US1742188A - Train-control system - Google Patents

Description

Jano7,1930. HAD 1,742,188

TRAIN CONTROL SYSTEM Filed Jan. 5, 1925 3 Sheets-Sheet 3 I l l I I l I l I I I BY M A; ATTORNEY Jan. .7, 1930 I AD M 1,742,188

TRAIN CONTROL SYSTEM Fild Jan. 5, 1925 E-Sheets-Sheet 2 M ATTORNEY 1m "1 Jmmo a; 9 MUM, A, H. ADAMS TRAIN CONTROL SYSTEM Filed Jan. 5, 1923 5 Sheets-Sheet Can: Gan/77701. 1.0?

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from the spirit of my invention. Neverthe less, such non-abrupt forms would re uire, in order to operate a. uick polarized re oy, at larger emplificetion between the inductors on the locomotive and the relny than does In preferred abru tly changed wave form. great many suitable wave forme can be devised. l have shown in the drawings only two, illustrative of the forms hnvm the abrupt chnnge J1 prefer. One is e gra uelly built up current flow in the track, with no sudden en interruption as is possible. The gradual current rise will induce in the receivor on the locomotive at relatively long con tinued hut very Wool: current, too Week to overcome the starting: rceistnnce mechenicel and magnetic -o'l the polarized relay. @n the other hood the ehru t interruption will generate o hriei reletive y strong impulse in the receiver. As is described formally he low, Fig. Q of the dretvings shows this type t wave form. The other wove form,-see Fig. 3,-ie really n mere stendy direct current flow in the track, suddenl interrupted and im= mcdiately reversed. here is precticolly no choice between these two forms no regards their effectiveness in opcreting the polarized relay. lvlnny other forms of suddenly interrupted and gradually increased current would also he equolly good.

For the purposes or the erticulor truck current controlling circuit which. i. illustrate the reversed steedy current is assumed. This circuit, which I shall hcreeiter cell the track circuit, is merely illustrative. Signal controlling trcck circuits operehle with direct current in the tracks, with or Without reversols, also others With alternating currents in the tracks, ore so common and. so Well known in the art that without uestion many difl'crent end doubtless equal eifective errcn ements could be devised i or this port of t' c system by those skilled in the reilrvoy eig'nnl ort. n the prior art one of the greet ohstocleo hos been measure on the train the speed or the trovcl oi the trnin. Devices for this hove been ncrticulnrly t ouhlesome due to the diiiicuity oi"; providing it ileiiihlc choi't or n geared connection to n locomotive sole. The pounding end other conditioi'is ere ouch thot these connections constontly cut oi order. Expensive end cumbersome govern ore have even heen' devised with electriccl or other connections for this purpose.

lily this invention the distance trovclcd end the elapsed time for that trcvel ore concretely mentored or marked oil. Thin, in gencrolr has been done in the prior nrt; lent the one of codes or current impulses in the truck or roadside conductor to mark off time, has not to my knowledge been accomplished, end oi 'fcrs great edvontoges. If it foils, it hes the oilect of setting up the stop condition.

lln accordance with the present invention the indicator of revolutions is 0,, suitnblc interrupter ring with Wipers mounted directly on an axle of the locomotive and giving; electriccl impulses in the cob over conductors therefrom.

Prefernbly I em loy a. series of relays for counting the impu sec produced by said interrupter. Enid relcys have very slight inechonicel work to do, and each is operated at e frequency very many times lesethon that of: the main element in any of the mechanical types of counters known in the urt. l hove connected these relays as e set of counting relays, whereby the revolutions oi the exle tend to dccnergize them one by one, end so thct the timc mnrking truck code impulses tend to restore them ell. 1 thus not up, under certein conditions, it constnntly repented race between the axle tending" to count ell the relays down, and the time marking impulse Periodicnll restoring them all.

My invention owever may be practiced by usin any Well known type of mechanical or c cctromechnnicul revolution counter.

Gcnerelly stated, it system equipped with I the various features oi myinvention, opcrotee in the following menner:

A number oi timed codes of electriccl Weves, prelerebly hnving vcr abrupt portions, are up in the tram or in other ronclside conductors. The number of codes used is o metter of procticcl import and depends on conditions but the choice of these codes, so thet no toilures shell produce indications of false safety, is important. Simple moons are shown, but ony Well known means nioy he used, to determine how these codes succeed eech other in the blocks behind an occupied hioclr. ll hove shown, besides occupied, three conditions, etc i, cnution, end clear. Caution invo ves at speed limit. lnctesd of these three conditions, my invention con cqu'nlly well be practiced with, hcsides occupied, three or more diticrent speed limits, cs 10 miles per hour, 2&3 M. H. til li l. Elf, and unlimitcd The impulses up in the track ore inductively received on the trein, prefcrul'ily emplifim, end inclividuelly oicrote" o, receiving), reloy, pretcrehly of o no erizcd tyye. Fluilioient y frequent orierotions of this re ny, by mecns of its loccl contacts, pre'ferehly mcintein it locked or quiescent. condition of the control npperotuc. This is preferably accomplished by slow relensingg relays which do not rot time to release under there conditions. his is the clenr or full speed or unlimited condition.

The control opporotus include; o. recording device, lacing preferably 2 set oil counting reto record the distance troveietl since it ccrtcin inetnnt. This device is prcicrehly operntecl hy on electrical interrupter on an nrzle of the trnin. A pence in the frequent @pcrntione of the receiving reloy allows the fill llG

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avenues recording device to start recording the distance traveled, After the ,pause, operation of the same relay resets the recording device and restores briefly the mentioned quiescent condition of the control apparatus, unless during the pause, which is a feature of the code and predetermined in length a predetermined limiting distance was recorded. in this latter case the recording device has sev ered its own control by the polarized relay, cannot be reset thereby and so continues to record distance traveled until either the en grineer applies the brakes by hand ora further position of the device is reached which applies the brakes automatically.

An alternativais theinitiation of an automatic brake application by the recordingdo vice as soonv as the predetermined limiting distance has been recorded, the recording de vice stopping at this point, and a time lag being introduced in the application of the brakes whereby the engineer can manually forestall the automatic application if vi 1- lant. iluch a time lag may be produced y many well known means.

With air-brakes their automatic applications is preferably effected through deenerpining by the recording device a solenoid which has been holding closed an air valve, lit the engineer manually applies the brakes before the solenoid is deenergized the edect of the advanced position of the recording device must be neutralized, and tile latter restored to the control of the receiving relay. This is preferably accomplished by resetting the recording device part way, at least far enough to restore its control to the receiving relay, lfhe resetting: is preferably done by closing an electrical resetting circuit upon a manual bralre application; l' his resetting circuit, among; other methods of operation, is very suitably closed by some form. of pressure gauge matting an breaking a contact and pneumatically connected to the air line of the bralrcs.

if the receiving relay is a balanced or unbiassed polarized relay, which is preferable to the blessed type, it will stay put and gives no operations on repeated impulses of the same polarity. lln case, whether in the balanced polarised relay there are received repeated irnpuller-is of one polarity or whether in either type of relay no impulses all are received, long; continued period without operation of the receiving relay will ca so, by the means just described, an automatic application ofbralres unless forestalled by manual application. @bviously,

the train is not running, no distance will be recorded and the point of automatic applica tion on the recording device will not be reached.

llignals, preferably visual such as lamps, may be provided to be operated,e. p n. eatinguisheoh nt two or more positions or the re traclr and with diagrainin cording-device. he the structure is shown one lamp is provided to be extinguished when the recording device is unlocked ready to start recording and another is provided to be entinguished a trifle before the recording device reaches the point of severing itself from the control of the receiving relay. The'burnino of both lamps indicates the loclred or quiescent condition of the control apparatus which can only be due to frequent o erations of the receiving relay, i. e., to a c ear indication in the track, The extinction. of the first lamp indicates the beginning of apause codatherefore the reception of the beginning of a speed limiting or of a stop code. lfhe redightin the secon indicates that the pause code has ended-i. e. that the recording device has been reach-before excessive distance has been recorded. Extinction of the second lamp indicates that distance has been recorded nearly suflicient to cause application of brakes automaticall unless they already or promptly are app ied b hand. The steady burning, or the brief ol arkening or llichering of the second lamp especially, informs the engineer whether his speed is or is not within the limits prescribed, I further such that the restoring of the recording device (by a brake application) to the con trol of the receiving relay in no way affects the visual signals which at all times faithfully relate the indications received, and the agreement of train speed therewith. As shown, the first lamp is primarily the telltale of the kind of code received and the second lamp primarily betrays whether or not,

the distance recording device moves too in the time allowed by the pause in the code,

ll'large number of variations of these visual sials and of their relation to the distance recording device can be devised. For example, a series of small lamps, one satin guished by each step of the recording device, would quite graphically indicate to tire eny'i" neer the proportion of his speed to the limiting speed. lilnt the two lamps give all necessary indications are preferable therefore for reasons of snnplicity,

ln the drawings, Fig, l represents bloclt or section of track insulated adjacent bloclrs with a diagrammatic show a controller for producing codes of im ulses in the 2 r resentetion of a locomotive in the bloclr 23 represents one type of current wave to n that may be produced in the and cor responding voltage wave form induced the receiver. Fig. 3 represents another form of traclr wave and the corresponding}; voltage wave form in the receiver. are

P of the first without extinction oflhe arrangement shown is liltli schematic representations of various codes that may be used. Fig. 10 is a schematic illustration of as much of a simple form at receiving apparatus and receiving circuit on the usually comprise a relay locomotive as is necessary for a clear understanding of the invention by one skilled in the art. Fig. 11 is a schematic illustration of one form of the track code controller symbolized or diagrammatically shown at 3 and 6 of Fig. 1.

In Fig. 1, 1 are rails bonded to form each a continuous conductor from end to end. 2 are insulators electrically separating the rails of the one block from adjacent blocks. 3 is a circuit connection between the two rails at theentering end of the block and will or relays for signaling and other purposes. 4, as indicated, is a symbol for a locomotive carrying, ahead of the front wheels, inductors 5, more clearly shown in Fig. 10 in their relation to the rails 1. 6, as indicated, is a track current controller. Its function is the setting up of suitable codes of impulses in the rails of a block as determined by the condition of the track ahead. As is well known such controllers comprise a source of electrical current, either in the form of a generator or battery or in the form of power lines from a distant source or current supply, and an interrupter, switch, pole-changer, reversing device, rheostat or the like for making, brealring, reversing or otherwise varying the current blowing in a given circuit. Reasonably reliable speed controlling or time measuring means is also comprised in any such controller. The controller 6 need not even be situated near the track, but the conductors connecting thereto may be extended so that one controller may serve a number of sections of track. The connection between the controller and the track circuit may be inductiveas through a transformer-instead of conductive as illustrated. In fact any well knownmeans may be used to produce a current flow in the track of the character described. Merely to fix the ideas a suitable controller and a cooperative track relay are shown in Fig. 11 and will be described below.

The upper line of Fig. 2 is a graph or ourrent-change curve in which the horizontal dimensions represent time and the vertical dimensions above the line O-0 represent positive current and the vertical dimensions below the line 0-0 represent negative current. The lower line of Fig. 2 shows the corresponding voltage for the receiver and the two together illustrate how a gradual increase of current in the track induces a very small steady voltage in the receiver and how the abrupt dyin out of the current in the track induces in t e receivers relatively high but brief voltagewave corresponding in sign to the original: track current.

Fig. 3 is a graph substantially identical with that of 2, also showing track and receiver curves and illustrating how abrupt reversals of current direction in the track induce in the receiver relatively strong but rice brief impulses corresponding in sign to the track current impulse.

Fig. 4 symbolizes a preferred code of track impulses (or we may read them as in the receiver) which will ermit a locomotive carrying the. receiver oi Fig. 10 to travel at any speed at which the engineer may desire to run without automatic interference. This code I have termed the clear or unlimited code. In this figure and in Figs. 59 inclusive, horizontal dimensions represent, in a general way, time; the signs and above and below the line 0-0 represent each one an impulse of positive or negative polarity and are with equal logic in most cases understood to symbolize either or both the impulses in the track or in the receiver.

In the code of Fig. at, clear code, it will be seen that the time represented by the dimensions A is relatively brief between each impulse and the next effective one. in this case, and because an unbiassed polarized relay is utilized, the next efiective impulse is the next of the opposite polarity. Without limitation to an definite value for this time, and merely to in; the ideas, this eriod may be of the order of one second. t must be understood that, while this code is the only clear code illustrated, and is the preferred one for reasons of simplicity, any timed sequence of impulses will be satisfactory as a clear code in which the intervals between efiectively received impules are never longer than the suitable time A Thus a regular code of two positive impulses followed by two negatives and repeated indefinitely at, say, two second intervals would be the equivalent of the illustrated clear code of Fig. 4 assuming the polarized relay to be of the unbiassed type. If the polarized relay 23 of the receiving circuit Fig. 10 is biassed, which is readily done by adjusting its armature nearer to one pole than to the other so that said armature has a normal osition of rest when no current is flowing t rough coils 21 and 22 and does not, as I prefer it to do, remain on either side according to its last operation, then the clear code be comosed entirely of im ulses of the one polarity. uch impulses cou d be of the type of the positive track and receiver impulse forms of Fig. 2. They would have to be repeated at intervals suiiiciently brief, i'. e. at intervals not exceeding a time A found suitable to properly operate the receiving circuit.

Fig. 5 illustrates a code of impulses which, in cooperation with the receiving apparatus and circuit (Fig. 10) carried on the locomotive, will act to prevent the engineer from continuing at a speed higher than a certain predetermined limit when the locomotive is in a block in the rails of which this code is being produced. While the details of the. receiving circuit may be modified in many ways, in the disclosed receiving circuit, the

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ar-area code of Fig. 5 will automatically apply the brakes under certain conditions within a brief period after this code has begun to act upon the receiver. Une of these conditions is that the train be moving faster than a certain speed. Another is that the engineer has not by a manual application of the brakes already started to reduce the speed of his train. The above is merely explanatory oi the function of this code of Fig. 5 and the detailed conditions and operation will he more particularly described below. This code and those having the same general speed limiting function are herein termed caution codes. It will be observed that the time B in the code of Figs. 5-8 is the longest time between. efiective impulses. With an unbiassed polarized receiving relay the time between efl'ective impulses is the time from the first impulse of one polarity to the first of the opposite polarity. 'lime B is several times longer than the time A of the clear code. Merely to fix the ideas, we ma take timeB as of the order of seven secon s. it should be noted that one of the merits of timed impulse codes for controlling train speeds is that the times B ma be largely varied according to the speed imit desired by different railroads in different portions of one railroad, in difi'erent blocks behind an occupied block, even if desired at different times of the day or of the year, or for other reasons as may be dictated by experience.

With a biassed polarized receivingrelay this code might equally well be composed of nothing but positive impulses, e. g. of the type of Fig. 2, occurring at proper time intervals B. No clear or caution code'sof this type i. e. composed solely oi? im ity, have been illustrated the reason that the polarized relay 23 shown in Fig. 10 is not biassed, i. c. has a balanced adjustment and remains in the position to which it was last operated. Such unipolar clear or caution codes would therefore not cooperate with the receiver shown. The pos sibility oi using codes of one polarity is pointed out here merely to emphasize the fact that the intervals at time between efiectively received impulses are the most important distinguishing characteristics of these difibrent codes.

Fig. 6 illustrates a caution code identical with that-0t Fig. except that the first positive impulse induced in the receiver is succeeded by a series oi positive impulses having no cd'ect whatsoever on the preferred receiver, and the first negative impulse is likewise succeeded by negative impulses without effect. This variation is illustrated to show the flexibility oi the system and while of no advantage in the practice at this present inven tion as shown might be preferable to that of 5 for use in. connection with certain types ulses of one polar- 1n the drawings -for.

oil traclt current control or local signaling circuits or with certain types of track relays. ilhns if the traclr current-change curves oil Fig. 2 are used the code of Fig. 5 would in volve a relatively long time with no current in the rails l. and through the connection or track relay 3. ll we suppose 3 to be a signaling relay requiring to be held u during the caution code, trach impulses oi the form cl Fig. 2, repeated as in the code of Fig. 6, might with certain types of relays more readily accomplish this end for the signal engineer. The relationships between the codesin the one block and in the bloclr behind or before and the means of producing these relationships may be greatly varied within the spirit of this invention. The above remarks as to the possible superiority of thecode of Fi 6 under certain circumstances are merely llfiJlS- trative of the inherent flexibility of the present track current code system.

Fig. 7 illustrates a third caution code in which the time B, as before, is the period from the occurrence of the first impulse in the receiver of one polarity until the occurrence of the first of the o posite polarity. It differs from the codes oil igs 5 and it in that a brief period A is interposed between the longer periods B, and is typical of a whole class of possible, but not further illustrated, codes in which periods of clear code are'regularly interrupted by relatively long caution periods or code pauses B.

Fig. 8 illustrates a code identical with that of Fig. 7 except that the polarities are reversed and with the further exception that the times B are filled with repeated impulses of the one polarity after they manner of the code at Fig. ti.

Fig. 9 illustrates four of the many possi ble varieties of stop codes. These are codes which, cooperating withthe receiver ot Fig. 10, force the engineer to apply his brakes and lreep them on until his train comes to a dead stop under penalty of the Torches be it automatically applied. The one essenti characteristic that the tour codes illustrated in Fig. 9 have in common is that, with the @K". ception of a single first impulse in several cases, they produce no ell'ect whatewer upon the'receiving relay. They are, to all. intents and par oses, the same in edect on the receiver of J lg. it) as indefinitel long caution periods or code pauses lit at the various types shown in the caution codes elf Figs. iii--8, The first code shown in Fig. 9 is a seriesot re peated positive impulses only, i. e. necessarily impulses oi the general type of Fig. 2. lhe second code at 9 is series oi repeated negative impulses. The third shown is a long continued direct current ldow in the tract.

a positive direction, i; e. an indefinitely entcnded wave at the t pe ot the traclr wave at Fig. 3. it. continue tlow in the negative di rection in the traclr. would be another possiloil lid Mid

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thereof, at any oint ity. The fourth stop code shown in Fig. 9 is merely dead track, i. e. without current of any kind. Obviously, the third and the fourth are identical as far as the impulses induced in the receiver are concerned, and it will be seen when the receiver circuit of Fig. 10 is described, that all four are identical as far as effects on the polarized receiving relay are concerned.

The advantage of the last two stop codes will be particularly apparent when it is considered that the failure of the source of track current energy 8 of Fig. 1, the failure of the track current controller 6 of Fig. 1, the opening of the track circuit or the short circuiting between the locomotive and the control or 6, all not to produce this form of stop code. Likewise any failure of the receivin mechanism of Fig. 10 to receive the impu ses "that may be in the track, has the same effect on the train control mechanism as these last two stop codes. There is a similar advantage in the choice of the first two stop codes illustrated in Fig. 9 in that an failures in the track current controller the equivalent of the first or e acting one polarity only, or any failures in the receiver of Fig. such that it can receive or amplify one polarity only, result in t esecond stop code of Fig. 9. To those acquainted with the train control art the value is obvious of this choice of codes whereby failures produce the effect of a more precautionary signal.

In Fig. 10, 1 are the rails of Fig. 1 shown in cross section, 5 the inductors or inductive receivers each comprising an iron core mount-' ed on the locomotive in a position as near to the rail as the necessary clearances of railroad usage will permit. These cores are each surrounded by a winding 7 and these two windings are referably connected in series, and also in sue 1 a manner that the electromotive forces, generated in the windings 7 by changes of current in the rails 1, shall reinforce each other. The relative direction of flux in the two inductors, when the current in the track circuit is in one direction, is indicated by arrows on the dotted lines 8. From the inductors two conductors 9 and 10 lead respectively to the filament and grid of a three-electrode electron tube 12. 11 is a filament heatin battery or so called A batter 13 is t ieplate circuit battery usually cal ed the B battery. The plate circuit is completed by conductors 14 and 15 through the prime 16 of a transformer. 17 is the iron core til this transformer. 18 is the secondar conductors 19 and 20 complete the secon ar circuit through the windings 2i and 22 o a polarized relay 23. is illustrated this relay is electromagnetically polarized by ener 3 ram a battery 24 and a polarizing win ing 2!), but a permanent magnet may be used in place of an electronic. net as a source of polarizing hurt. The win 2. and 22 avenues are wound and connected in such a manner that a current flow in either direction in the secondary circuit 18, 20, 22, 21, 19 tends to produce 0 posite olarities at the poles 26 and 27. T e polarizing flux due to the winding 25 enters the armature 28 substantially at the center and a portion goes to the right hand half of the armature returning through ole 26 and the common frame 23 of the rey. A tportion of this polarizing flux goes to the le t hand half of the armature through pole 27 and returns through the common rame 23. Thus the flux due to the polarizing coil is in the same direction through both poles 26 and 27. The preferred adjustment of this relay is such that the pull of these two oles is substantially equal when tongue 29 is eld half-way between its two positions of contact with conductors 31 and 32.

At this point it may again be mentioned that if the relay were such that tongue 29, when no current flows in coils 21 and 22, always returned to lie on the same side, it would respond only to impulses of one olarity. If we assume that it lay as actually shown in the drawing, and if we call positive that impulse that will cause it to move to its other position, this makes clear the statement, above, that by biassing the polarized relay of the receiver a track code of impulses like those of Fig. 2 but of one polarity will be operative. As will be better understood after the whole operation of this receiving structure has been described, a very refined and exceptionally quick design for the left hand nick-acting slow-release relay 34 would in t is event be required. As stated above the biassed olarized relay would be less sensitive. T e change ofiers no sutlicient advantages over my preferred structure so far as I can perceive to compensate for these two disadvantages. It is possible again as stated above, that for certain track circuit purposes a code of one polarity would be a simplification.

Resuming the description of the structure as shown, the flux due to currents in the windings 21 and 22, being of opposite sign in the two poles, oppose the polarizing flux in the one pole and aids it in the other. Due to the well known law that the pull between a pole and an armature is'proportional to the square of the average density of the flux multiplied by the etl'ective cross section of the flux, this type of relay can be made responsive to very small impulses b increasin the polarizing flux. It is for his reason t lat electromagnetic polarizing means are preferred. All

of this polarized relay construction is of course well known in the art.

The armature 28 of the polarized relay carries a light tongue 29 which is grounded at 3G and which intakes contact in the one position to conductor 3]., in the other to conductor 32. This armature is pivoted on lml'fc ltill till till

intense edge 38 and in the absence of current through windings 21 and 22, retains the contact which it last made with some firmness due to the polarizing flux which holds the armature stron l to the nearer one of the poles 26 or 27. iii the diagram more polarizing flux is temporarily passing through pole 27 than through pole 26 because of the temporarily larger air gap at ole 26. The ten ue29 is therefore firmly old in contact wit conductor 31.

Polarized relay tongue 29 due to received and am lified impulses of alternate polarity closes tde circuit alternately from ground 30 through conductor 81 .or 32 and either one of two quick-acting slow release relays lid to battery and ground. Relays 84 may be of any suitable construction well known in the art but are very simply and preferably made of the sim lost I). C. relay form with the addition of a lieavy copper collar or sleeve 35 which, acting as a short circuited secondary, renders the action of the relay sluggish, more especially on releasing. By a suitable adjustment and by usin a proper amount of energy in thecoils 0 these relays, they can be made much slower in releasing than in attracting their armatures 36.

The armaturee 36 of quick-acting slow-release relays 34, when these relays are enerized, close a series circuit from ground t rough the two armatures 86 and their two front contacts 87 conductors 38 and 67, the extreme left hand contact ot' relay e, conductor 39 and the left hand winding of relay 40 to battery and ground. A branching circuit 41 from conductor 6'8 includes a green signal lam 42 normally in parallel with the left han winding of relay 4.0. 1

Relay do is shown with two arniatures, but this is done for sim )licity in the diagram. This relay and those like it in the drawin are preierab y of one of the well known G. types having an armature closing, when onergized, two or more separate circuits. For brevity l shall hereafter refer to the right and left hand armaturee just as shown on the drawing. Relay 40 has a right hand winding connected-aiding the left hand wind lug-through the right hand armature when 40 is energized and then through conductor it! to a wiper it which bears on an interrupter 4h. interrupter til has a relatively short inaulated segment and a grounded conducting segment. .lt revolves in a clockwise direm tion as viewed in the drawing. and it carried by or operated ironi a wheel or uric oi the locomotive. A second wiper 46 hours on in terrupter til at aubatantially ltltl" distance ironi wiper 4t and tends ground to certain relay armaturee through conductor til an will be explained below.

The let't hand armature at relay i0 is grounded and, when relay til it cnergiaed, closes the circuit to conductor til right hand winding oi relay lit) to battery through the and ground. Relay 50 has a left hand winding of which the circuit is closed from the grounded interru ter through wiper 46, conductor 47 audits own left hand armature to grounded battery when relay 50 is energized. This circuit is of course open at the interrupter when wiper 46 is on the-insulatsegment. The right hand armature of relliy 50 is grounded and, when 50 is energized, closes a circuit containing the left hand winding of relay 60. The relay has a right hand winding the circuit of which is closed when it is energized through its own right hand armature, conductor 43, wiper 44. and grounded interrupter 45. This circuit is of course open at the interrupter when wi er 44 is on the insulating segment. The lift hand armature of relay 60 is grounded and; circuit containing when energized closes a the right hand winding of the next counting relay,not shown,--and so on for an indefinite number bf relays. The number of these relays to be used, which l'have termed the counting relays, is dependent on the speed limits to be enforced and the length chosen for the code auses or caution intervals B. For simp icity in the drawings I have shown of tiis first series of counting relays only the first three designated 40, 50, 60 and the last three designated to, I, .2. It will be clear from a comparison of t e figures on the drawings that the relay to is connected exactly like the relay 50, the relay 3 is connected exactly like the relay 60, and the last relay 3 a min like relay 50..

clay in is energized through its right hand winding by the left hand armature of the preceding role and is periodically energized through its le t hand winding by its own left hand armature and the wiper to of interruptlhe grounded'right hand armature.

or to. of rela w closes, when the relay is energized, an ad itional circuit through and yellow signal light 51 to grounded battery. Relay e is, by conductor 68, connected to the first relay 40 of a second or continuation series just as relay 50 is to 60. Relay 40" is succeeded by another relay shown), and so on to the last relay e. simplicity oi the diagram only the first and thelast relays 40 and a are shown of this second series.

llelay a by its rounded right hand arma-= ture and contact iolds energized solenoid 53 over the circuit including conductor 52, the

winding oi t3, solenoid loching spring lit,

conductor till. to grounded hatter 'lho solenoid til while energize maintainer the valve rod 58 and valve ll in the u ward position shown. 58 is the body at an e entropneumatie valve which comprises eoleneid ht, valve red 56 and valve ill and la shown in section. ht ie an air pressure connection i'i'iiin""tliolnalte-ioontrolling air line oi the train. lit in unearned that a reduced preaeure conductor 49-,

(rootor till ltltl lltl ll id ltd ltd

in this air line applies the brakes. 61 is a tension spring to assist gravity in opening the valve 57 when solenoid 53 is deenergizegl. 62 is a manually operable key for closing the circuit of the solenoid when it is deenergized and when in consequence spring 54 is not in contact with conductor 55. 63 is an insulated mechanical connection to a pressure gauge or the like,not shown,-connected to the air brake system in such a way that if brakes are applied adequately 63 presses against contact spring 64 closing a circuit from ground through conductor 65, through the left hand coil of relay y to battery. Thus 64 is an alternative to, and in multiple with, the right hand armature of relay :0. 66 is a sealed receptacle or box enclosing the electropneumatic valve, the solenoid 53, the key 62 and preferably also enclosing the pressure gauge contact elements 63, 64. This receptacle or box and its seal may be of any well known construction. Its purpose is to prevent the engineer from closing the electropneumatic valve if it once opens without eaving proof that it has been open.

Assuming the locomotive 4 to be receiving the clear code of Fig. 4 or any equivalent code comprising continuous sufliciently rapid alternations of positive and negative impulses in the track, the operation is as follows: The current flow in the track, whether gradually increasing as diagrammed in the upper line of Fig. 2 or steady as in the upper line of Fig. 3, sets up fiux about the rails a portion of which, 8, is led by the iron cores 5 of the inductors through the windings 7. The abrupt interruption or interruption and reversal of the current flow in the track causes the sudden dying out or dying out and re versal of the flux 8. This sets up in windings 7 a relatively high electromotlve force the relative instantaneous polarity of which isdependent upon the original direction'of current flow in the track. This electromotive force raises or lowers the potential of the grid of the threeelectrode electron tube 12 and causes a corres ending sudden increase or decrease in the ate current flow from battery 13 through figment and plate of 12, conductor 14, primary winding 16, and conductor 15. It will be noted that, as is well understood by those skilled in the art of amplification by electron tubes, this current will vary in magnitude but not in direction. By the use of the transformer 16, 17 and 18 these sudden increases and decreases of the plate current are again converted into positive and negative impulses in the circuit 18 19, 2 1 22, 20.

15 explained above, these posit ve and negative impulses through the windings 21 and 22 of the polarized relay 23 throw the contact :ongue from side to side, alternately ens 34. Relays 34 are designed *nainm .neir armatnres attracted fer a brief period the circuit of their wind- Lmaaee ings is open and this period must be somewhat greater than the period A between alternate impulses of the code of Fig. 4 or any equivalent clear code that may be used. Relays 34 are also designed to attract their armatures 36 in a period somewhat less than the period A. Thus when the code of Fig. 4 or an equivalent is being produced in track 1, and when in consequence tongue 29 of po larized relay 23 is alternately in contact with conductors 31 and 32 for equal periods of duration A, both relays 34 maintain their armatures 36 attracted and a circuit is closed from ground through these armatures, through conductor 41 and green lamp 42 to battery, and in parallel with the latter, through conductor 67 left hand armature of relay 2, conductor 39 and left hand winding of relay 40 to battery. The green signal light burns steadily and relay 40 remains energized. Relay 40 by its left hand armature maintains relay 5O energized. Relay 50 by its right hand armature maintains relay energized and so on to the end of the series, all the relays 40 to a remaining energized. The right hand armature of relay a2 closes the circuit of the yellow signal lamp 51, which burns steadily. Relay 2, by its right hand armature, also maintains closed the circuit including conductor 68 of the left hand winding of relay 40. Relay 40" holds energized the next relay, and so on to. relay e which by its grounded right hand armature and through conductor 52 maintains solenoid 53 energized throu h spring 54 and conductor 55 to battery. olenoid 53 holds closed the valve 57 and air from the brakes cannot escape from valve chamber 58.

The only moving elements in the circuit on the locomotive under these conditions are the armature and tongue 28 and 29 of polarized relay 23 and the continuously revolving interrupter 45 connected to a locomotive wheel. This may be called the normal or locked condition of the receiver.

Assuming, now, the locomotive to be on track containing a caution or speed limit code of one of the types illustrated in Figs. 5-8 or equivalent, the operation is as follows:

Omitting the repetition of the detailed operation of receiving, amplifying and transforming the impulses, it will be clear from the preceding explanation that at the beginning of one of the caution code intervals, or code pauses, designated by the letter B in Figs. 5-8, polarized relay tongue 29 will be positively thrown to one side or the other and will there remain until the end of the period B. The period B is much longer than the period during which relays 34 can, without current in their windings,-maintain their armatures attracted. Une of these relays 34 will therefore, after the lapse of time somewhat greater than A, release its armature and open the circuit both of the green nuance lamp and of the left hand winding of relay 40. The green lamp will go out. Relay 40 will be maintained energized by its right matic.- In this case, w

hand winding for a period varying from zero to nearly the time of a complete revolution of interrupter 45, but clearly will be deenergized when wiper 44 goes over insulating segment 45. It will then unlock itself by its right hand armature so that it cannot be again re-energized by the circuit from ground through wiper 44 and conductor 43. The left hand armature of relay 40, being released, deener izes the right hand winding of relay '50 which remains energized by its left hand winding until wiper 46, in its turn, goes over the insulating-segment of 45. Rela is then unlocked and deenergizes one win ing of which is next unlocked by interrupter 45, one-half revolution later, and so on.

The rela s of the series are thus unlocked one after t e other at intervals measured by a half revolution of interrupter 45. The rate at which the whole series of relays is unlocked is therefore directlydependent upon the speed of the train.

If we assume the speed of the train to be higher than the limiting speed redetermined by the caution code in use an if we assume that the engineer is negligent and has not.

noted the caution signal on the roadside semaphore, if there is one, and has likewise not seen the extinction of the green signal light in the cab of the locomotive and acted promptly, then relay m, which is the second from the last relay of the first series, will release its right hand armature, extinguishing the yellow signal light 51.- Relay y and relay 2 are next unlocked. Relay 2 by its extreme left hand armature opens the connection between conductors 67 and 39 and makes it impossible for relays 34 to reenergize the left hand winding of relay 40. At this point. of the operation, and by this action of relay 2, a prompt brake application is irrevocably determined.

There remains the question whether it shall be an automatic application or a manual one. If the manual application is delayed until the second series of relays, 40"--z, are all deenergized, the ap lication will be autoen deenergized, relay 2' by its right hand armature removes ground and releases solenoid 53. Valve 57 opens, aided if necessary'by spring 61. Pressure in the brake air line is reduced and brakes go on. Contact 54, 55 is opened and the circuit through the solenoid cannot berestored unless box 66 is opened. This will leave a rec- Key 62 is provided within the box as an 'easy means of restoring the circuit for reenergizing solenoid 53 when the box is open: 7 e

Preferably a reduction of pressure in the brake air line sufficient-to apply brakes adequately, whether due to the automatic openand 7 locking the box.

ing ofvalve 57 as just described or to the opening of a manually operated valve, and acting through any well known pressure gauging means, closes a circuit as follows: from grounded spring 64, through conductor 65, left hand winding of relay 3 to battery ground. By this circuit relay y, if deenergized, will be reenergized and will reenergize relay 2, this in turn reenergizing 40 and so on till relay 2 is reenergized. This, as explained, cannot however restore the electropneumatic valve because the solenoid circuit is open at contact 54 55. Thus the engineer cannot release the brakes without un- But if this reenergizing process is initiated by a manual application of the brakes, i. e. if just before relay 2 and solenoid 53 are unlocked the circuit ground, 64, 65, right hand winding of relay 3/ to battery and ground-is closed the deenergization and unlocking of the solenoid will be forestalled. 1

Instead of pneumatic pressure or other pneumatic means to close the contact 64, 65 when brakes are applied, an well known or obvious mechanical electrica or other means may be employed. This is a matter in which the nature of the braking system in use will be controlling, and one that will offer no difficulties to those skilled in the art. As stated above, contact 64, 65 is only preferably located in sealed box 66. It may be more convenient to locate it elsewhere. It should be so devised as not to be operable except by a brake application of predetermined force or greater.

At the end of the caution cycle B the polarized relay tongue 29 swings to the other side, the deenergized one of relays 34 becomes energized and the circuit of the green lamp is again "closed. If at this time relay 2 is energized the circuit of the right hand winding of relay 40 is also completed. Relay 40 by its left hand armature energizes relay 50, relay 50 energizes 60 and so on with extreme rapidity to the end of the deenergized series, i. e. down through relay y in the extreme case, these relays being quick-acting. The yellow lamp will again start to burn.

But another caution cycle B may begin at once and one of the relays 34, after a certain period a little lon er than A, releases its armature, the reenlight is extinguished, and the process or successively deenergizing relays 40, 50, z z again begins. It is thus clear that as long as the speed of the train is such that interrupter 45 deenergizes all of the relays 4O a; before the end of caution cycle B, the green lamp will flash on very briefl and the yellow lamp'will flash off very brie y. I

If we assume that the engineer noted the roadside caution signal or the first extinction deenergized the whole series of relays, he will close the spring 64 to conductor 65 and thereby will maintain relays y, z a and consequently solenoid 53 all energized and valve 57 closed. This is the case even if relay 2 had released its right hand armature before the fresh impulse was received from the track. As lon as he maintains the brakes on with sufiicient force, contact 64, 65 is closed and the automatic application of brakes by the release of solenoid 53 is avoided. When he has reduced the train speed to a point where the interrupter 45 cannot count down all of the relays 40 2 before a fresh impulse at the end of the caution cycle B, by reenergizing the deenergizd relay 34, sets them all up again, he may if he wishes release the brakes. that he has sufiicientl reduced the train speed to release brakes, an with a little margin of safety, by the cessation of the flashbriefly off-of yellow lam 51. This margin of safety is provided y connecting lamp 51 to a relay one or two earlier in the series than the relay 2. If, without this margin of safety, he should unconsciously allow the train to speed up a very little he might receive an automatic application of brakes which would not be heralded by earlier flashings of yellow lamp 51. He would therefore require accurate speed determining means and would also be forced to remain well on the safe side of the speed limit.

It will be noted that the cab signal lamps 42 and 51 are not affected by the restoring of relays y 2 by any brake application. The rela s 40 w are still subject to their two con icting controls, the polarized relay by way of relays 34, 34 tending at intervals to restore them and the interrupter 45 tendin steadily to deenergize them one by one. Tl us the lamps continue to give significant indications as to the code that is being received-particularly lamp 42,-and as to whether the train speed has or has not been brought within the required limit-particularly lamp 51.

In view of the fore oing explanations, the action of any stop code will be immediately clear. One of the relays 34 releases its armature permanently or until the stop code is succeeded by a caution or clear code. The green lamp goes out permanently. The rela s are counted down and are not restored y the polarized relay, since noTeffective track impulses are coming in.

yellow lamp goes out permanently. If the rakes have not by this time been manually applied, an automatic application of brakes occurs when relay 2" is deenergized. Assuming that the engineer has applied the brakes early enough to forestall t e automatic application thereof, as long as both the green and yellow lights remain out and if the train is still moving he may not release the brakes He will know under penalty of their being'automatically applied almost at once.

[11 this connection it may be remarked that from a practical standpoint some railroad operating men may prefer, instead of using an absolute stop code for indicating danger ahead, to use a code of the type of the caution codes but in which the pause B is so extended as to limit the train speed to 5 or 10 miles an hour. This will 'allow the engineer to advance slowly in a danger block with his brakes off.

The reason for causing a brake application to first energize relay y instead of relay 2- which is the one that directly controls the circuit from the slow-release relays 34, 34 to relay 40-is that the train will often be stationary in a stop block with wiper 46 on the insulating segment of the interrupter. If conductor 65 were broughtdirectly to the right hand winding of relay 2 any application of brakes would pull up a but with the above conditions existing 2 would again be deenergized upon release of brakes. This would force the engineer to stand in a stop blockor even in an occupied block, which has the same effect on the receiver-with his brakes on all the time. He should be permitted to release them. And the reenergization of relay y, prior to 2, by the brake application assurcs that relay 2, at least, will remain energized when the contact 64, 65 is opened. For'obviously the insulating segment of 45 cannot be under both wipers 44 and 46 at the same time.

In Fig. 11, S is a source of electrical energy,-see Fig. l-and is here shown as a battery including a protective resistance and a fuse F. The source S might equally well be a generator or power lines fed from a distant source. To cooperate with the structure of the track current code controller 6 shown, S must be a source of direct current.

My invention, however, may be variously practised, as was suggested above, and among other variations S ma be a transformer or set of transformers or 0 power lines selectively delivering (conductively or inductively) into the track circuit series of current waves of substantially the characteristics shown in Fig. 2 and of the proper sequence, polarity and timing to constitute the required code for the conditions of the moment. In other words the code currents may be produced at a distance,-intsead of locally by a battery and interrupters as shown and as I am about to describe in detail,-transmitted over wires to the different controllers 6 along the roadbed, and selectively fed by them to the track circuits in substantially the same manner as, in Fi 11 I feed the locally generated codes.

n controller 6,shown in Fig. 11 surrounded by a dotted line, 69 is an interrupter or rather a reverse! or pole-changer fed by the battery loads 71, 72,-respectivcly+and. throng 1 wipers 73 and 74 bearin on collector rings 77 and 78. Wipers 75 and 76 bear alternately'on the+and the-conducting segments of reverser ring 79. The insulation between these segments is wider than the bearing surface of 75 and 76 so that they are both simultaneously insulated from the battery S for a very brief instant. Wipers 75 and 76 and the leads 81 and 82 therefrom thus deliver brief periods of steady current alternating in polarity rather than ordinary or sine wave alternating current. The frequency of the alternations is determined by the speed of shaft 83 which I have marked fast in the drawing. Reverser 69 produces clear? codes.

Shaft 83 may be driven by any suitable motor,-e. g. an electric motor drawing energy from source S,and this motor must have quite constant speed. A small D. 0. motor with governing means to compensate for voltage changes would be suitable. Shaft 83, being properly geared to the motor, revolves at such a speed that one half revolution takes the time A of the clear code.

84 is an exactly similar reverser, except that the speed is such as to produce caution code. It need not be further described. Conductors 85 and 86 then deliver slow reversed direct current according tothe code of Fig. 5 and with wave forms substantially like those of the upper line of Fig. 3. The shaft of reverser 84 is preferably geared, in proper speed relation to shaft 83, to the same motor.

The wave forms of Fig. 3 show no break or bend in the curve between the interruption of, let us say, a positive current flow and the establishment of negative flow. This is possible. by reversers like 69, ifthe time during which wipers and 76 are entirely insulate from the battery is more brief than the time necessary for the current flowing in the track circuit to decay to zero. This requires, if accidental short circuits are to be avoided, either a very close adjustment of the widths of the insulation and of the wipers, or a relatively large surfacespeed of reverser ring 79. The latter is preferable and obtainable by making the diameter of 79 large in relation to the width of wipers 75 and 76.

It is noteworthy, however, that using as I do in Fig. 10 an unbiased polarized receivin relay, this refinement is not necessary. I sometime after current in the one direction has been interrupted, current in the opposite direction is sharply set up in the track, the result as far as the receiving circuit on the locomotive is concerned is merely that two impulses of the same polarity are received in rapid succession. The first will have practically always the higher voltage and the shorter duration and will operate the polarized relay. The second will have no effect.

Moreover, other forms of reversing devices, with a quick spring or magnetic action are well known and can be equally well used.

The commutator and carbon brush type I find referable from the standpoint of general urability and reliability of contact. In

any case should either reverser slow up, stick,-

lose contact, or be short circuited and blow the fuse F, the code fed to the track will enforce a lower train speed, or produce the effect of stop code.

87 is a polarized relay, biasedand it is shown biased by a spring 88, though it may be biased by unbalanced polarizing flux-and for economy only shown with a permanent polarizing magnet 89. Its armature is grounded. It is connected across theentering of two blocks Nos. 1 and 2, are visiblle, the

drawing of relay 87 has not been repeated for block N o. 2, and conductors 91, 92 leading to another and to be imagined similar polarized relay across block No. 2 are merely indicated ending in arrows. This is also the treatment of the two visible front or exit ends of blocks Nos. 2 and 3, and of the conductors 93, 94 or 93 94 feeding them from code controllers 6. Only controller 6 feeding block N o. 2 is shown.

Tongue 95 of relay 87 alternately makes contact, either rapidly or slowly, on conductors 96 and 97, if in block No. 1 the existing code is clear or caution. Two extra slow relays 98 are thus energized by tongue 95, one through conductor 96 and one through conductor 97. Relays 98 are shown equipped with heavy copper collars, to indicate slow-.

ness. They are preferably of a mechanicaltion if such long code intervals are chosen is of a well known type involving angular acceleration of a balanced mass or flywheel by a relatively weak force applied by the attracted armature, and is such that the energy of successive impulses is largely stored in the mass. A weak spring or light weight opposes the armature attraction. If, however, more rapid caution codes are chosen, electrically sluggish relays are suitable, and can be produced at reasonable expense.

When, therefore, either clear or caution code is in block No. 1, extra slow relays 98 attract and hold attracted their armatures and a circuit is closed from battery through their armatures in series, through conductor 99 and the windingof relay 101 to ground.

Relay 101 attracts its two armatures and connects the leads 81, 82 which yield clear code, to the track feed wires 93 and 94 of block No. 2. Thus clear or caution in one block establishes clear in the block behind.

Let us assume that in block No. 1 the stop code is set up. As the polarized relay 87 is, more or less fortuitously, shown biased to res nd to positive current, it is necessary to c oose as t e stop code to cooperate therewith the one shown on the third line of Fig. 9, namely, continued stead current in the positive direction. Oppositely biasin the relay 87 would require using for stop code a continued negative current. Assuming then a continued positive flow in block No. 1 and therefore through conductors 91, 92 and the winding of rela 87, the right hand extra slowrelay 98 is hel energized, but the left hand relay releases its armature. It is readily seen that a circuit is thus closed energizing relay 102 and thereby applying to feed wires 94 and 95 the caution code always in loads 85 and 86. Relays 101,102 and 103 must be relatively quick to release, and slow to o erate, in order that two codes shall not be ed simultaneously with probable short circuits. We now have stop code in .block No; 1 causing caution code to be fed to block No. 2. This'in turn will cause clear code to be fed to block No. 3.

Assume now that block No. 1 is occupied and that the entering end is therefore dead. Relay 87 lies as shown in Fig. 11. Relays 98 stay as shown, and a circuit is set up energizing relay 103 and feeding steady current in the positive direction from battery leads 71, 72 to feed wires 93, 94 and to track of block No. 2. This is the stop code chosen. We thus have the occupied block No. 1 setting up sto code in block No. 2. This in turn, as detailed above, sets up caution code in block No. 3, which again sets up clear code in block No. 4. And clear code in block No. 4

re roduces itself in No. 5 and so on.

hat I claim is:

1. In a train control system, a track section, a vehicle movable thereon, meansto produce in said track section discrete electrical impulses on a plurality of different time interval patterns corresponding to a plurality of difierent o erating conditions for said track section, an a receiver on saidvehicle having a group of elements responsive to individual discrete impulses in the track section and having another grou of elements responsive to their time interva pattern.

2. In a train control system, a track, vehicles on said track, means to produce in said track a code" of abrupt electrical current changes occurring at predetermined intervals, a receiver on one of said vehicles responsive to abrupt current changesin the track and comprising amplifying means, a relay responsive to an individual abrupt current change in said track, and a train control means dependent u on said relay. i

3. In a train ontrol system, a track, a vehicle thereon, a wheel of said vehicle rolling on said track, means to set up timed current changes in said track, a time marking receiver element on sai vehicle inductively operated by said timed current changes, a travel-indicating receiver element comprising said wheel, and train control means 'ointly dependent upon said time marking element and upon said travel-indicating element.

4. In a train control system, a track, vehicles thereon, means to produce in said track a plurality of codes of discrete electrical waves diifering in their timing, a receiver on one of said vehicles variably responsive to the different codes, a relay in said receiver operated by individual ones of the discrete electrical waves, a travel-indicating device and a vehicle-control means jointly dependent on said receiver, said relay, and said travel-indicating device.

5. In a train control system, a track, a vehicle on said track havin a wheel rollin thereon, a means to prodiice in said tracE tmed discrete electrical impulses, a receiver on said vehicle for receiving the timed impulses and responsive to single discrete ones of said impulses, an interrupter operated by the wheel of said vehicle, a series of relays successively controlled one after the other by said interrupter in such a manner that a definite group of relays corresponds to each cycle of said 1ntcrrupter,-and means whereby said series of relays are controllable substantially as one group by said receiver.

6. In a train control system, means for producing predetermined cycles of abrupt current changes in a track, inductive receiving means on a vehicle wherein brief inductive impulses are generated by the abrupt current changes in the track, an amplifier, a polarized relay on said vehicle operable by an indi-' vidual brief inductive impulse generated in said receiver, and a train control circuit dependent upon the cycles of operation of said polarized relay.

7. In a train control system, a.track, a vehicle on said track, a track code generator producing timed cycles of electrical impulses in said track, a receiver on said vehicle operatin in response to individual impulses in said track, a wheel on 'saidvehicle, means to count the revolutions of said wheel whereby distance is measured, means to compare the times of operation of said receiver andof said means to count whereby speeds of said vehicles are determined, and a train control means operable by said means to compare.

8. In a train control system, a track, ve-

hicles on said track, a generator setting up in said track vehicle signaling codes comprising abrupt electrical current changes of predetermined sign and at predetermined ining recurring cycles tervals, a vehicle signaling receiver in which brief electrical impulses are induced responsive to the abrupt current changes in said track, a relay selectively operated by said receiver in accordance with the polarity of the brief electrical impulses induced therein, a source of electrical energy on said vehicle, a train speed controlling means energized from said source, and means whereby said train speed controlling means is rendered temporarily ineffective by the operation of said relay.

9. In a train control system, a track, a vehicle on said track, means producing in said track timed impulses, an inductive receiver on said vehicle, an amplifier on said vehicle, a polarized-relay on said vehicle operable by individual impulses in said track, a slow release relay operated by said polarized relay, a vehicle Wheel, an interru ter operated by said Wheel, and a series of countin relays energized as a group by said slow-re ease relay and individually deenergized one after the other by said interrupter when said slowrelease relay is deenergized.

10. In a train control system, a track, a vehicle on said track, means producing in said track timed impulses, an inductive receiver on said vehicle, an amplifier on said vehicle, a polarized relay on said vehicle operable through said receiver and said amplifier by individual impulses in said track, a slowrelease relay operated by said polarized relay, a vehicle wheel, an interrupter operated by said Wheel, a series of counting relays energized as a group by said slow-release relay and individually deenergized one after the other by said interrupter when said slow-release relay is deenerrized, electromagnetic brake control means, and a train control contact on one of said counting relays to control said electromagnetic brake control means.

11. In a train control system, a track, a vehicle on said track, means to produce in said track a code of electrical currents havof change whereby time is measured, a receiver on said vehicle responding to each cycle of change, a device registering distance, on said vehicle, and means for resetting said device operated by said receiver.

12. In a train control system, means to produce in a track electrical currents having recurring cycles of change for indicating time. a vehicle, a receiver thereon responsive to each cycle of change, a device measuring the travel of said vehicle, a means to reset said device operated by said receiver, and means to control the vehicle operated by said device if greater than a predetermined travel is measured by said device before it is reset.

13. In a train control system, means to produce in a track electrical currents having recurring cycles of change for indicating time, a vehicle,

a receiver thereon responsive to each cycle of change, a device measurin the travel of said vehicle, a means to reset said device operated by said receiver, and means operated by said device automatically to check the speed of the vehicle and to produce a distinctive signal on the vehicle if greater than a predetermined travel is measured by said device before it is reset.

14. In a train control system, means to produce in a track electrical currents havin recurring cycles of change for indicating time, a vehicle, a receiver thereon responsive to each cycle of change, a device measuring the travel of said vehicle, a means to reset said device operated by said receiver, a manual braking means, automatic means operated by said device to apply brakes if greater than a redetermined travel is measured' by said evice before it is reset, and means operated by the operation of said manual braking means to prevent said automatic means from operating if said manual braking means is operated before said device has measured said predetermined travel.

15. In a train control system, means to'produce in a track electrical currents having recurring cycles of change for indicating time, a vehicle, a receiver each cycle of change, a device measuring the travel of said vehicle, a means to reset said device operatedby said receiver, a distinctive signal to declare the starting of said device measuring travel, a distinctive signal operated if greater than a. redetermined travel is measured by said device before it is reset, brakes, automatic means applying said brakes after said second signal is given, and manual means operable to apply said brakes and While in operated position preventing said automatic means if operated before said automatic means.

16. In a train control system, means to produce in a track electrical currents having recurring cycles of change for indicating time, a vehicle, a receiver thereon responsive to each cycle of chan e, a device measuring the travel of said vehlcle, a means to reset said device operated by said receiver, a distinctive signal to declare the startin of said device measuring travel, a distinctlve signal operated if greater than a predetermined travel is measured by said device before it is reset, brakes, automatic means applying said brakes after said second signal is given, and manual means operable to apply said brakes and while in operated position preventing said automatic means if operated before said automatic means, and means including said sec- 0nd signal to indicate when said device is reset before it has measured the predetermined travel, whereby an indication is given that said manual means may be restored nonoperated position without the 'operatlon of said automatic means.

17. In a tain control system, a track, ve-

thereon responsive to hicles on said track, a track controller system successively to set up in said track currents in two directions and abruptly to terminate them in predetermined cycles, a receiver on one of said vehicles wherein cycles of brief impulses of two polarities are induced respondent to the aforesaid cycles of abrupt terminations of current in said track, a receiving circuit'comprising a source of electrical energy and means to control said source of energy to amplify the brief impulses produced in said receiver, a transformer in said receiving circuit, a polarized relay selectively responsive to the polarity of individual impulses produced in said receiver, a vehicle wheel, means to count the revolu tions of said wheel, and a train control magnet controlled by said polarized relay and by said means to count.

18. In a train control system, a track, vehicles on said track, a track controller system to set up in said track currents in two directions and abruptly to terminate them in predetermined cycles, a receiver on one of said vehicles wherein cycles of brief impulses of two polarities are induccdrespondent to the aforesaid cycles of abrupt terminations of current in said track, a receiving circuit comprising a source of electrical energy and means to control said source of energy to amplify the brief impulses produced in said receiver, a transformer in said receivlng circuit, a polarized relay selectively responsive to the polarity of individual impulses produced in said receiver, a vehicle wheel, a circuit breaker operated by said wheel, a series of relays controlled by said circuit breaker over alternate paths to register the revolutions of said wheel, a vehicle brake, a brake control means applying said brake after a )redetermined number of revolutions of said wheel have been registered by said series of relays, and means controlled by the operation of said polarized relay to clear said series of relays of any registered revolutions at predetermined intervals whereby said brake control means is prevented from applying said brake if said polarized relay operates at intervals sufficiently brief relatively to the speed of revolution of said vehicle wheel.

19. In a train control system, a track, vehicles on said track, a track controller system to set up in said track currents in two directions and abruptly to terminate them in predetermined cycles, a receiver on one of said vehicles wherein cycles of brief impulses of two polarities are induced respondent to the aforesaid cycles of abrupt terminations of current in said track, a receiving circuit co1nprising a source of electrical energy and means to control said source of energy to amplify the brief impulses produced in said receiver, a transformer in said receiving c1rcuit, a polarized relay selectively responsive to the polarity of individual impulses produced in said receiver, a vehicle wheel, means to count the revolutions of said wheel, a vehicle brake, a brake control means ap lying said brake after a predetermined num er of revolutions of said wheel have been registered by said means to count, and means controlled by the operation of said polarized relay to clear said means to count at predetermined intervals whereby said brake control means is prevented from applying said brake if said polarized relay operates at intervals sufficiently brief relatively to the speed of revolution of said vehicle wheel.

20. In a train control system, a track, a moving vehicle, a track impulse timer producing positive and negative impulses in said track, a receiver on said vehicle comprising a polarized relay, an armature forming part of said polarized relay permanently left in one position following a positive impulse and permanently left in an alternate posltion by a negative impulse, and means to compare the time said armature is left in one position with the time taken by said vehicle to move a predetermined distance.

21. In a train control system, a track, a vehicle on said track, a source of electrical energy to furnish energy for impulses insaid track, a code timer to determine a plurality of different codes of impulses of two polarities in said track, the codes differing by. the time elapsing between impulses of opposite p0- larity and a receiver on said vehicle different- 1y responsive to the different codes.

22. In a train control system, a track, a vehicle on said track, a wheel of said vehicle rolling on said track, a travel-indicator comprising said wheel, a receiver on said vehicle comprising a relay having two positions and train control elements on said vehicle operatively dependent on the time between reverses of pos'tion of said relay and on the indications of said travel indicator.

23. In a train control system, time measuring means including a track impulse timer and a receiver, distance measuring means comprising a wheel, a circuit controller' connected to said wheel and a series of energized relays successively deenergized by said controller, and hold over means briefly to delay deenergization of one of said relays.

24. In a train control system, a track, a vellO hicle, a circuit-controlling device on said vehicle, and a counter variably operable by a plurality of groups of impulses, said counter comprising at least one relay for each unit to be counted.

25. In a signaling system, a set of counting relays, means for producing two distinct signals, an energizing circuit for one of said relays closed in response to the production of one of said signals, energizing circuits closed for all said relays upon the energization of said one of said relays, means responsive to the production of the other signal for nal, an interrupter,

. circuits.

26. In an impulse counting system, a set of counting relays, an energizing c rcuit for one of said relays, energlzmg circuits closed for all said relays upon the energization of said one of said relays, an interrupter, and a'separate energizing circuit for each relay controlled bysaid interrupter.

27. In a'counting relay circuit, aseries of energized relays, each energized by a path through a front contact of'a prior relay, a control circuit likewise energizing alternate relays of the series, a second control circuit energizing other alternate relays, an interrupter alternately opening the two control circuits and deenergizing the relays one at a time successively, and a restoring circuit to reenergize the first relay ot' the series.

28. In a signal control system, means for producing two distinct signals, a series of counting relays, an energizing circuit closed for one of said relays in response to the pro duction of one of said signals, an energizing circuit for each of the other relays closed by a preceding relay, means for opening the energizing circuit of said one of said relays in response to the production of the other sigand a locking circuit for each relay controlled by said interrupter.

29. In a train control system, a polarized relay, two contacts, an armature on said polarized relay alternately closing said contacts, a slow-acting relay controlled by each of said contacts, a vehicle, a wheel thereon, an interrupter driven by said wheel, and a set of relays jointly controlled by said slow-acting.

relays and by said interrupter.

30. In a train control system, a travel recording device, a timed means periodically to reset said recording device, a brake, a brake applying means operable by said recording device, a manually operable braking means, and means operable by said braking means to prevent operation of said brake applying means. I

31. In a train control system, a vehicle, a vehicle wheel, a signal receiver, a revolution counter assuming a plurality of successive positions operated by said wheeland reset "at intervals to the starting position by said signal receiver, an automatic braking device for said vehicle operated by said revolution counter when it is in advanced position, and a manual braking device on said vehicle resetting said revolution counter to a position between the starting position and the advanced position mentioned.

32. In a train control system, a track; vehicles on said track; distance measuring means on one of said vehicles comprising a wheel, two control circuits, an interrupter operated by said wheel alternately to open trol system, in combination,

said two control circuits, and a series of normally energized counting relays in two groups-each group being held energized by one of said control circuits, and each individual relay of theseries except the first being additionally held energized by the energized position of an earlier relay of the series; time measuring means comprising means ineluding said track to transmit to said vehicle timed electrical impulses of alternate polarity; receivermeans responsive to the timed impulses; and energizing circuit for the first of said series of counting relays, and hold over means controlled by said time measuring means to maintain closed said energizing circuit during periods of relatively frequent timed impulses and to open said energizing circuit between relatively infrequent timed impulses.

In a continuous indication train control system, in combination, a magnet on the train, means controlled by traflic conditions for energizing and deenergizing said magnet at regular intervals, a circuit controller operated by said magnet, and a train control cir- Y cuit through said circuit controller held closed so long as the interval between successive energizations of said magnet does not exceed a predetermined time.

34. In a continuous indication train cona magnet on the train, means controlled by trafiic conditions for energizing and deenergizing said magnet at regular intervals, a circuit controller operated by said magnet, and a train control circuit through said circuit controller held closed only so long as the interval between successive energization of said magnet does not exceed or fall short of a predetermined time.

35. In a train control system, in combination, a track, a vehicle travelling thereon, a translating device on the vehicle, a timing device on the track, means controlled by said timing device for transmitting electrical impulses through said translating device, a timing device on the vehicle, and indication means under the joint control of said translating device and the timing device on the vehicle.

36. A railway signaling system, comprising a track divided into insulated blocks, means for applying to the rails of a block alternately and periodically two distinctly different electrical currents, and indication means for the blocks controlled by said currents.

37. A railway signaling system comprising a track divided into insulated blocks, means for applying to the rails of the blocks con tinuous current periodically alternating 1n polarity under clear, conditions, means for intermittently applying to a block current of one polarity under caution conditlons, means for intermittently applying to sand block current of the other polarity under danger conditions, and signals for the blocks selectively responsive to said currents.

38. A railway signaling system comprising a track divided into bloc (s, means operating under normal conditions to connect local sources of direct current across the rails of the blocks and to reverse periodically the connections of said sources to the rails, a vehicle having contacts engaging the rails, a polarized relay connected to said contacts having an armature vibrating in unison with the reversals of current in the rails, two slowrelease magnets having circults alternately closed by said armature. and a clear signal having a circuit including front contacts of said magnets.

39. Railway traflic controlling apparatus comprising means for supplying the track rails with energy in the form of spaced groups of impulses, a relay arranged to be energized when-the rails are being supplied with said impulses but to be deenergized between groups, and tr'afiic governing means controlled by said relay.

40. Railway trafiic controllin comprising traffic governing mec amsm on a railway vehicle, a selector on said vehicle for controlling said mechanism, and code impulse transmitting means located in the trackway for controlling said selector.

41. In an automatic train control system, means for communicating an impulse corresponding to trafiic conditions from the trackway to a moving vehicle comprising trackway apparatus for recurrently impressing a predetermined series of time-spaced electrical impulses on trackway conducting means, car-carried means for inductivelyrecciving said impulses, and car-carried apparatus operated synchronously with said trackway apparatus for responding to said impulses.

42. In an automatic train control system, means for communicating influences corresponding to traflic conditions from the trackway to a moving vehicle comprising trackway apparatus, apparatus for recurrently impressing one of a pluralityof predetermined series of time-spaced impulses on the track rails, each of said series of impulses representing certain traflic conditions ahead, means for inductively transmitting said impulses to a moving vehicle, and car-carried means operated synchronously with said trackway means for responding to said impulses.

In witness whereof, I hereunto subscribe my name this third day of January, 1923.

ARTHUR H. ADAMS.

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