US1743810A - Train control - Google Patents

Description

Jan. 14, 1930. F. L. DODGSON 1,743,810

TRAIN CONTROL' Original Filed Jan 28, 1924 2 Sheets-Shee 1 \k I WNVE NTOR A 'TTORNEY Jan. 14, 1930.

I39-Cloed belowyZZ M.P.H.

F. L-. DODGSON TRAIN CONTROL Original Filed Jan. 28. 19,24 25heets-Shee 2 I26- Closed Ser. 80 Emerq.

Eng. Biqke Valve 1 ATORNEY/ inflicting Patented Jan. 14, 1930 NITE,- STATES A Prion FRANK L. nonesom-ornocnnsrnn, NEW" YORK, ,AS'SIGNOR To" GENER-AL"RAILWAY SIGNAL COMPANY, or noor-rnsrnngnnw'roan- TRAIN CONTROL Original application filed January 28, 1924, Serial N 04 639,020, Divided and this application 'filedvoctober 2?, 192a SerialiNo. Mano.-

This invention relates to train controlsystems, and more particularly to means for stimulating the vigilance of the engineer and his obedience to the wayside signals, and for penalty if the en 'ineer does not manually apply the brakes before the speed 01" the train is excessive.

In applying-automatic train control apparatus to railroads it is considered desirable to employ such apparatus as will afford an additional safeguard over that obtainable by a careful, alert and prudent engineer rather than as a substitute for such engineer. In other words, it is desirable to have the safety of the traindepend on both the automatic train control apparatus and the engineer, ratherthan eitherof these two standing alone.

One object and feature of thepresent invention contemplates the provision of a simpie and direct way of determining when an adequate brake application, such as the usual service application, has been effected so far as manual control is concerned,it being desirable to know if an adequ'atebrake application has been initiated and will take place,

because a certain amount ottime transpiresbetwcen the completion of the manual control of a brake application and the brake application itself, this determination or manifestation of the appropriate manual control of a brake application continuing onlyso long as the manual control 18 und sturbed and is allowed, in time, to consummate the brake application. A further object of the present invention resides in the provision of means for inflicting apenalty upon the engineer if he himself does not properly control the train by applying the brakes when "entering a danger-zone, thispenalizing means being rendered ineffective without suppressing automatic operation of a suitable auto matic brake applying device when an automatic brake application is initiated after a manual brake applicationhas beeninitiated. Other objects, purposes and characteristic features of the invention will appear as the description thereof progresses.

This application is a division of my prior application, Serial No. 689,020, filed January lar block to which thepresent train control apparatus is applied being illustrated;

-Fig.- 2 illustrates in a diagrammatic and conventional manner the car-carried equipmentof the traincontrol system just referred to. v

The specific embodiments of the'invention as illustrated in the drawings consist of a .novelarrangement for. penalizing the engineer-lf-he does not attend to his duty as applied to train controlsystem of the continuous inductivetype.

Tmckway apparatus j oi'ntsQ into blocks in'the usual manner, only the block '1 and the adjacent ends. of two other'blocirs Hand J being shown. Since the varicusblocks are the same, like'parts of 'eachblock have beenidesigna'ted by like reference characters havingdistinctive exponents. Although the trainv control system embodying the present invention may be used in connect on with wayside signals of any type,-. such. as semaphore signals, position light signals and color light signals, ithas fOPCOIlVGIllBDCQ been shown applied to a system employing semaphore signals Z, which havebeen shown conventionally without ilflust'ratingany particular form of their wellknown control circuits nism.

Each of the blocks is, provided with a suitable source of alternating current energy at and control mechatheeXit end-thereof, illustrated as a track transformer 3, and asuitable track relay t at its entrance end. This forms the welllmown closed track circuit which needs no furthendiscussion. r

In addition to the usual track circuit curprovided.

rent flowing in the rails of a block, there is provided a circuit to permit the flow of alternating current in the two rails in multiple in the same direction, which for convenicnce will hereinafter be referred to as the simplex circuit. In order to permit the flow of current in this simplex'circuit, including in multiple the rails of a portion of a block or the rails of the entire block, three balancing resistances 5, 6 and 7 are bridged across the rails at the entrance, at an intermediate point, and at the exit end of each block respectively. In order to supply alternating current energy to these two circuits, a transmission line including wires 8 is strung along the track, the energy for the simplex circuit of each block being supplied by the transformer 9;

In order to cause the simplex current to flow in one particular direction as compared with the direction of flow of the loop circuit or track circuit current along the entire length of the block at one time, and cause it to flow in the opposite direction through a portion of the block only at other times, front contacts, as 12 and 13 operated by the track relay of the block next in advance, as 1 are Referring to the block 1, by looking at the circuits governed by these two front contacts 12 and 13 it is readily apparent that if the track relay 4 is in its normal energized condition, current is permitted to flow through the two rails in multiple in the block 1 from the middle point of the balancing resistance 7 to the middle point of the balancing resistance 5, and that when this track relay 4 is de-energized, current will flow in a reverse relative direction from the middle point of the balancing resistance 5 through the two rails in multiple to the middle pointof the balancing resistance 6 located at an intermediate point in the block. In practice the constants of these simplex circuits with respect to the constants of the loop circuit including the track transformer are so chosen that the phase displacement between these two currents is as large as possible or practical, so that if these currents are detected by suitable apparatus on the train, that is, amplified and applied to a two element or three-position relay, this relay produces a torque in one direction orthe other depending on the phase relation between these two currents and in turn on the position of contacts 12 and 13 of the track relay ahead.

Influence communicating means.-On the vehicle, which has been conventionally shown by axles 15 and wheels 16, is a pair of loop or track circuit influence receiving elements LE, comprising cores 17 terminating in pole pieces 18, each having a winding or coil 19 thereon. The coils 19 are connected in series in a manner so that the voltages induced therein, due to currents flowing in opposite directions in the two rails, are cumulative and these coils are connected to a suitable amplifying device AL (not shown in detail) which comprises thermionic or vacuum tube amplifiers of well-known commercial or special construction. The output lead wires of this amplifying device AL are connected to the winding LR of the control relay R.

At a suitable point on the railway vehicle is a simplex element SE, which comprises a long core 20 terminating in enlarged pole pieces 21 and having a coil 22 thereon for detecting the flow of simplex current in the two rails in multiple. This coil 22 is connected to the input side of a similar amplifying device AS which has its output terminals connected to the other winding SR of the control relay R. It is thus apparent that, with currents flowing in the loop circuit ahead of the train and in the simplex circuit under the train and having a certain phase displacement, currents will be supplied by the two amplifying devices AL and AS of a similar phase relation and will cause the relay R to be operated in a certain direction, and that, if one of the track currents has its relative current flow reversed, the control relay R will be operated in the opposite direction; and that, if one of these currents is eliminated or absent, the relay R will assume its deenergized or biased position. This relay R is of a suitable three-position biased type, and provided with contacts 28 and-29, which control the high cam starter magnet CSH and the low cam starter magnet CSL of a suitable speed restricting apparatus to be described hereinafter, the currents for energizing these two magnets being derived from a suitable source of energy such as a battery. The battery is not shown, but B designates a connection to one terminal, and C a connection to the other terminal.

Train performance speed characteristics. Directly over the block I of the trackway shown has been illustrated a solid line curve 23 which shows the permissive speeds at which the train may run without exceeding the speed limit set up by the car-carried apparatus to be described hereinafter. It will be noted that this curve has a drooping characteristic in the first part of the block I, continues as a straight line corresponding to a constant speed for a distance, and then again droops until it reaches a low constant speed limit of 20 miles per hour. This first droop in the curve is caused by the high cam to be described hereinafter, and the second droop in the curve is due to the low cam. The particular block I in connection with which these curves have been shown is assumed to be either a down-grade block or a block in which the braking ability of the train is poor for some other reason, and there fore requires a longer distance of movement to reduce the speed of the train to a certain value than the distance in which one or the other'of these cams run from a maximum to a minimum speed position.-

The dot-and-dash line 24 illustrated shows the speeds of the train atdifferent' points along the track if the brakes are applied when the train enters the block I at a speed of about 65 miles per hour. It is thus noted that, with the character of block assumed, even though the engineer does apply the brakes upon entering the block I, he will be unable to stay below the permissive speed line set up by the high cam, this beingshown by the fact that the dot-and-dash performance curve 24 crosses solid permissive speed curve 23 at the point 25. Also, if the engineer releases the brakes when he gets below the 40 miles per hour limit, and proceeds at a constant speed until he reaches the point X in the block, he will not be able to stay below'the permissive speed curve enforced by the low cam, even though he applies the brakes when passing the point X, as illustrated by the fact that the dot-and-dash performance curve 24.

crosses the solid permissive speed curve 23 at the point 26. The continuation of the first droop in the 'dot-and-dash line24 has been shown bya dotted line 27 which illustrates the speed at the various points in the block that the train assumes 'if-the brake application is continued, that is, shows-the brake performance curve for a complete stop fromhigh speed. It should be understood that the particular speed-distance curves illustrated apply onlyto the particular set of conditions which have been assumed in order to bring out certain advantageous features of the present invention and that these curves are not necessarily characteristic of train performances for all'trains in all blocks or portions of the railroad. The speed-distance curves of permissive speed and train performances are merely typical and are not intended to be accurately shown, being susceptible of wide variation in practice to con 1 form with the different speed limits required for different kinds of equipment and varying practices on railroads.

Uar-cawe'ed apparatus of Fig. 2Pe1rn-issioe and actual speed meckam'sm.+Sinoe the high cam and low cam operating mechanisms are substantially the same, except asto theparticular shape of the cam and the speed limit enforced, the high cam and its associated mechanism only has been illustrated. The influence communicating apparatus for controlling both the high and the low cam ing a cam .39 fixed thereon. The arm 36 is urged upwardly by a compression spring .41, disposed around a guide 42, so that if the cam starter magnet .CSH isde-energize d the pinion 35 is urged upward into meshed relation with the mutilated gear 37, whereupon movcment of the vehicle alongtlie track gradually turns the cam shaft 38 and its associated cam '39. In order to return the shaft 38 backto its normal position in the event that the cam starting magnet CSH is again energized, a gear sector 43, aivoted at 44, engages a pinion on the camshaft 36; and this gear sector 43 is biased to an intermediate position by initially tensioned springs 46. 1

On the shaft 30 is mounted a centrifugal speed-responsive device G of usualand wellknown construction, which'comprises a collar 47 pinned to the shaft 30,- and another similar but grooved collar 48 slidably mounted on this shaft, these collars being coupled together by links 49 having a weight 50 at their pivotal junction, and a compression coil spring '51 between these collars.

Parallel and preferably adjacent to the shaft 38 is a speed shaft 53 to which is pinned a bifurcated arm54 engaging the groove in the collar 48. Pinned to this shaft 53 is a speed arm 55 and speed cams 56 and 76. An increase in the speed ofthe shaft 30 causes the collar 48to move in response to the centrifugal force acting on the weights 50 in opposition tothe spring 51, so that the speed shaft 53 and speed arm 55 and the speed cams '56 and 7 6 are moved in a clockwise direction. To. the lower and free end of the speed arm 55 is pivotally secured one end of a floating lever 57 which carries a roller at its other end engaging the camsurface of the cam 39. At an intermediate point on thefioating lever 5? is pivotally secured one end of a'link58 which has its other endpivotally secured to an eccentrically located pin on the sector 59, which sector is pivotally supported on a pin 60. Adjacent the sector 59 is secured a spring finger 61 which has a roller 62 pivotally secured thereto which rides on the cam surface of the sector 59. This spring linger 61 normally cooperates with a stationary finger 63 to control a suitable circuit more clearly described hereinafter. Adjacent to the speedcam 56 are provided similar contacts 64and 65 which cooperate with this cam 56. Likewise contacts 139 are provided to cooperate with the cam 7 6.

By looking at this structure it will be readily understood that the sector 59 will move in a clockwise direction in response to movement of the'cam 39 from its normal position.

It will also appear that this sector 59 moves in the same or clockwise direction in response to an increase in the speed as indicated by the governor G, so that either an increase in speed or movement of the cam 49 from its normal position tends to move the sector 59 in the same direction and eventually allows the roller 62 to ride into the contracted or reduced portion of this sector, thereby opening the contacts 6163. In other words, after the cam 39 moves from its normal position, the speed of the train must be correspondingly reduced to avoid opening of these contacts. Also, it will be noted that decreasing the speed of the train to a certain value, assumed to be two miles per hour, causes the cam 56 to close a circuit at the contacts 64 and 65 and the contacts 139 are adapted to be closed by the cam 76 when the speed of the train is below 22 miles per hour, all for reasons more clearly described hereinafter.

Brake applying de'viea' The present train control system assumes the provision of means to automatically apply the brakes of the train under certain conditions of the carcarried apparatus. In order to accomplish such a brake application, a brake applying device has been illustrated conventionally by the electro-pneumatic valve EPV. This device EPV may vent the brake pipe directly,

tion of this apparatus is deemed unnecessary.

This electro-pneumatic valve EPV is provided with contacts 104 and 188 for the purposes explained hereinafter.

The usual engineers brake valve has been shown conventionally, and-is provided with a handle 66 and with a suitable contact sector 67 which is adapted to close a circuit when this valve is in the service and emergency positions.

0 pemtion.

Normal clear 00nde't2'0ns.-Under normal 7 clear traffic conditions both the high and the low cam assume their highest speed position 3 which corresponds to the maximum permissumed to be as shown by the positions of the various devices in Fig. 2 of the drawings, the electro-pneumatic valve EPV is energized by a stick circuit which may be traced as follows :Beginning at the terminal B of a suitable source of energy, wire 100, contacts 61 and 63," wire 101, winding of the EPV, wires 102 and 103, front contact 104 of the EPV, wire 105, back to common return wire 0.

This circuit maintains the valve EPV in its normal inactive position, allowing the train to proceed in accordance with the manner in which it is governed by the engineer.

If the engineer should allow the speed of the train to exceed the maximum limit of 65 miles per hour, the action of the governor Gr closing a pick-up circuit for the EPV, comprising wire 100, contacts 61 and 63, wire 101, winding of the EPV, wires 102, 106 and 106, contacts 65 and 64, wire 107, back to common return wire C. The completion of this circuit again picks up the EPV and this permits the engineer to release the brakes manually if he so desires. This requirement of bringing the speed down to practically a stop after exceeding the maximum speed limit, before the brakes can be released, is considered to be a penalty, and is assumed to make him more vigilant in the control of the train tcli avoid such a brake application and pena ty.

The penalty above described for exceeding the maximum speed limit is optional; and if desired, by a rearrangement of the circuits which will be very evident, this penalty may be omitted so far as the maximum speed limit is concerned, by making the electro-pneumatic valve EPV non-stick for clear traffic conditions only by simply providing a shunt for its front contacts 104 closed so long as the main car relay or the high cam starter magnet CSH is energized. In fact, to conform with the requirements of some railroads, it

may be found expedient to omit the maximum I speed limit under clear traflic conditions altogether, permitting the train to run, so far as automatic control is concerned, at any suitable speed under clear traflic conditions.

Caution eondz'tz'ontspeecl not excessive) Let us assume that a train equipped with the car-carried apparatus shown in Figs. 1 and 2 is moving in the block H in the normal direction of traflic as indicated by the arrow, and that the block J is occupied by another train. With the block J occupied, the track relay 4 is de-energized, thereby causing the simplex circuit between the entrance to the block I and the point X to be reversed. Consequently, when the following train in question enters the block I, the control relay R will swing to the reverse position, thereby dc-energizing the high cam starter magnet CSH, but maintaining the cam starter magnet CSL energized. The high cam 39 is thus initiated and is gradually rotatedin one direction or the other, depending on whether the train is running pilot or tender first, thereby gradually reducing the permissive speed, as indicated by the curve 23 in Fig. 1. If the actual speed of the train does not exceed the permissive speed limits at any point, no automatic brake application will take eifect, it being'assumed for the present that the permissive speed limdoes not'allow the speed of the train to exceed at any point these permissive speed limits, no automatic brake application takes efiect.

Caution condte'on5'peed ewcessive.The

gradually decreasing permissive speed limits,

indicated by the curves 23 and the solid lines in Fig. l, are produced by movement of the two cams and since these cams are driven 1 V from the car wheels, the curves of permissive speed set upare the same for each block or control point on the railroad, whether on an up-grade or on a down-grade; and these permissive speed curves 'are the same for the particular lOCOIDOtlVQGLlUlPPBCl whether running alone or pulling a long or a short train.

' As previously explained, there-sometimes are permissive speed limits'arbitrarily and auto- -matically established, 1t being assumed that portions of track where it is not possible for all trains to keep below'the permissive speed limits at all points in a caution block,'u1'1less the train is handled and braked in some unusual or peculiar manner.

'In conformity with the theory of traincontrol on which this invention is based, it is desired to stimulate and enforce vigilance on the part of the engineer in obeying the indications of the blocksignals,-particulai'ly the caution signal. One Way ofmaintaining each time heallows his train to exceed'the the engineer, in order to avoid" such penalty will keep vigilant and handle his train safely.

Such an ex edient for maintainin vi ilance i b b is found objectionable in many instanceabecause it is difficult for the engineer to observe the arbitrary speed limits for all blockswithout special manipulation. Qbviously any penalty imposed should -be one fa r'to the engineer and preferably one whichthe engineer can readily avoid i by exercising ordinary prudence and care in the handling of the In view of theseconsiderations, itisproposed in the present invention to provide a I penalty which the engineer may avoid in either of two ways, namely, maintaining the speediof his train at all'timesbelow'the arbitrary speed limits, or prior to exceeding such arbitrary speed limit, manifesting his vigilance by initiating a brake application. It is thought thatlwith such'arrangement the eng'ineer may handle his trainin theregular responding control point, at which the cam is started, will not maintain the 's'peed' of the train below the permissive speed limits, if the 'train'enters the blockat its "normal running maximum speed, let us assume a train, running its normal speed of about 62' miles per hour; enters the block'l, and suppose for the first' set of conditions tliatt-he engineer is asleep, negle'ctful, or'otherw'ise fails to take appropriateaction in obedience to the caution signal. As the train continues at themaXr mum speed limit prescribed by the cam, the speed' distance contacts 6163 open, and deenergize the electro-pneumatic valve 5 and since thi's'va'lve is energized bya stick circuit, once 'de energized, it remains tie-energized until picked; up by closure of contacts 6 l.65 at a speed of 2 m'i'les'per hour, or substantially proceed. This constitutes the; penalty for lack of "vigilance.

Suppose, howeverfthat the engineer sees and recognizes the caution indlcationof the g block signal" at the entrance to the block I, such vigilance is to penalize the engineer and.rea'liZingthe'high speed at which his train is'traveling,- moves the handle of his regular engineers brake valve to the service .p'ositionfor the purpose of applying the brakes, this. movement of the brake valve occurring before the; permissive speed limits are exceeded. sd long at the engineers brake valve is in, the service position, it is obvious that the brakes arebeing'applied at the service rate asrapidly' as consistent with safety and slewdo-w'n' the trainas'effectively as an autoniat'iciapplication'of the brakes. The engineerhas nuanifested in this'vvay his vigilance, and the penalty may be suppressed. It is not necessary in' the interests of safety to have thebrakes fully applied at the instant the permissive speed limits are exceeded, since these permissive speed limits are selected and set up on the assumption that the starting of abrake application at that particular point and speed will bring the train to a stop at the desired point. Accordingly, it is sufficient if the engineer gets his brake valve in the service position before exceeding the speed limits, the time taken to get the brakes fully applied being no longer than that required for an automatic application, and due allowance for this time is made in determining the permissive speed limits.

Applying these principles to the specific system shown, wherein it is deemed practical to require the engineer to maintain the engineers brake valve in the service position as long as the speed of the train is excessive, a penalty suppressing relay PR has been provided which makes it possible for the engineer to suppress or avoid the penalty provided he moves his brake valve to the service position before an automatic brake application is initiated and keeps it there.

Assume that the permissive speed is gradually decreasing and the speed of the train is such that it is just about to exceed the permissive speed limit. If now the engineer moves his valve to the service or emergency position before the device EPV is de-energized, a pick-up circuit for the penalty suppressing relay PR is completed which may be traced as follows :-beginning at the terminal B of a battery, wire 137, front contact 138 of the device EPV, wires 140 and 141, winding of the penalty suppressingrelay PR, wire 142, contacts 126127, wire 143, back to the common return wire C. With this circuit completed the relay PR picks up and completes a stick circuit through its front contact 144 which may be traced as follows beginning at the terminal B, wire 145, front contact 144, wires 146 and 141, winding of the relay PR, wire 142, contacts 126-127, wire 143, back to the common return wire C.

If now the speed of the train exceeds the permissive speed set up by the cam 39, an automatic brake application will be initiated by the device EPV. This application may however beineffectual since the equalizing reservoir has alreadybeen partially vented by manual movement of the brake valve to the service position. Even though the device EPV has assumed its de-energized position and has opened contacts 138, the penalty suppressing relay PR is nevertheless maintained energized through its stick circuit including contacts 144, so long as the engineers valve is kept in the service P08111011; As soon as the train speed has been reduced to 22 miles per hour, contacts 139 are closed and the device EPV is picked up through the following circuit :--beginning at the terminal B,

wire 100, contacts 61 and 63, wire 101, winding of the device EPV, wires 102-106 and 147, contacts 139, wire 148, contact 149, wire 150, back to commonreturn wire C. After the device EPV is once picked up, it will again be stuck up through its stick circuit including contact 104, so long as the permissive speed set up by the cam is not exceeded.

Had the engineer put his brake valve in the service position after the brake applying device EPV was de-energized in response to excessive speed, the penalty suppressing relay PR- could not have been picked up, because the pick-up circuit including the contacts 138 was not intact, and consequently a penalty would have been inflicted requiring the engineer to reduce the speed to not more than 2 miles per hour before the device EPV could have again been picked up. Reducing the speed to 2 miles per hour causes closing of contacts 64 and 65 and energization of this device EPV. In other words, in this arrangement the engineer, if alert, may anticipate the automatic action by a partial or complete brought down to a low speed, assumed to be 22 miles per hour. Keeping the brake valve in the service position for an extended period of time may result in an unnecessary reduction in brake pipe pressure; but in some cases and under some circumstances, this may not be objectionable, thetrain frequently being braked down to a speed less than a suitable control speed, such as 22 miles per hour, before the brake pipe has been materially over reduced.

Danger condz'tz'om-W'hen the train enters the block J assumed to be occupied by another train, the loop circuit influence receiving coils 19 will be deprived of trackway energy and the control relay R will assume its de-energized position regardless of whether or not simplex circuit current is flowing in the block J, because the track or loop circuit current is shunted away from the train in question by reason of the train ahead. Assume now that, with the train in question moving in the block J, the other train heretofore mentioned moved out of the block J into the following block. Under this condition the loop circuit apparatus of the train in question again receives energy from the loop circuit ahead of the train, and the simplex Winding of the relay R a current of reversed'relative direction of flow therein, so that the relay Ragain assumes the reversed position and permits the train to proceed at an intermediate speed of d0 miles per hour, for example, as indicated in the diagram, in Fig. 1, provided the train in question is to the rear of the point X for the block J. It is thus noted that the train control apparatus may be released of its restricting control at an intermediate point in a danger block as soon as track conditions ahead become favorable, this also being true when a train moves in a caution block and such block clears up in the meantime.

In the specific form of the invention shown and described the primary purpose is to stimulate and maintain vigilance on the part of the engineer, requiring him, under penalty of being obliged to come to practically a full stop instead of being restricted to a limited speed, and to recognize and observe the indications of the block signals, particularly the caution signal. Further, the engineer is penalized if he does not control his train properly and in accordance with the indications of the wayside signals, and means is also provided for suppressing the penalty ordinarily inflicted upon the engineer provided he has initiated a manual application of the brakes before an automatic brake application has been initiated, this penalty suppressing means requiring the engineer to keep his brake valve in the service position permanently until the speed of the train has been reduced to a safe value, which has been taken at 22-miles per hour.

Having thus shown and described one specific embodiment of the invention as applied to continuous inductive train, control systems, the specific disclosure made has been shown to illustrate the motive of the invention rather than its scope, and it is desired'to be understood that various changes and modifications may be made to adapt the invention to other types of systems without departing from the spirit of the invention or the idea of means underlying the same.

'lVhat I claim is 1. An automatic train control system comprising, a brake control device, means for automatically actuating said brake control device, means infiict-ing a penalty each time the brake control device is actuated, and means for restoring said brake control device to normal without inflicting said penalty, and means permitting said last mentioned means to be made active and eifective only if the engineers brake valve is placed in the service position and is kept in such position until the train speed has been reduced to a safe value.

2. An automatic train control system com-,

prising, a brake control device, a permissive peed device, an actual speed device, means for actuating said brake control device if the actual speed exceeds the permissive speed, means for restoring said brake control device effective only after a penalty has been inflicted, and other means for restoring said brake control device without penalty effective only if the speed of the train has been reduced to a certain value as a result of a maintained manual application of the brakes initiated prior to the automatic actuation of said brake control device.

3. An automatic train control system, comprising a brake controldevice, a permissive speed device, an actual speed device, means for actuating said brake control device if the actual speed exceeds the permissive speed, means for restoring said brake control device eifective only after a penalty'has been inflicted, and other means for restoring said brakecontrol effective if and only if the e11 gineers brake valve has been placed in the service or emergency position before said brake control device was actuated and has been kept there until the speed of the train is no longer excessive.

4. An automatic train control system comprising, a brake control device, a permissive speed device, an actual speed device, means for actuating said brakecontrol device if the actual speed exceeds the permissive speed, means for restoring said brake controldevice effective only'after a penalty has been inflicted, and another. means for restoring said brake control device to normal effective if and only if the engineer has placed the brake valve in a brake applying position before the brake control device was actuated and has kept it there until a predetermined effect has been produced.

5. An automatic train control system comprising, a brake control device, means for automatic'ally actuating said brake control clevice, means inflicting a penalty each time the brake control device is actuated, means for restoring said brake control device to normal without inflicting said penalty, and means permitting said last mentioned means to be made active and effective only if the engineers brake valve is placed in the brake applying position and is kept in such position until the train speed has been reduced to a predetermined value.

6. In an automatic train control system, in combination, a brake control device, an energizing circuit for said device including, on one side of said device contacts controlled by a speed distance cam, and on the other side of said device a plurality of branches in multiple, one branch including a stick contact of said device, one branch including only a contact closed at low vehicle speed, and one branch a contact closed at medium vehicle speed and a front point of an acknowledging relay.

of said device a plurality of branches in multiple, one branch including a stick contact of said device, one branch including only a contact closed at low vehicle speed, and one branch a contact closed at medium vehicle speed and a front point of an acknowledging relay, said acknowledging relay having an energizing pick up circuit including contacts closed only when the engineers brake valve is in brake applying position.

8. In an automatic train control system, in combination, a brake control device, an energizing circuit for said device including, on one side of said device contacts controlled by a speed distance cam, and on the other side of said device a plurality of branches in multiple, one branch including a stick contact of said device, one branch including only a con tact closed at low vehicle speed, and one branch a contact closed at medium vehicle speed and a front point of an acknowledging relay, said acknowledging relay having an energizing pick up circuit including contacts closed only when the engineer brake valve is in brake applying position, and a stick circuit for said acknowledging relay including the last saidicontacts.

In testimony whereof I hereby affix my signature.

FRANK L. DODGSON.

Images