US1601426A - Train control - Google Patents

Description

I S p 8 1926.

' C s. BUSHNELL TRAIN CONTROL Filed March 25 5 MP in u 3 o w. 9. 8 0b Q vw m 5 F s. 3 H J a w a a 3 w '8 m* x 3 3 m v m E 3 Wm lumm m. w v m: mm l ax s m 2 Q mm wm om S 3 mm m2 m3! mm L. 5 5 mm 8 m N F V n u A u T M 8 m5 m T. w

B N mm NS a: mm mS I?atented Sept. 28, 1926.

UNITED STATES PATENT OFFICE.

CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAIL- VIAY SIGNAL COMPANY, OF GATES, NEW YORK, A CORPORATION OF NEW YORK.

TRAIN CONTROL.

Application filed March 25, 1922. Serial No. 546,711.

This invention relates to train control sys tems, and particularly to parts and circuits for governing apparatus of the cyclic type.

In train control systems of the cyclic type,

that is, systems in which a certain cycle 0t permissive speed is enforced in certain parts of each block when the nextblock in advance is occupied or is in danger due to some other hazard, it is desirable to initiate apparatus for causing the permissive speed and to provide other devices to restore or reset said apparatus atvarious points in the block as soon as the traffic conditions in the next block change. This is desirable because a train running in a clear block should have its speed limited as soon as traflic conditions in. the next block in advance change due to causes, such as, a broken rail, an open switch, the entrance of a train from a siding, and the like; and further because trains running under the control of a permissive speed deviceshould be relieved of such control, and allowed to accelerate as soon as the danger conditions clear up, that is, an intermediate release is desirable. Influences for causing such control are preferably transmitted from one device along the trackway to another on the vehicle through an intervening air gap, rather than by physical contact between such devices. Inductive devices which are constructed on the side of safety are preferably employed for communicating such influences.

lVith such and other requisites in mind, the principal objects and purposes of the present invention are to provide devices working on the correct principle, namely, devices which work on the side of safety, that is, so that a failure, such as a break in a circuit, will have the same effect as a danger influence to limit the speed of the vehicle, and will also cause a failure to reset the device, and to construct such devices with the least number of parts.

More specifically, the objects and purposes are to provide influence transmitting devices which will start to impose a restriction on the speed of the train, and give a warning at any one of a plurality of points in a block when a dangerous condition arises, and which is adapted to reset or remove the imposed restriction at any one of the same points in the block when thedanger traflic conditions clear up; and further to transmit such influences through an intervening airgap inductively by inert track devices (dcvices which do not require any energy when either in their influence transmittingor dormant condition), and suitable cooperating devices carried by the vehicle.

Other objects and advantages of the present'invention will appear as the description progresses.

In describing the invention in detail. reference will be made to the accompanying drawing, in which H Fig. 1 illustrates trackway apparatus of one form of train control system embodying the present invention superimposed upon a typical form of block signal system; and

F ig. 2 is a diagrammatic and perspective view of a car-carried apparatus embodying the present invention, which has been shown in a manner to make it easy to understand the invention. rather than to Show the construction preferably employed in practice.

Traclawag structurc.1n the embodiment of the invention illustrated, the transmission of the desired control influences is produced by track elementswhich are governed in accordance with traflic conditions. Various arrangements of trackway circuits suitable for this purpose may be employed, and it should he understood that the arrangement shown in Fig. 1 is only a typical illustration. Referring to Fig. 1, the track rails 1 of the railroad track are divided into blocks by insulated joints 2, one 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 bat tery 3 and a track relay 4:, the same as in ordinary block signal systems. My invention may be used with or without the usual fixed signals, dependent upon the type of train. control apparatus; and I have illustrated such fixed signals S conventionally, without attempting to illustrate their wel known control circuits and devices.

A plurality of track elements T are employed in each block, which may be controlled by traffic conditions in advance or may be in their active condition permanently on account of a'permanent hazard in advance of such block. These track elements T of my invention, in general, comprise a magnetic yoke or core and an associated coil,

yoke. These track elements T are intendedto transmit control influences or impulses to a passing tram at a plurality of control points in each block in accordance with tratfic conditions in the next block in advance;

In. the embodiment of the invention illustrated-in Fi 1, a plurality of equally.

spaced track elements T are employed in a manner so that=the lasttrackelementis a. shortdistance from the exit end of the block, or'th'e point at which the trainis to come to a predetermined minimum speed. Adjacent each i th'ese'track elements is providedarepeater-relay RR for making the track elements active or inactive, de pendent upon whether the repeater relays are energized or deenergized. The repeater relays are normally energized through a front contact 10 of the track relay 1 o f th'e next block in advance. Although the e re peater relays RR- may be connected in or in multiple, they have been shown connected in series for convenience. This cir- Quit may be traced as tollows:-Beginningthe block, dependent upon the length oi": theparticular block as compared with the distance required for the cyclic device, which is to cooperate therewith, to pertorn-i its function, the remaining elements being equally spaced at fixed intervals, the distance between these elements being dependent upon the car apparatus which isto cooperate therewith.

Oar apparatuc.Tl1e several devices 01" the car apparatus illustrated in Fig. 2 will first be separately described, afterwhich their operation in the particular system in which they are used will 'be described. The car element L comprises a U-shaped-core. 12 terminating in pole pieces. 13.. On one: of the legs is provided aprinr. y coil 1?, the other leg being provided with a secondary. coil S. The car element L isp'referab'lv mounted on the truck eta railway vehicle. in a manner to protect it from iars andvi bration and flOillSllOW and ice in any suitable'inanner. The carelenient is'preterably solocatedlthat its'pole piecesl'S pass adia cent the pole piecesootfthe tract: elements 1, the vehicle'inoves along the trackway. A; control" relay CR" and auxiliary an;

A are employed,which-are constructed so that their moving parts are well balanced to prevent a false actuation thereof, due to jars and vibration caused by the moving vehicle. Although these relays have been shown as being the same, the illustration is merely conventional and in practice the control relay CR will be responsive to a much smaller current and operates smaller contacts than does the auxiliary relay A.

A cam starting magnet CS for setting the cyclic system into operation is employed. This cam starting magnet compriseswindings 1 1 and 15 supported on a Ueshaped yoke 16. Aniarmature 1'7 normally held away from the yoke 16 by a spring-18B connectedto thecollar 19 byxa bifurcated lug 20. hen the cam starting/magnet CS isenergized; the cyclic SYStBHLlS held 'in its normal andineitlect-ive position, whereasit this cam startin magnet CSis-deenergized; i118 cyclic system will be actuated-ate provice a continuing decreasing permissive speed Tl'ie'speedcontrol devicesot the car-carried apparatusillustrated may take any one of the various fo ms usually employed.

For convenience the specific type of cyclic control system shown by the patentlto Simmen, 1,150,309, granted Aug.- 17, 1915 has been illustrated.

The speed control devices include a centrit'ugal device driven by beveled gearsflll and 21 from the wheels'oit avehicle. This centrifugal device has been-illustrated in conventional manner. and comprises vertical shaft 22 supportedin a bearing; 28; the shaft is connected tothe'beveled gear 21 and has pinned thereto a cross bar 2 3 connected to a slidab-lecollar 24 by two pairs of links 25; Each pair ot'links is pivot-ally connectecL t" a centritagalweight- The slidable collar is biased away from the cross bar 23 by a springQ'Z. It will be noted that the collar-Qlwillbe movedto various positions on the shaft 22, due to the centrifugal force of the weights 26 acting against the spring-27 as the shaft 22 is-ro tated. I

At the end of'th e shaft 22 isprovided a beveled gear 2,9 continuously in-uiesh with the gear 30 which is pinned to ashaft 31, having its one end'supported'in a bearing 32. The other endot theshatt'ill. is-rotat ably supported in the collar19." Near the collar 19 the sha'ttfill is provided with worm 32, which is arranged to 'operatively engage the worm wheel 33' when the cam starting magnet CS is deenergizedi This worm wheel rigidly connected" to a shaft supported" by bearings- {not shown), and; is provi led", with projecting lucgfio. Adjacent tli shaft is provided a nanny sta es; The;coilspriiig.f37 on the shaft has ltSG de""fi te l l 'g' 0110p posite sides of the stop 36, which ends, project above the stop 36 a distance to pass on opposite sides of the lug 35, whereby the worm wheel 33 is biased into its normal position as illustrated.

On the shaft 3 1 is keyed a reset contactor X. This reset contactor comprises a disc 38 of insulating material provided with contacts 40, 41, 42, 43,4 1, 15, 50, 51, 52, 53 and 54. spaced and located in a manner as will appear when the operation of the apparatus is described. Adjacent the reset contactor X is provided an insulating block 55, to which are fastened brushes or contact fingers 56, 57, 58 and 59 adapted to be connected by the contacts on the insulating disc 38. On the periphery of the insulatingdisc 38 is secured a cam 60 in any suitable manner. This cam 60 is adapted to connect the spring contact 61 with the contact 62 when the reset contactor X is rotated substantially one-half revolution in either direction.

To the insulating disc 38 is bolted a cam 63. The slidable collar 24 of the speed responsive device is provided with a groove in which is contained the bifurcated end of an angle lever 64, which is pivotally supported on the pin 65. The other end of the angle lever is bifurcated and connected to a floating lever 66 by a pin 67. The other end of the floating lever 66 is provided with a bifurcation in which is pivotally supported a roller 68. At an intermediate point on the floating lever is pivotally fastened a link 69, which has its opposite end connected to an arm 70 of a sector 71 by a pin 72. This sector 71 is biased by a spring 7 3 in a direction to urge the roller 68 against the cam 63.

The working face of the sector 71 comprises concentric surfaces 74, 7 5 and 76, the pur poses of which will be pointed out hereinafter.

Against the working surfaces of the sector 71 is biased a roller 77 pivotally secured to the contact finger 78 in any suitable manner. Under normal conditions, that is, when the roller 77 is in contact with the surface 7 1, the contact finger 78 will be forced against the contact finger 79, which in turn will be biased against the contact finger 80.

In order to advise the engineer when the railwayvehicle has almost reached the permissive speed, a warning signal W has been provided. This warning signal comprises a whistle 81 adapted to be controlled by an electro-pneumatic valve 82, which will connect the whistle with a supply of pressure fluid through the pipe 83 when the electropneumatic valve 82 is deenergized.

Another warning signal has been provided which comprises a bell 84. connected in series with a green lamp G through a battery 85 in a circuit which may be traced as follows :Starting from the battery 85, wire 86,

bell 8 1, wire 87, lamp Gr, wire 88, back to the battery 85. A normally open switch comprising the stationary contact 89 and the movable contact 90 is positioned adjacent the collar 19, so that when the collar is in its lower position the contacts 89 and 90 will be closed, thus completing a circuit for shunting the lamp, thereby connecting the bell 84 directly across the battery 85, which will allow sufficient current to flow through the bell 84 to cause it to sound. This circuit may be traced as follows :Beginning at the battery 85, wire 86, bell 84, wires 87 and 91, contacts 90 and 89, wires 92 and 88, back to the battery 85.

Means have been provided for applying the brakes as illustrated by the brake applying device K which has been shown conventionally as an electro-pneumatic valve. This brake applying device K embraces provision for limiting the amount of reduction of brake pipe pressure when an automatic brake application is made, and prevents the engineer from recharging the brake pipe to prevent such a brake application taking effeet, all in conformity with well recognized air brake practice. This brake applying device K when deenergized will apply the brakes of the vehicle, and when energized may automatically release the brakes or permit the brakes to be released by the engineer manually. A reset switch for resetting the brake applying device under certain conditions has been illustrated in a simplified and conventional manner by a push button 93.

Opemtd0n.1n the trackwa-y system illustrated in Fig. 1, the track elements T in the rear of an unoccupied block are in their clear trafiic condition, because their coils 7 are in a closed circuit of low resistance. The track elements T in the rear of an occupied block are open circuited, and are therefore in their effective or influence transmitting condition. This is due .to the fact that the circuit for energizing the repeater relays RR has been opened at the front contact 10 of the track relay in the block in advance. In an occupied block, the track elements T may be in their open or closed circuit condition, dependent upon whether or not the block in advance is occupied, or danger exists due to some other cause.

Vith the car-carried apparatus in its nor mal condition, that is, with the vehicle moving in a block when the next block in ad vance is clear, the primary or exciting coil P of the car element L, which is connected in series with the brake applying device K, is included in a circuit which may be traced as follows :-Beginning at the terminal B of a battery, wire 121, reset switch 93, wire 94, contact fingers 79 and 7 8, wire 94, brake applying device K, wire 95, primary coil P, wire 96, back to the common return wire C. lVith this latter circuitenergized, the primary coil P produces a magneto-motivefo*ce in the car element'L tending to send flux through the secondary coil S on the other leg of the car element. This-magnetomotive-force will, however,only produce a very small amount of flux in the secondary coil Son account 'of the large reluctance due to the-air gap between the pole pieces 13.

The control relay GR is normally energized through a stick circuit, which may be traced as follows :Beginning at the terminal B of a-battery, wire 97, front contact 98 of the control relay CR, wires 99 and 100, winding of the control'relay CR, wire 101, secondary coil S, wire 102, back to the common return wire C.

lVith the control relay GR in its energized condition, theauxiliary relay A will be encrgized through a stick circuit, which maybe traced asfollows :Beginning. at the-terminal B of a battery, wire 103, front contact t'ofcc-ntrol relay CR, wi es 105 and 10-6, front cont-act'10i of the auxiliary relay A, wires 108-and 109, winding of the auxiliary relay, wire 110, back to the common return wire-C.

lVith the auxiliary relay-A in its energized condition, an energizing circuit for the cam starting magnet CS may be traced as fol lows :Begininng at the terminalof a battery B, wire 11', frontcontact 112 of the auxiliary. relay A, wire 113, windings 1% and 15of the camstarting magnet CS, wire 11&, to the common return wire-C.

Assuming now that the railway vehicle is movingalOng the track in its normal conditionas illustrated in.Fig. 2, with the worm 32" disengaged from the worm wheel 33, acertain maximum .pern'iis sivespeed will. be allowed. If the engineer increases the speed of the train, the slid-able collar 21 will be moved up onthe shaft 22 by the action of the centrifugal weights .26. This willcause the angle lever 6% to be tilted in a direction to tension the link 69, thereby eventually causing thesector 71 to turn a sufficient distance to allow the roller 77 to fall upon the surface 75.

As the roller 77 rides off of the surface 74 on tothe surface 75, the contact fingers 78 and 79 are both moved toward'the left to breakthe contact between the spring fingers 79 and 80. This will cause the warn ing signal 1V to be sounded, thereby informing the engineer that the permissive speed has been reached. If new the engineerstill further increases the speed of thevehicle, the roller 7'? will ride from the surface onto the surface 76. This will cause the spring finger78 to move from the. spring finger 7 9, thereby interruptingjthe circuit'through the brake applying device K, and applying the brakes inamanner as heretofore described.

Assume now thata railway vehicle with its train control apparatus in its normal condition, and traveling atta speed below' the maximum permissive speed, is entering a caution block. As the car element L passes over the first of the series of track elements T, these track elements being in their open circuit or danger condition because the block in advance is occupied, causes a momentary increase of flux through the car element L, which will decrease to its normal value when the carelement L recedes from the track element T. This sudden increase and decrease of flux through the car element L in dnces a voltage in the secondary coil S simi lar to that of'a single cycle of alternating current, the secondary coil S being wound and connected so that the first wave of uni.- cyclic'E. M. F. will oppose the volta e of the battery in the secondary circuit. This opposing E. M. F. will decrease the current nori ally flowing in the'control relay CR to a value to drop its armature, thereby interrupting its stick circuit and permanently deenergizing the control relay until it is re set by some other means.

ihe dcenergization. of the control relay CR- deenergizes the auxiliary relay Aby the interruption of the stick circuit of the auxiliary relay atthe front contactl the control relay CE. The dropping of the auxiliary relay A de'energizes the cam start ing magnet US by interrupting its ci .it at the front contact 112 of the auxiliar 3 lay. The deenergization of the camstarting magnet CS causes the spring 18 to press the worm against the worm gear 33, thus causing the worm gear 33, reset con actor X, and cam 63 to be rotated in acco lance with the movement of the train ale Y track. The deenergization of the cam is ing magnet CS also causes the collar to move the spring contact against the stationary contact 89, thereby shin the green lamp G and sounding the bell to apprize the engineer that the yclic system is in operation.

After the reset contactor X has moved a short distance in the clockwise direction, it causes the contact 50 tobridge the brushes 56 and 57, thereby completing a pick-up circuit for the control relay CR, which may be traced as follows :Beginning at the battery B, wire 115, contact brush 5?, contact strip 50, contact brush 56, wires 116, 11'? and 100, winding of the control relay (5R, wire 101, secondary coil S, wire 102, to the common return wire C. This causes the control relay CR to pick-up, thereby closing its front contact 98 and completing its pick-up circuit heretofore traced.

As the train advances in the bloc-l between the first and secondftrack elements T, the reset cont-actor X is turned to some point so'that'the contact brushes 56 and 5'? will be in" contact with the insulating, disc between the contacts- 50' and 1,, thus setting up acertain permissive spec dependent upv D J Li on the condition of the cam 63, this cam 63 being shaped so that it gradually decreasing permissive speed is imposed upon the em gineer which may conforinto any particular speed distance curve, for instance, it may I conform to the speed distance braking curve of the particular vehicle under a service brake application. If the engineer exceeds this permissive speed, the whistle 81 will be sounded, and the brake applying device is: will be actuated in substantially the same manner as heretofore described.

Assume now that the second track element T of the series of elements in .the particular block in question is passed over. As the vehicle passes by this second track element T, the control relay CR will again be me mentarily deenergized, thereby breaking its stick circuit in substantially the same man ner heretofore.

Assume now that the train is proceeding between the second and third track element,

the cam 63 being gradually rotated, thus enforcing a gradually decreasing permissive speed. As the contact disc reaches a position so that the contact strip 51 bridges the contact brushes 58 and 59, nothing particularly will result, because the circuit completed by these contact brushes is open at the front contact 10-1 of the control relay CR.

Assume now that the vehicle proceeds in the block until the contact brushes 56 and 57 are bridged by the contact strip 52. This will cause the control relay CR to be picked up, thereby completing its stick circuit through its front contact 98 in substantially the same manner as heretofore described.

Assume now that the. train is proceeding between the second and third track element T of the series of elements in the block,aud that trahic conditions inthe block in advance clear up. As the third track element of the series of elements is now passed over, it being in its closed circuit or clear trafiic condition, because the track relay 4 of the block in' advance and likewise the repeater relays are energized, no appreciable voltage will be generated in the secondary coil S of the car element. This is accounted for by the fact that a slight change of flux through the track element T causes a large current to flow in the windingv 7 connected in a circuit of low resistance. This current by welhknown principles of alternating current flows in a direction to oppose the :lux which produces it. Consequently, only a very small amount of flux will traverse the track element T, and likewise only a small change of flux will take place in the car element L, thus inducing only a very nnall voltage. This small voltage induced in the circuit, including thecontrolrrlay CE, is insuflicient to cause the control relay to drop.

Assume now that the train continues to travel between the third and fourth track element of the series illustrated, thereby continuing a gradually decreasing permissive speed to a point where the contact strip 53 bridges the contact brushes 58 and 59. This completes a pick-up circuit for the auxiliary relay A, which may be traced as follows Starting from the terminal B of a battery, wire 103, front contact 104 of the control relayCR, wires 105 and 118, contact brush 58, contact strip 53, contact brush 59, wires 119 and 109, winding of the auxiliary relay A, wire 110, to the common return wire C. The energization of this pick-up circuit causes the auxiliary relay A to be permanent- 1y energized through its stick circuit heretofore traced, and further closes the energizing circuit of the cam starting magnet CS, thereby raising the worm 32 away from the worm gear 33, thus allowing the spring 37 to return the worm gear 33, the reset contactor X, and the cam 63 to their original and normal position.

The energization of the cam starting magnet CS allows the spring contact 90 to leave the contact 89, thereby illuminating the green lampG, and decreasing the current through the bell 84: to an extent to silence the same.

The sequence of operation in passing over succeeding track elements when all these track elements are in their danger or open circuit condition at the time they are passed over is repeated until the last track element of th-e'series is passed, thereby gradually reducing the permissive speed to a certain low maximum value, for instance, such as fifteen miles per hour. If the vehicle continues to move along at this low permissive speed until the worm gear 33 has turned through an arc of substantially 180 degrees, the worm gear 33 will be stopped. on account of'the mutilated portion 120 which does not allow the worm to further rotate the worm gear on account of the absence of teeth at the mutilated vpart. lVith the worm gear in this position, the cam 60 will be in a position to hold the springcontact 61 against the stationary contact 62. lVith these contacts in thisposition, the engineer, being fully aware of the trafl ic conditions, may now remove the restrictions imposed by thetrain control apparatus by pushing reset switclr93, thereby closing a releasing circuit which may be ,traced as follows Beginnin at the terminal B of a battery, wire 121, reset sw ,eh 93, wire 122, contacts 61 and 62, wires 1 3, 117 and 100, windingof the control relav CR, wire 101, secondary coil S, wire 102, thus picking up the control relay CR-- The energization of the control relay will cause the auxiliary relay A to be energizedthrough a circuit which may be traced as follows :-Beginning at the terminal B or abattery, wire 103, front contact 10-1 of the control relay CR, wires 105 and 11S, contact brush 58, contact strip 45, contact-brush 59,

wires 119 and 1G9, winding ofthe auxiliary relay A wire 110, to the common return wire C. The energizaation of the auxiliary relay A will energize the cam starting mag net CS, which will allow the cyclic system to return to its original position by the aid of the spring 37. p

In order that the present invention may be applied to enforce safe limiting speeds at points ina block where permanent hazards exists, suchas, dangerous curves, approaches to sudden down grade, bridges, yard limits, etc, some of the trackelements may be permanently put in their danger or influence emitting condition. This may be done by ving their coils 7 open circuit-ed, or by omitting thenr altogether. For instance, suppose that passingtrains should not be permitted to enter a certain block at more than, say 1-0 miles per hour, under any con dition, and assume that-such a speed limit will be enforced by the particular car apparatus used when two danger track elements have been passed over. To enforce sucha speed limit for all trains of a class, regardless of whether or not the next block in ad vanee is occupied, the last two elements of the block in the rear should be permanently in their influence transmitting condition. Vi it-h an arrangement of this kind, the second last track element of the block in question would start the cam under clear trafiic conditions, thus bringing the speed down to the desired amount after which an automatic release would take place in a manner as already explained. If, however, theblock in advance were occupied, the cam would be initiated at the first element ofthe series of track elements employed and enforce permissive speed limits in the usual way. If a higher permissive speed than 40 miles per hour, as just explained, is'desired on account of some pcrmanenthazard at the entrance to a block, only the last track elementof the block in the rear is constructed to be permanently active, and in this event the canals initiated by the deenergization of the relays CR and A when passing by the lasttrack element. The control relay GR is again picked up when contact fingers 56-and 57 are bridged by contact 50,- and the auxiliary relay A, and in turn the camstarting magnet CS, are energized when the contact fingers 5S and 59 are bridged bythe'contact 51, so that the restriction is removed upon en tering the following block, assuming this following block to be clear. If, however, this following block is a caution block and the first track element in this block is spaced the same distance from the last element of the preceding block asjthat of the spacing between successive elements in the same block, a further restrictionin the spe'edre sults as more clearly brought out in the operation of the system. On the other hand, if the first track element in this following block is located so far in advance of the last ele ment of the block in question that the contact 51 bridges spring fingers 58 and 59, the cam will again be reset, as already explained, but will again be initiated when the first track element of the following block is reached. 7

l t should be noted that contacts 4-0 and l1, similarly to the contacts 50 and 5%, have been provided on the opposite side of the insulating disc 38. These contacts are provided so that if the vehicle is changed end for end in those types of systems where a car element is provided on each side of the vehicle, the proper circuits are closed in propersequence when the locomotive is traveling tender ahead. i

It should be understood that any number of track elements maybe employed in a se ries in each block, since all that'is required is that they be of a proper number and properly spaced to correspond to the spacing of the contact strips on the reset contactor X. For instance, the track elements are so spaced that the second element is passed over after contact 50 has bridged the contact fingers 56 and 57 but before contact 51 bridges contact fingers 58 and 59. It is, however, desirable to space the track elements of a series equally, and start such series'at a point in the block so that the cam will enforce the low limiting speed heretofore mentioned before the train reaches the end of the block. Although the cam 63 has been illustrated as being circular and eccentrically mounted, this cam is preferably shaped to enforce a predetermined brake application curve at each point during its movement, that is, to enforce a predeterm ned speed such that if the train exceeds it, the brakes will be applied-in time to stop the train before it reaches the end of the block.

In the embodiment of the invention illustrated, the simplest form of cyclic permissive speed enforcing apparatus has been illustrated. This has been done to make it easy to understand the invention as applied to a cyclic tvpe of train control system generally It should, however, be understood that a plurality of cams may be used, of which a particular one is selected for a particular'block instead of using the single cam illustratedfor all blocks, suitable selecting means being employed'for this purpose; or any other means may be used'to modify the effect of a given camby employing variable lever arms, changeable gear ratio apparatus and various other devices used for varying thepermissive speed enforced by a cam, depende'nt'upon the character of the particular block in which the device is used at the time.

One of the characteristic features of this invention, which will be readily understood in view of the foregoing description, is that the brake control apparatus on a train will be set into operation at an intermediate point in any block, in the event that, after said train entered that block, danger conditions are created in the block next in advance, due to a train backing into that block, the breaking of a rail, the opening of a switch, or the like. Upon such change from safe to clangerous trafiic conditions in the block next in advance, the relays RR are deenergized, opening the circuit to the coil 7 of each of track elements T of the block next in the rear, so that the brake control apparatus on a following car is automatically set into operation irrespective of the signal indication at the time said train entered the block, the instant it asses the next track element. In other words, the system of this invention provides not only intermediate release or restoration, but also intermediate initiation or: operation, of the train control equipment of a train in a block.

If, while a. train is moving at an intermediate point in a block, this block changes from a clear to a caution block, possibly because another'train has backed from a sec ond block in advance into the block in advance, the car-carried cam mechanism is initiated at the next track element which may be the second or third, or. even the lastelement in the block, and under this condition the train is restricted in the usual way providing the train which backed up did not back up far enough to leave the second block entirely, that is, both the track elements in the block in question and the track elements in the first block in advance thereof are active. This will cause the permissive speed to be gradually restricted; proceeding, of course, on the assumption that the last element in one block and the first element of the next block in advance are spaced the same distance as are the successive elements within such blocks. so that, the last element of one block and the first three elements of the next block in advance form a series the same as the four elements of a block. In the case just mentioned the train in question would undoubtedly be restricted to its minimum speed before it would reach the other train, thus affording full protection. If, however, the tra n which backed up would have backed upso far as to entirely leave the second block in' advance before the train in question is restricted to its minimum speed, that is passed over four active track elements in the particular embodiment illustrated, the train in question would be released and a collision at low speed might occur. These last mentioned circumstances are, however, not very aptto happen under actual working conditions, bearing in mind that wayside block signalling on double track railroads do not provide for such train movements and such movements are ordinarily not permitted or contemplated.

Another characteristic feature of the invention is that, after a train has traveled completely through a caution block, without reoperation. The significance of this will be appreciated when it is observed that the track elements in a block occupied by a train may be either in the clear or stopping condition depending 'upon whether or not the block next in advance is unoccupied or occupied. Consequently, a train entering an occupied block may encounter track elements either in the clear or stopping condition, and it will be evident that, from the standpoint of safety, the train coming into such occupied block should not be able to receive an automatic restoration by the influence of such track elements, inasmuch as said restoration is not proper in view of the train immediately ahead, but may occur in the event that the. block next ahead is not occupied. It will be noted that the manual restoration is possible only after the cam has traveled to its minimumspeed positionfassuring that the train has reduced speed before such manual reset is possible. Thus, the manual resetting device may be in the locomotive cab, directly accessible to the engineer, since it is effective only in case the speed has been reduced to a safe minimum. However, in order to assure that the engineer will have to manipulate this resetting device each time, and can not fasten it down, the arrangements shown and hereinbefore described are provided such that operation of the resetting device results in a brake application. In this connection. it will. be observed that the brake controlling; device K may be constructed to have a brief inherent time interval or delay in its operation, so that, while the engineer can not permanently fasten the resetting device in its 'operated position, he is able. to manipulate it without producing an actual brake application.

l Vhile it is contemplated that the system of speed control embodying; this invention will preferably be employed in connection with the usual trackway fixed signals, signaling devices are provided as hereinbefore explained, to inform the engineer when he enters a caution block, and also to advise him when his speed has approached the critical limiting speed. The signaling devices, comprising lamp G'and bell 8 in conjunction 'withthe trackway signals enable the engiiSfril'l' its: active condition at the time.

3. In a train control system-comprising a lneer to determine Whether or notian initiation: of the speed control apparatus takes place in the regular way near the entrance to a block, or'occurs at an intermediate point in the block on account of a change in tra'liic conditions in the neat'block inadvance from clear to danger.

In order to disclose the nature of the invention, one specificembodiment thereof has been shown and-described; but it will be1ob vious that many modifications and adaptations of this specific structure may be employed in practice without departing, from the underlying principles and mode of op 'eration of the invention. For example, while influence communicating means operating inductively have been-shown, and one specific typeoi a brake control apparatus, dependent upon failure of the :vehicle to conform witlna prescribedvariable speed limit, otherspecific means of asimilar character,:t'or the-same purpose maybe used; and'l desire to have it understoodthat the particular parts and circuits shown and described are susceptible: of modification, adaptation, oruaddition, depending upon the nature and extent of the train regulation desired, aswellvas' thewparticular character 01" means to be employed, and that the invention is not intended to bein any way limited by 'the specific disclosure herein made.

What I claim is 1. In a train control system For railways divided into blocks comprising a cyclic device which will enforce a: gradually decreasing permissive speed depending on the position of the train in the block when initiated, means wholly on the vehicle for automatical- 1y restoring said device when the train has traveled a predetermined distance. after said device has been initiated, and meanslocated at a plurality of pointsalong the track for at times initiating; said device and at other tims preventing said vehicle carried restoring means from automatically restoring said device.

2. In a train control system comprising a permissive speed device adapted to enforce i a restricted speed When initiated by its passage over-an active trackWa-y device, a plurality of trackway devices spaced predetermined distances apart alongr the-'trackway each adapted to be in an active or inactive condition, and means Wholly on the train and associated With said permissive speed device for restoring said device only after the train has traveled said predetermined distance after said device has been initiated and upon its passage by. a trackway device which is in its inactive condition at the time 'but which is incapable of restoring said device it said last mentioned traekivay device permissive speed device on the vehicle which if initiated will conditionally restore itseit after yarious predetermined distances of travel, and an-apparatus partly on the vehicle and partly at points along; the track for initiating said. device, allowing said. device to restoreit-self ormaintaining said. device inv operation when;passing such point dependent-npon tralfic conditions in advance.

in a train controlsystem of the cyclic typecomprising a permissive .speed device adapted to be initiated ctor entorcing restricted speeds automatic means for restorinemsaid device when danger conditions. in advance clear up, and manual means for restoringsai (1- device only operative when the speed has been i'QStTlCtGd-"t/OEZL predetermined extent.

. In an automatic train control system, the combinationlot signaling means; for indicating clear and caution, respectively, inifluencegreceiving means on the vehicleator cnanging'. the indication of said signaling means from its normal clear indicating to itseaution indicatingcondition, and other car-carried vmeans for ,ehangingthe indication from caution to' clear after a predetermined distance of: travel ,ot the vehicle un less an intervening control influence has been received.

(3. An automatic train control system comprising' a cyclic signaling-means iornindicating' l-favorable and unfavorable tratlic conditions-means to receive control influences' rfrom the trackwav for initiating said cyclic device and indicating; unfavorable in stead oi favorable trafiic conditions, [and means, governedibysaid cycliejdeyice for restoringitto itsnormal favorable trafiic con- ClltlODS: after. a predetermined distance of travel of the vehicle effective if nointerven one part ct block, means for picking up the other of said relays when a car occupies another-part oi the block provided the first mentioned relay is energized at the time.

and an electro-responsive device operated ointly by said relays.

j 8. Car-carried apparatus for automatic train control systems comprising, a plurality of devices of the stick type, means for picking up one of saidstick devices at one part of a block; means. for picking up the other of said stick devices providing the first device is in its pick-up position when the train passes anotherpointinthe block, and

'meansgoverned by said two devices.

39. A train control systemmmnprising, a cyclic device, car-carr1ed;means for restrictfing; the speed. of the vehicle in accordance with? the distance -'travel ed aften said device has been initiated, means carried Wholly on the vehicle for restoring said speed restricting means operative when an intermediate speed limit is being enforced, and traclrway devices located at a plurality of points along the track adapted to initiate said apparatus under danger tratlic conditions it said device has not already been initiated, prevent it from being restored under dangerous traflic conditions ahead, and allowing it to be restored under clear tratiic conditions ahead.

10. In a train control system of the cyclic type comprising a permissive speed device, traflic controlled means for initiating said device, automatic means for resetting said device to its initial position, and means operable manually. only and effective only after the speed of the train has been restricted to a certain minimum for resetting said device.

11. An automatic train control system comprising, a stick relay having a pick-up and a stick circuit, a second relay having a pick-up circuit including a front contact of said first-mentioned relay and having a sticlr circuit, means for closing the first-mentioned pick-up circuit after a predetermined distance or movement of the vehicle from a predetermined point along the trackway, means for closing the pick-up circuit of the second relay providing the first relay is al.- ready picked up after a further distance of movement of the vehicle along the trackway, and train control means governed by said second mentioned relay.

12. In a train control system, car-carried apparatus comprising a cam adapted to be driven from the wheels of a vehicle, means for disengaging the driving connection for said cam, a visual signal and an audible sig nal connected in series, and means for shunt- -1ng said visual signal when said cam is in driving relation with said wheels.

13. Car-carried apparatus for automatic train control systems comprising, a cyclic device adapted to be initiated by trackway devices, and means for automatically restoring said device if less than a predetermined number of influences are received from suitable trackway devices in a predetermined distance of travel.

14:. In an automatic train control system, the combination of a cyclic device normally held in a maximum permissive speed condition which if initiated gradually assumes more restrictive speed conditions, means partly on the vehicleand partly along the track for initiating said cyclic device, and means for restoring said device or continuing it in operation to further restrict the speed of the vehicle at any one of a plurality of points in its travel from its maximum to its minimum permissive speed condition, including spaced traclrway devices capable of transmitting one kind of control influence only. I

15. In an automatic train control system, the combination of a cyclic device normally held in a maximum permissive speed condition which if initiated gradually assumes more restrictive speed conditions, means partly on the vehicle and partly along the track for initiating said cyclic device, and means for restoring said device or continuing it in operation to further restrict the speed of the vehicle at any one or" a plural ity of points in its travel from its maximum to its minimum permissive speed condition, including spaced trackway devices only capable of transmitting control influences under dangerous traffic conditions ahead 16. An automatic train control system comprising, a permissive speed device normally in its maximum permissive speed condition, means partlyon the vehicle and partly along the trackway for initiating said device to set up gradually decreasing permissive speed limits, and means governed by said device for restoring it to its initial condition when reaching a predetermined intermediate speed limit unless a control influence is transmitted from the trackWay to the vehicle during the time said device changes from its maximum to said intermediate speed condition.

17. An automatic train control system comprising, a permissive speed device which sets up a maximum permissive speed when in its normal condition and which if initiated sets up gradually decreasing speed limits in accordance With the movement of the vehicle along the traclrway, automatic means on the vehicle tending to restore said device at intermediate points between the maximum and the minimum permissive speed, and trackway means adapted to initiate said device and prevent it from being automatically restored when danger traflic conditions ahead exist.

18. An automatic train control system comprising, a permissive speed device which sets up a maximum permissive speed when in its normal conditions and which if initiated sets up gradually decreasing speed limits in accordance with the movement of the vehicle along the trackway, means for automatically restoring said device in accordance with traffic conditions ahead, and manually operable means for restoring said device effective only it operated while said permissive speed device is in its minimum permissive speed condition.

19. An automatic train control system comprising, a permissive speed device which sets up a maximum permissive speed when in its normal condition and which if initiated sets up gradually decreasing speed limits in accordance with the movement of the vehicle along the trackway, means wholly on the vehicle for restoring said device, means partly on the vehicle and partly along the trackway for initiating said device and for preventing it from being restored bysaid vehicle carried restoring means in accordance with trafiic conditions ahead. and means for giving" an indication when said device is in its initiated condition and for giving another distinctive indication when it is in its restored condition.

20. An automatic train control system comprising, a permissive speed device on a railway vehicle normally maintained in its maximum speed position and which it initiatednioves to more restrictive speed conditions in accordance with the movement of the vehicle, means governed by said device causing" a primary and a secondary restoring operation, the successive operations of which without an intervening initiating operation Will restore said'devi'c'e to its initial norinal condition, and means'partly on the vehicle and partly along the'trackway for producing initiating operations at a plurality of points in each block under dangerous trafiic conditions ahead, whereby the permissive speed device is initiated to move from its maximum speed position to an intermediate speed position or the permissive speed device is permitted to continue in operation from an intermediate speed position to a lower speed position in response to such an initiating operation. i

21. Means for effecting initiation and restoration respectively of speed control apparatus for auton'iatic train control systems comprising, car-carried means for initiating said speed control apparatus upon the reception of a control infiuenceby suitable infiuence receiving :means transmitted from the trackway near the entrance of .a block,

of the intermittent inductive type in whichv control influences corresponding to danger ous traffic conditions ahead only are transmitted from the trackway to the vehicle, the combination opt car-carried apparatus including a permissive speed device which it initiated by such control influences aplurality of times in succession restricts the speed of the train to a value depending on the number of times it has been initiated, and which device if initiated is automatically restored ii thetrain travelsa predetermined distance without receiving such a control influence, said apparatus efi'ecting an automatic brake application of the actual speed of the train exceeds the permissi ve'speied, and a plurality of spaced trackway devices each transmitting a controlinfiuence to the car-carried apparatus under adverse trafiic conditions ahead when the train 'passessuch device, whereby the train is restricted to its lowest permissive speed value it the train passes the requisite number of active trackway devices and is automatically released after the speed has been :onlyrestricted to an intermediate value it traffic conditions ahead clear up in the meantime. i

i In testimony whereof '1 hereto. affix my signature. r

CHARLES s. BUs uE L.

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