US2315032A

US2315032A - Control apparatus

Info

Publication number: US2315032A
Application number: US420487A
Authority: US
Inventors: Henry S Young
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1941-11-26
Filing date: 1941-11-26
Publication date: 1943-03-30
Anticipated expiration: 1960-03-30

Description

March 30, 1943. H. s. YOUNG CONTROL APPARATUS 2 Sheets-Sheet 1 Filed NOV. 26, 1941 5 are. ("1

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March 30,1943,

H. s. YOUNG,

CONTROL APPARATUS Fil ed Nov. 26, 1941 2 Sheets-Sheet 2 Lac/fizzy are. Station MsATMR/VEV.

Patented Mar. 30, 1943 UNITED STATES PATENT OFFICE 8 Claims.

office station over a communication system. More particularly, my invention relates to train dispatching or centralized trafiic controlling systems of the class wherein remote control of railway track switches is eiiected by switch mechanisms having a dual selector operable to one position for conditioning the associated switch for manual operation and to another position for conditioning the switch for operation by the switch operating machine.

My invention is applied to a train dispatching or centralized traflic controlling system of the class involving control relays of the polar type effective when deenergized to retain their polar armatures in the last operated position, and which systems are arranged to position the polar armatures of the control relays in response to energy momentarily applied to such relays in response to controls transmitted from a remote oil-ice over a communication system. One such system of this type is shown, for example in Letters Patent of the United States, No. 2,273,231 granted February 17, 1942, to Clarence S. Snavely and Alfred B. Miller.

An object of my invention is the provision, in a system of the class described, of novel and improved means arranged to require a control to be transmitted from the office to the field station in order to obtain operation of a switch by a switch mechanism following a restoration of the selector lever to its power operating position after the selector has been moved to its manual operating position.

Another object is the provision in a system of the class described, of novel and improved means for preventing automatic operation of a switch by a switch mechanism in the event that the selector l ver is restored to its power operating position after the switch is manually operated to a position out of correspondence with remotely controlled apparatus.

The above-mentioned and other important objects and characteristic features which will become readily apparent from the following description, are attained in accordance with my invention by employing a stick relay normallyenergiZed over a stick circuit controlled by a contact closed only in the motor operating position of the dual selector lever, and by including a front contact of the stick relay in the circuit over which the switch operating relay is controlled by the remotely controlled switch control relay. In certain forms of the invention hereinafter described, the stick relay is picked up over a pick-up circuit which is arranged to be closed when a control is received from the control relay, and in other forms of the invention, the stick relay is provided with a pick-up circuit completed when the switch and-control relays are in positions of correspondonce.

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

In the accompanying drawings, Fig. 1 is a diagrammatic view illustrating one form of apparatus embodying my invention. Figs. 1a, 1b and 1c are each fragmentary diagrammatic views showing modifications of portions of the apparatus represented in Fig. 1 and each embodying my invention. Figs. 2, 3 and 4 are each diagrammatic views showing modified forms of the apparatus represented in Fig. 1, and each also embodying my invention. In each of the several views, similar reference characters have been employed to designate corresponding parts.

Referring to Fig. 1, the reference character W designates a railway track switch which is operated by the wel'l known dual selector type of mechanism, comprising a dual selector lever S which operates a link I. When selector lever S is in its normal position, as shown in the drawings, link I conditions the switch for operation by a power switch operating mechanism SM, and when lever S is in its reverse position, link I conditions the switch for operation by a manually operable lever H. Link I also operates a contact member 6 into engagement with a contact 1 when and only when lever S is in its normal or power operating position. In addition, a switch, such as switch W1. shown in Fig. 3, may be provided with a contact member 8 which it operates into engagement with a set of contacts 9 when the itch is in its normal position; and which memher '8 is operated into engagement with contacts II] when the switch is in its reverse position.

The power operating switch mechanism SM may be of any suitable type, such as, for example, an electric or electropneumatic switch machine.

' Switch mechanism SM is controlled in accordance with the usual practice by switch control means comprising a polarized relay WR and it is deemed sufiicient to state that when relay WR is energized by current of normal or one relative polarity to close its front contact 14 and crating circuits will have incorporated therein, 5

as is the usual practice, an overload relay OR arranged to pick up only in the event that mechanism SM draws an excessivelyheavy current. Relay OR will not, of course, be necessary in con-"' nection with electropneumatic switch machines and if mechanism SM is of theielectropneumatic' type, relay OR will then be omitted. V

The reference character WS designates a control relay for controlling switch operating relay WR; Relay WS a polar relay of the polar .stick type that when deenergized retains itsv polar armature in its last operated position. As shown in Fig. 1, relay WS may have two windings, one winding of which when energized is capable of positioningthe polar armature in one of its extreme positions and the otherwinding of which when energized is capable [of positioning the polar armature in its other extreme position. If desired, however, relay WS may have its polar armature positioned by reversing the polarity of current supplied to its energizing windings, as indicated in Figs. 1a and 1b. 1

Relay WS is manually controlled from a central oflice in a well-known manner by means, of any suitable communication or centralized traffic control system, such as for example, that shown in the aforesaid Snavely and Miller Patent No.

For the purposes of the present description, it is deemed suflicientto state that when relay WS is of the two-winding type, shown in Fig. 1, its polar armature is positioned in one extreme position in response to energy applied momentarily to oneof its two windings'in response to a characteristic control code transmitted from the office to the field station, and is positioned inthe other extreme position in response to energy 'momentarily applied to the other of its two windings in response 130a characteristically different control code transmitted from the omce to the field station. When relay WS is of the'type having its polar armature reversibly operated by reversing the polarity of current supplied to its energizing windings, as shown in Figs. 1a and 1b, relay WS then has its polar armature positioned in one extreme position in response to energy of one relative polarity momentarily applied to its energizing winding in response to a characteristic control transmitted from the office to the field station over the communication system, and such relay has its polar armature positioned in the other extreme position in response. to energy of the other relative polarity momentarily applied to its energizing winding in responseto a characteristically different control transmitted from the office to the field station.

The reference character SR designates a stick relay associated with relay WS and cooperating therewith in the control of operating relay WR to require a control to be transmitted from the ofiiceto the field station in order to obtain operation of a switch by a switch machine following'a restoration of the selector lever to its power operating position after the selector has been moved to its manual operating position.

In the normal condition of the apparatus, as represented in Fig. 1, selector lever S is in its normal 0r power operating position to condition switch W for operation by switch mechanism SM; selector lever contact 6-! is closed; stick relay SR is energized over a stick circuit including a source of current, such as a battery not shown but having its opposite terminals designated in the drawings by the reference characters B and 0, its own front contact I6, selector lever contact 'I6, and back contact I! of overload relay OR; switch operating relay WR is energized by current of one relative polarity over a circuit extending'from terminal B through front contact 16 of relay SR, polar contact I8 of relay WS in its normal or left-hand position, as viewed in the drawings, front contact l9 controlled by the electric locking apparatus ordinarily incorporated into switch control apparatus, the winding of relay WR, front contact 20 controlled by the electric locking apparatus, and polar contact 2| of relay WS in its normal position to terminal C. The polarity of current supplied at this time to relay WR is such as'to cause that relay to operate its polar armature to a position in agree-- ment with the position of the polar armature of relay WS. Switch W, as pointed out hereinbefore, occupies a position depending upon the position of the polar armature of relay WR, and hence switch W also agrees in position with-the position of control relay WS.

Operation of switch W may be remotely controlled, as is the usual custom, by the operator at the office station causing a characteristic code to be transmitted over the communication system to position the polar armature of relay WS in its other extreme position. When this happens, the upper or pick-up winding 23 of relay SR becomes energized in series with the one winding of relay WS caused to be energized during the momentary interval that energy is applied to relay WS in responseto the characteristic code received at the field station, [but this energization of winding 23 of relay SR serves no useful function at this time. Relay WS, however, reverses the position of its polar anmature to reverse the polarity of current energizing switch operating relay WR, as is readily apparent from an inspection of the drawing, and as a result relay WR reverses its polar armature l5 to cause switch W to be operated by switch mechanism SM to its other extreme position, wherein switch W agrees in position with both switch operating relay WR and switch control relay WS. Switch W may be restored to its normal condition by the operator causing the characteristic code corresponding to the normal position of relay WS to be transmitted over the communication system.

Switch W may also Joe locally operated by a traimnan. To do this, selector S is first moved 'to its manual operating position to condition switch Wfor manual operation. In this position of lever S, contact 6 is opened to interrupt the previously traced stick circuit of relay SR, whereupon that relay releases to open its front contact I6 and thereby remove relay WS from control of switch operating relay WR. It is apparent, therefore, that remote control of the switch is prevented. at this time should a control be transmitted to a field station in an attempt by the operator to effect operation of the switch. Local operation of the switch may, however, be attained by thetrainmanioperating manual operating lever H. After manual operation has been completed, the selector lever may be restored to its normal or power operating position to condition the switch for operation by the switch mechanism. When this happens, contact 6-1 closes, but relay SR remains released since its stick circuit is now open at its own front contact l6, hence it follows that should the position of the switch, after selector lever S is restored to its power operating position, be out of agreement with the position of the polar armature of switch operating relay WR, no operation of the switch is effected at this time by the switch mechanism since the energizing circuit of relay WR is now open at front contact I6 of relay SR, and front contact [4 of relay WR accordingly remains open to maintain switch mechanism SM deenergized.

'Io regain control of switch W, the operator must cause a characteristic code to be transmittedto the field station. This code may be either i one which causes the polar armature of relay WS to shift to another position, or may be one which corresponds to the position of the polar armature of the relay. In either event,winding 23 of relay SR becomes energized, in series with the winding of relay WS caused to be energized momentarily in response to the received characteristic code, and relay SR accordingly picks up to close its front contact l6 and thereby complete its stick circuit, and also to complete the previously traced circuit of relay WR, whereupon that relay becomes energized by current having a polarity determined by the position of relay WS. With relay WR energized, and its polar armature positioned in accordance with the position of the polar armature of relay WS, operation of switch W by the switch mechanism is, or is not, effected according as the switch is out of, oris in, a position of correspondence with relay WR, respectively.

In Figs. 1a and 1b, the switch control relays W S are of the type that reversibly operate their polar armatures according to the polarity of current applied to their energizing windings. In Fig. 1a,, the upper or pick-up winding 23 of relay SR is connected in series with the winding of relay WS through a full-wave rectifier 25, thus insuring that winding 23 is energized by current of but one polarity regardless of the polarity of current energizing relay WS, Since winding 23 becomes energized each time relay WS becomes momentarily energized, rectifier 25 enables winding 23 to create flux having the same direction as that created by stick winding 22. It follows that when stick winding 22 is energized, winding 23 when energized always assists in maintaining relay SR picked up regardless of the'polarity of current energizing relay WS.

In Fig. 1b, relay WS has connected in series therewith a neutral slow release relay WSP. Relay WSP becomes energized each time energy is applied to relay WS, and relay WSP completes through its front contact 26 a pick-up circuit for relay SR extending from terminal B through front contact 26 of relay WSP,

windings

23 and 22, in series, of relay SR, contact 6-'! operated by selector lever S, and back contact I! of relay OR to terminal C. It is apparent that regardless of the polarity of current energizing relay WSP, the current supplied to the pick-up circuit of relay SR is always of the polarity corresponding to that supplied to the two windings of relay SR over its obvious stick circuit including its own front contact 16.

In an alternate arrangement of the stick circuit of relay SR, indicated in Fig. 1c, the selector lever con-tact 6-'! and back contact ll of overload rel-ay OR may be interposed in the stick circuit of relay SR intermediate one terminal of the source and front contact lb of relay SR. This arrangement has the advantage that the selector lever and overload relay contacts are directly interposed in the control circuit of switch operating relay WR, thereby insuring prompt deenergization of such relay, should either of such contacts become open.

As pointed out heretofore, when switch mechanism SM is of the electric type, relay OR is provided and is arranged to pick up in the event that mechanism SM draws an excessive current due, perhaps, to an obstruction preventing operation of the switch. In the event that overload relay OR is caused to pick up, it is customary to remove energy from the switch mechanism until a suitable code is received by the field station. The arrangements shown in Figs. 1, 1a, 1b and 1c accordingly include a back contact I? of overload OR in the stick circuit of relay SR, and it follows that if relay OR is caused to pick up, relay SR is released to cause both switch operating relay WR and switch mechanism SM to become deenergized. Energy may be applied to the switch mechanism SM only when relay SR is picked up in response to a suitable code received from the office, and after relay OR releases to close its back contact i! and condition the stick circuit of relay SE to be completed.

In Fig. 2, the apparatus represented in Fig. 1 has been modified to incorporate a selector lever repeating relay WLPSR. Relay WLPSR is normally energized over a stick circuit including a source of current, its own front contact 38 and winding, and contact 5--? operated by selector lever S. Relay WLPSR is provided with an obvious pick-up circuit extending from terminal B through the back point of contact it; of relay SR, the winding of relay WLPSR, and contact 6-! of selector lever S to terminal C. The front point of contact finger !8 of relay SR is interposed in its stick circuit, which circuit extends from terminal B through front contact it of relay SR, winding 22 of relay SR, front contact 32 of relay WLPSR and back contact I1. of relay OR to terminal C. Front contact 32 of relay WLPSR is also interposed in the control circuit of relay WR, as is readily apparent from an inspection of the drawings, and it is thus apparent that when selector lever S is moved to its manual operating position to open contact 6-'!, relay WLPSR releases to open its front contact 32 and thereby open the stick circuit of relay SR. If, now, relay SR fails to open its front contact l5, relay WLPSR will remain released after selector lever S is restored to its power operating position and contact 6-! closes, due to the fact that back contact I6 of relay SR is open. The apparatus accordingly'cannot be restored to its normal condition, even should a control be sent from the office to energize relay WS, since front contact 32 of relay WLPSR in its open position interrupts the stick circuit of relay SR, and the operating circuit of relay WR. It follows, therefore, that the apparatus of Fig. 2 functions to check the operation of relay SR by failing to restore the apparatus to control by the remotely controlled relay WS in the event of failure of relay SR to operate.

The apparatus represented in Fig. 3 for controlling a crossover comprising two track switches WI and W2 each operatively connected with a dual selector type of mechanism, incorporates two stick relays, one for each track switch and each normally energized over a stick circuit including itsown front contact and controlled by the selector lever contact of its associated mechanism. The energizing circuit for operating relay WR is carried over

front contacts

34 and 35, in series, of relays SRI and SR2, respectively, and each stick relay is provided with a pick-up circuit completed when and only when the associated switch occupies a position, indicated by a switch operated contact, corresponding to the position of the polar armature of control relay WS. For example, when relay WS is in its lefthand position, and switch WI occupies its normal position, as represented in Fig. 3, relay SRI is provided with a pick-up circuit extending from terminal B through polar contact 36 of relay WS. closed in its normal or left-hand position, contact 9-8-9 operated by switch WI and closed in the normal position of the switch, the winding of relay SRI, and contacts 1-6 of selector levers SI and S2, respectively, to terminal C. Likewise, when switch W2 is in its normal position, as represented in Fig. 3, relay SR2 is then provided with a'pick-up circuit which extends from terminal B through polar contact 36 of relay WS in its normal position, contact 9-8-9 operated by switch W2 and closed in the normal position of switch W2, the winding of relay SR2, and then extends through contacts 1-6 operated by selector levers SI and S2, to terminal C. Whenever either switch WI or W2 is conditioned for manual operation, its associated contact 1-6 is opened, and both stick relays SRI and SR2 become deenergized. Then, when such switch is conditioned for power operation and both selector lever contacts 1-6 are closed, stick relays SRI and SR2 pick up over their respective pick-up circuits provided that the position of the associated switch corresponds tothe position of the control relay WS. For example, ,assume that relay WS is in its normal or left-hand position, and that selector lever SI is moved to its handoperating position, thereby opening its associated contact 6-1 and causing both relays SRI and SR2 to release. After switch WI is manually operated to its reverse position, wherein switch operating contact I-8-I0 is closed and contact 9-8-9 is opened, a restoration of selector lever SI to its normal position results in relay SR2 picking up over its previously traced pick-up circuit, but relay SRI remains released. As a result, switch operating relay WR also remains released, and operation of switch WI by power to its normal position in correspondence with switch operating relay WR and switch control relay WS is prevented.

Relay SRI may be picked up, to restore control relay WS to control of operating relay WR, by the operator dispatching a code to relay WS to cause that relay to operate its polar armature to a position of correspondence with switch WI. When this happens, relay SR2 remains energized over its stick circuit while relay SRI becomes energized over a circuit extending from terminal B through polar contact 36 in its reverse or high-hand position, contact III-B-II] operated by switch WI, the winding of relay SRI, and contacts 6-1 operated by selector levers SI and S2, respectively, to terminal C, and relay SRI accordingly picks up to close its front contact interposed in the energizing circuit of operating relay WR. Relay WR now becomes nergized by current having a polarity such as to cause the polar armature of such relay to op- .erate to its reverse position, whereupon switch mechanism SM2 becomes energized and causes the other switch W2 to operate to its reverse position. To restore the switches to normal, the operator may send the normal cod to relay WS to cause that relay to restore its polar armature to its normal position, whereupon relay WR operates to a position of correspondence to energize mechanisms SMI and SM2 to cause such mechanisms to operate switches WI and W2 to their respective normal positions of correspondence with relays WR and WS.

The switch mechanisms represented in Fig. 3 are preferably of the electropneumatic type, hence no overload protection is provided. Should electric switch movements be employed, however, the apparatus represented in Fig. 3 may be modified to incorporate overload protection, which protection may be provided in any suitable manner, as for example the manner shown and covered in Letters Patent of the United States No, 2,199,952, granted on May 7, 1940, to Claude M. Hines and Bernard E. OHagan. In addition, it is to be understood that the apparatus of Fig. 3 may be modified to control but a single switch, in which event only one stick relay, such as relay SRI, and one switch mechanism, such as mechanism SMI, would be required.

In Fig. 4,'two stick relays SRI and SR2 are provided for cooperating with control relay WS in controlling switch W. Each relay SRI and SR2 is normally energized over a stick circuit controlled by the dual selector lever contact 6-1, and which circuits extend from terminal B through contact 1-6 of selector lever S, back contact I1 of overload relay OR, and then through front contact 31 and the winding of relay SRI to terminal C, or through front contact 38 and the winding of relay SR2 to terminal C.- Relays SRI and SR2 jointly control relay WR in such manner that relay WR may be energized only when both relays SRI and SR2 are picked up to complete a circuit extending from terminal B through front contact 39 of relay SR2, front contact 40 of relay SRI, polar contact M in its normal or left-hand position, as represented in Fig. 4, contact I9 operated by the electric locking,.the winding of relay WR, front contact 23 operated by the electric locking, and polar contact 42 of relay WS in its normal position to terminal C.

Relay SRI is provided with a pick-up circuit extending from terminal B through contact 1-6 of selector lever S, back contact I1 of overload relay OR, contact 43 of relay WS in its normal or left-hand position and the winding of relay SRI to terminal C. Relay SR2 is provided with a pick-up circuit which corresponds to the pickup circuit for relay SRI but which includes polar contact 43 of relay WS in its reverse position and then extends through the winding of relay SR2 to terminal C.

The apparatus of Fig. 4 is arranged to require an operation of relay WS by code in order to restore such relay to control of operating relay WR when selector lever S is restored to its power operating position following a manual operation of switch W. That is, relays SRI and SR2 are released when selector S is operated to its manual operating position to open its contact 6-1. After the selector is restored to its power operating position and contact 6-1 closes, one or the other, but not both, of the stick relays becomes picked up according as polar contact member 43 of relay WS is in one or another of its two positions, re-

spectively. For example, if contact 43 is in its normal position, then the pick-up circuit of relay SRI becomes completed when contact 6'| of the selector closes, and relay SRI picks up while relay SR2 remains released. On the other hand, if contact 43 is in its reverse position, then relay SR2 is picked up while relay SR! remains released. In either event, relay WR remains released since its energizing circuit includes, in series, a front contact of each stick relay. Relay WR is, however, picked up when relay WS is caused to operate its polar contact in response to a control from the central ofiice. When this happens, the picked-up one of the stick relays is maintained energized over its stick circuit, while the other stick relay becomes picked up since its pick-up circuit is now caused to be completed by the operation of polar contact member 43 of relay WS. Relay WR of. course becomes energized when both stick relays are picked up, and it follows that the apparatus of Fig. 4 is arranged so as to prevent an automatic operation of the switch by power when the selector is restored to its power operating position following a manual operation, and that such apparatus is arranged to require a code operation of the control relay in order to restore the control relay to control of the power operating switch mechanism.

Although I have herein shown and described only a few forms of control apparatus embodying my invention, it is understood that various changes and modifications may be madetherein 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 a train dispatching system for railroads, the combination with, a dispatchers ofi'ice, a track switch located at a remote point, and a switch machine provided with a dual selector operable to one position for conditioning said switch for manual operation and to another position for conditioning said switch for operation by said machine, of a stick relay normally energized over a stick circuit including its own front con' tact and governed by a contact operated by said dual selector and closed only when said selector is in its said other position, a control relay of the polar stick type capable when deenergized of maintaining its polar contact in its last operated position, a communication system extending from said dispatchers ofiice to said remote point and capable of positioning the armature of said control relay by energy momentarily applied in response to a control transmitted by said system, a pick-up circuit for said stick relay including a winding of said relay connected in series circuit with a winding of said control relay, and circuit means for causing said switch machine to operate said switch to a position in agreement with the polar armature of said control relay provided that said stick relay is picked up.

2. In a train dispatching system for railroads, a dispatchers office, a track switch located at a point remote from said ofiice, a switch machine provided with a dual selector for selectively conditioning said switch for operation manually or by said machine, a stick relay normally energized over a stick circuit including its own front contact and a contact operated by said selector and closed when and only when said selector conditions said switch for operation by said machine, a control relay of the polar stick type, a communication system extending from said dispatchers ofiice to said remote point for positioning the armature of said control relay by energy momentarily applied to said relay in response to a control transmitted over said system, means con nected in series with the winding of said control relay and energized by the energy positioning said control relay for picking up said stick relay, and circuit means for causing said switch machine to operate said switch to a position of correspondence with the armature of said control relay when said stick relay is picked up.

3. In a train dispatching system for railroads, a dispatchers office, a track switch located at a point remote from said ofiice, a switch machine provided with a dual selector for selectively conditioning said switch for operation manually or by said machine, a two winding stick relay having one winding normally energized over a circuit including its own front contact and a contact operated by said selector and closed when and only when said selector conditions said switch for operation by said machine, a control relay of the polar stick type, a communication system extending from said dispatchers office to said remote point for transmitting controls, a circuit including in series a winding of said control relay and the other winding of said stick relay and to which circuit energy is momentarily applied in response to a control transmitted over said system, said energy functioning to position the polar armature of said control relay and energize said stick relay, and circuit means including a front contact of said stick relay for causing said switch machine to operate said switch to a position of correspondence with the polar armature of said control relay.

4. In a train dispatching system for railroads, a dispatchers ofiice, a track switch located at a point remote from said ofiice, a switch machine provided with a dual selector for selectively conditioning said switch for operation manually or by said machine, a stick relay normally energized over a circuit including its own front contact and a contact operated by said selector and closed when and only when said selector conditions said switch for operation by said machine, a control relay of the polar stick type; a circuit including a winding of said control relay and means for supplying energy of one relative polar ity to said stick relay each time said circuit issupplied with current of either polarity, a communication system extending from said dispatchers ofilce to said remote point for supplying to said circuit energy of one relative polarity or the other for positioning the armature of said control relay in accordance with the polarity of current supplied thereto and for energizing said stick relay with energy of said one relative polarity, and circuit means including a front contact of said stick relay for causing said switch machine to operate said switch to a position of correspondence with the polar armature of said control relay.

5. In a train dispatching system for railroads, a dispatchers office, a track switch located at a point remote from said oflice, a switch machine provided with a dual selector for selectively conditioning said switch for operation manually or by said machine, a stick relay normally energized over a circuit including its own front contact and a contact operated by said selector and closed when and only when said selector conditions said switch for operation by said machine, acontrol relay of the polar stick type, a communication system extending from said dispatchers oiiice to said remote point for transmitting controls, a repeater relay, a circuit including in series a winding of said control relay and the winding of said repeater relay and to which circuit energy is momentarily applied in response 'to'a control transmitted over said system, said energy functioning'to position the polar armature of said control relay and energize said repeater relay, a circuit including a front contact of said repeater relay and the winding of said stick relay for energizing said stick relay each time a control is received at said remote point, and circuit-means including a front contact of said stick relay for causing said switch machine to operate said switch to a position of correspondence with the polar armature of said control relay.

6. In a train dispatching system of the class comprising an oflice and a station interconnected by a communication system, a track switch at said station, a switch machine provided with a dual selector for selectively conditioning said switch for operation manually or by said machine, a lever repeating relay normally energized over a stick circuit including its own front contact and a contact operated by said selector and closed only when said selector conditions said switch for operation by said machine, a stick relay normally energized over a stick circuit including a front point of one of its contacts and a front contact of said lever repeating relay, a pick-up circuit for said lever repeating relay including the back point of said'one contact of said stick relay and'said selector lever contact, a polarized control relay arranged to position its armature in response to energy momentarily applied to said'control relay winding when a control is received at said station over said communication system, means connected in series with the winding of said control relay and energized by the energy positioning said control relay for energizing said stick relay over a pick-up circuit, and circuit means including a front contact of said stick'relay for causing said switch machine to operate said switch to a position of correspondence with the armature'of said control relay. 7 I i.

7.- In a train dispatching system for railroads, a dispatchers ofiice, a track switch located at a point remote from said'oiiice, an electric switch machine operatively connected with said switch,

an overload relay interposed in the energizing circuits of said switch machine and arranged to be picked up when said machine draws excessively heavy current, a stick relay normally energized over a stick circuit including in series a front contact of said stick relay and a back contact of said overload relay, a control relay having a polar armature, a communication system extending from said dispatchers oflice to said remote point for positioning the armature of said control relay by energy momentarily applied to said relay in response to a control transmitted over said system, means connected in series with the winding of said control relay and energized by the energy positioning said control relay for picking up said stick relay, and circuit means including a front contact of said stick relay for causing said switch means to operate said switch to a position of correspondence with the armature of said control relay.

8. In a train dispatching system for railroads,

of the class comprising an ofiice and a station interconnected by a communication system, a track switch at'said station, an electric switch machine having a dual selector for selectively conditioning said switch for operation manually or by said machine, an overload relay interposed in the operating circuits of said switch machine and arranged to be picked up when said machine draws excessively heavy current, a stick relay normally energized over a stick circuit including in series its own front contact and a back contact of said overload relay and a contact operated by said selector and closed when said selector conditions said switch for operation by said machine, a polarized control relay arranged to position its polar armature in response to energy momentarily applied to its winding when a control is received at said station over said communication system, means connected in series with said control relay and energized by the energy positioning the armature of said control relay for energizing said stick relay over a pickup circuit, and circuit means including a front contact of said stick relay for causing said switch machine to operate said switch to a position of correspondence with the armature of said control relay.

HENRY S. YOUNG.