US2209438A - Railway switch controlling apparatus - Google Patents

Description

July 30, 1940.

H. s. YOUNG 2,209,438

RAILWAY SWITCH CONTROLLING APPARATUS Filed Nov. 1, 193a HIS ATTOYRNEY Patented July 30, 1940 UNITED, STATES PATENT F RAILWAY SWITCH CONTROLLING "APPARATUS Henry S. .Young, Wilkinsburg, Pa., assignor to The Union Switch & Signal Company, SWISS- vale, Pa., a corporation of Pennsylvania Application November 1, 1938', Serial No. 238,232 7.Clai 1ns. (01.246-219) My invention relates to railway switch controlling apparatus, and particularly to apparatus of the type involving electrically controllable switch operating means, and manual switch operating 5 means, together with a selector for adapting the Switch for operation by either operating means.

One feature of my invention is the provision of means requiring operation of manual control means before the switch'can be operated by the 10 electrically controllable switch operating means after the switch has beenoperated by the manual switch operating means. Another featureof my invention is the provision of novel means for preventing the storage of manual control of a switch if the manual control means should be operated while tramc conditions adjacent the switch are not safe for the switch to'be operated.

The apparatus of my'invention is an improvement over that disclosed in the copending applizocation Serial No. 323,286, filedDecember 3, 1928 by Lester E. Sprayfor Multiple control: appa-' ratus.

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

In the accompanying drawing, Fig. '1 is a dia-' grammatic view showing one" form of apparatus.

WR. The arrangement shown'in Fig. 1 also'prevents the storage of control by the manual 'control means in the event that the'manual control means is operated while unfavorable traffic conditions exist adjacent the switch. Fig. 2 is a modification of the apparatusshown in Fig. I in which relay WS is energized by a circuit which 40 is separate from the circuit for energizing relay Similar reference characters refer to. similar parts in each of the views.

Referring first to Fig. 1, the reference characters I and la designate the track rails ofa stretch of railway track Y divided by insulated joint 2 to form a section A B in which a track switch W is located. Section A-B is provided with a track circuit comprising a battery designated by the reference character 3 conne'ctedacross the rails adjacent one end of the section and'a track relay designated by the reference character TR, connected across the rails adjacent the opposite end of the section;

Electrically controllable": switch?! operating-'- means, such for example as an electric motorM, V is provided for normally operating switch W fromeach of its extreme positions to the other. Manual switch operating means, such for example as a lever 12, is also provided for at times operating;- 5 switch W manually. A, selector, such for example as a lever VS, is provided with means, such for example as a link 4, for adapting switch W; for operation by motor M or by lever'o according as lever VS is in a normal position-n or a 1'0 reverse position r, respectively. I Operated in conjunction with switch W isr'a' movable contact element 13 which engages a fixed; contact element l3a while switch W is in the normal position or is in any other position between the normal position and a given intermediate point in the travel of the switch; Movable contact element l3 also engages a second fixed contact element 131) while the switch is in its reverse position or in any other position'be- 20- tween the reverse position and'a second given intermediate point in the travel of the switch. The opening between fixed contact elements I311 and l3b is preferably-just enough'to prevent short circuiting by the movable contact element 25' I3. Also operated in conjunction withswitch W is a movable contact element 25 contacting a fixed contact element 25:; at all times except when switch W is in its reverse position. Contact element 25 also connects with a second fixed 30' element 251) at all times except when switch'W is in the normal position.

Operation'of motor M for moving switch W to its normal and reverse positions is controlled by normal and reverse relays N and R, respectively, and by relay WS. Relays N and R, are in turn controlled by polarized switch relay WR, by slow release stick relay WS, by an overload relay DS, and by switch contacts 25 251) and 25-4511, as well as over a pair of conductors 9 and I8, 46 through contacts operated by switch locking relays LMR and RMR, and track relay and also through pole changing contacts 5 and 22 of manual control means such for example as a lever V. r

Each of the levers V, VS and 'v has a normal position n and a reverse position 1 Selector lever VS is equipped with a contact II which is closed only when its lever is in the n position. Overload relay DS has a pick-up winding 3| energized in series with motor M, and a stick winding 35 energized over conductors 9 and I8. Under usual conditions, the operating current for motor M is insufiicient in magnitude to cause 'ov erload relay DS to operate its contacts 21 and 31' A 551? resistor 30 having a positive temperature coefficient of resistance is connected in multiple with pick-up winding 3i of relay DS, and hence if motor M draws an excessive amount of current, or if the normal operating current flows for an excessive period of time, such for example as when there is some obstruction to the movement of switch W, resistor 30 will become heated by such excess current or by the normal current for an excessive period of time, causing an increase in its resistance. t ,of resistor 30, the current flowing through winding 3| of relay D8 will be increased in magnitude, causing contacts 21 and 31 of relay DS to be operated. 1 Stick relay WS is energized in a. given direc tion by current of normal or reverse polarity from conductors 9 and I8, through a plurality of asymmetric units IO, I6, 23 and 24 which may be of th well-known copper oxide rectifier type.

Polarized switch relay WR is energized by current of normal or reversepolarity from conductors 9 and 18, through a contact of relay WS,.for operating the polar contacts of relay W'R to normal and reversepositions, respectively. Relay WR is of a type which, when the relay is deenergized, retains its polar contacts closed in a position corresponding to the direction of its last previous energization.

Switch locking relays LMR and RMR, may be approach locking relays controlled in any suitable manner, such for example as shown for relay L in a Patent No. 1,956,851 which was granted May 1, 1934 to C. A. Brooks and J. M. Pelikan, for Railway traffic controlling apparatus.

Referring now to Fig.2, the pick-up and stick circuits for relay WS are here shown separate from those for relay W'R. instead of receiving current from the same conductors 9 and I8- as relay WR, shown in Fig. 1. Relay WR is here connected directly across conductors 9 and I8 instead of through a contact of relay WS as in Fig. 1.

Relay WS, as shown in Fig.2, is not of the slow releasing type shown in Fig.1.

Fig. 2 shows no means for preventing storage of control of switch W by lever V, but some means such for example as that which is shown and described for this purposein Letters Patent of the United States, No. 2,097,826, granted to me November 2, 1937 for Railway switch controlling apparatus, may be used.

Having described, in general, each of the two forms of apparatus embodying my invention, I shall now trace in detail the operation of these forms of apparatus.

As shown in the drawing, all parts are in the normal condition, that'is, track relay TR is energized; levers V, V3 and o are in the normal or nposition; switch W is in'its normal position; switch locking relays LMR and R-MR and stick relay WS are energizedypolarized switch relay WR is energized by current of normal polarity; and relays N, R and DS, and motor M are .deenergized. 1

I shall first trace the operation of the form of apparatus shown in Fig. 1..

Both a pick-up circuit and a stick circuit are closed for energizing relay WS in agiven direc tion by current of normal polarity in conductors 9 and 18. The pick-upcircuit which is closed for relay W S passes from terminalb of a suitable source of current not shown in the drawing, through contact 5 of lever V closed in the n position, contacts. 6, 1 and 8 of relays TR, LMR

and RMR, respectively, conductor 9, asymmetric.

Due to the increase in resistance unit ll], winding of relay WS, contact ll of selector VS, conductor ,l2, contact |3--l3a of switch W, asymmetric unit It, conductor l8, contacts I9, 20 and 2! of relays RMR,, LMR, and TR,

respectively, and contact 22 of lever V to terminal 0 of the same source of current. The stick circuit which is closed for WS is the same as the pick-up circuit just traced except that instead of contact |3l3a of switch W included in the pick-up circuit, the stick circuit includes contact M of relay WS and contact [5 of relay WR closed in the left-hand position.

"A normal energizing circuit for relay WR is also closed, and follows the path just traced for the pick-up circuit for relay WS as far as con ductor 9, and thence passes through contact H of relay WS, and the winding of relay WR to conductor I8, and thence by the same path as traced for the pick-up circuit for relay WS to terminal 0'.

I shall assume that the towerman or operator desires to reverse switch W by means of electrically controllable switch operating means, motor M. He, therefore, moves lever V to its r position, closing contacts 5 and 22 in that position. The reverse control circuit for relay WR is now closed, passing from terminal b, through contact 5 of lever V in the r or right-hand position, contacts 2|, 2!] and IQ of relays TR, LMR, and RMR, respectively, conductor l8, winding of relay WR, contact [1 of relay WS, conductor 9, contacts 8, I and 6 of relays RMIR, LMR and TR, respectively, and contact 22 of lever V closed in the right-hand position, to terminal o.

Relay WS being of the slow releasing type, its contacts do not open during the interval between the opening of contacts 5 and 22 of lever V in the left-hand position and the closing of the contacts of relay'WR in the right-hand position. A second'stick. circuit for relay WS is now closed, passing from terminal 11, through contact 5 of lever V closed in the right-hand position, contacts 21, 20 and IQ of relays TR, LMR and RMR, respectively, conductor l8, asymmetric unit 23, winding of relay WS, contact I i of lever VS, conductor l2, contact I 4 of relay WS, contact 15 of relay WR closed in the right-hand position, asymmetric unit 24, conductor 9, contacts 8, I and 6 of relays RMR,'LMR and TR, respectively, and contact 22 of lever V closed in the right-hand position, to terminal 0.

With relay WR energized by current of reverse polarity, a circuit is now complete for energizing relay R, this'circuit passing from terminal I), through contact 5 of lever V in the right-hand position, contacts 2!, 20 and IQ of relays TR, LMR and RMR, respectively, conductor 18, contact 25--25a of switch W, winding of relay R, contact 26"of relay WR closed in the right-hand position, contact 21 of relay DS, contact 28 of relay WS, conductor 9, contacts 8, l and 6 of relays RMR, LMR and TR, respectively, and contact 22 of lever V closedin' the right-hand position, to terminal 0.

Relay R, upon becoming energized,- closes the reverse operating circuit for motor M, passing through terminal I), through contact 29 of relay WS,winding 3| of relay DS in multiple with resistor 30, front point of'contact 32 of relay R,

armature 33 of motor M, back'point of contact 34 of relay N, and field winding 35 of motor M, to terminal '0. Motor M, upon becoming energized by current of reverse polarity, operates switch W, by means including link 4 of lever VS, moving. switch Wto its reverseposition.

The operation of switch W to its reverse position completes a second pick-up circuit for relay WS, passing from terminal 11, through contact 5 of lever V closed in the right-hand position, contacts 2|, 20 and IQ of relays TR, LMR and RMR, respectively, conductor I8, asymmetric unit 23, winding of relay WS, contact II of lever VS, conductor l2, contact l3-l3b of switch W, asymmetric unit 24, conductor 9, contacts 8, I and 6 of relays RMR, LMR, and TR, respectively, and contact 22 of lever V closed in the right-hand position, to terminal 0. r

If there should, from some cause, be an over loading of motor M, perhaps due to an obstruction such for example as a stone or a lump of coal preventing the closing of the points of switch W in thereverse position, the primary winding 3! of overload relay DS would be energized by operating current of increased magnitude for motor 1 M or the normal operating current would continue to energize winding 3i for a longer period of time, causing resistor 30 to increase its resistance, and thereby causing pick-up winding 3| of relay DS to'raise contacts 31 and 2! of relay DS. The closing of contact 31 of relay DS completes a stick circuit for this relay, passing from terminal b, through contact 5 of lever V closed in the right-hand position, contacts 2|, 2!! and IQ of relays TR, LMR, RMR, respectively, conductor l8, asymmetric unit 23, holding winding 36 of relay DS, contact 3'I.of relay DS, conductor l2, contact I 4 of relay WS, contact l5 of relay WR closed in the right-hand position, asymmetric unit 24, conductor 9, contacts 8, 1 and 6 of relays RMR, LMR and TR, respectively, and contact 22 of lever V closed in the right-hand posititon, to terminal 0. The opening of contact 21 of relay DS breaks the circuit traced for relay R, causing this relay to become deenergized and thereby open the reverse operating circuit for motor M. Relay DS will now remain energized by its stick circuit until the leverman returns lever V to the normal position or until traflic conditions adjacent the switch open the contacts of relay TR, LMR or RMR.

I shall now assume that all parts of the apparatus are returned to the normal condition and that it is decided, for some reason, to operate switch W manually by lever 12. A trainman will therefore move lever VS to its r position, opening its contact H and thereby deenergizing relay WS, and disconnecting motor M from switch W by means of link 4 and connecting lever 12 with switch W by means of link 4. I shall further assume that the trainman moves lever o to its r position, reversing switch W, and that he then returns lever VS to its normal position.

With switch W in its reverse position, the first pick-up circuit traced for relay WS is open at contact l3l3a of switch W, and hence the towerman must reverse lever V in order to close the second pick-up circuit traced for relay WS, before motor M can again return switch W to the normal position. With relay WS energized by its come closed. Because ofthe fact that, relay WS,

is of the slow releasing type, the front contacts of this relay will not open between the time the operator restores lever V to the n position and the time the contacts of relay WR become closed in the normal position. i

I shall next assume that switch W is again operated manually by lever 12 and that whilecselector lever VS isstillreversed, the towerman reverses lever V. I shall further assume that the trainman then returns switch W to its normal position, and then restores lever VS to its n position. Before motor M can reverse switch W to agree with the position of lever V, the towerman must now restore lever-1V to the normal position in order to pick up relay WS by the pick-up circuit first traced for this relay.

I shall now assume that a train enters section A-B while switch W. is in the normal position. I shall further assume that while the train is in section AB, the towerman reverses lever V. With the train in section A-B, relay TR will be deenergized causing its contacts 6 and 2| tobe open, and therefore relays WS and WR will be deenergized. Before switch Wcan be reversed by motor M afterthe train leaves section A-B, the towerman must again return lever V to the normal position, and then, after relay WS becomes energized by its first pick-up circuit, he must reverse lever V. Storageof control of switch W by lever V while switch W islocked against operation,

by unfavorable trafilc conditions, is thus pre-.

vented.

I shall next trace the operation of the form of apparatus shown inFig. 2. With lever V in the normal or 11 position as shown in the drawing, relay WR is energized by current of normal polarity passing from terminal b through contact 5 of lever V in thenormal position to the left, contactsfi, 1 and 8 of relays TR, LMR and RMIR, respectively, conductor 9, winding of relay WR, conductor l8, contacts I9; 20 and 2i of relays RMR, LMR and TR, respectively, and contact 22 of lever V closed in the left-hand position, to terminal o.

With relay WR energized in'the normal direction, and with switch Win the normal. position, a first pick-up circuit'is closed for relay WS, passing from terminal 11-, through contact 38 of relay WR, contact 39 of relay WR .closed in the left-hand position, contact l3a l3 of switch W, contact ll of lever VS, and the winding of relay WS, to terminal A stickcircuit is also closed for relay WS, passing from terminal b, through contact M of relay WS, contact H of lever VS, and the winding of relay WS, to'terminal o.

I shall assume that the towerman wishes to reverse switch Wiby means of motor M. He will therefore move lever V to the 1" position, thereby completing the reverse energizing circuit for relay WR, which is the same as the normal energizing circuit previously traced except that contacts and 22 of lever V'willnow occupy the reverse position tov the right instead of the normal position to the left. Relay WR will therefore move its contact 39 to the right-hand position, thus opening the: pick-up circuit previously traced for relay WS. Relay WS will, however, remainenergized' by the ,stick circuit also previously, traced.

With relay WR,-energized by current of reverse polarity, a circuit will be completed for energizing relay R, thiscircuit passing from terminal b through contact '5 of leverV closed in the rightehand position,,'contacts 2|, 20 and I9 ofrelay I andRMR,-. epe9tiYe a tv winding of relay R, contact 25a 25 of switch W, contact 28 of relay WS, back point of contact 4d of relay DS, conductor 9, contacts 8, 7 and 5 of relays RMR, IMR and TR, respectively, and contact 22 of lever V in the right-hand position, to terminal 0.

With relay R, energized, a reverse operating circuit for motor M is completed, passing from terminal b, through the front point of contact 32 of relay R, resistor 3 in multiple with winding 3! of relay DS, armature 33 of motor M, back point of contact 34 of relay N, and field winding 35 of motor M, to terminal 0. Motor M will then move switch W to the reverse position, whereupon a second pick-up circuit will be completed for relay WS, passing from terminal I), through contact 38 of relay WR, contact 39 of relay WR closed in the reverse or right-hand position, contact I3bl3 of switch W, contact ll of lever VS, and the winding of relay WS, to terminal 0.

Iffor any reason there should be an overloading of motor M while switch W is being operated to the reverse position, resistor 33 will become heated and its resistance will increase, causing an increased amount of current to flow through winding 3i of relay DS, and this, together with any other increase in current due to some obstruction, for example, will cause relay DS to close its contact 40 at the front point. Relay DS will then be retained in the energized position by a stick circuit which is the same as the reverse energizing circuit for relay WR as far as conductor l8, and then passes through winding 36 of relay DS, front point of contact 40 of relay DS, conductor 9, contacts 8, l and 6 of relays RMR, LMR and TR, respectively, and contact 5 of lever V to terminal o. Relay DS will now remain energized by means of this stick circuit until the towerman moves lever V from the reverse position or until one of the relays TR, LMR or RMR becomes deenergized.

I shall now assume that a trainman desires to operate switch W to the reverse position by hand. Preparatory to doing this, hewill move lever VS to the r position, thereby opening its contact H and deenergizing relay WS', and disconnecting motor M through link 4, and connecting lever '12 through link 4 with switch W. He will then move lever 12 to the 7 position, thereby reversing switch W. I shall further assume that he then returns lever VS to the normal or n position.

Before relay WS can now become energized to permit operation of switch W to the normal position by motor M, the towerman must move lever V to the reverse position thereby causing relay WR to become energized in the reverse direction in agreement with the reverse position of switch W. With relay WR now energized by current of reverse polarity, the second pick-up circuit traced for relay WS will become closed.

' The towerman will then return lever V to the normal position, completing the normal energizing circuit previously traced for relay W. A

circuit will now be complete for energizing relay N, passing from terminal 71, through contact 5 of lever V in the left-hand position in which it is shown, contacts 6, l and 8 of relays TR, LMR and RMIR, respectively, conductor 9, back point of contact 40 of relay DS, contact 28 of relay WS, contact 25-25b of switch W, winding of relay N, contact 26 of relay WR closed in the left-hand position, conductor l8, contacts I9, 20

1 and 21 of relays RMR, LMR and TR, respectively,

23 of relay WR closed in the right-hand position,

and contact 22 0f lever V in the left-hand position, tozterminal o.

With relay N thus energized, the normal operating circuit for motor'M will be completed, passing from terminal I), through the front point of contact 34 of relay N, armature 33 of motor M, resistor 30 in multiple with winding 3! of relay DS, back point of contact 32 of relay R, and field winding 35 of motor M, to terminal 0. Motor M will therefore move switch W back to the normal position.

I shall next assume that switch W is again operated manually by means of lever 11, and that while selector lever VS is reversed, the towerman reverses lever V. I shall further assume that the trainman then returns switch W to the normal position by means of lever 12, and that he then returns lever VS to its n position. Before motor M can now reverse switch W, the towerman must return lever V to the normal position in order to energize relay WS.

From the foregoing description and the accompanying drawing, it follows that I have so arranged the control of a stick relay WS by a dual control selector VS and by a track switch and by manual control means for the switch that an operation of the manualcontrol means is required before the switch can be operated by electrically controllable switch operating means, such for example as a motor M, after the switch has been operated manually. I have also provided novel means for preventing storage of control of the switch by the manual control means if the manual control means is operated while unfavorable traffic conditions prevent operation of the switch.

Although I have herein shown and described only two forms of railway switch controlling 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 combination, a stretch of railway track including a switch, electrically controllable switch operating means, manual switch operating means, a selector having a normal and a reverse position, means controlled by said selector for adapting said switch for operation by said electrically controllable switch operating means or by said manual switch operating means when said selector occupies the normal or reverse position respectively, manual control means operable to a normal or a reverse position, control circuits including said manual control means for controlling operation of said electrically controllable switch operating means for operating said switch to its normal and reverse positions respectively, a trafiic responsive contact closed only when said stretch of track is unoccupied adjacent said switch and other control circuits also including said manual control means and including said trafiic responsive contact and controlled by said switch and also by said selector for requiring an operation of said manual control means before said electrically controllable switch operating means can be operated after said switch has been operated by said manual switch operating means.

2. In combination, a railway track switch, electrically controllable switch operating means, manual switch operating means, a selector having a normal and a reverse position, means confs'aid manualf controlmeans and also by a; polar :':.contact of said polarized relay for :retaining' said ;.stick relay-energized only when said'trafil'c con-- ;ditions aresafe for said switch to be operated and only-.whensaidmolar contact and said man- 1 trolled bysaid selector foradapting said switch for operation 'byrsaid electrically Controllable switch operating means or by said manual switch operating means when said selector occupies the normal or reverse'position respectivelyya polarized relay,.manual control means operable to a normalland a reverse position, normal and reverse control circuits for said polarized relay including said manual control means-in the normaland the reverse position respectively and controlled by traffic conditions "adjacent said switch for energizing saidzpolarized relay. by current of normal or reverse polarity only when traffic conditions adjacent said switch are suitable for said switchto be operated, normal and reverse control circuits for said electricallycontrollable switch operating means also including said manual control means in the normal and reverse position respectively and controlled by a normal and a reverse polar contact respectively of said polarized relay, and means controlled by said manual control means and by said switch and also by said selector and including a contact closed only under clear track conditions adjacent said switch for requiring an operation of said manual control means after said switch has been operated by said manual switch operating meansbefore said switch can again be operated by said electrically controllable switch operating means.

3. In combination, a railway track switch, electrically controllable switch operating means, manual switch operating means, a selector having a normal and a reverse position, means controlled by said selector for adapting said switch for operation by said electrically controllable switch operating means or by said manual switch operating means when said selector ocupies the normal or reverse position respectively, a polarized relay, manual control means operable to a normal and a reverse position, normal and reverse control circuits for said polarized relay controlled by said manual control means in the normal and the reverse position respectively and by tranic conditions adjacent said switch for energizing said polarized relay by current of normal or reverse polarity only when trafiic conditions adjacent said switch are suitable for said switch to be operated, a stick relay, pick-up circuits for said stick relay controlled by said switch and by polar contacts of said polarized relay closed in corresponding positions and also controlled by a front neutral contact of said polarized relay, a stick circuit for said stick relay controlled by said selector and closed only when said selector is in the normal position, and normal and reverse control circuits for said electrically controllable switch operating means controlled bya normal and a reverse polar contact respectively of said polarized relay and also by a front contact of said stick relay.

4. In combination, a railway track switch, a stick relay, a polarized relay having polar contacts which when the polarized relay is deenergized remain closed in the position corresponding to the direction of its last energization, manual control means having a normal and a reverse position, pick-up circuit means controlled by trafllc conditions adjacent said switch and by said manual control means and also by said switch for energizing said stick relay only when said traflic conditions are safe for said switch to be operated and only when said switch and said manual control means occupy corresponding positions, stick circuit means controlled by said traffic conditions adjacent said switch and by ual control means occupy corresponding positions,

normal and reversecontrol circuits. including a frontcontact of saidv stick relay and controlled by saidjmanual. control means in the normal and reverse positions respectively, for energizing saidr polarized-relay: by current. of' corresponding polarity, Land; means controlled by polar contacts of said polarized relay closed in thenormal and reverse positionszfor operating said switch to its normal and reverse positions respectively.

5. In combination, a railway track switch, a

Zstick' relay, a polarized relay having. polar ,contacts: which iwhen the' polarized: relay is deenerbe operated and only when said switch and said manual control means occupy corresponding positions, stick circuit means controlled by said trafiic conditions adjacent said switch and by said manual control means and also by a polar contact of said polarized relay for retaining said stick relay energized only when said trafiic conditions are safe forsaid switch to be operated and only when said polar contact and said manual control means occupy corresponding positions, normal and reverse control circuits including a front contact of said stick relay and controlled by said manual control means in the normal and reverse positions respectively for energizing said polarized relay by current of correing to the direction of its last energization,

manual control means having a normal and a reverse position, a pair of conductors, means controlled by trafiic conditions adjacent said switch and by said manual control means in the normal and the reverse position for supplying current of normal or reverse polarity respectively to said pair of conductors only when said traffic conditions are safe for said switch to be operated, a plurality of asymmetric units, pickup means ineluding said asymmetric units and controlled by said switch in the normal and the reverse position for transmitting current of normal or reverse polarity respectively from said conductors for energizing said stick relay in a given direction, stick means also including said asymmetric units but controlled by a normal and a reverse polar contact of said polarized relay for transmitting current of normal and reverse polarity respectively from said conductors in said given direction for retaining said stick relay energized, means including a front contact of said stick relay for transmitting current of normal and reverse normal or reverse polarity respectively and said stick relay is energized.

'7. In combination, a railway track switch, a

stick relay, a polarized relay, manual control means having a normal and a reverse position, a pair of conductors, means controlled by traffic conditions adjacent said switch and by said -manual control means in the normal and the reverseposition .for supplying current of normal or reverse polarity respectively to said conductors only whensaid traific conditions are safe for said switch to be operated, a plurality of asymmetric units, pick-up means including said asymmetric units and controlled by said switch in the normal and thefreverse position for transmitting current of normal or reverse polarity respectively from said conductors for energizing said stick relay in a given direction, stick means also including said asymmetric units for transmitting current of normal and reverse polarity from said conductors for retaining said stick relay energized in said given direction, means including a front contact of said stick relay for transmitting current of normal and reverse polarities from said conductors for energizing said polarized relay, and means controlled by said stick and polarized relays for operating said switch to its normal and reverse positions when said polarized relay is operated by current of normal or reverse polarity respectively and said stick relay is energized.

HENRY S. YOUNG.

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