US1794582A

US1794582A - Train control

Info

Publication number: US1794582A
Application number: US712269A
Authority: US
Inventors: Charles S Bushnell
Original assignee: General Railway Signal Co
Current assignee: SPX Corp
Priority date: 1924-05-10
Filing date: 1924-05-10
Publication date: 1931-03-03
Anticipated expiration: 1948-03-03

Description

March 3, 1931...

c. s. BUSHNELL 1,794,582

TRAIN CONTROL Filed May 1 1924 9 Sheets-Sheet l -Ma;'ch 3, 1931. c. s. BUSHNELL 1,794,532

TRAIN CONTROL Filed May 10, 1924 951166128-31'1891; 2

(2 5 INVENTOR.

I TORNEY F IG 2 Runnjn March 3, 193 c. s. BUSHNELL TRAIN CONTROL Filed May 10, 192.4 9 Sheets-Sheet 3 IN V E TOR.

-'TTORNEY Q' Shet's-Sheet 4 N V EN TORQ March 3, 1931. 'c. s. BUSHNELL TRAIN CONTROL Filed May 10, 1924 ll-h March 3, 1931. c, s BUSHNELL 1,794,582

TRAIN CONTROL Filed May 10, 1924 9 Sheets-Sheet 5 FI G.6.1 I

FIG. 6.

I 1195 BV 188 To Eqgyb'mq Rese. om

' Z 5 @VENZOR. BY l March 3, 1931. c. s. BUSHNELL TRAIN CONTROL Fil 1 1924 9 Sheets-Sheet 6' km mo 7/. m. 27/ a d3 3. Eu 06 +3 MON 03 w mdm aw m2 3N com 3 2m EN EN mom D 1B bmd an .ieiuavmv mEsl I IN VE TORZ March 3, 1931. c, s, BUSHNELL- 1,794,582

TRAIN CONTROL Filed May 10, 1924 9 Sheets-Sheet 7 INVENTORI 6. 5.

. ATTORNEY March 3, 1931. C BUSHNELL 1,794,582

TRAIN CONTROL Filed May 10. 1924 9' Sheets-Sheet 9 Pump Governor Patented Met. 3, iesi cnannns s. BUSHNELL, or nocnnsrpn, new Y.ORK,1ASSIGNOR 'ro GENERAL RAILWAY SIGNAL COMPANY, on noonnsrnn, NEW YORK 'rnA-rn'oonrnoi.

Application filed May 10, 1924. Serial Ne. 712,259.

This invention relatesto automatic'train control system for railroads and deals more partlcularly with the problem of mamtainmg or enforcing vigilance on the part of the engineerin obeying the unfavorable indications of the trackway block signals, or cab signals if used.

According to the theory on which'the present invention may be said to be predicated, it'is desirable, in designing an automatic train control system, to maintain to the highest degree the vigilance and care of the engineer in the handling of his train which exists at present and affords a very high degree of safety. In other words, it is considered eX )edient to avoid substitution of the safety a orded by automatic devices for that now given by the engineer, making the automatic train control systemof such a character as to supplement the present vigilance and care of the engineer. It is thought that a train control system of this type would surely add to the safety of train movement, retaining all of the safety at present obtained and providing the automatic protection in addition.

Roughly speaking, the object of an automatic train control system is to stop the train or reduce its speed, if safety requires, in the event thatthe engineer fails to do so. This means that it becomes necessary to determine automatically what the safe speed for a train is at difierent points in its travel under different conditions oftraffic and-impose automatic control of the brakes if thesev safe speed limits are exceeded. As a practical proposition, on account of the variation in grades, braking power of trains, block lengths, and other practical limitations, it becomes very difficult to accurately determine automatically the safe speed limits at all points, with the result that the speed'limits which are enforced by the system of train control are more or less inaccurate in prac tice and frequently represent a compromise between conflicting factors- One simple way of enforcing vigilance of the engineer is to inflict some sort of penalty whenever the engineer fails to control his train properly and the automatic train control system has to apply the brakes. In

short, .every automatic brake application is accompanied by a penalty. In carrying out this scheme :of maintaining vigilance, it becomes necessary for the engineer tohave the speed of his train at all times below the arbitrary speed limits" automatically set up, that is, the engineer must keep below the dead-linevof automatic control in order to prior to such automatic brake application. In other words, the engineer may suppress the penalty associated with the automatic brake application by taking suitable action prior thereto. According to this invention, the engineer may suppress the penalty by manually controlling the brakes in such a fashion as to bring about a stop or reduction in speed of the train justas effectively as would be brought about by the automatic control. Theidea is that, if the engineer goes about slowing down or stopping the train himself before the automatic control takes efi'ect, he has manifested his vigilance in the best fashion and is entitled to avoid the penalty even though an automatic brake application should occuron account of the inaccuracies of the arbitrary speed limits.

This invention is specially concerned with theproblem of providing automatic devices operating "only if the engineer has brought about the proper brake control in time to justify suppression of the penalty. In this connection, it is reasoned that, inasmuch as the manual brake application re.- quired-is "assumed to be the equivalent or a substitute for the automatic brake application, such manual application should be of plaining more specifically, the theory is that the engineermay properly suppress the penalty it he places the engineers brake valve inthe service position before exceeding the critical speed limits, since such movement initiates a manual brake application as promptly sis-necessary for safety.

; With the ordinary type or" air-brake equipinent, if the engineer Were required to keep this enginee'rs brake valve in the service position for a considerable time in order to suppress the penalty, there would be an unnecessary over-reduction in the brake pipe pressure and Waste of air. Hence, it is desirable to provide additional means permitting the engineer to lap his brake valve, provided he has kept this valve in the service position long enough to assure an adequate brake application. One type of such means, herein disclosed, consists of a time measuring device which permits lapping of the engineers brake valve if it has been held in the service position for a time (about six or seven seconds) sulficient to reduce the equalizing reservoir pressure and assure an adequate application of the brakes. Another type of such means operates upon the drop in pressure in the equalizing reservoir and permits lapping of the engineers brake valve after the equalizing reservoir pressure has been reduced the desired amount.

Since the penalty under consideration is associated with the automatic brake application, this penalty may be suppressed by preventing operation of the devices causing such brake application, inasmuch as the penalty exists only if there is an automatic brake application, and a. suppression of operation of such automatic brake applying mechanism carries with it the suppression of the penalty. On the other hand, since it is the penalty which it is desired primarily to suppress, the system may be organized on the basis of suppression ot penalty only, allowing the automatic brake applying mechanism to operate each time the critical speed limits are exceeded, irrespective of What action may have been taken by the engineer.

' The latter arrangement has the advantage that the automatic brake applying mechanism is kept in good operating condition by frequent use; whereas in the former arrangement, this mechanism, except for occasional tests, never operates except in thos rare cases of automatically controlling the air-brakes of trains for train control purposes has reference to limiting the amount of brake pipe reduction occurring upon an automatic brake application. Those familiar with the airbrake art will readily appreciate that the brakes are applied to the fullest extent after a certain limited reduction in brake pipe pressurehas been made, and further reduction in brake pipe pressure is merely a Waste of air which must be replaced before the system has been re-charge'd to normal. Now, where there is a suppression of penalty by a timely manual brake application, it is especially important that the brake pipe reduction occasioned by the respective manual and automatic control should be correlated so as to avoid an over-reduction; and more particularly it is desirable that the automatic mechanism should cut off as soon as the desired reduction has been made, whether due in Whole or in part to manual control, or to automatic control.

Another aspect of the problem of automatic braking refers to what is generally known as split application. In handling the brakes on a tonnage train, it is frequently expedient to make the application of the brakes by two or more separated reductions in brake pipe pressure so as to govern the slack and avoid shocks between cars. Conse quently, the penalty suppressing means should preferably permit the engineer to make split applications; and this requirement modifies in some particulars the character of the devices determining that an adequate reduction in brake pipe pressure has been made. lVhile the automatic brake applying mechanism of this invention may be organized to give automatic split applications, it is considered that the suppression of penalty characterizing the invention makes such automatic split applications of less importance, for the reason that the engineer may split his manual applications and get the slack under control before exceeding the critical speed limits.

The principal and primary objects of this invention are to provide various forms of devices, and organizations and combinations of devices to meet these various requirements and problems briefly outlined above. The fundamental principles of the invention have been worked out in several forms, and have also been applied to different types of speed control systems. The particular disclosure, however, is more illustrative of the character of means constituting the present invention than a comprehensive showing of all ways in which the invention may be practiced; and it should be understood that the invention is not limited to any particular structure or organization herein disclosed, but is susceptible of adaptation and medication to meet the needs of any particular situation.

Various specific objects, purposes, advan tages, and characteristic features of the inventionwith appear as the description progrosses." i

. In describing the invention in detail reference will be had to the accompanying draw ings in which:

1 shows the trackway equipment of a train control system of the intermittent timedistance interval type having the present invention applied thereto, and also illustrates the permissive speed and braking character istics for one particular block;

g. 2 illus rates the usual engineer s brake valve having a valve actuator applied thereto, whereby an unpreventable brake applica tion maybe made automatically, and further shows means for suppressing a penalty if an automatic brake application is anticipatedby a manual brake application;

Fig. 3 shows the car-carried circuit arrangement of a train control system ofthe time-distance interval type of Fig.1, the apparatus shown in Fig. 2 having been shown conventionally V V Fig. 4- illustrates the car-carried and trackway apparatus of a train control system of the continuous inductive type having the present invention applied thereto;

Fig. 5 illustrates a penalty suppressing means in which a miniature brake cylinder having a pressure therein corresponding to that existing in the main brake cylinders i employed so as to determine when an adequat brake application has been made. i

F Gillustrates a modified arrangemen for determining when an adequate brake application has been made.

Figs. 7 and 8 illustrate a still diilerent modified arrangement for suppressing the penalty, in which predetermined reduction from normal in the equalizing reservoir pressure suppresses the penalty; and also serves to permit the engineer to return thelrotary valve to'the lap position after an automatic brake application has been ei'l'ected, to prevent excessive venting by such automatic application;

Fig. 9 shows the trackway equipment and a portion. of the car-carried equipment of a two-position continuous inductive train control system, and graphically illustrates how the speed of the train may be reduced in a cantion block for different entrance speeds without the infliction of a penalty; I

Fig. 10 shows the remainder'or" the earcarried equipment shown in Fig. 9

Fig. 11 illustrates a modified form of pe alty suppressing means similar to that shown in Fig. 10; V

ll shows a penalty suppressing means like that shown iii-Fig. 11 but having a modified form of contact associated therewith which closes a circuit when a predetermined degree of brake application has been initiated; and

Fig. 12 illustrates a train control system similar to that shown in Fig. l in which the penalty alone is suppressed without suppressing automatic operation of the brake. control device, and in which a separate bra re applying device is used which l mits the degree of brake application regardless of a concurring or preceding manual brake application.

In order to fully disclose the manner in which the invention may be applied to various types of train control systems, the invention has been illustrated in connection with two entirelydiiierent systems, namely (1) the intermittent inductive time-distance interval speed control type; and the continuous inductive speed control type. The first portion of the specification is directed to the intermittent type and the latter part to the continuous inductive type.

Intermittent system Track way apparatue.lteferring particularly to Fig. 1, there has been shown trackway apparatus for an. intermittent time-distance interval type train control system applied to a portion of automatic signal territory. The track rails 1 are divided by. insulated joints 2 into blocks, the block I and the adjacent ends of two other blocks H J being shown. Since the various blocks are the same, like parts of each block are designated by like reference characters with distinctive exponents. Although the train control system in question may be used in connection with traekway signals of any type, either color light, position light or semaphore signals, semaphore signals Z have been shown conventionally without illustrating their well-known control devices and circuits.

The exit end of each block is provided with a suitable source of trackway energy, illustrated as a battery 8; and the entrance end is provided with a track relay 4:. On the right hand side or the track, the direction of trafiic being fromyleft to right as indicated by the arrow, are pairs of trackway elements T for inductively transmitting control influences to suitable car-carried apparatus under cantion traffic conditions of the block. Since the car-carried apparatus, as will appear hereinafter, responds only to two successive control influences in less than a predete mined time, only one element T of each pair need be made inactive under clear trafiic cond ions, the other element always being active. Each of these track elements T (see Fi 3) comprises a U-shaped core 5 preferably constructed of a high grade of laminated magnetic material terminating in enlarged pole pieces 6. The controllable track element is also provided with a coil 7 on its core 5 which is normally closed in a circuit of low resistance through the front contact 8 of a line relay 9. Referring to the block 1, these variousline relays 9 of each'blocl: are connected in me ple across line wires whicl under clear tranc conditions, are energized by the battery 10 through the front contact 11 of the track relay P.

In Fig. 1 there has been gran ically illustrated by vertical and horizontal dotted lines the speed limits set up at the three control points at which the pairs of track elements T are located. In this diagram the solid line 12 represents the speed-distance brake application curve of a certain train, the vertical distances representing miles per hour, and tie horizontal distances representing points in the block in question. The horizontal dotted line 13 represents the speed limit enforced by the pair elements T, the dotted line i l the speed enforced by elements T, and the dotted line 15 represents the speed setup by the elements T. It is thus noted that the train may run at speeds at various points in the blocks as indicated by the dotted line 16 without exceeding the permissive speed limits. As more clearly pointed out hereinafter, the train may travel at speeds as indicated by the dot-and-dash line 17 under caution traflic conditions if the engineer has anticipated the automatic brake application by effecting an adequate brake application or initiating such a brake application.

Oar-carried apparatus EZectm-gmcmnatic valve EPV.As an au tomatic brake applying dev1ce, an electropneumatic valve EPV has been shown in Fi 2 which may be used to vent the brake pipe directly, if its wlndlng 20 1s deenergized, may

actuate a suitable brake valve actuator, such gized, the valve 23 being maintained closed by a compression spring 24, the weight of the

valves

21 and 23, the armature 22 and the valve stem 25.

Brake cal 0e actuato1.1n Fig. 2 there has been illustrated the usual engineers brake valve BY, including the usual rotary valve provided with standard ports, from which t ie valve cap has been removed and for which a special cap 28 has been substituted. This cap 28 is provided with

opposed cylinders

29 and 30 in'which move pistons 31 and 32 connected to ether by a rack 33.

Extending up from the usual rotary valve (not shown) is a valve stem 3d on which is pivotally mounted a pinion having two upwardly extending pins which are adapted to engage the actuator plate AP. Movement o the rack 33 in one direction or the other otates the pinion 35 and actuator plate AP in the corresponding direction; Directly above the actuator plate AP is a valve plate VP, which is directly connected to the valve stem 34 in any suitable manner, so that rotation of this plate VP rotates the rotary valve. ilirectly above the valve plate VP is a handle nlate HP, which is directly connected to the "leeve 36 to which is keyed the usual enineers brake valve handle 3?.

Under normal operating conditions, when the winding 20 of the'valve EPV is energized, main reservoir pressure is present in both of the

cylinders

29 and 30, and the rack 33 is moved to the left hand extreme position, because the cylinder 29 is larger than the cylinder 30. The handle 37 is directly coupled to the valve plate VP by the latch 38 held in position by a coil spring 19. Under such normal conditions, the handle 37, which is shown in the normal running position, may be moved to the release position, carrying with it the valve plate VP and handle plate HP held together by the latch 38, so that the engineer may apply the brakes or release them without interference by the actuator mechanism, the lap, service and emergency positions of the handle not having been specifically indicated.

Nhen an automatic brake application is initiated as a result of deenergization of the valve EPV, causing the rack 33 to move toward the right because 'the cylinder 29 is vented to atmosphere, the actuator plate AP moves in a counter-clockwise direction; and during the first portion of its movement (this being an idle movement), the cam 39 raises the latch 38 and thereby unlatches the handle plate HP from the valve plate VP. Further movement of the rack from the left to the right moves the valve to the service brake applying position by reason of engagement of the upstanding lug 26 on the actuator plate AP with the extending arm 27 of the valve plate AP. The engineer cannot hold as, so to speak, or prevent an automatic brake applicationby moving his handle 37 to the release position, because the engineers valve is unlatched from the valve plate and rotary valve, as far as movement in the clockwise direction of the handle is concerned; but the service position, by the engagement of lug 26 with the extending arm 2?, but will not again move the valve to therunning position when the device EPV is again energized, because there is no mechanical connection between the actuator plate'AP and the valve plate VP for movement'o'f the actuator plate in the clockwise direction. This'is desirable because it requires a positive act by the engineer each time the brakes are released.

Penalty and suppressing mca-ns.ln the particular form of the invention shown, the penalty imposed upon the engineerfor negligence or neglect to take the appropriate action consists in requiring the train to be brought to a stop before the brakes can be released and the train proceed at speed. This is accomplishedby providing a suitable reset switch RS, which is so located on the locomotive that itis accessible only by one standing on the ground, and which is so protected that it cannot be held closed. Consequently, when the engineer fails to take the appropriate action in manifestation of his vigilance, and the automatic apparatus on the locomotive assumes afcertain condition, the brakes cannot be released and the train proceed, until it has been brought to a stop and someone has operated the reset switch from the ground.

The embodiment of the invention shown utilizes electrical control of devices primarily, and hence, the penalty inflicting means,together with the means for suppressmg such penalty, involvethe opening and closing of contacts. As apart of the penalty suppressing means, the engineers brake valve I is'provided'withcontacts which are opened and closed in certain positions of the. brake valve. In the form shown in Fig. 2, on the sleeve 36, to which the engineers brake valve handleB? is fixed, is a collar 420i insulating materialto which are fastened contact strips or segments 43, {la and l5;'and adjacent to these segments are palrs of contact fingers" 46, 47'and48, which are bridged by said segments in different positions of the valve handle. The contact finger 43 is of such length that it bridges and electrically con-- nects its cooperating pair of fingers 46 if the engineers valve handle is in the l -P. the service, or the emergencyposition. Similarly,itl16 contacts. a a bridgetheir respective pairs 'ofcontact' fingers withthe engineers valve handle in either the service or the emergency'position.

For reasons outlined hereinbetore, it is de sirable, in connection with the suppression of the penalty, tohave automatic, mammasponding if, and only. if, the engineer'jhas made the desired manual control or air-brake system suflicient'to assureabralre application of the required intensityQ In this particular arrangement, under consideration, it is assumed that theengineerhas exercised therequired manual control-when he has madea certain predetermined reduction in the pressure in'the equalizing reservoir of the airbra re system. The operation of the usual type or" air-brakes'ysteni is well-known, and

the function of the equalizing reservoir pressure is familiarto those skilled in the art, so 7 i it will be sufficient to point out theta reduetion in equalizing reservoir pressure is automatically followed by a reduction-in brake pipe pressure to correspond, and that so far as the manual control of the air-brake system is concerned,tl1is has been fully accomplished as soon as the equalizing reservoir pressure has been reduced the desired amount. a

Forthe purposes of this disclosure it has been assumed that the speed restrictions automatically imposed by the train control system will be based upona full service brake appli= cation, corresponding to full equalization of pressure between the auxiliary reservoir and brake cylinder of each car. .Roughly spealn ing, such a full service application represents about 20 pounds reduction in the brake pipe pressure, and correspondingly in the equalizing reservoir pressure. "With the typical equipment it takes about 6 or 7 seconds to make 'a' 20 pound red c ion in equalizing reservoir pressure. Putting it another way, if theengineers brake valve ishe-ld in the service position for 6 or 7 seconds, the pres-, sure in theequal zing reservo1r will drop in this time sufiicient toproduce substantially a full service application. In short, if we measure the. time that the engineers brake hasabeen'inthe service position, without any intervening release orrecharge, is equal to 6 or? seconds.

. Referring now tothe specific means shown in Fig. 2, a cylinder 50 has a movable piston 51 therein, which is urged in one direction (to the right, as shown) by a compression coil spring 5.2. Ibis pist n 51 provided with a packing or rings, in accordance with approved practice, so as to prevent leakage by it; and to insure a quick or snap movement, this piston has ridges on its faces cooperating with gaskets in the extreme position of the piston.- Insulated contact disks or

members

53 and 54 are fixed to the rod or plunger of the piston 51, and engage pairs of fixed con tacts, shown conventionally as'arrows, when the piston has shiftedto its extreme left hand position. V

The right hand side of the piston 51 is in communication with a small capacity reser voir 55. The pressure in this reservoir 55 is controlled by two electro-pneumatic valves DV and RV of suitable construction, which in turn, are controlled electrically in accordance with the position of the engineers brake valve handle. The valve DV, if deenergized, connects the reservoir 55 to atmosphere, but if energized closes its exhaust. The winding of this valve DV has its energizing circuit through the contacts l3 l6 of the engineers valve, so that said valve DV is energized if the engineers valve is in the lap, service, oremergency positions, but is deenergized for the running or release positions. The other valve RV, if energized, connects a suitable source of pressure, in this instance the brake pipe, to the reservoir 55 through an adjustable restricted orifice 56, so that the flow of pressure into said reservoir varies in accordance with time. If the valve RV is deenergized, such supply of pressure is cut olf. This valve RV is energized by a circuit through the contacts l5l8 closed with the engineers brake valve in the service or the emergency positions.

With the engineers brake valve in the normal running position, the parts are in the position shown in Fig. 2, both of the valves DV and RV being deenergized, the reservoir 55 at atmospheric pressure, and the piston 51 7 held in the right hand position by its spring.

When the engineer moves his brake valve to the service position, both of the valves DV and RV are energized, the valve DV closing and cutting off the exhaustfrom the cylinder 55, and thevalve RV opening to admit pressure at a slow rateto this reservoir. The size of the reservoir 55 and the area of the restricted orifice 56 ar'e selected so that after the expirationof the desired time (assumed to be 6 or 7 seconds), the pressure inthis reservoir builds up to the point where, acting on. the exposed right hand face of the piston 51, it overcomes the tension of the spring 52 and moves the piston toward the left. As soon as the'piston5l starts to move to the left, it breaks the gasket seal and exposes a larger area to the pressure in the reservoir, whereupon the piston shifts quickly to its extreme left hand position, since the increased area exposed to pressure more than compensates for theincreased tension of the spring due to contraction. \Vhen the piston 51 reaches its extreme left hand position, the

contact members

53 and 54 engagetheir cooperating pairs of contacts. During the time that the engineers hrakevalve was in the service position to bring about this result, the equalizing reservoir of the regular air-brake equipment was, of course, being vented; and before the expiration of the 6 or 7 seconds, it is certain that the prcssure'in this equalizing reservoir has been exhausted through the preliminary exhaust port in the engineers brake valve to bring about the desired reduction. this time, the engineer is supposed to lap his valve, thereby arresting further venting of the equalizing reservoir pressure and avoiding over-reduction in brake pipe pressure and useless waste of air. lVhen the engineer moves his valve to the lap position, the valve RV is deene'rgized on account of the opening of the contacts 45 l8, while the valve DV is kept energized and maintains the pressure in the reservoir 55 to hold piston ,51 in its left hand position and keep contact disks 5354 in their circuit closing position.

If the engineer should attempt to release the brakes by moving his valve to the running or release position, the valve DV is deenergized and opens to exhaust the pressure in the reservoir 55 immediately, whereupon contact disks 5354.- at once assume the open position, to cause the actuator to again operate the brake valve to the service position, and enforce speed restrictions as more particularly pointed out hereinafter. While the engineer cannot release the brakes, he may split the reduction into two or more stages, moving the valve back and forth between the service and lap positions. In the service position, the valve RV is energized and pressure builds up in reservoir 55 in accordance with the lapse of time; and solong as the engineer does not go beyond the lan position to the running or release position, the valve DV is maintained energized to hold what pressure may have been built up in the reservoir 55. It will be evident that the piston 5l does not shift until the accumulated or total timethat theengineers valve has been in the service position equalsfi or 7 seconds. By virtue of this arrangement, the engineer may make a partial application of the brakes to adjust the slack before exceeding the critical speed limits, and is not necessarily required to make his man ,ual application all in one stage. After the critical speed limits are exceeded, however, the engineer must maintain his brake valve in the service position until the necessary reduction in equalizing reservoir. pressure has been made. In. other words, the engineer may split his applications'asmuch as he pleases before crossin the dead-line of permissible speed limits, but after crossing this line, he must keep his brake valve in the service position until the proper manual brake application has been set up,it being obvious that this is necessary to be sure of safety, inasmuch as the speed-limits are based upon a continuous one-stage reduction, and to assure undermost unfavorable circumstances the equivalent manual application, all reductions after crossing the dead-line should be made in one stage. i

Influence receiving car element. The ref: erence character L designates a car-carried element comprising an inverted til-shaped core of laminated magnetic material terminating in enlarged pole pieces. The legs of this core '59 are provided with a primary coil P and a secondary coil B respectively.

This car element L is preferably supported:

from the truck of the railway vehicleina manner so as to cooperate with the track ele ments T (see Fig. 1) through a'small intervening air gap of from 1 to 2 inches, the

middle of thisair gap being,say, 3 to 3% inches above the top of the track rails.

' Relaya-The car-carried apparatusof the.

intermittent time-distance interval system shown in Fig. 3 includes relays GB, RB, BR

and PR. -The first three of these relays are preferably sensitive and immune to jars and vibrations, this being accomplished by making their arinaturesvery light and well-balanced and by supporting. them about a vertical axis so that swinging and jarring of the railway vehicle will not tend to operate such armatures. The penalty relay PR need not be from thetrackwayapparatus in less than a certain intervalof time, it is necessary to have a reliable time elementdevice on the vehicle which measures the time between successively'rece ved controlinfluences. In the system shown in Fig. 3 this time element (18-.

vice is one that functions on the principle of accelerationor deceleration of a mass similar to timing mechanism in watches. 7

This device TE hasbeen shown conventionally and comprises a shaft to which is fastened a balance wheel '61. This balance wheel 61 is held in its normal'position by a time starting magnet TS acting on an arma ture 62 fastened to the non-magnetic balance] This shaft 60 and the'balance wheel 61; wheel 61 are biased so as-to assume an inter- ,mediate position substantially 90 toward the right of its normal position, in which it" is: shown, by aspiral spring 62, and is pro vided with contacts 63'and-6i adapted to con tact withstationary contacts 65 and 66 re-. spectively during different parts ofthe full oscillation of the wheel. If the time starting magnet TS is momentarily deenergized, the balance wheel 61 will be swung in the clock wisedircction, and passes its biased position at substantially 90 making a swing of almost 180, after which it will swing back almost to its initial position, and if the time starting magnet TS is again'energized will again be attracted to its normal position. Speed responsz'oc desicc.-One element of the car-carried apparatus is speed responsive device which reflects the speed at which the vehicle is traveling at any point along the trackway; and in the'particular arrange ment shown this device G is of the centrifugal type, including a shaft 69 driven from the wheels of the vehicle in any desired manner. @n this shaft 69 is pinned a sleeve 70 and is slideably supported a collar 71 having a contact disk 72'connected thereto but insulated therefrom. To the sleeve 70 and the collar 71 are pivotally secured links 73 which are pivotally connected at tlieir'free ends to balls 74, a compressioncoil spring 75 surrounding the shaft 69 tending to separate this sleeve and collar as far as possible. Rotation of the shaft69 causes the fly balls 7% to sep arate and pull the collar 71 down against the tension of the spring 5 so that the contact disk 72 assumes a position depending on the j speed of theshaft 69 and closes a circuit when the speed of thetrain is less than a certain value, assumed to be about 20 miles per hour.

Operat'ion of intermittent eg stem Figs. 1 to 3 arrangement shown, the primary coil P- of the car element L is energized by the following circuit :'be ginning at the terminal B, wire;

77, primary coil P, wires78 and 79, neutra point NP, through discharge -resistance '80,- I

back to common return wirerC. The fiowof current through ,lZlHS circuit causes the neu tral point NP toassume a certain intermediate potential between that of he terminals Under norinal conditions of the apparatus shown, the control relay CR and secondary coil S are connected in series between the terminal B and the neutral pointNPby a'cir-" cuit which may be traced as follows:eter- I minal B, wire 81, front contact 82 of the con-' trol' relay CR, wires .83- andfSt, winding of vlliththis control relay CR energized,.the

following circuit for the repeater relay RR may be traced:beginning at-the terminal 13 of the battery, wire 81, front contact}87

wires

88 and 89, winding of the repeater -rc-- the repeater relay RR, wire 93, back to comk mon return wire C.

Another circuit is energized by the. control relay CR when energized which includes the same front contact 87 and which may be traced as follows :beginning at the terminal B, wire 81, front contact 87-,

wires

88 and 97, lower winding of the brake control relay BR, wire 98, front contact 99 of the brake control relay BR, and wire 100 back to common return wire C. r

The circuit just traced is a stick circuit for the lower winding of the brake control relay BE. A stick circuit for the upper winding of this brake'control relay BB is closed when the time element device TE is in its normal position and may be traced as follows :beginning,at the terminal B, wire 101, contacts 6365 of the time element device, wire 102, upper winding of the brake con trol relay BR,

wires

103 and 10 1, front con tact 105 of the brake control relay BR, and wire 100, back to common return wire C.

With the brake control relay BR energized, the electro-pneumatic brake control device EPV is energized by a partial circuit starting from the neutral point NP as follows wire 106, front contact 107,

wires

108 and 109, winding 20 of the EPV, wire 110, reset push button switch 111 only accessible from the ground, wire 112, back to common return wire C. It is of course noted that the current flowing in this partial circuit also flows through the primary coil P, the complete circuit beginning at the terminal B of coil P and ending at C of the reset switch RS.

Vith these various circuits closed as de scribed, suificientcurrent will flow in the primary winding P to the neutral. point NP to set up a large magneto-motive-torce 1n the car-element L establlshing a certain amount of flux, a large part of which, it is believed,

passes through leakage paths and a certain party of which. passes through the secondary coil S. i

It should be noted at this time that the: control relay GR is connected in series wi h of depreciation of the source of energy, and

the like, causes a similar change in the potential across the secondary coil S. In other words, weakening of the primary field causes lowering of the potential across the relay CR, so that asmaller impulse will cause dropping 01' this relay. The discharge resistance serves two purposes, namely :permits the flow of current in the primary coil P when the device EPV is deenergized, and also acts as a discharge resistance to prevent arcing at the relay contact when the circuit for the device EPV is opened.

Caution c0ndit0nsspeeci not excessive. Let us assume that the blockJ is occupied by a train, thereby depriving the track relay 41 of energy and in turn deenergizing the line relays 9 so that the coils 7 on the track elements T, T and T are open circuited, making these track elements active.

Let us further assume that a train, equipped with the car apparatus shown in Figs. 2 and 3, is moving in the block I and passes the first pair of track elements '1 at a speed less than that shown by-the dotted line 15. When the car element L passes over the first track element '1, bridging of this element L by the core 5 causes a sudden increase of flux in the secondary coil S. This increase of nun, it is believed, is largely due. to a diversion of flux from the leakage paths, and to a certain extent is due to therincrease in the total flux passing through the primary coil P. As the car element L recedes from the track element T, the flux passing through the secondary coil S again reduces to normal. This sudden increase and decrease of the flux passing through or linking the secondary coil induces a voltage in this coil corresponding to a single cycle of alternating current electromotive-force. The, coil S is preferably so connected in the circuit with the control relay CR thatthe first wave of this single cycle of voltage is in a direction to oppose the voltage of the battery, thus decreasing the current through the control relay CR enough to cause its armature to be retracted by its biasing spring (not shown) to the dotted line position. With the control relay CR once deenergized, it remains in its deenergized position until restored by some other means, because its stick circuit has been broken.

With the control relay deenergized, the stick circuit for the repeater relay ER is broken, thereby deenergizing this relay RR and in turn the time starting magnet TS of the time element device TE, thus starting the time element device on its cycle of operation in a clockwise direction. Deenergization of the control relay GB at this time also interrupts one of the stick circuits (including the lower winding) of the brake control relay BB; but this relay, however, remains in its energized position by reason of its other stick circuit including contact 6365 of the time element device. As soon as the repeater relay RB assumes its deenergized position, a pickup circuit for the control relay GR is 00111 pleted as follows :,beginning at the terminal 13, wire 113, back contacts 114 of the"repeater relay RR,

wires

115 and 84, winding" of the control relay GR, wire 85, secondary coil S, wires 86 and 79, back to the neutral point NP. The completion of this pick-up circuit again picks up the control relay CR which is then maintained up by its stick 'cir cuit heretofore traced. The restorationof the relay CR were deenergized while the time element IdeviceTE isperforming its cycle vof operation, and the 'cont'acts63 and are broken, the st ck circuit for the lower winding ofthe brake control relay BR would also be broken at this time, and the brake control relay 1BR would assume its deenergized position. Since, however, it has been assumed that the speed ofthe train is less than that indicated by the dotted line 15, the time element device TE will have'completed its cycle of operation and will again be in the normal positionfbefore the car element L traverses the second track element of the first pair, so that passageof the car element L by the second element of the pair causes the same cycle of operationto take, place without deenergizing the brake control relay BR,

The same operationoccurs at the second pairof track elements T provided the speed of the train is below the limiting speed indicated by the dotted-line 14, this speed limit being lower because the track elements of this" pair are spaced closer together. At the pair,

of track elements T the speed of the train must be still lower to avoid automatic con-- trol. A speed distance curve representing possible or typical, performance which the exceeding these speed limits. Under this asspeed limit for this pair, represented by the dotted line 15, and the engineers brake Valve is in the running position. As the train passes the first track element of the pair =T, therelays GR and BB drop their armatures and are then restored by pick-up circuits including contacts 114 and 66 the same as above described, and the balance wheel of the time 7 element device is set'intomotion. Since the speed is assumed to be too high, the train reaches the second track element of the pair T before the balance wheel ofthe time element device has returned to its initial positionto close contacts 63-65.. Consequently, I

whenfthe relays CR and RR drop their armatures the second time at the second track element of the pair, both of the stick circuits for the relay BR are broken, one at the front contact 87' of the relay CR, and the' otherat the contacts 6365' of the balance, wheel. Thearmature of the relay BR, therefore, movesat once to its retracted position" opening valve 21. Pressure is then exhausted from behind the, large piston 31, andthe main reservolr pressure constantly acting on',

the small piston 32 shiftsthe rack 33 toward the right; As previously "explained, this movement ofthe rack 33, driving the actuator plate AP, first releases the latch 38 from engagementwith thearm 40, and then by rea-' son of contact .of'the lug 26 with the arm 27 ofthe valve plate "VP, drives the engineers'rotary valve, free from the handle'37, to the serviceposition. The engineer cannot prevent this movement, since his handle is unlatched from the rotary valve for movement towards'tthe release position; but the engineer can at any time move the rotary valve still further to the emergency position.

Under the conditions assumed the engineer has not been vigilant and hence the penalty" should beenforced. This is accomplished by requiringthe train to be stoppedand the reset switch RS operated, in order to permit reenergization of the relay BR. It may be explainedhere that other forms of penalty are, of course, applicable to the arrangement shown in'Fig. 3. [For instance, instead of establishingthe pick-up circuit for reenergizing thefrelay BR by manual manipulation of the resetswitch RS, this may be done by closure of cont-acts of :the speed responsive device G,Jwhich are closed only after the speed of the train has been reduced-to a very low speed, such as two'miles per hour, meaning that the trainhas been brought substantially to a stop. Such a modificationis indicated in other forms of the invention here- I ina fter explained and its applicability to this particular embodiment is too obvious to require specific illustration.

When the engineerpushes this push button 111, the time element deviceTE in the meantime having returned to its normal position, a pickup circuitfor the brake control relay BB is established which may be traced as .fol-

lows :wi re 101, contacts 6365 of the time element deviceTE, wire102, upper windingand the engineer may release the brakes by moving his handle to the service position, latching the handle plate HP tothe valve plate VP andthen returning the. handle to the running or release position.

The enginer has been penalized by being required to come to a fullv stop .andget out to operate the reset switch RS, which is only accessible from the ground;v and thisis proper because he was not vigilant and did not either reduce speed or apply the brakesv manually. Further, it should be noted that the. reset switch RScannot be maliciously tied down, so as to avoid the penalty, because the push button 111 has to bein its upper position before the device EP V maybe energized and if,

tied down, the train could not move.

Caution condition-speed excessive-pen:

al tg suppresse,cl.Letus assume thatthe train in question is entering the block I under caution trailic conditions at a" speed ofabout 65 miles per hour, asindicated by the dot-anddash line 17 at the entrance to the block I. Let us further assume that they engineer: is alert, and upon entering the block I, observes the caution signal, and realizing that the speed of his train ishigher than the safe or restricted speed limit provided by the train control system, initiates a manual brake application to reduce speed, and accomplishes this initiation by putting his brake Valve in the service position before the train reaches the pair of track elements T.

As soon as the engineer puts his brake valve in the service position, a pick-up circuit for the penalty relay PR is established and may beconveniently traced as follows beginning at the neutral point NP, Wire 106, front contact 117 of the relay BR, Wires 118 and 119, relay PB, wires 120 and 121, contacts 47 44 on the engineers brake valve, and Wire 122 to the common return Wire 0.

traced includes the front contact 117 V of the gene relay BR; and consequently. the engineer:

must-act before the relay BRis deenergized, as aboveexplained, by the passage of the train over a pair of track elements at excessive speed. Once the penalty relay PR is energized, it is maintained energized by a stick onds), the piston 51 (see Fig. 2) shifts and moves the

contact'dis'ks

53 and 54 into engagement with their cooperating contacts, where upon the engineer may move his valve to the lap position, but no further, and the penalty relay-be maintained energized, the electrical connection to the common return

wire C througlrwires

127 and 128 being substituted for that through

wires

121 and 122.

W'ith respect to the automatic operation just described, it is important to note that the engineer must act before exceeding the speed limit in order to have the penalty relay energized before the relay BR is de-energized and thereby'avoid the penalty which is inflicted with this relayPR de-energized, at the time the speed limit is exceeded.

Conseqnentl the engineer must'be alert and vig- 7 ilant in watching out for the block signals occurs on the train, if he is to avoid the penalty. This means that the engineer is obliged to keep a good watch along the track and will be more likely to observe obstructions on the track than if his attention is diverted to signaling devices in the cab. If the engineer is vigilant and manually applies the brakes himself in obedience to the caution signal and excessive speed, then the train wi l be safely stopped, even if the train control equipment should be for-any reason out of order. Another point of interest is that it is not necessary, in order to forestall the penalty, thatethe engineer should have in effect a full service application before exceeding the .critical'speed limit, but is merely required to have his brake valve in the service position; Safety is assured by this arrangement because it takes about as much time for the automatic device to bring about a brake application as it does by the engineers brake a e;-

Assuming that the engineer has been vigilant and the penalty relay PR- has been ener- V V gized, when the train passes the pair of track It will be observed that the circuit just,

vigilance and anticipatory manual brake application ofthe engineer does not avoid the automatic brake control, allot the automatic brake setting devices operating the ergized, and the valve actuator (Fig. 2) operates automatically; but since the engineers valve has already been placed manuallyin the service position, the operation of the valve actuator is merely an idle movement, unlatching the engineers brake valve handle 37 from I the rotary valve itself; As soon as the en-.

gineers brake valve has been in the service position for -6 or ,Tseconds, the contacts close; and since the penalty relay PR is en ergized, the electro-pneumatic valve EPV is reenergized by a circuit as fOllOYVSPTCOlH mencing atthe neutralrpoint "NP, Wire'l23,

front contact 129 of relay Plh vvire 130, contacts 53,

Wires

131 and 10$),Ivalve EPV,vvii'e 110, push button .111 and wire 112 to the common return W re. T he reenergization'ot the valve EPV restores the parts of the brake valve actuator to normal position, and the engineer may now-lap his valve and avoid further reduct on in the equalizing reservoir pressure and the resultant reduction in brake v pipe pressure. If it should happen that the engineer has had his brake valve in the

service position

6 or 7 seconds before passing the pair of track devices T at excessive speed, then the contacts 53 are, closed, and the valve j EPV Wouldnot be deenergized or the actuator operatedwhen thebralrecontrol relay BR is deener gized, In other Words, after a predeterminedreduction in equalizing reser-' voir pressure has been made, turther reduction by automatic operation is prevented.

The engineer cannot defeat, the objects of the invention, and i fhe should attempt to release the brakes after avoiding the penalty and before automatic restoration of the train control equipment, then assoon as the engineerplaces his brake valve in the release or running position, thevalve DV (Fig. 2) opens, theJreservoir pressure 55 is quickly vented, and the

contacts

53 and 54; open, and

V the electro-pneumatic' valve EPV is immediately deenergized. The engineers brake valve actuator is accordingly automatically operated at.once,-taking the control of the brake valve out of the hands of the engineer v and automatically moving it to the service position. lhe opening of the contacts 54, with the brake valve in the running or release position, interrupts the stick circuit for the relay'PR and causesvits' armature to assume the retracted position; and since the relay BB is assumed to. be deenergized at this time, the relay PR can not be energized again by putting the engineers brake valve in the service position. Consequently, the penalty is inflicted, and also the valve EPV remains deenergized irrespective of the In the particular arrangement shown, the pick up circuit for thevalve EPV includes the frontcontact 129 of the penalty relay PR, so that this valve can be energized aftera predetermined reduction has been made only in the event that the engineer is vigilant. This arrangement is adopted onthe theory that such over-reduction as might occur would serve'as an additional-penalty, requiring insoine instances extra-time to pump up the brake. pipe pressurei Some users, however, may consider that such oVer'-- reduction should be avoided at all times, and this can readilybe done by omitting the front contact-129-ot the relayPR and connecting the wire130 directly to the neutral point NP, such a change being so obvious as not to require illustration. With such a modified arrangement, the electro-pneumatic val've EPV will be reenergized for each automatic operation after a predeterminedreduction has been madein equalizing reservoir pres sure, corresponding to a time of 6 or 7 seconds,

whether the engineer has been vigilant-or not. Such re-energization of the'valve EPV' In the form of the invention just described,

it Will be noted that there can no objectionable action occuronaccount ofthe simultaneous occurrences of the automatic and the vmanual brake control, because the same dc vice, namely the engineers brake valve, is

used for both the automatic and the manual brake application.

7 Release after automatic operation-eagncer oz'gz'Zcmt.Assuming that the engineer has been vigilant, as above described, and also that speed of the train is above the arbitrary speed limits imposed by the system. The train leaves the first pair of track elements T with the relay BR deenergized and the penalty relay PR energized. I The engineers brake valve may be still in the service position, or may have been moved back to the lap position, in case there has been time enough to effect a predetermined reduction. Vith the car equipment .in this condition, there are three different contingencies under which this equipment may be restored to the normal condition to permit release of the brakes, namely:(a) the speed of the train is reduced below the permissive speed limits at the next.