US1936313A

US1936313A - Signal system for railways

Info

Publication number: US1936313A
Application number: US556983A
Authority: US
Inventors: Paul P Stoker
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1931-08-14
Filing date: 1931-08-14
Publication date: 1933-11-21
Anticipated expiration: 1950-11-21

Description

NOV. 21, p P STOKER SIGNAL SYSTEM FOR RAILWAYS Filed Aug. 14, 1931 2 Sheets-Sheet l L2 BZT 42 F1016! Szoraqe 0/717.

FLEWS 46 [Wale/Line l/nl'.

' INVENTOR:

P P 5t aka I" 1 Y g ATTORNEY.

NOV. 21, 1933. P. p STOKER 1,936,313

SIGNAL SYSTEM FOR RAILwAYs Filed Aug. 14 1931 2 Sheets-Sheet 2 Field BLI Field Szorage Z 021?.

mpzc/ um Z/m'f. i j

INVENTOR.

P P. stoke/ RmQLMZ NM A TTORNE Y.

Patented Nov. 21 1933 omrso STATES PATENT QFFIE The Union "Switch &

Signal Company, Swissvale, Pa, a corporation of Pennsylvania App a u ust 1 16 Claims.

My invention relates to signal systems for railways, and particularly to signal systems for single track railways whereon trailic is controlled from a central office.

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

The accompanying Figs. 1 and 2 when taken togeiher with Fig. 1 on the left constitute one form of my invention when applied to a stretch of single track extending between two passing sidings designated by the reference characters PS and PS1. In describing my invention I shall speak of the righthand end of each figure as east and the left-hand end as west, and I shall speak of a train travelling from the left to the right as an eastbound train and one travelling from the right to the left as a westbound train.

The

traffic rails

1 and 2 of the stretch of railway are divided into track sections by the customary insulated rail joints 3. Starting from the left these track sections are designated by the reference characters 4T, A4T, 2T, A2T, 132T, C21, DZT, E2T and 4T.

Although it was stated above that Figs. land 2 when taken together with Fig. 1 on the left dis closes a form of my invention applied to a stretch of railway between two passing sidings, I shall at certain places in the description consider Fig. 1' to be placed at the right of Fig. 2 so that the track section 4T of Fig. 1 mates with the track section lT of Fig. 2. When Fig. 1 is thus placed at the right of Fig. 2 there is disclosed a form of the apparatus of my invention as applied to signals at the two opposite ends of a passing siding. 3

While in Figs. 1 and 2 a specific arrangement of track sections is disclosed it will be understood that my invention is by no means limited to this one arrangement but that the traffic rails may be divided into track sections as best suited to the local conditions. 7

Each track section is equipped with a track circuit here shown as the conventional direct current wherein a battery 4 is connected to the rails at one end of the section and a direct current neutral relay is connected across the rails the opposite end of the section.

wayside signals R2 and R4 govern eastbound trafiic while the signals L4.and L2 govern wesbound traiiic. These wayside signals may be a clear indication or a stop indication, while the 1931. Serial No. 556,983

lower signal B of R2 and L4 is a permissive signal capable of displaying either a permissive indication or a stop indication. The entrance signals L2 and R4 are each three position signals capable of displaying clear, caution or stop. H1 and H3 are .take siding. signals and when displayed convey to the approaching train the information that that train is to enter the siding. These take'siding signals may take different forms such for example as a short semaphore arm, or disk or a distincive light and. as here disclosed each is to be a distinctive light. .While no intermediate wayside signals are shown in Figs. 1 and 2 such signals may be used if it seems desirable to do These wayside signals are to be jointly controlled by means of a remote control system and by track circuits responsive to traffic conditions of the track sections. The remote control system may be one of many schemes now in use; however, a preferred system to which my invention is particularly adapted is that disclosed and claimed in the United States application of Snavely, Miller and Tuneli for Remote control systems, Serial No. 538,380, filed May 18, 1931.

The above remote control system constitutes a means by which signal systems can be manually controlled and operated from a remote or centralized location. 1 This remote control system carries out its remote control by codes designed on the circuit sequence principle. The codes are given individual character by the sequence in which the control circuits are operated. A line chanhel consisting of three wires connects serially from the central office equipment through each field station equipment. This three wire channel provides two independently operated series circuits and'one common return circuit. Since two independent series circuits are provided the line r action at any instant may be given any one of 0 three characters dependent upon whether the first circuit, the second circuit or both circuits are operating. These three variables have been designated respectively as X, Y and Z. Each code action, either control or indication; consists of eight successive steps. Each step has a specific function and is identified by one ,of the three char acters X, Y or Z. In the disclosure of this application only enough of the field apparatus of the remote control system is shown to clearly illustrate a preferred manner whereby the apparatus of ,my invention may be governed by an operator located at acentral office, and also to illustrate themanner whereby the wayside signals may be made to govern a return indication to the central oiiice.

In Figs. 1 and 2 the relays shown within the panels indicated by dash and dot lines are relays of the field line unit, the field storage unit and the field coding unit, respectively of the abovementioned remote control system, and each of these relays is here given the same reference character that identifies the corresponding relay in the above-mentioned application Serial No.

538,380. For this description,itis deemedsuiiicient to say that the remote control system permits the operator at the central ofiice to select, by sending the proper code, either one of the controlling relays BXS or GYS, and either one of the relays 'YXS or 'TYS of the storage unit at any one of the field stations along the railway. Also, that when one of these relays is selected it becomes energized to raise its armature into engagement with front contacts and that when once energized by a control code it is held energized by a stick circuit until its function is fully completed or until a new control code is transmitted by the operator. It is to be pointed out that while the relays GXS and SYS are ordinarily utilized to govern the operation of a local switch machine, I propose in this system to utilize these relays GXS and SYS at each location to control the take siding signal and the permissive signal as will be fully described later.

Relay SA of the field storage unit is the starting relay for the return indication, while relays 6V and 7V govern the energization of relay SA. Relays T6 and T7 are the sixth and seventh step chain group relays, respectively, while relays TX, TY and T2 of the field line unit are the transmitting relays for supplying to the line channel to the central ofice an X, Y or Z character. As the manner whereby these several relays of the remote control system function in connection with the apparatus associated with the return indication of the remote control system forms no part of my invention, the full operating circuits for the relays are omitted from the figures for the sake of clearness. It is deemed sufiicient for this specification to point out that the indication code action is made up of eight successive steps and is started by the energizing of the relay SA of a field storage unit. Each step of an indication code action'is distinguished by one of the three characters X, Y or Z, so that the indication code action at the central office is determined by the successive characters of the eight steps. Individual starting circuits for each signal function are arranged so that they become energized only on a change of status of the wayside signal equipment. Energy is cut off the starting circuit by a relay V of the field storage unit at the completion of the indication code action by the controlling relay V being energized or deenergized as the case may be to set up a disagreement between the relay SA and the wayside signal function. The character of the successive steps of an indication code is obtained by energizing one of the transmitting relays TX, TY or T2 of the fieldline unit. The manner whereby the wayside signal apparatus of my invention controls the starting circuits for the starting relay SA and controls the current for energizing the transmitting relays TX, TY and TZ will be fully described as the specification progresses.

Energy at each switch location D and E is obtained from a line transformer L the primary 5 of which is permanently connected to a transmission line designated by the

line wires

6 and 7 which are constantly supplied with alternating current of any convenient frequency, such as 60 cycles per second, from a source not shown in the figures. The secondary 8 of the transformer L is connected to the terminals of a storage battery 9 through a full wave rectifier 10, and thus it follows that the storage battery 9 is trickle charged by current from the transmission line.

The storage battery 9 supplies direct current at the proper voltage to the several operating and control circuits. The positive terminal of the battery 9 is designated in the figures by the reference character BL while the negative terminal is designated by the reference character CL.

The operating circuits for the entrance signals L2 and R4 are governed by direct current polarized relays L2H and RAH, respectively. LZHP and RAHP are slow releasing repeater relays as sociated with the polarized relays L2H and R lZ-I respectively, and each is energized by a simple circuit that includes a front contact of the associated polarized relay as will be readily understood by an inspection of Figs. 1 and 2.

As the operating circuits of signals L2 and PA are alike, a description of the circuits for one will sufiice for an understanding of both. Referring to signal L2, its clear operating circuit starts from. the positive terminal BL of the bat tery 9 and includes the front contact of the armature 11 of the repeater relay L2l-IP when it energized in response to the energization of the relay L2H, front contact of the armature 12 of the polarized relay L2H when'that relay is ene gized in a manner to be described later, righthand contact of the polarized armature 13, wire 14, signal L2 and to the negative terminal CL. The caution operating circuit is the same as that just traced for the clear circuit up to the polarized armature 13, thence by the left hand contact and wire 15 to the signal L2 and to the negative terminal CL. The stop operating circuit includes the back contact of the armature 11 of the repeater relay L2HP and wire 16 to the signal L2 and to the negative battery terminal CL.

The polarized relay L2H is controlled by means 18, back contact of armature 19 of a despatcher controlled relay RAHS, wire 20, front contact of armature 21 of the track relay iTR for the track section 4T, line wire 22, front contact of armature 23 of the track relay AlTR, front contact of armature 24 of a despatcher controlled relay when that relay is energized in a manner to be later pointed out, winding of the relay L2H, wire 25, back contact of armature 26 of a despatcher controlled relay'lHS, front contact of armature 2'7 of relay L2HS, front contact of armature relay LA4H and to the negative battery terminal 1U;

CL. It will be observed that when the signal con-- trolling relay LA4H for the signal in advance is energized so as to bring its armatures l7 and 34 into engagement with front contacts, the

polarity of the current supplied to the above in:

energized to clear the signal traced-line circuit is reversed. Thus, the polarized signal controlling relay L2H for the signal L2 is energized when the despatcher controlled relay LZHS is selected and thetrack sections between the signal L2 and the next signal in advance are unoccuplied. The current supplied is of one polarity when the relay controlling the next signal in advance is energized to clear that signal and is of the reverse polarity when the relay for the signal in advance is deenergized.

In like manner the polarized relay R4H'for the signal R4 is controlled by a polarized line circuit that receives current at the head clock signal located at the opposite end of the siding. Still considerirr Fig. 2 to be placed at the left of Fig. l, the circuit for the relay R411 can be traced from the positive terminal BL through the back contact of armature 35 oi the signal controlling associated with the signal R2, wire 36, back contact of armature 37, of the despatcher controlled relay LZl-IS, wire 38, front contact of armatifc 39 of the track relay line circuit 40, front contact of armature l of the track relay 4TB, front contact of arn1ature 42 of the despatcher controlled relay PAHS when that relay energized, back contact of armature 43 or" the relay SEIS, winding of relay P.4d. front contact of armature 19 of the relay 8, wire 26, front contact of armature 21 of the relay 41, line Wire 22, front contact of armature 23 of the relay -TP 6, back contact of armature 24 of the relay LZES, wire 44, back contact of armature 45 of the relay RA2H and to the negative terminal CL. Thus, the circuit for the signal controlling relay R4H is closed when the depatcher selects the relay R4HS and the tracl: sections between the signal R4 and the next signal in advance are unoccupied. The current is of one polarity when relay RA2H is R2 and is of a rev rse polarity when the relay RAZH is down and the signal R2 is at stop.

The circuit for the despatcher controlled relay LZHS that governs the signal controlling L2H is cl sed when the clespatcher selects the relay 'ZXS of the field storage unit at the switch location D to thereby bring armature 47 into engagement with its front contact. This circuit for enei log the relay L2l-lS starts at the positive terminal 13L at the armature 46 of the relay NS and includes the back contact of armature front contact of armature 47 of relay back contact of armature 43 of the relay wire 49, winding of the relay L2l-IS and to the negative terminal of the battery 9. A similar circuit is provided for the despatcher controlled relay B41 55, which is closed when the despatcher selects the relay 7Y8 of the field storage unit at the switch location E to thereby .5 its armature 52 into en agement with a front cntact. Likewise the despatcher controlled relays R2E-IS and L4HS govern the signal rolling relays RA H and L4HS, respectively. The circuit for the relay R258 is closed at the front contact of armature 50 of the relay 'YYS at J. e location D, while the circuit for the relay L4l-1S is closed at the front contact of armature 51 of relay 'ZXS at the location B.

The absolute signal A of the head block signal L4 is governed by signal controlling relay LA4H, while the permissive signal B is governed bythe relay In similar manner the absolute signal A. of the head block signal R2 is governedby the signal con rolling relay RA2l-l and its pere missive signal B is governed by the relay RBZH.

With Fig. I placed on the left of Fig. 2 so that signals L4 and R2 are opposing head block signals governing trafiic in opposite directions through the stretch of track between the sidings PS and PS1, the relays RAZH and LA4H, which govern the opposing absolute signals RA2 and LA4, respectively,are controlled by a line circuit that is normally connected to battery at each end of the stretch. Starting at the switch D this line circuit can be traced from the positive battery terminal BL through the back contact of armature 53 of a stick relay RZS to be referred to later, back. contact of armature 54 of the relay RZI-IS, wire 55, front contact of armature 56 of the track relay ZTR, line wire 5'7, front contacts of

armatures

58 and 59 of the track relays AZTR and BZTR, respectively, line wire 60, front contacts of

armatures

61 and 62 of the relays CZTR and D2TPJ, respectively, line wire 63, front contact of armature 64 of relay EZTR, wire 65, back contact of armature 66 of relay L iEl'S, and back contact of armature 67 of a stick relay L48 to the positive terminal BL at the switch location E. The other side of the line circuit is normally connected to the negative terminal CL at the switch location D from which it extends through the back contact of armature 68 of the relay RZHS and then through the following elements in

succession

69, 70, 71, '72, 73, 74, '75, '76, 77, 78, 73', the back contact of armature 80. of the relay L435 to the negative battery terminal CL at the switch location E. It follows, therefore, that normally this line circuit is deenergized. With the despatcher transmitting a control code that energized the relay 'ZYS at the switch location D the relay RZI-IS is energized turn to bring its armatures 54 and 68 into engagement with front contacts and out of engagement with their back.

contacts with the result that the above traced line circuit is disconnected from the battery at location D and is connected to the terminals of the signal governing relay RAZH by

wires

115 and 116. Under this condition the relay BAZH is energized by current now supplied to the line circuit by the battery at the switch location E in the event the intervening track sections are unoccupied and each track relay picked up. With the relay RA2l-l thus energized the clear operating circuit to the absolute signal RA2 is closed at the front contact of the armat re 81.

selects the relay 'YXS at the switch location so that the despatcher controlled relay L4HS is picked up to thereby bring its armatures 66 and 89 into engagement with their front contacts and out of engagement with their back contacts, then the above-traced line circuit is disconnected from battery at the location E and the signal controlline relay LA4H is connected thereto. This results in relay LA4H being energized by current supplied to the line circuit at the location D if the intervening track sections are unoccupied. With relay LA4H energized the clear operating circuit to the absolute signal A of L4 is closed at the front contact of the armature 82. It follows .1

from the above discussion of the line circuit that only one of the opposing signal controlling relays LA4H and RAZl-l can beenergized at a time and that the control line circuit is controlled by a despatcher controlled relay and by the track rei lay of each track section between the two opposing signals.

Associated with the relays RAZH and LA4I-I are the stick relays R28 and L48, respectively. Referring to the relay RZS, we find that it ispro- In the event the despatcher sends a control code that the opening V of the storage unit, hack contact 0 vided with an energizing'circuit that starts at the positive battery terminal BL and includes a back contact of armature 83 of the track relay 2TB, front contact of armature 84 or" the signal controlling relay RA2H when that relay is energized, winding of relay R28 and to the negative battery terminal CL. The stick circuit for the relay 32S starts from the positive batter terminal BL and includes the front contact of armature 85 of the despatcher controlled relay REES, back contact of armature 38 of relay RA2H, front contact of its own armature 8'7, winding of the relay R28 and to the nega ive battery terminal CL. Thus, with a train entering the track section ET and shunting the track relay 2TB at a time when the signal controlling relay RAZH energized the stick relay RES is picked up and then held up inasmuch as the front contact of armature as of relay is retained closed for a time interval after track relay 2TB is shu' d due to the slow releasing character wi h ich relay RAH-1 is provided, and due to relay Rue ng made slightly slow acting so as not to release cont-acts between front contact as and the closing of back contact 86 of relay as that relay releases. As the circuits for the sti relay L-lS are similar to those for the relay it see-.. unnecessary to describe them in detail.

The permissive signal '3 oi" R2 its operating circuits governed by the armature 8 of the relay in s eh a manner that when the relay is energized and armature 88 brought into engag ment wit its front contact the permissive rial is display-ed while when the relay is dcenergized and the armature 88 engages its back contact the stop signal is displayed. In a like manner the operating circuits to the signal B of L l are controlled by the armature 89 of the signal controlling relay LBdH.

Although the sw ches D and as well as all switches of my system, are preferably hand-thr wn, at each switch, however, there is provided a signal by means of which the despatcher caniss .e instructions rise the usual and 6Y5 o? the field the remote control syst trolling the operation or the and to control the operation of i issive signal located at the same point. iders stood that when the despatchei desires to clear one or" the controlled by e relays 6};

and 61 s he does so by transl g a control code in the usual mar ne F0; on pie, a despatcher desired to take siding signal H1 displayed he would -J a control code that selects the relay 5"8 at location D. ll hen relay SYS picks up the circuit to the relay li-IS is closed at the front contact f the armature 92, and when relay 1H3 i up the operating circuit to the sign l H1 closed at'the front contact of the armature 93. As the relay GYS is selected by the control code nitted from red for that relay which extends from the no ye terminal BL through a circuit controller 1' operated by the switch I) and opened wh n the switch is thrown for traiiic to the :2 ng, wire its, resist ance 107, contact C1 operated by the apparatus nature 108 of the relay 6X8, front contact of 'mature 199 of relay 6YS, winding of relay 6Y8 and to the negative terminal CL through the usual control storage unit.

circuit of the storage unit. It follows then that as the train crew operates the switch D after having been instructed to take the siding by the display of the signal H1, the relay GYS is deenergized and the signal H1 immediately returned to its non-active position, it being understood that the energizing circuit for relay 6Y8 through the apparatus of the remote control system was opened at the completion of the control code. At the switch E the take siding signal H3 is controlled by the relay GYS of the storage unit at that location in a like manner.

In the event the despatcher at the central oiiice desires to permit a second eastbound train to follow a first eastbound train from the location D, he would do so by sending a control code that selects the relay 6X8 at location D, it being understood that the relay RZHS is now energized as the result of the control code that cleared the signal HA2 for the first train and that the stick relay RES is held energized by its stick circuit. When relay 6X8 is selected a circuit is closed from the positive battery terminal BL-through the back contact of armature lu l oi": the relay BYS, front contact of armature 90 of relay 6X8, front contact of armature 91 of the stick relay R25, winding of the relay RBZH and to the negative terminal CL. The energization of the relay RBZH effects the closing of the operating circuit for clearing the permissive signal B of E2. The permissive signal B of L4 controls following train movements west from the siding PS and is itself controlled by the relay 6X5; of the storage unit at the location E in a manner similar to that described for the signal B of R2.

previously mentioned, the remote control system provides a return indication from the wayside apparatus to the central oiiice indicating that the function desired has been completed by the wayside equipment. In the system as disclosed in the above-mentioned application, Serial No. 538,380 the indication code action accon plished in eight steps, and previously stated, each step consists of an X, Y or Z character. These X, Y and 2 characters are transmitted to theline channel by means of the relays TY and T2. of the field line unit at each field station. The starting of the indication code is controlled by means of the starting relay of the field In Figs. 1 and 2, I have shown a preferred manner whereby the wayside equipment of my invention may control the operation of these relays associated with the indication code of the above-mentioned remote control system.

Current for energizing the tarting relay SA o-fthe field storage unit may be e by any one of several parallel starting 0 its which are governed by the con ition 02' the wayside signal equipment and which are energized upon a change of status of the s.gnal equipment. Referring to Fig. i, when tlierelay L2H? is picked up to clear the L2, a starting circuit is closed from positive battery terminal BL through the front contact of armature 94 of relay LZHP, wire 95, and a front contact C3 of the relay 7V of the storage unit to starting relay SA. When the relay HAZE is picked up to clear the signal RAZ, a starting circuit closed from positive battery terminal BL through the back contact of the armature 94 of relay LZHP wire 96, from contact of armature 9'7 of relay RAZH and the front contact C3 of the relay 7V to the starting relay SA. When both relays L2I-IP andRAZI-I are down indicating that both signals L2 and R2 are set at stop, a starting circuit is closed from positive terminal BL through the back contact of the armature 94, wire 96, back contact of the armature 97 and the back contact C3 of the relay 7V to the starting relay SA; If relay RB2H be energized to clear the permissive signal R132 a starting circuit is closed from positive terminal BL through the fror. contact of the armature 110,

wires

111 and 99 and the front contact C3 of a relay 6V to the starting relay SA. In the event the relay ll-IS is energized to select the take siding signal H1, a starting circuit is closed from the positive terminal of the battery 9 through the front contact of armature 98 of relay IHS, wire 99 and the front contact C3 of relay 6V to the starting relay SA. Again, when the relay IE8 is deenergized to open the operating circuit to a signal H1, a starting circuit is closed from the positive terminal of the battery line through the back contact of armature 9S and the back contact 03 of the relay 6V to the starting relay SA. It is to be seen, therefore, that when a signal controlling relay takes a position to either clear a signal or to set a signal at stop a starting circuit is established to the starting relay SA of the remote control system.

The individual X, Y and Z characters of the sixth and seventh step of the indication code are selected by the various signal relays of my system in the following manner: When the chain group relay T6 of the field coding unit is picked up during the sixth step of the indication code action, current is supplied from the positive battery terminal BL through the front contact A5 of relay T6 to the armature 112 of relay RBZH and thence through the front contact of that armature if relay RB2H has been energized to clear signal BB2, and wire 113 to the winding of the transmitting relay TX of the field line unit to thereby transmit an X code character. If relay RBZH is deenergized then a circuit extends through the back contact of armature 112 along wire 114 to the armature 100 of relay 15S and thence through its front contact if relay 1H5, is energized to clear signal Hi, to the winding of the transmitting relay TY to transmit a Y character. In the event both relays RBZH and lHS are deenergized the circuit is completed from the armature 100 through its back contact to the winding of the transmitting relay T2 to thereby transmit a Z character.

During the seventh step of the indication code action when the chain relay T7 is energized a circuit is closed from the positive battery terminal BL through the front contact A5 of relay T7 to the armature 101 of the relay L2I-IP, thence through the front contact of that armature if relay LZHP is energized to clear the signal L2 to the winding of the transmitting relay TX to thereby transmit an X character during the seventh step of the indication code. With relay LZHP down, the armature 101 engages its back contact and the above circuit from A5 of relay T7 extends by wire 102 to the armature 103 of the relay RA2l-I, thence by the front contact of that armature if relay RA2H is energized to clear the signal HA2 to the transmitting relay TY to transmit a Y character during the seventh step of the indication code. In the event the relay RA2l-I is deenergized and the armature 103 is in engagement with its back contact the circuit is completed to the transmitting relay TZ to transmit a Z character during the seventh step of the indication code. Thus, not only are the starting circuits to the starting relay SA governed by the different signal controlling relays but the signal controlling relays also govern the circuits for energizing the different transmitting relays to determine the code character to be transmitted to the central oiiice during the sixth and seventh steps of the indication code action.

In describing the operation of my system I shall assume that an eastbound train occupies the track section A41 and that the remaining track sections are all unoccupied. In order to clear the signal RA2 so as to advance this eastbound train the despatcher transmits a control code that selects the relay 'YYS at the location D and as this 'relay is energized the relay RZI-IS is in turn energized. When the relay RZHS picks up, the line control circuit is disconnected from battery at the location D and the signal controlling relay RA2I-I is connected thereto so that that relay is now governed by current supplied to theline control circuit at the switch location E. As the signal controlling relay RAZH becomes energized the clear operating circuit for the signal HA2 is closed at the front contact of the armature 81. Also, a starting circuit to the starting relay SA is closed at the front contact of the armature 9'7, and during the seventh step of the return indication code the circuit to the transmitting relay TY is completed at the front contact of the armature 103. As the train advances east past the clear signal RA2 it shunts the track relay 2TB to open the control line circuit at armatures 56 and of the track relay 2TB to thereby deenergize the signal controlling relay RAZI-I to set the signal HA2 at stop. As the track relay 2TB is shunted, the energizing circuit to the stick relay R2S is closed during the release period of the relay RAZH and once the stick relay RZS is picked up, it is held energized by its stick circuit until the relay RZHS is deenergized by a control code or until the relay RA2H is again picked up due to the train passing beyond the limits of the track sections controlling the line control circuit. In the event a second eastbound train desires to follow the first eastbound train leaving the siding PS1 the despatcher transmits a control code that selects the relay 6XS at the switch location D to close the circuit that includes the front contacts of the

armatures

90 ,and 91 of relays 6XS and R2S,respectively, to

thereby energize relay RB2H. As the relay RBZI-I becomes energized the operating circuit is closed for clearing the permissive signal BB2 to thereby permit the second eastbound train to follow the first train without waiting for the first train to clear the track sections up to siding PS.

If any of the track sections between the two passing sidings is occupied by a westbound train, it is apparent that the relay RAZI-I will not be energized even should the despatcher select the relay RZHS by sending a code that selects the relay 'IYS at location D. Furthermore, the despatcher cannot select the permissive signal BB2 for an eastbound train if there is a westbound train occupying any of the track sections due to the fact that the stick relay R28 is deenergized in thiscase and the circuit to the relay RB2I-I held open at the front contact of the armature 91.

Let us now assume that a westbound train has been advanced west from thesiding PS by the despatcher clearing the signal LAe in a manner similar to that described in connection with the signal R2. If the despatcher desires toa'dvance the westbound train past the signal'L2 on the main track he transmits a control code that selects the relay 'ZXS at the location D to thereby energize the relay LZHS. As relay LZHS picks up the signal controlling relay L2H is connected to the line control circuit extending west from the location D. If the intervening track sections to the west end of siding PS1 are unoccupied the relay L2H becomes energized and its polarized armature 13 takes the right-hand position to close the clear operating circuit to signal L2 if the signal controlling relay for the westboundsignal at the west end of the siding PS1 is energized and the current supplied to the line control circuit of normal polarity. In the event the signal controlling relay at the west end of the siding PS1 is deenergized and its signal is at stop then the polarity of the current supplied to the control line circuit leading to the relay L2H is such that polarized armature 13 assumes a left-hand position to close the caution operating circuit of signal L2. As relay L2H becomes energized, a circuit is completed to the repeater relay LZHP and that relay is energized and the connection from positive battery terminal to the operating circuits for signal L2 is closed. The energization of the relay LZHP also completes a starting circuit to the starting relay SA at the front contact of its armature 94, and closes the circuit leading to the transmitting relay TX at front contact of its armature 101.

Should the operator desire the westbound train to enter the siding PS1, he transmits a control code that selects relay 6Y8 at the location D so that the relay IE8 is energized to close the operating circuit to the take siding signal H1. As relay 1H3 picks up, a starting circuit to the starting relay SA is closed at the front contact of its armature 98, and the circuit to the transmitting relay TY is closed at the front contact of its armature 100. The control and operation of the signals L4 and R4 are similar in every respect to those described for the signals R2 and L2.

A signal system such as here disclosed gives absolute protection for opposing traffic move ments, allows for following movements and proe vides a convenient means for instructing trains to take a siding at meeting points. This signal system requires but two control line wires between siding locations and three line: wires between opposite ends of sidings and is much simpler and less expensive to install than systems of this character heretofore'proposed.

Although I have shown my invention applied to a specific remote control system it will be understood that it can be as well applied toother remote control systems such for example as the time code type. 1

Although I have herein shownand described only one form of apparatus embodying my invention, 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: I

1. In combination, a stretch of railway over which traflic normally moves in either direction,

an absolute signal and a permissive signal located at each end of the stretch to control traflic in opposite directions through the stretch, a line control circuit, a signal controlling relay at each end or the stretch controlled by said line circuit to control the absolute signal at its end of the stretch but normally disconnected, despatcher controlled means to at times connect one or the other of said signal controlling relays to said line circuittoclear an absolute signal, a directional relay at each end of the stretch energized in re sponse to a train entering the stretch at the same end as the directional relay at a time when the associated signal controlling relay is energized, and other despatcher controlled means to clear a permissive signal when the directional relay is energized.

2. In combination, a stretch of railway over which traffic normally moves in either direction arranged in track sections, a track circuit for each track section responsive to trafiic conditions of the section, an absolute signal and a permissive signal located ateach end of the stretch to con trol traff c in opposite directions through the stretch,,a line control circuit controlled by the track circuit of each section, a signal c-ntrolling relay for each absolute signal controlled by said line circuit but normally disconnected, despatcher controlled means to at times connect one or the other of said signal controlling relays to said line circuit to clear an absolute signal, a directional relay at each end of the stretch energized in response toa train entering, the stretch at its respective end of the stretch at a time when the associated signal controlling relay is energized, and other despatcher controlled means to clear a permissive signal when the directional relay is energized.

3. In combination, a stretch of railway over which traffic normally moves in either direction arranged in track sections, a track circuit for each track section responsive to tranic conditions 1 of the section, a line circuit controlled by the track circuit of each track section and normally connected to a current source at each end of the stretch, a signal controlling relay at each end of the stretch controlled by said line circuit but nor- 1 mally disconnected, despatcher controlled means to disconnect at times the current source at either end of the stretch and to connect the signal controlling relay located at the same end as the disconnected source to the line circuit to thereby 1 energize said relay under clear traffic conditions of the track sections, an absolute signal at each end of the stretch cleared when the corresponding signal controlling relay is energized, a stick relay associated with each signal controlling relay 1 energized in response to a train entering the track section adjacent its end of the stretch at a time when the associated signal controlling relay is energized, a permissive signal at each end of the stretch, and another despatcher controlled 1 means effective to clear the permissive signal located at the end at which the stick relay is energized.

4. In combination, a railway having a main track and a passing siding, a track circuit for the main track, a signal to govern trafiic over the main track, a take siding signal to instruct a train approaching said siding, a first despatcher controlled relay, a first signal controlling relay to control the signal for the main track jointly controlled by the track circuit and the first despatcher controlled relay, a second despatcher controlled relay, a second signal controlling relay controlled by the said second vdespatcher con-- trolled relay to control the take siding circuit means rendered active when the first signal controllingcrelay functions to clear its associated signal to initiate areturn indication, and another circuit means rendered active when the second signal controlling relay functions to clear 1 1 signal, a

the take siding signal to also initiate a return ina railway having a main nal to govern traffic over the turn is rendered active when either connected a track switch to a 11 rack a a passing siding ad- 0, a al to govern the moveoin the single track to the main ignal to govern the movement y controlled by the first desrelay to clear the main signal T1 to enter the in in track, a secr controlled relay, a second signal cont d relay to set the take siding signal to instruct train to enter the siding, and means to preve t the first des'oatcher controlled the operation of the signal saiu stretch, a neutral relay ation of the signal at the east despatcher controlled relay at he west the stretch to control the ener izer e polarised relay, and a despatcher con -oJ- u relay at the east end of the stretch to control the energization of the neutral relay and to control if e polarity of the current energizing the pol iced relay at the west end of the s retch.

end of L v su system for railways over which rally moves in either direction includ- "n opposite directions through the e circuit for s ..d stretch adapted to irection of trafiic, despatcher to select the direction for which olute signal arranged to be conine circuit when it is rendered active for the same direction of traffic as that govtrolled by t 1 erned by t each oe trolled lays l: der the effective to one signal gove 'ng traffic in the same direction as that with l. first mentioned despatcher controlled nieans has rendered the line circuit active. 7

associated absolute signal, a relay for 1a1, other despatcher conenergiae the last-mentioned ally ineffective, and m ans to renissive 9.. A signal system for railways over which traffic normally moves in either direction and arranged in track sections including a track circuit for each track section responsive to traffic conditions oi the section, an absolute signal and a permissive cal at each end of a stretch of railway to govern traillc in opposite. direction through the stretch, a line circuit for stretch adapt-ed to b" active for either irection of tr:

espatcher controlled means to select the di. ection for which said'line circuit is to be active, a relay associated with each absolute signal arranged to be controlled by the line circuit when it is rendered active for the sarne'direction as that governed by the associated absolute signal, arelay for each 1? iseive signal,.etl1er despatcher controlled n ea s to e er ize t e last-mentioned relays but norr ally eiiective, means to render the said other esp'atcher controlled means effective to energize the relay for tie permissive signal governing traffic in the same direction as that with which the t mentioned despatcher controlled meanshas rendered the line circuit active, and means controlled by the traclr circuits of the sections for s fetch to control the line cuit when it is renccred active for either direction i traific.

i 10. A signal system for railways including a strelch of track arranged in track sections, a tracl: circuit for each track section responsive to traffic conditions of the section, an absolute signal and a permissive to govern traiiic through the stretch, a line circuit, a signal controlling relay, a first despatcher controlled relay torender he line circuit active to energize said signal controlling relay for clearing the absolute signal, means controlled by each track circuit to control said line circuit adapted to prevent the energization of said signal controlling relay when trolling relay, a second despatcher controlled relay, a circuit controlled by the second despatcher controlled relay to energize the second signal controlling relay for clearing the permissive signal, and means to prevent the energization of the second signal controlling relay unless the first signal controlling relay has been energized and a train entered the first track section in advance of said signals.

11. In combination, an eastbound signal having a clear and a permissive indication, a Westbound signal having a clear and a take siding indication, a first adapted to cause either one or the other of said signals to display a clear indication, a second remote controlled means adapted to cause either the eastbound signal to display a permissive indication or the westbound signal to display the take siding indication, and track circuit means responsive to tranic conditions to render at times the said first remote controlled means ineiiective to cause a clear indication and at all other times to govern the control of the said second remote controlled means over the permissive indication of the eastbound signal.

12. In combination, a main track and a passing siding, a first signal having a clear and a permissive indication to govern traffic moving away from said siding, a second signal having a clear and a take siding indication to govern traffic moving towards said siding, a first despatcher controlled means to control the clear indication of each of said signals, a second despatcher controlled means to control the permissive indication of the first signal and the take siding indica- L remote controlled means tion of the second signal, and track circuit means to govern the control of the first despatcher controlled means over the clear indication of said signals and to govern the control of the second despatcher contr .led means over the permissive indication of the first signal but not over the take indication of the second signal.

13. In combination, a stretch of railway over which traffic normally moves in either direction arranged in track sections, a track circuit for each track section responsive to traffic conditions of the ection, a line circuit controlled by the track circuit of each track section and normally connected to a current source at each end of the stretch, a signal controlling relay at each end of the stretch controlied by said line circuit but normally disconnected, despatcher controlled means to disconnect at times the currentsource at either end of the stretch and to connect the signal controlling relay located at the same end as the disconnected source to the line circuit to thereby energize said relay under clear trail-lo conditions of the track sections, an absolute signal at each endof the stretch cleared when the signal controlling relay at the same end of the stretch is energized, a directional relay associated with each signal controlling relay energized in response to a train entering the stretch at its end of the stretch at a time when the associated signal controllin' relay is energized, and other despatcher controlled means to clear a permissive signal when the directional relay is energized.

ii. In combination, a stretch of railway, an absolute signal and a permissive signal to govern traffic over the stretch, a first signal controlling relay to govern the operation of the absolute signal, a second signal controlling relay to govern the operation of the permissive signal, a starting circuit means rendered active when either of said signal controlling relays functions to operate its signal to initiate a return indication, and another circuit means rendered active when either signal controlling relay functions to operate its signal to determine the character or" the return indication in accordance with the relay that reactions.

15. In combination, a s etch of railway, an absolute signal and a permis ive signal to govern traffic over the stretch, a first signal controlling relay to govern the operation of the absolute signal, a second signal controlling relay to govern the operation of the permissive signal, a starting circuit means rendered active when either of said signal cont-rolling relays functions to operate its signal to initiate a ret u'n indication, another circuit means rendered active when either signal controlling relay functions to operate its signal to determine the character of the return indication in accordance with the relay that functions, and traffic controlled means to prevent the second signal controllinrelay from functioning unless the first signal controlling relay has previously functioned.

16. In combination, a railway having a main track and a passing siding, a switch leading from the main track'to the passing siding, a take siding signal normally inactive, a despatcher controlled relay adapted when energized to render said take siding signal active, a stick circuit for retaining said relay energized and arranged to he closed only when said switch is set for the main track, an indication circuit associated with said relay, and means'eifective to open said stick circuit when said switch is set for the siding whereby said relay is deenergized to restore the signal. to its normal inactive condition and to render the indication circuit active.

PAUL P. STOYER.