US1788880A

US1788880A - Train-control system

Info

Publication number: US1788880A
Application number: US281552A
Authority: US
Inventors: William W Macfarlane
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1914-10-19
Filing date: 1914-10-19
Publication date: 1931-01-13
Anticipated expiration: 1948-01-13

Description

Jan. 13, 1931. w. w. MACFARLANE TRAIN CONTROL SYSTEM Originql Filed Oct. 19, 1914 4 Sheets-Sheet 1 &m

1931- w. w. MACFARLANE 1,788,880

TRAIN CONTROL SYSTEM Original Filed-Oct. 19, 1914 4 Sheets-Sheet 2 3 nve nto'c 1931. w. w. MACFARLANE r 1,783,830

TRAINVCONTROL SYSTEM Original Filed Oct. 19, 1914 4 Sheets-Sheet 3 II HI 'IIIIIHHIIIIllllli Jan. 13, 1931.

WWW

W. W. MACFARLANE TRAIN CONTROL SYSTEM Original Filed 001:. 19, 1914 4 Sheets-Sheet 4 an t m4) venoz Patented Jan. 13,

'wInLIAm w. MACFABLANEOF ELKINS PARK, PEN SYLVANIA; As'sIeNoR; BY iitnsiv n ASSIGNMENTS, TO'THE UNION SWITCH & SIGNAL COMPANY, OF-SW-IssVALEQrENN- v SYLVANIA, A conroaArron orrnnnsytvanmr i 'miinsr-conrnonisys'rnm p Application sled ember-1e, 1914 Sari-341 x931 231E552;1itenewed lilIarch 8,-: 1519.. f

V The present invention relatesgenerallg to traflic controlling devices, and has moreparticularly reference to train controlling sys-. terns. ii

cation'of trah'ic conditions hasusually been given to a train at definite intervals or intermittentlysay at the'beginningof each block The main object and featurefof this invention is to giveacontinuousindication a conductor other thana rail insuch a manner that a signal may begiven or the train rnav be otherwise controlled at. any point in the block through whichIit is traveling.

The advantage of this is that no matter how often traflic conditions "may change, within -a given zone of the train such change will V V p 7 embodiment responsive bothto variations in immediately beindica'ted to the approaching train either by the giving of signals or'by controlling the speed of the train,yorby both.

The train therefore does not have ,Lto wait until it reaches the end of the block before the traflic conditions of other blockscan be as certained. In this mannertraflic' can be hendledwit-h greater safet'y and with less delay. than with an intermitt ent' system of'traflic controL.

In the accompanying drawings andspecification the invention is 'embodied'jin a concrete and preferred form, from which changes may be made Without departing fromthe intended and legitimate scope of the in'ven-f tion as expressed in the a pended claims? of a system embodying thefinvention'.

' Figure 2 is a plan detail view of oneofthe pick up the track currentl contact shoes and adjacent parts used to Figure 351 a sectional view on the line.

38 of Figure 2."

Figure at isasidfe elevation of the parts shown in FigureQ. V

Figure 5 is asectlonal view on the line In the art, as heretofore practiced, an'indi 5:5; ofrigiae s or the translatin dev ce in the, main traflic control circuit.

@hFigure 6 is asectional view on the line 6% 6ofFigure5. 5 f Figure 7 speed controlling devices;

FigureSis 'a side elevation 0f the"speed controlling device shown in Figure 7 with the cover removed.

Figure 9 is a'trans verse sectional viewon the line 9]l9jof Figure 8'.

' Figure 10 is; a tvertical sectional view isa sideielev'ation ofpi e f the through oneof the mercury bulbs the p I wires leadingthereto,"

Figurell is a d'tail view of-oneof the means for operating the 3 speed? controlling device;

S1m1lar characters of referenceindmate' corresponding parts in the several views.

-; ndic tes a translatihg de ice, on the car 2', which is continj ou'sly responsive "to the current flowing through the rails 3 and in this'instance of the trafiic track.

This translating device, is in, its present the characteristic of the current flowing through the'rails as Well-asto the absence of such currentf: The variations in'the current may beproduced in various ways, such as by changing the phase orthe frequency of an To effect this the am; lating ldevice', in its presentembodiment,partakes otthe nature Q'the invention, changing the ofa'polarizedirelay' and constructed as follows:- V V 1 p 5 indicates a magnet havingthe poles 6 and 7 under the influence of which is a polarp p 1 ized armature 8 :controlle'd by springs 9', Figure -1 is a generaldiagrammaticview willlnaturally-take this path inpreference to any other! As here shown, thislowresistmaterial; suchas iron for copper or both,

which sh'oes contact with the rails 3 and 4,:

ance pa-th consists of shoeslOof a suitable I and are carried by slots 11 in a stationary portion of the car 2 and mounted thereon by means of the pins 12, a. spring 13 serving to maintain the contact shoes in engagement with the traihc track. Reaching across the car is a cylinder or other body of copper 14 which is electrically connected to the shoes by means of the copper cables 15. This cylinder. orv bodyiof copper 14c is milled throughout a portion of its length, as shown at 16, with a spiral cut soas to produce a spring or helical-shaped body. Thisbody 14 is further bored longitudinally-as'at 17 and is provided with a core 18 of soft iron insulated from themain body portion 14 by means of the insulating material 19. Each pole 6 and 7, also of soft iron, extends through the side of the body 14 into the core 18 where it is held in position by being in threaded engagement therewith, as shown, and is insulated from the main body portion 14 by means of the insulation bushings 20. This body 14 forms a low resistance path through which the track circuit will easily pass from one rail to the other. 7

Suitable traffic controlling means are controlled by this translating device, which means may be of any suitable character and consists either of signals or of speed controllingdevices or both. For the present, however, it will only be necessary to consider what I shall term the main traffic control circuit of. the train. 1

For the sake of convenience the poles 6 and 7 of the magnet 5.constitute the two terminals of one side of the main trah'ic control circuit which is fed by the battery 21, from which latter extends the conductor 22 which connects to the binding post 23 on the pole 7 which pole is in circuit with the otherpole 6 through the core 18. The other side of the battery 21 is connected to the two terminals 24 and 25, the first one by means of conductor 26, relays 27, conductor 28, and the second one by means of conductor 29, magnets 30 and conductor 31. I

It will be apparent that if a track current of a certain polarity-flows through the low resistance path from one rail to the other,the poles 6 and 7 will be energized and the polarized armature 8 will move "say to cause the terminal 24 to engage the combined pole and contact member 6; lVhen this happens it will be under normal running conditions and current willflow from the battery 21, along conductor 28, coils 27, conductor 26, contact 24,"pole piece 6, binding post23, and con ductor 22 back to battery. If now current of the reverse polarity from thatpreviously considered flows through the low resistance path the poles 6 and 7 will be energized in such a way that the armature 8 will move into position to cause the terminal 25 to engage the combined pole and contact member 7. Current now flows from battery ofrfiat s rin s. 33 from a suitable su )ortin 0 member 3 1, which springs always tend to return the armature 32 to its central position.

Connected to the armature 32 through the medium of the supporting member 34 is a conductor 35 which is connected to one side of the battery 21 through the conductor 22.

36 indicates a conductor leading from the battery 21 which has

parallel branches

37, 38 and 39 terminating in contacts 40, 11 and 42. In these parallel branches are located the signal li hts W, ir and R which respectively indicate white, green and red.

When the coils 27 are energized by current from the battery 21 the armature 32 will be drawn toward the said coils and will close a circuit as follows: from battery 21, through conductor 36, conductor 37 through the light thereof, contact 40, armature 32, conductor 35, through conductor 22, back to battery. So long as the armature 32 remains in its uppermost position this white signal will be given showing safe traffic conditions. If new the. reversal of the polarity of the current through the low resistance path causes. the energization of the coils 30, a circuit would be established as follows: from the battery 21, conductor 36, conductor 38 and the light thereof, contact 42, to armature 32, conductor 35, through conductor 22, back to battery 21. This will display a green light and will indicate thatthe train should proceed under caution. If now no current is flowing through the low resistance path no circuits will be closed and the armature 32 will re main in its mid-position thereby establishing a circuit as follows: from battery 21, conductor 36, conductor 39 and the light thereof, contact 41, armature. 32, conductor 35. conductor 22, back to battery 21. T his will display a red light which indicates a danger condition. Having now observed the eiiect of currents of different polarity and of the absence of current upon the low resistance path and its translating device and the effect thereof upon the main trailic controlling circuit, I now proceedto describe the means whereby the characteristic'of the current in the track may be varied or whereby current may be cut off altogether.-

The rails 3 and 4 are divided by insulation 43 in a well-known manner so as to produce teries are arrangedto provide-the usual low" voltage current to thet-rackrail'bircuit 'but differ from the ordinary track batteries heretofore known in that they'arearranged tofurnish a current of comparatively large volume Whereas the volume of'current furnished by the usual traclfbatteryis comparw tivcly small;

The track circuit is. normally completed 'through conductors 55 and 53 leadingfrom the track battery to relays-54a, 54b, etc.,fas the case may be. The coil of each'relayf54 is given such a: resistance value that, combined With a low resistance element X, that is preferablyincluded-in the conductor 45, the cur rent flowing through the track circuitivhen a train'is not intheblock ivillhavo very little tendency either to leak through tlieirail insu-i lation or'to exhaust the battery. 1 l A small'batteiy 63 preferably arranged to furnish both'a low voltage an'd asinall vol ume of'current is also connectedto the track rails throughthe conductors 68and'64. Con

du'ctors 67, 66 and: lead from the rails at the opposite end of the block and include the relay coil 62. This battery'ca'nnot furnish any current that will have anyeffe-ct on the train controlling device: a 7

- Normally when 'a'train is not'present in aa biocl: the battery i energizes. the relay coil 54. of the block to the rear through the track circuit already traced. The armature '51 of the relay acts as" a pole changerfand in the energized condition "of the relay coil thecurrent flows through the track circuitin a direction to flow "across'irom say rail 3 to rail i' rear, it will benoted that relaycoilii ib of block B is shortcirc-uited by the presence of the tram in block C, the'current flowing from n battery 440 through conductors' 58 and 57",

armature 51, conductors 61 and 56,1'ail- 8, low

resistance path 5, rail 4, conductor 52,,ermature 51, conductors 50,4i8; and 45 ba'clrto battery, instead of flowing through theconductor 55, thecomparativelyhigh resistance 5%,

and'the conductor 53;- The efi' ect of deenergizing relay 54bit to reverse thep'ole-- changer 51 through which batteryA'lb'is'connected to therail's 3' and 4 of block B.

. The presence of the train-in block C also short circuits relay 626, which is controlled light until traiiic 7 conditions change train shouldenter the block immediately beterrupts the track circuithof block B and deen'ergizes'ithe relay coil 54a of block A to reversethe flow of current through the rails ofthat block. K

.ductors48 and 50 at the break 49. This in In addition' to the connectionsiofthe batterie s Mmfabretc. tothe rails'oi? the block sections already referred to, these batteries are also connected to thef'railsof the blocks immediately in advance through the conduc-f tors 59 and 67 on the one handjiind conduc= 'tors45, magnet-69 andconductor-65 on the p b p other, with this arrangement the b ttery 446 the track; rails at the end'o-f the'block opposite o'fblocl; B energizes the magnet 69?), flowing across the a'xlesoi the train block C to-comple-te a 'circuit. The energization of magnet 69b opens the circuit through"conductors45 and 48 at the point i? thus providing a seccircuit ofbloc-k A. Also thebattery'd'a,

since there is notrain in' bljockB, can no longer "energize relay 69o so that the second break at 47 in the trackcircuit'oi block A is closed: z

The magnet 69b is arranged to provide a relatively high resistance so" that the current flowing through the trainaxles circuit with the magnet 69Will haveno'efiect on the controlling devices carried by the train." It is also to be noted that the two'magn'ets'62 and 69 hich are arrangedin series in 'thc cir'cuits'59, 66, 45 andj i iaregiven such resistance values in relation to the batteryl that they are unaffected-by this battery.

Thusit will be seen that the track circuit of the block immediately inthe rear of a trainoccupied block is interrupted so that'a train entering suchblock ivould'fail to pick up current-land would best-ripped while the sec 0nd block in the rear of a train-occupied block Will have its trackcircuit reversed to display.

a caution signal in the cab of a train entering such block, I I V i From the foregoing; it will observed that ihen'a train is traveling through a block,

current in a certain direction will 'pass through the low resistancepath of the'car and will maintain a continuous White lightin the cab in the manner previously. described. Should noWanother train approach within the blocks of the first train; it will encounter a reverse-flow of currentin the manner. described and will consequently receive a green If a hind one occupied by another car,.-no current flowing in said block immediately behind the. other car, the red'signal Will be given in the main trafiic controlling circuit in the manner described.

' .Vhile there is no current from the battery 44 present in the rails of the section immediatolybehin d the one occupied by a car, it will be noted that current still lo-wing in this section from the auxiliary battery 63 in order to maintain the contact 49 closed in the next succeeding block.

It is pointed ou that the resistance of the magnet 54 is such, that in addition to preventingthe energization of the magnets 62 and by the battery 44, the energization of the magnet 69 and the magnet 54 of the bloclrin advance through the

circuit

45, 69, 65, 55, 53, 67, 59 is also prevented.

As has already been pointed out, the relay 54 together with the small resistance X have such a value in relation to the battery 44 that a current of very small volume flows through the track circuitin a block when a train is not present. The shunting out of the comparatively high resistance relay 54 by the entrance of a train into a block under safety or caution conditions immediately renders available a current sufficiently large in volume to insure the operation of the train-carried controlling device. At the same time the retention of the low resistance X in the circuit prevents such an undue volume of current to flow as would injure the battery.

The shoes 10 are preferably located on the car between the pony trucks, and if desired the axles in advance of such shoes can be insulated between parallel rails so that no current can pass across from one rail to the other through said axles. The resistance of the body 14 is very low. say one-fifth of the resistance of the two wheels at the point of contact with the rail and the axle connecting the same. Or to state it differently the resistance of the body 14 is about the same as the resistance of about fifteen feet of un bonded rail lbs. It may therefore not be necessary to provide insulation between the opposite wheels.

100 indicates the train line controlled by the valve 101 which when opened will. cause a suflicient reduction in the train line to give a service application. of the brakes. The stem i bifurcated arm 105 pivoted at 106 and having an abutment member 107. A spring. not shown. inside the valve will normally tend to raise the valve stem 102 into its uppermost position. 108 indicates an actuating member mounted on the shaft 109 and normally held out of engagement with the abutment member 107 by means of the coiled spring 110 which presses said actuating member 108 home against the stop 111. Mounted to move with this actuating member 108 is a ratchet 112 adapted under-certain conditions to be actuated by the pawl 113 mounted on the cocentric 114 and having an extension 115 forming an armature for the magnet 116. 117 indicates a back pawl pivoted at 118 and having also an. extension 119 which forms an a rmature for the magnet 120. The pawl 11'? also carries a circuit closer 121 which controls a circuit to be presently described, for energizing the magnet 110. The eccentric 114 is continuously driven by suitable transmission from the axle 122 of the car such as the gears 123 and flexible shaft 124. The flexible shaft 124 is connected fast to the casing 125, which casing carries a pawl 126 that engages with a ratchet 12? fast on the shaft 128 on which the eccentric 114 is mounted. The pawl 129 is a stop pawl to prevent the ratchet from reversing.

It will be observed that the pawl 113 is constantly actuated so long as the train is moving but is normally prevented from engaging the ratchet 112 by reason of its extension 115 which remains in sliding contact with the magnet 116. eimilarly the back pawl 11'? is normally out of engagement with the ratchet 112. hen, however, these two magnets 116 and become deenergized the pawl 113 drops by gravity into engagement with the teeth of the ratchet 112, as does the pawl 117, and the rotation of the shaft 128 and the eccentric 114 will therefore feed the ratchet wheel 112 forward intermittently in one direction acting against the opposition of the spring 110. The ratchet 112 will carry the actuating member 108 with it until it engages the abutment member 107 and opens the valve 101.

Driven from the shaft 128 is a speed governing device in the form of a rotatable bulb of a fragile material as glass. containing mercury and forming in connection with the requisite conductors a circuit closer and opener: As here shown the shaft 128 carries a large bevel gear 130 which engages with a bevel pinion 131 carried by the hollow shaft 132 and its connecting wires. The mercury bulb 133 may be variously shaped, its shape depending upon the amount of displacement of the mercury desired at certain speeds of rotation. Dipping into the mercury contained in the bulb 133 are conductors. as shown more particularly in Figure 10, which pass up through the interior of the shaft 132. being suitably insulated from each other as shown.

lVhen trafiic conditions are safe and a white light is showing in the cab, the armature 32, as previously described, will be attracted by the relays 27. In these circumstances a circuit as follows is established through the coil of the magnet 120 from battery 21, to wire 134, conductor 200, to binding post 81 and thence to coil 120. by means of conductor 135, thence by conductor 136, to

binding post 80, thence by conductor137 and conductor 188ito contact 139, armature 32, conductor 35, conductor 22, 1battery'21, if nowa green light isldisplayed in the cab and the. armature 32 isattracted by the coils 30, then a circnit as follows Will be established from battery 21, along wire 134, conductor" 200,tobinding post 81, to coil 120, to bindwill drop into engagement with the ratchet' j 112 and its circuit closerv 121 will be moved out oficontactvvith'thepoints 14:7 andfliS, thereby destroying, the following circuit through the magnethl lti; from bindingapost 81, by Way-of conductor 149 through coil116,

' through; conductor 150, contact- 1 17 circuit closer 1211, contact 148, conductor 151 to binding post The rupturing of this circuit and the 'deenergization ofthe magnet 116 will cause, thepaWl113 to engage with the ratchet-1l2'and thus cause a reductionuin the speed is I above" a predetermined" amount the V mercury Will have'inoved awayfromthe contact-s 158 and'154 andsthllsthe magnet 120V safetrafiic conditions. H

train line by the means previously described, If a redsignalisjgiven inrthe'cab then the armature 32 :Will be in thefmiddle f-p'ositio'n and the follon ing'circuit will then be. es-, tablished: battery 21, along conductor 134, conductor 200, to binding post 18-1, inagnet 120,- binding post 80, conductor l52, to con" tact 153, mercury 1 12, contact 15 1, conduc-r tor 155, to battery 21, ln-case, however, the

would: bedeenergized lith the result previously described. I .v \Vhat isclaimed 1s: 1

1.; A system of train control comprisin traflie rails, a track 0111311113111 said :r'ails aresponsive to'sate and unsafe conditions, means on the train:- including 7 an electro-responsive devicegadapted toshOrt-circuit, 'aitrain. axle and its attached Wheels and respond to the r 7 condition ofthe circuit insaidlrails and tending to apply the brakes 'underfunsafecondioperation ofthe brake applyingmeansundef; certain speed COIldllllOIlS, and means for pre--' .1 "venting the operation of the brake applying;

means by the speed controlledmeans when the "condition of the track: circuit indicates p 2. A traffic'controlling device c0mprising:

pair'ot train-carried current collecting thelelectrical condi on-0f s i r s- $hQesarranged1tomake sliding on ac or asubstantial surfaceareaeach with adifierent one of the trafiic r ails ,;;a conductor connecting said shoes and, havingiadegree ofelectrical. conductivity relatively high n thatpf a train, axle,;said conductor forming a t l.cioil ffand an electro responsive devicev including said cell as a part thereof, vsaid eleca troy-responsive, device. operating 1 to indicate 7 '1 34A traific controlling device comprising:

a pain-got train-carried current collecting shoeslarranged to make sliding contact with the :Vtraflic rails,--a condu ctpr connecting said shoes and extending across the train closely adjacent the level ofsaid shoes, said conductor forming, a coil,- :and an electro-responsive deviceincludingsaid coilas a partthereof, said-.1electro-responsive device operating to indicate the electrical condition Qtsaid rails. 1 4.1 A 'traific controlling device comprising:

aqpai-r, of train-carried; current collecting V shoes arranged tomakesliding contact forv a substantial surface area each with a difiersent, o11e'of"the traflic rails, a conductor .con-

necti'ng said shoes ,and havinga degree of electrical,conductivityjrelatively higher than; that-of a-"train axle-and extending across the train {closely adjacent the level ofsaid shoes, said conductor forming a coil, and an electrorespo'r isive device including saidjcoil as ;a,

part: thereof, said electro-responsive device operating to ind cate the electrical condition ofsaid rails. I

v -5.= A{traiiic, controlling device afpair; of train-carried 7 current collecting members arranged-to make contact with the, traffic rails, a'conducting bar extending across 1 theitraimlcondnctors connecting the ends of" said .bar to said members, a portion of said bar havinga coil formation, and an ,electroresponslve device lncludlng said C011 and operating .to indicate the electrical condition ofsa'idrails. ia I A I traiiic controlling device comprising a-pairoftrain-carried current collecting; members arranged'to make contact'with the "traflic rails, afbar havingqagdegree of electrical conductivityrelatively" higher than; that of'a train. axle and extending across the train, conductors connectingthe ends of said bar'to saidmembers',-aportionof said bar having a helical, formation of comparatively L device including, said coil :and operating to p V v indicate th'elelectrica'l condition ,ofsaid rails. tions, speed controlled means'forca'uslng the-u 7. A traffic controlling device -comprising: a: pair of train-carried currentI collecting shoes; arranged toimake sliding contact for a substantial area of engagement with the.

loo

large. cross section, and, an eleCtro-responsive the ends qfasaid memberto, said shoes, aporizo 'trafiic rails, a conductinglm'ember ihavinga I degree of electrlcal ,conductivlty relatively tion of said member having-a coil formation of strip-sliaped turns with a comparatively large cross-section, and an electro-responsive device including said coil and operating to indicate the electrical condition-of said rails.

8. A traffic controlling device comprising: a pair of train-carried current collecting shoes arranged to make sliding contact for a substantial area of engagement with the traffic rails, a bar having a degree of electrical conductivity relatively higher than that of a train axle and extending across the train adjacent the level of said shoes, flexible cables also having a higher degree of electrical conductivity than that of a train axle connecting said bar to said shoes, a portion of said bar having a relatively massive coil formation, and an electro-responsive device including' said coil and operating to indicate the electrical condition of said rails.

9. A- traflic controlling device comprising: a pair of train-carried current collect ng shoes arranged to make sliding contact w th the traiiic rails, an electro-responsive device including an elongated energizing coil formed of a strip-shaped conductor extending transversely of the train ad acent the level of said shoes, and flexible cables connecting each end of thecoil with points adjacent the rear and the forward ends of the corresponding shoes, said shoes, said coil and said conducting cables having a substantially higher degree of electrical conductivity than that of a train axle.

10. A traflic controllingdevice comprising: a pair of train-carried current collecting members arranged to make contact with the traffic rails, and electro-responsive, device having a coil formed of a metal strip theadjacent convolutions of which are separated by a substantial air gap, a core of magnetic material in said coil, and conductors connecting the ends of said coil to said shoes.

11. A traffic controlling device comprising: a pair of train carried current collecting members arranged to make contact with the traflic rails, an electro-responsive device having a cylindrical coil formed by a metal strip having a substantial cross-section, a core of magnetic material in's'aid coil, and conductors connecting the ends of said coil to said current collecting members, said members, said conductors and said coil having a degree of'electrical conductivity sufficient to short-circuit the rail-bridging connection formed by a train axle and its attachedwheels. Y

l2. Atrafiic controlling device comprising: a pair of-train-carried current collecting shoes arranged to make sliding contact with the traffic rails, devices for causing the movement of the shoes along the rails with the train but permittingvertical movement of the shoes in relation to the train, a conducting member extending transversely of the train, a. portion of; said'member having a coil formation, a plurality of flexible conductors connecting each end of the conducting member to separated points in the corresponding shoe, and an electro-responsive device including the coil portion of said member and operating to indicate the electrical condition of said trariic rails.

13. In an automatic train control system for protecting railway traific, in combination a railway vehicle and a track therefor; permissive speed means on the vehicle adapted to be changed to establish several permissive speed limits for the vehicle; and means comprising elements on the vehicle and along the track arranged in electrical co-operative relation for changing said permissive speed means to a variable degree at control points along the track in accordance with the extent of unoccupied track in advance of the vehicle.

14. In'an automatic train control system for protecting railway ti"af"nc,-in combination a railroad track provided with normally closed track circuits for detecting the presence of trains at dilferent places along the track; a vehicle and automatic train control apparatus therefor operable under varying influences to automatically enforce correspondingly different limitations on the speed of the vehicle, and means governed by said track circuits for establishing electrical communication with said vehicle and for influencing said train control apparatus to a vari able degree in accordance with the nuinbe' of'unoccupied track circuits in advance of the vehicle.

15. In a system for automatically protecting traiiic on railroad tracks, the combination with automatic mechanism on a vehicle adapted to assume distinctive conditions to establish any one of a plurality of permissive speeds for the vehicle, said mechanism having a tendency to assume its lowest speed condition, of means comprising elements along the track responsive tothe presence of trains thereon and co-operating with elements on the vehicle for varying the condition of said mechanism in opposition to said tendency and substantially in accordance with the extent of unoccupied track in advance of the vehicle.

16. In an automatic train control system, the combination 'Witha vehicle, of a permissive speed device on the vehicle normally tending to assumeits lowest speed condition, a circuit andcontrol means on the vehicle responsive to electrical energy of varying characteristics for influencing said permissive speed device to higher speed conditions, and'means along the trackway for producing varying characteristics of electrical energy in said circuit of, a passing vehicle at control points along the track.

17. In an automatic train control system, the combination with a vehicle, of automatic train control apparatus therefor adapted to enforce automatically anyone of plurality of continuing limitation "on its speed, said apparatus having an automatic tendency to assume its lowest speed condition, impulse receiving means-on the vehicle, and means including trackway apparatus and circuits responsive to. the presence of a train and co circuit for-energizing said device having a plurality of branches in'niultip'le, speed-responsive means governed inaccordance Wltll the actual speed of the veliicle for selectively the vehicle' controlling said multiplebranch'es, permis-. sive speed means for selectively controlling said multiple branches in accordancewith the safe permissible speed for the vehicle, said permissive speed-meansbeing responsive to predetermined variations-in the character of electrical energy. supplied thereto; tr ckway means for normally supplying electrical energy to the permissive speed means on a vehicle during its progress' through a block, said trackway means acting to vary the char acter of saidenergy to conform withfthe number of unoccupied blocks in advance or" 19. In an automatic traincontrol system for railroads divided intoblo'ckseach provided w th a normally closed track circuit;

the combination with automatic 'ti aincontrol apparatus on a vehicle including electroresponsivejpermissive speed means tending to'changeto'warcl itsminimum speed conditioii, and brake control means ii'or' automatically applying the brakeswhen the actual speedof the vehicle 'eXce'eds'ti-iat prescribed by said permissive speed means,"or" means partlyon the vehicle and partly along'the track for normally supplying "electrical energy of different characteristicsto said per missive speed means varying in accordance with the number of blocks in advance ofthe vehicle which are unoccupied;

20. In combination, a ra1 comprising "a speed controlled part and a speed limit part, electrical means governed by the polarity of current supplied'ithereto for controlling said speed'limit part on the vehicle; electrlcal means along the trackway co-operating with saidth-ird mention 'lmeans to :cause currents of different polarity} to be tssupplied thereto;

-' 21 combination, a railway vehicle;

vehicle controlling means thereon, means for controlling said vehicle controlling ,means comprising a speed controlled part and a speed 'ilimit part; electrical means governed by the polarity of current supplied thereto for controlling said speed limit vpart on the vehicle; electrical means "along. the trackw'ay co operating gwith said third mentioned means'to cause currents of diflierentpolarity to be supplied thereto and signals ;on the 7 vehicle indicating the controlpfsaid' spee'd 7 limit device effected I I 22. In an automatic train control system for protecting railway trafi'io, in combination: a railroad track-provided with normally closed traclrcircuits for detecting the'pres ence of trains 'atdiflt'erent place'salong the track; a vehicle and automatic train control apparatus theretorioperable under varying influences to automatically enforce correspondingly different limitations on the speed of the vehicle, and means substantially contiuuously governed bysaid track circuits for establishing; substantially all points along the track,felectrical communication with said vehicle and for substantially continuously in fluencing said train control apparatus to a variable degree in accordancewith the num; her of unoccupied track circuits inadva-nce v of the vehicle. p

23. A system for automatically protecting trailic on railroad tracks includingz a trafiic track composed of traflic rails and arranged in blocks, a car traveling onthe track; and an automatic device on the car,=substantially ccntinuously responsive to variations in the influence of current flowing in the traflic rails of the blockthrough'which the car is traveling, to impose, in response to a change in tr'aific conditions and at substantially any point within a block that one of a pluralityof permissive speeds on the car permissible under the particular conditions.

241A system for automatically protecting I traflic on railroad tracks including; a'traflic trackcomposed oi tratfic'rails and arranged in blocks, a car traveling on the track, and an in pairt electro-inagneti'c automatic device on the car, substantially continuously respon sive to'va'riati'ons in the influence of current flowing int-he trafiic'railsof the block through which the car is travelin togim ose in re- 7 sponse to a change in trafiic conditions and at lway vehicle, vehicle controlling means thereon, means for controlling said vehicle controlling means substantially any point within a-block, that one of a plurality ofpermissive speeds on the car: permissible under the particular condi-V in blocks, a cartraveling on thetrack, and:

automatic means on the car, including an actual speed device and a brake'settingfde "vice, substantially continuously- -responsive ill to variations in the influence of current flowing in the traflic rails of a block through which the car is traveling, to impose, in re sponse to a change in traflic conditions and at substantially any point within a block, that one of a plurality of permissive speeds on the car permissible under the particular conditions.

26. A system for automatically protecting traflic on railroad tracks including: a trailic track composed of traflic rails and arranged in blocks, a car traveling on the track, and automatic means, in part electro-magnetic, on the car, including an actual speed device and a brake setting device, substantially con tinuously responsive to variations in the influence of current flowing in the traflic rails of a block through which the .car is traveling, to impose, in response to a change in traflic conditions and at substantially any point within a block, that one of a plurality of permissive speeds on the car permissible under the particular conditions.

27. A system for automatically protecting trafiic on railroad tracks including a traflic track composed of traflic rails and arranged in blocks, a car traveling on the track, and an automatic device on the car, substantially continuously responsive to variations in the influence of current flowing in the tratfic rails of the block through which the car is traveling, to impose, in response to successive adverse changes in traflic conditions and at substantially any point within a block, successively lower permissive speeds on the car.

28. A system for automatically protecting traiiic on railroad tracks including: a traffic track composed of traflic rails and arranged in blocks, a car traveling on the track, and an in part electro-magnetic automatic device on the car, substantially continuously responsive to variations in the influence of current flowing in the traflic rails of the block through which the car is traveling, to impose, in response to successive adverse changes in trafiic conditions and at substantially any point within a block, successively lower permissive speeds on the car.

29. A system for automatically protecting traflic on railroad tracks including: a traffic track composed of traflic rails and arranged in blocks, a car traveling on the track, and automatic means on the car, including an actual speed device and a brake setting device, substantially continuously responsive to variations in the influence of current flowing in the trafiic rails of the block through which the car is traveling, to impose, in response to successive adverse changes in traffic conditions and at substantially any point within a block, successively lower permissive speeds on the car.

30. A system for automatically protecting traflic on railroad tracks including: a traflic track composed of traffic rails and arranged in blocks, a car traveling on the track, and in part electro-magnetic automatic means on the car, including an actual speed device and a brake setting device, substantially continuously responsive to variations in the influence of current flowing in the traffic rails of the block through which the car is traveling, to impose, in response to successive adverse changes in traflic conditions and at substantially any point within a block, successively lower permissive speeds on the car.

31. A system for automatically protecting traflic on railroad tracks including: a traflic track composed of traflic rails and arranged in blocks, a car traveling on the track, and automatic means on the car, including an actual speed device and a brake setting device, substantially continuously responsive to variations in the influence of current flowing in the traffic rails of the block through which the car is traveling, to determine, in response to favorable or adverse changes in traflic conditions and at substantially any point within a block, that one of a plurality of permissive speeds permissible under the particular conditions. 1

32. A system for automatically protect ng traltic on railroad tracks including; a traflic track composed of trafiic rails and arranged in blocks, a car traveling'on the track, and automatic means, in part electroanagnetic, on the car, including an actual speed device and a brake-setting device, substantially continuously responsive to variations in the influence of current flowing in the traflic rails of the block through which the car is traveling, to determine, in response to favorable or adverse changes in traflic conditions and at substantially any point within a block, that one of a plurality of permissive speeds permissible under the particular conditions.

33. A system for automatically protecting traflic on railroad tracks including: a trailic track composed of traflic rails and arranged in blocks, a car traveling on the track, an automatic device on the car, substantially continuously responsive to variations in the influence of current flowing in the traflic rails of the block through which the car is traveling, to impose, in response to a change in traflic conditions and at substantially any point within a block, that one of a plurality of permissive speeds on the car permissible under the particular conditions, and a track circuit controlling the flow of current in the traflic rails of a block, and substantially continuously responsive to traflic conditions of another block, acting through the medium of the traflic rails to control the automatic device on the car.

34. A system for automatically protect ng traffic on railroad tracks including: a traflic track composed of traflic rails and arranged in blocks, a car traveling on the track, an in part electro-magnetic automatic device on 41. A system for automatically protecting trafiic on railroad tracks including: a traffic track composed of traflic rails and arranged in blocks, a car traveling on the track, automatic means onthe car, includin an actual 7 to favorable or adverse changes in traflic conditions and at substantially any point within a block, that one of a plurality of permissive speeds permissible under the particular conditions, and a track circuitcontrolling the flow of current in the trafiic rails of a block, and substantially continuously responsive to traffie conditions of another block, acting through the medium of the traiiicrail's to control the automaticmeans on the car.

42. A system for automatically protecting trafiic on railroad tracks including: a traffic track composed of traflic rails and arranged in blocks, a car traveling on the track, automatic means, in part electro-magnetic, on the car, including an actual speed device and a brake setting device, substantially continuously responsive to variations in the influence of current flowing in the traflic rails of the block through which the car is traveling, to determine, in response to favorable or adverse changes in traffic conditions and at substantially any point within a block, that one of a plurality of permissive speeds permissible underthe particular conditions, and a track circuit controlling the flow ofcurrent in the traflic rails of a block, and substantially continuously responsive to traffic conditions of another block, acting through the medium of the traffic rails to control the automatic means on the car.

43. A systemoi' train controlcomprising: traflic rails divided by insulation into conducting blocks, a source of electric energy connecting therails of each block, a train, electro-responsive train controlling means on said train in shunt with said traffic rails, means for controlling the circuit in one block from another block to apply the brakes on a train traveling in said first-named block, means for automatically releasing the brakes to permit the train to proceed at a predetermined speed, means for controlling the circuit in said train-occupied block from a third block to'apply the brakes on said train, and means for automatically releasing the brakes to, permit the train to proceed at a different speed. 7 i

44. A system of train control comprising: trafiic rails, a track circuitin said. rails, a vehicle, controlling means on said vehicle constructed and arranged to be placed in shunt with the track circuit and to short oircuitt-he adjacent wheels and axles, speed controlled means, means for aflecting said circuit to operate said controlling means when the vehicle is traveling at a certain speed, and means cooperating with said speed controlled means for affecting said circuit to operate said controlling means when the vehicle is traveling at a different speed.

45. Asystem of train control comprising;

'trafic rails divided by insulation into conducting blocks, a source of electric energy connecting the rails of each block, a resistance also connecting the rails of each block whereby a current of small volume normally flows in said block circuit, a train, elect-roresponsive train controlling means on said train bridging said traiiic rails and having a comparatively low resistance whereby a current of large volume flows through said train controlling means, speed controlled means, and means for controllin the circuit in one block from another block and cooperating withthe speed controlled means'to reduce the speed oi atrain traveling in said first-named block.

46. A system of train control comprising: traiiic rails divided by insulation into conducting blocks, a source of electric energy connecting the-rails of each block, a resistance also connecting the rails of each block whereby a current of small volume normally flows in said block circuit, a train, electro-responsive train controlling means on said train bridging said trafiic rails and having a comparatively low resistance whereby a current of large volume flows through said train controlled means, speed controlled means, and means for controlling the circuit in one block from another block cooperating with said speed controlled means to automatically increase the speed of a train traveling in said first-named block. 7

47. A system of train control comp-rising: traificrails divided by insulation into conducting blocks, a source of electric energy connecting the rails of each block, a resistance also connecting the rails of each block whereby acurrent of small volume normally flows in said block circuit, a-train, electro-responsive train controlling means on said train bridging said traflic rails and having a comparatively low resistance whereby a current of large volume flows through said train controlling means, speed controlled means, and means for controlling the circuit in one block,

from, another block cooperating with said speed controlledmeans to automatically decrease or increase the speed of a train traveling in said first-named block.

48. A system of train control comprising: traffic rails divided by insulation into conducting 1bl ocks,a source of electriclenergy connecting the rails of each block, a train,

electro-responsive train controlling means on said train in shunt with said traflic rails, means for controlling the circuit in one block from another block to apply the brakes on sage) a traveling in said first-named block, n

means for automatically releasing the brakes to 'perinit the trainto proceed at a predetermined speed; means for controlling the different predetermined'speed.

ducting blocks, a source of electric energy connecting the rails of each block, a resistance also connecting the rails of each block -w b a current of small volume normally flows in said block cir'ouit, ja train,:electroresponsive train controll ng meanson sa1d train in shuntwith 'saicl traflic rails'and having a comparatively lovvl resistance whereby a current V of large volu ne flows through; sa d n1eans,'and-means for controlling the circuit in one block frorn'another block cooperat-' ing with said speed controlled means to 0p,-

erateisaid train controllingrneans when the trainis traveling'at a certainspeed;

50. A vsystenr of train. control comprising trafilcfrails, divided by insulation into conductingfblocks', a sourcegof electrioenergy connecting the rails of each block, a"'tra in', electro -responsive train controlling means on said train in shunt with said traflic railsijj speed controlled means, means' "for controlling the circuit in onejblock'froni another; block and cooperating "with said-speed con-1 trolled means to operate said train Co nor, ling means when the train is traveling at "a j certain'speed, and means for controlling the] circuit infsaid' train1 occupiecl block from a third block land cooperating with said; speed controlled lneansito operate saidftr'ain conthe trainlis traveling at trolling-means when a difierent speed.

v 51'. A system for automaticallyprotecting traffic on railroad tracks including'r' a 'trafiic track composed of traffic rails and arranged in lblocks', a car traveling onthetrackf track a circuit means-[associated*vvithieaoh,lolook to; "supply flow" of cur'rentjo the trafiic'iraiis of.)

bloclnltranslatingmeans substantially eta-i tinuously responsive to the influence, of our 7 rentfl'ovv in the rails of afbl ockjto'vary; When"v a change traffic, conditions o fi'one nieansof another block andautomatic means on the car to'impose o'njth'e car-different speed car is traveling, anactualfspeedf device sub} stantially continuously responsi e-a0 the speed of the; car, andhrakesetting ineans I "substantially continuously responsive to the 49. A. system of train jcontro'l comprising trafiic rails"divided by -insulation into eon,

c "53, A'systeInforF speed" devices 52; A systern for automatically"protecting in blocks, acar traveling on the'traok, track traflicon railroad: tracks including: a traffic. track composed of'trafiic rails and arranged circuit Insane associated with each block to upply flow of "current to the "traffic rails? of a block, translating niean's substantially con 'tin'uou'sly responsive to the'infiuence of curjrent flow in the rails of'ablock to vary, when a change in traffic conditions of onefbloclt occurs, thednflue'noebf the track circuit? meansof another block, and automatic ne'ans v v on the car to impose onthecar different speed limits in'response to difierent trafiic'coindb tions including translating nieans on the car substantially continuously] responsive to vari'ations in the influence "of current flowiin V v '{the trafiic rails of theblock through'vvhich train controlling means speed controlled; the car-is traveling,a permissive sp'eed'device [substantially continuously." responsive to the car carried translating means, an actual speed 7 Y device" 'substantiallycontinuously responsive tothe'speed 'ofthej car, andibr ake setting means substantially continuously responsiVQ l to the joint control of the"permissivefand actual speeddevices.- j

trackcomposed of"traiiic"rails and arranged await-anyaaeaag traffic on railroadftracks' including a tralfic in blocks; a. car traveling on the track, a per- 'jfmi'ssive speed device on the car substantially continuously responsive to variations in the influence of current flow in the traffic rails of ,theiblockthrough'vvhichthe car: traveling V to thereby establish different speed conta n monliinits,j"an actual speedfdevice also on the earl substantially continuously responsive to the? ;speed ofthe car to thereby assume different speed control conditions, a brake setting imeans on tliev car substantially continuously responsiveto the joint control ofthe perrnis sive andactual speed devices, and'atifackcirc cuitf controlling the 1 flow of current in the traflic rails of a block, substantially con-"2 tinuously responsive totrafiic conditions of the traificrails tojco'ntrol device on that,

inb ocks, a. car travelling on the track,'a permissive" speed device on thecar; substantially V I p ,1 co tmuously responsiveto variations n the] linnits {in response to different traffic" condi .anothrblock, acting throughthe of the p'erinis'sive speed r q i v V 54. A' system forfautoniatieally protecting influence of current flow in thetrafiicrails of j' h Q Q't i ghWh Qh h be' i ftra e i tof'the'reby'i establish difierent "speedj control 1irnits an actual-speed device alsoon the car missive and actual speed devices, track circuit means associated with each block to supply flow of current to the traffic rails of a block,

55. A system for automatically protecting traflic on railroad tracks including: a traflic track composed of traffic rails and arranged in blocks, a car traveling on the track, track circuit means associated with each block to supply flow of current to the traflic rails of a block, translating means substantially continuously responsive to the influence of current flow in the rails of a block to vary, when a change in traiflc conditions of one block occurs, the influence of the track circuit means of another block, translating means on the car substantially continuously responsive to variations in the influence of current flow in the traflic rails of the block through which the car is traveling, a permissive speed device substantially continuously responsive to the car carriedtranslating means to thereby establish different speed control limits, an actual speed device also on the car substantially continuously responsive to the speed of'the car to thereby assume different speed control conditions, and a brake setting means on the car substantially continuously responsive to the joint control of the permissive and actual 1 speed devices. I

56. A system for automatically protecting traflic on railroad tracks including: a traflic track composed of traflic rails and arranged in blocks, a track circuit completed through the traific rails of a' block and responsive to traflic conditions for supplying across the traffic railsat the exit end of the block a car governing current, a car traveling on the track, automatic means on the car, substan-. tlally continuously responsive to VZLIIatlOIIS in the influence of the car governing current flowing in the trafl'ic rails of the block through V which the caris traveling, including: a signaling device and a brake-setting device, and

-;me'ans on the car to annul the influence exercised over the brake-setting device without annulling the influence exercised over the signaling device. 7 v

57 A system for automatically protecting traffic on railroad tracks including: a traflic track composed of traflic rails and arranged in blocks, a track circuitcompleted through the traflic rails of a block and responsive to traffic conditions for supplying across the traffic rails. at the exit end of the block a car governing current, a car traveling on the track, automatic means on thecar, substantially continuously responsive to variations in the influence of the car governing current fl'owing in the trafiic' rails of the block through which the car is traveling, including: a signaling device and a brake-setting device, and means on the car to annul, under adverse traffic conditions, the influence exercised over the brake-setting device without annulling the influence exercised over the signaling device.

58. A system for automatically protecting traflic on railroad tracks including: a traflic track composed of traflic rails and arranged in blocks, a track circuit completed through the traflic rails of a block and responsive to trailic conditions for supplying across the traflic rails at the exit. end of the block a car governing current, a car traveling on the track, automatic means on the car, substantially continuously responsive to variations in the influence of the car governing current flowing in the traffic rails of the block through which the car is traveling, including: a signaling device and a brake-setting device, and an actual speed device on the car to annul the influence exercised over the brake-setting device without annulling the influence exercised over the signaling device.

59. A system for automatically protecting traflic on railroad tracks including: a traflic track composed of traflic rails and arranged in blocks, a track circuit completed through the traflic rails of ablock and responsive to traffic conditions for supplying across the traiflc rails at the exit end of the block a car governing current, a car traveling on the track, automatic means on the car, substantially continuously responsive to variations in the influence of the car governing current flowing in the traffic rails of the block through which the car is traveling, including a signaling device and a brake-setting device, and an actual speed device on the car to annul, under adverse traflic conditions, the influence exercised over the brake-setting device without annulling the influence exercised over the signaling device.

60. A system for automatically protecting traflic on railroad tracks including: a traflic track composed of tratflc rails and arranged in blocks, a track circuit for each block including the traflic rails of the block and one current source, a second track circuit for each block including the trafiic rails of theblock and a second current source to be connected across the traflic rails at the exit end of the block, means controlled by the first track circuit to connect the second source of another block to the rails of said other block,

traflic controlled means to reverse the c011- nections between said second source and the rails, a car traveling on the track, and carcarried apparatus continuously responsive to.

variations inthe influence of current from the second source flowing in the rails of-the block through which the car is traveling.

61. A system for automatically protecting traflic on railroad tracks including: a traffic track composed of traffic railsand arranged in blocks, track waycircuit means for each 7 block including :a ;trackway source 7 of at the exit endof a'block,3a car traveling'on the track, automatic means, including a brake-setting device, 911; the car substantially continuously responsiveto the influence of an actual speed device on-the canto-permit the latter to proceed at'a predetermined speed under adverse trafiic conditions,

traffic on railroad tracks; including: a trafiic track composed of rails and arranged in zones ofinfluence, a trackway source of current connectedacross' saidrails, trackway; means responsive totraflic conditions to reverse the a connection between'atrackway source-and the rails for a portion of a zone and for cutting off connectlonbetweensaid source and rails for the remaining portion of the zone, a car to travel onthe track ,rland car-carried appacation when reverse connections are established and a danger indication when current islcut off between the trackway source and therails. 1 I

63. A train control system-including traffie rails arranged in blocks, twotrackway sources of current for'each block,'each otsaid sources bridged across the traflic rails ofa block, oneof said sources-supplying a train governing, current and theother source supplying a control current tothe trafiic'rails in series, circuit means responsive to thecontrol current flowing in the railsof a block to control the supply of train governing current to the traffic rails of another block, a train,

and automatic means on the trainsubstan-l tially continuously responsive to the influence 7 of the train governing current flowingin the traffic rails of a block being traversed'by a train but not eiiectively responsive to the control currentfiowing in the traiiic rails of i said block.

64a A'system for protectingtrafiic on railroad tracks including a traflic track composed oi rails arranged in blocks, trackway means to supply across the rails at the exit end of a block a clear or a caution train governing current,'a train, a train-carried control relay continuously responsive to the influence of either train-governing current flowing in the rails of the block through which the train is traveling, two train-carried f repeater relays so arranged that when either of said repeater relays is energized the other is not, one repeaterrelay energized only when the control relay is'iniiuenced by clear traingoverning current, the'second repeater relay energized only when the control relay is'infiuenced by caution train-governing current,

and 'train carried-"signaling means controlled to give a clearjor a cautionindicationdepending'upon. which repeater relay is ener-V currentto be connected across the traffic rails across the trafiic railsatthe exitend of the; I

block, in accordance with 'traific conditions aheadyatrain, a train-earned control relay continuously and selectively responsive to the 62., A systemfor automaticallyprotecting influence of the clear or caution train-governing current flowing the rails of; the block, through which the train 7 is traveling, two

train-carried repeater relays so arranged that trolled by the two repeater'relays. I ratus responsiveto variations of influence of the current source and'to give a caution indiously and selectivelyresponsive to 'the in fluence oifclear or "caution train-governing current in the track 'of the block through I which the tra n rs rtra'veling, two train-carriedrepeater relays so arranged "that when' 'either of said repeater relays isenergizedtheother is not and selectively energized when the control relay isinfiuenced by either clear-or caution train-governingcurrent, and clear, cantion and danger train-carried cab signaling circuits selectively controlled by the two re--' peaterrelays.

f 67. A train control systenrincluding traiiic rails arrangedin block's, two trackway sourcesof currentfor each block, each of saidsources bridged across thetrafiic rails of a block, one

a of said sourcessupplying-atrain governing current and theother sourcetsupplying a control current to thetrailic rails inseries, circult 11g, means responsive to-the control current flowing in the rails of abiloclrto control the supply of train governingicurrent to the trailic railsof another bloclga train, and automatic means on the train substantially continuously responsive to the influence of the train gov erning current flowing in the traflic rails of a block being traversed by a train but not 'efiectivelyresponsiveto the control current flowing in thetratlic'railsof said; block. 68. In a system for automatically protect ing traffic on-railroad tracks, the combination with automatic mechanism on, a vehicle Ifor [retarding the movement thereof, of a normally*c1osed'circuitfor governing said mechanism, a permissive speed device having a tendency to assume its lowest speed condition, means controlled by said device for opening said circuit when the actual speed *of the vehicle exceeds the permissive speed prescribed by said device, and normally act- 111g impulse transmitting means comprising trackway elements cooperating with the element on the vehlcle for influencing said device from its lowest speed condition to a variable extent in accordance with the extent of unoccupied track in advance of the vehicle.

69. In a system for automatically protecting trafiic on railroad tracks, the combination with automatic apparatus on a vehicle adapted to restrict the speed thereof to any one of a plurality of speeds, said apparatus having a tendency to impose the lowest speed restriction, of traflic controlled means-acting in opposition to said tendency to govern said apparatus substantially in accordance with the space between said vehicle and another train ahead. r

70. In a system for automatically protecting traffic on railroad tracks, the combination with automatic mechanism for controlling the movementof a vehicle comprising speed responsive means having its controlling condition governed by the actual speed of the vehicle, of a permissive speed means capable of having its controlling condition regulated I by the varying polarity of electrical energy supplied thereto, and means governed jointly .by said speed responsive means and said permissive speed means for retarding the movement of the vehicle whenever the actual speed exceeds the prescribed permissive speed.

71. In a system for automatically protecting trafiic on railroad tracks, the combination with automatic mechanism for controlling the movement ofa vehicle comprising speed responsive means having its controlling condition governed by the actual speed of the vehicle, of a permissive speed means capable of having its controlling condition regulated by the varying polarity of electrical energy supplied thereto, and means governed jointly by said speed responsive means and said permissive speed means for retarding the movement of the vehicle Whenever the actual speed controlling means, electroresponslve means which, when energized, holds the train controlling means inoperative, speed control means for rupturing a circuit through said electroresponsive means when the train is running above a certain speed, a second speed;

control means for rupturing a circuit through said electroresponsive means when the train is running above a certain lesser speed, means for rupturing the connection through said first mentioned speed control means regardless of the speed of the train under certain trafiic conditions, and means for automatically completing a circuit through said electroresponsive means independently of the two speed control means under certain other traffic conditions.

74. A train carried system including: train controlling means, electroresponsive means which, when energized, holds the train controlling means inoperative, a circuit normally completed through said electroresponsive means under safety conditions, means acting under caution conditions for rupturing said circuit and establishing a speed control circuit through the electroresponsive means said circuit to be automatically ruptured when the train exceeds a certain speed, means for rupturing said second circuit under danger conditions, and a circuit including a speed control means through said electroresponsive device to permit the train to proceed at a minimum speed under danger conditions.

Signed at New York city in the county of New York and State of New York this 16th day of October A. D. 1914.

WILLIAM W. MACFARLANE.