US2183694A - Traffic control system for railroads - Google Patents

Description

Dec. 19,1939. X REE 2,183,694

TRAFFIC CONTROL SYSTEM FOR RAILROADS Filed Feb. 4, 1937 2 Sheets-Sheet 1 spar.

l VENT 53%.?

4 ATTORNEY Dec. 19, 1939.

F. X. REES TRAFFIC CONTROL SYSTEM FOR RAILROADS Filed Fab. 4, 1937 2 Sheets-Sheet 2 U o l 3 INVENTOR BY 72%1 %;q/ ATTORNEY Patented Dec. 19, 1939 UNITED STATES Q, TRAFFIC CONTROL SYSTEM FOR RAILROADS Frank X. Rees, Albany, N. Y., as'signor to General Railway Signal Company,

Rochester,

Application February 4, 1937, Serial No'. 124,060 15 Claims. (01. 246-3 This invention relates to traflic control systems for railroads and has particular reference to a system for the remote control of power operated switch machines.

In interlocking systems of the mechanically interlocked lever type and in types of systems in which the levers are locked by suitable approach looking or detector locking means, the operator is, of course, not able under unsafe conditions to, move the lever, and for that reason cannot tentatively set up an operating condition that may later become effective due to the clearing up of the conditions which formerly locked the lever. In accordance with the present invention, it isproposed to leave the levers free and unlocked 'at all times and provide an electric lock equivalent arrangement whereby in the event that the operator shifts the switch machine control lever while the circuits have the switch machine locked against operation, it is necessary for the operator to restore the switch machine control lever into correspondence with the position of the associated switch machine control relay before control of the switch machine is obtained. Stated another way, in order to operate the switch machine the switch machine control lever must be operated at the time the locking is not effective and, in the event that the switch machine control lever is moved while the locking circuit is in effect, the switch machine will not operate after a train movement over the switch until after the operator moves the control lever to its last effective position. Another object of the present invention is to provide over load protection for the switch machine motor, so arranged that when the overload protective device operates it is necessary only for the operator to restore the switch ma- 4 chine control lever to its original position in ordervto'obtain control of the switch machine. Another object of the presentinvention is to provide means for indicating the electrically unlocked position of the lever and the out-of-correspondence condition of the lever with respect v to the switch points. Other objects, purposes and characteristic features of the invention will be in part apparent and in part brought out as the description 5 of the invention progresses, reference being made to the accompanying drawings, showing by way of examples and in manner in a limiting sense, two forms which the invention may assume. 55 Fig, 1 illustrates in a diagrammatic and conventional manner one form of the present invention.

Fig. 2 illustrates a second form of the present invention also in a diagrammatic and conventional manner.

Referring to Fig. 1 although the presentinvention may be applied to various track layouts, it has been specifically illustrated as applied to a track switch TS which connects the rails 4 of a main track tothe rails 5 of a diverging or 10 turnout track. Track switch TS is .operated by a power driven switch machine SM which may be of any suitable type such, ior example, as disclosed in the patent to. W. K. Howe, No. 1,466,903, dated September 4, 1923. lo w The switch machine SM comprises a motor M having an armature A and a field winding F, operating contacts 6, 1, 8 and 9 and point detector contacts l0 and II. The operating contacts 6, I, 8 and 9 are controlled by motor M, contacts 1 and 9 being closed in a reverse operating circuit at all times except when the switch machine completes the movement of switch TS to its reverse position and contacts 6 and 8 are closed at all times except when the switch ma- 25 chine completes the movement of switch TS to its normal position. The point detector contacts [0, and II are employed to energize a switch position repeating relay WP of the usual polar neutral type in accordance with the extreme po- 30 sition and the locked condition of the track switch. These point detector contacts may be of any suitable type such, for example, as dis-.

closed in the patent to C. S. Bushnell, No.

1,517,236, dated November 25, 1924.

known copper oxide valve type, are connected in 45 multiple with the upper windings of relay N and R respectively, to permit the current to flow through the windings in the directions indicated by the arrow head portions of the symbols.

The energizing circuit for the switch control relays R. and N includes a winding 29 on the center core of an overload relay OL, the front contact 30 of a lock relay L and the polar contact 12 of a lever repeater relay LR. The operation of overload relay OL will be explained indetail 10 governing traffic over the switch is clear.

later in the description, it being sufficient at this time to point out that regardless of the direction of current flowing in coil 29 armature 3| will pick up and close its front contacts 32 and 33.

The normal energized lock relay L is provided to lock the circuit for the switch control relays N and R against operation whenever the switch track section is occupied or whenever a signal The circuits controlling relay L have been omitted for the sake of simplicity as they are well known to those skilled in the art and form no part of this invention.

Relays N and R are mechanically interlocked by means of three movable members or arms I5, I B and I! having at their free ends detents I8, I9 and respectively. Arm I5 is suspended from a fixed pivot 2I and normally occupies the 20 position in which it is illustrated in the drawings,

but it is arranged to at times move to the right or left in accordance with conditions to be described hereinafter. Member I6 is free to turn on a fixed pivot 22 between a lower stop 23 and an upper stop 24 and member I! is free to turn on a fixed pivot 25 between lower stop 26 and upper stop 26 Members I6 and I! are mechanically connected (not shown) to the armature of relays N and R respectively; relay N 30 being shown energized with its associated arm If in its upper position against the stop 24 and relay R being shown deenergized and its associated member I! resting on the lower stop 26. An arm 211 is loosely secured at its midpoint to arm I5 by a pivot 28 and is arranged to move in a clockwise or counter-clockwise direction in accordance with conditions that also will be described hereinafter.

In explaining the operation and function of the interlocking apparatus just described and with the interlocking apparatus in the positions shown in the drawings, it will now be assumed, merely for purposes of explaining the operation of the interlock, that relay N is denergized and relay R is energized as would result from an operation of lever SML. The relay N being slow release, as pointed out above, arm I 6 will remain for a short time in its upper position thereby allowing clearance for arm I! to move arm I5 and position it to the right as arm I "I moves towards its upper position. As arm I! completes its upward movement it contacts the left side of arm 21, moving it in a clockwise direction thereby forcing arm I6 downward, arm I6 being able to move arm I5 to the left, since at this time, arm I! has positioned its detent 28, above and out of locking position in relation to detent IS, with the result that arms I6 and I! will assume positions that are the reverse of those illustrated in the drawing. The operation involved when the relay R becomes deenergized and relay N becomes energized is merely the inverse of that just described and need not be specifically pointed out.

It will now be assumed that with the interlocking apparatus in the positions shown in the drawing, relay N is deenergized and relay R is not immediately energized as would occur upon re lease of lock relay L. Under these conditions arm I6 will release and move downwardly until its detent I9 rests on detent I8 of arm I5 thereby holding arm I! securely in its released position against stop 26, due to the added weight, and also positively, since in this position of arm I6, any force exerted by arm I! in attempting to raise, is transmitted through I8 to the-detent IB' in a direction in line with, or even actually below, fixed point 22. It is therefore evident that in order to energize relay R to pick up its front con tacts, relay N must be energized first to unlock arm ll of relay R. Also, under the reverse conditions, that is with relay R. picked up and relay N released, if relay R is deenergized for a time sufficient for its associated arm I! to release, then it is necessary for relay R to be picked up again before relay N can be operated to pick up its front contacts. In other words, this interlocking arrangement insures that after both relays have been in deenergized condition at the same time the last previously energized relay must be picked up first before the other relay can be operated.

In accordance with this invention, it is contemplated that the track adjacent to switch TS will in practice be provided with track circuits, wayside signals, line circuits and the like, constituting suitable approach locking for the switch. The specific details for such approach locking circuitsand other cooperating circuit arrangements are immaterial to the present invention and have therefore been omitted.

In the control oflice a two-position switch machine control lever SML is provided for controlling the lever repeater relay LR. The contacts of the lever SML are preferably of the snap action type so that there never will be more than a momentary interruption of the culrent flowing in the circuit for energizing relay LR due to the switching of these contacts from one position to the other.

Symbols and are employed to indicate the positive and negative terminals respectively of suitable battery or other sources of electric energy; and those terminals with which these symbols are used are presumed to have current flowing from the positive terminal designated to the negative terminal designated The symbols (B+) and (B-) are employed to indicate the positive and negative terminals respectively of suitable batteries or other source of direct current having an intermediate tap (CN) and the circuits with which these symbols are Operation With the switch track section unoccupied and with the switch lever SML in the position illustrated the various devices, relays and circuits assume positions and conditions of energization as illustrated in Fig. 1 of the drawings. Since it is assumed that the switch track section is unoccupied and all signals (not shown) governing traffic over the switch are at stop the locking relay L will be energized.

It will now be assumed that the operator moves lever SML to its reverse dotted line position. The actuation of lever SML to its reverse position closes an obvious circuit for energizing lever repeating relay LR to operate its polar contacts I2 and 34 to their reverse positions as indicated by the dotted lines. The closure of contact I2 to its reverse position completes a circuit for energizing relay R that may be traced as follows, from (CN) through asymmetric unit I3, upper coil of relay- R, coil 29 of overload relay L, front contact 3110f lock relay L, contact l2 of relay LR in its reverse position to (3-) battery; The energy flowing-in this circuit energizes relay R to close its front contacts 35 and 36 and also energizes the overload relay OL to pick up its armature 3|, as explained below, thereby closing its front contacts 32 and 33. I

- YA circuit has now been set up for operating switch machine SM to its reverse position that may be traced as follows, from battery front contact 32 of relay 0L, through the upper portion of coil 31 of relayOL, front contact 35 of relay R, lower winding of relay R, operating contacts I of switch machine SM, field F of switch machine SM, armature A of switch machine SM, operating contacts 9 of switch machine SM in its normal position, reverse wire REV, front contact 36 of relay R, front. contact 33' of relay 0L, to battery.

The operations involved in actuating the track switch from its reverse locked position to its normal locked position is merely the inverse of that just described and need not be specifically pointed out. It need only be mentioned that the return of lever SML to its normal position operates the polar contact l2 of relay LR to its right hand position to. energize the control relay N and deenergize the control relay R. With-the switch machine SMin its reverse position controller contacts 6 and 8 are closed and the switch machine is operated to its normal position through a circuit that includes the controller contacts 6 .and 8 and the front contacts 38 and 39 of control relay N.

It may be pointed out here that, while the switch machine SM is being operated to either its normal or reverse position, the switch machine operating current flows through the lower or stick winding of the corresponding control relay R or N, thus guaranteeing that the operating circuit will remain closed until the switch completes its movement.

Electric lock equivalent-In the event that the-operator actuates lever SML to a new position'while the switch control circuit is locked, as is effected by relay L being deenergized, this actuation is ineffective to condition the control circuits. With the circuits in the conditions indicated in Fig. 1 it will be assumed that relay L is dropped and that the operator actuates lever SML to its reverse position before relay L is picked up. It will be understood that relay L may be dropped by the clearing of a signal or by the occupancy of the track section as above described. Since the energizing circuits to relays N and R are open at front contact 30 of relay L, the actuation of lever SML is ineffective to control the operation of the switch machine SM.

In'the event that the switch control circuit becomes unlocked (relay L picking up) while lever SML is in its reverse position, relay R will become energized, but its. armature cannot operate to its picked up position to close its front contacts 35 and 36 due tov the fact that during the time relay L was deenergized, relay N became deenergized and its arm it dropped and locked arm I! of relay R in its released position,

all ina manner previously described. 'It is therefore necessary for the operator to restore lever SML to its normal position before control of the switch control relay R can be reestablished. This energizes relay N, and its associated arm It moves to its upper position to unlock arm ll so that the actuation now of lever SML to reverse position will effect the desired operation of relay R. r 1

Assuming the reverse condition, it is obvious that with the switch lever SML in the reverse position, if the lever SML is moved to the normal position with lock contact 36 open, the control of relay N is not effected'and after lock relay L has picked up, it is necessary first to move the lever SML back to its reverse position, to energize relay R and pick up look arm ll before the relay N will again operate in accordance with the position of the switch lever.

An out-of-correspondence lamp 0C is provided in the control ofiice for indicating by becoming lighted, when the switch machine SM is unlocked or in a position that does not correspond and a polar contact 4| and a neutral contact 42 of relay WP.

"As previously mentioned, the WP relay indicates the position and the locked condition of switch machine SM. When switch machine SM is in its-normal locked position, the WP relay is energized through a circuit that includes point detector contacts in of switch machine SM and back contact 43 of relay R, and under these conditions the contacts of relay WP will assume the positions shown in the drawings. When switch machine SM is in its reversed lock position relay WP will be energized to position its polar contact 4| to its left hand position through a circuit that includes thepoint detectors contactsll of switch machine SM and back contact 44 of relay N.

When the lever SML is moved from its normal to its reverse position, back contact 43 of relay LR will be momentarily closed and the 0C lamp will be energized through an obvious circuit and after the polar contact 34 of relay LR moves to its left hand position, the lamp 00 will remain lighted through a circuit that includes contact 4! to the left hand position at the completion of the movement of switch machine SM. It is evident that in a similar manner the 0C lamp will be energized when the lever SML is operated from'the reverse to the normal position. If the switch machine SM for any reason remains in an unlocked position or condition, as due to hand cranking operation, the switch po sition repeater relay WP will become deenerglzed and close its back contact 52, thereby energizing the lamp OC- g The overload relay 0L as'previously pointed out, operates to close its front contacts 32 and 33, thereby closing a circuit for operating the switch machine SM toeither its normal orreverse position in accordance with the position and 47 respectively. The center core 46 carries the operating winding 29 which is connected in series with the control circuit for relays N and R, and core carries a winding 3'! having a mid-tap 49, the upper portion of the winding forming a part of the circuit for operating the switch machine SM to its reverse position, and the lower portion of the winding forming a part of the circuit for operating the switch machine SM to its normal position.

The relay OL also comprises an armature 3| which underlies the pole pieces 45 and 46 and an armature 53 which underlies the pole pieces 46 and 37 Armature 3| is pivotally supported by a fixed pin 5| located under the pole piece 46 and armature 50 is supported in a similar manner by a pin 52 also located under the pole piece 46 Secured to armature 3| and 5|! and extending downwardly are two brackets 53 and 54 respectively which slidingly carry a spring supporting member 55 having two heads 55 and 51. Member 55 carries two slightly compressed springs 58 and 59, spring 58 being located between head 5? and bracket 54, and spring 59 between brackets 53 and 54.

Attached to the upper side of armature 3| by means of an insulated support 60 is a fixed contact finger GI and attached to the under side of armature 3| by means of an insulated support 62, is a fixed contact finger 63, which fingers engage fixed front contacts 32 and 33 respectively when armature 3| is in its attracted upward position as shown in the drawings.

Armature 56 is shown in its retracted position with its free end resting on a stop 64 and the armatures are so arranged that when they are both in their retracted positions, that is with armature 3| resting on stop 65 and armature 5B resting on stop 64, the air gap between armature 5D and pole piece 41 is considerably longer than the air gap between pole piece 45 and armature 3|.

It is evident that from the foregoing that, due to the magnetically favorable position of armature 3| with respect to armature 5|], when coil 29 is energized with current of one polarity or the other, armature 3| will be attracted to the position shown in the drawings to cam pins, spring 58 and the force exerted by cam pins and spring 58 against bracket 54 of armature 50 will act to hold armature 5|! firmly in its retracted position against stop 64.

As previously pointed out, when armature 3| picks up, and closes contacts 32 and 33 a circuit is completed through either the upper or lower portion of winding 3'! for operating switch machine SM to either its normal or reverse position in accordance with the position of control lever SML and the flux set up in cores 46 and 41 by the normal switch machine operating current is not sufiicient to attract armature 50 and move it from its present biased downward position, and therefore armatures 3| and 5|] remain in the positions as shown during normal switch machine operation.

However, if the current taken by the switch machine SM becomes excessive for any reason, for example, when the switch is being operated to its normal position, the greater portion of the fiux produced by the current flowing through the upper portion of winding 31 threads the cores 46 and ll in the directions indicated by the arrows and exerts a relatively large torque on armature 50 causing the armature to move from its position as shown to an extreme upward position until its free end engages pole piece 41 The upward movement of armature 50 causes a further compression of spring 58, thereby producing a force against bracket 53 to move armature 3| to its retracted position against stop 65. The release of armature 3| opens the switch machine operating circuit at contacts 32 and 33, thus removing the overload from the switch machine SM. Furthermore, with armature 50 in its attracted position, and 3| retracted, the circuit through coil 3'! on core 47 is broken, and so remains, due to the fact that armature 50 is now in the more favorable position. Thus the switch machine operating circuit will remain open until the operator moves the switch lever SML to the reverse position which will momentarily remove energy from winding 29, thereby releasing armature 55, and due to the fact that both armatures are momentarily in their retracted position, the next energization of coil 29 will pick up armature 3|.

When an overload condition takes place during a reverse operation of the switch machine SM the overload relay L will operate in a similar manner to that just described except that in this case the lower portion of the coil 31 is energized and the flux threads cores 46 and 4'! in a direction opposite to that indicated by the arrows.

Referring now to Fig. 2, in the modified form of the electric lock equivalent, arrangement here shown, switch control lever SML and its associated polar neutral repeater relay LR are similar to the corresponding lever and relay of Fig. 1 and they are arranged for the purpose of controlling a switch machine (not shown). Lock relay L at the control ofiice operates in the same manner as lock relay L of Fig. l. The switch machine and its controller and point detector contacts have been omitted to simplify the illustration, just the control wires NOR and REV and and the switch indication wires n and 1' being shown; it should be understood, however, that the switch is controlled in the same manner as in Fig. 1 to operate the track switch (not shown). The switch position repeater relay WP and the out-of-correspondence indicator 0C are similar to the corresponding WP relay and indicator OC of Fig. 1 and are controlled in a similar manner.

The modified form of the present invention further comprises a polar relay including a permanent magnet PM having oppositely disposed north and south magnetic poles designated N and S, respectively. An armature AA having a winding IE0 is fixed to a shaft ||3| and is arranged to rotate between the poles N and S, the shaft |6| being journaled at its ends in suitable fixed non-magnetic bearings H32 and ms.

Rigidly mounted on shaft |3| at the end of the shaft adjacent bearing I03 is a disc I34 and a cam disc I05. Disc N14 is provided with an arcuate slot )6 concentric with shaft H, the extremities of the slot I taper inwardly to form two cam slots H31 and H33 which are eccentric to the shaft HM and have similar faces I31 and I08 which are concentric with shaft l0! and extend towards the center of slot H36 in an undercut fashion, thereby forming two detents I59 and H0 respectively below the extremities of slot N36. The slotted portion of cam N is adapted to at all times receive a member which member is attachedto the free end of an armature N2 of a slow release magnet CR, the other end of armature ||2 being pivotally supported by a fixed pin 3.

Disc I05 is provided with twooutwardly projecting lugs H6 and III, which may be of any suitable magnetic material, such as soft iron or steel, and are secured and positioned on the cir cumference of I05 in such a manner that when it is rotated to its extreme clockwise or counterclockwise position, lugs I I6 and II! respectively' a polepiece H8 of a holding mag- I04 and I 05 to rotate in a counter-clockwise direction and when contact I I5 is positioned to the left, current of negative polarity is applied to armatureAA which causes a clockwise rotation of armature AA andits associated members I04,

and I0 5.

Due to the fact that armature AA and relay CR are simultaneously energized, armature H2 of relay CR. tends to' move upward thereby holding member I I I against theouter wall of the slotted portion of cam I04, thus permitting'the cam I04 to rotate betweenan extreme counter-clockwise position, as shown, to a corresponding extreme clockwise position in which latter position member I II will occupy the extreme'left hand portion ofslot I08.

It may be pointed out here that when energy is removed from armature winding I00, shaft I M will tend toassume a biased center position in which position the slot I06 in cam I04 will be directly belowthe relaylC R. However, cam I 04 will be unable to rotate to this biased center position due 'to the fact. that, if the armature is deenergized when,for example, the cam I04 is in the position shown in Fig. 2, armature I I2 of relay CR will release and member III will drop to occupy a position in the left hand portion of slot I01, beneath the detent I09. In asimilar manner, if armature winding AA is deenergized when ,cam' I04 .isin its extreme clockwise position, armature H2 will release andmember III willdrop to occupy the portion of slot I08 beneath detent. H0 therebypreventing cam I04 from rotating to its biased center position.

The biasing means provided for operating cam I 04 comprises a WeightIZD secured to the free endof a movablelever arm I2I, the arm being free to turn on a fixed pivot I22 thereby allowing weight I20 to be raised and lowered. Lever arm IZ-Iis connected to a hub I24 of cam I04 by means offltwo connecting arms I25 and I26 having at their lower ends slots I21 and I28 respectively which receive a fixed pin I29 located at the mid point of arm 'I2I and the upper ends of the arms are, attached to the hub I24 by means of pivots I30 and I3I respectively. Thus when cam I04 is rotated to its extreme counter-clockwise direction, as shown in the drawings, arm I25 moves upward and the bottom portion of slot I21 engages pin I29 to raise arm I2I and during this movement slot I28 in arm I26 allows arm I26 to move downward. When cam I04 is. rotatedin a clockwise direction the reverse operation takes place and arm I2I is raised by arm I26.

Two contacts I32 and I33 are arranged to be operated by the shaft IOI, these contacts being 010566.300 the rightwhen the. shaft-completes its are positioned to the right.

counter-clockwise movement and closed to the left when the shaft completes its clockwise movement. Contact I32 is provided for controlling the operation oftheswitch machineand for energizing magnet MA and contact I33 forms a part of the circuit for controllingthe operation of the switch position repeating relay WP.

Operation In the modified form of the invention, with the switch track section unoccupied and the signals at stop, theswitch lever SML and the vari ous devices, relays and circuitsassume positions and conditions of energizations as illustrated in Fig. 2 of the drawings. Since itis assumed that the switch track section is unoccupied and all sig: nals governing traffic over theswitch are at stop, the locking relay L'wlll be energized;

I It will nowbe assumed that the operator moves lever SlViL to its reverse dotted line position; The

actuation of lever SML to its reverse position closes an obvious circuit for energizing lever repeater relay LR to position its polar contact H5 to the left. This completes a circuit that .includes contact H4 of lock relay L for simultaneously applying current ofv negative polarity toarmature winding I00 and magnet CR. This energizesmagnet CR and causes armature AA to rotate in a clockwise direction which rotation will continue until member III is positioned in the extreme left handportion of slot I08 all as previously described.

When the rotary movement of shaft IN is I completed, contact I32 is closed to the left and energyis'supplied to wire REV to operatethe switch'machine to its reverse position. The-cure rent supplied to the switch machine energizes the winding of magnet MA and as previously pointed out, disc I05 hasmoved until lug H! is in contact with pole piece H0 of magnet MA, therefore, until the switch machine has operatedto open its operating circuit the shaft I0 I will be locked against its center bias, in its clockwise po-: sition by the magnetic force of pole piece H8 acting onlug H'I; '3 The operations involved inoperating the switch machine; from the reverse position to the normal position are the reverse of those just described and need notbe specifically pointed out except to state that when'shaft IOI has rotated to its extreme clockwise position contacts I32 and I33 With contact I32 positioned to the right energy is supplied through the coil of magnet MA to wire NOR to operate the switch machine .tovits reverse position and to also energize magnet MA to hold disc I05 in its clockwise position during the time the switch machine is being operated. I

Electric lock equivalentr-Assumingconditions I as shown inFig. 2, in the event thatthe operator moves the switch lever SML to the reverse position while the-switch control circuit is looked, as is efiected by relay L being deenergized, this-lever movement is ineffective to control the operation of the switch as the energizing circuit for armature winding I00 and relay CR. is-open at contact I I4 of relay:L. I

It will now-be assumed'that the switch control' circuit becomes unlocked (relay L picking up) while lever SML is in the reverse position. Underthese conditions the armature winding I00 and the relay CR will becomeenergized and ar mature AA will tend to rotate in a clockwise direction. However, due to the fact that armature winding AA and relay CR weredeenergized while the lever SML was in the normal position, member III is now occupying the extreme left portion of slot I07 under detent I09, in which position the shaft of the cam I04 is locked against a clockwise movement. It is therefore necessary for the operator to restore lever SML to the normal position before control of armature AA can be reestablished. This will unlock cam I04 by moving lll out from under [09 and to the position shown in Fig. 2, and a subsequent actuation of lever SML to its reverse position will effect the desired operation of armature AA and its associated contacts I32 and I33.

Assuming the reverse condition, it is obvious that when lever SML is moved to its normal position with lock contact H5 open, the control of armature AA is not effected and after the lock relay L has picked up, it is necessary first to move the lever back to the reverse position before the armature AA will operate in accordance with the position of the switch lever.

The out-of-correspondence lamp 0C is controlled in the same manner as is shown in Fig. 1 to indicate the locked condition of the switch machine or indicate when the switch machine is in a position that does not correspond with the position of the switch lever SML. The switch position repeating relay WP is also controlled in a similar manner except that its control circuit includes a contact H9 that is cammed to its closed position when the cam W4 is operated to either its extreme clockwise or counter-clockwise position. I

If it were not for the latch means employed, (Figs. 1 and 2) after a route, as normal, is set up, and a train has accepted it to thus drop L, the lever SML could be moved to (B) and if there were a temporary loss of shunt and L picked up, when the train is in the switch section, relay R would pick up and TS would operate to reverse, and thus change the route after it had been accepted; and possibly throw the switch under the train. As it is, such operation is ineffective,.for, due to L having been down and the switch machine having completed its stroke, N is down to lock R against picking up.

The applicant has thus shown and described two forms of the present invention in which the switch machine cannot be operated unless the switch machine control lever SML is operated at a time in which the switch machine is unlocked, namely, when the lock relay L is energized, and in the event the switch lever SML is operated to a new position when the lock relay is deenergized, the switch machine will not move to a position corresponding to the position of the lever after the lock relay L picks up.

It is to be understood that although only two specific embodiments of the present invention have been disclosed, the principles of the invention may be applied to various other types of systems and that various types of track layouts may be controlled in a similar manner without departing from the spirit of the present invention. The above ratherspecific descriptions of two forms of the present invention are given solely by way of example and are not intended in any manner whatsoever in a limiting sense. It is also to be understood that various modifications, adaptations, and alterations may be employed to meet the demands of practice without in any way departing from the scope of the present invention except as limited by the appended claims.

What I claim is:

1. In a centralized traffic controlling system for railroads; a track switch; power operated means for the switch; slow acting normal and reverse relays for controlling the power operated means; a control lever; a line circuit including a lock contact through which the lever can selectively energize the control relays; and mechanical lock means for the relays which, if both relays are released, locks down the relay that released first, and including; a pendant pivoted lock arm, a swinging pivoted arm for each relay and operable by its relay from a lower to an upper position upon the relay picking up its armature and through a path including the pendant arm and requiring movement of the pendant arm to one side, each swinging arm when in released condition above the pendant arm operating to lock the pendant arm against swinging to its side, whereby to prevent the other relay from picking up its armature.

2. In a centralized traflic controlling system for railroads; a track switch; power operated means for the switch; slow acting normal and reverse relays for controlling the power operated means; a control lever; a line circuit including a lock contact through which the lever can selectively energize the control relays; and mechanical lock means for the relays which, if both relays are released looks down the relay that released first and including; a pendant pivoted lock arm, a cross arm pivoted to the pendant arm near its upper end, a swinging pivoted arm for each relay and operable by its relay from a lower to an upper position upon its relay picking up its armature and through a path including the pendant arm and requiring movement of the pendant arm to one side, each swinging arm upon moving to its upper position operating the cross arm thereby knocking down the other swinging arm and each swinging arm when in released condition above the pendant arm operating to lock the pendant arm against swinging to its side, whereby to prevent the other relay from picking up.

3. In a centralized trafiic controlling system for railroads; a power operated track switch; a motor relay having an armature and an armature shaft, said shaft operating a cam and a switch control contact for controlling the operation of said switch; a magnet having an armature interconnected with said cam to control the rotary movement of said armature shaft; a switch control lever; a polar switch control repeater relay; a source of energy associated with a polar contact of said repeater relay; a lock relay for at times locking said switch; a line circuit including said polar contact, said armature and said magnet; said line circuit having one polarity or the other applied thereto from said source depending on the position of said lever, and said circuit including a contact on said lock relay, whereby operation of said lever causes energizetion of said magnet and said armature and rotation of said armature in accordance with the position of said lever and only while the contact of said lock relay is closed; and mechanical locking means between said armature of said magnet and said cam whereby energization of said line circuit following an opening of said line circuit by said lock relay is ineffective to operate said switch control contact unless the lever occupies the same position it occupied when said line circuit was opened.

4. In a centralized traflic controlling system for railroads; a power operated track switch; a

switch control contact for controlling the opere ation of said switch; a magnet having an armature interconnected withsaid cam to control the rotary movement of said armature shaft; a switch control lever; a polar switch control repeater relay; a source of energy associated with a polar contact of said'repeater relay; a lock relay for at times locking said switch; a line circuit connecting said polar contact,-said armature and said magnet; said circuit have one polarity or the other applied thereto from said source depending on the position of said lever, and said circuit including a contact on said lock relay, whereby operation of saidlever causes energization of said magnet and said armature and rotation of said armature in accordance with the position of said lever and only while the contact of said lock relay is closed; and mechanical locking means between said magnet armature and said cam whereby a movement of said lever to a new position after an opening of said line circuit by said lock contact is ineffective to control said switch and remains ineffective after a closure of said lock contact.

5. In a centralized traflic controlling system for railroads; a track switch; power operated means for the switch; a motor relay having an armature and an armature shaft, said shaft operating a slotted cam and a switch control contact for controlling said. power operated'means;

, a magnet having an armature with a projecting tact if the control lever is then in a new position. 1

to which it was moved while the lock contact was open.

6. In a. centralized trafiic controlling system I for railroads; a track switch; power operated means for the switch; a motor relay having an armature and an armature shaft, said shaft opcrating a slotted cam and a switch control contact for controlling said power operated means; a magnet having an armature with a projecting I ing section andprevents a rotation of said cam so long as the lock contact remains open and after said lock contact recloses if said lever is then in a new position to which it was moved while said lock contact was open.

7. In a centralized trafiic controlling system; a track section; a power operated track switch associated with said section; a normal and a reverse neutral relay for controlling the operation of said power operated switch; a lock relay for at times locking said track switch; a switch control lever; a polar switch control repeater relay; an overload relay having an operating winding and a split winding; a source of energy associated with a polar contact of said lever repeater relay; a line circuit connecting said pol'arcontact and said switch control relays, said circuit including a contact of said lock relay and the operating coil of the overload relay in series, whereby operation of said lever causes energization of one or the other of said control relays in accordance with the position of said lever and only when the lock relay is closed; a switch operating circuit including, a contact of the overload relay which is closed when the operating winding is energized, one or the other portions of the split winding in accordance with the selected control relay and a contact of the control relay selected, whereby excessive operating current causes the switch operating circuit to be broken at said contact of said overload relay.

8. In a centralized traffic controlling system; a track section; a power operated track switch associated with said section; a normal and a reverse neutral relay for controlling the operation of said power operated switch; a lock relay for at times locking said track switch; a switch control lever; a polar switch control repeater relay; an overload relay having an operating winding and a split winding; a source of energy associated with a polar contact of said lever repeater relay;-a line circuit connecting said polar contact and said switch control relays, said circuit including a contact of said lock relay and the operating coil of the overload relay in series, whereby operation of said lever causes energization of one or the other of said control relays in accordance with the position of said lever and only when the lock relay is closed; a switch operating circuit including, a contact. of the overload relay which is closed when the operating winding is energized, one or the other portions of the split winding dependent upon the control relay selected and a contact of the control relay selected, whereby excessive operating I current causes the switch operating circuit to be broken at said contact of said overload relay and remains broken until the line circuit is deenergized.

, 9. In a traffic controlling system, in combination, a track section including a track switch, power operated means for moving the switch to either of two operated positions, relay means movable to either of two efiective positions for correspondingly governing the power operated means, a control circuit for the relay means, a lever free to move at all times to either of two extreme positions to distinctively energize the control circuit and the relay means to thereby operate the track switch to its operated position,

a lock contact in the control circuit, and mechanical latch mechanism for the relay means, and including movable detent means movable to block and prevent movement of the relay means to anew effective position in response to energization over the control circuit if, between a movement of the lever from a former extreme position to the other extreme position, there has occurred an opening, and a subsequent closing, of the control circuit by the lock contact,

10. Ina centralized trafiic controlling system; a track section having a power operated track switch; a normal and a reverse neutral relay for controlling the operation of said power operated switch; a lock'relay for at times locking said track switch against operation; a switch control lever; an overload relay having an operating winding and a splitwinding and a front contact; a source of energy associated with said lever repeater relay; a line circuitconnecting said lever and said switch control relays, said circuit including a contact of said lock relay and the operating coil of the overload relay in series, whereby operation of said lever causes energization of the overload relay and one or the other of said control relays in accordance with the position of said lever and only when the lock relay is closed; a switch operating circuit including, the contact of the overload relay, one or the other portions of the split winding in accordance with the selected control relay, and a contact of the control relay selected, the portions of the split winding, when energized, being arranged to tend to open the front contact of the overload relay, whereby excessive operating current causes the switch operating circuit to be broken at said contact of said overload relay.

11. In a centralized traffic controlling system for railroads; a power operated track switch; a normal and a reverse slow acting neutral relay for controlling the operation of said power operated switch; a lock relay for at times locking said track switch; a switch control lever; a source of energy associated with the lever; a line circuit connecting said lever and said neutral switch control relays; said circuit having one polarity or the other applied thereto from said source depending on the position of said lever, and said circuit including a contact on said lock relay, whereby operation of said lever causes energization of one or the other of said switch control relays in accordance with the position of said lever and only while the contact of said lock relay is closed; and mechanical interlocking means associated with said neutral control relays and including a latch freely movable unless blocked, a blocking means associated with, and operable by, each neutral relay, and each movable, upon release of its relay prior to the picking up of the other relay, to block movement of the latch and thereby prevent the picking up of the other relay, whereby control of the operation of said switch to a new position by said lever first requires correspondence between the last previously energized control relay and said control lever following each opening of said line circuit and subsequent closing thereof by said lock relay.

12. In a centralized trafic controlling system for railroads; a power operated track switch; a normal and a reverse neutral relay for controlling the operation of said power operated switch; a lock relay which, if deenergized, deenergizes both said neutral relays; a switch con trol lever for selectively energizing said neutral relays through a line circuit whereby operation of said lever causes energization of one or the other of said switch control relays in accordance with the position of said lever and only while said lock relay is energized; and mechanical interlocking means associated with said neutral control relays and including a normally freely movable latch, a blocking means controlled, re-

spectively, by each neutral relay and each positionable, by its relay operation, at times, to block movement of the latch so as to prevent movement of the other blocking means and thereby the picking up of the other neutral relay despite the energization of such neutral relay.

13. In a traffic controlling system, in combination, a track section including a track switch, power operated means for moving the switch to either of two operated positions, translating means movable to either of two efiective positions for correspondingly governing the power operated means, a control circuit for the translating means, a lever free to move at all times to either of two extreme positions to distinctively energize the control circuit and the translating means to thereby operate the track switch to its operated position, a lock contact in the control circuit, and mechanical latch mechanism for the translating means, and including movable detent means movable to block and prevent movement of the translating means to a new effective position in response to energization over the control circuit if, between a movement of the lever from a former extreme position to the other extreme position, there has occurred an opening, and a subsequent closing, of the control circuit by the lock contact.

14. In a centralized traiiic controlling system; a track section including a power operated track switch; a control lever for the switch; a polar lever repeater relay having a polar contact and a source of energy associated therewith; a lock relay for at times locking said switch against operation; a control circuit for controlling said switch, said circuit including a contact of said lock relay and energizable with one polarity of current or the other in accordance with the position of said lever repeater relay; relay means distinctively responsive to the polarity of current in said control circuit to normally move so as to cause distinctive operation of said switch, and mechanical locking means for at times locking said relay means against response to current in said control circuit, and including, latch means positionable to prevent said relay means response and normally freely movable to permit the response of the relay means to current in the control circuit, and a plurality of blocking means associated with the relay means and efiective to prevent movement of the latch and thereby of the relay means upon movement of the lever to a new operative position after said control circuit is opened by the lock relay contact and remains so effective until the lock relay contact closes the control circuit and the lever is returned to its old position.

15.. In a centralized trafiic controlling system, in combination, a track section including a track switch, power operated means for operating the switch, a control circuit for the power operated means, a lock contact in the control circuit, a two position lever for selectively energizing the control circuit, translating means movably responsive to the energization of the control circuit to make the control circuit effective to energize the power operated means, and mechanical lock means for locking the translating means against response to energization, and including, latch means normally freely movable, blocking means controlled by the translating means to a position to retain the latch means in a position to prevent the response of the translating means to the energization of the control circuit, unless the lever is moved from a position where it is in correspondence with the track switch.

FRANK X. REES.

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