US1615203A - Train control - Google Patents

Description

27. Jan 18 o, H. DIcKE TRAIN CONTROL Filed Sept. 20, 1923 game. Md

- ATTORNEY Patented J an. 18, 1927.

UNITED STATES 1,615,2t3 PATENT OFFICE.

OSCAR H. DICKE, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIG- NAL COMPANY, OF ROCHESTER, NEW YORK.

TRAIN CONTROL.

Application filed September 20, 1923.

This invention relates to automatic train control systems for railways.

Among the various requirements of a suitable automatic train control system for railroads, it is consideret to be expedient to provideautomatic means for stopping the train absolutely at times and under certain conditions, such as upon the approach to drawbridges, crossings, and in general at those places Where a stop-and-stay signal is employed according to accepted signal practice. This absolute stop control is ditl'erent from the ordinary so-called automatic stop, and it is contemplated that the automatic means providing for such absolute stop will be used in conjunction with suitable means for providing the appropriate control of the train in permissive or block signal territory, preferably by enforcing restrictive speed limits. While the absolute stop in question may be obtained by the use of a derail, there are many disadvantages and objections to derails, so that it is desirable to have a sepa rate and absolute stop control of the brakes of the train. I

In one particular type of train control system, to which the present invention more particularly relates, the means communicating control influences from the trackway to the moving train is of a continuous inductive type, in which, among other things, the train must continuously find flowing in two distinct traclrway circuits, including the track rails an alternating signaling current. In this type of system, three distinctive controls are obtainable, two by changing the relative phase relation of the signaling currents in the traclrway circuits, and the other by cutting oil one of said signaling currents. Generally speaking, for reasons familiar to those skilled in the art and to some extent pointed out hereinafter, it is found expediout to utilize all three of these controls for governing the train movement in permissive .or block signal territory, leaving nothing available to give an absolute stop. The present invention relates more particularly to the provision of a fourth or additional control in such a three-control continuous inductive system, this additional control for absolute stop being obtained without additional complication and in a safe and effective manner in conformity with the continuous control principle of failure on the side of safety.

Serial No. 663,820.

neer, so as to obtain the combined protection afforded by the automatic train control system and that provided by the prudent engineer, it has ordinarily been considered desirable to penalize the engineer each time the arbitrary speed limits are exceeded and a brake application occurs; but, as above in dicated, on account of the inaccuracies of the speed limits with respect to actual braking conditions, strict adherence to this method of maintaining vigilance tends to introduce delays.

VYhile retaining the same theory of stimulating vigilance of the engineer by penalizing him for neglect of duty, the present invention contemplates the provision of means whereby the engineer, by making a timely application of the brakes, may exceed the speed limits arbitrarily established without penalty. More specifically, it is proposed to provide a unitary device which is responsive to the rate of deceleration of the train as well as to its actual speed of movement, so that said device will indicate or reflect what may be termed the apparent speed which represents the combined effects of the actual speed and the rate of retardation. IVith the aid of such a combined speed and decelera-- tion responsive device, the system is organized, as more fully explained hereinafter, so that the artificial speed limits may be exceed ed from time to time, without an automatic brake application and without penalty, provided the engineer has applied the brakes manually and the train is being safely controlled, this condition of safe retardation being determined by this device.

Other objects, purposes, and characteristic features of the invention will appear as the description thereof progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in which Figure 1 illustrates in a conventional and diagrammatic manner the trackway and carcarried apparatus of a train control system. embodying the present invention; and

Fig. 2 graphically illustrates the permissive speed, the actual speed the vehicle may attain providing the train is being decelerated, and the apparent speed the vehicle attains in running through a caution block when the brakesare active in signal territory, and also illustrates similar graphs of a block at the approach to an absolute stop point under stop conditions of this block.

Traci-sway appcuutus.Iii describing the particular embodiment of the invention illustrated in Fig. 1, the trackway circuits and apparatus will be first described, after which the description of the car-carried apparatus and the operation of the system will be taken up. Although the train control system embodying the present invention may be applied to any type of block signaling system, and to any type of interlocking,

using either alternating or direct current track circuits, for convenience the application of the invention to a block signal systern employing alternating current track circuits only has been illustrated, together with a typical block at the approach to an absolute signal in interlocking territory or the like.

The track rails 1 have been shown divided by insulating joints 2 into blocks in the usual manner. The block I, and also the adjacent end of the block H partially shown, are representative or typical of the trackway equipment and arrangement employed in block signal or permissive control territory; whereas the block J is typical of the arrangement employed at the approach to an absolute stop-and-stay signal, which for simplicity may be assumed to be the absolute home signal commonly used in interlocking territory. Since the equipment of the various blocks is substantially the same, the diiierences being pointed out hereinafter, the blocks I and J and the adjacent ends of the blocks H and K only have been shown, and for convenience like parts have been assigned like reference numbers with distinctive exponents. Each of the blocks is divided by insulating joints 3 into two sections, conveniently referred to as the first or rear section, and the second or advance section, respectively. The present train control system is preferably although not necessarily used with the usual fixed wayside signals, which may be either of the position light, color light or semaphore signal type and may be controlled in any approved fashion; and for convenience semaphore signals Z have been illustrated without showing their well-known circuits and control apparatus. The energy for operating the signals, relays, etc. is derived from a suitable alternating current transmission line T.

The first or rear sect-ion of each block is provided with the usual track relay 4 normally energized by track circuit current applied to the exit end of this section. The circuit of the block I for supplying this trackway current to its rear section under clear tral'lic conditions ahead n'iay be traced as tollows1-l3eginning at the secondary winding of the transt'orn'ier t5 energized from the transmission line '1, wire 7, front contact 8 oi? the track relay 1 wires 9 and 10, front contact 11 of the track relay 5, wire 12, track rail 1, wire 13, winding of the track relay l, wire l i, the other track rail 1, wires 15 and 1(5, tront contact 17 01 the track relay i the usual limiting impedance 18, wire 19 back to the secondary winding of the transformer (5.

Under caution trailic conditions, the rela tive direction of flow of current in this rear section of the block I is reversed because the track relay 4. is then deenergized, this current flowing through the same circuit as just traced except that back contacts 20 and 21 are used instead of contacts 8 and 17 At the midpoint of the second or advance section of each block is provided a track relay 5, which is energized under clear and caution traltic conditions by energy supplied at the exit end' and entrance end, respectively, of this second section. This second section or the block I is under normal clear traflic conditions energized by current supplied to the exit end thereof by a circuit which may be traced tollows:-Beginning at the secondary winding of the trans tormerb, wires 7 and 22, front contact 23 of the track relay 1 wire 2st, track rail 1, wire 25, winding of the track relay 5, wire 26, the other track rail 1, wire 27, front contact 28 of the track relay et wire 29, the usual limiting impedance 30, wires 31 and 19 back to the secondary winding of the transformer 6.

Under caution traiiic conditions of the block I, this second section of the block is provided with track circuit current from the entrance end through the following circuit:--Beginning at the secondary winding of the transformer 6, wires 7 and 22, back contact 32 of the track relay 9, wire 33-, the rail 1, wire 25, winding of the track relay 5, wire 26, the other rail 1, wire 34:, back contact 35', wire 29, limiting imped ance 30, wires31 and 19 back to the transformer 6.

By looking at block I of the drawings, it will be noted that track or loop circuit current is supplied to the two sections of the trackway in a manner so as to flow in a normal direction under clear traiiic conditions iii) led

of the block J, and that the first section of the block I has its current reversed if the block J is occupied, and that the second section of the block I has current supplied thereto by being fed from the entrance end of this section when the next block in advance (block J) is Occupied.

Both of the sections of the block I are provided with means for supplying simplex circuit current, that is, current flowing in the two rails in multiple; and for reasons heretofore mentioned, this simplex circuit current is continuously supplied to both sections of this block regardless of trafiic conditions ahead, by a' transformer 69 having its secondary winding connected to the mid points of balancing resistances 36 and 3'4", respectively, and a transformer 7 9 having its secondary winding connected to the midpoints of balancing resistances 38 and 39, respectively, so that current is supplied flowing through the two rails in multiple in each of these sections of the block I, this current dividing substantially equally between the two rails.

On account of the inductance of the track rails and the track circuit impedance, the track or loop circuit current lags considerably behind the voltage of the source of alternating current supplied over the transmission line T; whereas the current supplied to the simplex circuits is a resistive or power current, and is substantially in phase with the voltage producing it. In other words, the track or loop circuit current lags substantially electrical degrees behind the simpler; circuit current, this being desirable for reasons more clearly described hereinafter. These track circuit currents may be brought into quadrature by any other means, for instance, a polyphase current may be transmitted along the right of way, if desired, or any other suitable means may be employed to bring these currents into the proper phase relation.

The block J, which is assumed to be a block in the rear of a home signal in interlocking territory, is in many respects similar to the block I in block signal territory. The main difference between the block I and the block J is that the various contacts for controlling the loop circuit current to the block J are controlled by a line relay 40 instead of the track relay 4 and that the in sulating joints 2 of the blocks are located a considerable distance beyond the signals Z this section between the signal and the insulating joint at the end of the block being provided with a controllable simplex circuit comprising balancing resistances 41 and 42, which may be supplied with energy at their midpoints by two distinctive circuits which may be traced as follows :Beginning at the secondary winding of the transformer 43. wires 44 and 45, front contact 46 of the line relay 40, wires 47 and 48 to the midpoint of balancing resistance 42, thence over the track rails to the midpoint of balancing resistance 41, wires 49, 50 and 51 back to the secondary winding of the transforn'ier 43; and a circuit beginning at the secondary winding of the transformer 43, wires 44 and 52, contact on the usual interlocking lever 53 in the tower 54, which lever is interlocked with levers of conflicting routes so that it can only be operated when it is proper to do so, wires 55 and 56, the call-on push button 57 also located in the signal tower 54 conventionally shown by a dotted rectangle, wires 58 and 48, balancing resistance 42, the two track rails in multiple, balancing resistance 41, wires 49, 50 and 51 back to the secondary winding of the transformer 43.

The line relay 40 is normally energized by the following circuit, which is closed 43, wires 51 and 60, front contact 61 of the track relay 4 wire 62, winding of the line relay 40, wires 63 and 55, contact of the usual interlocking lever located in the tower 54, wires 52 and 44 back to the secondary winding of the transformer 43.

On the sanie signal pole with the absolute stop-and-stay signal 5*? is provided a call on signal, which is intended to be used in accordance with recognized practice to callon the engineer or to advise him that he may proceed regardless of the fact that the stop-and-stay signal is at stop, as, for example, when it is desired to allow the second section of a train to follow closely behind the firstsection into such interlocking territory. This call-on signal is normally in the inclined non-indicating position as shown, and is placed in a vertical position when the following circuit is energized Beginning at the secondary winding of the transformer 43, wires 44 and 52, contact of the interlocking lever in the tower, wires 55 and 56, call-on push button contact 64, wire 65, control mechanism of the call-on signal 59, wires 66, 50 and 51 back to the secondary winding of the transformer 43.

By referring to the block J, it will be noted that the loop circuit. current for this block may be controlled automatically by the track relay 4 in the same manner as the current is controlled. in the block I, and that the block J may be put in its caution traffic condition by moving the lever 53 in the tower 54 into its dotted position. Also, it will be noted that if the block J is in its caution condition, either because the track relay 4 is deenergized or because the lever 53 is in its dotted position, the simplex circuit including the balancing resistances 41 and 42 is deenergized, and that an absolute stop is inflicted if a train passes the signal Z because of the absence of this simplex current, by reason of suitable car-carried apparatus to be described hereinafter. Also, it will be noted that if the block K is occupied by another train and the tower man wishes a train moving in the block J to pass into the block K, he may place the lever 53 in the clear position, as shown in the drawing, which will avail him nothing for the reason that the simplex circuit beyond the signal Z is still deenergized, because the front contact 46 of the line relay is in its lower position; and in order to permit the train to proceed, he must push the push button 67 whereby the arm of the call-on signal assumes its clear position and the simplex circuit is energized so that the train may proceed regardless of the condition of the track relay 4 From the foregoing it can be readily seen that, in block signal territory, represented by the block I, each block is divided by insulated joints 8 into two sections, the track rails of both of these sections being continuously and at all times irrespective of traffic conditions supplied with simplex current flowing in the same direction in the track rails at any given instant. The loop or track circuit current for the first or rear sec tion of each block is controlled, first as to continuity by the relay 5 of the second or advance section of the same block, and sec-- ond as to polarity or relative phase relation by the track relay of the block next in advance. The loop or track circuit current for the second or advance section of each block is normally and under clear trafiic conditions connected across the track rails at the exit end of that section, which is also the exit end of the block itself, and is shifted to a connection across the entrance end of this section under caution traffic conditions, that is, when the next block in advance is occupied.

In interlocking territory, or at points where an absolute stop control. is desired, the block, represented by the block J, in addition to the two sections arranged and controlled the same as in block signal territory, is provided with a short section as regards simplex current, although no insulated joints are employed, and the supply of simplex current to this short section at the end of the block and just beyond the home signal, is separately controlled so as to provide an absolute stop when required. In other words, the block for a home signal or other absolute control point has in effect three sections or portions, two of which are energized and controlled in the same way as in block signal territory, and the other of which is separately and ordinarily manually controlled to give an absolute stop whenever required.

It should be understood that the arrangement of the call-on signal and its particular manner of control illustrated is of course optional and susceptible n'iodiiication or adaptation in conformity with established interlocking practice; and it should also be understood that the traclnvay equipment and arrangement of circuits shown is diagrannnatic and illustrative, and is not in tended to include the various refinements, additions, or adaptations, that would be adopted in practice in applying the invention to the varying conditions encountered on railroads.

(l'naucmvw rc (anyHowitzer-For convenience a railway vehicle has been convcntionally illustrated by show the first and a subsequent axle T0 and 71, respectively, of an eu glue and tender unit, or car of a multiple unit GlQttl'lC train, depending upon the t of train to which the train control s embodying the present system is a Carried on the vehicle directly in fro the first axle Tl) are two suitable influence detecting or receiving elements LE for detect ing the flow of alternating current flowing in the loop circuit on the tracliway. These loop circuit receiving elements LE e2 ch coinprise a core 72 of suitable magnetic material, preferably laminated, insulated between lam inn and supported a suitable distance above the track rails so as to afford the proper clearance. This core 72 of each of thes elements has depending legs terminating in pole pieces 73, and is provided with a coil 74. The coils 74 of the two receiving ele ments LE are connected in series in a n ner so that curr nt flowing in one direction in one rail through the axle of the vehicle and back in the other direction in the other rail will induce electro-inotive-forces in the coils 74: which are cumulative.

Similarly, a simplex intluence receiving element SE for detecting simplex current flowing through the two rails in multiple is carried on the vehicle in the 1' air of the axle 71. This element SE con'iprises a similar but longer core 75 having depending legs terminating in pole pieces 76, and provi-iled with a winding 77 in which electro-motiveforces are induced due to current. flowing in the same direction in the two rails in multiple.

The loop circuit current influence detecting element LE is connected to a loop circuit amplifying device, which has been conveir tionally illustrated by a square AL. This amplifying device AL has its output wires connected to the winding 80 of a two-element relay CR through the front contact 81 of a reset and penalizing switch, more fully described hereinafter, through circuit which may be readily traced in the drawings. This amplifying device is designed so that currents flowing in the loop circuit ahead of the train are reproduced, amplified, and applied without change in phase to the winding 80 of the control relay OR.

The winding 77 of the simplex influence receiving element is connected to an amplifying device conventionally shown by a square and designated AS. The output circuit of this simplex anniilifying device AS is connected to the other winding 82 of the control relay CR, and also to the winding of the stop relay S in a manner as shown in the drawings. These amplifying devices AL and AS include the usual vacuum tube or thermionic amplifiers, coupling units, and

the necessary tuning apparatus and sources of energy, all as well understood by those skilled in the art of thermionic radio conimunication.

In order to inform the engineer of the positions of the control relay GR, and in turn the conditions of trallic ahead of the train, suitable signals are preferably provided at convenient. place in the cab for giving such information. For convenience, such signals have been conventionally shown by four lamps colored green, yellow, red and orange re pectively, and designated G, Y, R and 0, respectively. These lamps are at times energized by being connected across the. terminals B and C respectively of a suitable vehicle carried source of energy by circuits readily traced in the drawings. These circuits n'iaintain the green lamp G energized when traffic conditions ahead are clear and the relay GR is in its normal position; mainta n the yellow lamp Y energized when traflie conditions are caution and the relay GR is in its reverse position maintain the red lamp R energized when the relay Clt deenergized corresponding to danger trafiic conditions ahead; and maintain both the red and the orange lamp energized when an absolute stop is being enforced and the stop relay S assumes its deenergized position.

in order to manifest on the train that it is being slowed down properly in a caution block in response to a manual application of the brakes, as well as the running speed of the vehicle, a suitable combined centrifugal speed responsive device and decelerating device has been provided, which may for convenience be referred to as an apparent speed indicator. This ai iparcnt speed indicator All; costs of the reason? elements of at ii'ilif ii e device and means x *"on of this device in accordance with deceleration of the tram.

More specifically, this apparent speed indicator AG comprises a shaft 85 mechanically connected and driven by one of the axles of the railway vehicle by suitable means to rotate it in the same direction (in the particular arrangement shown, this direction being anti-clockwise as indicated by the arrow), regardless of the direction of movement of the train, that is, regardless of whether it is moving pilot or tender first. From the shaft 85 projects a radially extending pin 86 engaging a helical slot 87 in a sleeve 88 surrounding and loose on the shaft 85. This sleeve 88 has ears 88 extending therefrom to which are pivotally secured links 90 having their free ends connected to centrifugal weights 91. The sleeve 88 is held in its normal position shown by a torsion spring 92 contained on the shaft 85, having one end fastened to the shaft by a pin 93, and having its other end secured to the sleeve 88 by a screw 9st. 011 the shaft 85 above the sleeve 88 is supported another sleeve 95 having similar cars 95 to which are pivotally secured links 97, having their free ends pivotally connected to the centrifugal weights 91; On the shaft 85, between the sleeves 88 and 95, is a compression coil spring 98 which urges these sleeves apart, so that the weights 91 closely approach each other while the shaft 85 is at rest. To the sleeve 95 is fastened but insulated therefrom a grooved collar 99, in the groove of which extends the bifurcated endof an indicating arm 100 pivotally supported by a pin 101.

Upon consideration of this structure of the apparent speed indicating device AG, it will be noted that, if the shaft 85 is rotating at a constant speed, the speed indicating arm 100 will move about its pivot to a position corresponding to the speed of the shaft 85 by the action of centrifugal force upon the Weights 91 in the usual manner, and also that if the shaft 85 is rotating at a constant speed or is accelerating the pin 86 will engage the end of the slot 87 (as shown) sothat the sleeve 88 maintains the same relative position with respect to the shaft 85 as it does when at rest and the speed of the train is accurately indicated by the speed arm 100.

However, if the shaft after having been 1 running at a certain. speed is retarded or de cclerated, the inertia of the weights 91 causes these weights and the sleeves 88 and 95 to be positioned a certain angle ahead or slightly in advance of the shaft 85. lVhile l the sleeve 88 and the weights 91 are positively driven at the same rate as the shaft 85 so long as this-shaft is accelerating or rotating at a constant speed, whenever this shaft decelerates or slows down, the slot 87 permits the sleeve. 88 and the connected parts to move relatively with respect to the shaft, this relative movement being opposed by the spring 92. On account of the shaoe and angularity of the slot 87, this relative movement of the sleeve 88 with respect to the shaft 85 forces the whole centrifugal device endwise on the shaft 85, changing the position of the arm 100, the same as if the speed of rotation of the shaft 85 were lower and designated AV has been shown.

and the centrifugal weights 91 were not so far out. It will be evident that, by properly proportioning the spring 92 and shape of the cam slot 87, with due regard to the vari-.

In the particular embodiment of the invention illustrated, the apparatus is preferably designed so that the deceleration that ordinarily takes place when a train is being braked by a. full service application will cause the speed arm 100to indicate an apparent speed, which is substantially miles per hour less than the actual running speed of the vehicle, for reasons more clearly described hereinafter.

The speed indicating arm 100 is adapted to move over contacts 102, 103 and 104, respectively. which are of such length that they are in contact with this speed arm 100 if the train is moving at therate of less than 20, or miles per hour, respectively. These specific speed limits are chosen for the purpose of illustration only, and may be departed from in practice, if desired. These contacts 104, 103 and 102 are connected to the terminal B of a source of energy when the stop relay S is energized and the control relay GR is energized in the normal position, in the reverse position or is deenergizcd, respectively.

' In order to automatically apply the brakes 0f the usual air-brake system, a suitable ap plication valve diagrammatically illustrated This application valve is connected to the main reservoir 7MB. the brake pipe BP. atmosphere AT, to the usual enginecrs brake valve EV and to an equalizing reservoir and a reduction reservoir ER and RR, respectively. This application valve preferably designed to automatically vent the brake pipe to a predetermined extentwhen actuated, and to cut oil main reservoir pressure l roin the engineers brake valveso that the engineer may not prevent an automatic brake application by placing the usual engineefis brake valve into the release position to recharge the brake pipe. Since this application only forms an element in the present system, it has not. been specifically shown and describedz and for a specific disclosure thereof, attention is directed to the copending application Ser. No. 596.102. filed October21, 1922,,by Charles SyBushnell.

This application valve AV is constructed sothat if air is vented from the pipe 105, the valve is actuated and automatically applies the brakes in the manner above described.

This pipe 105 is connected 'to an electropneumatic valve EPV, which maintains this pipe closed when the device EPV is energized but connects it to atmosphere if it is deenergized. The device EPV may be constructed in any suitable manner so as to dicating arm 100, which, under predetermined traffic conditions, is connected to the terminal B of abattery through the contact 68 and one of the contact strips 102, 103 and 104, wire 107, winding 108 of. the device EPV, wires 109 and 110, front contact 106, wire 111 back to the other terminal C of said source of energy. It is thus noted. that the device EP'V is connected in a stick circuit which it' momentarily decnergized will prevent reenergization of the device, because its energizing circuit is broken by its own front contact.

Another element of the car equipment is the reset switch RS which has to be operated to permitthe brakes to be released a .d the trainto proceed after default by the en gineer and an automatic application of the brakes has occurred. This reset switch BS is shown diagrammatically a simple switch or push button having normally open contacts and norn'ially closed contacts n'iechanically connected and simultaneously operated. The normally open cont cts are for performing the resetting function, while the normally closed contacts are for protecting the reset switch against misuse.

As indicated by the dotted rectangle. this reset switch H in practice is preferably cnclosed in a suitable nrotectiug box or casing so mounted on the locomotive or other vehicle that it can be reached only by a pcrson. standing on the ground. in oth r words. the reset switch RF) is accessible only from the ground, and the train must he sto ed before the switch can be operated. lr ecssrcd, a. suitable recorder or counter may be used. with the switch to make a permanent record of the number of times it is operated or. the enclosing box may be locked and the hey held by the conductor, or the box may be sealed or some other e"pcdieut adopted to assure report each time said switch is operated, so as to give the ol'iicials information about the care and vigilance of the various. engineers. It should be understood that provision of such a reset switch, acres only from the ground, as the means alizing the engineer is merely illustra a suitable penalizing means, and 0th.

rangements for inflicting a penalty be lee employed so far as the fundamental functions and attributes of the system are concerned.

In an automatic train control s stem of the continuous inductive type provided wi h means ci'in tructed in accordance with this invention for producing an absolute stop, it a 'lailure of tracliuuiy one I should occur for any reason, or a simpler: circuit along the tracliway should be in errupted, the train would he brought to a stop and could not proceed. in order to allow the train to proceed at all under such conditions, a suitable emergency cutout novice has been provided, which con'iprises a *alve 112 con nected in the pipe 105 between the device EPV and the application valve AV, so that it the engineer closes this valve iii the ap plicat-ion valve w' l not be actuated regardless of the condition of the device lQlPV. in order to prevent the engineer from maliciously placing this valve in the cut-oil position so as to avoid the autou "'ic application of the brakes and the resultin .-alty, this cutout device is normally placed in its inetlective position and maintained in this position by a seal 113. It for any reason the engineer is unable to proceed at a point along the trackway where he should be oermitted to proceed, he may break this seal 113 for which he will be excused under such conditions. it, however, the seal is broken at a time when both the tracltway and car-earrie-c apparatus are in working order, th en gineer could be severely criticized and probaoly discharged for breaking the seal under these conditions.

)PERATION OF THE SYSTENE.

Speed control and bloc/c signal tcrritry. li hi e the train is running under cl a:- sig nals in a clear block, the loop circuit current tor the lirst or rear section ot the block is of noru'ial polarity, and that for the second or advance section is of normal polarity and is fed from the exit end ot the block. The simplex circuit current, as already pointed out, always present in both sections of the blocks in block signal territory. Consequently, both field windings 80 and 82 of tlie relay CR are energized by the amplified energy induced in the receiving elements LE and CE by this loop circuit: and siuralex circuitcurrent. ,1ilso,cncrgy is supplied to the stop relay S, maintaining its contact finger or armature in the upper position shown.

W ith the relay GR in the normal position shown, the green light G is illuminated, and the long or maximum speed contact strip included in the circuit tor the electropneumatic valve EPV. The train may travel at any speed less than the maximum speed for which the apparatus is desiaed, say miles per hour. If this maximum speed limit is exceeded at any time, the arm leaves contact with the strip 104 and breaks the energizing circuit for the electro-pneumatic valve EPV, which opens and applies the brakes automatically thron the agency of the application valve AV. As soon as the electro-pneumatic valve EPV is dcenergized, its front or stick contact 106 opens, so that irrespective of subsequent reduction in speed and engagement of the arm lOOwith the strip 104, said electro-pneumatic valve can not be re-energized. In other words, whenever the maximum speed is exceeded, the brakes are applied and held applied until the electro-pneumatic valve is independently restored by the reset switch IS. To reset the electro-pneumatic valve EPV after automatic operation thereof, the train must be brought to a stop and the reset switch RS operated, closing its open contacts and opening its closed contacts. The closure or the open contacts 121 of the reset sv-ritch RS establishes, together with wire it Q, a multiple or shunt connection to the tminal oi the battery designated C in lieu of that through the contacts 106 of the electropneumatic valve, so that with the circuit of this valve closed at some one of the strips 102, 103 and 104, the valve is re-energized and after such energization is maintained energized by its normal circuits.

It will be noted that the normally closed contacts 81 of the reset switch RS are included in the circuit for the field coil 80 of the relay CR, so that with the reset switch operated, the lield coil 80 is deenergized regardless of the presence o1"- loop circuit current and the relay GR is deenergized, limiting the speed to the minimum speed. In other words, so long as the reset switch RS is held in its operated or resetting condition, the train can not proceed above the minimum speed. This assures that the reset switch RS will not be maliciously or carelessly left or fastened in the wrong position, but will be restored after each operation thereof.

For reasons explained more in detail hereinafter, the engineer may avoid the automatic brake application and the resulting penalty upon exceeding the n'iaximum speed limit by having the brakes applied. This helpful for the engineer in handling his train under untavorable conditions where it is diilicult to avoid ten'iporarily exceeding the maximum speed limit. Adequate safety is assured, however, by reason of the fact that the prevenilon of automatic braking and the suppression of the penalty is efi'ective only so long as the brakes are applied; and'so as safety s concerned, it is not material whether the train is being slowed down due to a manual aoplication of the a ics already in effect, or by an automatic brake application initiated by exceeding the artificial speed limit.

lit)

a limit.

Speed control in a caution blockhen the train enters a caution block, that is, a block next in the rear of a block in a dangerous condition dueto thepresence of another train or otherwise, it is necessary to assure regulation of the speed of the following train in such a fashion that it will be brought to a stop, or to a predetermined minimum speed, before reaching the end of the block. In other words, the beginning of the next block in advance is taken to be the point of danger, and the train in the caution block is controlled so as to stop, or be brought down toa safe lowspeed, before reaching the point of danger.

According to this invention, the desired control of the speed in a caution block is obtained by setting up in succession .an in termediate speed limit and a minimum speed lVhile other well-known expedients may be employed, the change from the maximum speed limit for clear tratlic conditions to the intermediate speed limit is made abruptly, and likewise that from the intermeblock H in the normal direction of traffic,

as indicated by the arrow, when the block J is occupied by another train. lVith the block J occupied by. another train, the track relay .41 assumes its deenergized position and reverses the relative polarity of the loop circuit current in the first or rear section of the block 1 and transfers the track .ct'eed of the second or advance section of the block I from the exit end to the entrance end thereof in the manner heretofore explained. As the vehicle moves into the block-I, the control relay CR assumes its reverse energized position because of the reversal of the loop circuit current, thereby illuminating the yellow lamp Y and supplying energy to the contact strip 103, instead of the contact strip 104i, of the apparent speed indicating device. Since the contact strip 10stis no longer connected to the terminal B of the source of energy but the contact strip 103 is so connected, if the speed of the train is abore, say 10 miles per hour so that the arm 100 is not in contact with the strip103, it is necessary for the engineer to take appropriate action so as to bring the indicating arm 100 into contact with the strip 103 in order to avoid an automatic brake application and the resulting penalty.

In Fig. 2 has been illustrated graphically how the engineer may accomplish this result, although his speed just before entering the block is the maximum speed permitted, namely, miles per hour. The curves illustrated in Fig. 2 show the actual, the permissive and the apparent speed when the train being brought to a low speed in a caution block as the result of a manual brake application, the solid line 110 indicating the actual speed of the vehicle, the dotted line 117 indicating the permissive speed, and the dot and dash line 118 indicating the apparent speed the train is traveling, as indicated by the arm 100 of the apparent speed indicating device.

In order to prevent an automatic brake application and the infliction of a penalty, the engineer must either travel at a speed of less than 10 miles per hour or he must apply the brakes so that an adequate brake application is effected before reaching the entrance to the block 1. As soon as the brakes become active and deceleration of the vehicle takes place, the decelerating device, forming part of the apparent speed indicating device AG, begins to function causing the sleeve 88 to make a partial rotation with respect to the shaft in the direction of the arrow to cause the indicating arm to indicate the actual speed minus a. component, depending on deceleration. The dot and dash curve 118 illustrates how the apparent speed drops down very abruptly as the brakes become active, thus bringing the indicating arm on the contact segment 108 before the block I is entered. If the engineer keeps the brakes applied, the apparent speed will decrease at substantially the same rate as the actual speed, indicated by the curve 116 in Fig. 2, decreases with the brakes applied. The engineer is obliged to keep the brakes applied until the actual speed of the train is below the permissivespeed limit, that is, until the speed of the train, assumed to be about 60 miles per hour at the start, has been reduced below the 10 mile per hour permissive speed limit indicated by the dotted line 117. If the engineer should release the brakes, the deceleration of the shaft 85 at once ceases and the spring 92 acts to bring the sleeve 88 around to its normalposition, thereby raising'the upper sleeve and shifting the arm 100 to the position co responding to the actual running speed of the train, with the result that, if this actual speed is greater than the permissive speed limit, the arm moves out of contact with the strip 103 and the clectro-pneumatic valve EPV is deenergized, automatically applying the brakes and requiring a reset from the ground as a penalty.

1n the foregoing explanation, it was assumed that the train entered the caution block at-nearly the maximum permissible speed, requiring theengineer to make a full service application to avoid an automatic brake application and a resulting penalty.

It may happen, however, that the train enters the caution block in question at a speed somewhat lower than the maximum speed but still higher than the intermediate permissive speed limit put into effect upon reversal of the relay CR. Under these conditions, while an application of the brakes to some degree is necessary for safety, on account of the lower speed it is not essential that a full service application should be made. This situation is taken care of according to this invention by reason of the fact that, the less the actual speed of the train is above the permissive speed limit, the less the intensity of the brake application and the amount of deceleration necessary to move the arm into contact with the strip 103. Accordingly, the engineer of a train entering a caution block at a moderate speed may, if he desires, avoid the automatic application and penalty by making a partial service application, suliicient to bring the speed down to the intermediate speed limit at the proper point. The engineer may, of course, make a full service application upon entering each caution block, regardless of how much the actual speed is above the intermediate speed limit; but as soon as the actual speed has been brought below the permissive speed limit, the engineer may release the brakes and proceed at a little less than this permissive speed limit.

It may be explained here that a full serv ice application has been mentioned in the foregoing explanation on the assumption that the block lengths or at least the points where the intermediate speed limit is put into force will, in the interests of track ca pacity, be based on stopping the train with a full service application. This, however, is obviously optional. It should also be. understood that the first or rear section of the block may be longer than necessary to bring the train from its maximum speed to the intermediate speed limit, with the result that the braking curve 116 and the permissive speed limit line 117 will cross at'some point in the rear of the insulated joints 3. This is particularly true in case of long blocks, although in this case special expedients not herein disclosed may be employed, if desired, to cause the intern'iediate speed limit to be i-llective at some distance in advance of the physical cntrai'ico to the block, rather than at the entrance thereto. In. short, the particular curves ilh'istrated and the foregoing discussion are predicated upon cer tain assumed conditions which need not be followed and which ordinarily are variable in the application of the system to practical operating conditions. ln order to avoid complication, however, these various refinements, exceptions, and adaptations to the simple and fundamental application of the invention will not be analyzed and discussed.

As the train reaches the insulating joints 3 of the block I, the car-carried equipment is wholly deprived of loop circuit current ahead of the train, because the loop circuit current of this advance section is fed to the rails from the entrance end thereof, and is shunted by the axles of the train so that it is unable to reach the influence receiving elements LE at the. front of the train. This causes the relay CR to assume its deenergized position, thereby cutting energy 05 of the contact segment 103 and applying it to the contact segment 102, thereby setting up a minimum speed limit for the train of, say, 20 miles per hour. As shown by the curves in Fig. 2, the apparent speed of the train in the block I at the entrance to the second section of this block is just a little less than 20 miles per hour while it is being decelerated, and therefore no automatic brake application will take place if the en gineer maintains the brakes applied. As soon as the actual speed of the train comes below the speed limit of 20 miles per hour, the engineer may release the brakes without penalty. Upon release of the brakes, the deceleration of the train ceases and the apparent speed device indicates the actual speed instead of the apparent speed, as shown by the abrupt rise in the dot and .dash curve 118 at the end of the block 1.

Release in a caution block-If, while the train in question is in the rear or first section of the block I, the train ahead leaves the block J, the track relay 4 picks up, and the normal polarity of loop circuit current is applied to the track rails of the block I, restoring the control relay CR to the normal position Corresponding to a clear block. Tris restoration or" the relay GR changes the cab signals from yellow to green and the speed limit from the intermediate to the maximum in an obvious manner. If the train in question should happen to be in the second or advance section of the block I at the time the block J clears up, the picking up of the track relay 4 which acts to shift the loop circuit feed from the rear or entrance of this section to the advance or exit end, changing the feed such that this loop circuit current may be detected by the receiving elements LE, whereby the control relay GR is restored to normal with the re sults above indicated.

ZlH/nimmn speed in an occupied bZ007c.- As previously explained, a train is compelled to reduce its speed to a minimum speed while traveling through a caution block, this minimum speed existing on account of absence of loop circuit current in the second or advance section of such caution block and the 'deenergized condition of the control relay CR. If a train, having been brought down to a minimum speed in this manner, continues on and enters the danger or occupied block, the same minimum speed limit is maintained in effect. This is due to the fact that a train in an occupied or danger block can not pick up any loop circuit current and the control relay CR remains deenergized, this being true whether the dangerous condition of the block is due to the presence of another train or a broken rail, or the like.

Considering the situation in detail, assume a train in the first or rear section of the block J and a Following train, after having had its speed reduced while traveling,

through the caution block I, enters into this rear section of the block J. The following. train will not-pick up any loop circuit current, because this current, if present, is all shunted out or diverted by the wheels and axles of the forward train. It a train is in the second or advance section 01 the block J and a following train enters into said block, no loop circuit current is supplied to the following train, because the relay 5 is deenergized and has opened the circuit by which loop circuit current is supplied. If the following train should continue and enter into the advance section of the block J directly behind said another train, still it would not receive any loop circuit current, because in one instance, it the loop circuit current were fed from ahead at the exit end of the block J (block K clear), the forward train would shunt out this current, and in the other instance (block K occupied), the feed of the loop circuit of the section in question would be from the rear and would not affect the receiving elements LE on the following train.

Thus, irrespective of the location of a tr in in a block, whether in the rear or in the advance section, a following train is restricted to a minimum speed throughout its travel and approach to the forward train.

Release from mini-1211mm speed limit in an occupied bZ0c-7a.Under certain circumstances, a train may enter an occupied or danger block which shortly after such entrance clears up, that is, the train ahead has advanced out 0t that block or the other condition constituting danger has been removed. Under these conditions, it is sate and desirable to remove the minimum speed restriction and substitute a higher speed limit, permitting the train to accelerate, yet keeping it under controland assuring that it shall be stopped or brought to a low speed by the time it reaches the end of that block, provided the next block inadvance continues to be occupied. In short, upon change of a danger or occupied block to a caution block. it is desirable to. remove the minimum sgeed limit and substitute the intermediate speed limit, if the-train is far enough back, or retain the minimum speed limit, the same as in a caution block.

All of this is taken care of in the present invention. First, assume that the following train is in the first or rear section at the time the train ahead in the same block advances or the dangerous condition is removed, and the block changes from a danger block to a caution block. In this case, the loop circuit current is re-applied and transmitted to the following train. The polarity o1? this loop circuit current will be reversed, the block next in advance is occupied, and the relay CR will pick up from its deenergized position to the reverse or cautionposition, e-tablishing the llltQliTlC- diate speed limit. This speed limit is safe and proper under these conditions, heausc the following train in question has not yet reached the insulated joints 3 and has brale inc distance for this intermediate speed limit available. If, however, the train i in the second or advance section at the time the block changes from dang-er to caution, the minimum speed limit is maintained, and properly so, because there may not be braking distance available to stop the train from any higher speed limit before reaching the end of the block. It will be evident that, if a danger block changes to a clear block, the minin'uim speed limit is removed and the maximum clear speed limit is substituted.

loam/11c .s'1op.-lhe block J is intend-ed to represent a typical instance of enforced speed reduction followed by an absolute stop to entorcc the proper recognition to the home and dis ant signals of an interlocki plant. In ad lition, the block J provided with the same control as in block signal ritory, so that trains traveling through thi block are at times under control as in block signal territory, that is, under the control oi? trains ahead, and at other times are under the manual control charactcrisli4 oi an interlocking system. The features o t speed control. in block s 'ial territory lwrcioi'orc discussed in connoctioi'i with the hioci; l apply to the block .l and need not be repeated. The only ditlercnce is that the ('onlrol oi the loop circuits for the two section: oi the block d is accon'ipliehed by a line relay it), controlled, among other in track relay of the next lj vance, rt rectly.

Referring; now to the way in "l lute and unprevenlable hi l he ad diirrespective ot' speed is given who train passes the absolute signal 9.5 at stop.

it will be noted that the section ollracl: in th block J, between the signal Z nd the insulated joints 2 marking the nh i l end of this block, is supplied with simpler; (]l' cult current under special control. li: this simplex circuit current cut oil, the a relay S on the car is tie-energized, dropping its armature 119 and opening the circuit 0t lit:

(ill

tie electro-pneumatic valve lllPV irrespective of speed. Also, the reset switch BS is incapable of energizing the electro-pneumatic valve EPV with the stop relay S deenergized. In short, the deenergization ot the stop relay S results in a brake application which is given irrespective of speed and is maintained in spite of any attempts of the engineer to release, with the exception ot course of the emergency cutout valve 112.

Explaining the situation more in detail, assume that the tower man has set up a route in interlocking territory, of which the block J is a part, and that this route set up conflicts with the route through the block J. This will have been done by the tower man in the usual way in accordance with well.- lfllOWIl practice in interlocking, the lever controlling the sigi'ial s iown conventionally as the switch 53, having been placed in the normal or stop position (shown in dotted lines), thereby breaking the energizing circuit for the line relay 40. llhe dcenergrization of the line relay l0 reverses the loop circuit current to the first or rear section of the block J, between the resistances 36 and 37 and shitts the teen ot the loop circuit current for the second or advance section of the block J from the exit to the entrance end thereof, thereby rendering this block J the equivalent of a caution block so as to enforce speed restrictions through it in the same way as previously explained. The deenergization oi the relay 4-0 furthermore breaks at its front contact 46 the circuits supplying simpler; current to the short section between the resistances 4 and 42, leaving; this section in advance of the signal Z without any simplex current. It may be explained here that this section just in advance of the signal Z will in practice be relatively short being preferably merely long enough to bring the train to a stop within the limits from the minimum speed at which the train may enter said section, here assumed to be 20 miles per hour.

With the traclrway conditions set up as just described, a train approaching the block J first receives a caution indication at the signal Z corresponding to the distant indication ilor the home signal Z and this train is obliged to reduce its speed to a ll'llllllllllll'l during its n'opgrcss through the block .l. As shown by the curve 116 just below the tracle way, the speed limits imposed. are preferably laid out so that a train observing them may come to a stop belim'e reaching; the signal Z rather than before reaching the actual exit end of the block defined by the joints 2. In other words, it is contemplated that the train under this caution control will pull up to the signal Z The signal has of course a distinctive aspect, by virtue of the shape of its blade, marker light combination, or otherwise, so that the engineer is able to recognize that at this point he is obliged to stop his train and wait, instead of proceeding at a minimum speed as he may do in the case of a permissive stop signal in block territory. Strict obedience to the in dication of this stop-and-stay signal Z is automatically enforced, because it the train should move by the signal, the stop relay is instantly deenergized, the brakes applied, and the train brought to a stop. Since the reset switch BS is ineilective with the stop relay S deenergized, the brakes can not be released and the train proceed until simplex circuit current is again applied to the short section between the resistances 41 and 42, eX- cept of course by the use of the emergency cut out valve 112.

It will thus be apparent that this invention provides, in addition to appropriate speed control in block signal territory, an absolute and positive stop control, preventing a train proceeding at any speed beyond a predetermined point. Also, this absolute stop control is obtained in conformity with the continuous inductive control principle, and utilizes a large part of the apparatus used for control in block signal territory, Such automatic and absolute stop control, therefore, serves the function of a derail and positively prevents train movement beyond a certain point and prohibits a train moving at any speed on to a conflicting route and into the path of another high speed train.

(lull-on c0utr07.lt, as assumed, the signal Z representaive of a stopandstay sin} nal, is also a semi-automatic signal, that is, is controlled by track circuits as well as manually by lever man, then this signal may be at stop due to the presence of a train ahead in the next block or within the automatic control limits for this signal. Ordinarily. the indication of this signal Z and the automatic train control entorced in conjunction therewith would be the same whether this signal were at stop due to manual control or due to the presence of another train ahead; but, while a manual. control. signal should bring; about an absolute stop, under certain circumstai'lccs it may be desirable to allow a train to proceed by this signal at stop when such stop indication is due to the presence ot another train ahead. For ere ample, it may be desired to advance the train at the signal Z to receive a clearance card, pull up to a station, platform, or take a subsidiary route. These matters are well recognized in the art, and are commonly taken care oil by the use of a so-called call-on signal. It is a characteristic of the present invention that it may be used in conjunction with the regular call-on signal, as diagram-- matically and conventionally shown Assuming that the, tower man wishes to advance train past the signal Z at stop,

after having placed his lever 53 in the reverse or clear position shown in full lines, this being possible of course it there is no conflicting route set up, the operater closes the push button 67, thereby supplying simplex circuit current to the short section just a mad of the signal Z and likewise closing the clearing circuit for the call-011 signal 59. The train may now advance at the minimum speed by the signal Z without receiving an automatic brake application.

It the lever in the tower is in the normal or stop posit-ion (dotted) to permit a second train to take a conflicting route, the energizing circuit tor the line relay is broken and "further the circuit for the call-on signal 59 and the auxiliary circuit for supplying simpler: current between the signal Z and the end of the block can not be completed, so that the pressing of the call-on push button (37 does not operate the call-on signal or energize the simplex circuit mentioned when a conflicting route is set up. In other words, the call-on push button 67 permits the clearing of the call-on signal 59 and the removal of the absolute stop restriction by the train control apparatus when the block K is occupied, but does not permit such control when a conflicting route is set up.

Attention is directed to the construction or the contacts operated by the relays 4 and l and corresponding contacts on the line relay -10. These contacts are of the makel;etoi'e-ln*ealr type, and the upper two contacts used for transferring the track or loop circuit feed from one end to the other of the second section of a block are preferably adjusted so as to make one circuit before the other circuit is broken, thereby maintaining current on this section at all times; whereas the lower two contacts used -for reversing the direction oi current flow in the first section of the block are adjusted very closely but not close enough to make both circuits siniultaneous. This close adjustment of the contacts of the niake-betore-break type,

causes them to function like a snap circuit controller so as to make and break these circuits very quickly, o that a series ot'bloeks will not be momentarily aflected. H desired, instead of the make-before-break contracts illustrated, doubletl1row snap circuit controllers operated by the signal or in any other suitable manner may be used.

In Fig. 2 directly below the block J have been illustrated curves 117, 116 and 118, similar to those shown under the block I illustrating the permissive, the actual and the apparent speed respectively, of a train when moving through the block J with its brakes applied. It should be noted that the apparent speed, as indicated by the device AG, may assume a negative value as shown at the point just before the train comes to a stop. This is possible because the decelerating factor may be in excess of the actual speed of the train; and since the ap parent speed is equal to the actual speed minus the decelerating factor, the device may indicate a negative value and the contact strips 102, 103 and extend far enough down so that an automatic brake application can not take place by reason or" a negative indication by the combined speed and deceleration indicating device AG.

in automatic train control .ystem has thus been novided which is of the continuous inductive type and manifests the exact condition of tratlic ahead on the train at all times, so that the train is released oi? a rest tion in the speed by reason of danger ions ahead as soon as these traflic conditions clear up. Restrictive speed limits are auton'iatically set up in accordance with tratlic conditions and the location of the train; but these speed limits may ac tually be exceeded within safe limits, provided the train is being decelerated at a predetermined rate, there being used a unitary device which depends tor its ope *ation on the deceleration and the speed of the train any point, regardless of the grade on which the train is running or any other local factors. An absolute stop may be enforced at an interlocking point, which absolute stop may be removed only by the tower man, either by clearin the route or by operating the usual call-on signal.

Having thus shown and described several specific f atures of a single embodiment of the present invention, this having been done ,r the purpose of illustrating the nature of the invent-ion rather than the scope thereof, it is desired to be understood that various changes, i'nodiiications and alterations may be made to adapt the invention to any particular one of the various types of signal and braking systems encountered in practice, without departing from the nature and .cope of the invention.

hat is desired to be secured by Letters Patent 0t the United States, is

it. In an automatic train control system, the combination of car-carried apparatus including a two-element three-position relay adapted to be controlled by current flowing in trackway circuits, and trackway apparatus including two distinct alternating current circuits having currents flowing therein which are preferably displaced electrical degrees under clear traiiic conditions, one of which comprises several sections employing the usual track circuit, means for changing the direction of the flow of current in one section of said track circuit and for changing the feed from the exit to theentrance end oi another section of said track circuit, whereby durin the progress of the train the car-carried relay may be energized in the normal direction, may be energized in the reverse direction and may be deenergized by controlling the track circuits only.

2. In an automatic train control system, the combination of ear-carried apparatus comprising, two influence receiving devices for detecting the flow of alternating current in two distinct trackway circuits, a two-element three-position relay having one element connected to one of said receiving devices and having the other element connected to the other receiving device, a single element reiay connected to one of said receiving devices, and trackway apparatus including two distinct circuits having alternating currents flowing therein, one of which comprises the usual track circuit, said single element relay being maintained energized in response to current flowing in the other of said trackay circuits, means for controlling said track circuit to cause said two-element relay to be energized in a normal direction, in a reverse direction and to allow it to be deenergized without deencrgizing said. single element relay, whereby four distinct controls of continuous character are transmitted by two distinct trackway circuits.

3. Car-carried apparatus for automatic train control systems of the type in which alternating current in the usual track circuit and in another trackway circuit are em ployed to energize a three-position relay on the railway vehicle in a normal direction, in a reverse direction or allow it to be deenergized comprising, a three-position relay, a speed responsive device, means for setting up three different speed limits it said relay is energized in a normal direction, in a reverse direction or is deenergized, respectively; means for automatically applying the brakes if the speed of the vehicle exceeds the permissive speed, and a stop relay normally maintained energized by current flowing in said another trackway circuit which is deenergized causes an absolute stop by an application of the brakes regardless of the speed of the vehicle.

4-. Car-carried apparatus for automatic train control systems of the type in which alternating current in the usual trackway circuits and in another trackway circuit are employed to energize a three-position relay on the railway vehicle comprising, a twoelement three-position relay, a device for indicating an apparent speed value depending on the speed of the vehicle and the deceleration ot the vehicle, means for set-ting up three different speed limits it said relay is energized in a normal direction, in a reverse direction, or is deenergized respective ly, means for automatically applying the brakes if the apparent speed of the vehicle exceeds the permissive speed, and a stop relay normally maintained energized by cur rent flowing in said another trackway cireuit to which if deenergized causes an absolute stop by an application of the brakes regardless ot the speed of the vehicle.

5. Car carried apparatus for automatic train control systems of the continuous type comprising, a two-element three-position relay and a single element two-position relay, means for energizing one element of the three-position relay in responseto alternatin g current flowing in the usual track circuit ahead of the train, and means for energizing the other element of said three-position relay and said single element relay in response to alternating current flowing in another trackway circuit, whereby the three-position relay may be energized in the normal position, in the reverse position, and may be deenergized in response to the direction of flow and the absence of current in the usual track current without deenergizing said single element relay, and whereby the single element relay is deenergized in response to absence ofi current in said another circuit.

6. Car-carried apparatus for automatic train control systems of the continuous inductive type comprising, inductive influence receiving means responsive to the flow of alternating current in the usual track circuit ahead or the train, another inductive influence receiving means adapted to respond to the flow of alternating current in another circuit, and means for giving four distinctive controlling conditions in response to the phase relation and the absence of one or the other of said trackway currents.

7. Car-carried apparatus for automatic train control systems of the continuous inductive type comprising, inductive influence receiving means responsive to the flow of alternating current in the usual track circuit ahead of the train, another inductive influence receiving means adapted to respond to the flow of alternating current in another circuit, and means controlled by said influence receiving means for effecting four different restrictions upon the movement of the vehicle in response to the phase relation and the absence of one or the other of said trackway currents.

8. Car-carried apparatus for automatic train control systems of the continuous inductive type comprising, inductive influence receiving means responsive to the flow of alternating current in the usual track circuit ahead of the train, another inductive influence receiving means adapted to respond to the flow of alternating current in another circuit, a combined speed and deceleration indicator for indicating the apparent speed consisting of the actual speed of the vehicle minus a decelerating component, a brake control device, and means governed in accordcuits for actuating said brake control device when the apparent speed of the vehicle is excessive.

9. Car-carried apparatus for automatic train control systems comprising, a shaft driven by an axle of the vehicle, a, mass associated with said shaft and rotated therewith, an indicator responsive to the centrifugal force minus the deceleration force acting upon said mass through said shaft, a b 'ake control device acting on the usual airbrake system, and means governed in accordance with trafiic conditions ahead andicooperating with said indicator for automaticallyactuating said brake control device if the vehicle is moving at excessive speed and is being improperly controlled.

10. Brake control apparatus acting upon the usual air-brake system of the vehicle for applying. the brakes thereof whendeenergized, means governed in accordance. with traflic conditions ahead for maintaining said brake control apparatus energized, saidilast mentioned means also including a device having. a mass rotated in accordance with the speed of the train, said device being, responsive to. the difference between the centrifugal force and the rotative decelerating force acting upon said mass, and means for deenergizing said brake control apparatus if said device indicates an excessive value, whereby thebrakes are automatically applied if the speed is excessive for the particular trafiic conditions existing ahead unless thetrain is beingadequately decelerated.

11. Car-carried apparatus for automatic train control systems of the continuous inductive type comprising, inductive influence receiving. means responsive to the flow of alternating currentin the usual track: circuit ahead of the train, anotherv inductive influence receiving means adapted to respond to the. flow of alternating current in another circuit, a brake control device acting on the usual air-brake system of the train for applying the brakes if deenergiced, means governed in accordance witlrthefiow of current in said trackway circuits including said. receiving means for determining the limiting speed at which the vehicle may travel. and which: deenergizes vsaid brake control :device if the vehicle exceeds this limiting speed in response to absence of current in. oneaof said :trackway circuits, and, which deenergizes thebrake control device regardlessof the speed of :the train in response to the absence of current in both of said trackway circuits.

121x11. automatic train control system. of the continuous inductive type comprising,

means forindicating the flow ofalternating current 111- the usual track circult ahead of the tram, means partly on the vehicle and partly along the trackway for setting up a standard alternating current on a railway vehicle with which the track circuit current may be compared to determine the phase relation of said track circuit current, a twoelement relay on the vehicle having one element energized by said standard and having the other element energized in response to said track circuit current, a brake control device acting on the usual air-brake system of the vehicle which applies the brakes if deenergized, means governed by said relay including a speed responsive device for deenergizing said brake control device ii the vehicle exceeds predetermined speed limits depending upon whether said relay is energized in the normal direction, in the reverse direction, or is deenergized, and vehicle carried means for deenergizing said brake control device regardless of the speed of the vehicle upon interruption of the supply of said standard alternating current.

13. Trackway apparatus for automatic train control systems for railways divided into blocks comprising, track rails divided by insulated joints into blocks having two sections also divided by insulated joints, means forapplying simplex current consisting of current flowing in the two rails in multiple in each of said sections in automatic signal territory, means for supplying track circuit current to the exit end of the first section of a block ofnormal and reverse polarity when the block in advance is unoccupied and occupied respectively, means for supplying track circuit current to the, exit end and the entrance end of the second section. of each block of normal polarity when theblock in advance is unoccupied and occupied respectively, and track relays governed by said track circuit currents.

14;. Car-carried apparatus for automatic train control systems comprising, a normally energized brake control device acting :on the usual air-brake system ofthe vehicle, means governed in accordance with tra'liic conditions ahead for deenergizing said brake control device if the speed of the train is dangerous and is not decreasing including a shaft rotated in accordance with the speed of the train, a mass associated with said shaft and rotating therewith, an indicator, and means for shifting said indicator in accordance with the centrifugal force and the rotative decelerating force acting on said mass.

15. Trackway apparatus for. automatic train control systems of the continuous inductive type operable in automatic signal and interlocking territory comprising, a partial simplex circuit including two track rails in multiple at the approach to interlocking territory, a semi-automatic stopand-stay signal operated in accordance with tratlic conditions ahead and in accordance with whether a conflicting route is set up and assuming an unfavorable indication condition if either traiiic conditions aheat are dangerous or a conflicting route is set up, means for energizing and deenergizing said partial simplex circuit under clear and danger indication conditions of said signal respectively, a normally inactive call-on signal, and means for independently energizing said partial simplex circuit and for placing said call-on signal in its active con dition only ope ative if no conflicting route has been set up.

16. Trackway apparatus for automatic train control systems of the type in which the usual track circuit current ahead of the train is detected to manifest on the train traffic conditions ahead of the train comprising, a section of track rails efl'ectively separated from the rest of the track by in sulated joints, a track relay responsive to the potential across said rail, and means for supplying a potential across either end of said track rails, whereby if the source of supply is connected to the exit end of said t'ack rails the presence of current in the track rails is manifested on the train, and if the source of supply is connected to the entrance end the flowi of current in the track rails is not manifested on the train because the track current does not flow ahead of the front axle thereof, whereby the track relay always responds properly to the flow of track circuit current in said relay, but the presence of track circuit current is detected on the train only when fed from one particular end of the section.

17. Trackway apparatus for automatic train control systems of the type in which the usual track circuit current ahead of the train is detected on the train to manifest on the train traffic conditions ahead of the train comprising, a trackway divided by insulated joints into blocks each having two sections each provided with the usual track relay, means for supplying track circuit current on the two sections of a block of predetermined polarity under predetermined conditions, and means including said first; mentioned means for supplying current of reverse polarity to the first section and supplying current to the second sec tion in a manner that it operates its corresponding track relay properly, but its presence is not manifested on the train when the next block in advance is occupied.

18. Trackway apparatus for automatic train control systems of the type in which the usual track circuit current ahead of the train is detected on the train to manifest the conditions of traflic ahead comprising, a traekway having a section divided by insulated joints, a track relay connected between the rails of said section, means for supplying current to the exit and entrance end of said section when traflic conditions ahead are clear and dangerous respectively, whereby the track relay will function properly regardless of whether the current is supplied from the exit or the entrance end of said section, and whereby the presence of current in the track rails is manifested on the train only if the current is supplied to the exit end of the section.

19. In an automatic train control system, the combination of means partly on the vehicle and partly along the track and acting through an intervening air gap to transmit control influences to the vehicle in accordance with traffic conditions ahead, n-or maliy inactive brake control device of the type which once actuated remains in its active condition until restored, means for actuating said brake control device if the vehicle is not properly decelerated when moving at a predetermined speed under pre determined tl:.iii6 conditions ahead, and manually operable means for restoring said brake control device which inflicts a penalty upon the engineer each time it is operated.

20. In an automatic train control and signaling systcn'i for railroads; the combination of means partly on the vehicle and partly along the trackway for transmitting control influences in automatic block territory corresponding to clear, caution or danger when traiiic conditions ahead are clear, caution or danger, and effective to transmit influences corresponding to that of the usual call-on slgnal at the approach of the train to an interloclring point in response to track conditions set up at such interlocking point; and cab signaling means responsive to such influences for giving cab indications in re sponse to traflic conditions ahead in automatic block territory and to track conditions set up at such interlocking point.

21. In an automatic train control and signaling system for railroads, the combination of means partly on the vehicle and partly along the traclrway and effective during the progress of the vehicle along the trackway for transn'iitting control influences in automatic block territory corresponding to clear, caution or danger when traiiic conditions ahead are clear, caution or danger, and effective to transmit influences corresponding to that of the usual call-on signal at the approach of the train to an interlocking point in response to track conditions set up at such interlocking point; and cab signaling means responsive to such influences for giving cab indications in response to trafiic conditions ahead in automatic block territory and to track conditions set up at each interlocking point.

22. Car-carried apparatus for automatic train control systems of the continuous inductive type comprising, inductive influence receiving means responsive to the flow of alternating current in the usual track circuit ahead o1 the train, another inductive influence receiving means adapted to respond to the flow of alternating current in another circuit, and means for giving four distinctive cab signal indications on the train in response to the phase relation and the absence of one or the other of said trackway currents.

23. In an automatic train control system, the combination of car-carried apparatus comprising a relay, amplifying means having its output circuit connected to said relay, coils carried by the vehicle directly in front of the first axles thereof connected so as to have voltages induced therein due to current flowing in one direction in one rail and in the other direction in the other rail cumulatively and connected to the input side of said amplifying means, and traekway apparatus for etl'ecting energization of said relay comprising, a section of track having a track relay connected across the rails thereof responsive to the current for eli'ecting energization of the first mentioned rclay, and means for applying current to either end of said section, whereby said track relay will respond to the presence or absence 0]": a train in said section and the first mentioned relay can only detect current 30 in the tracliway provided the train is headed toward the end from which said track section is fed and there is no other train ahead in that section.

In an automatic train control system the combination of car-carried apparatus comprising a relay, amplifying means ha ving its output circuit connected to said relay, coils carried by the vehicle directly in front of the tirst axles thereof connected so as to have voltages induced therein due to current flowing in one direction in one rail and in the other direction in the other rail cumulatively and connected to the input side of said amplifying means, and tracl-nvay.

apparatus for effecting cnergization of said relay for a particular direction of movement of the train under predetermined traflic conditions con'iprising, an insulated section o't trackway, and means controlled automatically in accordance with traitic conditions tor applying current ot a character capable of causing said relay to assume its energized position across the rails at one end or the other of said section.

in testimony whereof I hereby all ix my signature.

OSCAR H. DIOKE.

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