US1730843A - Automatic train-control system - Google Patents

Description

Oct; 8, 1929. c. s. BUSHNELL 1,730,843

AUTOMATIC TRAIN CONTROL SYSTEI Original'Filed May 18, 1921 FIGJ 0 TIME RETARDED T4 BlAszb CLOGK-WISE lNVE TOR fiTORNEY Patented Get. 8, 1929 UNETED STATES PATENT OFFICE CHARLES S, BUSHNELL, OF ROCHE$TER, NEN YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK AUTOMATIC TRAIN-CONTRUL SYSTEM Original application filed May 18, 1921, Serial No. 470,552. Divided and this application file-'1 February 25,

This invention relates to automatic train control systems for railroads, and more particularly to the car equipn'ient of such systems, and is a division. of application No.

$70,592 filed May 18 1921,

' proper performance of the automatic apparatus. he may perhaps be more lax in his observ nce of the usual block signals, since he will feel that the automatic devices will in some way give a special warning or apply the brakes automatically in case of danger. it is considered objectionable, however, to take away the vigilance of the engineer, because modern block signal systems are very r0 fable and cflicient, and engineers as a rule a e highly trained, experienced and careful operators, so that if the engineer becomes negligent in observing the signal indications or in acting upon them, there is sacrificed a large proportion of the safety of train operation at present obtained by the signal systom and the care with which the engineers ordinarily observe and obey the signals. It is evidei that the ultimate safety of the train is more d if the automatic train control system is supplementary to the block signal stem and the vigilance of the engineer, rather than as a substitute therefor; and if the engineer can he encouraged or forced to observe and, act upon the indications of the traclm'ay signals, a serious accident can result only when signal system, the engineer, an d the train control apparatus all fail at the same time.

ll'ii these considerations in mind, one obof the present invention is to provide a cm of automatic train control in which a penalty is auton'iatically enforced if .ieer Fails to observe a caution or stop signal, and fails to take some appropriate action in recognition of such unfavorable "l indication. Iii: the engineer observes "Ication and acts accordingly, the pen not be enforced and the engineer is ouragco to observe and act upon the mdications. According to the-present Serial invention the penalty in question consists in causing an automatic brake application, or in imposing some suitable form of control, which persists until a reset device is manually operated. c This reset device is preferably nrade accessible only from the ground or is arranged in some other way so that it cannot be used without great trouble and annoyance, and. is also protected so that it cannot be maliciously stoned down, or manipulated in such a wav as to avoid the penalty and defeat the purpose of the invention.

This invention is in the nature of an improvement upon the system disclosed and claimed in the application of \V. K. Howe, Ser. No. 427,110, filed July 80, 1925; and the patent to Howe No. 1,551,515dated August 25, 1925.

in the accompanying drawings;

Fig. 1 is a diagrammatic view of one arrangement of tracl zway circuits applicable to the present invention;

Fig. 2 is a diagrammatic view of a car equipment, the parts and circuits being shown more particularly with the object of making the functions and mode of operation easy to understand, th an with the idea of showing the precise construction and arrangement of parts preferably employed in practice; and,

Fig. 3 illustrates a modified wiring arrangement and construction of the car equipment.

Referring to Fig. 1, the track rails 1 of the railroad track are divided by insulated clubs 2 into blocks in the usual way, one block N with the adjacent ends of two other blocks ll and O being shown; The parts and circuits associated with the several blocks are the same, and for convenience these will be given like reference characters with distinctive eX- ponents. Each block is provided with "the well-luiown nominally closed track circuit commonly used in block signal systems, comprising a track battery 3 and a track relay 1-. The usual trackway fined signals S are illustrated conventionally, and since they may take various forms, such as semaphore nals or color light signals, and may be controlled in any of the welhknown ways, no attemnt has been made to illustrate their conclearances will permit. on

trol circuits and devices, it being understood that these signals will give the usual clear, caution, ant. stop indications and will be obeyed in accordance with the rules in force on the particular railroad.

In the particular embodiment oi? the invention illustrated, it is assumed that the transmission or communication of the de sired controlling impulses or inih ences from the trackway to the moving trains for governing the automaticapparatus thereon in accordance with t'ailic conditions, is accomplished inductively, that is, through an intervening air gap. ,v "hile this inductive type of impulse transmitting means may take any one of various well-known terms, there is illustrated an arrangement comprisa track element T.

The track element 'l comprises in genera a U-shaped yoke or core 5 of magnetic material, with coils G thereon. The coils (3 are wound and connected in series in such a way that the electro-motive-tor"es generated in he respective coils by flux passing through the yoke 5 are cumulative or additi. TllQSQ track elements T may be located and con trolled in va 'ious ways, dependent on, on trattic conditions ahead, but in the p imilar arrangement shown in Fig. 2, track element T is located at the entrance to each block, a short distance in the rear of the insulated joints 2, the normal direction of tmtic being from left to right, as indicated by the arrow. The coils 6 of this track element T are connected in series in a normally closed circuit of low resistance, including the front contact of a line relay D. The energizing circuit for the line relay D includes a front contact of the track relay a of the correspoocrn block, and a front Contact of the track relay 1- of the next block in advance. Thus, the coils 6 oi the track element T at the ent 'ance to a given block are in a closed circuit under clear traliic conditions, but are open-circuited under caution or stop conditions, that is, when the corresponding block or the next block in advance is occupied. These trail elements T may be located crosswise of the track between the track rails shown, r lengthwise, between or outside of either track rail, and in other ways, provided the car e ment is disposed accordingly.

The car element Y, see 2. comprises a simila til-shaped core or yoke 7 of n aenetic material and is supported in some manner from the frame of the locomotive other vehicle, so as to pass directly over the track element T, as show in The air between the pole pieces of the track element T and the car element Y is pre eably made as shor' as equipment and 7 is a coil 8 conven'ently te coil and on the otherle oother coil 9, conveniently termed the secondary coil.

In connection with the car element tl pi'eierabl y employed an electron ampl "11g relay of the thermionic or vacuum bill) type, 1 an audion,

COll llllOlrly KHOWD 3.. and which will be referred to by that i aine as a matter of convenience. This audio eing welhknown in the art, is illustrated convennnprises a filament F, a grid n controls a car relay The notion of this relay adaptii a train control system ot the type shown in rnis no part or the present in S0 vcntion, and this relay is shown conventake may *arious ts pa ticular construction *1 the present invention, this rated convention device, shown in 'f'DQ JlC valve, may

i apply the brakes nor operr tron inn, t is necessz ry to provide the device *h are broken when said in the conventional lustrated in Fig. 2, the core or the device carries an insulated hich t. hle lined contacts conventioi ally is arrows) and thus A r L1 through said contacts i T 1 J- energized. (i hen tea t is 'e-en rghced, its core or plunger l by i air pressure or the like,

ement with .ied contacts. hereby brealt' rough said ontact;

ith the invention m nd a d ed 'o s. e

. T as t v ntior all Y r Jr r b so lLCll of is in erotectir 5 case r wi thout ut p rea:

' rangemont has been illustrated.

sistance of someone else, the purpose to g to make the operation of this reset switch Q so objectionable to the engineer that he Wlll voluntarily observe and obey the signals to avoid the necessity of such operation. The hold-oil switch or device H is arranged in the cab in a convenient position to be operatod by the engineer; and to prevent its improper manipulation, there is provided as-- sociated mechanism which prevents the device being held closed or fastened down. A holdo;ll' device of this character is disclosed in a generic form in the Howe application above mentioned, and it is to be understood that no claim is made here to the generic form of the invention disclosed in the said application.

The circuit connections between the audion, the relay R, and the control device K are sul ject to considerable modification in practice, but since any form of connections suitable for causing operation of the relay B when the car passes an active track element, is applicable to the present invention, only one typical ar- The lilanient F of the audion is heated by the battery A. 'l. he grid G is connected in circuit with the secondary coil 9 and the battery C by wires 38 and 39, so that electro-motiv, forces induced the secondary coil. will vary the grid potential. The plate P is connected in circuit with the relay li, a front contact there of, and the ba.;teries B and C. Referring to Fig. 2 this plate circuit may be conveniently traced as follows:com1nencing at the positive terminal. of battery B, wires 40, all, 42. front contact 4-3 of relay R, wires 4% and 4.5, relay R, and wire 46 to plate P.

The primary coil 8 is normally energized from batteries 13 and C through the train con trol. device K and the front contact 43 of the relay R, this circuit being traced as follows:commencing at battery B, wires 4.0, 4-1 and 42, front contact 4-3 of relay ll, wires l4c and 47, reset switch 11 and its closedcontact, wire a8, device K, wire 4C9, primary coil 8, and wire 51 to the battery C.

Operation.Tho battery C normally produces a positive potential upon the grid G with respect to the average potential. of the filament F, and thus permits current to How in the plate circuit and maintain relay R energized. The current through the primary coil 8 produces a magneto-motive-force tending to send flux through the car yoke 7, this flux passing in part tln-ough the l cgs of said yoke and in part through leakage paths. The yoke 7 may be said to constitute a partial magnetic circuit with an air gap of relatively high reluctance.

Assume that the car passes over track element T having its coils 6 open-circuited, corresponding to dangerous t *aiiic conditions ahad, that is, when a stopping impulse should be transmitted. The track element in this condition presents in effect a magnetic loop for theyoke 7 on the passing car, and acts to complete the partial magnetic circuit on the car and change its reluctance, the luctance decreasing from a normal to a minimum, and then baclr to normal, as the car approaches and recedes from the tracl: element. This change in reluctance vari the flux passingthrough the secondary coil 9, thereby inducing an electro-lnotive iiiorce in said coil, first in one direction and then in the other. One half of this wave of induced E. M. F. in the secondary coil 9, either the first or secon d half depending upon the connections, opposes the voltage of the battery C and reduces the potential on the grid G. The normal potential on the grid G being thus decreased, the current flowing in the plate circuit through the relay it is likewise decreased, and the parts are so proportioned and adjusted that the current in the relay ll is reduced in this way below the amount required to hold its front contact 43 closed. Vlhen the front contact opens, the "rain control device K is (lo-energized, and the circuit through relay R is also broken at its contact $3, with the result that said relay can not again pickup when the grid potential again becomes normal.

Suppose that the coils G of the track element '1 are included in a closed circuit of low resistance, corresponding to clear oraliic conditions. When the car element Y passes over a track element in this clear or inactive condition, the relay It is not operate b pause the coils 6 0n the track element oppose or choice back the passage oi flux through the yoke 5 due to the counter-elcctro-mohive-forces induced in said coils, with the result that there is little change in flux through the secondary coil 9 and the relay is not operated.

The operation so far described is that which is characteristic of the type of system illustrated, this particular systen'i being merely illustrative of one suitable for the application of the present invention, and being disclosed and claimed in other applications. Arrangements to prevent improper operation of the car equipment by track rails or other masses of iron along the track, and various other expedients that may be necessary or desirable in a complete system, are not material to the present invention, and being; fully disclosed in other applications, are not herein illustrated. Further, the operation so far described does not take into consideration the action of the hold-oil device H, the reset switch Q, and associated parts constituting the. subject-matter of the presentinvention.

As previously explained, the purpose of the present invention is to provide an ar rangement for enforcing vigilance on the part oi the engineer in observing and acting upon the indications of the fixed signals. T he engineer is supposed to watch out for the vaand it one of these sigis intended that he device E1 While racl: elen eni, t the c onar the 0,. it track e rra will not erite "he proper time, and piara us i: Will b 1 eration as the train rack element, thereby s ti on and construction is si by said apoaratus upon the cs maintain il the resetira swit ile only it. so in t he s ope 1 o? obiectio (ill nat i device in recosni-rio' signal, rather than he s" 'al trouble, annoyance, sting; the reset switch here that the penalty, l, i =0 s1 oak, and concurren ""i l naturally have more subsec u 59 a recorder or device n V conjanction with the system described to provide a check which the engineer ierfornis l i *ier' no t e arrangement e 1' pr *enting effecan arrange handle 12 of revents de-cne" ,1 ,1 J! c 1. u i t is iiont conthe hold-off device l-i, 5- normally closed contacts 10 ot' the device l wire su 11 and its closed contact, Wire ib, device l1, wire it, primary coil 8 and to battery C and b to battery ei'i'ect this circuit comprises in part a around the front eonta 43 of the reiay that although said front contact opens, ice K is n ntaiiied energized. if the engineer operates the hold-oi crevice H the Whistle i is sounded when the front ot' the relay R opens, said front ether with Wires ii, 42, i i and l'i' a low resistance shunt around portion comprising Wire 52, the tne Whistle V, 53, 25-2(i, 16 1S, nd depriving the winding of ective current until said i ont- 'i he whistle l thus serves 1 the track eleinent ha been the hold-oil device H may be :;o, the sounding of the Whistle 7 signifies seat the train control equipment 'orl' ng properly, and that an automatic A i the device K would have occurred if the hold-off device had not been ed. When the relay R opens its front this contact Will be at once closed as i s the nor nal current again flows in the circuit, because the front contact of 1 through the Whistle VJ, the Winding of the whistle il being made in practice oi low enough resistance to permit the relay R to pick-up with said Winding i1 series therewith.

It the engineer does not operate the hold-o device H at the proper time, the relay R drop. and (lo-energizes the device K, imposing tile desired control upon the train, and also opens the contacts 10 or" said device so that subsequent operation of the hold-oil device H is not eiiective to restore the relay R. The relay E- can only be restored by operating" the reset switch ran the reset switch C5 is actuated to close its normally opened contacts, tie relay R is energized by cir uit which may be traced as tollowszcoinn encinr;- at the batte B, Wires d0, 4&1 and 56, switch 11, Wires i7 and 45, relay R and Wire to the )l te i. Yihen relay is thus picked up, t is held up t irough its own frontcontact 43 and toe switch Q may be restored to normal.

It Will be noted that when the switch G is ted, ithrealzs the energizing circuit for rice K, so that unless restored to the 1 position, the train is not released from he control imposed by the device ii. Thus, l reset switch Q is protected against ini- =ope: manipulation, and can not be fastened owi, otherwise the train control device K will be operated and prevent the usual train movement.

In the form shown in Fig. 2, the normally closed contacts 25*26 of the hold-oil device H are included in the wire 53 of the hold-0d circuit and are also included in series wito the normally opened contacts 16-18 of said liolrho'lt device. 'llhe cam 22 of this acknowlin, device T iioscdii'iacloclm'iscdirectie 1, but is held nst rotation by the pin thereof ei ie handle 12, the spring 15 to overcome the fierce it the handle 12 is held down, the cam 22 rotates in a clocl=:wir-:o direction at a restricted rate determined by a suitable time controlled device, more specifically described in the parent application. if the engineer holds down the handle 12 too long, the contacts 2526 open, for r isons apparently from the shape oi the cam 22, rendering the device H ineii'ective and causing automatic operation of the device K at the next active track element T. In other words, while the engineer may fasten down the handle 12 otthis hold-oii device without immediate penalty, this act will the same time destroy the effectiveness or. said holdso'l l device and consequently maize it useless to fasten down the handle '12. In short, the engineer must operate the hold-oil device at each signal and at the time he is passing that signal, otherwise anautomatic operation of the train control device K will result.

3 shows a modified. arrangement of the parts and circuits constituting the invention, in which the operation of the hold-oil device H prevents effective action of the cautionary impulse by maintaining the Control relay R energized. .ln this modified arrangement, when the handle 12 is moved down and contacts 1618 are closed, the relay R ma; he maintained ene'ai izaed independently of the decrease in our] art between the plate and jtilament of the aud on by an auxiliary energizing circuit follows: commencing at an in tcrmcdiate tap oi? the battery I wire 70, adjustable resistance 71, wire 72, contacts 1ti-1S. wire 73, contacts 25 and 26, wire 7435, relay R, wires 42:; and 44, front contact 43, wires 42 and. 40 to the end tap oi? the battery he voltage of the section of the battery 7% inchided in this circuit, together with the resistance 71, is proportioned with. regard to the resistance o1 the audion between the plate and filament, so that the current supplied to the relay R corresponds substantially with its normal Wei-lung current when governed. by the audion.

The modified circuit arrangement shown in Fig. 8 has the same general. characteristics of operation that have been descriliied. As the eer approaches caution signal, he may down the 12 and clc e contacts i, trom *a over a coherent form of holdiwwledg einent arrangement is provided. in Fig. 3 the elements 52, XV, 53, 54, i0 and of the hold-oil moans shown in Fig. 2 ha ve been omi'i'iitted, and the normally closed contacts L526 and the normally opened contacts 16 18 of the hold-oil device H have tween emiloyed to provide a distinct circuit for maintaining the relay R energized irrective otthe action of the amplyfying device F, i i, if upon passage oi a train by a control poi t. will he noted that upon operation of? the handle 12 and for a predetermined led at time thereafter both pairs of concts l6 and 25 26 are closed, and the mine hold-oil circuit is completed:-

at the plus side of battery B, wires ell.) and 42, contact 13, wire 4.4:, winding of relay ll, wire fl57el, contacts 26-25, Wire 73, contacts 1816, wire 72, resistance 71, wire back to the midpoint of battery B. The closure of this circuit maintains the relay R energized even though the plate circuit in the amplifier drops to zero.

This mooified form of Fig. 3 has its normally closed contacts 2526 included in series with its normally open contacts 1618, similar to the arrangen'ient shown in Fig. 2 of this application, and except for the change of location of the normally closed contacts 25-26 this modified form (Fig. 3) is the same as original Fig. 8 of the parent application.

Having thus shown and described my invention, it is to he understood that my invention is not limited to the specific arrange ments shown and described.

ii hat I claim isz 1. In an automatic train control system, an electromagnetic brake control device on a vehicle, a relay governing said device, traflic controlled means 'for controlling the relay, and n'ianually operable means adapted to prevent operation of the relay and having a limited time of etl'ective operation, such means includin normally open and normally closed contacts in series.

In a train control system; cooperating (rack and car-carried elements a device for applying the car brakes when initiated; stick control ing means for initiating said device 'ail'e luences til closed contacts in series with each other, operable to prevent the said affecting ot' the controlling means by said trackvay influences, said acknowledging means including means automatically operable after a predetermined time interval from operation thereof, to cause opening of the normally closed contacts; and reset means, When operated, initiating said device and closing a pick up circuit for said stick controlling means.

3. In an auton atic train control system of the irermittent inductive type, the combination with a control relay on the car connected 1 a stick circuit including its ovvn front contact, of tracl-Ivvay means at spaced control points the traclixvay tor inductively through an intervening air gap die-energizing said control relay upon passage of said car under adverse tra'liic conditions, an acknowledging device including normally closed and normally open contacts constructed when operated to close the normally open contacts immediately and open the normally closed contacts a predetermined interval of time after such operation, and a shunting circuit for preventing said traclnvay means de-encrgizing said control relay including said normally open contacts said normally closed contacts and a signal in series, whereby said signal is rendered active upon the reception of control influence from the traclrWa-y and said control relay is maintained energized it said ac lnon'ledgin device has been operated.

In testimony whereof I atiiX my signature.

oneness s. BUSHNELL.

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