US1767578A - Automatic train-control system - Google Patents

Description

' June 24, 1930. c. s. BUSHNELL 1,767,573

' AUTOMATIC TRAIN CONTROL SYSTEM Filed May 18. 1921 {Sheets-Sheet '1 FIG.1. 2 H 1 j z On Track June 24, 1930.. c, s, BUSHNELL 1,767,578

1 AUTOMATIC TRAIN CONTROL SYSTEM Fild May 18, 1921 5-Sheets-$heet 2 7 r 46 5 4"/ (Lu- E5 mnm li n/15 W MTTORNEY.

June 24, 1930. B H L 1,767,578

AUTOMATIQTRA IN CONTROL SYSTEM Filed May 18, 1921 3 Sheets-Sheet 3 Patented June 24, 1930 UNITED STATES PATENT OFFICE CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF GATES, NEW YORK, ACORPOBATION OF NEW YORK AUTOMATIC TRAIN-CONTROL SYSTEM Application filed May 1a, 1921. Serial No. 470,592.

This invention relates to automatic train control systems for railroads, and more particularly to the car equipment of such systems.

When a system of automatic train control is applied to a train, there is a natural tendency or the engineer to rely upon this system. If the engineer has confidence in the proper performance of the automatic apparatus, he may perhaps be more lax in his observance 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 vigil ance of the engineer, because modern block signal systems are very reliable and efiicient, and engineers as a rule are highly trained, experienced andcareful 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 system and the care with which the engineers ordinarily observe and obey the signals. It is evident that the ultimate safety of the train is increased if the automatic train control system is supplementary to the block signal system and the vigilance of the engineer, rather than as a substitute therefor; and if the engineer can be encouraged or forced to observe and act upon the indications of the trackway signals, a serious accident can result only when signal system, the enineer and the train controlapparatus all fail at the same time. I

With these considerations in mind, one object of the present invention is to provide a system of automatic train control in which a suitable penalty is automatically enforced if the engineer fails to observe a caution or stop signal, and fails to take some appropriate action in recognition of such unfavorable signal indication. If the engineer observes this indication and acts accordingly, the penalty will. not be enforced; and the engineer is thus encouraged to observe and act upon the signal indications. According to the present 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 oper* ated. This reset device is preferably made accessible only from the ground or is arranged in some other way so that it can not be used Without great trouble and annoyance, and is also protected so that it can not be maliciously fastened down, or manipulated in a way as to avoid the penalty and defeat the purposeof the invention.

This invention is in the natureof an improvement upon the system disclosed and claimed in the application of WV. K. Howe, Ser. No. 47,110, filed July 30, 1925; and the patent to Howe No. 1,551,515, dated August 25, 1925.

In the accompanying drawings, Figure 1 is a diagrammatic view of one arrangement of trackway circuits applicable tothe present invention;

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

Figs. 3 to 5, inclusive, illustrate modified wiring arrangements and constructions of the car equipment; and

Fig. 6 is a perspective view, with parts broken away, spread apart and shown in section for the sake of clearness, which illustrates one suit-able form of the protected holdofi device.

Referring to Fig. 1, the track rails 1 of the railroad track are dividedby insulated joints 2 into blocks in the usual way, one block N with the adjacent ends of two other blocks M and 0 being shown. The parts and circuits associated with the several blocks are the same, and for convenience these will be given like reference characterswith distinctive exponents. Each block is provided with the wellknown normally closed track circuit commonly used in block signal systems, comprising a track battery 3 and a track relay 4. The usual tra ckway fixed signals S are illustrated convention ally, and since theymay take various forms, such as semaphore signals or color light signals, and may be controlled in any of the well-known ways, no attempt has been made to illustrate their control circuits and devices, it being understood that these signals will give the usual clear, caution, and stop indications and will be obeyed in accordance with the rules in force on the particular railroad.

In the particular embodiment of the invention illustrated, it is assumed that the transmission or communication of the desired controlling impulses or influences from the trackway to the moving trains for governing the automatic apparatus thereon in accordance with traffic conditions, is accomplished inductively, that is, through an intervening air gap. IVhile this inductive type of impulse transmittin means may take any one of various well-known forms, there is illus trated an arrangement comprising a track element T.

The track element T comprises in general a Ushaped yoke or core 5 of magnetic material, with coils 6 thereon. The coils 6 are wound and connected in series in such a way that the electro-motive-forces generated in the. respective coils by flux passing through the yoke 5 are cumulative or additive. These track elements T may be located and controlled in various ways, dependent upon trafiic conditions ahead, but in the particular arrangement shown in Fig. 1, a track element T is located at the entrance to each block, a hort distance in the rear of the insulated joints 2, the normal direction of traffic 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 i of the corresponding block, and a front contact of the track relay 4 of the 'iext block in advance. Thus, the coils 6 of the track element T at the entrance to a given block are in a closed circuit under clear traflic conditions, but are open-circuited under caution or stop conditions, that is, when the rel-responding block or the next block in advance is occupied. These track elements T may be located crosswise of the track between the track rails as shown, or lengthwise, between or outside of either track rail, and in ther ways, provided the car element is dis posed accordingly.

The car element Y comprises a similar U- shaped core or yoke 7 of magnetic material and is supported in some suitable manner from the frame of the locomotive or other vehicle, so as to pass directly over the track element T, as shown in Fig. 2. The air gap between the pole pieces of the track element T and the car element Y is preferably made as short as equipment and roadway clearances will permit. On one leg of the yoke 7 is a coil 8, conveniently termed the primary coil, and on the other leg of said yoke is another coil 9, conveniently termed the secondary coil.

In connection with the car element Y, there is preferably employed an electron amplifying relay of the thermionic or vacuum bulb type, commonly known as an audion, and which will be referred to by that name as a matter of convenience. This audion, being well-known in the art, is illustrated convenitnoally, and comprises a filament F, a grid G and a plate P.

The audion controls a car relay R. The features of construction of this relay R adapting it for use in a train control system of the type shown form no part of the present invention, and this relay is shown eonventionally.

The train control apparatus, which acts to apply the brakes or in some other way govern the train with safety, may take various forms, and since its particular construction forms no part of the present invention, this apparatus has been illustrated conventionally as a device K. This device, shown in the form of an electro-pneumatic valve, may act to vent the train pipe and apply the brakes directly, or govern the operation of some other form of speed regulating or brake controlling mechanism. This device K is normally energized, and is set into operation when deenergized. In connection with certain forms of the invention, it is necessary to provide the device K with contacts which are broken when said device is deenergizcd. In the conventional construction illustrated, the core or plunger of the device K carries an insulated disc 10 which engages suitable fixed contacts (shown conventionally as arrows) and thus completes a circuit through said contacts when the device K is energized. IVhen the device is deenergized, its core or plunger is moved by a spring, air pressure or the like, to move the disc 10 out of engagement with its cooperating fixed contacts, thereby breaking the circuit through said contacts.

In connection with the invention there is preferably employed a suitable cab si nal or indicator, and while this indicator may be a light, bell, or the like, it has been illustrated as an electrically controlled air whistle W. which constructed so to sound the whistle when its controlling magnet is energiz d.

The reset switch or button Q is shown convent-ionally as spring plate or key 11 which normally engages a fixed contact and can be moved from engagement therewith against another contact. This reset switch Q is in practice enclosed in a suitable protecting casing, which may be sealed or locked, or placed so as to be accessible only from the ground, or in some other way arranged so that it can not be operated by the engineer without bringing the train to a stop, or without a great inconvenience, or without calling in the assistance of someone else, the purpose being to make the operation of this reset switch Q so objectionable to the engineer that he will voluntarily observe and obey the signals to avoid the necessity of such operation.

The hold-off switch or device H is arranged in the cab in a convenient position to be operated by the engineer. The function of this hold-off device H is to close certain contacts, when it is operated by the engineer; and to prevent its improper manipulation, there is provided associated mechanism which prevents the device being held closed or fastened down. A hold-off 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. I

One suitable form of a hold-01f device H is shown in a diagrammatic manner in Fig. 6,

Y and comprises ahandle .12 loosely mounted on a shaft 13 suitably supported by the side plates 14 of the mechanism. The handle 12 is urged upward by a spring 15. A pair of contact springs 16 are supported on the block 17 of insulating material fastened to'the base or frame of the mechanism. These springs 16 may be bridged by a contact piece 18 carried by an insulating block 19 which is attached to the lower end of a plunger 20. The plunger 20 is guided in a suitable lug or bracket 21, and is connected by a pin and slot connection at its upper end to the handle 12. Fixed to.

the sha 13 is a cam 22 carrying a pin 23 engaging the upper edge of the lever 12. On this cam rests a roller carried by a pivoted arm 24. This arm 24 carries'an insulated contact piece 25 which normally bridges a pair of contact springs 26 secured to a fixed block 27 of suitable insulating material. The shaft 13 is urged in the clockwise direction by a clock spring 28, the action of this spring upon the shaft 13 being less than that of the spring 15. A ratchet 29 is fixed to the shaft 13 and cooperates with a spring-pressed pawl 30 on a gear 31, so that the gear is driven when the shaft 13 is turned by the spring 28 in a clockwise direction. 1 The ear 31 drives a pinion 32 secured to a sha 33; and on the shaft 33 is an escapement wheel 34 which cooperates with an oscillating weighted pallet 35. This pallet 35is rovided with holes by means of which addi ional weights may be attached.

The normal position of the parts of the hold-offdevice H is that shown in Fig. 6. When the engineer presses down the handle 12, against the opposition of spring 15, the

contact piece 18 engages contact springs 16 and completes a circuit, hereinafter described, which prevents efiective operation of the train control apparatus. During this movement of the handle 12, it is moved down away from pin 23, freeing the cam 22 and shaft 13, and permitting said shaft to be driven by spring 28 in a clockwise direction at a speed determined by the pallet 35 cooperating with the escapement wheel 34. When the shaft 13 has been turned by the spring 28 through a certain angle, corresponding to the lapse of some selected time, the cut away portion of the cam 22 comes underneath the roller on the arm 24, allowing said arm to drop by its own weight, aided by the resiliency of the contact springs 26, thereby disengaging the fixed contact 25 from said contact springs 26 and interrupting the circuit through said contacts. If the handle 12 is released before the lapse of the time interval for which the device is adjusted, the spring 15 restores said handle to its upper position and carries with it the pin 23, cam 22, and the shaft 13, thereby restoring the parts of the timing mechanism into their initial condition. It will be observed that the hold-off device H comprises in general: a handle 12, normally open contacts which are closed when the handle is shifted to its working position, normally closed contacts, and associated time controlled mechanism, which causes opening of the normally closed contacts when the handle 12 is held down for more than a certain predetermined time.

The circuit connections between the audion, the relay R, and the control device K are subject 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 arrangement has been illustrated. The filament F of the audion is heated by the battery A. The grid G is connected in circuit with the secondary coil 9 and the battery C by wires 38 and 39, so that electro-motive forces induced in the secondary coil will vary the grid potential. The plate P is connected in circuit with the relay R, a front contact thereof, and the batteries B and C. Referring to Fig. 2 this plate circuit may be conveniently traced as follows: commencing at the positive terminal of battery B, wires 40, 41, 42, front contact 43 of relay R, wires 44 and 45, relay R, and wire 46 to plate P.

The primary coil 8 is normally energized from batteries B and C through the train control device K and the front contact 43 of the relay R, this circuit being traced as follows: commencing at battery B, wires 40, 41 and 42, front contact 43 of relay R, wires 44 and 47 reset switch 11 and its closed contact, wire 48, device K, wire 49, normally closed contacts 2526 of the hold-off device H, wire 50, primary coil 8, and wire 51 to the battery C.

Operatz'0n.-The battery C normally proyoke '7 may be said to constitute a partial magnetic circuit with an air gap 0'? relatively high reluctance.

Assume that the car passes over a track ele ment T having its coils open-c' cuited, corresponding to dangerous trallic conditions ahead, that is, when a stopping impulse should be transmitted. The track element in this condition presents in eflcct a magnetic loop for the yoke 7 on the passing car, and acts to complete the partial magnetic circuit on the car and change its reluctance, the reluctance decreasing from a normal to a minimum, and then back to normal. as the car approaches and recedes from the track cle- 3 ment. This change in reluctance varies the flux passing through the second I coil 9, thereby inducing an electro-motivc-force in said coil, first in one direction and then in the other. One half of this wave of induced M. F. in the secondary coil 9, either the first or the second half depending upon the connections, opposes the voltage of the battery C and reduces the potential on the grid The normal potential on the grid G being thus decreased, the cu rent flowing in the plate circuit through the relay R is likewise decreased, and the parts are so proportioned and adjusted that the current in the relay R is reduced in this way below the amount required to hold its front contact 43 closed. When the front contact opens, the train control device K is deenergized, and the circuit through relay R is also broken at its contact 41-3, with the result that said relay can not again pick-up when the grid potential again becomes normal.

Suppose that the coils 6 ot the track element T are included in a closed circuit of low resistance. corresponding to clear traific conditions. lVhcn the car element Y passes over a track element in this clear or inactive condition, the relay R is not operated, because the coi s 6 on the track element oppose or choke back the passage of flux through the yoke due to the counter-electro-motiveforces induced in said coils, with the result that there is little change in flux through the secondary coil 9 and the relay not operated.

The operation so far descr bed is that which is characteristic of the type of system illustrated, this particular system 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 describe-cl does not take into consideration the action of the hold-oft device H, the reset s 'itch Q. and associated parts constituting the subjcctmatter of the present invention.

As previously explained, the purpose of the present invention is to provide an arrangement for enforcing vigilance on the pa it of the engineer in observing and acting upon the indications of the fixed signals. The engineer is supposed to watch out for the various fixed signals S, and it one of these signals indicates caution, it is intended that he should operate the hold-otl' device H while passing the corrcspoiuling track element T, this act being in recognition of the cautionary indication of the signal and an acknowledgment that there is another train a short distance ahead. It assumed that if the engineer makes such a positive movement, he fully appreciates the existence of danger and may be relied upon to slow down the train or take such action as is necessary to avoid a collision.

Consequently, if the engineer is alert and operates the hold-oft device at the proper time in recognition of a caution signal, it is unnecessary to take the control of the train out of his hands or apply the brakes at once; and the preferable arrangement of circuits is such that timely operation of the hold-oil device H prevents, in some of the ways hereinafter described, the effective action of the track element upon the train control device K. It the engineer is not alert, however,'and due to negligence or any other cause fails to see or read correctly the signal indications, he .will not operate the hold-0ft device atthe proper time, and then the train control apparatus K will be automatically set into operation as the train passes over the active track element, thereby slowing down the train and avoiding a collision. Further, the construction is such that the control exerted by said apparatus upon the train will be maintained until the reset switch Q is operated. If this reset switch Q is accessible only from the ground, so that the train must be stopped before it can be actuated, or if operation of this switch is made difiicult or objectionable in some other way, the engineer will naturally prefer to operate the hold-off device H in recognition of each caution signal, rather than be subjected to the special trouble, an-

noyance, or publicity of actuating the reset switch Q. It may be noted here that the penalty, being self-inflicted, so to speak, and concurrent with the default, will naturally mam have more influence than any subsequent discipline, although it is evident that a recorder or similar device may be used in conjunction with the system shown and described to provide a check upon the way in which the engineer performs his duties. I

Referring now to the specific arrangement of circuits and devices for preventing efi'ective action of an active track element upon the train control device K when the hold-01f device H is properly operated, and for imposing a penalty when such device is not properly operated, Fig. 2 shows an arrangement in which operation of the handle 12 of the hold-off device H to close contacts 16-18 establishes a circuit which revents deenergization of the device K w en the front contact 43 of the relay R opens. This hold-off circuit may be traced as follows: commencing at battery B, wires 40 and 52, whistle W, wire 53, contacts 16-18, wire 54, normally closed contacts 10 of the device K, wire 55, switch 11 and its closed contact, wire 48, device K, wire 49, normally closed con tacts 2526 of the hold-off device H, wire 50, primary coil 8 and wire 51 to the battery C. In efliect this circuit comprises in part a shunt around the front contact 43 of the relay R, so that although said front contact opens, the device K is maintained energized.

If the engineer operates the hold-off device H the whistle W is sounded when the front contact 43 of the relay R opens, said front contact, together with wires 41, 42, 44:

and 47 constituting a low resistance shunt around the winding of the whistle W and depriving it of effective current until said front contact opens. The whistle W thus serves to indicate that the track element has been passed, and that the hold-ofl device H may be released. I Also, the sounding of the whistle W signifies that the train control equipment is Working properly, and that an automatic operation of'the device K would have occurred if the hold-01f device had not been operated. When the relay R opens its front contact, this contact will be at once closed as soon as the normalcurrent again flows in the plate circuit, because the front contact of said relay is shunted by the holdo'tf contacts 16--18 through the whistle W, the winding of the whistle W being made in practice of low enough resistance to permit the relay R to pick-up with said winding in series therewith.

If the en user does not operate the holdoff device at the proper time, the relay R drops and deenergizes the device K, imposing the desired control upon the train, and also opens the contacts 10 of said device so that subsequent operation of the hold-ofi' device H is not effective to restore the relay R. The relay R can only be restored by operating the reset switch Q. When the reset switch Q actuated to close its normally opened contacts, the relay R is energized by a circuit which may be traced as follows: commencing at the battery B, wires 40, 41 and 56, switch 11, wires 47 and 45, relay R and wire 46 to the plate P. When relay R is thus picked up, it is held up through its own front contact 43 and the switch Q may be restored to normal. I

' It will be noted that when the switch Q is actuated, it breaks the energizing circuit'for the device K, so thatunless restored to the normal position, the train is not released from the control imposed by the device K. Thus, the reset switch Q is protected against improper manipulation, and can not be fastened down, otherwise the train control device K will be operated and prevent the usual train movement. Similarly, the hold-off device H is protected against improper manipulation, because if the handle 12 is fastened or held down too long, the normally closed contacts 2526 open and deenergize the device K. The time-controlled mechanism associated with the hold-off device H is adjusted to afford the engineer all reasonable latitude in operating the handle 12', as he passes a signal or control point, but this time interval is preferably made short enough to prevent the engineer getting by two caution signals in succession by one operation of the handle 12.

Fig. 3 shows the same arrangement of circuits'as Fig. 2, except that the normally closed contacts 2526 of the hold-off device, instead ofmerely deenergizing the train control device K when they open, also break the circuit for energizing the relay R. This inflicts a more severe penalty. for holding down the handle 12 too long, since the reset switch Q must then be operated to restore the relay R; whereas in the arrangement shown in Fig. 2, it is merely necessary to restore thehold-oif device H in order to proceed.

In the modified arrangement shown in Fig. 4, the normallyclosed contacts 25-26 of the hold-off device H are included in the grid circuit, and when these contacts open due to improper manipulation of the handle 12, the relay R is dropped and the train control device K is set into operation. In this arrangement, like that shown in Fig. 3, the parts must be restored by operation of the reset switch Q before the train can proceed.

Fig. 5 shows a still further modification in which the relay R is allowed to drop at each caution signal, but the train control device may be kept from operating by timely manipulation of the hold-off deviceH, provision being made to penalize the engineer for failure to make such timelyoperation, and also for protecting the hold-off device against improper use. In this modified arrangement, the relay R is included directly in the plate circuit of the audion, and the energization of said relay does not depend upon its own front contact 43, as in the embodiments of the invention previously discussed. The reset switch Q is provided with two different plates or switch members 75-76, one normally engaging a contact, and the other engaging a contact when said switch is actuated. The train control device K is normally energized by a circuit that may be traced as follows: commencing at the positive terminal of battery B, wires a and 12, front contact 43 of the relay R, wire l7, normally closed contact T5 of the reset switch Q, wires 77 and 78, device K, wires 79 and 80, contacts of said device, wire 81, normally closed contacts -26 of the hold-off device, wire 50, primary coil 8, and wire 51 to the negative terminal of battery C. When the handle 12 is pushed down and contacts 16--18 are closed, the train control device K, if energized at the time, may be maintained energized, regardless of the opening of the control relay R, by a circuit which may be traced as follows: commencing at the positive terminal of the l attery B, wires and 82, contacts 16-18 wires 83 and T3, device K, wires 79 and 80. contacts 10 of device K, Wire 81, contacts 2526, wire 50, primary coil 8 and wire 51 back to the negative terminal of battery C. Thus, if the engineer makes timely operation of the hold-01f device, that is, before th relay R is deenergized by the passage of the car element Y over a track element T in the active stopping condition, he may prevent operation of the train control device K.

If the engineer does not operate his holdoff device in time, the train control device K is deenergized and must be restored by a special manipulation as follows. The fireman or other person has to hold down the reset switch Q, and the engineer has to throw down the handle 12 to close contacts 16-18, whereupon a pick-up o1 restoring circuit for energizin g the device K is established, said circuit being traced as follows: commencing at the positive terminal of battery 13, wires 40 and 82, contacts 1618, wires 83 and 78, device K, wires 79 and Set, switch 76 closed, wire 85, contacts 2526, wire 50, primary coil 8, and wire 51 back to the negative terminal of the battery C. This circuit energizes the device K and recloscs its contacts 10. The reset switch may then be restored to normal, the device K being maintained energized through the regular hold-off circuit previously traced through contacts 1618; and with the switch closed, the circuit for normally energizing the device K through the front contacts 43 of he relay P. is set up, so that the handle 12 LL may now be released and returned to the normal position.

In this modification shown in Fig. 5, the reset switch Q can not be fastened down, because in so doing the normal energizing circuit for the device K is broken and said device will be dccncrgized, unless its hold-01f circuit including contacts 25-26 and 1(Jl8 is then established. This hold-off circuit, however, can not be maintained for any length of time, be 'ause if the handle 12 is held down to keep contacts 1618 closed, the contacts 25-26 will open after the short time for which the timing mechanism associated with the handle 12 is adjusted. Consequently, any attempt to fasten down either the reset switch Q, or the handle 12, will eventually result in operation of the train control device K, requiring its restoration by the joint action of two persons. This arrangement imposes a penalty upon the engineer for failure to observe the signals and make timely operation of the holder-off device, and also for misuse of the hold-off device, the restoration of the train control device K in both cases requiring the cooperation of two persons.

Vhile only one hold-off device H has been illustrated in the various embodiments of the invention, two of these devices may be used, if desired, one for operation by the engineer, and the other by the fireman. Such an ar rangement would then require the cooperation of both the fireman and engineer to get by a caution signal without having the train control apparatus set into operation. Two hold-off devices used in this way serve to notify the fireman as well as the engineer that the train has passed a caution signal, and it is contemplated that the fireman will aid the engineer, and in fact bring about stopping the train itself in case the engineer neglects: to do so. In other words, knowledge that the train has entered a danger zone is given to two persons intsead of only one, thereby assuring that there must be a double man failure before an accident can occur.

Having thus shown and described :-several embodiments of my invention, it is to be understood that my invention is not limited to the specific arrangements shown and described.

What I claim is 1. In an automatic train control system. a brake control device on a vehicle. a normally energized stick relay controlling said device, means partly on the vehicle and partly' on the track causing deenergization of the relay under dangerous traflic conditions. and manually operable means for preventimc op eration of said device upon deeuergization of the relay, said manually operable means if maintained in its operating condition for more than a predetermined time acting to actuate said brake control device. I

2. In an automatic train control system, a brake control device on a vehicle, a normallv energized stick relay controlling said device. means partly on the vehicle and partly on the track causing deenergization of the relay under dangerous trallic conditions, manually controlled means having a limited time of elfective operation for maintaining said brake control device inactive regardless of the deenergization of said relay, and means,

manually operable means being effective only if actuated prior to the deenergization of said relay.

4. In a system for automatically controlling railway vehicles, the combination with train control apparatus'on a vehicle, of, a normally energized stick relay for controlling said apparatus, means for momentarily breaking the energizing circuit of said relay at each caution signal, and manually operable means for preventing operation of said apparatus upon deenergization of the relay and for simultaneouslyrestoring the relay to normal, said manually operable means having a limited time of eflective operation. Q I

5. In an automatictrain control system, a brake control device on a vehicle, a normally energized stick relay controlling said device, means partly on the vehicle and partly on the track causingdeenergization of the relay under dangerous trailic conditions, manually operable means adapted-to be effective for a limited time only and acting when operated to render said brake control device ineffective regardless of the deener ization of the relay and also to re-energize t e relay, said means bein ineffective when the brake control device.1s active, and other manually operable means for. restoringthe relay to normal.

6, In an automatic train control system for railroads, the combination with a normally energized brake control device on a vehicle,- of a normally energized stick relay forcon trolling said device and having a pick-up cir' cuit and a stick circuit, traflic controlled means partly on the vehicle and partly on the track for temporarily decreasing'the current in said circuits, and manually operable means for controlling the pick-up circuit of the relay, said manually operable means acting to deenergize said brakecontrol device it maintained in the active condition longer than a predetermined time.

7 In an automatic train control system, the combination with a brake control device on a vehicle, of a relay controlling said device, traflic controlled means for governing said relay, manually operable means for maintaining said device inactive independent of its control by the relay effective if and only if it is operated prior to the operation of said relay, said manually operable means having a limited time of effective operation, and signaling means actuated at the time the relay is operated.

- 8. In an automatic train control system, the combination with a brake control device on a vehicle, of a relay controlling said device, traffic controlled means partly on the vehicle and partly on the track for causing deenergization of the relay under dangerous trafiic conditions, manually operable means for maintaining said device inactive while permitting operation of the relay, and for restoring the relay, and signalling means for indicating when the relay is deenergized.

9. In an automatic train control system, the combination with the brake control device on a vehicle, of an energizing circuit therefor, a relay for breaking said circuit, an auxiliary energizing circuit for said device, manually operable means for closing the auxiliary energizing circuit, and signalling means actuated when said relay is deenergized providing said auxiliary circuit is closed.-

10. In an automatic train control system, brake control apparatus on a vehicle, control means on the vehicle for said apparatus influenced from the trackway at each caution signal, manually operable means under the control of the engineer for preventing operation of said apparatus independently of its control by the control means while permitting response of said control means to the trackway influence, and automatic means for indicating to the engineer when the control means is actuated, said manually operable means having a limited time of effective op eration.

11. In an automatic train control system, a normally energized brake control device on a vehicle, a stick relay governing said device, means partly on the vehicle and partly on the track for causing deenergization of the relayunder dangerous traffic conditions, and manually operable means adapted when active to maintain the brake control device energized and to govern the energization of the relay, said manually operable means being ineffective when the brake control device is deenergized.

12. In an automatic train control system, the combination with normally energized brake control apparatus on avehicle, a normally open auxiliary energizing circuit for said apparatus, of manually controlled means for preventing operation of said apparatus by closing said circuit, said means eing automatically rendered inefl'ective by the opening of said circuit after a limited time following its initial operation, and a signal included in said circuit and operated by the flow of current therein.

, 13. In an automatic train control system, a

normally energized brake control device on a vehicle, a stick relay governing said device and having a pick-up circuit and a stick circuit, traiiic controlled means partly on the vehicle and partly on the track for temporarily decreasing the current in both the pickup circuit and stick circuit of the relay, and manually operable means for maintaining the brake control device energized and for closing the pick-up circuit of the relay.

1a. In an automatic train control system, a normally energized brake control device on a vehicle, a stick relay governing said device and having a pick-up circuit and a stick circuit, tratlic controlled means partly on the vehicle and partly on the track for temporarily decreasing the current in both the pick-up and stick circuits of the relay, a circuit controller in the pick-up circuit opened when the brake control device is deenergized, and manually operable means for cloisng said pick-up circuit at another point.

15. In an automatic train control system, a normally energized brake control device on a vehicle, a stick relay governing said device and having a pick-up circuit and a stick circuit, tra'llic controlled means partly on the vehicle and partly on the track for temporarily decreasing the current in both the pick-up and stick circuits of the relay, and manually operable means effective only when the brake control device is energized for maintaining said device energized and for establishing the pick-up circuit for the relav.

16. In an automatic train control system, a normally energized brake control device on a vehicle, a stick relay governing said device and having a pick-up circuit and a stick circuit, trafiic controlled means partly on the vehicle and partly on the track for temporarily decreasing the current in both the pick-up and stick circuits of the relay, manually operable means having a limited time of efl'ective operation for closing the pickup circuit of the relay at one point, and means for breaking said pick-up circuit at another point when the brake control device is deenergized.

17. In an automatic train control system, brake control apparatus on a vehicle, a stick relay influenced from the trackway dependent upon traflic conditions and governing said apparatus, said stick relay being temporarily deenergized at each caution signal and remaining deen rgized until restored, a restoring circiut for the relay, and manually operable means eiiective only if said apparatus is in its normal inactive condition tor establishing the restoring circuit for a limited time.

18. In an automatic train control system for railway vehicles, brake control apparatus on the vehicle having an energizing circuit, traiiic controlled means partly on the vehicle and partly on the track for interrupting said energizing circuit, a normally open auxiliary maintaining circuit including the brake control device, a normally inactive signal in said maintaining circuit rendered active b the flow of current therein, manually opera le means for closing said maintaining circuit at one point, and means responsive to the operation of the brake control device for interrupting the auxiliary circuit at another point when said device is operated.

19. Car equipment for automatic train control systems comprising a normally inactive brake control apparatus, a relay governing said apparatus, a manually operable hold-off device which if operated prevents operation of said apparatus, and time controlled means set into operation when the hold-off device is operated for actuating the relay after a lapse of an interval of time.

20. A manually operable hold-oil device, for train contro systems comprising normally open and normally closed contacts, a handle for quickly closing the open contacts, and clockwork mechanism set into operation when the handle is shifted to close the )en contacts for opening the closed contacts aiter an interval of time.

21. A manually operable hold-off device for train control systems comprising normally open and normally closed contacts, biased manually operable means for closin the open contacts, and spring actuated c 001(- work mechanism adapted when run down to open the closed contacts, said mechanism being automatically wound up and released as the manually operable means is restored to normal and shifted to close the open contacts respectively.

22. Train control apparatus for railway vehicles including a brake control device, a stick relay influenced from the trackway in accordance with trafiic conditions for governing said device, manually controlled means eflective to prevent operation of the device and to cause re-energization of the relay if actuated prior to the control of the relay from the trackway, and other manually operable means for restoring the relay, said last mentioned means acting when operated to set the brake control device into 0 eration, whereby the restoring means can not e maintained in its restoring condition.

23. Train control apparatus for railway vehicles comprising a brake control device, a. normally closed energizing circuit for said device, a stick relay influenced from the trackway in accordance with traflic conditions for interrupting said circuit, means effective only while the brake control device is energized and operable manually to maintain said device and also to restore the relay, and resetting means for restoring the relay and acting when operated to break said energizing circuit, whereby the resetting means can not be maintained in its resetting condition without causing operation of the brake control device.

24., Train control apparatus for railway vehicles comprising a brake control device having an energizing circuit, a stick relay governing said energizing circuit, and a reset switch operable to restore the relay, said switch when operated breaking saidlenergizing circuit.

25. In an automatic train control system, automatic brake control apparatus on a vehicle adapted to be governed from the trackway in accordance with traffic conditions, a normally closed control circuit for said apparatus, a stick relay adapted when energized, to maintain said apparatus in its inactive condition, a pick-up circuit for said relay, and a reset switch operable to close the pick-up circuit and at the same time break said control circuit.

26. In an automatic train control system, the combination with brake control apparatus on a vehicle operable to act on the air brake system of the vehicle to produce an automatic brake application, control means on the vehicle governing said apparatus, traific controlled trackway means and vehicle-carried receiving means cooperating inductively through an air-gap under danger traffic conditions to operate said control means, a manually operable acknowledging device on the vehicle conveniently accessible to the engineer and operable to maintain said apparatus inactive notwithstanding operation of said control means, said acknowledging device being efiective for a limited time only and only if operated prior to actuation of said apparatus, and signaling means on the vehicle responding to the operation of said control means when said acknowledging device is operated, whereby the engineer is informed that the system is operating properly and would have applied the brakes if he had not operated the acknowledging device.

27 Automatic train control apparatus on a vehicle adapted when set into operation to continue in operation until restored, and manually operable means having a limited time of cfiective operation for preventing operation of said apparatus, and means accessible only from the ground for restoring said apparatus, said restoring means if maintained in its restoring condition acting to apply the brakes of the vehicle.

28. In an automatic train control system, the combination with a track device comprising an inert magnetic body and a coil thereon, means controlled in accordance with the presence and absence of trains aheadefor including said coil in a closed circuit without a trackway source of ener therein when there are no trains ahead and or opening said circuit when there is a train ahead, receiving means on the vehicle including an armature shifted upon passing said track device with its control circuit open, a normally inactive brake applying device on the vehicle set into operation by the shifting of said armature and thereby causing an automatic operation of the air brakes of the vehicle, manually o erable acknowledging means on the vehic e conveniently accessible to the engineer and operable to maintain said brake applying device inactive in spite of movement of said armature, said acknowledging means when operated also simultaneously restoring said armature'to normal, said acknowledging means being eflective for a limited time only after each operation and also only it actuated prior to the operation of said brake applying device, and other means on the vehicle for restoring said armature and device to normal after the vehicle has been brought to a stop.

29. Car equipment for automatic train control systems of the type in which controlling impulses are communicated by the exchange of magi'ietic flux between the trackway and the vehicle, comprising a receiving coil, an an lion responsive to voltage changes in said coil, a stick relay governed by the audion, brake control means actuated by the relay, and manually operable means having a limited time of efiective operation for maintaining the brake control means inactive regardless of its control by the relay.

30. In an automatic train control system, the combination with brake control apparatus on a vehicle, control means on the vehicle automatically influenced from the trackway for initiating operation of said apparatus,

manually operable means on the vehicle adapted to maintain said apparatus inactive independently of the control thereof by said control means provided it is operated prior to the initiation of the operation of said apparatus, and signaling means operated by said control means when it is influenced from the trackway.

31. In an automatic train control system. a brake applying appliance on a vehicle, a control device onthe vehicle governing said anpliance,means-partlyonthevehicle and partly on the track automatically controlled in accordance withtraflic conditions and cooperating inductively through an air-gap for initiating operation of said control device under danger traflic conditions but not under clear traffic conditions, said control device remaining in its operated conditions until restored, a manually operable acknowledging device on the vehicle for maintaining said brake applying device inactive notwithstanding operation of said control device and also for restoring said control device to normal, said acknowledging device being effective for a limited time only after each manual actuation and also effective only it actuated prior to operation of the brake appliance, and a signal on on the vehicle responding to the operation fill of the control device when said acknowledging device is actuated, whereby the signal indicates proper performance of the system and shows that the brakes would have been applied it the acknowledging device had not been actuated.

An automatic train control system comprising train control apparatus which if initiated will control the safe movement of the train regardless of efforts made by the engineer to prevent such control, influence transmitting means partly on the vehicle and partly on the track for initiating said apparatus dependent on traflic conditions ahead, means operable by the engineer and effective for a limited time only for permitting the engineer to avoid operation of the train control apparatus by taking appropriate action prior to the reception of an influence, and means accessible only from the ground for restoring said train control apparatus to normal, said restoring means acting to apply the brakes of the vehicle it maintained in its restoring condition.

33. An automatic train control system comprising train control apparatus which it initiated will control the safe movement of the train regardless of efforts made by the engineer to prevent such control, influcnce transmitting means partly on the vehicle and partly on the track for initiating said apparatus dependent on traffic conditions ahead, means operable by the engineer and effective for a limited time only for permitting the engineer to avoid operation of the train control apparatus by taking appropriateaction prior to the reception of an influence, and means accessible only from the ground for resto ing said train control apparatus to normal, said restoring means permitting said train control apparatus to be inactive only if said restoring means is in its non-restoring condition.

84:. An automatic train control system comprising, automatic brake control apparatns acting on the usual air brake system of a. railway vehicle and adapted to apply the brakes upon the reception of a danger influence from the trackway dependent on traflic conditions ahead, manually operable means efi'ective only for a predetermined time and only it actuated prior to the reception of such danger influence for preventing an application of the brakes by said apparatus, and signaling means actuated by said danger influence while said manual operable means has been actuated to indicate communication of the danger influence.

An automatic train control system comprising, automatic brake control apparatus arranged to act upon the usual air brake system and making an unpreventable brake application upon the reception of a danger influence from the trackway dependent on traflic conditions ahead, manually opcrable means effective only for a predetermined pcriod of time and only if actuated prior to the reception of such danger in fluence for preventing an automatic applicaof the brakes by said apparatus, and means accessible only from the ground acting when operated to restore part of said apparatus to its normal condition and to restore all of said apparatus when returned to its normal condition.

36. Car equipment for automatic train control systems comprising, brake control 11;. pa 'atus acting on the usual air brake equip ment. a relay for governing said apparatus adapted to be actuated by a control influence from the trackway, a manually operable de vice ctl'ective only if actuated prior to the reception of such control influence to prevent the actuation of said apparatus said device being eli'cctive only for a predetermined period of time after its initiation to prevent such actuation, and means accessible only from the ground to restore said relay to normal, said restoring means so long as held in its restoring condition acting to maintain said brake controlled apparatus active. whereby said restoring means must be re turned to its normal conditions to permit the brakes to be released.

37. An automatic train control .5 stem comprising, a normally energized electrically COIltlOlltlblC brake control device acting upon the usual air brake system, a relayinfluenced from the trackway dependent on traflic conditions ahead and normally maintaining said device inactive, an auxiliary circuit for said device including contacts closed only it said device is energized, signaling means in said auxiliary circuit, and manually operable means for closing said auxiliary circuit. whereby operation of said brake control device may be prevented by antecedent manipulation of said manually operable means, while the signaling means signifies that the system operating properly and would have initiated operation of the brake control means except for manual interference.

In a train control system, means partly on the vehicle and partly on the track for producing a control influence on the vehicle under danger tratlic conditions, apparatus on the vehicle including braking means responding to said influences and operable to compel the vehicle to come to a stop in spite of any action on the part of the engineer, said braking means when operated remaining active until specially restored, manually operable means on the yehicle having a limited time of effective action for preventing response of said braking means to such influences only if said manually operable means is actuated prior to the reception of such influence, and a manually operable device on the vehicle accessible only from the ground and acting when operated to restore said apparatus but not said braking means. permitting said manually operable device when restored to its normal condition after actuation thereof to automatically restore.

said breaking means.

39. Car equipment toms comprising, control apparatus, control means adapted; to be automatically influenced from the trackway for initiating the operation of said apparatus, said control means if onceinfluenced continuing in that state until restored, manually operable means having a limitedtime of effective action and also effective only if actuated prior to the initiation of the operation of said apparatus for maintaining the apparatus inactive independently of its control by the control means and for restoring said control means to normal.

40. Car equipment for train control systems comprising, the combination with brake control apparatus, control means adapted to be automatically influenced from the trackway for initiating the operation of said apparatus, said apparatus and control means if rendered active continuing in that state until restored, manually operable means eflective only if actuated prior to the initiation of the operation of said apparatus for preventing such operation independently of said control means and for restoring said control means, and other manually operable means accessible only from the ground for restoring said control means after operation of said apparatus.

41. Our equipment for train control systems comprising, the combination with brake control apparatus, control meansadapted to be automatically influenced from the trackway for initiating the operation of said apparatus, said control means if once influenced continuing in that state and maintaining said apparatus active until restored, manually operable means eflective only if actuated prior to the influencing of said control means from the trackway for maintaining said apparatus inactive and for restoring the control means, automatic means for causing a brake application if the manually operable means is kept in its actuated condition longer than a limited time. and other manually operable means accessible only from the ground for restoring the control means after said apparatus has operated.

42. In a train control system, the combination with a safety device on a vehicle adapted to be automatically actuated from the trackway at each caution signal, a normally closed circuit maintaining said safety device inactive, a normally open circuit which when closed will maintain said safety device inactive independently of said normally closed circuit, means for breaking said circuit at one point upon operation of said d evice,manually operable means for closing said for train control systhe combination with brake circuit at another point, and means accessible only from the ground for restoring said device after actuation thereof, said restoring means having normally closed contacts included in the normally closed circuit and opened whenthe restoring means is actuated.

43. In a train control system, means partly on the vehicle and partly on the track for producing a control influence on the vehicle at eachcaution signal, a device governed by said control influence and continuing in operation until restored,- manually operable means effective if actuated prior to the operation of said device for preventing that operation, and means accessible only from the ground for restoring said device after operation thereof, said restoring means when shifted to the restoring condition causing an automatic brake application.

44. The combination with a control stick relay on a vehicle, brake control apparatus governed by said relay and a manually operable device which it' shifted prior to the operation of said apparatus prevents such opera.- tion and restores the controlling relay, and other manually operable means for restoring said relay after operation of said apparatus, said other manually operable means while in the operated restoring condition maintaining said apparatus active, whereby said restoring means can not be kept in its restor in condition without causing operation of said apparatus.

45. Car equipment for train control systems comprising, a control device automatically influenced from the trackway, brake setting apparatus governed by said device, said control device and apparatus when once setinto operation continuing in operation until restored, and manually operable means for restoring said control device alone and acting while in its restoring condition to permit operation of said apparatus.

46. Car equipment for train, control systerns comprising, a stick relay, a brake setting device, an energizing circuit for said dcvice broken upon deenergization of the stick relay, and a manually operable circuit controller for picking up said stick relay and at the same/time opening a normally closed break in said energizing circuit. whereby said circuit controller after operation thereof to restore the stick relay must be returned to its normal condition to permit energization of the brake setting device.

47. In a train control system, the combination with brake control apparatus influenced inductively from the trackway through an intervening air gap under dangerous traflic conditions, means readily operable by the engineer While at his post for preventing operation'of said apparatus in response to such influence only provided said means is operated by the engineer prior to the reception of said influence, automatic means for applymg the brakes it said means operable by the engineer is maintained in its operated condition longer than a predetermined time, and a reset device accessible only from the ground for restoring said apparatus.

A train control system, characterized by means readily operable by the engineer without leaving his post for permitting him to avoid an automatic brake application in response to an influence from the trackway only if he takes action prior to the reception of "ich influence, together with signaling means effective it such action has been taken by the engineer to inform him that the system is working properly.

l9. A train control system of the general ype described characterized by the provision of means by which the engineer by suitable manual manipulation if made within a limited time prior to the reception of an influence from the trackway may prevent an automatic application of the brakes as a consequence of the reception of such influence, together with means ineffective to eliminate such brake application for compelling the train to be brought to a stop in order to release the brakes after such automatic application, and signaling means indicating the reception of such influence notwithstanding the manual manipulation of the engineer.

50. An automatic train control system comprising, brake control apparatus, which will effect an unpreventable brake application it initiated, means operated in response to the reception of a control influence dependent on trafiic conditions ahead for initiating said apparatus, means manually operable by the engineer and effective for a limited time only for permitting the engineer to avoid operation of the brake control apparatus only by taking appropriate action prior to the rcception of an influence, signalling means operated upon the reception of an influence if said manually operable means is operated, and means accessible only from the ground for restoring said brake control apparatus to normal, said restoring means permitting said brake control apparatus to be inactive only it said restoring means is in its non-restoring condition.

51. An acknowledging device protected against misuse by holding it in its active condition permanently, comprising a shaft, spring means for driving said shaft, clockwise mechanism for retarding rotation of said shaft y said spring means, means for winding said spring means each time the device is put in its active acknowledging condition, and means for opening a circuit if said device is kept in its active acknowledging condition for more than a predetermined i11- lerval of time.

52. An acknowledging device for use in combination with brake control apparatus for train control systems for preventing a brake application fora limited time only comprising, normally open contacts and normally closed contacts, a manually movable element operable when moved to one extreme position to close the open contacts, timing means having a retarded movement for opening the closed contacts after a time interval, and means in which energy is automatically released and stored as said element is moved toward and away from said extreme position respectively for operating said timing means.

53. In combination, a spindle biased to one position and arranged when moved out of such position to return thereto with a uniform slow angular velocity a first contact arranged to be closed when said spindle is moved away from such one position, a handle having a given position and capable of manual movement away from such position to move said spindle away from said one position, and a second contact closed only when said handle occupies said given position.

5- Railway trafiic controlling apparatus comprising automatic mechanism carried on a train and operating under unsafe traffic conditions to apply the brakes, a spindle biased to one position and arranged when moved out of such position to return thereto with a uniform slow angular velocity, a first contact arranged to be closed when said spindle is moved away from such one position, a handle having a given position and capable of manual movement away from such position to move said spindle away from said one position, a second contact closed only when said handle occupies said given position, and means controlled by said first and said second contacts for preventing an automatic brake application.

55. Railway traffic controlling apparatus comprising automatic mechanism carried on a train and operating under unsafe trafiic conditions to apply the brakes, a. spindle biased to one position and arranged when moved out of. such position to return thereto with a uniform slow angular velocity, a first contact arranged to be closed when said spindle is moved away from such one position. a handle having a given position and capable of manual movement away from such position to move said spindle away from said one position. a second contact closed only when said handle occupies said given position, and means effective only when said two contacts are closed to prevent. an automatic brake application.

In testimony whereof I afiix my signature.

CHARLES S. BUSHNELL.

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