US2819388A - Railway traffic controlling apparatus - Google Patents

Description

Jan. 7, 1958 J. M. PELIKAN RAILWAY TRAFFIC CONTROLLING APPARATUS 3 Sheets-Sheet 1 Filed Oct. 15, 1952 INVENTOR. JOIIIZ M pell'li'all BY w. L. W.

HIS ATTORNEY Jan. 7, 1958 A J. M. PELIKAN RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Oct. 15, 1952 3 Sheets-Sheet 2 Y mm m N L m d m m P T M T n n a A m m w A w .L m J Y H, gm 1 m B 1 rw hw m mv a G n. Em m aw #w 4 A mu wwl 5% wwhm w kw #lJ n m AWN m u u m mafq w l w w m QM r fi mm m ARN RH L.

J. M. PELIKAN 2,819,388

RAILWAY TRAFFIC CONTROLLING APPARATUS 3 Sheets-Sheet 3 I' I l I I I i l I I I I I l i l l I I I I l I E I I l I I i l g l I I J Jan. 7, 1958 Filed Oct. 15, 1952 A mm kw Wm h m REQMN SQMN INVENTOR. John M Pelikan w. k squib.

1 1s ATTORNEY aw saw M rxm EIG \sw AE 3% A @EQ United States atent ()1 2,819,388 Patented Jan. 7, 1958 RAILWAY TRAFFIC CONTROLLING APPARATUS John M. Pelikan, Brooklyn, N. Y., assignor to Westinghouse Air Brake Company, Wilmer-ding, Pin, :1 corporation of Pennsylvania Application October 15, 1952, Serial No. 314,843

14 Claims. (Cl. 246-3) My invention relates to railway traffic controlling apparatus. More particularly, my invention relates to apparatus of the type which is known as traflic locking apparatus, by means of which trafiic governing devices, such for example as signals for any given stretch of railway track, are in part manually controllable for governing trafiic movements in both directions, and by means of which such traffic governing devices, after being con trolled for governing traffic movements in one direction over a stretch of railway track, cannot be controlled for governing trafiic movements in the opposite direction while the stretch of track is occupied by a train, or while one traflic governing device remains controlled for authorizing a train to proceed in the former direction into the stretch of track.

One form of traffic locking apparatus which has been used requires joint action by persons at two different control stations for manually controlling trafiic movements in both directions over a stretch of railway track. Each of the two control stations may be provided with an interlocking machine, and each of the interlocking machines may be equipped with a traffic lever which is mechanically interlocked with a signal lever which controls a signal for governing trafiic movements into the stretch of railway track at the corresponding end.

In the particular form of apparatus shown embodying my invention, however, a trafiic control circuit arrangement manually controllable from only one control station is employed, in which polar control relays are energized in series by current of one polarity or the other in a circuit which includes a contact of each of a plurality of track relays and other tratfic controlled relays for a corresponding stretch of railway track and which also includes contacts of two time locking stick relays, one for each end of the stretch of track, controlled in conjunction with a signal for governing traflic movements entering the stretch of track at the corresponding end. Each of the polar control relays is of the polar stick type having polar contacts which, when the corresponding relay becomes deenergized, remain closed in the normal or the reverse position to which they were last operated in response to current of normal or reverse polarity, respectively.

Two track circuits, of the coded type, one for each direction of trallic movements, are provided for each track section between signals, adjacent opposite ends of the stretch of track, which govern traffic movements cut of the stretch of track. The track circuits for a given direction of tramc movement are set up by contacts of the polar control relays when closed in a given or normal position in response to energization of the polar control relays by current of a given normal polarity, and the track circuits for the opposite direction of traffic movement are set up by contacts of the polar control relays when closed in the opposite or reverse position in response to energization of the polar control relays by current of the opposite or reverse polarity.

It has been found that, with such a track circuit scheme, and with contacts of the track relays or of relays controlled by the track relays included in the tratiic control circuit arrangement, a locked-out condition of the traflic control circuit can occur under some conditions. If, for example, the contacts of one or more of the polar control relays should become misplaced, such as by an induced surge of foreign current while the trafiic control circuit is open due to occupancy of the stretch of track by a train, both track circuits for one or more of the track sections are deprived of energized current. It is then necessary for a signal maintainer or other authorized employee to manually efiect restoration of the misplaced polar contacts of the polar control relays to a position in agreement with the polar contacts of the other polar control relays.

Since the traffic control circuit is carried from one signal location to another by line wires on a pole lineparalleling the stretch of track, this circuit is extremely vulnerable to induced transient voltages which result in the surges of foreign current previously mentioned. These transient voltages are induced in the line wires by ligntning or other static charges, by unusual transient voltage conditions in an electric power line usually carried on the same poles, or by accidental, momentary crosses between the traflic control circuit and other circuits of the same pole line. Because of the nature of these induced transient voltages, the current surges occur in portions of the trafiic circuit which are separated by open relay contacts from the rest of the circuit, that is, when the control circuit is open at one or more places by relay contacts released due to a train occupying the stretch of track or due to an entering signal having been cleared. The polar control relays, being very quick acting, are extremely susceptible to operation by these current surges, even though of very short duration, when the relay windings are otherwise deenerg'ized.

An object of my invention, therefore, is the provision of means for protecting against misplacement of the polar contacts of polar control relays connected in series with each other in a control circuit scheme, the misplacement being due to an induced surge of foreign current while the control circuit is open as, for example, in a series railway trafiic control circuit arrangement.

Although, as shown in the accompanying drawings, three polar control relays are energized in series with each other and in series with contacts of a plurality of track relays and other relays, my invention is not limited to this particular form and arrangement of apparatus. My invention can also be applied to control circuits, for other electrical devices, including various other numbers of polar control relays, or even to a control circuit ineluding only one such relay. It is not necessary that a control circuit embodying my invention shall include contacts of track relays or of other relays in series with one or more polar control relays, or that the control circuit shall be normally energized.

My invention can, for example, be applied to a control circuit which includes only one polar control relay and means for energizing it by current of normal and reverse polarities. My invention can also be applied to a traffic control arrangement such as shown in Letters Patent of the United States No. 2,271,510, granted February 3, 1942, to Earl M. Allen for Railway T raflic Controlling Apparatus, in which a traffic control circuit includes four polarized traffic control relays 3FR, SFR, 7FR and 9FR connected in series in a control circuit which is normally deenergized. As is obvious, if my invention were applied to a normally deenergized circuit arrangement including one or more polar control relays as shown in the Allen Pattent No. 2,271,510, it would protect against misplacement of the polar contacts of one or more of the polar control relays, such as by an induced surge of foreign current, while the traflic control circuit is in its normally deenergized condition.

Another object of my inventionds therefore the provision of means for protecting against misplacement, due to an induced surge of foreign current, of the polar contacts of one or more polar control relays connected in a control circuit which includes one or more polar control relays and which is normally deenergized, or which becomes deenergized accidentally, as by a broken connection.

A feature of my invention for accomplishing these objects is the provision of a neutral line relay for each polar control relay, connected in series with the cor responding polar control relay; and a back contact of each of these neutral line relays included in a path connected in shunting relation around the control winding of the corresponding polar control relay in a control circuit which includes the corresponding polar control relay.

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

The accompanying drawings, Figs. 1a, 1b, and 10, when placed end to end in the order named, with Fig. 1a on the left, constitute a diagrammatic view showing one form of apparatus embodying my invention for a stretch of railway track which is provided with a plurality of signals spaced consecutively along the stretch of track for governing traffic movements over the stretch of railway track. This apparatus embodies a plurality of polar control relays, one for each of several signal locations, connected in series, each of the polar control relays having one or more contacts which, when the corresponding relay becomes deenergized, remain closed in the normal or the reverse position to which they were last previously operated in response to current of normal or of reverse polarity, respectively. The apparatus also embodies a plurality of neutral line relays, one for each polar control relay, connected in series with the polar control relays, with a back contact of each of the neutral line relays being included in a path connected in shunting relation around the control Winding of the corresponding polar control relay. Energization of the circuit including the polar control relays and the neutral line relays connected in series, by current of normal or reverse polarity, is manually controllable from only one control station, with contacts of trafiic controlled relays being included in series with the control windings of the polar control relays and the neutral line relays. Two track circuits of the coded type are provided for each of the track sections, one for each direction of traffic movement. The track circuits for a given direction of traific movement are set up by contacts of the polar control relays when closed in the given or normal position, and the track circuits for the opposite direction of traffic movement are set up by contacts of the polar control relays when closed in the opposite or reverse position.

Similar reference characters refer to similar parts in the drawings.

A stretch of railway track is illustrated, over which traflic movements are normally made from left to right, as shown in the drawings, which I shall assume is the eastbound direction, but over which trafiic movements may also at times be made in the opposite or westbound direction. In order to simplify the drawings, the track, comprising two parallel series of track rails, is represented by a single line.

The stretch of track is divided by insulated joints 6 into sections, designated by the reference characters 1T, AT, BT and ST. Each of the track section IT and ST is provided with a track circuit including a suitable source of current such as a battery 7, connected across the rails adjacent one end of the section, and a track relay, designated by the reference character 1TR or STR, respectively, connected across the rails adjacent the oposite end of the section.

A suitable source of alternating current is provided such, for example, as an alternator, designated by the reference character L, shown in Fig. lb, having terminals BX and NX.

Each of the track sections AT and ET is provided with a first track circuit which is at times supplied with coded alternating current adjacent the east end of the corresponding section for controlling eastbound traffic governing means, and is provided with a second track circuit which is at times supplied with coded alternating current adjacent the west end of the corresponding section for controlling westbound traific governing means. Each of the track circuits for section AT includes the winding d of a track transformer, designated by the reference character 3LT, connected across the rails adjacent the east end of the section, and the winding d of a track transformer, designated by the reference character ZRT, connected across the rails adjacent the west end of the section.

For controlling eastbound traflic governing means, the eastbound track circuit for section AT is energized by coded alternating current supplied to winding m of transformer 3LT from terminals BX and NX over front contacts of an eastbound tratlic control relay, designated by the reference character 3EFP. A code following direct current track relay, which may be of the biased neutral type operable by only current of the polarity indicated by the arrow in the symbol for the relay, for the eastbound track circuit for section AT, designated by the reference character ZRTR, is energized by current received from winding m of transformer 2RT over back contacts of a westbound traific control relay, designated by the reference character ZWFP, through a rectifier, designated by the reference character 2R1.

For controlling westbound traflic governing means the westbound track circuit for section AT is energized by alternating current supplied to winding m of transformer 2RT from terminals BX and NX over front contacts of the westbound trafiic control relay ZWFP.

Each of the track circuits for section BT includes the winding d of a track transformer, designated by the reference character 4LT, connected across the rails adjacent the east end of the section, and the winding a. of a track transformer, designated by the reference character 3RT, connected across the rails adjacent the west end of the section. The track circuits for section BT are energized similarly to the track circuits for section AT, as already described, for controlling track relays, designated by the reference characters 3RTR and 4LTR, for controlling eastbound and westbound traffic governing means, respectively.

The rectifiers 2R1, 3R1, 3L1 and 4LI may be of any suitable design such, for example, as the well-known bridge type comprising four asymmetric units, designated by the reference characters i1, i2, i3, and i4, which may be of the well-known copper oxide half-wave rectifier type.

Signals designated by the reference characters RA2 and L2 are located adjacent the opposite ends of track section IT, and signals designated by the reference characters R4 and LA4 are located adjacent the opposite ends of track section ST. A signal designated by the reference character R3 is located adjacent the adjoining ends of sections AT and BT. Signals RA2, R3 and R4 govern eastbound traffic movements, and signals L2 and LA4 govern westbound traflic movements. The signals may be of any suitable design such, for example, as the wellknown color light type, each of which has green, yellow and red light units, designated by the reference characters G, Y and R, respectively, as shown in the drawings.

Track switches such as those designated by the reference characters 1 and 5 may be located in track sections IT and ST, respectively.

Operation of signals RA2, L2, R-tand LA-t and switches 1 and 5 may be controlled manually, at least in part, by

asrasss manually operable devices such, for example, as interlocking machine levers, designated by the reference characters 2V and 4V, for controlling the signals. Each of the levers 2V and 4V has a normal position designated by the reference character 11, in which it is shown in the drawings, a first or eastward position designated by the reference character r to the right, as shown in the drawings, and a second or westward position designated by the reference character f to the left, as shown in the drawings.

A traffic lever, designated by the reference character FV, is also provided adjacent lever 2V, as shown in Fig. la. Lever FV has a normal position n, in which it is shown, and a reverse position r to the right, as shown in the drawing. 7 Contacts operatedby levers 2V, 4V and FV are represented by circles, each of which is placed a reference character to show the position of the corresponding lever in which the contact is closed. Contact 77 of lever 2V, for example, shown in the upper left-hand corner of Fig. la, is represented by a circle in which the reference character 2' is enclosed to show that contact 77 is closed while lever 2V is in its r position only. As another example, contact 16 of lever 2V, shown just below contact 77, is represented by a circle in which the reference character n is enclosed to show that contact 16 is closed while lever 2V is in either its n or its 1' position or at any point between those two positions.

Time locking stick relays, designated by the reference characters ZAS and 4A5, are controlled in part by levers 2V and 4V, respectively, in conjunction with the control of signals by these levers.

Time element devices, shown as time element relays designated by the reference characters 2TE and 4TB, are associated with the control of relays 2A8 and 4A8, respectively, by levers 2V and 4V, respectively. Each of the time element relays 2TE and 4TE is of a type having contacts which become closed only upon the lapse of a measured period of time after the corresponding relay becomes energized.

A signal lighting relay, designated by the reference character RAZER, is controlled in part by lever 2V for controlling signal RA2. Signal lighting relays, designated by the reference characters LA4ER and 4RER, are controlled in part by lever 4V for controlling signals LA4 and R4, respectively. A relay similar to relay 4RER would normally be provided for signal L2. However, since these control circuits are not part of my invention and are not necessary for an explanation of the apparatus shown, the control relay and circuits for signal L2 have been omitted.

Polar control relays are provided, one for each of given signal locations. Each of the polar control relays is designated by the reference character FR preceded by a numeral which is the same as that in the reference character for the corresponding signal.

Neutral line relays are also provided, one for each polar control relay. Each of the neutral line relays is designated by the reference character BPR preceded by a numeral which is the same as that in the reference character for the corresponding polar control relay.

The polar control relays and the neutral line relays are all connected in series in a trafiic control circuit arrangement which includes front contacts of track relays ITR and STR and front contacts of time locking stick relays 2A8 and 4A8, and at times includes front contacts of home signal relays, designated by the reference character HR preceded by a distinguishing prefix, and front contacts of traffic control relays, each of which is designated by the reference character FP preceded by a distinguishing prefix.

The polar control relays and neutral line relays in the traffic control circuit arrangement are energized by current of normal or reverse polarity controlled by a master polar relay, designated by the reference character FSR, which is in turn controlled by pole-changing contacts of traflic lever FV. Under some conditions, themaster polar relay FSR could be omitted, and energization of the polar control relays and neutral line relays by current of normal or reverse polarity could then be controlled directly by pole-changing contacts of trafiic lever FV.

Each of the polar control relays FR, when energized by current of normal or reverse polarity, controls an eastbound or a westbound traffic control relay, respectively, designated by the reference characters EFP and WFP, respectively, preceded by a distinguishing numeral.

Code transmitting devices, each designated by the reference character CT, preceded by the reference character 75 or 180, may be of a type having a contact which, while the corresponding code transmitting device CT is energized, will open and close at a frequency of 75 or times per minute, respectively. Each of the code transmitting devices CT is connected directly across the terminals of a suitable source of current, and therefore its contact is being repeatedly opened and closed at the frequency of 75- or 180 times per minute, as designated by the reference character of the corresponding device CT.

A decoding transformer, designated by the reference character 2T, has a primary winding m which is energized by pulses of current of alternately one polarity or the other controlled by relay ZRTR.

A home signal relay, designated by the reference character ZRHR, for signal RAZ, is energized by current of either the 75 or the 180 code frequency supplied from secondary winding d of transformer 2T through a rectifying contact 57 of relay ZRTR. A distant signal relay, designated by the reference character 2RDR, for signal RA2, is energized through a decoding unit, designated by the reference character 180DU, which is of a well-known type passing only current of the 180 code frequency. Relay ZRDR will therefore be operated only while winding in of transformer 2T is being energized by current of the 180 code frequency.

Decoding transformers, designated by the reference characters 3T and 4T for signals R3 and LA4, respectively, are energized similarly to transformer 2T as just described.

Home and distant signal relays, designated by the reference characters SRI-IR and 3RDR, respectively, for signal R3 are operated similarly to ZRHR and ZRDR, respectively. Home and distant signal relays, designated by the reference characters 4LHR and 4LDR, respectively, for signal LA4 are also operated similarly to relays ZRHR and ZRDR, as already described. A home signal relay, designated by the reference character SLHR, is energized in response to operation of relay 3LTR by coded current. Each of the relays ZRHR, SRHR and 4LHR is of a type which is slow to pick up and slow to release. Relay SLHR is made slow to release by an asymmetric unit, designated by the reference character i5, connected in multiple with its control winding.

A suitable source of current such, for example, as a battery, designated by the reference character 2Q, having terminals designated by the reference characters 2B and 2N, is provided adjacent the west end of the stretch of track, and a suitable source of current such, for example, as a battery, designated by the reference character 4Q, having terminals designated by the reference characters 4B and 4N, is provided adjacent the east end of the stretch of track. A third suitable source of current such, for example, as a battery, designated by the reference character 3Q, having terminals designated by the ref- ; rgnce characters 38 and 3N, is provided adjacent signal Having described, in general, the arrangement and control of the various parts of one form of apparatus embodying my invention, I shall now describe the circuits and operation in detail.

As shown in the drawings, each of the track sections 1T, AT, BT and ST is unoccupied; relays lTR and STR are energized; each of the levers 2V and 4V is in the normal or n position, and therefore each of the signals RA2, L2, R4 and LA4 is displaying the red or stop indication; signal R3 is displaying the yellow or caution proceed indication; relays 2A8 and 4AS are energized; relays 2TB and 4TE are deenergized; traflic control lever FV is in its 11 position, and therefore relay FSR is energized by current of normal polarity. With relay FSR energized by current of normal polarity, its pole-changing contacts 62 and 76 are closed in the normal position for energizing the polar control relays ZFR, 31 R and 41 R, and the neutral line relays ZBPR, 3BPR and dBPR, by current of normal polarity. Relays ZEFP, EEFP, 4EFP, ZRHR, 3RHR, and ZRDR are therefore also energized, while track relays ZRTR and 3RTR are periodically energized by coded track current. Each of the code transmitting devices 75CT and ISOCT is constantly energized, and is therefore repeatedly closing and opening its contacts alternately at a frequency of 75 or 180 times per minute, respectively. Relays ZWFP, RAZER, 3WFP, SLTR, 3LHR, SRDR, LA4ER, 4RER, 4LDR, 4LHR, 4LTR, and 4WFP are deenergized.

In Fig. 1a, code transmitting device 75CT is connected directly across terminals 28 and 2N, and is therefore repeatedly closing and opening its contact 87 at a frequency of 75 times per minute. In Fig. 1/), code transmitting devices '75CT and 180CT are connected directly across terminals 38 and 3N, and are therefore repeatedly closing and opening their contacts at a frequency of 75 and 180 times, respectively, per minute. In Fig. lc, code transmitting devices 75CT and ISOCT are connected directly across terminals 4B and 4N, and are therefore repeatedly closing and opening their contacts at a frequency of 75 and 180 times, respectively, per minute.

In Fig. la, red lamp R of signal HA2 is shown lighted by a circuit passing from terminal 2B, through the back point of contact 8 of relay RAZER, and lamp R of signal RA2 to terminal 2N. The red lamps of signals L2, R4 and LA4 are also lighted by circuits which are similar to the circuit just traced for signal RAZ.

In Fig lb. yellow lamp Y of signal R3 is shown lighted by a circuit passing from terminal 313, through the front point of contact 13 of relay 3EFP, front point of contact 14 of relay SKI-IR, the back point of contact 15 of relay 3RDR, and lamp Y of signal R3 to terminal 3N.

As shown in Fig. 1a, relay 2AS is energized by a stick circuit passing from terminal 28, through contact 16 of lever 2V, contact 17 of relay RAZER, front point of contact 18 of relay 2A8, and the winding of relay 2AS to terminal 2N. Relay 4AS, shown in Fig. 1c, is also energized by a similar stick circuit.

Relay FSR is energized by current of normal polarity passing from terminal 218, through contact 26 of lever FV, winding of relay FSR, and contact 27 of lever FV to terminal 2N. Relays ZBPR, ZFR, 3BPR, 3FR, 4BPR and 4FR are therefore energized by current of normal polarity in a circuit which will be traced later. The polar contacts of each of the relays ZFR, 3FR and 4FR are therefore closed in the normal position.

With contact 30 of relay 4FR closed in the normal position, relay 4EFP is energized by both a pickup and a stick circuit, the pickup circuit passing from terminal 43, through contact 30 of relay 4FR closed in the normal position, contacts 31 and 32 of relays 4A8 and STR, respectively, contact 34 of relay lWFP, and the winding of relay 4EFP to terminal 4N. The stick circuit for relay 4EFP is the same as the pickup circuit just traced except that it includes contact 33 of relay 4EFP instead of contacts 31 and 32 of relays 4A8 and STR.

With relay 4EFP thus energized while relay 4RER is deenergized, winding m of track transformer 4LT is energized by current of 5 code frequency passing from terminal BX, through contact 35 of code transmitting device 75CT, back point of contact 37 of relay 4RER, front point of contact 38 of relay 4EFP, winding m of transformer 4LT, and the front point of contact 39 of relay 4EFP to terminal NX. Alternating current, coded at the frequency of 75 times per minute, is therefore supplied by winding d of transformer 4LT over the rails of section BT to winding (1 of transformer 3RT.

With transformer 3RT thus energized, relay 3RTR is energized by circuit means including Winding m of transformer 3RT, back point of contact 41 of relay SWFP, rectifier 3R1, winding of relay 3RTR, and the back point of contact 40 of relay SWFP. With relay 3RTR thus energized by current coded at the frequency of 75 times per minute, primary Winding m of transformer 3T is being repeatedly energized by current pulses of normal and reverse polarity alternately. The circuit by which the pulses of normal polarity are supplied to winding m of transformer 3T passes from terminal 3B, through the front point of contact 42 of relay SRTR, and the middle portion of winding m of transformer 3T to terminal 3N. The circuit by which the pulses of reverse polarity are supplied to winding m of transformer 3T passes from terminal 3B, through the back point of contact 42 of relay 3RTR, and the lowest portion of winding m of transformer 3T, as shown in the drawing, to terminal 3N.

Relay 3RHR is therefore energized by current passing from winding d of transformer 3T through a rectifying contact 43 of relay 3RTR. With winding m of transformer 3T energized by pulses of current of normal and reverse polarities at the frequency of 75 times per minute, relay 3RDR will not be energized, since current of this frequency cannot pass through the corresponding decoding unit 180DU. With relays SEFP and 3RHR energized and relay SRDR deenergized, lamp Y of signal R3 is lighted by the circuit previously traced.

With contact 44 of relay 31 R closed in the normal position, and with relay 3RHR energized, both a pickup and a stick circuit are closed for energizing relay SEFP. The pickup circuit for relay 3EPP passes from terminal 3B, through contact 44 of relay 3FR closed in the normal position, contact 45 of relay 3RHR, contact 47 of relay 3WFP, and the winding of relay SEFP to terminal 3N. The stick circuit for relay 3EFP is the same as the pickup circuit just traced except that it includes contact 46 of relay 3EFP instead of contact 45 of relay BRHR.

With relays ZiRHR and 3EFP energized, winding m of transformer 3LT is energized by alternating current coded at the frequency of 180 times per minute in a circuit passing from terminal BX, through the front point of contact 48 of relay 3EFP, winding m of transformer 3LT, front point of contact 49 of relay 3EFP, contact 50 of code transmitting device 180CT, and the front point of contact 53 of relay SRHR to terminal NX. Alternating current, coded at the frequency of 180 times er minute, is therefore supplied from winding d of transformer 3LT over the rails of section AT to winding d of transformer ZRT.

Relay ZRTR is therefore energized by a circuit including winding :11 of transformer ZRT, the back point of contact 55 of relay ZWFP, rectifier 2R1, winding of relay ZRTR, and the back point of contact 54 of relay ZWFP. With relay 2RTR thus energized by current coded at the frequency of 180 times per minute, winding m of transformer 2T is energized by current of normal and reverse polarity alternately at the frequency of 180 times per minute. Both relays ZRHR and ZRDR are therefore energized.

Both a pickup and a stick circuit are closed for relay ZEFP, the pickup circuit passing from terminal 2B, through contact 58 of relay ZFR closed in the normal position, contact 59 of relay ZRHR, contact 61 of relay ZWFP, and the winding the relay ZEFP to terminal 2N. The stick circuit for relay ZEFP is the same as the pickup circuit just traced except that it includes contact 60 of relay ZEFP instead of contact 59 of relay ZRHR.

Each of the relays EFP and WFP is of the slow release type.

With the track relays, time locking stick relays, home signal relays ZRHR and 3RHR, and relay 4EFP energized, while relay FSR is energized by current of normal polarity, the polar control relays PR and the neutral line relays BPR are energized by current of normal polarity passing from terminal 2B, through contact 62 of relay FSR closed in the normal position, contacts 63 and 64 of relays 1TR and 2A8, respectively, windings of relays 2BPR and 21 R, contact 66 of relay 2RHR, a line wire to signal location R3, contact 68 of relay 3RHR, windings of relays 3BPR and 3FR, another line wire to the east end, contact 71 of relay 4EFP, windings of relays 4BPR and 4FR, contacts 74 and 75 of relays 4A5 and STR, respectively, a return line wire to the west end, and contact 76 of relay FSR closed in the normal position, to terminal 2N.

I shall assume that a leverman moves lever 2V to the rposition in order to clear signal RA2 for an eastbound train. With lever 2V in the r position, relay RA2ER will become energized by a circuit passing from terminal 2B, through contact 77 of lever 2V, contacts 78 and 79 of relays 1TR and 2FR, respectively, contact 80 of relay 2RHR, and the winding of relay RAZER to terminal 2N. With relay RA2ER energized, contact 8 of this relay will become open, at its back point, thereby extinguishing lamp R of signal RA2, and will become closed at its front point, thereby completing a circuit for lighting green lamp G of signal RA2, this circuit passing from terminal 2B, through the front point of contact 8 of relay RAZER, front point of contact 9 of relay 2RDR, and lamp G of signal RA2 to terminal 2N.

When the leverman moves lever 2V away from its n position toward the r position, contact 16 of lever 2V will become opened, thereby deenergizing relay 2AS. Upon deenergization of relay 2AS, contact 64 of this relay will open the circuit previously traced for the BPR and FR relays.

I shall assume further that, before the eastbound train passes signal RA2, the leverman decides to stop the train at this signal. He will therefore return lever 2V to its n position, thereby deenergizing relay RAZER and thus causing green lamp G of signal RAZ to become ex tinguished and lamp R of this signal to again be lighted. With lever 2V again in its 11 position and relay RA2ER deenergized, an energizing circuit will be completed for time element relay 2TB, this circuit passing from terminal 23, through contact 16 of lever 2V, contact 17 of relay RAZER, back point of contact 18 of relay 2A8, and relay 2TB to terminal 2N.

Upon the lapse of a measured period of time, relay 2TE will close its front contact 19, thereby completing a pickup circuit for relay 2AS, this circuit passing from terminal 2B, 'through contact 16 of lever 2V, contact 17 of relay RAZER, contact 19 of relay 2TB, and the winding of relay 2A8 to terminal 2N. Relay 2A8, upon becoming energized by its pickup circuit, will again complete its stick circuit previously traced, and will also again complete, at its contact 64, the circuit previously traced for the BPR and FR relays.

I shall assume that the leverman later decides to again clear signal RA2 for the eastbound train. He will there fore again move lever 2V to its r position, causing relay RAZER to again be energized, which in turn causes lamp R of signal RA2 to be extinguished and lamp G of this signal to be lighted, as previously described. Relay 2AS will new again be deenergized, causing the polar control relays PR and the neutral line relays BPR to again be deenergized.

When the eastbound train enters section 1T, deenergizing relay 1TR, contact 78 of this relay will open the circuit previously traced for relay RAZER, causing relay RAZER to become deenergized. Lamp G of signal RA2 will therefore be extinguished and lamp R will again be lighted. When relay 1TR becomes deenergized,

10 its contact 63 opens the circuit for the BPR and FR relays at another point.

If, now, while the train is in section 1T, the leverman returns lever 2V to its 11 position, relay 2A8 will become energized by a second pickup circuit, this circuit passing from terminal 28, through contact 1.6 of lever 2V, contact 17 of relay RA2ER, contact 20 of relay 1TR, and the winding of relay ZAS to terminal 2N. With relay 2AS again energized, its contact 64 will be closed in the circuit for the BPR and FR relays, but this circuit will still be open at contact 63 of relay 1TR.

If it is decided to permit the eastbound train to continue its movement past signal R4 at the opposite end of the stretch, a leverman will move lever 4V to its r position, thereby completing a circuit for energizing relay 4RER, this circuit passing from terminal 4B, through contact 81 of lever 4V, various contacts governed by trafiic conditions in advance, not shown but indicated by the dotted line, contact 82 of relay STR, and the winding of relay 4RER to terminal 4N. With relay 4RER thus energized, its contact 12 will open the circuit for the red lamp R of signal R4, and, at its front point, will complete a circuit for lighting either lamp Y or lamp G of this signal, according to traffic conditions in advance, as indicated by the dotted portion of the circuits controlled by the front point of contact 12 of relay 4RER.

With relay 4RER energized, alternating current, coded at the frequency of 180 times per minute will be supplied to winding m of transformer 4LT over a circuit passing from terminal BX, through contact 36 of code transmitting device 1536GT, front point of contact 37 of relay 4RER, front point of contact 38 of relay 4EFP, winding m of transformer 4LT, and the front point of contact 39 of relay 4EFP to terminal NX. Winding d of transformer 4LT will therefore supply alternating current, coded at the frequency of 180 times per minute, to the rails of section ET, for energizing winding d of transformer 3RT.

Relay SRTR will therefore now be energized by current coded at the frequency of 180 times per minute, so that winding m of transformer 3T will now be energized by current of normal and reverse polarity alternately at the frequency of 180 times per minute. Relay SRHR will remain energized as before, and, in addition, relay SRDR will be energized by current of the 180 code frequency passing through the decoding unit 180DU. When relay 3RDR becomes energized, its contact 15 will open at its back point, thereby extinguishing lamp Y of signal R3, and will become closed .at its front point, thereby completing a circuit for lighting lamp G of signal R3, this circuit passing from terminal 313, through the front point of contact 13 of relay 3EFP, front point of contact 14 of relay 3RHR, front point of contact 15 of relay 3RDR, and lamp G of signal R3 to terminal 3N.

The eastbound train, upon entering section AT, will deenergize winding d of transformer 2R1, which in turn will cause relay ZRTR to become deenergized, and then transformer 2T and relays ZRDR and ZRHR will also become deenergized. Relay ZRHR, upon becoming de energized, opens the pickup circuit for relay ZEFP, which, however, remains energized by its stick circuit. When relay ZRHR becomes deenergized, its contact opens the circuit for relay RAZER at another point, and its contact 66 also opens the circuit for relays BPR and FR another point.

With the circuit for relays BPR and FR open, and therefore deenergized, a shunt path is completed around the winding of each of the relays FR through the back points of the adjacent relays BPR. For example, with relay ZBPR deenergized, a shunt path including contact 65 of relay 2BPR is completed around the winding of relay 2FR. With a shunt path thus provided around the wind ing of each of the FR relays, if there should now be an induced surge of foreign current of reverse polarity in the circuit portion, which includes relays 3FR and 4FR,

11 and which is disconnected at contact 66 of relay ZRHR from the circuit portion which includes relay ZFR, the induced current surge would flow through the shunt paths and in that way bypass the control windings of the relays 3BR and 41 R. The induced current surge would therefore not cause the polar contacts of relays 3FR and AFR to be moved to their reverse position.

When the train leaves section 1T, relay ITR will become energized, thereby opening its contact 20 in the second pickup circuit traced for relay ZAS. Contact 78 of relay lTR will now again be closed in the circuit for relay RA2ER, and contact 63 of relay lTR will again be closed in the circuit. for the BPR and FR relays.

When the train enters section BT, winding d of transformer 3R1 will become deenergized, causing relay 3RTR to become deenergized, and in turn causing transformer ST and relays SRHR and 3RDR to also be deenergized. The pickup circuit for relay 3EFP will now be open at contact 45 of relay 3RHR, but relay 3E? will remain energized by its stick circuit.

When relay SRHR becomes deenergized, its contact 68 Will open the circuit for the BPR and FR relays at another point, and its contact 53 will open, at its front point, the circuit previously traced for energizing winding m of transformer 3LT by current coded at the frcquency of 180 times per minute. A circuit will now be completed for energizing Winding m of transformer 3LT by current ended at the frequency of 75 times per min ate, this circuit passing from terminal BX, through the front point of contact 48 of relay SEFP, Winding m of transformer 3LT, front point of contact 49 of relay SEEP, contact 51 of code transmitter 7SCT, back point of contact 52 of relay 3LHR, and the back point of contact 53 of relay SSRHR to terminal NX. When relay 3RHR becomes deenergized, its contact 14 will open, at its front point, the circuit previously traced for lamp G of signal R3, causint this lamp to be extinguished, and will complete a circuit for lighting lamp R of signal R3, this circuit passing from terminal 3B, through the front point of contact 13 of relay 3EFP, back point of contact 14 of relay 3RHR, and lamp R of signal R3 to terminal 3N.

When the train leaves section AT, winding d of transformer 2RT will become energized by current coded at the frequency of 75 times per minute, causing relay ZRTR to in turn become energized by current coded at this frequency. Relay ZRHR will therefore again be energized, but relay ZRDR will remain deenergized. With relay ZRHR again energized, the pickup circuit for relay ZEFP will again become closed at contact 59 of relay ZRHR. Also, with relay ZRHR again energized, its contact 66 will again be closed in the circuit for relays BPR and PR, and contact 80 of relay ZRHR will again be closed in the circuit traced for relay RAZER.

If desired, the leverman can now control signal RAJ. to display a yellow or caution indication for a second eastbound train to pass signal RA2. He will accomplish this by again moving lever 2V to the r position, thereby causing relay RAZER to again become energized by its circuit previously traced. With relay RAZER again encrgized, while relay ZRDR is deenergized, a circuit will be completed for lighting yellow lamp Y of signal RA2, this circuit passing from terminal 218, through the front point of contact 8 of relay RAZER, back point of contact 9 of relay ZRDR, and lamp Y of signal RAZ to terminal 2N.

When the first eastbound train enters section T, relay STR will become deenergized, causing relay -RER to become deenergized, and in turn causing lamp G or lamp Y of signal R4 to be extinguished, and lamp R of this signal to again be lighted. Contact 75 of relay STR will now be open in the circuit for the BPR and FR relays. The pickup circuit traced for relay tEFP will be opened at contact 32 of relay STR, but relay 4EFP will remain energized by its stick circuit previously traced. With relay 4RER again deenergized, winding m of trans- 12 former 4LT will be supplied with current coded at the frequency of 75 times per minute, as previously described.

When the first eastbound train leaves section BT, Winding (1 of transformer 3RT will again be energized by current coded at the frequency of 75 times per minute, causing relay SRTR to in turn become energized by current coded at this frequency, so that transformer 3T and relay 3RHR will also be energized, but relay SRDR will not become energized. Red lamp R of signal R3 will now be extinguished because of the opening of contact 14. of relay 3RHR at its back point, and the yellow lamp Y of this signal will again become lighted by the circuit previously traced.

When both eastbound trains have proceeded beyond signal LA l, and have left section 5T, a circuit will be completed, for energizing the BPR relays, which is the same as the circuit previously traced for energizing the BPR and the FR relays except that it includes contacts 65, and 73 of relays ZBPR, 3BPR and dBPR, respectively. The 'BPR relays, upon becoming energized, will open their back contacts, so that relays ZFR, 31 R and 4FR will again become energized by the circuit previously traced for the BPR and FR relays. All parts of the apparatus will then again be in the condition shown in the drawings.

I shall next assume that a Westbound train is to move over the stretch of track shown in the drawings. A leverman will therefore move lever FV to its 1' position, causing relay FSR to become energized by current of reverse polarity passing from terminal 2B, through contact 28 of lever FV, winding of relay FSR, and contact 29 of lever FV to terminal 2N. Contacts 62 and 76 of re lay FS'R will therefore be moved to the reverse position. While these contacts are moving from the normal to the reverse position, the BPR and FR relays will become de-. energized, and when contacts 62 and 76 of relay FSR reach the reverse position, a circuit will be completed, for energizing the BPR relays by current of reverse polarity, which is otherwise the same as the circuit previously described for energizing the .B PR relays through the back contacts of these relays. As soon as the BPR relays open their back contacts, the relays FR will also become energized by current of reverse polarity.

Each of the relays ZFR, SFR and 41 R, upon becoming energized by current of reverse polarity, will move its polar contacts to the reverse position, thereby deenergiz ing the EFF relays. Release of relays 3EFP and 4EFP interrupts the circuits supplying coded energy to the track circuits of sections AT and BT, respectively. As a result, relays ZRHR, ZRDR, and ERHR are deenergized and release. The traffic control circuit is therefore interrupted at contact 66 of relay ZRl-IR, contact 68 of relay SRHR, and contact 71 of relay iEFP. Contacts of relays ZFR, 31 R, and 4FR, however, remain in their reverse position.

A pickup circuit is now complete for energizing relay ZWFP, this circuit passing from terminal 2B, through contact 58 of relay 2FR closed in the reverse position, contacts 83 and 84 of relays 2A8 and 1TR, respectively, contact 85 of relay ZEFP, and the Winding of relay ZWFP to terminal 2N. Relay ZWFP, upon becoming energized by its pickup circuit, will complete its stick circuit, which is the same as the pickup circuit just traced except that it includes contact 36 of relay ZWFP instead of contacts 83 and 84 of relays 2A3 and lTR, respectively.

With relay ZWFP energized, winding m of transformer ZRT will be energized by current coded at the frequency of times per minute supplied to a circuit passing from terminal BX, through contact 87 of code transmitting device 75CT, front point of contact 54 of relay ZWFP, winding m of transformer ZRT, and the front point of contact 55 of relay ZWFP to terminal NX. Winding d of transformer 3LT will therefore now be energized by A circuit will now be completed for energizing relay 3LTR from winding m of transformer 3LT, this circuit including winding m of transformer 3LT, back point of contact 49 of relay 3EFP, rectifier 3L1, winding of relay 3LTR, and the back point of contact 48 of relay 3EFP. Relay 3LTR will therefore now be periodically energized at a frequency of 75 times per minute, causing contact 88 of relay SLTR to be closed at its front and back points alternately.

Each time when contact 88 of relay 3LTR becomes closed at its back point, a circuit will be completed for charging an energy storing device, designated by the reference character e, this circuit passing from terminal 313, through the back point of contact 88 of relay 3LTR, energy storing device e, and a resistor t to terminal 3N. Each time when contact 88 of relay 3LTR becomes closed at its front point, the energy storing device e will discharge through the winding of relay 3LHR, by a circuit passing from device e, through the front point of contact 88 of relay 3LTR, winding of relay 3LHR, and resistor t back to device e. Relay 3LHR is made slow releasing by asymmetric unit i5 connected in multiple with its control winding, and therefore its front contacts 52, 69 and 89 will remain closed while contact 88 of relay 3LTR is being closed alternately at its front and back points.

A pickup circuit will now be completed for relay 3WFP, passing from terminal 3B, through contact 44 of relay SFR closed in the reverse position, contact 89 of relay SLHR, contact 91 of relay SEFP, and the winding of relay SWFP to terminal 3N. Relay 3WFP, upon becoming energized, will complete its stick circuit, which is the same as the pickup circuit just traced except that it includes contact 94) of relay SWFP instead of contact 89 of relay 3LHR.

A circuit will now be completed for energizing winding m of transformer SRT by current coded at the frequency of 180 times per minute, this circuit passing from terminal BX, through the front point of contact 40 of relay 3WFP, winding m of transformer 3RT, front point of contact 41 of relay SWFP, contact 50 of code transmitting device 18OCT, front point of contact 52 of relay 3LHR, and the back point of contact 53 of relay 3RHR to terminal NX. Current coded at the frequency of 180 times per minute will therefore now be supplied from winding d of transformer 3RT over the rails of section BT, to winding d of transformer 4LT.

Relay 4LTR will now be energized by current coded at the frequency of 180 times per minute in a circuit which includes winding m of transformer 4LT, back point of contact 39 of relay 4EFP, rectifier 4LI, winding of relay 4LTR, and the back point of contact 38 of relay 4EFP. Transformer 4T and relays 4LHR and 4LDR will therefore now be energized through contacts 92 and 93 of relay 4LTR while being repeatedly closed at their front and back points alternately at the frequency of 180 times per minute. When relay 4LHR picks up, the traflic control circuit is again completed, the previously described open contacts 66, 68, and 71 being by-passed, respectively, by contact 67 of relay ZWFP, contact 69 of relay 3LHR, and contact 72 of relay 4LHR. The BPR relays again pick up to open back contacts, and the FR relays are then reenergized by current of reverse polarity.

With relay 4LHR energized, a pickup circuit will be completed for relay 4WFP, this circuit passing from terminal 413, through contact 30 of relay 4FR closed in the reverse position, contact 94 of relay 4LHR, contact 96 of relay 4EFP, and the winding of relay 4WFP to terminal 4N. Relay 4WFP, upon becoming energized by its pickup circuit, will complete its stick circuit, which is the same as the pickup circuit just traced except that it includes contact 95 of relay 4WFP instead of contact 94 of relay 4LHR.

A leverman can now control signal LA4 to display a green or clear proceed indication for a westbound traffic movement, similarly to the manner previously described for controlling lamp G of signal RA2 to display a green or proceed indication for an eastbound train.

I shall now assume that all parts of the apparatus are again in the condition shown in the drawings. I shall assume further that a leverman controls signal RA2 to display the green or clear proceed indication for an eastbound train, and that the eastbound train has moved past signal RA2 over track section IT and onto section AT. I shall assume still :further that, as before applicant made his invention, there are no neutral line relays BPR in series with the FR relays.

I shall also assume that, while an eastbound train is on section AT, a surge of current of foreign reverse polarity is induced, in any manner previously described, and flows through relay BPR, causing the contacts to relay 3FR to move to the reverse position. With contact 44 of relay 3FR moved to the reverse position, relay 3EFP will be deenergized. With relay 3EFP deenergized, the winding of relay 3LTR will be connected with winding m of transformer 3LT through the back points of contacts 48 and 49 of relay SEFP.

Now, when the eastbound train leaves section AT, relay ZRTR at the west end of section AT cannot become energized, because relay 3LTR is connected across the rails at the east end of section AT. Therefore, relay 2RTR, and also relay 3LTR, will remain deenergized and so, when the eastbound train has completed its movement over the stretch of track shown in the drawings and has left track section ET, the circuit for the FR relays will be open at contact 66 of relay ZRHR as well as at contact 67 of relay ZWFP. In order to restore the apparatus to the condition shown in the drawings, it will then be neces sary for a maintainer or other authorized employee to go to the location of signal R3 and manually effect restoration of the contacts of relay 3FR to the normal position in agreement with the contacts of relays 2FR and 4FR.

From the foregoing description, it follows that my invention protects against misplacement of the polar con-' tacts of polar control relays in a control circuit which may include only one polar control relay or which'may include a plurality of polar control relays connected in series, by a surge of current induced by a foreign source while the circuit is deenergized, such as in traific locking apparatus, or in a circuit which is normally deenergized or becomes deenergized accidentally, by providing a neutral relay for each polar control relay, with a shunt path completed around the control winding of the correspond ing polar control relay through a back contact of the neutral relay while the control circuit is deenergized.

Although I have herein shown and 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:

1. In railway trafiic controlling apparatus for a stretch of railway track which is divided into a plurality of sections and is provided with a plurality of traflic governing devices spaced consecutively along said stretch for governing trafiic movements in a first direction and in the opposite or second direction, embodying a plurality of polar control relays connected in series in a traflic control circuit arrangement, each of said relays having polar contacts which when the corresponding relay becomes deenergized remain closed in a normal or a reverse position to which they were last operated in response to current of normal or reverse polarity respectively, in which energization of said traffic control circuit arrangement including said polar control relays connected in series by current of normal and reverse polarities is manually controllable from only one control station, in which two track circuits are provided for each of given sections one for each direction of traffic movements, in

which energization of each of the track circuits for a given direction of traffic movements is controlled by a contact of a corresponding polar control relay when closed in the normal position and energization of each of the track circuits for the opposite direction of trafiic movements is controlled by a contact of a corresponding polar control relay when closed in the reverse position, in which said trafiic control circuit arrangement includes contact means controlled by said track circuits and closed only while said track circuits are energized, and in which each of said trafiic governing devices is controlled by a corresponding one of said track circuits, the combination comprising, a plurality of neutral line relays one adjacent each of said polar control relays connected in series with said polar control relays and said track circuit controlled contact means in said trafiic control circuit arrangement, and a branch circuit path connected in shunting relation around the control winding of each of said polar control relays in said trafiic control circuit arrangement to prevent operation of said polar control relays to their opposite position by transient voltages occurring while said traffic control circuit is open, each of said branch circuit paths including a back contact of the corresponding neutral line relay.

2, In railway traflic controlling apparatus for a stretch of railway track which is divided into a plurality of sections and is provided with a plurality of trafllc governing devices spaced along said stretch for governing traflic movements in a first direction and in the opposite or second direction, embodying a plurality of polar control relays connected in series in a traffic control circuit arrangement, each of said relays having polar contacts which when the corresponding relay becomes deenergized remain closed in a normal or a reverse position to which they were last operated in response to current of normal or reverse polarity respectively, in which enegization of said trafiic control circuit arrangement including said polar control relays connected in series by current of normal and reverse polarities is manually controllable, in which two track circuits are provided for each of given sections one for each direction of traffic movements, in which energization of each of the track circuits for a given direction of trafiic movements is controlled by a contact of a corresponding polar control relay when closed in the normal position and energization of each of the track circuits for the opposite direction of traffic movements is controlled by a contact of a corresponding polar control relay when closed in the reverse position, in which said trafiic control circuit arrangement includes contact means controlled by said track circuits and closed only while said track circuits are energized, and in which each of said trafiic governing devices is controlled by a corresponding one of said track circuits, the combination comprising, a plurality of neutral line relays one for each of said polar control relays connected in series with said polar control relays and said track circuit controlled contact means in said trafiic control circuit arrangement, and a branch circuit path connected in shunting relation around the control winding of each or" said polar control relays in said trafi'ic control circuit arrangement to prevent reversal of the contacts of said polar control relays by current surges induced in portions of said traffic control circuit, each of said branch circuit paths including a back contact of the corresponding neutral line relay.

3. In railway traffic controlling apparatus for a stretch of railway track which is divided into a plurality of sections and is provided with a plurality of signals spaced consecutively along said stretch for governing traffic movements in a first direction and in the opposite or second direction, embodying a plurality of polar control relays connected in series in a trafiic control circuit arrangement, each of said relays having polar contacts which when the corresponding relay becomes deenergized remain closed in a normal or a reverse position to which they were last operated in response to current of normal or reverse polarity respectively, in which energization of said trafiic control circuit arrangement including said polar control relays connected in series by current of normal and reverse polarities is manually controllable, in which two track circuits are provided for each of given sections one for each direction of traflic movements, in which energization of each of the track circuits for a given direction of trafiic movements is controlled by a contact of a corresponding polar control relay when closed in the normal position and energization of each of the track circuits for the opposite direction of traflic movements is controlled by a contact of a corresponding polar control relay when closed in the reverse position, in which one of said signals adjacent each end of said stretch for governing trafiic movements onto said stretch is in part manually controllable, in which said tralfic control circuit arrange ment includes contact means controlled by said track circuits and closed only while said track circuits are energized and also includes contact means normally closed but controlled to become opened when either of said signals adjacent opposite ends of said stretch is manually controlled for displaying a proceed indication, and in which each of said signals is also controlled by a corresponding one of said track circuits, the combination comprising, a plurality of neutral line relays one for each of said polar control relays connected in series with said polar control relays and said contact means, and a branch circuit path connected in shunting relation around the control Winding of each of said polar control relays in said traflic control circuit arrangement to prevent operation of said polar control relays to their opposite positions by induced surges of foreign current occurring while such traffic control circuit is deenergized, each of said branch circuit paths including a back contact of the corresponding neutral line relay.

4. In railway trafiic controlling apparatus for a stretch of railway track which is divided into a plurality of sections, embodying a plurality of polar control relays connected in series in a trafiic control circuit arrangement, each of said relays having polar contacts which when the corresponding relay becomes deenergized remain closed in a normal or a reverse position to which they were last operated in response to current of normal or reverse polarity respectively, in which energization of said traflic control circuit arrangement including said polar control relays connected in series by current of normal and reverse polarities is manually controllable, in which two track circuits are provided for each of given sections one for each direction of trafiic movements, in which energization of each of the track circuits for a given direction of tratfic movements is controlled by a contact of a corresponding polar control relay when closed in the normal position and energization of each of the track circuits for the opposite direction of trafiic movements is controlled by a contact of a corresponding polar control relay when closed in the reverse position, in which said tratfic control circuit arrangement includes contact means controlled by said track circuits and closed only While said track circuits are energized, and in which said track circuits control traflic governing means, the combination comprising, a plurality of neutral line relays one for each of said polar control relays connected in series with said polar control relays and said contact means, and a branch circuit path connected in shunting relation around the control winding of each of said polar control relays in said trafi'ic control circuit arrangement, each of said branch circuit paths including a back contact of the corresponding neutral line relay, whereby the operation of said polar control relays to an opposite position by induced surges of foreign current is prevented.

5. In railway trafiic controlling apparatus for a stretch of railway track which is divided into a plurality of sections, embodying a plurality of polar control relays in which energization of said trafiic control circuit arrangement including said polar control relays connected in series by current of normal and reverse polarities is manually controllable, in which two track circuits are provided for each of given sections one for each direction of traffic movements, in which energization of each of said track circuits for a given direction of traffic movements is controlled by a contact of a corresponding polar control relay when closed in the normal position and energization of each of said track circuits for the opposite direction of traflic movements is controlled by a contact of a corresponding polar control relay when closed in the reverse position, in which said traffic control circuit arrangement includes contact means controlled by a track circuit for each of said sections and closed only while. the corresponding track circuit is energized, and in which said track circuits control traffic governing means, the combination comprising, a plurality of neutral line relays one for each of said polar control relays connected in series with said polar control relays and said contact means, and a branch circuit path connected in shunting relation around the control winding of each of said polar control relays in said traific control circuit arrangement, each of said branch circuit paths including a contact controlled by the corresponding neutral line relay and closed while the corresponding neutral line relay is deenergized, whereby the operation of said polar control relays to an opposite position by induced surges of foreign current is prevented.

6. In combination, a stretch of railway track divided into sections, traffic governing means for governing traffic movements in a given direction and also in the opposite direction over said stretch of railway track, a plurality of polar control relays, a plurality of neutral line relays one for each of said polar control relays, trafiic responsive means for each of said track sections including two track circuits for each of given track sections one for each direction of traflic movements, trafiic responsive contact means for each of said sections controlled by said trafiic responsive means and normally closed but becoming opened when the corresponding track section becomes occupied by a train, a trafiic control circuit arrangement including said polar control relays and said neutral line relays and also said traflic responsive contact means all in series, manually controllable means for effecting energization of said traflic control circuit arrangement by current of normal and reverse polarities, means controlled by normal and reverse polar contacts of said polar control relays for setting up the track circuits for said given track sections for traffic movements in a normal or a reverse direction respectively, means controlled by said traffic responsive means for controlling said traffic governing means for trafiic movements in said normal or said reverse direction according as said normal or reverse polar contacts respectively of said polar control relays are closed, and a branch circuit path connected in shunting relation around the control Winding of each of said polar control relays in said traffic control circuit arrangement to prevent operation of said polar control relays to their opposite positions by induced surges of foreign current occurring while such traffic control circuit is deenergized, each of said branch circuit paths including a contact controlled by the corresponding neutral line relay and closed while the corresponding neutral line relay is deenergized.

7. In combination, a stretch of railway track, trafiic governing means for governing traflic movements in a given direction and also in the opposite direction over said stretch of railway track, a plurality of polar control relays, a plurality of neutral line relays one for each of said polar control relays, traflic responsive contact means for said stretch of track normally closed but becoming opened in response to a trafiic movement over said stretch of track, a traflic control circuit arrangement including said polar control relays and said neutral line relays and also said trafiic responsive contact means all in series, manually controllable means for energizing said traffic control circuit arrangement by current of normal and reverse polarities,

a plurality of branch circuit paths one for each of said polar control relays each connected in shunting relation around the control winding of the corresponding polar control relay to prevent reversal of the contacts of said polar control relays by induced current surges while said trafiic control circuit is deenergized, each of said branch circuit paths including a contact controlled by the corresponding neutral line relay to be closed While the corresponding neutral line relay is deenergized, and means controlled by normal and reverse polar contacts of said polar control relays for controlling said traffic governing means for governing trafiic movements in a first direction or in the opposite direction respectively over said stretch of track.

8. In combination, a plurality of electrical devices, a plurality of polar control relays, each of said relays having polar contacts which when the corresponding relay becomes deenergized will remain closed in a normal or a reverse position to which they were last operated in response to energization of the corresponding relay by current of normal or reverse polarity respectively, a plurality of neutral line relays one for each of said polar control relays, a control circuit including said polar control relays and said neutral line relays connected in series, manually controllable means for energizing said control circuit by current of normal and reverse polarities, a plurality of branch circuit paths one for each of said polar control relays each connected in shunting relation around the control winding of the corresponding polar control relay to prevent reversal of the contacts of said polar control relays by induced current surges while said control circuit is deenergized, each of said branch circuit paths including a contact controlled by the corresponding neutral line relay to be closed when the corresponding neutral line relay is deenergized, and means controlled by said polar contacts of said polar control relays in the normal and reverse positions for selectively controlling said electrical devices in a first or a second given manner respectively.

9. In combination, electrical apparatus, a polar control relay having a polar contact which when the relay becomes deenergized will remain closed in a normal or a reverse position to which it was last operated in response to energization of the relay by current of normal or reverse polarity respectively, a neutral line relay, a control circuit including said polar control relay and said neutral line relay connected in series, control means for effecting energization of said control circuit by current of normal and reverse polarities, a branch circuit path connected in shunting relation around the control winding of said polar control relay in said control circuit, said branch circuit path including a contact controlled by said neutral line relay to be closed when said neutral line relay is deenergized, said branch circuit path being efiective to prevent the operation of said polar control relay by transient voltages while said control circuit is deenergized, and means controlled by said polar contact in its normal and reverse positions for selectively controlling said electrical apparatus in a first or a second given manner respectively.

10. In combination, electrical apparatus, a polar control relay having a polar contact which when the relay becomes deenergized will remain closed in a normal or a reverse position to which it was last operated in response to energization of the relay by current of normal or reverse polarity respectively, a neutral line relay, a control circuit including said polar control relay and said neutral line relay, control means for elfecting energization of said control circuit by current of normal and reverse polarities, a short-circuit branch path connected in shunting relation around the control winding of said polar control relay in said control circuit, said branch path including a contact controlled by said neutral line relay to be closed when said neutral line relay is deenergized, said branch path being effective to prevent the operation of said polar control relay gization of the relay by current of normal or reverse' polarity respectively, a neutral line relay, a control circuit including said polar control relay and said neutral line relay, control means for eifecting energization of said control circuit by current of normal and reverse polarities, a short-circuit branch path connected in shunting relation around the control winding of said polar controlrelay in said control -circuit,"said branch path including a contact controlled by said neutral line relay to be closedwhen said neutral line relay and said polar controlrelay'are deenergized, said branch path being effective to'prevent' the operation of said polar control relay by transient voltages While said relays are deenergized, and means controlled by said polar contactinits normal and reverse positions for selectively controlling said electrical apparatus in a'first or a second given manner respectively.

12. Incombination, electrical apparatus, a polarcontrol relayhaving a polar contact whichwhen the'relay becomes deenergized will remain closed in a normal or a reverse position to which it was last operated in response to energizationof the relay by current ofnormal or reverse polarity respectively, a neutral line relay, a control circuit including said polar-control relay and-said neutral line relay, control means for"effecting energization offsaid control circuit by current of normal and reverse polarities,

a'short-cir'cuitbranch path connected in shunting relationaround the control winding of said polar control relay in said control circuit, said branch path including a contact controlled by'said neutral line relay to be closed when said polar control relay is deenergized, said branch path being effective to prevent the operation of said polar control relay by transient voltages while said polar control relay is deenergized, and means controlled by said polar contact in its normal and reverse positions for selectively controlling said electrical apparatus in a' first or a second given manner respectively.

13. In combination, a stretch of railway track, trafiic governing means for governing traffic movements in a given direction and also inthe' opposite direction .over

said stretch of railway track, a plurality of polar control manually controllable means for energizing. said ,traflic control "circuit arrangement by current of normal and reverse polarities, a plurality of short-circuit branch paths one for each of said polar control relays each connected in shunting relation around the control winding ofthe corresponding polar control relay, each of said branch paths including a contact controlled by the corresponding neutral line relay to be closed While the corresponding neutral line relay is'deenergized, said branch paths being effective to prevent reversal of the contacts of said polar control relays by induced current surges while said traffic control circuit is deenergized, and means controlled by normal and reverse polar contacts of said polar control relays for controlling said traific governing means for'governing trafiic movements in a first direction or in the opposite direction respectively over said stretch of track.

14. In combination, a stretch of railway track, traflic governing means fortgoverning trafiic movements in a given direction and also in the opposite direction over said stretch of railway track, a plurality of polar control relays, a plurality of neutral line relays one for each of said polar control relays, traffic responsive contact means for said stretch of track normally closed but becoming opened in response to. a trafiic .movement over said stretch of track, a trafiic control circuit arrangement including saidpolar control relays and said neutral line relays andalso said trafiic responsive contact means all in series, manually controllable means for energizing said traffic control circuit arrangement by current of normal and reverse polarities, a plurality of short-circuit branch paths one foreach of said polar control relays each connected in shunting relation around the control Winding of the corresponding'polar control relay, each of said branch'paths including a contact controlled by the corresponding neutral line relay to be closed while the corresponding polar control relay is deenergized, each said branch path being effective to prevent operation of the corresponding polar control relay by transient voltages while said corresponding polar relayis deenergized, and means controlled by normal and reverse polar contacts of said polar control relays for controlling said traflic governing means for governing traffic movements in a first direction or in the opposite direction respectively oversaid stretch of track.

References Cited in the tfile of this patent UNITED STATES PATENTS 1,248,942 *Sprague Dec. 4, 1917 1,322,148 Sprague Nov. 18, 1919 2,271,510 Allen Feb. 3, 1942 2,343 ,001 Cohen Feb. 29, 1944 2,366,776 'Fail'or Jan. 9, 1945 2,618,740 Grosjean 'Nov. 18, 1952 2,697,778 Hursh, Dec. 21, 1954

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