US2312740A - Railway traffic controlling apparatus - Google Patents

Description

March 2, 1943- .1. J. VANHORN RAILWAY TRAFFIC CONTROLLING' APPARATUS Filed July 1o, 1941 '2 sheets-sheet 1 @www E@ WMIMI INVENTOR JaImsuS7 J Vllhorn HIS A'rToRNEY March 2, 1943. J. J. VANHORN 2,312,740'

RAILWAY TRAFFIC CONTROLIJNG APPARATUS I Filed July 1o, 1941 2 sheets-sheet 2" Patented Mar. 2, 1943 RAILWAY TRAFFIC CONTROLLING APPARATUS J ames J. Vanhorn, Pittsburgh, Pa., assigner to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application July l0, 1941, Serial No. 401,757

(ci. 24e- 26) l Claims.

` My invention relates to railway trafc conjtrolling apparatus, and more particularly to apparatus for control of track indicators.

The o'ice of a remote control system for a railway is usually provided with a track model of the stretch of track associated with such control system, and track indicators in the form of small electric lamps are placed on such track model one for each of certain designated track sections of the stretch. Each such lamp is illuminated through the medium of the control system when the respective track section is occupied in order that the operator may know the location of the trains operating over the stretch. Wayside signals associated with track switches of passing sidings when governed by such remote control system are usually provided with approach locking which is controlled in part by approach relays, each of which relays is controlled by the track relay of one or more track sections in the approach to the respective signal. It is customary to use the approach relays as means for controlling track indicators, each such approach relay when deencrgized in response to a train occupying the respective track section or sections, causing the remote control system to transmit an indication influence to the remote oice where it results in a respective indication relay being energized and picked up to complete a circuit for the track model indicator lamp that corresponds to the same track section or sections. In this manner the operator is informed when a train is approaching a signal at which the operator can hold the train by setting the signal at stop or can advance the train by clearing the signal. When the remote control system is a centralized traffic control system of the time code type, the number of track occupied indication codes that can be provided without increas-` ing the usual coding units and other apparatus is limited.' In such centralized trafuc control system for single track railroads it is desirable to provide track occupied indications for the track section or sections between adjacent passing sidings and for the track section or sections between the two ends of a siding.

In view of the above discussed circumstances in railway signaling systems, a feature of my invention is the provision of railway trailic controlling apparatus incorporating novel means for providing track occupied indications in centralized traine control systems for railroads.

y Another feature of my invention is the provision in centralized trafiic control systems for single track railroads of novel means for indieating at the voffice occupancy of the track stretch between the adjacent entering signals of adja-` cent sidings, and occupancy of the track stretch between the leaving signals at the two ends of a siding.

Again, a feature of my inventionis the provision of novel and improved means for remote control systems for railways wherewith the occupancy of the stretch of track between adjacent sidings or ,between the two endsof a siding is indicated by the present equipment andvadditional repeater relays controlled over line circuits requiring line wires are avoided.

The above features of my invention, as Well as other advantages which will become apparent from the following specification, are attained by controlling a track indicator corresponding to the stretch of trackv between adjacent passing sidings, or corresponding to the stretch of track between the two ends of a siding, over a circuit which includes in Aseries a front contact of eachY of two indication relays, one governed by each of the two approach relays associated with signals of vsuch stretchof track. Inthe case of a stretch betweenadjacentsidings, the approach relay of each of the two adjacent entering signals associated with such sidings is controlled over the track relay of each track section intermediate such entering signals as well as over the track relays of other sections in the approach to the respective signal. Each approach relay when deenergized due to a train approaching the respective signal causes an indication code to be transmitted to the office where a corresponding indication relay is energized and picked up.

Since under such arrangement the only traffic condition under which the two approach relays of the two adjacent entering signals for adjacent sidings are deenergized at the same time is when the stretch of track between such signals is occu-l pied, the indicator controlled over a circuit in cluding a front contact of each of the two respective indication relays indicates a track occupied condition for this stretch of track only. I provide a directional stick relay for each approach relay for by-passing the control of the approach relay around the contact of the track relay of the usual detector track section for trains moving in the direction opposite to that governed `by the assotion relaysgoverned by the two approach relays of the two leaving signals of such siding. Again,

since the only condition in which the two approach relays are released at the same time is when a train occupies the stretch between the two leaving signals, such indicator is displayed only in response to occupancy of this stretch between the two ends of the siding.

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

In the accompanying drawings, Fig. 1 is a diagrammatic view showing one form of apparatus embodying my invention when used to indicate occupancy of a stretch of track between two ladjacent sidings of a single track railway, and Fig. 2 is a diagrammatic view showing one form of apparatus embodying my invention when .used to indicate occupancy of a stretch of track between the two ends of a passing siding of a single track railway. In each of the two views like reference characters are used to designate similar parts.

Referring to Fig. 1, the reference character .F designates a stretchof single track railway which is lprovided with track switches 5S and 1S leading to sidings Fa and Fb. I'hat is, track switches 5S and 'IS are the adjacent switches of sidings Fa and Fb.

This stretch of track F is divided by the usual insulated rail joints` into track sections 6T, 5T, AST, 1T and 8T; the track sections 5T and 1T being detector track sections at switches 5S and 1S, respectively. Each such track sections is provided with a track circuit comprising a battery 2 connected across the rails. at one end of the section, and atrack relay .designated by the reference character R plus a preiix corresponding to the associated section connected across .the rails at the other end of thefsection.

Each track switch 5S and 'IS is provided with the usual protecting signals, switch 5S being associated with entering signal LS andleaving signals R6 and RCS, and switch 'IS being associated with entering signal R8 and leaving signals L8 and LCB. These signals may be of any standard .type and are shown by the usual conventional symbols, it being observed that entering signals L6 and R8 and leaving signals R6 and L3 comprise two signal mechanisms mounted on a single mast. Only certain of the control and voperating circuits for these signals` of Fig. 1 are shown for the Vsake of simplicity since such circuits form no part of my invention and all of them are not required for a full understanding of the invention. Itis sufficient for this application to point out that these signals associated with the track switches are controlled in part by a centralized traic control system to be described hereinafter and would also be .controlled by trailic conditions of the stretch. It is to be noted that although the stretch of .track between entering signals L6 and R8 is shown as consisting of but one track section AST and no intermediate signals are provided it is to be understood that this portion of track may be formed into a plurality of track sections and intermediate signals may be located at selected points if desired. In the arrangement here shown, leaving signal LAS serves as an approach signal for entering signal L6 and leaving signal RAS serves as an `approach signal for entering signal R8.

It should -be pointed out at thisv time that in order to simplify the drawings, certain contacts of the several ,relays are shown remote from the relay winding and certain contacts of other .devices are shown remote from the device. In each such instance the contact is identified by the reference character for the relay or device ybeing located adjacent thereto and by the contact being shown in the position corresponding to the normal position of the relay or device.

The signal R8 is provided with an approach over front contacts l0, il and l2 of track relays `STR, ETR and ASTR, respectively, winding of relay RBAR, front contacts I3, I4 and i5 of relays ASTR, 5TR and ETR, respectively, and to terminal C of the same source of current. Thus approach relay RSAR associated with entering signal R3 at siding lFb is controlled by the track relay of detector track section 5T at the next adjacent passing siding Fa and by the track relay of section 'BT in the approach to the leaving signal R6 at siding Fa as well as by the track relay of intermediate section AET. In order to provide proper control of approach vrelay RSAR under the various traic conditions atvswitch 5S, contacts l0 and i5 of track relay GTR lvare by-passed by contacts I8 and 19, respectively, closed when signal RAS is set at stop. Furthermore, front contacts l1 and 20 of a directional relay LGS to lbe referred to later, and front contacts i3 and 2! of a relay SRWP also to be referred to later com- .plete shunt paths for ley-passing the circuit of approachrelay RBAR around the control of track relays -BTR and BI'R as will be understood by an inspection .of Fig. 1. It is to be seen therefore that approach relay RSAR is energized and picked up when track sections 6T, 5T and ABT in the approach to signal R8 are unoccupied; when scftions 6T and AST are unoccupied and section 5T is occupied .if directional stick relay LSS is picked up closing front contacts Il and 2B; when sec tions 5T and AET are unoccupied and section EST is occupied providing signal L5 is set at stop closing contacts i6 and l 9, and also when section AST is unoccupied and relay SRWP is picked up closing front contacts I8 and 2l, irrespective oi the traic condition of sections 6T and 5T.

Approach relay LBAR is included in a normal circuit that passes from terminal B over front contacts 24, 25 and 26 of track relays BTR, TTR

and ASTR., respectively, winding of relay LAR, front contacts 21, 28 and 29 of relays AETR, ITB, and BTR, respectively, and to terminal C. Thus approach relay LSAR associated with entering signal L6 at siding Fa is controlled by the track relay of the detector track section 1T at the adjacent siding Fb and the relay of section 8T in the approach to the leaving signal L8 at siding Fb as well as by the track relay of intermediate section AST. In order to provide proper control of approach relay LSAR ifor the different traiilc conditions at switch ,'IS, front contacts 25 and 29 of track relay 8TH. are by-passed by contacts 3S and 33, respectively, which are closed when signal LA8 is set at stop; front contacts 25 and 28 of track relay [TR are by-passed by front contacts 3| and 34, respectively, of a directional stick ref lay RBS, to be shortly described; and contacts of both track relays 8TR and 'ITR are by-passed by shunt paths including front contacts 32 and 35 of a relay IRWR also to be shortly described. Consequently, approach control relay I iJAR is energized and 4picked up when sections 8T, 7T and AST in the approach to signal L3 are unoccupied; when sections 8T and AT are unoccupied and section TT is occupied, providing directional relay RSS is picked up closing front contacts y3l and S; when sections ABT and 1T are unoccupied and section 8T is occupied providing signal LAB is set at stop closing contacts 30 and 33; and when section AST is unoccupied, and relay 'ERWP is picked up closing front contacts 32 and 35.

From the foregoing description of the control of approach relays RSAR and LSAR it is to be observed that the only time these tWo relays are released at the same time is when section AT is occupied. That is to say, the only time when these two aproach control relays are both released is under the condition that the track section between the two entering signals L6 and R8 is occupied.

As stated hereinbefore, a centralizd traino control or remote control system is associated with th stretch of track F for controlling the switches S and 'ES and the signals associated therewith. Such centralized traiiic control system may take dilerent forms and may be, for example, that, covered by Letters Patent of the United States No. 2,229,249, granted January 2l, 1941, to L. V. Lewis for Remote control systems. In the present application only that portion of the apparatus of such centralized trafc controlling system necessary for a complete understanding of my invention has been shown. An oiiice FS is connected to stations l--S and .Fiby a line circuit designated C. T. C. line circuit. Coding units which are indicated conventionally as CSO, CS? and CS-5 are provided at the oice FS and stations 1-8 and 5 6, respectively. As set forth fully in the aforementioned Lewis Patent No. 2,229,249, the operator at the oilce FS can through the medium of the coding units transmit a control code to either station 5--6 or lfor selectively energizing control relays which govern the positions of the track switch 5S or 'iS the case may be, or which govern the positions of the signals associated with these track switches. At station 5 5 only the control relays ERWP and LSSR are' shown since the other control relays located at 'this station are not involved in my present invention. Relay SRWP when picked up 1s eiective to cause operation of track switch 5S to its reverse position, that is, to the position for traic to move to and from siding Fa, operation oi the switch being accomplished by the usual power switch machine governed over a circuit controlled by relay SRWP. The point to be noted in connection with relay 5RWP asfar as the present application is concerned is the fact that front contacts i3 and 2! of that relay are in eluded in the circuit network for approach reiay RAR, so that relay 5RWP when picked up to cause switch 5S to be set for movement to the siding, by-passes the control circuit or" relay REAR around track relays STR and STR and approach relay RSAR is released only at such time that track section A5T is occupied. It is to he noted that in place of using contacts I8 and 2i ci switch control relay SRWP for by-passing the circuit of approach control relay RSAR around track relays 5TR and STR, contacts it and 2i may be contacts of the usual switch repeater relay governed by the position of switch 5S.

Control relay LiiSR at station 5-5 when picked up in response to a control code completes a circuil:l for a signal control relay LAl-I, such circuit including terminal B, front contact 3S ofrelay LSR. contact 39 operated by switch v5S and closed when the switch is set at its normal position, winding of relay LSAH, front contact 'iii voi track relay ETR and terminal C. Relay LtA-I- when picked up closing front contact M completes an obvious operating circuit for signal LAS to operate that signal 'to a proceed position. In accordance with my invention relay LSAH also controls directional stick relay LGS, the pickup circuit for relay LSS extending from terminal B over back contact i3 of track relay 5'IR, front contact d2 of relay LSAI-I, winding of relay LGS and to terminal C. Relay LBS when picked up closing its own front contact 4d completes a stick circuit path around contact 42 of the signal control relay LGAH. It is to be recalled that front contacts il and E@ oi relay LiiS are interposed in the circuit network of approach relay RSAR. The function of directional stick relay LBS will appear when the operation of the apparatus of Fig. 1 is described.

At station 'i-B only the switch control relay 'HRWP for governing oper-ation of switch IS to its reverse position, and the signal control relay RHSR for signal R3 are shown since the other control relays of this station are not involved in the present invention. Relay 'IRWP when picked up in response to a proper control code transmitted from the omce in addition to causing operation of switch 'ES to its reverse position through the medium of the usual switch machine not shown, also controls at its front contacts 32 and 35 by-pass circuits in the circuit network for approach relay LAR, as described hereinbefore. Again', it is to be noted that in place of using contacts 32 and 35 of switch control relay 'iRWP to by-pass the circuit of approach relay LSAR around contacts of track relay ETR and BTR, contacts 32 and 35 may be contacts of the usual switch repeater relay governed by the position of switch 1S. Relay RBSR is picked up in response to a control code transmitted from the oiiice and completes at its front contact l5 a circuit ior a signal control relay RSAH, such circuit also including contact 46 closed when switch '."S is set at its normal position and froritcontact 41 of track relay TTR. Signal control relay RSA1-I when picked up closing front contact 48, completes an obvious operating circuit for signal RA8 and this signal is operated to a proceed position. In accordance with my invention, signal control relay RBAH controls directional stick relay RBS, the pick-up circuit for relay RBS including terminal B, back Contact 49 of track relay llTR, front contact 5B of relay RSAH, winding of relay RSS and terminal C. Relay RBS when picked up to close its own front contact 5I, completes a stick circuit path around front contact 5!) of the relay RBAH. It is to be recalled that front contacts 3| and 313 of the directional stick relay R8S are interposed in the circuit network for the approach relay'LAR and the function of directional relay RSS will also appear when the operation of the apparatus of Fig. 1 is described.

At the office FS indication relays LEAK andv R8AK and an indication lamp 5E have to do with the present invention. The lamp 5E is preferably on a track model of the stretch F to indicate when illuminated occupancy of track section AST, that is, to indicate the presence of va train between the entering signals L and R8 of the adjacent sidings Fa and Fb. Indication relay LSAK is effectively energized and picked up by means of the centralized traliic control system in response to a preselected indication code transmitted from station 5 5, and Vwhich indication Icode is initiated when approach relay LGAR is released closing back contact 52 to apply positive volta-ge to a designated terminal of the coding unit CSS of station 5 6. Likewise, indication relay RBAK 'is effectively energized and picked up in response to a preselected indication code transmitted from station 1 8, and which indication code is initiated when Iapproach relay RBAR is released closing back contact 53 to apply positive voltage to a designated terminal of the coding unit CS1 of station 1 8. Relays LBAK and RSAK when picked up complete a circuit for lamp SE, such circuit including iront contact 54 of relay LSAK in series with `front contact 5S of relay RBAK as Will be apparent by an inspection of Fig. 1.

In describing the operation of the apparatus of Fig. 1 it is wto be noted that normally, that is, when the stretch of track F is unoccupied, the track relays are all picked up, and approach relays LSAR and RBAR are energized with the result that indication relays LSAK and RB'AK at the oice FS are released and vlamp 5E is dark. In the event signal RAE is operated to a proceed position to permit an eastbound train to move through the stretch of track F and such eastbound train enters section 6T, approach relay RSAR is released when track relay STR is shunted, and release of approach relay R8AR causes an indication code to be transmitted from station 5 3 which results in the indication relay RBAK at the office being energized and picked up. It is to be observed that approach relay RSAR in being released would also control the usual approach locking for signal R8. The eastbound train on advancing into detector section 5T shunts track relay STR to open additional points in the control circuit for approach relay RBAR. This eastbound train upon entering section AST to shunt track relay ASTR opens the Vcircuit. lfor approach relay RAR 4at additional points and also opens the circuit for approach relay LSAR associated with the westbound entering signal L6. The release of approach relay LSAR causes an indication code to be transmitted from station y5 5 which results in indication relay LSAK being picked up. Since beth indication relays RSAK and LSAK are now energized and picked up, the lamp SE is illuminated -to indicate that the section AST is Voccupied by this eastbound train. To advance this leastbound train beyond siding Fb, the operator transmits a control code for picking up the relay RSSB. at station 1 8 so that signal vcontrol relay RBAH is picked up and the signal RAS is operated to a proceed position. The eastbound train upon moving past signal R8 to enter section 1T shunts track relay 'ITR causing signal vcontrol relay RBAH to be deenergized and released and signal RA8 to be restored to its stop position. Signal control relay R8AH is slow releasing in character and Yhence when track relay HTR is shunted clos-ing its back contact 49 the pick-up circuit of directional stick relay RBS is closed during the slow release period of relay R-BAH, and relay RBS when thus picked up is retained picked up subsequent to the release of relay RSA1-I over its stick circu-it with the result that direction-al relay RBS remains picked up until such time as the eastbound train vacates track section 'IT and track relay TTR is picked up. Since for eastbound traffic, the westbound signal LAS is set at stop closing contacts 30 `and 33 and since directional vstick relay RSS is Picked up closing front contacts 3| 4and 34, the circuit network for approach relay LGAR is closed around the control ci track relays TTR and STR with the result that approach relay LSAR is revacates track section AST. The approach relay RBAR is also picked up when the train vacates track section AST unless a second or following eastbound train happens to be occupying the section 6T or the section ST. It is to be seen therefore that under normal movement of eastbound traiic both approach relays RBAR and LSAR are reenergized when the eastbound train vacates section AST and both indication relays RBAK and LSAK are released causing lamp SE to become dark. Furthermore, in the event a second eastbound train occupies section 6T causing approach relay R8AR to remain released and its corresponding indication relay RAK to remain energized, subsequent to the first eastbound train vacating section AST, the other approach relay LBAR is reenergized and picked up causing indication relay LSAK to be deenergized with the result that lamp SE becomes dark indicating that the track section AST between the two sidings is unoccupied. In other words, indication lamp SE when illuminated informs the operator that the track between the entering signals R8 and L5 is occupied.

The operation of the apparatus of' Fig. 1 for a westbound train is similar to that just described in connection with an eastbound train, and it is believed that the operation of the apparatus for westbound traino will be apparent from an inspection of Fig. l when considered in connection with the description of the operation of the apparatus for eastbound traflic.

It should be pointed out that the released position of directional relay RSS associated with eastbound traic is checked by the fact that its back contact '5S is interposed in the control of the westbound signals LAB and LCS, and that the released position of directional relay LBS associated With westbound traic is checked by its back contact 51 being interposed in the control of eastbound signals RAS and RCS.

Referring to Fig. 2, a stretch of single track Fl includes both ends of passing siding Fa, such siding being provided with track switches 5S and 3S. This stretch FI is formed into track sections AZT, 3T, AT, Aar, e'r, 5T and At'r; and each of which track sections is provided with a track circuit including a battery 2 connected across the rails at one end of the section and a track relay R plus a prex corresponding to the section connected across the rails at the other end of the section. Trac at switch 5S is governed by entering signal LB and leaving signals R6 and RCS, and at switch 3S by entering signal R4 and leaving signals L4 and L04. It is to be noted that there are three track sections 4T, A4T and 6T between leaving signals R6 and L4. These signals of Fig. 2, like the signals of Fig. 1, would be controlled in part by traic conditions of the associated stretch and in part by a centralized traiic control system. Of such control for the signals of Fig. 2, only that portion that has to do with the present application is shown. In Fig. 2 an approach relay RSAR associated with signal RS is normally energized by a circuit formed from terminal B over front contacts 58, S9, 6D, 6| and 62 of track relays AZTR, 3TR, 4TR., A4TR and STR, respectively, winding of relay RGAR, front contacts 63, E4, SS, 66 and 61 of track relays STR, A4TR, 4TR, STR and AZTR, respectively, and to terminal C. In the circuit for approach relay REAR contacts 68 and 69 closed when Signal R4 is set at stop, by-pass front contacts S8 and 61, respectively, of track energized and picked up as soon as the train 754 relay AZTR, and the front contacts lo and 1| of a switch control relay-3RWP to be referred to later, form a shunt path around the contacts of both track relays AZTR and 3TR.

An approach control relay LliAR for signal LA-l is provided with a normal circuit including and 85 of switch control relay SRWP form shunt paths around the contacts of both track relays STR and ASTR.

In the associated centralized traic control system, the cnice FS is connected to stations 6 and 3 6 over the C. T. C. line circuit, and coding units CSO, CSS and C53 of oflice FS and stations 5 5 and 3 4, respectively, are associated with such line circuit in the same manner as explained in connection with Fig. 1 and as fully explained in Patent No. 2,229,249, reierred to hereinbefo-re. At station 5 6, only the one control relay ERWP is shown since that is the only control relay involved in the apparatus oi Fig. 2 and this relay is effectively energized and picked up in response to a control code transmitted from the oiiice and relay 5RWP 'when picked up is effective to set in motion the i operation of moving switch 5S to its reverse position the same as in Fig. 1. The point to be noted inconnection with control relay SRWP in Fig. 2 is the fact that when this relay is picked up closing front contacts 84 and 85, `by-pass paths vare formed for the circuit of approach relay LLlAR around the contacts of track relays STR :and ABTR. At stations 3 4, only the one oontrol relay SRWP is shown Since this is the only control relay at that station involved in the present application. Relay BRWP is picked up in response to a proper control code transmitted from the office and whenpicked up it is effective to cause operation of switch 3S to its reverse position and to complete at its front contacts and 'il by-pass paths around the contacts of track relays ETR and A2TR for the circuit of approach control relay REAR. It should again be pointed out that in place of contacts of the switch control relays 3RWP and 5RWP being used in the networks of the associated approach relays, contacts of the usual switch repeater relays governed by the positions of switches 3S and 5S can be used in the networks since a switch repeater relay indirectly repeats the position of the switch control relay.

` At the oce an indication relay LAAK is energized in response to an indication code sent out from station 3 4 due to approach relay MAR lbe'ing released to close back contact 86 and applying positive voltage to a designated terminal of the coding unit CSS. Indication relay REAK at the ofdce is energized in response to an indication code sent from station 5 5 when approach relay RGAR is released to close back conoccupies detector section 5T, a directional stick the track relays are allpicked up and approach relays RSAR and LliAR are energized with the result that the indication relays LllAi and RGAK are released and the track indicator lamp iE is dark. In the event an eastbound train is to move through the stretch FI and enters the track section AZT in approach to signal R4 as well as in the approach to signal Re, the approach `relay RiiAR is deenergized and released, if signal Rfid is operated to a proceed position for an eastbound train, closing back contact 8l and causing an indication code to be transmitted which results in the indication relay RSAK being energized. When. the train passes signal RAli and enters track section 3T, track relay 'TR is shunted to open the control circuit for approach relay REAR at additional points and when the east- .bound train enters section 1T to shunt track relay dTR, the circuit for approach relay RcAR is opened at other additional points and the circuit for the approach relay LcAR is opened. Relay LliAR when released to close back contact et causes an indication code to be transmitted from station 3 6 which results in indication relay LAK being energized. Both indication relays LliAK and RiiAK at the oice being now picked up, the lamp 4E is illuminated to iniorm the operator that the section 14T is occupied the eastbound train. This condition is continued while the eastbound train traverses the track sections AIiT and 5T, since track relays AaTR and STR both control the circuits for both approach relays RbAR and LfiAR. lnmother Wordsthe indication lamp 4E is 4continuously illuminated while the eastbound train occupies the track sections between leaving signals Li and Re.

Assuming that signalRAt is operated to a proceed position to permit this eastbound train to enter section 5T, the control circuit for approach relay LliAR is held open at iront contacts i3 and .Sil of track relay STR While approach relay vREAR is reenergized and picked up when the train vacates the section ii' and approach relay REAR on being picked up causes indication relay RAK to be deenergized with the result that lamp 4E becomes dark to indicate that the train has vacated the vstretch between the signals Lil and R6. y

In the event it is desirable to Areenergize approach relay LQAR when this eastbound train inspection of Fig. 2 when considered in connection with the description of the operation of the apparatus for an eastbound train.

It is to be seen therefore that I have provided novel and improved means for indicating occupancy of a center portion between the two end portions of a stretch of track, .such as, for example, the intermediate track section between the two detector track sections of adjacent passing sidings, or the intermediate track section between the two detector track sections at the two ends of a passing siding, and repeater relays for the track sections of such stretches governed are not required.

'Although I have herein shown and described only two forms of railway traii'ic controlling apparatus embodying my invention, it is understood that various Vchanges and modications `may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

VHaving thus described my invention, what I claim is:

" 1. In combination, a stretch of single track railway including the adjacent track switches of two' adjacent sidings, said stretch arranged with ra detector track section at each of said switches and an intermediate track section between such detector sections, an entering signal for each siding located at the junction of the detector section of that siding and the intermediate section, a track circuit including a track relay for `control relays one for each of said signals, a

directional relay for each detector section and Velective when energized to by-pass the respective approach relay circuit around the track relay of the respective detector section, means governed by each signal control relay when picked up to energize the directional relay for the detector section at which the associated signal is located, two indication relays one for each approach relay and each such indication relay energized by said remote control system when vtheV respective approach relay is released, and a track .indicator controlled over a circuit including in series a front contact of each of said indication relays to indicate when a train occupies said intermediate section only.

-2.` In combination, a stretch of single track railway including two adjacent sidings and arranged with an intermediate track section be- -tween the two detector track sections for the adjacent switches of the sidings, a track circuit including a track relay for each of said track sections, two entering signals one for each siding, an approach relay for each such signals, a control circuit for each approach relay and including a contact of the track relay for the detector section at the switch remote from the respective signal and a contact of the track relay of the intermediate section, a remote control system associated with said stretch and including two signal control relays one for each of said signals, two. directional relays one associated with each said signal control relay and energized over a 4pick-up circuit including a front contact of the vrespective signal control relay and a back contactof the track relay for the detector section adjacent the signal governed by that signal control relay, a by-pass circuit for each of the approach relay control circuits to by-pass the circuit around the front contact of-the respective `detector section track relay and including a front over line circuits requiring additional line wires contact of the directional relay for the signal control relay of the signal governing traffic over that detector section, two indication relays one for each of said approach relays and each said indication relay energized by said' remote control system when the respectiveapproach relay is released, and a track indicator controlled over a circuit including in series a front contact of each of said indication relays.

3. In combination, a stretch of single track formed with two spaced detector track sections each of which includes a track switch and which sections are separated by at least one intermediate track section, a track circuit including a track relay for each of said sections, a signal at each detector circuit to govern traffic over the respective track switch away from said intermediate section, an approach relay for each of said signals controlled through a circuit including a front contact of the track relay of each intermediate section and a front contact of the track relay of the detector section remote from the respective signal, a remote control system having an olce from which said signals and switches are governed, means governed by said remote control system to by-pass each approach relay circuit around the front contact of the respective detector section track relay according to the control established for the switch and signals associated with that detector section, two indication relays at said ofce one for each of said approach relays. means governed by each approach relay to energize the respective indication relay through said remote control system when the respective approach relay'is released,

and a track indicator controlled by a circuit in- `said signals, each of said approach relays controlled by a circuit includingV a front contact of the track relay for said intermediate section and 'a front contact of the track relay for the detector section remote from the respective signal, a remote control system including a remote office for said stretchfor governing the switches and signals associated with said siding and said system provided with a switch control relay for each said switch, means governed by `each of said switch control relays to at times by-pass the -approach relay circuit around the front contact ofthe detector track circuit at the respective switch, two indication relays at said office one foreach of said approach relays, means governed -by each of said approach relays to energize the 4respective indication relay through said remote control system, and an office track indicator Ycontrolled by a circuit including in series a front contact of each of said indication relays.

JAMES J. VANHORN.

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