US1584227A

US1584227A - Train control

Info

Publication number: US1584227A
Application number: US596075A
Authority: US
Inventors: Winthrop K Howe
Original assignee: General Railway Signal Co
Current assignee: SPX Corp
Priority date: 1922-10-21
Filing date: 1922-10-21
Publication date: 1926-05-11
Anticipated expiration: 1943-05-11

Description

May 11. 1926..

W. K. HOWE TRAIN CONTROL Filed Oct. 21, 1922 VENTOR f. ff mza jiTToRNEY 5 I Eh.

Patented May 11, 192%.

wmrnnor K. now-n; or ROCHESTER, new assreii'cn-rouennnnan RAILWAY SIGNAL CGMIEANY, 0F GATES NEw 'i" TRAIN CONTROL;

Application filed. Gotober 2-1, 1922. $eria1 No. 596,075.

This invention relates to automatictrain speed control systems for railroads.

Broadly considered, this invention contemplatesthe provision of automatic equipment on the trackway and on a train for enforcing predetermined speed limitations, which the train can not exceed .xvithout an automatic brake application, at various points in the travel ot the train, such as in a .cautionblock, it being more particularly desired to provide anequipment of this character which Will permit any desiredspeed limitv to beset up a-t any desired point as required by a simple adaptation of the trackivay equipment. More specifically, the invention involves the use of pairs of influence devices on the tr ack'l'ocated at the appropriate control points, the spacing or distance apart of the elements of each'pair dete mining the limiting speed for trains at that location. Inasmuch as tratiic conditions ahead of a train in a block may change at any time While the train is in thatblock, it is considered desirableto make provisions to automatically remove the limitations inrposed uponthe movement of the train by a pair. of track devices at the next pair of track devices encountered by the train, set ting upit necessary at the second pair a new restriction upon the movement of the train. Inother Words, it is thought to be important in speed control systems of the type imposingspeed limitations from point to point to governthe train step-by-step, S0 to speak, from point to po nt, so that the train may be released from the dominance of the automatic system at each control point.

To carry out this principle or idea of step-by-step control above indicated, it is proposed in accordance with this invention to make the first track element of each pair permanently etl ective to influence the apparatus on a passing car. to construct the carcarried apparatus so that it Will be automatically restored to normal by such permanently active track element, and to make the speed restrictions automatically enforced at each pair of track elements dependent notonly On traflic conditions but also upon the spacing of the particular pair of elements, so that any'desired speed limit may be set up at any selected point by separating or spacingthe elements of a pair accordingly.

In one specific embodiment of the invention herein disclosed, the desired speed limits at the respective control pointsareentorced in accordance wth the time-distance interval principle, that is, the carapparatus acts'to automatically apply the brakes at each pair of track elements it the car traverses the space between this pair of elements in'less than a PTBClQtBTHllHQd interval of time measured by a time-controlled or time-element device on the car. In this type of: system, it an automatic brake application is produced at a'pair of track elenients'due to excessive speed at that point, it is desirable to. permit the release of the brakes at the next pair 'ot track elements, either because the-engineer has been particularly diligent in stopping the train, or because traffic conditions ahead in the meantime have cleared upand make further action ot the brakes unnecessary. This desired end isaccomplished according to the specific embodiment of the invention disclosed by automatically restoring the brake-setting or control means: at the 'i'irst track element of each pair, permitting the engineer to release the brakes, unless the speed of the train at this succeeding pair is too high for safety and traffic conditionsfin advance still require continued'reduction in speed.

Various other characteristic features of the invention, its advantages, and adaptabilities to practical operating"conditions will be pointed out hereinafter as thedescription 01 one specific embodiment thereof progrosses.

In the accompanying -draWing,.Figure l is a diagrammatic view showing the trackvvay devices and circuits according to this invention Fig. 2 illustrates in a simplified and con ventional manner carcarried devices and circuits of this invention, and also a pair of track elements or inductors to illustrate their cooperation with the carv apparatus; and

Fig. 3 is an. enlarged sectional view of the clutch F shown inFig. 2. I

In the embodiment of the invention illustrated, the transmission of the desired control influences to limit the speed at several points in a block is produced by track elements which are governed in accordance with traiiic conditions ahead. Various arrangements of trackivay circuits suitable for the purpose of. controlling these track elements may beemployed, and it should be understood that the arrangement shown in Fig. 1 is only a typical example. Referring to Figure 1, the track rails 1 of the railroad track are divided by insulated joints 2 into blocks in the usual way, on block I with the adjacent ends of two other blocks H and J being shown. The parts and circuits associated with the various blocks are the same, and for convenience will be given like reference characters with distinctive exponents.

Each of the blocks is provided with a track battery 3 and a track relay 4, the same as in ordinary block signal systems. This invention is preferably used in connection with the ordinary block signals, either of thetwo or three-position semaphore type, position light signals, distinctive aspect color-light signals, or the like. For convenience fined semaphore signals Z have been shown conventionally without attempting to illustrate their well-known control circuits and devices.

In each block are provided pairs of track elements T and t at the several points in the block at which the speed of the. train is to be checked. the spacing between the elements T and t of each )air determining the distance a train is permitted to run in a predetermined time at this point in the block. In the specific embodiment illustrated, these track elements are shown on the right side of the track when facing in the normal direction of trailic, as indicated by the arrow. Each of these track elements T and t com-- prises a U-shaped iron core 5 terminating in enlarged pole pieces 6, the back yoke of the core 5 of the track element It being provided with a coil 7. The cores 5 are preferably made of a good quality of laminated sheet iron, similar to that used in transformer construction, in order to reduce the eddy current loss, produced by a change of flux through the core, to a minimum. At each point of location of a pair of track elements T and t is located a repeater track or line relay 8, these relays 8 being connected in multiple between the line wire 9 and a common return wire C (not shown), and are energized when the track relay l of the block in advance is energized.

The energizing circuit for the repeater track relays 8 of the block I may be traced as follows:beginning at the terminal B of a suitable source of energy such a battery, wire 10, front contact 11 of the track relay line wire 9, lead-in wire 12 to each of the repeater track relays 8, lead-out wire 13 leading from each relay back to the common return wire C connected to the other terminal of this source of current.

From this circuit it is apparent that when the track relay of the block in advance is energized that each of the repeater track relays 8 will likewise be energized, thus closing their front contacts 14. .These front contacts 14 when closed close the coil 7 of each of the respective track elements it in a circuit'preferably of low resistance, thereby causing them to function in a manner as will be explained hereinafter. The track apparatus at each control point in a block is the same, except for the spacing between the elements of each pair, and for convenience these pairs of elements have been designated with the same reference character having distinctive alphabetical exponents.

The car-carried apparatus of one specific embodiment of this invention has been illusrated in Fig. 2, and comprises suitable devices which will first be separately de scribed. One of these devices comprisesan influence receiving car element- L consisting of a ll-sh-aped core 15, preferably constructed of laminated transformer iron, and terminating in enlarged pole pieces 16. The leading leg of the U-shaped core of the car element L is provided with a primary coil P, whereas the other leg is provided with a secondary coil S. These car elements L are preferably mounted directly on the truck of the railway vehic e, and are protected from excessive jars and vibration, and from the weather in any suitable manner. The specific construction of the mounting of this car element L is not within the scope of the present invention, and therefore has not bee illustrated in detail.

The car-carried apparatus includes a control relay CR, a repeater relay RR and a check relay CK. Although these relays have been shown substantially identical, this illustration is merely conventional, and in practice the control relay CR will be constructed to be more sensitive and will be provided with much smaller movin parts and con tacts than the other relays, and will therefore function on a smaller change of energy. The repeater relay ER is preferably of a slow acting type, and has been shown cenventionally as a retarded relay. This relay RE is also provided with special contacts for controlling several circuits in a manner so that at least one of these circuits will be closed at the relay at all times, which will for convenience be referred to as a maltebeforebreak contact hereinafter. Each of these relays have their moving parts well balanced so that they will not be affected bv jars and vibration, and are preferably mounted in a comparatively heavy spring supported relay casing, whereby the ars and vibration will to a certain extent be absorbed and transformed before reaching the relays. thereby minimizing their effect to produce improper operation of these relays.

The car-carried apparatus also includes a train control device K which has been illustrated as an electro-pneumatic valve. This train control device may control the train in any suitable manner as, for instance, by aclSO Losses? tuating the usual engineers valve in a manpipe to a predetermined extent only, for rea-.

sons well known to those skilled in the art, and is also preferably constructed so that if automatically actuated to its normal condition the brakes will not be automatically released, but will merely permit the engineer to again release the brakes. This latter feature is desirable because if the engineer should be disabled, asleep or not attending to his duties for some other reason, a single automatic actuation of the train control device K will assure stoppage of the train. This train control device K is of the normally energized type, and has its normally energized circuit completed through the contacts 1S controlled by the armature of its electro-magnet. lherefore, a momentary deenergization of the train control device K will permanently deenergize it, because its energizing circuit will be interrupted permanently by its front contact 18.

Another element of the car-carried apparatus embodying this invention comprises a time element or time'controlled device TC. This time controlled device TC is provided to normally close an auxiliary circuit, to open this circuit a very short period after the device has been initiated, to maintain this circuit open for a predetermined time, and then again close said circuit. This time element device TC may take any one of a variety of forms, and may employ. any one of the well-known principles for measuring time. For instance, it may ineludewellknown clock mechanism, or it may be constructed to measure an interval of time by the escape of fluid through an orifice, or the like. For convenience, this time controlled device TC has been illustrated as a mechanism operated by a motor M, which is pref.- erably of the type that will maintain a con? stant speed irrespective of a slight variation in the voltage of the source of E. M. F. illustrated as a battery 20. This motor M is pro-. vided with an armature having a commutafor 21 cooperating with brushes 22, and having a field winding 23 preferably connected in multiple with the armature 21, this field winding and armature being connected across the battery 20. The constant speed operating characteristic of this motor may 3e obtained to a large extent by proper design, and if desired, a suitable speed controlling regulator may be incorporated therewith to give this motor a constant speed characteristic.

The motor M through the shaft 24 drives the housing of a friction clutch F, the other member 19 of said friction clutch being rigidly connected to a shaft 25 provided with a worm 26, and the housing F and member 19 are preferably spring pressed toward each other against an intervening friction disk, by a spring 17. The construction of this friction clutch is preferably such that a predetermined torque may be transmitted from the shaft 2% to 25, but if a higher torque is attempted to be-transmitted this clutch will slip, the clutch being preferably so designed that such slippage thereof will not produce detrimental heating of the friction surfaces.

The Worm 26 of the shaft 25 is in continuous operative engagement with a worm wheel 27, which has fastened thereto in any suitable manner a disk 28 which is provided with a contact sector 29 insulated therefrom by insulation 30. As the worm wheel 27 and the disk 28 are rotated in the direction of the arrow by the motor M through the intervening friction clutch F, this worm wheel and disk will be stopped by the projection 31 of the disk'28 coming in' contact with the extension 82 of the armature A of the time starting or holding magnet GS. With the disk 28 in this position, the contact sector 29 will bridge the stationary contacts 33 and 84. If new the time starting magnet CS is for any reason deenergized, the disk 28 will be rotated in the direction of the arrow through the action of the friction clutch F until the projection 31 of this disk is stopped by the other extension 35 on the armature A. The arrangement of parts is such that if the projection 31 is stopped by the extension 85, the stationary contacts 33 and 34 will not be bridged by the contact sector .29.

An auxiliary checking device to check the continual rotation of the motor M is pro- 1 vided. This device is of the Well known centrifugal type, and comprises a collar 10 rigidly fastened to the shaft 24, a collar 41 slidably mounted on thisshaft and biased from the other collar 40 bya spring 42. Two pairs of links 43 are provided to coin nect these collars. These links are pivotall-y connected together and have connected thereto at the junction of these links cc trifugal weights 4%, whereby the rotation of the shaft 2a causes the weights at to compress the spring 4-2 and shift the collar 41 along the shaft 24-. The collar 4C1 has connected thereto but insulated therefrom a contact disk t5. If the motor is rotating the shaft 2% at or above the predetermined speed, this contact disk to will be in a position to bridge contacts 46 and 17 conventionally illustrated by arrows.

A reset switch BS is preferably provided 1 in order to enable the engineer to release the brakes after an automatic brake application has occurred, so that he may again proceed, if his train should happen to be stopped'between pairs of track elements.

lit)

In order that the engineerbe unable to reset the automatic train control apparatus back to its inetlective condition while the train is being slowed down, this reset switch is preferably n'iounted on the railway vehicle so that it is only accessible from the ground. As will appear hereinafter, this switch acts to reset the car-carried apparatus back to its inactive condition if this reset switch is momentarily operated Operatiow-rtssume that a railway vehicle is traveling equipped with the car-carried apparatus in its normal condition, that is, that this vehicle is moving between control points in a block when the next block in advance is clear. Under these conditions, certain of the circuits will be energized from a suitable source of energy, and in order to simplify the illustration of these circuits the letter B has been used to designate one terminal of a suitable source of E. M. F, whereas the letter C has been used to represent a common return wire leading to the other terminal of said source.

The circuit for normally ei'iergizing the control relay CR may be traced as follows beginning at the terminal B of a suitable source of energy, preferably a battery, wire 50, front contact 51 of the control relay CR,

wires

52 and 53, winding of the control relay CR, wire 5 the blade of the reset switch RS, wire secondary coil S of the car element L, wire 56 back to the common return wire C.

The primary coil P will be energized through a circuit which may be traced as follows :beginning at the terminal B oi": said source of E. M. F., wire 57, winding of the check relay CK, wire 58, primary coil P of the car element L, wire 59 back to the common return wire 0.

With the control relay GR in its energized condition, a circuit for the repeater relay will be completed which may be traced as follows :beginning at the terminal B of said source of E. M. F., wire 50, front con tact 60 of the control relay CR, wire 61, winding of the repeater relay RR, wire 62 back to the common return wire C.

l Vith the repeater relay BB in its energized condition, a circuit for the time starting magnet GS of the time controlled device TC will be completed, which may be traced as follows :beginning at the terminal B of the battery, wire 63, contact 64 of the repeater relay RR, wire 65, winding of the time starting magnet CS, wire 66 back to the common return wire C Another circuit will be closed when the repeater relay ER is energized, which may be traced as follows :beginning at the terminal B of the battery, wire 63, make-before-break contact 67, wire 68, stick contact 18 of the train control device K, wires 69 and 70, front contact 71 of the check relay element L. The magneto-motive-force produced in the car element L is mainly due to the primary coil P, because the current :tiowing in the secondary coil S is very small, it being only sufficient to maintain the sensitive control relay CR energized.

lVitha railway vehicle equipped with this car apparatus in its normal condition, as just described, let us assume the vehicle to pass a track element in the active stopping condition, say track element T. As the car element L passes over the track element T,

the reluctance of the magnetic circuit includ ing the core 15 of the car element is momentarily reduced. This change in reluctance causes a. sudden increase of flux and then a decrease its normal condition, partly due to a diversion of flux from leakage paths, and partly due to an increase in the total flux through the primary coil P. This sudden increase and decrease of flux through the secondary coil S induces a voltage therein, similar to that of a single cycle of al ternating current E. M. F. The secondary winding S is so connected with respect to the battery that the first wave of the unicycle of E. M. F. opposes the voltage of the battery, thereby reducing the energizing current of the control relay OR to an extent to cause its armature to assume the deenergized position by the action of the spring? Since the control relay CE is connected in a stick circuit, it will be permanently deenergized until picked up by some other means.

The deenergization of the control relay CR interrupts the energizing circuit for the repeater relay RR, thus causing its armature to assume its deenergized position by the action of the spring 7 6, thereby closing an auxiliary circuit for the train control de vice K shortly after which the main circuit for this train control device K will be broken, this overlapped circuit closing tea ture of the repeater relay RR being due to the construction of the n'iake-betore-break contact 67 and is obvious from the construction of this switch as illustrated.

This auxiliary circuit for the train control device K may be traced as tollowszbeginning at the terminal B of a battery, wire 63, make-before-break contact 67, wire 78, stationary contact 38, contact sector 29, stationary contact at of the time control device TC, wire 79, stationary contact l7 contact dish and stationary contact 4.6 of the centrifugal device, wi cs 80 and 70, front contact 71, of the check relay CK, wire 72, winding of the train control device K, wire 73 back to the common return wire G.

fil'inr'iltansously with the energization of the auxiliary circuit anl the deenergization 01 the main circuit of the train control device hi, the time starting magnet GS of the tine controlled, device TC will be deenergized, thereby causing the armature A to assume its deenergized position and tree the projection 31 from the extension of this armature, thereby allowing the disk 28 to start in rotation in the direction of the arrow.

The deenergization of the repeater relay completes a pickup circuit for the control relay CR, which may be traced as follows: beginning at the terminal B of a battery, wire 63, contact (is of the repeater relay RR,

wires

81 and 53, winding oi the control relay CR, wire at, blade of the reset switch RS, wire 55, secondary coil S of the car element- L, wire 56 bacl: to the common ,return wire C. The completion of this pickup circuit causes the control relay OR to pick up and again close its stick circuit, as heretofore traced. This energization of the control relay CR again energizes the repeater relay RR, and recloses the main circuit for the train control device K. The parts are arranged so that this main circuit is again closed before the disk 28 has rotated far enough to cause the contact sec-- tor 29 to interrupt the circuit completed thereby. it should be noted that the time starting magnet CS has been again energized by the contact 6% of the repeater relay RR; and the parts are back in the normal position except that the disk 28 is now making its cycle of rotation in the direction of the arrow, and after a partial revolution has opened another break in the auxiliary circuit of the train control device at conta ts 33 and'Sa without any ct fee-t upon the device K at this time.

It is thus seen that a single inductive influence transmitted from the trackway merely initiates the cycle of operation of the time element device TC and does not deenergize the train control device K, and interfere with the operation of the train.

Let us assume now that the train is entering the block I under clear traliic conditions ahead, and that it has passed by the track element 1 which has caused the time con trol device to be started upon its cycle of operation. The passage or the car element L over the track element 25 will, however, not

- interfere with the movement of the train because this track element 25 is then in its in.- active or ineffective condition, because the coil 7 ct this track element is closed in a circuit of low resistance. This result is due to the fact that as the car element L passes over the tract: element 6, only a very small voltage will be induced in the secondary coil S or this car element. One ground of reasoning my which this slight induction of voltage may be accounted for is based on the theory that a closed winding in a variable flux field will produce a demagnetizing action. over the tracl: element t a change of flux is produced in this track element which induces a comparatively large current in the. close-circuited coil 7 on the back yoke of this track element, this current by well known laws of induction being); in a direction to prevent a further increase of flux through this track element. Since this track element 25' to a certain extent prevents a further increase of flux therethrough, the reluctance of the magnetic circuit including the car'element L will not be materially reduced, and therefore a very small voltage only will be induced in the secondary coil S which isinsufiicient to actuate control relay Cl Since the second track element has been shown to be ineffective under clear traliic conditions, only one inductive influence is transmitted at each control point and the train may pass'throug'h a clear block unrestricted in its movement.

Let us assume now that the railway vehicle in question is entering the block 1 minor caution traffic conditions, that is, when the block J is occupied by another train. The presence of the train in the block J shunts the track relay al thereby deenergizing it and cutting oil energy from the line wire 9, thereby deenergizing each of the repeater track relays 8. This deenergization of the track relays 8 opens the circuit for each of the coils 7 of the track elements If, t and t Let us assume that the car element L has passed over the track element T, and that the time control device TC has been initiated upon its cycle of operation. First, suppose the speed is too high and the vehicle will 1 pass by the track element t before the predetermined time to be measured by this time controlled device TC has expired, that is, before the time control device TC has returned to its normal position. As the car element L passes over the track element 1? with its coil 7 open-circuited, acontrol influence will be transmitted to the control relay CE.- in the same manner as heretofore explained in connection with the track ele- 1 ment T, thereby deenergizing this control relay OR. The deene-rgization of the con ,trol relay CR deenergizes the repeater relay RR, thereby closing at its back contact a break in. the auxiliary circuit for the train That is, as the car element passes control device K and opening the main circuit of this train control device. The closure of this break in the auxiliary circuit for the train control device K at this time does nothing toward energizing this train control device, because this circuit is open between the stationary contacts 33 and 34. (disk 28 not havingreached its normal position) and thereforethe train control device K will be deenergized, and the brakes Will be applied in a n anner heretofore explained. The. decncrgization of the repeater relay RR will again pick up the control relay CR through the pickup Wire 81 as heretofore exolained, thereby again causing repeater relay HR to be energized, Which in turn will again energize the time starting magnet GS of the time controlled device TC, whereby the disk 28 of the time controlled device will again be stopped in its normal position. The train control device K remains deenergized because relay ER is picked up and the main energizing circuit for device K is broken at its own contacts 18.

Second, suppose that the speed of the train is less than that prescribed by the spacing of the track element T and 25. Under these conditions, the disk 28 will have returned to normal position before the second impulse is received from the second track element t; and since the auxiliary energizing circuit for the device K is thus closed at contacts 33 and 3% at the time the relay RR drops, the device K is kept energized and the only result is to startthe disk 28 on another cycle of operation,

Considering 110W the case Where the brakes are automatically applied at the pair of track element-s T and t on account out excessive speed, the train will. of course be slowed down and if it is possible for the train to reach a speed at the next pair of elements T and t lower than prescribed by the spacing of these elements, it is evident that it would be safe and proper to permit the release ot' the brakes. Similarly, the block J may become unoccupied by the time the train in question, after passing the pair of track elements T and t, reaches the pair of track elements T and t; and in this case also it is safe and proper to permit the release of the brakes irrespective of the speed 01 the train at the time. In any event, it is contemplated in this invention to restore the train control device K at the next pair of elements, as T and t, and thereafter, it necessary, to cause another opera tion of the device K.

To make clear this automatic restoration of the device K, imagine the train, with device K deenergized and the brakes acting, is continuing its travel and passes over the track element T. This Will deenergize the control relay GR in the same manner as hereto- .fore explained in connection with the track clement T. The deenergization of the control relay CR deenergizes the repeater relay RE, which in turn deenergizes the time starting magnet CS and allows the disk 28 to start upon its cycle of rotation. Before the contact sector 29 breaks the shunt between the stationary contacts 33 and 34;, the auxiliary circuit for the train control device K will be completed by the back portion of the make-before-bieak contact 67 of the repeater relay RR, thus causing the train control device K to be energized. The enen gization of the train control device K causes the back contact 18 thereof to close the stick circuit at this point, and as the repeater relay BB is again energized for reasons heretofore explained, the train control device K will be energized through this stick circuit. It is thus seen that, if the train is approaching a control point with the train control device K deenergized, this device K will again be energized when a single active track element is passed over.

Let us assume now that the train is passing from the track element T to the track element z with the brakes acting because the previous control point Was passed at excessive speed, and that the speed is still higher than the permissive speed prescribed by the spacing of these elements. Under these conditions, a control influence will be transmitted inductively from the track element t to the control relay CR before the disk 28 of the time control device TC gets back to its normal position, and therefore the train control device K Will again be deenergized in the same manner as it did when passing from the track element T to the track element 25 in less than the required time, as heretofore described. The energize.- tion of the train control device K occurring at the track element T will, therefore, be only momentary if the speed is still excessive and will not materially affect the airbrake system of the train or permit release of the brakes because of the short time during which this device K is actually energized.

If it should happen that the block J is clear at the time the train passes the track element 25, the device K will not be deenergized, as just described, because the element 6 will then have its coil 7 included in a circuit of low resistance and will not cause dropping of relay CR.

If the speed of the train at the elements T and t is lower than that prescribed by these elements, the device K remains energized, and remembering it is being assumed that a brake application "as made at the element T and t, the engineer may release the brakes.

It may happen that the train, after an automatic application of the brakes, csoecially at the elements T and 15", will be F 1 decreases stopped before it reaches" the first track element of'the next pair, as T, and can not obtain thereat an automatic restoration of the device K. In order that the engineer may again proceed under these circumstances, he Will be required to operate the resetswitch RS which is only accessible from the ground, as heretofore mentioned. The engi'neer IIOW momentarily breaking the circuit of the control relay CR, by actuating this reset switch RS, causes the control relay CR to be dee'nergiz e'd, thereby causing the several devices and the time controlled device TC to be actuated in the same mannor as if this control relay had been automatically actuated by an inductive control influence. Among other things restoring the device K and maintaining it energized, because of the momentary deenergi'zation of the repeater rfelay Rlhcauses the train con trol device K to be picked up by the completion ofthe auxiliary circuit, and it Will then be maintained energized through its stick circuit similar to th'epicking up of this train control device K when passing over the track element T in the ope "ation heretofore described.

The engineer can not carelessly leave the reset switch RS open or maliciously fasten it open, because the device K will be deenergized upon so doing, due to the opening of contacts 83 and 34:, the relays CR and RR be ing deenergized.

It is thus seen that, if a car equipped with the apparatus illustrated passes over two successive active track elements in less than a predetermined time measured by the time controlled device TC, the train control device K will be deenergized. After this device K has been thus deenerg'ized and the .train passes over a succeeding pair of active track elements, first in less than said predetermined time at excessive speed), thetrain control device K will he only momentarily energized; second, in more than said time (safe speed) the device K is energized and kept energized. Also, if the second element of said succeeding; pair is in an inactive condition, due to the clearing up of the block ahead, then the device K is energized and kept energized irrespective of the speed.

T he check relay CK has been provided so that the train control device K Will be deen' ergized when the reduction in the exciting current flowing through the primary coil P is beloiv that necessary to produce the necessary magnetomotive-force for transmitting a control influence to the control relay CR, either due to a break in this energizing circuit, the depreciation of the battery or other source of current, or the like. The check relay CK is so designed that it will release its front contact 71 when the current flowing: therethrough and through the prin'rary coil belo'u 'the necessaryvalue just referred to, thus dee'nergi'zin-g the train control device K and bringing then-aim to a stop:- This check r'elayCK thus assures the stoppage of the train if there not sufficient magneto-motive-force in the car element L,

and the engineer ivould be required to oper ate a suitable cut-out device (not shown) for cutting out all of the automatic control apparatus under this condition.

Let us assume that another break in the automatic control apparatus takes place,

namely, the energizing circuit for the time starting magnet GS, either due to a failure to make contact at the front contact 6a of the repeater relay ER because the Winding of this relay is shorted, or because there is a permanent break in this circuit. The deenergization of this time starting magnet CS will allow the disk 28 to rotate in the direction of the arrow until the projection 31 strikes the extension on the armature A of this time starting magnet. With the disk 28 in this position the contact sector .29 will not bridge the stationary contacts 33 and 34, and consequently 'When the first control influence is transmitted after this break has occurred the-train control device K Will be permanently deenergized due to this permanentbreak in the auxiliary energizing ci-rcuit for this train control device K. Ob viously, the train control device K will be deenergized if the repeater relay RR or the control relay CR should fail and be permanently deenergized. It is thus seen that the failure of any of the'circuits shown in the car-carried apparatus as Well as along the tnckway function-in a manner so that circuit failure will cause an automatic brake application.

Let us assume now that for some reason the motor M discontinues to operate, either reducing its speed beloiv the predetermined speed heretofore mentioned, or discontinues to operate altogether, either due to failure of the motor itself or due to the failure of energy for o-peratin-g the same. This de crease in the speed of the shaft 24; causes the spring L2 to shift the collar 41 and con.- tact disk l connected thereto to the right because of the decrease of centrifugal force acting: on the Weights i l. This shifting of the disk 45 provides another break in the auxiliary circuit for the train control device K, so that upon the reception of a control influence thereafter, the train control device K will be aei manently deenergize'd in a similar manner, as explained when this circuit is permanently opened at the contacts 3 and 3d.

In order to explain the nature ofj'th-e invention, and the functions and modes of operation of the means constituting this invention, there has been shown and deribed one typical embodiment "thereof hiclrha's'beeii selected-moment a new of facilitating explanation of the invention, than for the purpose of disclosing the specific structure and arrangement of parts and circuits preferably employed in practice; and it should be understood that various adaptations, modifications and additions may be made to this particular disclosure without departing trom the invention. For example, it is contemplated that the system may be used in conjunction with any suitable or well-known type of block signal system, either of the direct or alter nating current type, and that various forms of mechanism for controlling the application of the brakes and the supply of propelling power may be used and governed the same way as the train control device K, such control mechanism being of course designed to efi'ect an automatic brake application that can not be forestalled or prevented by the engineer, and in a manner conforming with recognized air brake practice.

Other deviations from the specific disclosure will be evident to those skilled in the art, and it should be understood that the specific structure shown and described is merely illustrative of the invention, and does not exhaust the various embodiments thereof.

What is desired to be secured by Letters Patent of the United States, is

1. In a train control system, the co1nbination of car-carried means comprising; a cyclic device adapted to be initiated by a control influence transmitted from the trackway which will restrict the speed of the train it a second control influence is receive-d from the trackway before its cycle of operation has been completed, and which will remove said'restriction if said cyclic device is again initiated but no second influence is received during the second cycle or" operation; and trackway means comprising pairs of influence transmitting devices spaced to enforce dilferentspeed restrictions, the first trackway device of each pair being permanently active whereby said first trackway device will act to remove such speed restriction under clear trafic conditions ahead.

2. An automatic train control system comprising, pairs of influence transmitting devices located along the trackway and spaced to correspond to predetermined speed limits to be enforced and in which one device of each pair is permanently active, and and car-carried apparatus including a cyclic device which will enforce a speed limit corresponding to the spacing of each active pair of trackway devices and remove previous restrictions in the movement of the vehicle upon passing a pair of trackway devices of which only one is active.

3. In an automatic train control system, the combination of pairs of trackway devices along the trackway, the first of which is permanently active, and of car-carried apparatus adapted to cooperate therewith to set up a predetermined speed restriction when passing a pair of trackway devices dependent upon the spacing of these devices and to remove any restriction previously enforced when passing over the first device of a following pair of trackway devices.

4. An automatic speed control system for railways comprising, a brake control device, and means partly on the vehicle and partly along the track for actuating said brake control device if a predetermined distance along the trackway is traversed in less than a predetern'iined interval of time and for restoring said brake control device to normal if more than a certain other predetermined period or" time is consumed while traversing a following predetermined distance.

5. In an automatic speed control system for railways, the combination or" a car-carried apparatus which if actuated applies the brakes of a railway vehicle automatically and means partly on the vehicle and partly along the track for actuating said apparatus it a predetermined distance at a control point is traversed in less than a predetermined time under caution tratlic conditions and for restoring said apparatus to normal when a following control point is passed under clear trafiic conditions.

6. In an automatic speed control system for railways, the combination of car-carried apparatus including a device for applying the brakes of a vehicle automatically when actuated means for actuating said device if two successive control influences are received in less than a predetermined time and for restoring said device to normal it only one control influence is received in said period of time, influence transmitting devices located in pairs at control points along the trackway spaced to enforce a predetermined speed limit at each control point, and means for automatically controlling one device of each pair in accordance with traffic conditions ahead.

7. An automatic speed control system for railways comprising, means on the vehicle for applying the brakes, means for actuating said brake control means it two successive control influences are received from the trackway in less than a predetermined time and for automatically restoring it to normal it a single control influence is received in a similar predetermined interval of time, and devices along the trackway for transmitting the desired control influences dependent on traflic conditions ahead each including an unmagnetized mass of iron.

8. Car-carried apparatus for train control systems comprising, a train control device of the stick type, means for deenergizing said device if two successivecontrol influences arereceived in less than a predetermined interval of time and for again energizing said device it only: one controlling influenceis received insaid interval of time.

.9. Gar-carried apparatus for speed-control systems for railways comprising, a brake control device having a stick circuit and a pickup circuit, and-means tor-opening-hoth of said circuits momentarily and then again 7 closing the stick circuit at one point. when two successive control influencesare received in less than a predetermined time and'for momentarily closing both of said circuits and'then maintaining the stick circuit closed at said point when only one control influence is received in said interval of time.

10. In a train control system, the combination of car-carried apparatus including a cyclic device, and means for restricting the movement of the train it two successive control influences are received during the time necessary to complete the cycle of said device and for removing previous restrictions if only one control influence is received during the time of such cycle; and trackway means comprising pairs of influence transmitting devices of which one device of each pair-is permanently active and the other is active or inactive dependent on traflic conditions ahead, whereby a pair of active elements is adapted to restrict the movement of the train and a single active element of a pair may remove such restriction.

11. An automatic train control system comprising, pairs of influence communicating trackway devices located in the same path along the trackway of which one device of each pair is always active and the other device is active at times only and is controlled in accordance with traffic conditions ahead, and car-carried apparatus which if actuated restricts the movement of the train and which is actuated if a control point is passed at which both devices of the pair are active and which is restored to normal it the train passes a control point at which only one device is active.

12. In a train control system, the combination of car-carried means comprising, a cyclic device adapted to be initiated by a control influence transmitted from the trackway which will restrict the movement of the train it a secand control influence is received from the trackway before its cycle of operation has been completed, and which will remove such restriction if said cyclic device is again initiated but no second influence is received during the second cycle of operation; and trackway means comprising pairs of influence transmitting devices of which one trackwa-y device of each pair is permanently active and, the other is controlled in f accordance with traflic conditions ahead,' whereby if atrain ptL$SBS2MPfilTvOZE tr'ackway devices ctr-which both devices are active the movement of thetrain isrestricted .13.? In an automatic train control system,

the combination of car-carried apparatus comprising, 1 a .rotatahle,device,- means for restricting the movement of the trainiftwo successive "control. influences are received from, the. trackway byua suitable influence receiving device {on thetrain during a, predeterm ned; deg-react rotationof said' devlce and, for removing such restriction in" the movement of the train it only one control influence is received during a similar degree of rotation; and trackway means compris- 1ng pairs of influence transmitting devices for transmitting control influences magnetically through an intervening air-gap of which one device of each pair is permanently active and the other device is controlled in accordance with traflic conditions ahead, whereby it a train passes a pair of trackway devices of which both devices are active the movement of the train is restricted and if it thereafter passes a pairv of trackway devices of which the permanently active device only is active the restriction in the movement of the train is removed.

14. Car-carried apparatus for automatic train control systems comprising, a relay adapted to be momentarily deenergized on the passage of the car over a suitable active trackway device which trackway device is adapted to cooperate with suitable influence receiving means on the carconnected. to such relay, a normally energized stick device which if deenergized restricts the movement of the train said device'having'a pick-up circuit and a stick circuit, a normally inactive rotatable device having a contact associated therewith which is normally closed and which is open during a predetermined degree of rotation of said device which rotatable device is started from rest if said relay is momentarily deenergized and which contact is contained in the pick up circuit of said stick device, and make-before-break contact associated with said relay having its normally closed front contact in said stick circuit and having its back contact in said pick-up circuit, whereby the reception of a single control influence picks up said stick device if it is deenergized and the reception of two control influences during less than a predetermined degree of rotation of said rotatable device causesdeenergization of said stick device.

15. An automatic train control system comprising, an influence receiving element consisting of a magnetic core having a normally energized primary and a secondary coil thereon, a normally energized relay connected in a stick circuit in series With said secondary coil, a normally energized electro-responsive device which if deenergized restrictsthe movement of the train, a rotatable device, means for deenergizing said electro-responsive device if two control influences are received during less than a predetermined degree of rotation of said rotatable device and for restoring said electro-responsive device to normal if only one control influence-'is'received during such degree of rotation, and trackway means comprising pairs of successively located unmagnetized magnetic bodies for transmitting such control influences by inducing potentials in said secondary coil one magnetic body of each pair being provided with a Winding closed in a deenergized circuit under clear trafiic conditions ahead so as to render such body incapable of inducing a Voltage in said secondary coil as a result of the magneto-motive-force lnduced by said primary coil, whereby said electro-responsive device is deenergized when the car passes by a pair of active trackway devices signature.

lVINTHROP K. HOWE.