US1984840A

US1984840A - Railway signal system

Info

Publication number: US1984840A
Application number: US581546A
Authority: US
Inventors: James A Parkinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-12-17
Filing date: 1931-12-17
Publication date: 1934-12-18
Anticipated expiration: 1951-12-18

Description

Dec. 18, 1934. J, A. PARKINSON RAILWAY SIGNAL SYSTEM Filed Dec. 17, 1951 3 Sheets-Sheet 1 III]: INVENTOR. James A Par/ 156125012.

111.5 ATTORNEY.

5 Sheets-Sheet 2 J. A. PARKINSON RAILWAY SIGNAL SYSTEM Filed Dec. 17, 1931 Dec. 18, 1934.

R93 WNAQRND 11v VENTOR. James A Parliinsmz 5 His ATTORNEY.

1360- 3 J A. PARKINSON RAILWAY SIGNAL SYSTEM Filed Dec. 1'7, 1931 3 Sheets-Sheet 3 IN VENTOR. James/J. Parkinson HIS ATTORNEY.

Patented Dec. 18, 1934 PATENT o ncE James A. Parkinson, Topeka, Kans.

Application'December 17, 1931, Serial No. 581,546.

14 Claims. (Cl.'24633) My invention relates to railway'sign'al systems,

and particularly to railway signal systemsgoverning traific in both directions over a stretch of.

railway track.

I will describe one form of system embodying my invention, and will then point out the novel features thereof in claims. 1

Figs. 1, 2 and 3, when placed end to .end in the order named, constitute a diagrammatic view of one form of system embodying my invention when applied to a stretch of railway extending between two passing sidings designated by the reference characters P1 and P2.

In describing my invention, reference is made to the accompanying drawings wherein like characters of reference designate corresponding parts with a prefix or sufiix added to the reference character in many instances to designate the location. In certain instances a circuit controlling contact is located on the drawings at a point remote from the relay controlling the contact inorder to simplify the disclosure as much as possible inorder that it may be more readily understood. In each instance, such circuit con-, trolling contact is given a reference characterhaving a prefix corresponding to the reference character for the relay controlling the contact, and the position in which the contact is shown corresponds to the normal condition of the relay.

For example, the circuit controllingfront con tact designated by the reference character B1TR of Fig. 1 is operated by the track relay BlTR and the contact is shown closed inasmuch as the relay BITE is normally energized. I shall assume the right-hand end of each view to be east and the left-hand end to be west, and I shall speak oftraffic moving from the right to the left as westbound trafiic and that moving from the left to the right as eastbound traflic.

- The traffic rails 1 and 2 are divided into track blocks AB, B-C, CD and D-E by the usual insulated rail joints in the customary manner. Each track block is divided into two track sections as will be understood by an inspection of Figs. 1, 2 and 3. In the trackblock CD-there trafiic rails 1 and 2 at one end of the section, and a track relay TR with a prefix corresponding to the location connected to the rails at the opposite end of the section. In connection with the track section at the east end of the passing sid- 5:

ing P1, the track reI'ayA2 TR is provided with a pick-up circuit that includes a back contact GR of a trafilc direction controlling relay GR to be later referred to, and also with a stick circuit that includes its own front contact 92 as will be 10;

readily understood by an inspection of Fig. 1. It follows that once the track section at the switch 1S of siding P1 is occupied and track relay AZTR shunted, the relay can be reenergized only when the trafiic direction controlling relay GR is deenergized to close the back contactGR The function of this feature in the controlling of the. track relay AZTR will appear later in the specification. I

The switch controlled relay 1SKR associated with the switch 1S for thepassing siding P1 is energized through contacts of a switch circuit controller operated by the movement of the switch IS in the manner well understood in the art. That is to say, with switch 1S set for main line trafiic, the relay 1SKR. is energized by current of one polarity and when switch is is set for .trafiic' to the siding P1, the relay 1SK R is energized with current of a reverse polarity. In a likemanner, the energizing of the switch controlled relay ZSKR is governed by the movement of the switch for the siding P2. j

At each location A, B, C, D, and E there is located an eastbound signal designated by the reference character R plus a SllfilX corresponding to the location, and a west-bound signal L with a sufiix' corresponding to the location. These signals may be of any standard type and are here shown as three-position searchlight signals. As the mechanisms of the signals form no part of my invention, it is deemed suflicient for thisdescription to point out only the general operation of the signal mechanism. Referring to the signal RB, for example, a spectacle arm designated by the dotted lines 88 is provided at its upper end with three different colored filters 12, 13 and 14 and is operated by the armature 15. The armature 15 is normally biased by means not shown to a position where the filter 13, which is colored red, is brought in alignment with a light 4 and the signal 0 RB displays a stop indication. The field winding. 16 is permanently connected to a local source of direct current not shown but indicated on the drawings by the reference character X for the positive terminal and by the reference character Y for the negative terminal. With field winding 17 energized with direct current of one polarity in a manner to be later pointed out, the armature 15 is rotated in a clockwise direction until filter 14, which is colored yellow, is brought in alignment with the light 4 and signal RB displays a caution indication. With field winding 17 energized with current of a reverse polarity, the armature 15 is rotated in a counterclockwise direction'untilfilter. 12, which is colored green, isaligned with light 4 and signal RB-displays a clear indication. The armature 15 also actuates two circuit controllers l8 and 19 attachedto the armature 15 as indicated by: dotted lines. Each of the wayside signals of my system operate in the same manner as that just described for signal RB.

While the light 4 may be illuminated in different ways, a preferred form of lightingcircuits is that where the light is normally supplied with current froman alternating current transmission line, and a local standby source of direct current isto be automatically cut into service in the case ofa loss of-alternating current power. Thelight 4' of signal RB is normally supplied-with current from the secondary 5 of a transformer T, the primaryfiofwhich-is continuouslysupplied with alternating currentffrom a transmission line not shown. The circuitfor the light 4. extends fromtone-termina-l of' the secondary 5 through the backcontact LBBP of a relay LBBP associated with-the westbound signal LB as will be described later, front. contact 8 off a power-off relay PT whose. winding ispermanently connected to secondary 5', light 4' and front contact 9' to the other terminal'ofxsecondary 5. In' case of a loss of power from the transmission line, the relay PT is.deenergized' and its contacts 8 and 9 drop into engagement with back contacts. and the light. 4 is then supplied from a local standby source of direct current not shown, but whose terminals aredesignate d by the reference characters X and Y; The light circuit now extends from the positive terminal of the source of direct current, back contact. RBGE of a relay RBGE to. be referred to later,

resistance unit 11,,back. contact '8 of relay PT, light 4, back contact Q'and. to the negative terminal Y. of the source of direct current; As will appear later, the. back contacts LBBP 'and RBGE are closedonly upon the'approach of a train and thus the signal RB is approach lighted both when'the source of current is the alternating currenttransmissionline' and when the" localstandby direct current source is" active; The' lighting circuits forithe westbound signal LB'at'the samelocation B are shownin Fig. land are similar'to those just describedforthe signal RB, an'dthusit is thought notnecessary to describethem in detail. It is'to be" noted, however, that the alternating" current circuitisnormallyheld openat the backcontact RBBP 'of:a relay RBBP associated-with the eastbound signal RB, and thecircuit to thedirect current source is'normally" held open at the back contact LBGE of a relayLBGE associated with acontrol'circuit for signal LC to the rear'of signal LBlas will appear as'the'specification progresses. As the light circuits for-the'other'signals of my system-are similar tothose described for the signals at thelocation'B andasthese ligi t circuits form nopart of my-invention, the light circuits for the'remainingisignals are not shown in the drawings for-thesake'ofsimplicity. Attention is called to'thefact, however; that at any intermediate signal location such as'looation C, the relay LCBP associated with the westbound signal LC is-normally deenergized at a time when the signal RC is cleared for eastbound traffic in a manner to be later pointed out. Thus the light circuit not shown for the signal RC, which includes a back contact of the relay LCBP in the same manner that the light circuit for the signal LB includes the back contact RBBP is closed normally and the light continually illuminated. When the local standby source of current is active, however, at such locations, the signal is approach lighted inthe samemanner as isdescribed'above'for the signal RB.

Associated with each wayside signal are two relays designated by the reference characters HD and NP with prefixes corresponding to the signal. Referring to signal RB, the relay RBI-ID is supplied with currentfrom the positive terminal X of the local source of current through the controller 18 in either its lower position corresponding to the clear position of signal RB or through its upper position corresponding to the caution position of signal RB, and the winding of the relay to the negative terminal Y of the source of current. The relay RBNP is supplied with current from the positive terminal X through controller 19 in its center position corresponding to the stop position of signal RB and the winding of relay RBNP to the negative terminal Y. It follows that relay RBI-ID is energized under'both' the clear and caution positions of signal RB and" deenergized under the stop position, while relay,

RBNP is energized only when signal RB" indicates stop. The relay RBI-ID is made slowreleasing in order that it will remain energized during the-interval the signal RB is moved from its caution to clear position or from its clear to caution position.

Each wayside signal is provided with a control circuit. Looking at signal LC of Fig. 2, for example, the control circuit for this signalcan be traced from the battery 21 at location B through the winding of the low resistance relay LBGE,

front contact RBNP of relay RBNP associated with the signal RB, back contact 23 of relay LBI-ID, front contact B1TR of track relay BlTR',

line wire 24, frontcontact C2TR of track relay CZTR, front contactWFC of a directional relay WFC to be described later, field. winding 27 of signal LC, line wire 28, back contact 29 of relay LBHD and to the opposite terminal of battery 21. It is to be noted that this control circuit for signal LC is governed by the directional relay WFC, by the track. circuits for the track block BC and by the relay RBNP governedby the position of the opposing signal RB. The polarity of the current supplied to this control circuit for signal LC is governedby the relay LBl-ID'associated with the westbound signal LB in advance. With the signal LB at stop and relay LEI-ID deenergized, the current is of one polarity and. when signal LB is operated to its caution or clear position and relay LBHD energized, the current supplied to the control circuit for signal LC is of a reverse polarity. That is to say, signal LC will display a.

clear indication when the signalLB in advance displays either caution or clear and will display a caution indication when signal LB is at stop. When the immediate track sections in advance of signal LC are occupied or the opposing signal RB. cleared, signal LC is set at stop. Also, the signal LC is manually controlled by means of the directional relay WFC as will shortly appear.

The'winding' of the low resistance relay LBGE being in series with the control circuit for the signal LC, it will be energized whenever that circuit is closed. The relay LBGE is also'provided, however, with an additional energizing circuit that includes battery 21, winding of relay LBGE, front contact RBBP of the relay RBBP, high resistance31 and back to the battery 21. Except under trafnc conditions to be later described, the relay LBGE is'retained energized by this last circuit irrespective of the condition of the control circuit for signal LC. 7

Each signal of my system'is governed by a control circuit similar to that just described for the signal LC except at certain locations as will now be'poi'nted out. The control circuit for the starting signals RAl and RA2 at the passing siding P1 receives current from the battery 32 at location B through the winding of the relay RBGE., front contact LBNP of the relay LBNP, pole-changing contact 114 of relay RBHD, a track circuit controlled contact BZTR. of track relayB2TR, front contact lilFB of a directional relay EFB to be shortly described, front contact A1TR 'of track relay AlTR, front contact A2'I'R of track relay A2TR, front, contact GB of the direction con-- trolling relay GR, polar contact GR, frontcon tact ISKR of relay ISKR, polar contact ISKR,

field winding 41 ofsignal'RAl and back to' the battery 32 over the line wire 42 through the polechanging contact115. With the polar contact ISKR shifted to the left-hand position in response to the positioning of the switch 18 for trafiic to the siding P1, this control circuit is then connected tothe field winding 43 of the signal RA2 aswill be readily understood from Fig. 1. The control circuit forrthe starting signals LEl I and LE2 at the passingsiding P2 is modified from that "described for the intermediate signals by the including of a contact 44 of a traffic direction controlling lever 45 and by havingthe circuit first control a polarized relay 46in place of the field winding of the signals directly. With relay 46 energized by one polarity of. current, a circuit is closed from the positive terminal X of ,a local source of current through the right-hand polar contact 47, front contact 48, a contact 49 governed by a lever of an interlocking machine not shown, in the usual manner, front contact 25KB, righthandpolar contact 2SKR field winding 52 of j signal LE front contact 53, right-hand polar contact 54 of relay 46 and to the negative terminal Y. With relay 46 energized by current of va reverse'polarity then the current supplied to the field winding 52 will be, in turn, of reverse polarity. When the switchZS is set for trafiic to the siding P2, the polar contact 2SKR is reversed and relay 46 then controls the field winding 55 of signal LE2. V

Across the signal control circuit, in parallel with the field winding of each intermediate signal, is connected the winding of a relay designated by the reference character BP plus a prefix corresponding to the signal. This relay, however, is connected across the control circuit in advance of the front contact governed by the directional relay. Referring to location C, the relay LCBP associated with the control circuit for signal LC' described above is connected to the line wire 24' directional relay WFC, the relay LCBP is governed by trafiic conditions alone. As stated above, the control circuit m each intermediate signal governs a relay BP in the same manner as just described for' relay LCBP.

In the figures the apparatus is shown set for eastbound trafiic. The manner of establishing the direction of trafiic will now be described. Each track block is provided with a traffic control 'circuit and two directional relays, one for each direction of traffic, designated by the reference character F plus a prefix corresponding to the direction and a suffix corresponding to the location. These trafiic control circuits are governed by a trafiic direction controlling device located at each of the opposite ends of the stretch of railway. At the passing siding P1, the trafiic direction controlling device is the polarized direct current relay GR which is so constructed in a manner Well known to the art that its polar cona matter of fact, the relay GRmay be replaced] by a controller actuated by a lever of an interlocking machine should it seem desirable to do so. At the siding location'P2, the traffic direction controlling device is shown in the form of a' manually operated lever 45 which actuates the controller contacts 44 and 56. Should it seem desirable to do so this lever 45 may be replaced by a relay similar to the relay GR at the opposite end' of the stretch. When lever 45 occupies its right hand position, that is, the position shown in Fig. 3,'the contact 56 engages both contact springs 57 and 58. When lever 45 is shifted to its center position or to its left-hand position, the contact 56 becomes disengaged from spring 58 and the circuit controlled thereby is opened.

To establish eastbound traflic the operation must begin at the east end of the stretch and proceed as follows: Assuming the track block D--E to be unoccupied, the relay RDBP at the signal location D will be energized, as will be evident by an inspection of Fig. 3 due to the fact that the front contacts DlTR EZTR and ElTR of track relays DlTR, E2TR and ElTR, respectively, are closed. The operator moves the trafl'ic'direction controlling lever 45 to its right-hand position and current is supplied from battery 65 through the front contacts LE2NP and LE1NP in series, contact spring 5'7, contact 56, contact spring 58, linewire 66, back contact 67 of westbound directional relay WFD, front contact RDBP of relay RDBP, winding of eastbound directional relay EFD and line wire 68 back to the battery 65. As directional relay EFD becomes energized, it closes at its front contact 69 a stick circuit around the front contact RDBP. That is to say, the directional relay EFD can be picked up only in the event the track block D-E is unoccupied and the westbound starting signals LE1 and LE2 are at stop, but once it is picked up, a stick circuit is closed that retains the directional relay EFD energized regardless of the trafiic conditions of the track block D-E. As directional relay EFD is energized, it also closes front contact EFD'"! included in the signal control circuit for the signal RD and that signal is then operated to either its caution or clear position depending upon the polarity of the current supplied to its control circuit as determined by the position of relay REI-ID' associatedwith the signal RE in advance.

With track block CD unoccupied so that'its:

track relays ClTR and DZTR are both picked up toclose contacts ClTR and D2TR respectively, and the westbound signal LD is at stop so that the relay LDNP is energized to close front contact LDNP the relay RCBP at location C is energized by the control circuit of signal RC. Under these circumstances the energizing of the directional relay EFD closes the traffic control circuit for the block CD from battery '74 through front contact '75 of relay EFD, line wire 76, back contact '77 of the Westbound directional relay WFC, front contact RCBP winding of relay EFC, line wire '79, front contact 80 and to the opposite terminal of battery 74. As the directional relay EFC picks up, the stick circuit through its own front contact 113 is closed around the front contact RC'BP to retain this directional relay energized regardless of track conditions for the block C-D. Again it is to be noted that before the'eastbound directional relay EFC can be energized both the traffic conditions for the track blockC-D and the position of the opposing westbound signal LD are checked but after the relay EFC is once energized, neither the position of signal LD nor the traffic conditions of the block C-D affect the relay. As directional relay EFC is picked up, the front'contact EFC is closed to complete the signal control circuit to signal RC and that signal is operated inaccordance with the position of therelayRDI-ID for the signal RD in advance.

With the track block B-C unoccupied and the westbound signal LC at stop, current is'supplied to the relay RBBP at location B by the control circuit for signal BB in the same-manner as de-- scribedfor the relay RCBP at the location C and relay RBBP energized to close the front contact.

RBBP included in the circuit for relay EF'B. Under these circumstances current flows-from the battery 83 at location C through a traffic control circuit that includes the

front contacts

84 and 85 of directional relay EFC to energize the eastbound directional relay EFB at location B. This trai'fic control circuit is similar to that already describedfor the relay EFC and can be easily traced. As directional relay EFB picks up, a stick circuit is closed through its own front contact 86 to retain this relay energized regardless of traffic conditions for the track block BC or of the position of the opposing signal LC. The energizing of relay EFB closes the front contact EF'B in the control circuit for signal RB and current is supplied to the field winding 17 of signal RB to operate that signal in accordance with the position of the signal RC in advance.

Assuming the track block AB to be unoccupied and that the operator has energized the direction controlling relay GR with normal polarity of current to close the contacts GR and GR The energizing of the directional relay EFB closes the contact EFB and thus completes the signal control circuit to signals RAl and RA2; the circuit being closed to field winding 41 of signal RAl if the switch is is set for main line traffic and closed to field winding 43 of signal RA2 if switch 18 is reversed for trafiic to the siding P1.

To sum up thus far, the setting of the direction controlling devices at each end of the stretch of railway in a position corresponding to eastbound traffic causes the traffic control circuits, starting at the east end of the stretch, to be closed successively to energize in turn an eastbound directional relay at each signal location,

if each successive track section of the stretch" is unoccupied and each successive opposing westbound signal is set at stop. When once the di-- rectional relays are energized, they are retained energized by stick circuits that make them free from the control of traffic conditions of the track sections and also free from the control exerted by the position of the opposing westbound signals. The energizing of each directional'relay completes a signal control circuit for a corresponding eastbound signal to clear that signal in accordance with traffic conditions in advance. It will be noted that while the operator of the relay GR has control over the starting eastbound signals RAl and RA2, he has no control over the remaining eastbound signals once they have been cleared for an eastbound train. Also it is to be noted that due to the fact the pick-up circuit for the track relay AZTR is controlled through the back contact GR of the relay GR, it is necessary for the operator of relay GR, to, actuate that relay in order to clear either starting signal RAl or RAZ for each following eastbound train as well as for the first eastbound train.- It is evident that once eastbound. trafiic has been established, all following eastbound trainswill be governed by the automatic signals in accordance with trafiic conditions in advance in the same manner as obtained in the usual three-block automatic signal system. As each.

eastbound train leaves location A, the shunting of the relay AlTR opens front contact A1TR and deenergizes the relay LBBP to approach light the signal RB by closing the back. contact LBBP" when the normal alternating current source of current is active. In case thereis a loss of alternating current power, the signal RB is approach lighted by the standby current source through the back contact RBGE due to the fact that as relay LBBP becomes deenergized, the

front contact LBBP is opened and relay RBGE deenergized inasmuch as the eastbound train has shunted the track relay AZTR to also. open front contact AZTR To reverse the direction of traiiic from that for eastbound trains, in which condition theapparatus of Figs. 1, 2 and 3 is shown, to that for westboundtrains, the operator of lever 45 must first reverse the lever to open the circuit to the directional relay EFD. The deenergizing of relay EFD sets-signal RD at stop and opens the circuit to relay EFC at the contacts '75 and 80. Relay EFC, in turn, is deenergized to set the signal RC at stop and open the circuit to the directional relay EFB. As relay EFB becomes deenergized, the signal RB is set at stop and the control circuit to the signals RAl and RA2 openedv at contact EFB to hold thesesignals at stop. Assuming that there is no train occupyingthe stretch between the sidings each BP relay associated with the westbound signal control circuits will be energized due to'the fact that the track relays are all picked up and each NP relay associated with the eastbound signals are now energized checking the stop position of the eastbound signals. The operator-at the siding Pl, that is, at the west end of the stretch, energizes the traflic direction controlling relay GR by current of reverse polarity so that contact 95 is made to engage its left-hand contact and current flows from the battery 96 through contact 97 of relay RNP, left-hand contact 95, line wire 98, back contact 99 of the eastbound directional relay EFB, front contact LBBP winding of directional 21,9 4,840 relay and line .wire 101 back to the battery 96. As relay WFB picks up, its stick circuit is closed at front contact 102 to retain that relay energized irrespective of trafiic conditions of the track block A-B. The signal control circuit for signal LB is now completed at the front contact 4 WFB and that signal operated to either the caution or clear position depending upon the position of the signal LA in advance. The energizing of the directional relay WFB also closesthe trafiic control circuit for the block B-C from the battery 103 to thedirectional relay WFC at the front contacts 104 .and 105 as will be easily traced. This trafiic control circuit being completed through the front contact LCBP of relay LCBP if the opposing eastbound signal RB is at stop so that the contact RBNP of relay RBNP is closed and track relays BlTR and C2TR are picked up to close contacts B1TR and C2TR respectively. As directional relay WFC picks up, it closes its stick circuit at the contact 10'? around the front contact LCBP so that this relay is now retained closed irrespective of the trafiic conditions of the track block B-C or of the position of the opposing signal RB. The

signal control circuit for signal LC is now completed at the front contact WFC and that signal operated in'accordance with the position of the relay LBHD for signal LB. The energizing of relay WFCalso completes the trafiic control circult to the. directional relay WFD at the front contacts '77 and 10350 that that relay is now supplied with current from the battery 83 through the front contact LDBP if block CD is unoccupied and signal R .at stop.v As relay WFD is energized, its stick circuit is closed at the contact 109 and it is held energized irrespective of trafilc conditions in the track block C'D or of the position of the opposing signal RC. The contact WFD is now closed to complete'the control circuit for the signal LD and that signal operated in accordancefiwith' the position of the relay LCHD for the signal -LC. As relay WFD picks up, the control circuit for the relay 46 is also closed at the contact WFD. contact 1l1-44112 being closed because lever 45 is in its reversed position, and that relay energized in accordance with the position of the relay LDHD for the signal LD. Theenergizingof the relay 46 permits current to be supplied to either the signal LE1 or LE2 as determined-by the position of the switch 2S, it being understood, of course, that the lever controlled contact 49 is closed at this time. 'With westbound traflic thus established, westbound trains can advance from the location E at the passing siding P2 under the protection of the westbound signals which are now controlled in the usual manner for a threeblock automatic signal system; the westbound directional relays remaining energized through the medium of their stick circuits irrespective of the traflic conditions or of the position of the eastbound signals.

It follows from the foregoing description that in establishing agiven direction of traffic, the directional relays corresponding to the direction of trafiic to be established can be energized only in the event each track section is unoccupied and the opposing signals all in the stop position. Once the direction of trailic isestablished the directional relays remain energized irrespective of the trafiic conditions. It is to be noted also that a directional relay can be energized only in the event the opposing directional relay at the same location. is deenergized. For example, the cir- -position for a few seconds.

cuit to relay WFC is controlled by the back contact 84 of the directional relay EEG and the circuit for the relay EFC is likewise controlled by the back contact 77 of relay WFC.

In the case it is desired to have two trains meet at the siding P3 located in the track block C--D, with the westbound train taking the siding, the procedure is as follows: The two operators will first set the relay GR and the lever 45 in the positions to establish westbound traflic in the manner described above and the westbound train advanced from the location E to siding P3 by the clearing of the westbound signals. As this train clears the main track at the siding P3, the operators set the relayGR and the lever 45 in the position to establish eastbound traffic and the eastbound train advanced to the siding P3 by the clearing of the eastbound signals. In order to permit the westbound train to leave the siding P3 and advance west as soon as the eastbound train passes the west end of siding P3, the operator of the lever 45 will place the lever in the center This will drop the eastbound directional relays and then if the operator of the relay GR reverses that relay, the westbound directional relays will be energized up to the track block 0-D occupied by the east- ,bound'train to clear the westbound signals from signal LC to the location A. The operator of the lever 45 again places this lever in the right-hand position which reenergizes the directional relay EFD to again clear the signal RD for the eastbound train. It follows that these two trains can advance in their corresponding directions from the siding P3 under full signal protection. It

would be necessary for the crew of the train on the siding P3 to advise the. operators when to execute this operation but this could easily be accomplished by telephone without delay to either train. If the eastbound train is to take siding at P3 the procedure is to establish eastbound traffic to allow the eastbound train to advance to siding P3 and then reverse the direction of traffic and advance the westbound train. If a work train ora pusher engine stops at any intermediate point between the two sidings P1 and P2, the operators can reverse the direction of traific to permit this work train or pusher engineto return to its starting point under full protection of the signals. Once the direction of traffic is established to advance an eastbound train from the siding P1, switching movements can be made at the west end of the siding P2 without interfering with the eastbound direction of traffic established and thus without delaying the eastbound train but still providing it with the usual automatic signal protection as it approaches the siding P2. In the same manner, switching movements can be made at the east end of the siding Pl after westbound traific has been'established .for a westbound train.

Such a signalsystem as here disclosed checks the occupancy of each track section and the stop position of each opposing signal before the direction of trafiic can beestablished. Once the direction of traflic is, established the system is free from the danger of a loss of traffic direction due to the possible momentary loss of shunt of a track circuit by. a light engine or motor car. Trains may meet at intermediate points and then proceed in opposite directions from the meeting point without delay to either train and under full automatic signal protection. A train may reverse its direction of travel at any intermediate point and the operators establish the direction of trafiic corresponding to this reverse movement. Once a train has entered the stretch of railway no opposing train movement can be authorized until the occupying train has cleared the stretch of railway. The direction controlling device may be operated by a centralized trafiic control system, a remote control system, or by a local circuit. In fact, any one system may be used to control the traific controlling device at one end of the stretch and a dissimilar system used to control the traiiic controlling device at the other end.

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

Having thus described my invention, what I claim is:

1. A railway signal system including, a stretch of railway track arranged in track sections, signals located at intervals for governing traffic in one direction through the stretch and other signals located at intervals for governing traffic in the other direction through the stretch, a directional relay for each signal adapted when energized to clear said signal, circuit means to control the directional relays arranged to effect the energizing of the relays associated with the signals governing traiiic in a given direction only when each track section is unoccupied and each signal governing traflic in the opposite direction is at stop, and means effective when the directional relays for a given direction of traffic are energized to retain said relays energized irrespective of the traffic conditions of the track sections.

2. A railway signal system including, a stretch of railway track arranged in track sections, signals located at intervals for governing trafiic in one direction through =the stretch'and other signals located at intervals for governing 'trafiic in the other direction through the stretch, a directional relay for each signal adapted when energized to clear said signal, circuit means to control the directional relays arranged to eficct the energizing of the relays associated with the signals governing trafiic in a given direction only wheneach track section is unoccupied and each signal governing traffic in the opposite direction is at stop, and means effective when the directional relays for a given direction of traffic are energized to retain said relays energized irrespective of the traffic conditions of the track sections or of the position of the opposing signals.

3. A railway signal system including, a stretch of railway track arranged in track sections, signals located at intervals for governing traflic in one direction through the stretch and other signals located at intervals for governing traific in the other direction through the stretch, a directional relay for each signal adapted when energized to clear said signal, circuit means to control the directional relays arranged to effect the energizing of the relays associated with the signals governing trafiic in a given direction only when each track section is unoccupied, and a stick circuit for each relay efiective when the directional relays for a given direction of traflic are once energized to retain its relay energized irrespective of the traffic conditions of the track sections.

4. A railway signal system including, a stretch of railway track arranged in track sections, signals located at intervals ion-governing traffic in one direction through the stretch and other signals located at intervals for governing tramc in the other direction through the stretch, a directional relay for each signal-adapted when energized to clear said signal, a manually'controlled circuit means to control the directional relays capable of energizing the relays associated with the signals governing traffic in one direction orenergizingthe relays associated with'the signals governing traffic in the other direction only when-each track section is unoccupied, and thereby clear the signals for one direction or the other, and a stick circuit 'for each relay effective when'the directional relays for a given direction of traflic ar'eonce'energized toretain its relay energized irrespective of'the traflic conditions of the track sections.

5. A railwaysignal system including, a stretch of railway, signals located at opposite ends of the "stretch to govern trafiic in opposite direc- "tions through the stretch, a control circuit for each signal responsiveto traffic conditions'ofthe stretch, a traiiic direction controlling circuit, a

directional relay for each signal adapted when energized to clear the signal controlled jointly by the traffic direction controlling circuit and the control circuit for the same signal, means -rendered effective to control=a directional relay by the traflic direction controlling circuit only,

once the relay is energized, and'a manually operated device to control thet'raflic direction controlling circuit.

6. A railway signal system'including, a stretch of railway, signalslocated 'atopposite ends ofthe stretch to govern tr'afiic in opposite directions throughthe stretch,-a c'ontrol circuit for each signal "responsive 'to trafiic conditions of the stretch, a directional relay for each signaL-a' traffic direction controlling circuit, means controlled jointlyby the control-circuit of a signal and the trafiic direction controlling circuit to "energize the directional relay associated with'that-signal, means controlled jointly-by the control circuit and the directional relay to clear the "signal, means to a'nnul the'control of'the control circuit over the directional relay once said relay-is set to clear its signal, andmanuall'y operated devices to control said trafiic direction controlling circuit.

7. A railway signal: system including; a' stretch of; railway arranged in a plurality of track blocks, a signal located at each-end of a track block to govern traffic in opposite directions-through the block, a trafiic direction controlling circuit for each track block for controlling the-signals, traffic controlled means for each track block responsive to traflic conditions of the block, arnanually operated device adapted to act in conjunction with the trafiic controlled means'for causing the traffic direction controlling circuits to establish a given direction of traflic through the stretch, and means associated'with'each trafiic direction controlling circuit to annul the control of the trafiic'controlled means over said tramc direction controlling circuit once the direction of trafiic has been established.

8. A railway signal system including-a stretch of railway arranged in a plurality of track-blocks, a signallooated at each end of a traclrblockto governtraffic in opposite directions through the block, a traffic'direction controlling-circuit' for each track block for controlling the. signals; traffic controlledvmeansfor each trackblock-responsive to ,trafiic conditions of the block/1 a circuit controlling device for each signal governed by the position of the signal, a manually operated device adapted to act in conjunction with the traflic controlled means and the circuit controlling devices for causing the trafiic direction controlling circuits to establish a given direction of trafiic through said stretch, and means associated with each traflic direction controlling circuit to annul the control of the trafiic controlled means and the circuit controlling devices over said traffic direction controlling circuit once the direction of traffic has been established.

9. A railway signal system including, a stretch of railway over which trafiic normally moves in either direction, a first set of signals located at intervals to govern trains through the stretch in one direction, a second set of signals located at intervals to govern trains through the stretch in the opposite direction and arranged that there is a signal of the second set located opposite each signal of the first set, traflic direction controlling circuit means to selectively control said first and second set of signals arranged to clear the signals of a set by starting at the remote end of the stretch and clearing the signals successively, a signal device controlling said traffic direction controlling circuit means to check the stop indication of the opposing signal of each of the successive signals of the set selected before the signal can be cleared, and means controlled by said trafiic direction controlling circuit means to annul the control of said traiiic direction controlling circuit means by said signal device once a set of signals has been cleared.

10. A railway signal system including, a stretch of railway, a first set of signals located at intervals to govern tramc in one direction through the stretch, a second set of signals located at intervals to govern trafiic in the opposite direction through the stretch, a control circuit for each signal responsive to trafiic conditions in advance of the signal, and a manually controlled circuit means to establish the direction of traffic adapted to act in conjunction with the control circuits to selectively clear one or the other of saidset of signals when said stretch is unoccupied to permit a train to enter said stretch, said manually controlled circuit means capable of reversing the direction of trafiic to the rear of a train occupying any intermediate point of the stretchand act in conjunction with the control circuits to clear the opposing signals in the rear of saidtrain and thereby permit a train to travel in the reverse direction from said intermediate point.

11. A railway signal system including, a stretch of railway, a first set of signals located at intervals to govern traffic in one direction through the stretch, a second set of signals located at intervals to govern traffic in the opposite direction through the stretch, a track circuit for each signal responsive to trafiic conditions in advance of the signal, and a manually controlled means to establish the direction of traffic adapted to act in conjunction with the track circuits to selectively clear one or the other of said set of signals when said stretch is unoccupied to permit a train to traverse said stretch, said manually controlled means capable of reversing the direction of traffic to the rear of a train occupying any intermediate point of the stretch and cooperate with said track circuits to clear the opposing signal to the rear of said train and thereby intervals to govern traffic permit traffic in the reverse direction from said intermediate point.

12. In combination, a stretch of railway track, a signal at each end of the stretch to govern trafic in opposite directions through the stretch, a trafiic locking circuit for the stretch divided into a plurality of different sections, a source of current and a relay at each end of the stretch, manually controlled means at each end of the stretch to connect either the current source or the relay at such end to the trafiic locking circuit, repeating means at each junction of adjacent sections of the traiiic locking circuit including two directional relays controlled by said circuit and arranged to supply current to the left-hand section in response to control by current from the right-hand section or to supply current to the right-hand section in response to control by current from the left-hand section for energizing the relay at the end of the stretch opposite that at which the current source is connected to the trafiic locking circuit, and means controlled by the relay at each end of the stretch for governing the signal located at its end.

13. A railway signal system including, a stretch of railway, a first set of signals located at intervals to govern traffic in one direction through the stretch, a second set of signals located at intervals to govern traffic in the opposite direction through the stretch, a signal control circuit for each signal responsive to trafiic conditions in advance of the signal, a trafiic control circuit for each signal, manually controlled means for governing the trafiic control circuits to select the direction of traffic, and means controlled jointly by the traific control circuits and the signal control circuits to selectively clear the set of signals corresponding to the direction selected by the manually controlled means, and said traffic control circuits arranged in such a manner as to permit the manually controlled means to reverse the direction of trafiic to the rear of a train occupying any intermediate point of the stretch whereby the signals will be cleared for a train to move in the reverse direction from said intermediate point.

14. A railway signal system including, a stretch of railway, a first set of signals located at in one direction through the stretch, a second set of signals located at intervals to govern trafiic in the opposite direction through the stretch, a control circuit for each signal responsive to trafiic conditions in advance of the signal, a traffic control circuit for the stretch and divided into a plurality of different sections, two directional relays located at each junction of adjacent sections of the trafiic control circuit, manually controlled means to govern the trafiic control circuit to selectively energize the directional relays at each junction to establish the direction of traffic, means controlled jointly by the directional relays and said control circuits to selectively clear one set or the other of said signals, and said traific control circuit arranged in such a manner as to permit the manually controlled means to reverse the selection of the directional relays at all junctions to the rear of a train occupying any intermediate point of the stretch whereby the opposing signals may be cleared for a train to move in the reverse direction from said intermediate point.

JAMES A. PARKINSON.