US1634557A

US1634557A - Automatic train control

Info

Publication number: US1634557A
Application number: US709779A
Authority: US
Inventors: Thomas M Riggle
Original assignee: RIGGLE AUTOMATIC TRAIN CONTROL
Current assignee: RIGGLE AUTOMATIC TRAIN CONTROL; RIGGLE AUTOMATIC TRAIN CONTROL Co
Priority date: 1924-04-29
Filing date: 1924-04-29
Publication date: 1927-07-05
Anticipated expiration: 1944-07-05

Description

3 Sheets-Sheet 1 'r. M. RIGGLE AUTOMATIC TRAIN coNTRoL- FiledvApr'il 29. 1924v Qkmw.

ivm

July 5, 1927..

July 5, 19,21., 1,534,557

T. M.'R|GGLE AUTOMATIC TRAIN CONTROL Filed April 29. 1924 s sheets-shet 2 .sl +7 f? 54 +9 55 d f'- a a r 9%' l l l INVENTOR. Tf1/@6605 BY 7M, ATTORNEY July 5, 1927.

T. M. RIGGLE AUTOMATIC TRAIN CONTROL I5 Sheets-Sheet 5 Fled- April 29. 1924 l INVENTOR. Z'fZ ATTORNEY Patented July 5, 1927.

UNITED STAT-'Es PATENT oFF-ICE.

THOMAS M, RIGGLE, or OAKLAND, CALIronNIAyAssIGNOn To RIeeLn AUTOMATIC TRAIN CONTROL COMPANY, or OAKLAND; CALIFORNIA, A CORPORATION or CALI- FORNIA,

Application filed April 2.9,

My invention relates to ieeans' for limit.-

ing the speed of a trai-n and tor automatically stopping the train or decreasing the speed thereof when a. block section of rtrack preceding the train is not in normal condition.

An object of the inv'ention is to provide an extremely simple and positively acting electrically andv magnetically operated mechanism which will cause the application of the ytrain brakes when a block section of the track preceding the train is not in normal condition and the train speed exceeds a predetermined value.

Another object of the invention is to pro,- vide means ot' the character described. which will cause the` application of the brakes when the train exceeds a. predetermined speed regardless ot the condition of the track preceding the train.

A further object of the invention is to provide means which will temporarily render the automatic brake applying `mechanism inoperative providing the speed of the train is not in excess oli' .a predetermined value. 1

still further object ot' the invention is to provide a single means associated with the track for causing the operation of the apparatus to effect the foregoing objects.

rThe invention possesses other objects and features of advantage, some oit which, with the foregoing, will beset forth in the tollowing description oi' the preferred form of my invention which isxiliustrated in the drawings accompanying and forming part ot the sptciiication.` It is to be understood that I do not limit .myself to the showing made by the said drawings and description, as I may adopt variations of the preferred orm within the scope of my invention as set forth in the claims.

AUTOMATIG TRAIN CONTROL.

1924. Serial, No. 709,779.

ing train and track elements of the device.

In Figure 1 ot the drawings the portion shown above the track 2 is arranged Ito be carriedV on the train, while the portion included. between the rails -otthetrack .Y is

Y adaptedf to be held .inv substantially xed essociation with respect tothe track.v As here illustrated .the track comprises rails 3 and l and is divided into insulated block sections as in signal control systems, three of such sections 6, 'T and 8 being here represented. In the present embodiment, my invention is used inconnection with the air-brake-system of the train, and accordingly a well known ,type of this system is here diagrammatically illustrated and shown abovevthe representa- 4ion of the track. Included in the brake system is the engineers brakefvalve) connected to the air reservoir 1 2 by reservoir kpipe 13, andconnected .to the brake-pipe 14 bythe branch 15g. As isusual the brakepipe communicates with the distributing valve and triple valves on the cars ofl the train, the v'alvesbeing caused to bring about the applicationof the brakes when the pressure inthe vlorakepipe decreases belowa predetermined point.

The brake-.valve is provided with a suitable control lever 17 cadapted to be placed in various positions, such as release, running andl service, the latter causing a reduction olf the pressure inthe brake-pipe and consequent application of the brakes. ln the present arrangement the mechanism of my invention operates inconjunction with the control lever of the brake-valve, and suitable mechanical actuating means aretheretore associated with -said lever and adapted to ybe operated by my automatic control means. The lever actuatingmeans includes a cylinder 18 which islixedpositioned ad.- jacent thebrake-valve .and in which a. piston 19 is mounted for reciprocation. The latter is provided with a rod 21 which extends through the cylinder. head 22 and is adapted to reieasably 'engage the lever so as tomoye it to serviceposition.

Formedlin the cylinder so as tolie on opposite vsides' of the pis-ton in vall of the posi@ tions thereof are ports 231 and 24 which by means of the pipes r2.6 and 27 aiord the cylinder communication with the reservoir and `brake-pipel respectively. The pipe 26 includes a ,valve k28 which normally CLI maintains suiiicient pressure in the portion of the cylinder Q9 associated with port 23 to exceed the pressure obtaining in the brakepipe. In this manner, under normal conditions, the piston-rod will be held entirely released from the control lever, and the latter may be manipulated at will. However, should the pressure in the chamber 29 be reduced below the brake-pipe pressure, the piston rod will be moved to place the lever in service position and an application ot' the brakes will result.

Accordingly, therefore, means are provided for automatically causing a reduction of the pressure in the chamber 29 when a train` travelling in excess of a predetermined comparatively slow speed approaches a track section which is not in normal condition. As here shown, said means comprises a pipe 3l which communicates at one end with the chamber 29 and at the other end with an electro-magnetically operated application valve 32. The latter includes a valve stem 33 in the form of a magnetic core which is associated with a magnet coil 34 and is arranged to control the flow of air through t-he valve. When the coil is energized the core closes the valve passage 35; however, when no current iows through the coil the core may be displaced by the pressure of air in pipe 31 and t-hereby permit the air to escape through outlet 36 and thus relieve the pressure in chamber29. The coil 34 is arranged in a normally closed circuit 37 containing a suitable source of current such as the battery 37. Associated. with the circuit 3T and arranged in lparallel with each other and the roi 34 is a plurality ot longitudinally, aligned magnetically operated gravity switches 39 contained in shortcircuiting branches 4l. offering low electrical resistance compared with the coil 34. Each of the switches includes an. armature 43 which is normally held raised. 'trom engagement with a cooperating contact member 44 forming part ot' the circuit 37 by means o't the attraction of a relatively weak bar inag net 46 which is strong enough to hold the armature, but not strong enough to raise it from its lower position. it will now be un derstood that if either or both armatures are caused to engage contact member 44, the current will be diverted from the coil 34 through a branch circuit 41 and back to battery 37 with the result that the core 33 will become demagnetized, and the pressure in the chamber 29 may be relieved to bring about an application of the brakes. lt will new be noted that with switches 39 all open, the current from battery 37 will pass through conductor 37a, will be divided between the contact member 44 and a similar member hereinafter more particularly referred to and which is connected in parallel with the member 44, and will then pass through conductor 37b, coil 34, and back to battery through conductor 37C. On the other hand, when one or more of the switches 39 is closed, the major portion ot the current from battery 37 will pass through conductor 37a to contact member 44, through the member 44 to the closed switch or switches 39, through the branches 4l, and thence back to battery through conductor 37C, thus so weakening the current through the coil 34 that the valve 32 will be permitted to open. Means are provided tor causing' the armature 43 to be moved into contact with the member 44 against the resistance of the magnets 46, when the track section preceding the train is not in normal condition. such means being inoperatively disposed with respect to the switches 39 when track conditions are normal. As here shown, said means comprises a relatively strong' magnet 47 associated with each track section and arranged to be moved transversely trom one position to another so that when the train passes thereover the armatures 43 will or will not be aitected thereby in accordance with the condition of the preceding track section. Each ot the track magnets, as here illustrated, is ot the permanent horseshoe type and is mounted on a carriage 43 arranged on an inclined runway 49. The carriage is preterably arranged between and is adaptedto move transversely of the track rails.r The switches 39 are so positioned on the train that when. the train passes b v the track magnet while the carriage is at the higher end ot the inclined runway, the switch magnets 46 and associatedv armatures 43 will pass transversely of the magnet 47 at such distance as not to be appreciably affected tl'iereby, whereas.; with the fmagnet Lcarriage positioned at the lower endet the runway, one y pole ot the switch magnet 43 will pass over in close proximity to a track magnet pole ot like polarity. In the latter event, it will be evident that while the niagnet poles are passi ng. the attraction ot the switch magnets 46 ter the armatures 43 will be neutralized and the armatures will be moved by gravity and the excess attraction of the track magnet to engage the Contact member 44, thereby eitecting the setting of the brakes in the manner preif'iously described.

The proper positioning of the track magnet in accordance with trac-k conditions is here shown effected through the agency ot a motor 5l and an electro-magnetic clutch 52 mounted upon a shaft 53 driven through a worm 54 and wheel 55 by the motor. Carried on said shaft for relative rotative movement thereon is a sleeve 57 which is fixed to a drum 5S about which is adapted to be wound and unwound a cable 59 attached to the tr ck magnet. Connection between the shaft and sleeve is effected by means of the clutch, the winding 61 thereof being ar- LOU izo

ranged on the sleeve While the' magnetic plate or armature .62- carries the Wheel 55. Che motor and clutch are connected in series in ascii-cuit vhaving a suitable source of current such as the battery Gel and provided with a switch 66 whichA is normally retained in closed position by means ot'the track relay 67. A suitable resistance 68 is also arranged in circuit 63 s o `th at Aunder normal Yconditions the current Will be merely suficient to hold the clutch engaged but not enough to rotate the motor shaft. The sleeve and drum vare held in such relation to the motor shaft, thatv With the track clear and the circuit 63 Y closed, the carriage and magnet Will be held vwhich is connected in p'arallelvf'ith the resistance 68. As shown in Figure 4, the circuit breaker comprisesa broke-n conductor ring 70a carried onthe sleeve 57 and insulated therefrom, brushes 70" being utilized to provide the necessary contact therewith. When the magnet is inoperatively disposed, the circuit breaker is likewise positioned; hoivever, When the magnet is in operative position the circuit breaker complet-esa shunt around the resistance.

soon as the track returns-'to normal condition and the circuit 68 again becomes closed, practically the full line current will pass through the motor and the shaft of the lat-ter ivil be roitated. Rotation of the motor shaft Will continue until the track magnet has been moved'to Aits inoperative position,

Vativhich time', as above explained, the circuit breaker Will open the shunt and themagnet Will be thus lleft in saidr latter position.

It will, now be noted thatxthe rails 3 and e oitv each track. section or block form part of a constantly closed track. circuit containing a track relay 67 and a battery l0, and that the relay 67 of each section circuit is arranged to operatev the switch 66 of a section behind it. Thus, as herein particularly shown, the track magnet and mechanism positioned" in vthe track section 7 is particularly arrangedfto be controlled from the track section 8,', it being noted that Whena y tra-iu is positioned in the section 8, circuits Willbe provided through its setso-f Wheels and axles to electrically connect theiailsA and thereby short out theportion ofthe track circuit containing the'relayl Gftof allow the openingjofthe sgivit'ch. In thisqm-anner, the switch (361*iivi'llbe caused te remainopen In this manner until the train leaves the block 8 so that any train attempting toentcr the block 7 While a train isy in block 8Y Will have its brakes -automat-icallyl set in the manner vhereinbefore described..v Itv Will now be noted' that when the4 train lea-ves vblock r8,'th`e normal current flow through the track relay will 'be resumed tojthereby'fc-lose the correspondshown the device-otm-y invention applied to a Vone-Way tracky to'provide -control of a iollowingv "trainY for only one Yblock behind a leading train, itwill be obvious that control. for a two-Way track lor ter more than one track magnet behind a train merely requires the duplicati-on of the Imagnet positioning mechanism and an appropriate system otin Y terconnected trac-k relays similar to those nowv used in block signal systems. will also be noted that the various mechanisms of the device are illustrated throughout'as in the condition of lno-rmal'running oi va train With the track sections in proceed condition, the different controlv positions being described in detail lie-rein in connectionY with the description ofthe various operations of the device'. l

In the even-t that theautomatic control d' mechanism on the train in passing over the track magnet, operates to cause the setting of the brakes, lthe.` latter may only be released' upon the engineer' raising the armatures 43' by hand, whereupon the valve B'is rcseated.` the pressure in'pressure chamber 29 builds upagain andthe piston rod is Withdrawn from operative engagement with :the control lever of thebrake valve toa'llovv'the engin-eer to release thc'brakes.

Means are provided'fortemporarily rendering the automaticsbrake-applying mech* anism inoperativeproviding the speed of the train is not in excess of ay predetermined value. Fed with airfrom the main reservoir 13' through a restricted-port-valve 70, is a volume 'tank 71 which is' vadapted to contain a comparatively limited amount of air under pressure. The volume tank is in turn connected with an electro-magnetically operated pressurevalvel which is providedwitha stem 73 arrangedto 'be actuated by the magnet Corelli".v The valve is: pro vided vvvith a passage 75 which is: normally kept shut byV means of a springpiress dvalrc element 76C Opening ofthe passage 751 is effected by energizing the magnet coil 77 in which the core 74v is arranged, thev coil being contained in an electric circuit 78 which includes' a suitable'source of current such as a battery 1"8.y The passage 75 is connected'ivith a pistonvalve Z9-into which the/air from the passage is arrangedto dis.- cliarg'e when the' valve element 76 is open. Therpsten valve includes@ pistoni 80'- to 'iuO which is liXed a rod 8l having preferably secured thereto a contact 82 which is adapted upon the displacement ot the piston 8O to bridge a pair of lspaced contact ele-ments 88 arranged in an electric circuit 84 having a suitable source ot' current such as the batteries 84 included therein. Contained `in the circuit 78 and positioned to lie at the 'front and rear of the switches 89 are gravity switches 86 ot the same type as are the switches 89, each of which in the present embodiment ot the invention comprises a bar 87 which is normally magnetized but possesses insutlicient magnetic strength to draw a pivotally mounted armature 88 thereto and thereby complete the circuit 78 through the armature and a contact 89. The switches 86 are thus also arranged to pass over a pole of the track magnet when the carriage ot the latter is in operative position, or in other words, when the track section ahead ot the train is not clear. The poles ot the bar magnet 87 and track magnet 47 which are arranged to cooperate are ot unlike polarity, so that as the weaker magnet 87 passes over the relatively strong pole of the track magnet, an increased magnetic strength will be induced in the magnet 87 and the armature will be drawn upwa-rd thereby to close the circuit 7 8. It will be noted that the pivoted switch armature 88 is arranged to normally lie in a support 90 and is held close enough to the contact 89 thereby as to insure its raising as the track magnet passes thereunder. The closing ot circuit 78 being thus elfected by the drawing ot the armature 88 against the contact 89 will now cause the opening ot the valve 72, so that the contact- 82 will be moved against the contact elements 88 to close the circuit 84 in the previously described manner. The circuit 84, it will now be noted, also has electro-magnet coils 85 included therein, each ot said coils being preferably arranged t-o encircle the bar magnet 46 of a switch 39 and being capable,` when excited, ot increasing the pull of the magnets 4G to prevent the engagement or armatures 48 with .members 44 against the pull. of the track magnet. The circuit 84 also provides a branch circuit around the coils 85, and which circuit is arranged to simultaneously energize coils similar tothe coils 85 for a purpose to be hereinafter more fully described. Assuming, then, that the track is not clear and that the train has passed over the track magnet to close the switch '86, current will flow through coil 77- and air will be forced into the piston valve 79 to ett'ect the closing ot circuit 84, thus preventing the automatic application ot the brakes. lt will be noted by referring to Figure l that the valve 79 is provided with a relief port 91 which is adapted to be uncovered by the piston on its forward stroke; by varying the position and size of said port the duration and time ot closing and opening of the circuit 84 'may be readily predetermined. Furthermore, relative positioning of the

switches

86 and 39 must be such that when the train is traveling at a speed not greater than the permissive speed, the coils 85 will have been energized by the time the switches 89 pass over the track magnet to thus prevent the application of the brakes in the manner indicated; whereas, it the train is moving at a greater than permissive speed, the brakes will be automatically set. In this manner. a train may be allowed to proceed into an adverse block, but only when going slowly enough topermit its stopping within a short distance, the mechanism thus` providing what may be conveniently termed a cautionspeed control.

lVith the circuit 78 closed at the switch 86, the current Jfrom battery 78 will flow through conductor 78il to and through the switch 86, thence through conductor 78b to and through the operating coil 77 ot the valve 72, and thence back to battery 78 through conductor 78". When circuit 84 is closed between contacts 83, its current will tlow from the battery 84 through conductor 84n to a contact 83, thence through the bridge contact 82 to the other contact 88, thence through a conductor 84h to the coils 85 which are here shown connected in series, and thence back to battery 84 through conductor 84` p soon as a magnet 86 has passed over the track magnet, the armature thereof will drop to thereby break the circuit 78 at Contact 86, and thus allow the closing of valve 72, whereupon the piston 8O will tall by gravity las the imprisoned air escapes from thereunder and the bridge contact 82 will be drawn away trom the contacts 88to break the circuit 84,

Means are also provided in connection with the mechanism just described :tor insurw ing an application of the brakes in case said mechanism fails to properly function or release, as for example, it the circuit 84 should not become broken within a reasonableV pe-` riod after the switches 89 pass over the track magnet. As here illustrated, said means comprises a differential-piston-valve 92 providing a cylinder 93 having bore portions of different diameters at opposite ends thereof. The bore portion of smaller diameter is connected to the pipe 3l, while that with the larger' diameter is connected to the volume tank 7l. Mounted in the smaller and larger cylinder bore portions respectively are pistons 494 and 95, such pistons being fixed together in spaced relation whereby they may be simultaneously disposed in corresponding parts of their bores. Normally, Y

the

It will now be noted that asV as indicated in Figure 1, the pistons lie at opposite sides ota relief p0rt97 formed inl the cylinder with the piston 9,5. ,disposed/at the inner end; of its stroke and the ,piston 91 disposed ,at the outer end of its stroke; how' ever, should either vof the armatures lS8 fail to become disengaged from the magnets 87 and thereby leave the circuit 84 indefinitely closed,.the pistons 9a and 9.5, by reason of` munciation with the 'cylinder at the outer side ofV the piston 91 and the pressure in the chamber 29 vwill be relieved through port 97 to e'ect the automatic application of ther brakes..

Means are also included for `causing the automatic application ol'f the brakes when the track section preceding the train is clear butthe train exceeds a predetermined maximum speed. As here shown, said means are adapted to be actuated by means associated with the track, and, in fact, are arranged to be lactuated by the same track magnet 47 which operates the train brakes when the track is lnot clear. Connected in the .circuit 84; in parallel lwith theswi-tches 39 therein and operable similarly thereto ris a plurality of switches 101., v.while switches102, .adapted to operate similarly to the switches 86, are

arranged in parallel with .the latter in thev circuit 7 S. Switches 101 and 102, it will be noted, are arranged in alignment longituf dinally of .the train with .the former between the latter land :are so positioned transversely of the switches 39 and vS6 that they may be affected bythe track magnet only when the latter is positioned in the upper or clear position. The

switches

101 and 102, it vwill b e noted', respectively include

bar magnets

103 and 104 land pivoted

armatures

106 and 107, the armatures 106 being, arranged to contact, when displaced downwardly, with a common contact member108j connected in the circuit .of `battery .37 in parallel with the contact 441-, while the arma.-

' tures 107 are` arranged to contact v,with

switch contacts 102 when moved upwardly,

the. armatures thus being similarly operable to those of the switches 139 and :86 respecf tively. Coils 10.9 are mounted on magnets 103, such vcoils being similar to and connected in parallel. with the coi-ls 85.

By reference-to. Figure `5, it will be noted that with the track magnet 17 in iltslower, or adverse, position, as sho-wn in Adotted lines, one pole'111 thereofis arranged rto lie ink a common vertical plane with the switches 39 andl 80, while the other pole 112 of. the magnet will lie in a .common verticalplane with the vswitches 101'and 102. `It will now vbe further noted :that with. the magnet pole-111 having .a given polarity, .the lower poles of the .magnets 16 of the switches BQvmuSt have a' like polarity thereto, while the lower poles of' the magnets 8 7' of the switches 86 must have an opposite .polarity therefrom, in order to insure the desired operation of the device. Onjthe other hand, the'switches 101 and l102 mustr ber inoperative under adverse track conditions, which result is simply accomplishedby havingl the polarities of the lower poles of their magnets the same as those .of'magnets 46 and 87 respectively, so

that the' polarity ofthe pole 112, which is v obviousl-y the opposite of that of pole 111, may positively Vprevent the operation of the switches `as the pole 112 passes thereunder, by respectively vneutralizing and strengthening the polarities of the

magnets

104 and 103.

VVllhen. the track magnet 17 is in its normally raised, or favorable position, as show n in full lines in Figure 5, the pole 112 thereof will be laterally displaced from both sets of switches, and therefore cannot sufciently influence them .to cause .their actuation.

The pole 111, however, will now bel inpfosiy tion to effect the operation of the

switches

101 and 102, and since the polarity relations will be the same as when the pole 111 Was in position to cooperate lwith the Vswitches 39and- 8.6 for y their actuation, corresponding operative ,effects .will be obtained. It will now be noted that in. the latter instance, the spacing .of adjacent switches l101 and 102 will ,be'made such. as toallow thek operation of Ithe trainhat ,any speed up to the allow'- able maximum,;thus providing what might be .termeda full-,speed .control in contradistinction tothe caution-speed control afforded throughy the switches39and 86. A

By providing more than oneof' each of the switches i39and101 4operation of the de.- vice is assured, Yit-loeing evident that the proper operation of' any ,one of l these switches will short outthelcircuit 3 7 and thereby cause the setting lof -,the brakes. Switches'S-or 102 should be positioned both ahead .of rand bolliillffl the, SN-Trimbos .'39 plld 101 respectively toyallow reverse .operation oit the'train .on-a -tra ckarrajin-'ged `tor @two-V waycontgrol, since one of.the.;torn-ierv must operate aheadof the latter fwi-thwghich it is associated in order to prevent setting of the brakes.v 4 Y Y ,ltr-will nowlievevident that a mechanism has been provided: which. will not .only cause l train, a permanently magnetized track magried on the train adapted to be actuated byV said track magnet to eii'ect an application of the air brakes when a section preceding the train is not in normal condition, and electromagnetically operated means carried by said train and adapted to be actuated by said magnet to prevent. the application of said brakes by said lirst means when the train in approaching said section is travelling below a predetermined rate of speed.

2. In an automatic train control, the combination with a series ot insulated track sections and an air-brake-system carried on the train, a permanently magnetized displaceably mounted track magnet associated with each of said sections, means on said train adapted to be actuated by said track magnet for effecting an application or' said brakes when a track section preceding the train is not in normal condition, and means adapted to be actuated by said track magnet to prevent the application of said brakes by said iirst means when the train is approachingr said section below a certain rate of speed.

3. ln an automatic control for trains, the combination with a series of insulated track sections and an air brake system carried by the train, of Va displaceable track magnet associated with each track section, means operative to displace a track magnet when the associated track section is not in normal condition, means carried on the train operative to effect the application of the air brakes by and only when the train passes a displaced track magnet, and means carried on the train operative by said displaced magnet to prevent the application of said brakes by said preceding means providing the speed of the train is below a. certain rate.

el. In an automatic train control, the combination with a brake-system and a series of insulated track sections, a magnet associated Awith each section, electromagnetically operated brake controlling means comprising an electric circuit, a magnetic switch in said circuit adapted to be actuated by a magnet, and a second switch, and an electric circuit in which said second switch is contained adapted to magnetically influence said first switch and thereby prevent the ac tuation thereorp by a track magnet.

' 5. An apparatus in accordance with claim 4l characterized by the second switch being positioned for actuation by a track magnet.

6. In an automatic train control, the com bination with a series of insulated track sections and an air-brake-system carried on the train, a track magnet associated with each of said sections, means on said train adapted to be actuated by a track magnet for elect ing an application of said brakes when a track section preceding the train is in ad verse condition, means adapted to be actuvk plication ot the brakes under said latter condition in case said last means fails to allow the application of the brakes by said iirst means after preventing said application for a certain interval.

7. In an automatic train control, the combination with a brake-system and a series of insulated track sections, a track magnet movable to assume different positions when the track is in normal and adverse'conditions, means operative by said track magnet to cause the actuation of the brakes when the track is in adverse condition, means operative by said track magnet to cause the actuation of the brakes when a predetermined speed is exceeded by the train regardless of the condition of the track, and means operative by said track magnet regardless of thecondition of the track to render inoperative said brake actuation means when the train is travelling below a predetermined speed.

8. ln an automatic train brake control, the combination with an air brake valve and a series of insulated track sections, a track magnet movable transversely of a track section to assume ditlerent positions when the track is in normal and adverse conditions,

means operative by said track magnet tocause the actuation of the air brake valve to set the brakes when said track is not in normal condition, means operative by said track magnet to cause the actuation of the air brake valve to set the brakes when a predeterminedspeed is exceeded, regardless ol the condition of the track, and means operative by said track magnet to render inoperative said air brake actuation means when the train is travelling below a prede termined speed.

9. ln an automatic train brake control, the combination with an air brake and a series of insulated track sections, a track magnet movable transversely of a track section to assume different positions when the track is in normal and adverse conditions, and means operative by said magnet to cause the application of the brakes when a predetermined speed is exceeded by the train when said magnet is in either of said ,'pfositions.

10. In an automatic train control, the combination with an air brake and a series of insulated track sections, a track magnet movable to assume different positions when the track is in normal and adverse conditions, and means operative by said magnet to cause the application of the brakes when lll) maximum speed, or it tlie track is in adverse condition, the train is travelling under a predetermined minimum speed.

12. In anautomatic train control, the combination' with a brake system and a series of insulated track sections, magnets arranged in said sections, electro-magnetically operated means carried on the train adapted to be actuated by said magnets to effect an application of the train brakes Y' when the track is not clear, electro-magnet# ically operating means Carried by the train adapted to prevent the actuation of the brakes by said means providing the train is travelling below a predetermined minimum speed, elect-romegnetically operating means carried by the train and adapted to be actuated by said magnets for causing an application ot the brakes regardless of track con* ditions, and electro-magnetically operating means carried by the train adapted to be actuated by saidl magnets to prevent the application of the brakes by said last means providing the speed of the train is below a predetermined Vmaximum value.

13. In an automatic train control, the combination with a l brake system and a series ot insulated track sections, a track magnet associated with eacli section adapted to lie in different positions when the associated section is in normal and adverse coiiditions, electro-magnetically operated means carried on the train adapted to be actuated by one of said track magnets to effect an application of the brakes when the magnetis'in the position occasioned by adverse track conditions, electro-magnetically operated means carried on the train arranged to be actuated by said magnet to prevent the application of the brakes by said first means providing the speed of the train is below a predetermined minimum value,

electro-magnetically operated means carried on the train adapted to be actuated by said magnet tc effect an application of the brakes when the magnet is in the position occasioned by normal track conditions, and electro-magnetically operated means carried on the traink adapted to be actuated by said last mentioned means providing the speed l of the train is below a predetermined maximum value. i

14. In an automatic train control, the

combination with a brake-system, track magnets, electro-magnetically operated brake controlling means comprising an electric circuit, normally inoperative means adapted to be actuated by a track magnet to shortcircuit said circuit, a switch, and an electric circuit in which said switch is `contained adaptedto iniiuence said means to prevent the-actuation tliereotby track magnet.

15. In an vautomatic train control, tlie combination with a brake-systemrcarried o n the train, track magnets, means on said ltrain adapted to be actuated by a track magnet tor effecting an application of said brakes, means adapted to be actuated by a i track magnet to prevent the application ot said brakes by said first means when the train is approaching said section below a predetermined maximum rate oi' speed, and means opera-tive to cause an application of the brakes under said latter condition in case said last means fails to allow the application ot the brakes byv said rst means after preventing said application 'for a certain interval. In testimony whereof, I have hereunto set my hand at Oakland, California, this 16th day of April, 1924.

. THOMAS M. RIGGLE.