US1581607A - Electrically-operated track switch - Google Patents

Description

April 20,1926. 5 1,581,607

' G. A. MEAD ELECTRICALLY OPERATED TRACK SWITCH Filed Dec. '7, 1923 2 Sheets-$heet 1 April 20, 1926.

G. A. MEAD ELECTRIGALLY OPERATED TRACK SWTCH Filed Dec '7, 1925 2 Sheets-Sheet 2 In WI Patented Apr. 20, 1926.

UNITED STATES PATENT OFFICE.

GEORGE A. MEAD, or MANSFIELD, orrro, AssIenoR TO THE OHIO BRASS COMPANY,

on MANSFIELD, OHIO, A oonronnrrou" or NEW JERSEY.

ELECTRICALLY-OPERATED TRACK SWITCH.

Application filed December To all whom it may concern:

Be it known that I, GEORGE A. MEAD, acitizen of the United States of America,residing at h Iansfield, in the county of Richland and State of Ohio, have invented certain new and useful Improvements in an Electrically-Operated Track Switch, of which the following is a specification.

My invention relates to an electrical system for operating switches and is particularly adapted to the operation of track switches by the operator upon a car.

One of the objects of my invention is to provide means for auton'iatically operating the track switch fromthe car through the medium of the motor controller when thrown to either power on or power oil the motors.

Another object of my invention is to supply current to'the system for a predetermined period of time and regardless of the position of the car after having once set the system in operation.

Another object of my invention is to prevent the track switch being thrown to the wrong position afterbeing initially set to the correct position;

A still further object of my invention is to prevent the burning out'of the track switch operating mechanism.

A still further object is to prevent the breaking of destructive arcsby the current collector or trolleywheel. y

Other objects will disclose themselves as further disclosure of my invention is made herein.

My invention resides in the new and novel construction, combination and relation of various parts andicircuits herein described and shown in the drawings.

In the drawings accompanying this specification: i

Fig; 1 shows a diagrammatic scheme of the circuits employed ina car and which are taken into account in the operation of my invention as morefully described here- I inafter.

Fig. 2 is a schematic'drawinoof my in vention showing the relation of the various parts and circuits when'the system is in normalcondition, that is, before and after its operation for positioning the track switch.

7, 1923. Seiiai N0. 679,099.

The switch tongue, however, may

be in any of its positions.

Fig. 3 is a schematic drawing of my invention, showing the arrangement of the parts and circuits immediately after it has been set in operation by the car operator turning his controller tov power 01f,

Fig. i isa schematicdrawing of my invention showing the arrangement of the V21;-

rious' parts and circuits after a predetermined time after the systemhas been set in operation by the car operator setting his controller to power off position.

Fig. 5 is a schematic drawing showing the arrangement of parts and circuits when the system has been set in operation by the operator set-ting his controller to the power on position.

Referring to Fig. 1, it is the object of my invention to provide a system 'by means of which the track switch is automatically and electrically operated to its straight ahead or curve position as may be desued by the car operator merely applying .power on or power off to his motors by means or. his regular motor controller. The system utilizes the principle that when the controller is set to power off no current is flowing through the. motors and when the controller is set to power on heavy current will flow through the motors. Theflow and non-flow of current is made use of in the operation of the system for setting in operation and properly positioning the switch tongue. There are other currents flowing through the car motor which must be taken into account in the designing of the system and which are not under the control of the car operator, or rather are not controlled by the car controller. These are what are known as the heat, light, air compressor circuit, etc, and which shall refer to as the. auxiliary car circuits.

In Fig. 1 l/V represents the trolleywheel' or current collector and T represents the trolley pole by means of which the current collector is mounted upon the car. H indicates'the heaters, indicates the lights and F indicates the air compressor circuit and these circuits when all in operation, together with possibly others, may carry a total of a considerable amount of current.

ing thereover.

The motors for moving the car are indicated by M and the switch by which the current through the motors iscontrolled is indicated by C. All of the circuits within the car are connected to the ground.

In the preferred embodiment of my invention, which is shown in normal condition in Fig. 2, P indicates a trolley pan -which is positioned in connection with the trolley conductor 1 so that the current collector may pass from the trolley wire on to the pan P and out of engagement with the trolley conductor and pass off .ofthe pan P and back into engagement with the trolley conductor 1. The pan P comprises two laterally spaced parallel contact members 2 and 3 which are normally insulated from each other, but so positioned that the current collector may bridge the two in passi I employ av track switch S which is provided with a switch tongue l. The electrical operating mechanism for the tongue 4 comprises. two solenoids 5 and 6, one terminal of each solenoid being connected to the ground G through the conductor 7. Reciprocally operating within the solenoid is a plunger '8 which is drawn in when solenoid 5 is energized and drawn out when solenoid 6 is energized and which is connected to the switch tongue and therefore moves the tongue to one or the other of its positions.

I also employ an electrically operated switch A, which I will term a selector switch,

.as its function isto place one or the other.

of the solenoids 5 or 6 in circuit when the current collector engages the pan P. The switch A is provided with a coil 9 mounted upon an iron core and having one terminal connected to the trolley'wire 1 by the conductor 10, and having itsother terminal connected to the contact member'3 by means of the conductors 11 and 12. The coil 9 Iprefer to make of a few turns of heavy wire as it must withstand a heavy current flowing therethrough and it must also have its ampere turns soproportioned that it will operate to raise the switch arm 13 when the controller C is turned to the power on posiytlOIl with the collector in engagement with the pan P and which will not raise the arm 13 when the controller is turned to the power ofi' position. 'Also the ampere turns mustbe so adjusted that the current flowing through the auxiliary circuits and which It will be seen that the 0011-,

C, motors M to the ground at the same time the contact member 2 will be electrically connected to the trolley wire 1 through the medium of the current collector. The switch A is also provided with two contacts 14 and 15 and the switch arm 13 is normally in engagement with the contact 15 so that the selector switch is normally set for connecting the system to the solenoid 5 and will so remain set if thecollector engages the pan with power oif. It will also be seen that when the switch arm 13 engages the terminal when the collector engages the pan P that the solenoid (3 is placed in circuit withthe system. I also employ an electrically operated switch B whichis provided with a coil 16 mounted upon a magnetic core and has one terminal connected to the contact member 2 by the conductor 17, and the other terminal connected to the ground G by means of the conductor 18. It is not necessary. that the conductor 18 shall be connected directly to the ground, but it may be connected to any other point in the system which will give it a ground connection and without interfering with the functioning of the various parts as required. The resistance of the coil 16 may be sufficiently high so that only a small current flows therethrough, therefore, when the collector leaves the pan P only a slight arcing will take place.

It will be evident that when the pan P is engaged-by the current collector with either power on or power oil that current will flow through the coil 16 thereby energizing the same and picking up the arm 19, and

that the arm 19 will be held in a raised position by the coil 16 as long as the current collector engages the pan P. The switch arm 19 is connected to the trolley conductor 1 by means of the conductors 20 and 21. The conductor 21 can however, be connected to the conductor 10 or it maybe connected to the contactor 3 although I do not prefer this latter connection as then any current flowing through the conductor 21 will flow through the coil 9 and will merely add to the auxiliary car circuit current and, therefore, tend to make it more difficult to properly adjust the winding of the coil 9. When the arm 19 is raised it engages the contacts 22 and 23. The contact 23 is connected by the conductor 24 to one terminal of the coil 25 and the other terminal of the coil 25 is connected to the arm 13 by the conductor 26. It willbe seen that whenever the arm 19 engages the contact 23 and current is flowing therethrough that the coil 25 will be energized and as coil 25 is not wound to act differentially with coil 16 it becomes a holding coil and will maintain the arm 19 in engagement with the con tact 23 whenever current is flowing there through and regardless of whether current 14 throughthe application of power on maintain the branch circuit from the contact;

15 to-the solenoid .5 normally closed and to open this circuit after a predetermined time after the switch B has closed; The switch comprises two coils 27 and 28 dilterentially connected and ot comparatively high resist-Q ance so as to permitonly a small current to pass therethrough as this current flows through-the solenoid and must, therefore, not effect the operation of the solenoid. One end of each coil 27'and' 28 is' connected to the switch arm 29 through the conductor 30, and the switch arm 29 is connected to'the remaining terminalot the solenoid 5 by the a conductor 31. It willfbe noted that the conductors 30, 31, solenoid 5 and conductor 7 term aground connection for the coils 27 ancl'28. The remaining terminal of coll 28 is connected to the source of power through the conductors-32 and 21 aud it will be evident that the coil28 isnormally energized and will therefore, attract and maintain the arm 29 in-engagement with the contact 38 under normal conditions. terminal of the coil 27 is connected to the switch arm 13through the conductor 34 and r it is evident that the coil 27 will have a connection with the source of power whenever the arm 19 i'sclosed through the conductors 34, 26, coil 25, conductor 24, arm 19 and ronductors and 21. When, however, the arm 19 is closed and the arm 13 engages the contact 15the arm 29willbe of substantially the same polarity as the trolley conductor'l V as-these two are gonnected through a low resistance circuit comprising the elements 521. 2c, 19, 24, 25, 2e, 13, 15, 35 and as. lit will be evidentirom this that the conductors 30 and 82 will be connected to points of electrically equal polarity, therefore, the current which has been flowing through the coil 28 will cease as there has been substan l'ially a shunt placed across the terminals of this coil and as the same is true of the coil 27through its connection with the arms 13 and 29 no current will flow through thiscoil and, therefore, the arm 29 will drop after a predetermined timelag due to the dissipation of residual magnetism in the core or other holding means. As soon, however, as the arm 29 has dropped the difierence 0t potential between'the arm 29 and the trolley conductor 1 will be a. maximum and also the same is true between the'arm 13 and the arm 29, and current will flow through each coil 27 and 28 but in opposite directions, and the arm 29 will be maintained in open position through the ditterentialaction ot' the enerheld in .a closed position.

arm 19 is closed and current is flowing through the coil 25 the coil 25 will function 'as a. stick or holding coil, and 'it. willot The remaining fgized coils 27 and 28 so long as the arm rl9 remains closed.

It will beevident that when the switch has been closed by a current collector engagin'gthe pan P with powergoif andenergizing the coil 16, that the arm 19 will be. placed in engagement with'th'e contact '23,- and current will then flow through the sole? noid-5 and the plunger 8 will be drawn in-' wardlyand the track switch tongue moved to the straight ahead position. It will also be evident that as long as theIcontactor engages the pan witli.'power oil that the coil. 16. will vbe energizedand the arm 19 As soon asthe itself maintainthe arm 19 in a r-aisedposi tion as long as current 18' flowing through the circu t;

B5 The circuit will remain closed as I long as the arm 29 is in engagement with thecontact 33, but, as already explained, after a v I predetermined time after the closing otwthe arm 19 the arm 29 will open thereby opening the circuit through the coil 25 and t-hesolenoid 5, and the arm 29 will drop providing the contactor is in engagement with the pan P.' If it is, the arm-29 will be maintained after-the opening of the switch C, as just described, is shown in Fig. 4. It the contactor should be off the pan before the switch 29 opens the current flowing through the coil 25"will maintain the arm 19 closed and the arm 29 will function to open the circuit through the coils 25 and 5, and as soon as thistakes place the coil 25 will become deenergized and the switch: arm 19 will drop,zbut the arm 29 will beimmediately raised upon the dropping of the arm 19 as the coil 27 ot the switch C will be deprived of its energizing current, but the current will continue to flow-through the coil 28 which will pickup the arn'i29and1the sys tem will then be returned to its normal condition. a i i Vhile current is flowingthrough the system, as just described, with the arm 13 in engagement with the contact 15 current will also flow through the coil-36 as it has its terminals connected to the conductor and As a terminal 14 is connected to the-re'maining terminal of the solenoid 6 by the con ductor 411, this furnishes a ground connection for the coil 86 which receives current 7 from the conductor35. connected that it acts difiiereutially tothe coil 9 when; it is energized with the arnrlS :The coil 36 is so inengagement with ithe contact The:

ampere turns, however, of the coil 36 are so proportioned that the'coil 36 will not pick In" order to properly to-affect solenoid: 6, Iinay introduce in the circuit an external resistance 38 by means of which the ampere turns can be properly ad-' justed in the coil 36.

It now a current collector thepan P with power on, asalready explained. heavy current will fiowi through the coil 9 which will pick the arm 1311p and into engagement with the contact 14.

This prevents the How of any ciugrent through the coil 5, but permits the flow-of current through thefcoil 6 when the arm 19 has been picked up through the. energizing of the coil 16 whereu'pon the plunger Sjwill be moved outwardly and the switch tongue 4 moved to the curve position. The-rela tion of the various parts immediately afterthe collector has engaged the pan P with power on 14 and the arm 19 closed, as just described, current will also flow through the. coil 36, but in the opposite direction from that previously described and in'the same direction as current through the coil 9 so that the two will work together and both act as holding coils while the'current collector is passing across the pan P with power on, but as soon as the collectorleaves the panP then the-coil 36 is the only holding coil to mains tain the arm 13 in engagement with the con-.

tact 14. The ground for the 'coil 36 when the arm 13 engages the contact lit is byway of the switch arm 29. As soon asthe arm 19'closes the switch C will start to function to drop the arm 29, but will do sothrough" .the'arm 19 to drop. Immediately'uponthe dropping of the arm 19 the coil 27 is deenergized and the continued energization: of the coil 28 will pickup the arm 29, returning thesystem to. its normal condition as shown in Fig.2.

It has already beenexplained as to the flow of auxiliary car-currents throughthe coil 9 which have a tendency, itsuflicientlylarge, to pick up the arm 13 when the 001- ,is shown diagrammatically in Fig. 5.1 3, p When the arm 13 isclosed on the contact I scribed.

lessthe ampere turns ofthe' coil 9 are so proportioned'that this-will nothappen. It up the arm 13, but will act only as a holdingcoil for the arm 13.

adjust the ampere turns in this circuit,whiclr is of comparatively high resistance soas not has also been explainedin'regard to the difterential action of the coils 9 and 36 when the collectorengages the pan with power off. It-will be evident trom this that the differential action 0t the coil 36 when the system operates with power oli". is beneficial as it tends to neutralizeany picking up I p -etlect of thecoil 9.4. should engage It the-collector should engage the pan P witlrfpo'wer on? and should come to rest with the. collector engaglngthe pan,.1t will 'be necessary for the operator to throw his controller to power on.in order to proceed off the pan, and in. this case the coil 9 might be suthciently energized to pick up the arm 13 and current would then flow through the solenoid 6 thereby setting the switch in the wrong direction as the arm '19, remains closed VBHtIL-fllll flow of current through the coil 9 and prevent .suiiicient energization of the switch A. to pick up the arm 13. In addition to the shunt justdescribed, the coil36 which 'isnergized until the arm 19 opens, acts as a diiterential to the coil 9 and,.thereiiore, it willv help to prevent a. pick up of the arm 1.3 when the operator turns his controller to power on 'underthe conditions. justjdehas dropped, and then the current cannot flow to the solenoid 5. 1

There will beemany changes and modifications in the system just described, such as possibly rearranging some of the connections and circuits, "but-which will stillproduce a system working within thescope ofmy invention; I

I claim-- 1 y 1. A switch operating system comprising in combination, a trolley conductor, a pan provided withtwo contact members to be engaged by a current-collector, an electrically operated track switch, a divided power circuit leadingto said-switch, an electrically operated selector switch connected to one of the contact members for controlling the said The shunt or shortcircuit tothe.

Tim

means controlling the selector switch and.

cooperating with the opening means to open the other divided circuit after the. opening means has opened,

v 2. A switch operating system comprising in combination, a trolley conductor, a pan provided with a pair of contact members to be engaged by acurrent collector, an electrically operated track switch, a branched power circuit leading from thGtl'OllGY con ductor to the track switch, an electrically operated selector switch for controlling the power circuit to operate the track switch to aidesired position, a normally open. switch to open and close the power circuit, means for closing the power circuit and means for holding the switch closed while current to operate the track switch is flowing in the power circuit switch, normally closed means for opening one of the branch circuits after a predetermined time after the normally openswitch has been closed, and means cooperating with the last said switch and with the selector switch to open the other branch circuit after the normally closed switch has opened.

' 3. A switch operating system comprising in combination, a trolley conductor, a pan to be engaged by a current collector, an electrically operated track switch, a normally open branched pgwer circuit leading to the track switch, an electrically operated means normally closing .one of the branch circuits andopening the same after a predetermined time after the collector engages the pan, an

electrically cperated switch to close a second branch circuit when thecollector engages the pan with power on, and means lnterconnecting thejswitch and electrically operated means to control their relativeoperation to open the second branch circuit after a predetermined time but after the first branch circuit has opened. a

4. A switch operating system comprising in combination, a trolley conductor, a pan to be engaged by a current collector, anjelectrically operated track switch, a. normally open branched operating circuit to conduct an operating current to the track switch, a

selector switch to control the said circuit so" that the track switch will be operated in one direction or the other when the collector engages the pan with power on or power off, electrically controlled means normally closing one of the branch circuits and adapt- .ed to open after a predetermined time after current to the operating circuit, and means controlling theother branched c rcult to ,open "the same after the first trically controlled means.

5. A switch operating system comprising in combination, a trolley conductor, a pan to be engaged by a current collector, an electrically operated track switch, a normally open branched operating circuit to conduct an operating current to the track switch, a selector switch to control the said circuit to control the direction of operationof the track switch branch circuit has been opened by said elecwhen the collector engages the pan with power on or power off, and electrically controlled means to open one branchclrcuit aiter the collector engages the pan w1th power oil and to open said branch circuit v and control the opening of another branch circuit after the collectorengages the pan with power on.

6. A switch operating system, comprising in combination, a'trolleyconductor, a pan to be engaged by a current. collector, an electricallyoperated track switch, a normally open branched operating circuit to conduct an operating current to the track switch,*a selector switch to control the saidcircuit to control the dlrectlon of operation of the track switch when the'colle'ctor engages the pan with poweron or power olf, electrically controlled means to open one branch circuit after the collector ens gagesthe pan with power off and" to open said branch circuit and control the opening of another branch circuit after the collector engages the pan with power on and means to normally hold that portion of the power circuit leading to its branch circuits open and to close the same when the collector engages the pan.

7. A switch operating system comprisingin combinatiom'a trolley conductor, a pain, to be engaged by a current collector, an'elec trically operated track swltch, a normally open power circuit to conduct current to the track switch, a selector switch controlling said circuit to operate the track switch to proper position when the collector engages the pan with power on or power off, an electrically operated closing switch to close the power circuit when the collector engages the pan, a holding coil on said closing switch and energized'by the current in said power circuit to hold the closing switch closed after, being initially closed and means tor de-energizing the holding coil after a predetermined time after. the closing switch is closed. I

8; A switch operating system comprising in combination, a trolley conductor, a pan to be engaged by a current collector, an

track switch to a predetermined position when the collector" engages the pan with power off or power on the car motors,

. means to closethe selector switch to normally connect one branch circuit to the power circuit, means operating the selector switch to connect the other branch circuit to i the power circuit when the collector engages the pan with power on, means controlling the selector switch tending to prevent the selector switchoperatingto close the second mentioned branch circuit when the power circuit and first branch circuit is closed and to hold the second branch circuit closed 5 after being initially closed and means to control the opening and closing of the power c rcuit to the branch circuits.

bination of a trolley conductor, a, pan, an electrically operated track switch, a power circuit, branch; circuits leading to the track switch, a selector switch connecting the power circuit to the branch circuitsto operate the track switch to diflterent positions.

electrically operated means cont-rolling one branch circuit to open it after a predetermined time of flow of current therethrougn and means controlling the other branch ci r wit to open the same after it has been closed by the selector switch, the last said means being controlled by the means controlling the first said branch circuit,

10. In a switch operating system, the combination of, a trolley conductor, a pan coinprising two contact members to beengaged by a current collector, an electrically operated track switch S, a selector switch A of by connecting to one or the other 0t two branch circuits leading to the track switch, a normally open power circuit connecting the trolley conductorwith the selector switch, an operating coil 9 for the switch A connected to the trolley conductor and to one contact member and energized suiiiciently to operate the switch A with power on only; a switch B to close the power circuit when the collector engages the pan andhaving an operatingfcoil connected to the other contact member on the pan and having a ground connect-ion andhoperating to close the switch B and hold it closed while the collector engages the pan, the switch 13 also having a coil operating tohold the switch B closed while current is flowing in the power circuit and deriving its operating current from the power circuit; a switch C normally closing one of the branch circuits leading to. the switch S which operates the switch S" with power off, the

switch C having two operating coils so connected that one holds the switch 0 normally closed and both hold the switch. open while the switch B is closed and also operating to open the switch C aftter a predetermined time after theswitch B is closed; an operating coil for the switch A so ,connecte crating to hold the switch A in the power on position when the switch ,A has been operated to the power on position andas long as theiswitch C is closed.

11. In a switch operating system, the comv bination ot,a trolley conductor, apan coin- 9. In a switch operating system, the com-l Inect-iiig to one or the other of two branch circuits leading-to thetrack switch, a normally open power. circuit connecting the trolley conductor with the selector switch,

an operating coil 9 for theswitch A connected to the trolley conductor a di one 0011- tact member and energized sufficiently to operate the switch A with power on only; a switch B to close the power circuit when the collectorengages the pan and having an operating. coil connected to the other contact member and having a ground connection and operating to close the switch Aand hold it closed while the collector engages the pan, the switch A also havinga'coil operating to hold thesw'itch'A closedfwhile current is flowingin the power circuit and deriving its operating current from the power circuit;

a switch C normally closing' one of the branch circuit'sleading to the switch S which operates the switch S-with power oii, the

V switch C having two operating coils so connected that one holds the switch G normally clo'sedand both .hold the switch open while the switch Bis closed and also operating to opentheswitchC after a predetermined time after the switch B is closed; an operating coil for the switch A so connected as i to be energized whenever the system has been set in operation and in which the currentflowtends to counteract the'efitect of current in the coil -9 when the system is 'working power off and tends to assist the current in the coil 9 when the system is working power on, thesaid coil also operating to hold the switch A in the power on position when the switch A has been operated to the power on position and as long as the switch C is closed, means con "trolleci by the switch B toprevent the switch bination of, a source of power, a contact device to be engaged by a current collector, an electrically operated track switch, a selector switch to control the operation of the track switch to a predetermined position whenthe collector engages the contact device with power on or power off and normally held in the power oil? position, and circuits connecting the parts for the above operation, the selector switch having a coil to operate it to the power on position and also having an operating coil in which the current flows in one direction when the system works power on and in the other direction when the system works power off.

13. In a switch operating system the combination of, asource of power, a contact device to be engaged by a current collector, an electrically operated t-r ck switch, a selector switch to control the operation oi" the track switch to a predetermined position.

when the collector engages the contact device with power on or power OH and normally held in the power off position, and circuits connecting the parts for the above operation, the selector switch having a coil to operate it to the power on position and also having an operating coil in which the current flows in one direction when the system works power on and in the other direction when the system works power off, the direction of How being determined by the selector switch being in the power on or power oflf position.

14. A switch operating system in combination, a trolley conductor, a pan to be engaged by a current collector, an electrically operated track switch, a normally open ener- I gizing circuit to conduct an operating current to the track switch, an electrically operated selector switch to control the direction of movement of the track switch, a switch B maintaining the energizing circuit normally open, means for closing the switch B when the collector engages the pan and to hold the switch B closed while the collector engages the pan and means dependent upon the current flowing through the track switch for holding the selector switch closed as long as an operating current flows in the energizing circuit.

15. A switch operating system comprising in combination, a trolley conductor, an electrically operated track switch, a normally open energizing circuit leading to the track switch, a circuit controlling means operated automatically when a car cooperates with the system to transmit current to the track switch to operate the switch to the proper position and an electrically controlled switch operative when the car cooperates with the system to first close the circuit and maintain it closed while current is flowing therein to operate the track switch and thereafter so long as the car cooperates with the system.

16. A switch operating system comprising in combination, a trolley conductor, a pan to be engaged by a current'collector, an electrically operated track switch, a normally dead energizing circuit connected to the track switch, a circuit controlling means for the energizing circuit operated automatically when the collector engages the pan to operate the switch in the proper direction, means other than the collector to energize the circuit when and while the collector engages the pan, and means to maintain the last said means operative and depending forits opera-tion upon an operative current flowing through the track switch.

17. A switch operating system comprising in combination, a trolley conductor, a pan to be engaged by a current collector, an electrically operated track switch, a normally dead energizing circuit connected t the track switch, a circuit controlling means for the energizing circuit operated automatically when the collector engages the pan to operate the switch in the proper directiommeans controlling the energizing of said circuit comprising means operated by the collector engaging the pan to supplycurrent to the said circuit when and while the collector engages the pan and independent means operated by current derived from the said circuit while an operating current is flowing through the track switch.

18. In a mechanism of the class described, a normally open circuit, an electrically operated switch to close the circuit, a coil for operating the switch, means to be engaged and energized by the current collector on a car and connected to the coil, a coil for holding said switch closed and deriving its current from a trolley conductor and a normally closed switch to open the circuit at another point after a predetermined time after the circuit isclosed.

19. A switch operating system comprising in combination, a trolley conductor, a pan, to be engaged by a current collector, an electrically operated track switch, a normally open power circuit to conduct current to the track switch,.a selector switch controlling said circuitto operate the track switch to proper position when the collector engages the pan with power on or power off, an electrically operated closing switch to close the power circuit when the collector engages the pan, a holding coil on said closing switch to hold the closing switch closed after being initially closed and means for tie-energizing the holding coil after a predetermined time after the switch is closed.

20. switch operating system comprising an electrically operated track switch, a branchedvoperating circuit therefor, a controlling switch for positioning said branched circuits and having an operating coil and connections to said coil, means to control the branches respectively of said branched circuit after a predetermined time.

21. A switch operating system comprising in combination, an electrically operated track switch, a branched operating circuit, a controlling switch therefor having an operating and a holding coil, means to deenergize the operating coil after it has functioned to operate the controlling switch and means to open the branches of the branched circuit after a predetermined time, i

Intestiniony whereof I amx my signature.

GEORGE MEAD.

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