picked up during the intervals between impulses of energy supplied to the relay from the decoding transformer. Likewise, the relay iHDR is of a type the neutral contacts of which are slow to release so that these contacts will remain picked up in the periods during which the supply of energy from the line circuit to the relay is cut off, while the relay ZHPR, which is controlled by the neutral contact 35 oi relay GHDR, is of a type the contacts of which are slow in releasing. The various part of the sys tem are arranged and proportioned so that when a train enters section 41 and the track relay 4TB. ceases to follow code, thereby cutting off the supply of energy to relays l'rPR and ch03, the contacts of relay iHPH, will remain picked up until after the contacts of relay 4TPR release. Accordingly, on release of relay iTPR, energy is supplied over back contact 12 of relay lTPR. and

front contact E3 of relay ii-1P3. to relay 46R and its contacts pick up so that its front contact 14 establishes a stick circuit to maintain the relay picked up as long as either relay iTPR or 4HPR is released.

In addition, when relay 45R picks up, its contact 62 interrupts the circuit of relay 3HDR to thereby insure that this relay remains released and maintains the display of a stop indication by westbound signal 38. Also on picking up of relay 45R its front contact 55 is closed to permit energy to b supplied to the line wires l4 and IE on code following operation of track relay 3TR and picking up of relay 3TPR, while at this time contact SI of relay tSR is picked up to prevent supply of energy to the west end of the line circuit associated with sections QT and ST and thereby insure that relay 5HDR will remain released and maintain the display of the stop indication by signa1 5S.

When the train advances into section 5T the track relay 5TB ceases to follow code and relay STPR. releases to prevent supply of energy to the line circuit associated with sections 41 and ET and to prevent the supply of energy from this line circuit to relay EHDR. I

When the train advances into the portion of the track stretch beside the passing siding ES relay SHDR is deenergized by means not shown and its neutral contact releases to interrupt the circuit of relay GHPR so that its contacts release and establish the circuit to permit energy of reverse polarity to be supplied to the line circuit for sections 41' and ET on picking up of the contacts of relay STPR.

When the train vacates the portion of the track stretch beside passing siding WS energy of normal polarity is supplied to relay lI-IDR by means not shown and its polar contacts move to their left-hand or normal positions While the relay neutral contact 35 picks up and establishes the circuit of the relay IHPR so that its contacts 59 and 65 pick up to establish the circuit to permit energy of normal polarity to be supplied to the line wires and When the train vacates track section 2T the track relay 2TB, again responds to codedenergy supplied over the section rails and relay ZTPR- picks up to permit energy to be supplied to the west end of line wires 14. and I 5 and topermit energy to be supplied from the line wires to relay 2HDR.. As long as section 3T is occupied relay 3TPR is released and prevents supply of energy to the line wires l4 and i5 and prevents supply of ener y from these line wires to relay SHDR.

When the train vacates. section 3T the track relay 3TB responds to codedjenergy supplied over the section rails and relay 3TPR picks up so that its front contacts 61 and B2 are closed but at this time contact 62-; of relay 43R. is picked up and preventssupp'ly of. energy to relay 3HDR so it remainsreleased and maintains the display of the. stop indication bysignal 38. In addition, when relay 3TPR picks up its contacts 46 and 53 establish the circuit including front contact 55 of relay 4SR, back' contacts 45, and 540i. relay 4HPR, and back contact 45. of relay 35R, for supplying energy of reverse polarity to line wires 14 and. I5, during the picked-up periods of track relay 3TB. This energy. feeds over line wires 14 and IE to relay ZHDR. and causes its polar con-. tact 31 to occupy its right-hand or reverse position, while the neutral contact 35, of the relay ispickedupto establish the. circuit oi: the relay ZHPR andits neutral contact 36 is picked up, to interrupt the circuit of the red lamp R of signal 28 and to establish the circuit including polar contacts 31-39 of relay ZHDR- for supplying energy to the yellow or caution lamp Y of signal 28 so thatthis signal now displays a permissive indication to authorize a second or following casts bound train to enter the single track stretch.

When the train vacates section 41 the track relay 4TB responds to coded energy supplied over the section rails and relay 4TPR picks up so that its contacts establish. the connections over which the relay 4HDR is.- connected to the line circuit during the picked-up. periods of the contacts of the track relay 4TB. At this time relay 5TPR,

is released, and track relay 5TB. is also released so that energy is not supplied to the east end of this line circuit and relay 4HDR, therefore, re-. mains deenergized even though it is connected with the line circuit, Accordingly, contact 35 of relay 4HDR. remains released and interrupts the circuit of relay 4HPR so that contact 36 of relay 4l-IPR maintains the circuit of the red lamp R of signal 4S, while contactflt of relay 4HER maintains a stick circuit for relay 48R sothat contact 55 of relay 48R maintains the circuit orfiup lyins e e y. o re er o a i to n wires 14 and I5, contact 62 of relay 4SRprevents supply of energy to relay 3l-IDR, and contact Bl of relay 48R prevents supply of energy to the west end of the line circuit associated with sections 4Tand 5T. v we When the train vacates section ET the track relay 5TB responds to coded energy supplied over the rails of section 5'1 and energy is supplied through the transformer EDT to" relay 5TPR and its contacts pick up to permit energy to be supplied to the east end of the line circuit for sections 4T and ti and to permit energ supplied to this line circuit atthe west end thereof to be supplied to relay SHDR. After 5TPR picks up energy of reverse polarity is su plied to the line circuit for sections 4T and ST over back contacts facts of track relay 4TB. and of relay 4TPR- to relay 4I-IDR and causes its polar contact 3-! to move to its-right hand or reverse position, while neutral contact 35 of the relay is picked up and establishes the circuit of relay 4HPR so that'- its contacts pick; up and contact 36 interrupts the circuit of the red lamp R of signal 48 and establishes the circuit including reverse polar contact 3! of relay 4HDR for supplying energy to the yellow or caution lamp Y of signal 4S.

In addition, when relay 4HPR picks up its contact 13- interrupts the stick circuit for relay 48R;- and the contacts of relay 43R release so that contact 82 establishes the circuit of relay 3'HDR, while on picking up of relay 4HPR its contacts 44 and 54 interrupt the circuit controlled by contact 55 of relay 48R for supplying energy of reverse polarity to line wires l4 and i5 and establish a circuit to supply energy of normal polarity to these line wires. On this change in the polarity of the energy supplied to the east end of line wires l4 and I5 the polar contact 31 of relay ZHDR, is'moved from its right-hand or reverse position to its left-hand or normal position to interrupt the circuit of the yellow lamp Y and establish the circuit of the green lamp G of signal 28.

On release of relay 38R and establishment by its contact 62 of the circuit of the relay 3HDR energy'supplied to the line wires [4 and if: at the west end thereof feeds to relay 3HDR and picks up its neutral contact 35 to establish the.

circuit of relay SHPR. and cause its contact 36 to pick up and interrupt the circuit of the red lamp R. of signal 38 and establish a circuit including polar contact 31 of relay 3HDR for supplying energy to one of the other lamps of this signal.

On release of relay 48R its contact 8! establishes the circuit for supplying energy to the west end of the line circuit associated with sections 4T and 5T, while on picking up of relay SHPR its contacts 10 and ll cause energy of normal polarity to be supplied to this line circuit. This energy feeds to relay EHDR and picks up its neutral contact to establish the circuit of relay SHPR. while relays 5I-IPR. and 5HDR cooperate to cause signal 58 to display its green or clear indication to authorize a westbound train to enter the single track stretch.

When the eastbound train advances far enough for energy of normal polarity to be supplied by means not shown to relay BHDR, the polarity of the energy supplied to the east end of the line circuit for sections 4T and 5T is changed from reverse to normal, and on this change the polar contact 31 of relay 4HDR is moved from its reverse to its normal position to cause signal 48. to display its green instead of its yellow indication. At this time relay 4HPR. remains picked up and maintains the supply of energy of normal polarity to the east end of line wires l4 and IE to maintain the display of the green or clear indication by signal 28, and the equipment is again in the condition which it assumes when the track stretch is vacant.

The equipment operates in substantially the same manner on movement of a westbound train through the track stretch and a detailed description of the operation of the equipment at such times is unnecessary.

Although I have herein shown and described only two for-ms of railway traffic controlling ap paratus embodying my invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a railway signaling system, in combination, a stretch of railway track including adjacent first and second track sections, a coding device controlling the supply of energy to the rails of the first section at the end thereof adjacent said second section and also controlling the supply of energy to the rails of said second section at the end thereof adjacent said first section, a first code following track relay at the end of the first track section remote from the second track section and operated by energy supplied over the rails of said first track section, a second code following track relay at the end of the second track section remote from the first track section and operated by energy supplied over the rails of said second track section, the apparatus being arranged so that when both track sections are vacant the contacts of said track relays are operated between their first and second positions substantially in synchronism, a first detector relay associated with said first track relay, a second detector relay associated with said second track relay, means effective when and only when said first track relay is responding to coded energy to supply energy to said first detector relay, means efiective when and only when said second track relay is responding to coded energy to supply energy to said second detector relay, a pair of line wires paralleling said first and second track sections, a first and a second control relay, means including front contacts of said first and second detector relays for supplying energy over said line wires to said first control relay when the contacts of both of said track relays are in a selected one of their two positions, and means including front contacts of said first and second detector relays for supplying energy over said line wires to said second control relay when the contacts of both of said track relays are in the other one of their two positions.

2. In a railway signaling system, in combination, a stretch of railway track including adjacent first and second track sections, a coding device controlling the supply of energy to the rails of the first section at the end thereof adjacent said second section and also controlling the supply of energy to the rails of said second section at the end thereof adjacent said first section, a first code following track relay at the end of the first track section remote from the second track section and operated by energy supplied over the rails of said first track section, a second code following track relay at the end of the second track section remote from the first track section and operated by energy supplied over the rails of said second track section, the apparatus being arranged so that when both track sections are vacant the contacts of said track relays are operated between their first and second positions substantially in synchronism, a first detector relay associated with said first track relay, a second detector relay associated with said second track relay, means effective When and only when said first track relay is responding to coded energy to supply energy to said first detector relay, means effective when and only when said second track relay is responding to coded energy to supply energy to said second detector relay, a pair of line wires paralleling said first and second track sections, a first and a second polarized control device, means including front contacts of said first and second detector relays for supplying to said first polarized control device over said line wires when the contacts of both of said track relays are in a selected one of their two positions energy which at times is of one polarity and at other times is of the other polarity, and means including front contacts of said first and second detector relays for supplying to said second polarized control device over said line wires when the contacts of both of said track relays are in the other one of their two positions energy which at times is of one polarity and at other times is of the other polarity.

CLIFFORD D. IHRIG.

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