US1920197A - Train control system - Google Patents

Description

Aug. 1, 1933. A. E, HUDD 1,920,197

TRAIN 'CONTROL SYSTEM Filed Oct. 6, 1926 4 Sheets-Sheet l Pal/W15 CLfAF C140 7/0/Y Elfed E. Huid www@ 4 Sheets-Sheet 2 Elfred E. Huid A. E. HUDD TRAIN CONTROL SYSTEM Filed Oct. 6, 1926 Aug. l, 1933.

Aug. 1, 1933. A. E. HUDD TRAIN CONTROL SYSTEM Filed Oct. 6, 1926 4 Sheets-Sheet 3 -I-Lw-s'l-TIU-I- Elfred E. Hu .fili 72M Aug. yl, 1933. A. E. HUDD TRAIN CONTROL SYSTEM Filed Oct. 6, 1926 4 SheeiS-Sheet 4 l A. E I/ Pw, NS v// IliL NS kQ/V mm w 'TMS Patented Aug. 1, 1933 turen STATES orricx:

TRAIN CGNTROL SYSTEM Alfred Ernest Hudd, Evanston, lli., assigner, by mesne assignments, to Associated Electric Laboratories, Inc., Chicago, Ill., a Corporation of Delaware The pesent invention relates in general to train control systems and more particularly to systems of the intermittent inductive type.

It is well known that the braking curve of a vehicle or train varies, with the grade conditions, being proportionately longer for down grades and proportionately shorter for up grades.

Speed control systems of the general type to which the present invention relates employ a controlling element by which the speed of the vehicle can be regulated as desired, and this controlling element, which is preferably a cam, has an outline and a normal speed of movement calculated with reference to normal, that is to say,

a level grade condition, whereby the speed reduction curve will conform to the normal braking curve. However, in .order that this same conformity may be maintained on condition oidown or up grade, it is necessary that the rate of movement of the controlling element be appropriately varied, the movement of said clement being retarded for down grade conditions because of the greater length of the braking curve and being accelerated for up grade conditions because of 4'he shorter length of the braking curve. By such regulation oi the rate of movement of the controlling element it is possible to take the fulles.; advantage of track capacity while at the same time to fully conform to conditions of sale running.

One of the main features oi the present invention has to do with` the provision of means for causing the rate of movement of the speed controlling eleinent to be determined just before the vehicle enters each caution block, and in the provision of means for causing the rate oi Inovement, while passing through the block, to be such as to only require the vehicle to keep within the true braking curve oi that block.

A second feature of the system has to do with the provision of means whereby the system discriminates between absolute stop signals and stop signals which may be passed at low speed after an acknowledgement has been niade by engineman.

A third feature has to do with the provision of a system in which cab signals for conveying all necessary indications to the engineman are l provided, which renders the system perfectly 5U adaptable for operation without wayside signals between interlocking, crossing loops, etc.

Other features include the provision of an improved type of trackway element for transmit- 7 4 ting controlling im ulses from the trackway to M the vehicle, an improved. inductor responsive to such impulses, and the utilization of a flexible element for picking up the impulses transmitted. Y lOther features have to do with the provision oi a system in which the design and construction of the mechanism used to accomplish these results is simple, inexpensive, and sound in fundamental principles, both mechanically and electrically. l

The invention is illustrated in the accompanying drawings, in which- Figs. l, 2 and 3 taken together diagrammatically illustrate the speed controlling mechanism applied to a vehicle.

Fig. 4 illustrates details of construction of certain parts of the apparatus not very clearly shown in Fig. 2.

Fig. 5 illustrates the speed control indicator which is carried in the cab of the vehicle.

Fig. 6 is a chart illustrating several sections oi trackway, the speed reduction curves which must be closely followed when passing through such sections when caution signals are passed, and trackway elements with vcontrolling circuits superimposed on an assumed existing signalling system.'

Fig. 7 shows a section of trackin elevation with a trackway element xed thereto. The trackway element is a sectional View taken on line A-B oi Fig. 8. On the trackway sufcient of the locomotive is illustrated to enable the showing of an end View of the locomotive inductor connected to a journal box of the locomotive.

Fig. 8 is a side view in elevation, of Fig. 7, except that in Fig. 8, no part of the locomotive wheel is shown and the track magnet is shown complete, a section of the covers of the inductor and magnet only, being broken away.

Fig. 9 is a top view of the locomotive inductor shown in Figs. 7 and 8.

Fig. l0 is a side View of the magnet 121 shown in Figs. 3 and 8.

Before describing the operation of the system as a whole it is considered advisable to describe the construction and function of the apparatus shown in the various gures. The electro-pneumatic valve EPV shown in Fig. 1 is of the general type used on locomotives in train control systems, While the associated. actuator consists of a cylinder 11, piston 12 and special brake handle 13 connected to an existing standard type brake valve.

The speed controlling mechanism shown in Fig. 2 is in practice suitably mounted and enclosed in housings located on the locomotive. Included in this equipment is a speedometer havranged to be released and lowered at varying rates dependent on the character of the trackway sections encountered.

The rate of movement of arm 65 with respect to the rate of movement of the train is varied by mechanism under control of a grade selecting magnet 4:1. This magnet becomes deenergized when leaving a section to permit a geared sector 4S, carried by it, to engage a pinion 78 continuously driven by pinion '78', gears 60', worm wheel 60, worm 62, shaft 58,worm wheel 57 and worm 56 on the speedometer shaft. After a certain distance of movement of the train a pin "77 engages a Vlink '70 or 70', depending on the direction of movement, and if the grade selecting magnet 41 has not been re-energized this pin moves the link engaged, towards the periphery of a pair of clutch surfaces 61 (see Fig. 4) At the proper time, brake magnet is Vdeenc-irgized andv clutch magnet 59 is energized as will be later described, to pivotally secure the link and armature 46 of magnet 40 between the clutch surfaces before they have had time to fall. The armature LioL 46 and the associated permissive speed indicating arm are then carried downward at a rate jointly dependentv on the speed of the train and the distance from center at which the link was connected to the disks 61.

The permissive speed indicating arm is pivoted to a slidable member 63 and is of such a shape that by the sliding of this member, by means of screw 6/1, the permissive speed indicating arm may be lowered or raised to normally indicate any desired maximum permissive speed. The changing of the pivot with respect to trig- 'ger 69 is also effective to change the rate at which the trigger will operate arm 65. The lower the arm the less it will be moved by trigger 69 and the-rate of movement will be decreased. This is truebecauce the lowering of the arm 65 increases the` distance between its pivot and the point of contact of the trigger.

65T and for this purpose reference is made to Figs.

`oi Ya'bracket 103 which is made of iron and is provided, at its other end, with a pole piece for,

attracting the armature away from the pole piece extending from bracket 102. This collector brush 97 and part 103 are also secured to the journal box by a webbed member 101 made of brass or other non-magnetic material. Since the brush 97 is flexible it may be located so that it comes into very close proximity with the trackway elements it passes over them, and therefore fori. an e'icient path for the now of magnetic hun between them. A nonmagnetic plate 120 is secured to the brackets 103 and 102 and acts as a support for a horse shoe magnet 121 (see Figs. 3 and 8) and for the contact screws i222 and 123, both oi which are insulated from the support The armature 105 pivotally secured by a bracket to the upper or south pole of the horse shoe magnet, in an efficient magnetic circuit therewith, so that the armature itseli becomes of the same polarity. The extensions of 102 and 103 to which pole pieces are secured are located in close proximity to the north pole of the horse shoe magnet, so that the pole pieces on the brackets 102 and 103 are normally of the same polarity as the lower pole piece oi the horse shoe magnet. This causes the armature 105 to be held biased to either pole piece to which it is moved. Secured to the pole piece on bracket 103 is a winding 121i which is effective when energized to strengthen the existing polarity in its pole piece and to weaken or reverse the polarity in the pcie piece associated with bracket 102 so that the armature will be attracted to the pole piece or bracket 103, if it is not already in position.

A suitable non-magnetic cover 105is provided which cooperates with. a base plate 107 and protects the mechanism against weather.

The trachway magnet ior influencing the inductor armature, independent oi" the associated winding 12a, will now be described. Two cobalt steel permanent magnets li and 112 are secured within a non-magnetic housing by special bolts 106 and 111 and associated clips 113 and 113. The upper ends of these bolts are brought out through. appropriate openings in the housing 110 and are with the outside thereof. The bolt 111, in addition to securing one end oi the magnet to the housing, is also utilized to secure the entire unit to a rail ci the traclrway through. the medium of an iron clamp 114 and yssociated hook bolts 115. The clamp 114i so constructed that it secures the housing of the track magnet to the rail, but a distance therefrom of approximately 3 inches and is of such proportion as to form an efficient magnetic circuit between the rail and that of the permanent magnet. The upper surface or" bolt 106', which forms the opposite pole piece for the permanent magnet lies in a plane parallei to the top ci the trackway, and the end of the housing 110 extending to the right, as illustrated in Fig. 8, is secured to the rail by a bracket similar to 114i except that, there is no magnetic connection at this point, non-magnetic material. being used. The construction of those trackway elements using electromagnets is the saine except for the substitution of an electromagnet for the permanent magnets shown,

1f we assume that the pole piece 125 represents the north pole of the permanent magnet and that the brush collector 97 of the inductor passes thereover, a magnetic circuit for causing armature 105 to move to the right will be completed as follows: from pole piece 125, collector brush 9'?, ironbraclret 103 and its associated pole piece, and from the south pole of the permanent magnet represented by the tract;- Way rail, the Wheel of the locomotive, its axle and the associated journal bof; 106, iron bracket 102, and its associated polo piece. Since the pole piece associated With bracket 192 yis now associated with the corresponding poles of each of the permanent magnets the magnetic attraction lor the armature 105 will be materially increased, ivhile the other pole of the trackway magnet will be associated With the pole piece attached to bracket 103, neutralizing the normal polarity produced in it by the lower pole of inagnet 12l. rThe armature 165 will therefore be shifted to the right when the inductor brush has passed beyond the permanent magnet tracli'way element and the polarity of the pole piece associated With the bracket 163 Will again be deterinined by the polarity of the lower pole of magnet 121, but Without effect, as the armature 165 is now biased to the right by the pole piece associated With bracket 103, which has the saine attractive force as the pole piece on the bracket 102.

Before going into the operation o the equipnient on the locomotive under the influence of the various tracliyay elements, an explanation will he made oi the locomotive circuits.

The various circuits of Figs. 1, 2 and 3 are shown under normal 'running condiin which conditions the detector relay 82, o-pneuniatic valve inaenet 22, high-speed 3, caution relay 33, l te control nia/gne .ncl grade selecting magnet i1, are all normolly energized by current from a single twelve voit cattery which is carried on 'the locomotive. ln order to .make the circui disclosure as simple as pos battery has been diagramma-tin SiblS b cally repeatedly shown, with its positive pole grounded.

The relay is energized from battery applied gh the contact springs Si) of the clutch to prevent the geared sector carried by its armature 93 from being driven by Worm 91.

The electropneurnatic valve magnet 22 is enerover a circuit extending from battery through contact springs 96, conductor "J6, contacts conductor 25, winding or" magnet 22,`

upper contacts of the acknowl" f sw n Eil, armature and contact or" Lon relay and the working contact and latin 27 to ground. An alternate path over which this magnet may be held energized, when the train is at a stop and contacts 27 are opened, entends through contacts 35, conductor 24 to ground through contacts 81.

high ceed relay is shown energized over a lock 1g circuit extending from battery through c., of the gade selecting niagnet, the lower winding of relay 2o and the con tact and grounded armature of this relay. This relay was or lly energized by the move n,4v it of the armature illof the pickup relay to the rig which occurred when the relay p.- over permanent magnet. rlhis circuit entend-Y ed from battery supplied through contact 42, the upper winding relay 25, conductor 74: the rffht contact and grounded armature 195 of the pickup relay.

The cantieri relay 33 at this timer is held ne ized over a locki ending 'from batte through contact d3, the Winding of relay 33 through its fr .nt contact and grounded armabeen supplied o it through the lower contacts of Witch K, conductor 68 and contacts #il at a time vhen the right portion of armature 46 of magnet e0 was in its highest position.

The grade selecti magnet l1 is energized only through a circuit including conductor 'I5 and the .Grounded inductor armature 105 in its initial. po on and, thercore, releases its armature Li7 and the sector 48 carried by it every time the locomotive passes ver permanent magnet and is reoperated by over an energized elocti'o-niagnet, the respective polarieing arranged accordingly. The reset coil is normally deenergized and only cornes into nient track magnet and two electro nets are alongside the track at the exit oi: each block, and a third electroniagnet placed just within the entry ol' each block, as

shown in 6.

Referring now to 6, explanation of the ay circuits Will he made.

ln the @lith the armatures ll and 152I o this latter relay in this position the current flow to the polarized relay 153 in the next block. to the lot is .such that its armatures are inoved to the leit- Wliich is opposite to tne position of the armatures 151 and 152.

Under these cond ons it will he noted that the side indu tors of the blocks having heir semaphores in clear position will have their number l electr? gaetlc tra ,yay elements included in the cuit with the trackyvay battery when the elated relay 155 becoines energized. This, it will he understood, occurs when a vehicle enters the clock when a circuit may traced from the lower half of the tracliway battery through the Winding of relay 155, L axle and Wheels, the lower rail, the loner arma ture of the po.' ized relay and its left contact to the other terminal of the lower half of the tra-ckvvay battery. Upon completion of this circuit the rel..y 11.55 actuates and completes the second path over t -e above traced circuit which includes the up, er and loi-.yer armatures of the polarized relay 153 and #l elec romagnetic trackivay elei The block; which has its semaphore icati g caution has a circuit prepared for the e"ectroniagnetic traclvvay lement of that bloc-lc. the lower half of the traclrway battery through the right contact and armature 1:52, armature ll and its right contact, the winding of the electromagnetic trackway element, the armature front Contact of the approach relay, and back to the lower half of the traclivlay battery. Since the polarized relay across the rails of the block occupied by the vehicle is shunte-:l out its armatures are in the neutral position. In this position the circuit for the third electromagnetic trackway element is prepared and This circuit extends from CII .rotate the sector e5.

ii the associated approach relay is operated the circuit of the third electromagnetic element is completed, from the upper half of the associated trackway battery, middle contacts and armatures of relay 159, in neutral position, winding ci the #3 electromagnetic clement, and through the armature and contact oi the associated preach relay baci: to battery. Where an absolute stop must be niade this latter electromagnetic tracliway element is omitted.

If a train enters a block in which the se1naphore or roadside signal indicates a clear condition, as illustrated by the bioclr. signal shown in Fig. the following operations will take place; the inductoi.' on the locomotive upon passing the permanent magnet track yelement will deflect its armature from its initial to its alternate position thereby breaking energia ing circuit or the selecting magnet fil. |The armature oi the magnet al does not fall a suhicient distance to break; either pair of its contacts, because, bei re this can occur, the portion 5l of the sector 5 carried by the armature, engages pinion 78. Ten feet of travel of the train will canse the et to be rotated suiiiciently to cause 'to rc ate off teeth 51 and drop into engagement i p" ion l5 through its teeth 50 and thereby permit-the armature i7 to open its contacts Before the locomotive has passed ten iect i iyond the permanent magnet the electro f u' dt traclway element will be encountered. Since this electroniagnet is energised when encountered under clear conditions, as shown bythe circuits oi riig. 6, the inductor armature 1435 is deflected back to its initial position. re-ener- This causes t' gization of magnet l1 and the consequent restoration of sector e8 before contacts 'i2 or '13 have opened, preventing anything further occurring at this time.

1f now the locomotive is about to enter a caution block, as indicated by the second wayside signal shown in Fig. 6, a permanent magnet will be again efective to bring about the deencrgization of the grade selecting magnet 41. Since a caution block has. been entered however, the electro-magnet wayside element #1 lwhich is located within ten feet of the permanent magnet will be deenergized at this time and the #t2 electro-magnet energized instead as illustrated in Fig. 6,' therefore, pinion 78 continues to fis soon as the locomotive has traveled ten feet, the sector 43 rolls off from portion 5l onto its portion 5) thereby perinitting the armature or magnet el to drop suiiiciently to open. the locking circuit of the high-speed relay 25 at its contr` cts 42. This relay upon be coming deenergized, at its contacts 28 opens an other point in its locking circuit, at its contacts 25 removes ground trom one of the branch. conductors extending to the magnet 40, at its contacts 27 disconnects ground from a branch circuit extending to the winding of the electro pneumatic valve magnet 22, at its armature 30 opens the circuit of lamp G and closes that of Y; and at contacts 29 closes a pointin the operating circuit of the clutch magnet 52. At the saine time that sector 48 rolled ofi its portion 51 the pin '17, carried by it, engaged the arm 70. As the locomotive proceeds arm 70 will be moved toward the periphery of the disks 61 (see Fig. 4). When the arm 70 is at some intermediate point however, the #2 electro-magnet will be encountered by the locomotive and as a result inductor armature 105 will be deflected from its alternate to its initial position.

Since however, relay 25 is deenergized at this time, the switching of the inductor armature from its alternate to initial position opens the only remaining circuit or" the brake control magnet 40, the circuit of this magnet having extended from battery through the winding of 40, contacts 36 ci the relay 33, and the inductor armature in its alternate position and ground. The armature of the magnet 4.0 is prevented from falling however, by the energization of the clutch magnet 59 which occurred when its circuit was completed from ground through the armature 105 of the inductor in its initial position, conductor 75, contacts 29 of relay 25 and contacts 37 of the relay 33. Ey reierring to ll, it will be noted that the arm '70 is ordinarily suspended between two hat surfaces 61 which are under the control of the clutch magnet 59. When the magnet 59 is energized the arm 70 is secured at a point interme diate to the recessed portion of the Hat surfaces G1 and their periphery, the exact location being dependent upon the gradient and length of the particular bloclf; in which the locomotive is traveling. This distance is determined by the distance between the permanent track magnet and the #2 electro-magnet.

As the locomotive proceeds the arm 'l0 and its connected armature i6 are gradually carried downward with the result that the pivoted member 59 and the permissive speed indicating arm i 65 are lowered by cam 178 at a rate of speed dependent rst upon the speed of the train and second, upon the speed reduction curve selected, as determined by the distance from the center of the disks 51 that arm '7U is being held.

Since the link may be secured between the surfaces 61 at any point, determined by the spacing of the #2 electromagnet with respect to the lpermanent magnet, the rate of falling of arm 65 for a given vehicle speed is infinitely variable and can be automatically adjusted at the entrance ci each block in order to force the engineman to keep his vehicle at or below a speed which is commensurate with the braking distance to the stop signal.

In the foregoing, only the controlling functions of the inductor and its relation to clear indications and in the initiation of the grade selection when caution indications are encountered have been taken into consideration. The actual control of the brakes of the train will now be tairen up.

Asprev'iously stated the existing standard type of automatic brake valve is equipped with an applicator which consists of a cylinder 11, piston 12 and special brake handle 13. An appropriate air ill connects the cylinder to the electropneumatic valve controlled by solenoid 22. The cylinder ll is normally open to atmosphere through valve 15 and opening 16, and air pressure from the main reservoir is normally acting against the diaphragm ll to keep the valve 18 closed and valve l5 open. An outlet 20 is provided in the high pressure chamber 19, but this is normally cle-sed by a magnet 22.

rihe operation is as follows:

When the @PV magnet 22 is deenergized, the diaphragm 17 collapses after a certain predetermined tiine has the duration of which is determined by the area of valve port 20 and the inlet orifice 2l. For instance, if the high pressure .chamber 19 is connected to a reservoir and the orice 21 is smaller than the port 20, then determined sett the time element referred to can be considerably to an intermediate position contingent on the increased. In practice, however, the structure of chamber 19 and the relative areas of the ports and 21 are adjusted to allow valve 1S (connected to diaphragm 17) to open in about 6 seconds aiter the release oi the EPV magnet. A Whistle W is provided for the purpose of causing an audible Warning to be gir-en immediately when Valve 2Q opens, the pressure in chamber 19 exi I tlnnug" the passage -stances permit, the engineer can take action to close the valve 20 as wili be described later.

t will he noted that the valves .1 8 and l5 are fixed to the saine shaft so that the opening o 18 closes l5 and vice When. 18 is closed the brake handle 13 may freely pushed hack to normal running position as the cylinder 11 is then connected to atmosphere through valve 15 and orifice 15. One terminal of the magnet 22 is normally connected to the negative pole of a battery through speedometer contacts 52 and detector contacts 96. The other terminal of the magnet is normally connected to ground Via 'three branches. One branch extends through contacts and 2'? ot relays 33 and 25, respectively; and another branch extends through contacts 35, conductor 24 and normally closed con ce.; 7l of the electro-pneumatic valve EPT-J; while when the Vehicle is stationary, a third path extends from ground via the zero contacts 81, conductor and contacts oi caution relay It will he noted that all of those connections to the grounded o.; the battery pass through the cont 35 of the caution relay 33 and through normally closed contacts ci the acknowledging key Freni the foregoing, it will be seen that so long as the speedoine er contacts 52 and the detector contacts 95 are closed, the EPV magnet 22 will remain energized far as this side of its circuit is concerned.

If now the contacts 52 are set at such a height that they Wiil not he opened unless the disk 53 on the speedometer rises above a preg, say "To miles per hour, the speedometer contacts will not he ope ed, unless this speed is exceeded.

if the train exceeds lo mph., disk 53 will rise and open contacts causing the decnergiaation of magnet 22. Upon a consequent release of the Valve 29 air is exhausted through whistle W to :vai-n the engineer that if at this stage the speed is not red to 7G mph. Within sii; seconds after contacts 52 are opened a brake application will glace, because at the termination of this sn; second period diaphragm 17 will collapse Causing valve i8 to open and admit full reservoir pressure to the actuating brake cylinder ll thereby moving the brake handle 13 to kservice position.

Since the circuit of magnet 22 has not other-- wise been distui as soon as the speed has been reduced f to again close, the magnet 22 will again hocoine energized. As soon as the pressure in chamber hecomes surlic Ait valves 15 and 18 are restored and the en n may then restore the brake handle 'to I ning position.

On passing a distant or caution signal, (which indicates that the next signal is at st-oy) the inductor armature is deflected from its initial to its alternate position, as previously explained, to open the circuit of the grade selecting magnet il permitting the sector 48 to fall upon the pinion 28, which rolls the sector ociently to permit contacts 52 distance between the permanent magnetand #2 eieotromagnet of the track magnets, as hereinbefore described. Consequently the holding circuit o relay 25 is broken and it therefore becomes deenergiaed as previously explained.

On passing over the electro-magnet #2, the inductor armature 105 is restored to its initial position, out as 25 is deenergized at this time, its contacts for holding magnet 4i) energiaed independent of the indue-tor armature are open and therefore, magnet 4o is now deenergleed also.

. multaneously with the deenergisation of magnet the clutch magnet 59 is energized over circuit extending fr .n ground, through the inductor armature 105 in its initial position, conductor '75, contacts 2., oi" relay 25, and contacts 37 of relay As previously explained, the operation oi the clutch magnet 59 pivotally secures the link 'I0 and the connected armature 46 oi magnet 40 so that the armature and the arm G5 controlled by it through the medium of lever 59 will he gradually lowered at a rate dependent on tlie position of the link with respect to the oi the surfaces 51, as previously described. lf now the engineman reduces the speed of the train suiciently to prevent the speedometer disk 53 from opening the contacts 52, no automatic application will be made, but if he fails to do so the circuit of the EPV magnet 22 will be broken, which, as previously explained Will cause the service brake application to be made after a second interval.

t may he mentioned at vthis time that the whistle W will be operated during the six second period, and therefore, if the engineman is alert he will he able to reduce the speed of the train and prevent any automatic hrake application taking place. On the other hand, if he fails, at the termination of the six second interval valves i5 and 1S will be moved to their alternate positions and the brakes will automatically be applied.

Since at this time the high speed relay 25 is deenergized and zero contacts 31 are open, the only path over which ground Was being supplied to the EPV magnet 22 was through the valve contacts '71 Which also opened when the 4Valve operated; therefore, the brake application Will he made regardless oi any act on the part of the engineman and there is nothing he can do but Wait until the train has come to a stop. When this occurs, the Zero contacts 81 close and a circuit is reestahlished for the EPV magnet, (contacts 52 having closed as soon as the speed of the train was reduced) the chamber 19 again builds up to full reservoir pressure and diaphragm 17 closes` valve 18 which releases the air pressure in cylinder li to atmosphere and permits the engineer to restore the engineers brake valve running position.

Since nothing has occurred as yet to restore the arm 65, and its associated contacts 52 to their maximum position the engineer must keep the speed of the train Within a limit determined by the location of these contacts which may be in an intermediate position at the time the train is brought to a stop. These contacts will of course continue to inove downward as the train proceeds through the remainder of the block.

' The amount of speed reduction necessary to prevent an automatic brake application occurring While passing through a caution block is such that at the end of the block the train will be under what may be termed, low speed control which is, say a speed of 20 mph. Trains upon entering blocks at the end of which a permissive stop signal is displayed, can pass the signal at the prescribed low speed providing proper acknowledgement is made. As illustrated in Fig. 6, when a signal of this character is encountered the associated #3 electromagnet is energized. This magnet is placed a distance from the permanent magnet suiiicient so that, after the armature 105 is moved to the right as a result of the inductor passing over the permanent magnet trackway element, the train will travel a distance which suliices to rotate the sector 48 until it again drops and its teeth 49 engage the driving pinion. When this occurs the armature 47 drops sufficiently to open its contacts 43 causing the caution relay 33 to Ybecome deenergized as Well as the high speed relay 25. The braking magnet 40, accordingly, deenergizes as it did under cau tion conditions; but sincethe relay 33, in dropping, opens a point inthe circuit of clutch magnet 59, the armature 46 drops the speed control arm 65 immediately to its low speed position, opens its contacts 45 and closes its contacts 44. An instant later the energized #3 electro-magnet is encountered and the inductor armature 105 isY deflected from its alternate to its initial position, but the operation of magnet 4l cannot at this time cause the restoration of the caution relay 33 or high speed relay 25. The reason for this is that relay 25 can only be reenergized 'through the armature 105 in its alternate position, while re- "lay 33 can only be energized through normally open contacts of the acknowledging key K. vThe relay 25, it will be noted was already deenergized v due to the previous caution block. The caution relay 33 upon becoming deenergized, opens the l circuit of the EPV magnet 22 at contacts 35, with the result that the whistle W is sounded. At this time in addition to the whistle the relay 33 at its contacts 34 completes the circuit of the acknowledging bell AB, causing-it to warn the engine- Liman that an automatic brake application can only be avoided by his operating the acknowledging key K within the usual six second interval. Upon operating the key, its make contacts again completethe operating circuit of the caution re- -lay 33, which locks up as before.

Yso that it is absolutely necessary that the acknowledging key be immediately restored after the operation of relay 33, otherwise the brakes will be automatically applied. It will be noted that relay 33 in operating at contacts 34 cuts oif .signal AB which serves to warn the engineman that it is time to release the key K.

After acknowledging, the train may continue at low speed, but the engineer must operate the key K at every subsequent permissive stop signal encountered.

" and actuation or the acknowledging key will be of no avail. The train must now be brought to a stop before the circuit of the caution relay 33 can be again restored.

When the train is finally brought to a stop 'the zero contacts 104V will be closed and a circuit will be completed from battery through these contacts, conductor 73,4 contacts 33 of caution relay 33, conductor 72 and through the reset coil 124 associated with the inductor contact and ground. The direction of current through this coil is such that the inductor armature 165 will be restored to its initial position, with the result that the grade selecting magnet 4l is again energized and its contacts 42 and 43 are again closed.

The action of the reset coil in conjunction with the zero contacts 164 is the same as that which occurred when the inductor passed over an energized #3 elect1omagnet, and the circuit of relay 33 having been prepared in this manner, the acknowledging key K may now be operated to restore the circuit of this relay so that the EPV magnet 22 may again be energized and the brakes released. After the brakes are released the train must proceed at the low speed until a set of magnets preceding a block at clear are encountered. Irrespective or" traffic conditions in the block next encountered the permanent magnet inductor will be eiective to actuate armature to its alternate position, resulting in the reenergization of high speed relay 25 and the consequent reenergization of magnet 40. The armature 46 and speed control arm 65 are accordingly restored, but whether they remain so restored, are lowered under control of the train movement, or are dropped again to low speed po sition depends on the clear, caution, or stop condition of the block in advance, as interpreted by the condition of the subsequently encountered electromagnets of the group.

From the foregoing it will be appreciated that the train must be brought to a complete stop before it is allowed to pass a specified distance beyond a permanent magnet in cases where none of the associated electro-magnets are energized. In actual practice the engineer may pass an absolute stop signal without having the brakes automatically applied but to do so he must move toward the signal at a very slow rate of speed so that he can stop immediately within the six second period so that the zero contacts 104 will be closed before diaphragm 17 of the electropneumatic valve collapses.

From the foregoing it will be seen that a brake application due to exceeding the maximum speed limit may be released by reducing the speed to its normal maximum rate illustrated as being 65 mph., but an application caused by overrunning the braking curve or passing stop signals without acknowledgement can only be removed by bringing the train to a standstill. Furthermore, when it has once been brought to a standstill the train can only proceed at low speed up to the next indication point, where if the #l electro-magnet is energized, which indicates a clear condition the train can resume normal running.

An explanation will now be made of the operation of the lamp signals in the cab. During normal running through clear territory the high speed relay 25 remains energized and the green light G will be lighted over a circuit including contacts 36 of this relay, conductor 67, and contacts 45, to indicate that the traillc conditions are clear. When a caution block is entered and the high speed relay 25 is deenergized, the green light is extinguished and the yellow or caution light Y is immediately lighted due to the opening of contacts 30 and closing of contacts 3i. This circuit it will be seen also includes conductor Sl and contacts 4R. When the speed or" the train has been reduced at the end ci the caution Telcel; the armature i6 ot magnet 40 is at its lowermost position, at which time the circuit of caution light Y is broken at contacts i5 and a circuit is closed through the alternate contacts ed for the red or danger lamp signal R. These various lamp signals taken in conjunction with the audible signals and brake indicator hereinhefore referred to inform the engineer at all times under what condition his train is being operated.

In a train control system wherein the train control mechanism is operated through power transmitted from a wheel of the locomotive it is important that some provision be made to guard against the locomotive being taken out on a run when the connection between the train control equipment and the wheel or" the locomotive .is broken. This has been accomplished in the present case oy providing the torque detector, previously hrieily rei'erred to.

The iiexihle speedometer shaft 88 from which the train control equipment is driven is connected to the wheel of the locomotive through a unit comprising a sliding spring coupling carrying a disk which is normally raised when the torque is applied to the speedometer shaft. When no torque is applied the disk is forced downward by the spring 83 and breaks a pair of contacts 80, causing the deenergization of magnet 82. This allows the geared sector Se to fall into engagement with the worm 9i.. if new engine is in motion, sector 94 will be rolled out of engagement with 91 and the contacts 9S, which supply battery current to the EPV magnet 22, will open to cause a brake application. Under normal circumstances, of course, the train may come to a rest Without opening contacts 95, oecause the aXle comes to rest at the saine time that torque is removed from the unit.

It will be noted that the permissive speed indicating arm is shown in a 'position with respect to the speedometer disk to indicate a permissive speed of 'l0 mph. A passengr train traveling through a 4090 foot block, under caution con-- ditions, with a permissive speed as indicated i ill cause the arm to he lowered from 70 to 2O in the 4900 foot distance oi travel. Now if a freight train passes through this same block under the same conditions, except that its permissive speed indicating arm is positioned to indicate a inanimum of 40 miles per hour the arm 65 will 'oe lowered from 40 to 20 in the i996 foot distance of travel due to the change of position of the fulcruin of 65. From this it will be seen that the braking curve for any vehicle is accurately enforced irrespective of its maximum permissive speed.

From the foregoing it will he appreciated that applicant has devised a train control system which is practical, and requires very little equipment compared to that required by other systems accomplishing the same results.

What is claimed is:

l. In a system of vehicle speed control, in combination, a movable speed control element, and magnetic means placed intermittently along the path of travel of the vehicle for varying the speed at which the element moves with respect to the speed of the vehicle.

2. In a system of vehicle speed control, a locomotive equipped with sT eed controlling mechanism which includes an operating element whose rate of movement determines the extent or" the speed reduction curve, a traclnvay forming a path over which the vehicle travels, said trackway divided into block sections oi varying lengths, and permanent and elcotrcmagnets associa-ted with the tracliway in the exit portion oi each block section for eter-mining the speed reduction cufve `for the suc ceding section.

3. ln combination with a locomotive and a tracl: over which the same travels, normally inacspeed control mechanism for the locomotive,

inductive traclrway elements distributed along the trackway eirective as the locomotive passes them to cause the speed control mechanisin to operate at various rates of speed with respect to the speed ci the locomotive.

l. a system of vehicle speed control, a speed controlling mechanism including an operating element, v le speed driving means for said element, faclrway magnet means in inductive relation to vehicle carried means for regulating the of the eiement.

5. In system ol vehicle control, speed controlling mechanism including a normally inactive operating cam, in combination with a vehicle and trackway ior the saine, a system or" controlling equipment in part associated with the vehicle d in part associated with the ip dent associated with the vehicie includingnie-ans ior itting the vehicle to travel through all track sections, at the same maximum speed at one time and for requiring the vehicle to pass through the saine sections at cc istantly reducing restricted speeds specially characteristic o1c such sections at another time, ed 'pment influenced inductively by the equipment on the tracltway at Jhe exit of the section n manner dependent upon the condition of a succeeding tracl vay section.

ln combination with a vehicle and an assotracliway, a movable permissive speed device, and permanent and electromagnets intermittently along the traclrway for controlling movement oi the permissive speed device at varying rates of speed with respect to the speed oi the vehicle.

.7. In a system of control for moving vehicles,

normally inactive means for retarding the movement oi" the vehicle, a permissive speed indicat r, an actual speed indicator, one of the indicators being normally inactive, inductive mcansplaced in the path or" travel of the vehicle for cau g the movement of the normally inactive indicator to occur at a inte depe dent upon the spacing of sai inductive means, ano means controlled by the movement of the inactive indicator to a predetermined relation with respect to the other indicator for causing the operation of the retarding means.

8. A system of ti i control for moving vehicles `"iclufong a io "rally inactive means for .i l 5 or the vehicle, a normally active actual speed indicator, a normally inactive permissive speed indicator in the path or movement of said actual speed indicator, it ons for causing the movement of the permissive speed indicator', means controlled by the ...ioveinent ci the actual speed indicator into engagement with the permissive speed indicator while the same is inactive to the operation or the retarding means until the actual speed indicator moves out or" the predetermined relation with the permissive speed indicator only,

with the maximum speed at which the vehicle is to be permitted to travel, and means for operating the device at a speed contingent partially upon the initial position oi the device.

20. In a system of control for moving vehicles, a normally inactive `permissive speed indicating device, means for varying the initial or normally inactive position of said device so that the same may be set to indicate any of a number or' desired maximum permissive speeds depending upon the character of the vehicle to be controlled, and means for driving said device from its initial position to the san e predetermined loW speed indicating position by the same distance of movement of` the vehicle irrespective of the initial setting of the speed indicator.

2l. In a system of control for moving vehicles, a permissive speed indicating arm, saidarm being free atone end and pivoted at the other and supported at an intermediate point by means for causing the arm to indicate a continuously diminishing rate of permissive speed for the vehicle, means for lowering the support of the arm at a certain rate With respect to the-rate oi movement of the vehicle, and means `for changing the fulcrum of thev speed indicating arm to various points 0i contact with the leverk to vary the rateoi movement of the indicating lever With respect to the same rate oi movement or" the vehicle.

22. In a system of train control, a speed indicating lever pivot'ed at one end and supported at an intermediate point by'an element for lowering it, means for changing the ulcrum of the lever from one point to another to change the maximum permissive speed indicated by itv and to changethe rate of movement of the lever from one point to lanother vvitlirespect to th rate of movement oi the element.

` 2.35111 a system of train control, a lever pivoted at one end and equipped with a permissive speed indicating arrow at the other end and supported at intermediate points by an element for lowering the indicating lever, means for changing-the fulcr'um of the lever from one point to another to change the maximunipermissive speed indicated by the connected arrow and to change the rate of movement or" the lever from one point to another with respect to the rate of nievement of this element and means Y'for varying the rate of movement of the element with respect or^ movement of thevehicle.

2li. In a system of speed control for vehicles,

an inductor consisting of an armature biased to either of tWo positionsto which it may move, and trackvfay elements fo1- inductively'influencing said inductor to thereby operate its armature in a manner dependent on traic conditions, and manually controlled circuits on'the vehicle for also iniluencing said inductor under certain conditions.

25. In a system of speed control for vehicles, an inductor consisting of an armature normally biased to either of two positions,'tracl :way elements inductively related to said inductor 'to cause the same to be operated, a series of track'- Way elements consisting of a permanent magnet and three electromagnets, the permanent magnet being eiective to move the armature to its alternate position to start the functioning of the speed control equipment, and track circuits' for energizing one of the electromagnets to further influence the equipment in a manner depend-` ent on traffic conditions. Y 26. In combination With a'vehicle andan associated trackway divided into varying length sections, of-train control equipment partly on the vehicle and partly on the trackway, the tracliway equipment comprising a permanent magnet `and two electro-magnets placed longitudinally of the trackvvay at the exit of each section and of a third electromagnet placed at the entrance Vof the next section;y and the vehicle equipment consisting oran actual speed indicator, a permissive speed indicator and associated mechanism ior regulating the movement oi the vehicle in accordance with traffic conditions, and an actuator on the vehicleconsisting of an armature normally biased toene position by a permanent magnet but deflected to an alternate position when the vehicle brings it into inductive relation to a traclcway permanent magnet and restored by one of the energized electro-magnets to control the equipment on the vehicleV for the purpose set forth.

27'. In a system of vehicle control, a governor, means including a sliding spring clutch for transmitting motion from the axle of a vehicle to the governor, a normally energized vehicle control magnet eiective, when deenergized, to cause the speed of the vehicle to be reduced, a relay having Working contacts through` Whichthe circuit or" said vehicle controlmagnet circuit passes, mechanical means for'normally` holding saidcontacts closed when the vehicle is ata standstill but ineiective after a vlimited distanceof movement, and a circuit for :said relay extending through contacts closed by the driven portion of said spring clutch to maintain said relay energized and the retarding magnet circuit closed after the mechanical means becomes ineffective to prevent the operation of the retarding means, unlessthe governor drivingV means fails.

23. In a systemof vehicle control, speed control equipmentpartly on aV trackv/ay divided into sections and partly `on the vehicle, retarding means on the vehicle, a controlling magnet havinga circuit for maintaining it operated to prevent the retarding means becoming effective, `a

i permanent magnet at the exit end of each trackafter the vehicle has traveled a certain distance Y irrespective of its speed, and an electromagnet for transmitting a second impulse to said pickup relay priorjto such distance oi travel to render the effect of the rst impulse ineffective.

29. In a system of vehicle control, speed control veduiizunent partly on a trackvvay divided into sections and partly on they vehicle, retard- -ing means on the vehicle, a controlling magnet to be held intact as long as the speed of the ve-` hicle is kept under a constantly diminishing 'indicated permissive speed.

i 30. In a system ofvehicle control, speed control equipment partly on a trackway divided into sections and partly on the vehicle, retarding Ameans onthe vehicle, a controlling magnet having a circuit for maintaining it operated toprevent the retarding means becoming effective,

LGI).

meansV at the exit end of each trackvvaysection for transmitting and on the vehicle for receiving an impulse to cause said circuit to be opened only after the vehicle has traveled a certain distance irrespective of its speed, means for transmitting a second impulse to said receiving means to cause the circuit of said magnet to be instantly broken, and manually operable means for restoring said circuit before the retarding means can become effective.

31. In a system of vehicle control,` control equipment partly on a trackway divided into sections and partly on the vehicle, retarding means on the vehicle, a normally closed controlling circuit for preventing said retarding means from being actuated, a permanent magnet at the exit of each sectionA for transmitting and `a polarized magnetic device on the vehicle for receiving an impulse to cause said circuit to be thereafter preventing interrupted, means for said retarding means from being actuated for a predetermined interval of time, and means for again. actuating `said polarized magnetic device to reclose said circuit prior to the expiration of said interval.k

V32. In -a train control system,\ a normally stationary element, Va second `element operable at a speed determined *byV said first element, a third element for operating said iirst and second elements, and means for causing the operation of the second element to occur only after the speed of its operation has been determined by an appropriate movement of the first element by said third element.

33. In a train Y control system,4 a normally stationary element, a second element operable at a speed determined bysaid rst element, a

third element for operating said first andv seclond elements, and means forcausng the operation of tlie second element to occur after the lspeed of its operation, with respect to a given speed of lmovement of a vehicle, has been determined by an yappropriate movement of the firstV element by said third element. f

Y34:. In a system of vehiclecontrol, speed control equipment partly on a trackvvay divided into sections and partly on the vehicle, retarding means on the vehicle, aV controlling magnet having acircuit for maintaining it operated to prevent' the retarding means `becoming effective, means at the Vexit end of each trackvvay sec-.- tion for transmitting and on the vehicle for receiving anV impulse to cause said circuit to be opened only after the vehicle has traveled a certain distance irrespective of Yits speed,` means for transmitting a second impulse to said receiving means to cause the circuit of said magnet to be instantly broken, and manually operable means for restoring said circuit under either circumstance, before the retarding means can become effective. f

35. In asystem of vehicle control, speed control equipment partly on a trackvvay dividedinto sections and partly on the vehicle, retarding` means on the vehicle, a controlling magnet having a circuit for maintaining itV operated to prevent the retarding means becoming effective, means at the exit end of each trackway section for transmitting and on the vehicle for receiving an impulse to cause said circuit to be opened only after the vehicle has traveled a certain distance independent of the vehicle speed, means for transmitting a second Yimpulse to said receiving means to cause the circuit of said magnet to` be instantly broken and manually Operable means.

for restoring said circuit under either circumstance, before the retarding means can become effective.

36. In a train controlapparatus, the combination with a valve device operated upon a reduction in fluid pressure for effecting an application of the brakes, and electrically controlled means adapted upon deenergization to vent fluid pressure from said valve device, of means operated by the venting of fluid pressure-from said valve device for opening a circuit through which said electrically controlled means may be maintained energized.

37. In a train control system, an electropneumatic valve, a vehicle. speed governor having contacts controlled thereby included in an energizing Acircuit for said valve, means for selectively determining at what vehicle speed the governor will bring about the opening of said contacts, brake controlmechanism set into operation to apply the vehicle brakes consequent to the deenergization of said `electropneumatic valve, a second pair of contacts operative coincident With an automatic brake application, a set of manually operative contacts one pair of Which are included in said circuit, a control circuit including another pair of contacts of the set and an acknowledging magnet controlled thereby to forestall an initiated automatic brake application, only if operated beforefsaid second pair of contacts have operated.

38. In a train control system, an electro-pneumatic valve, a circuit normally maintaining said valve closed Vto 'prevent a brake application, means for automatically opening said circuit, means ior delaying the brake application taking place for a predetermined period of time after the circuit is opened, and a manually operable acknowledging lever operated to cause the reciosure of said circuit before the expiration of `said predetermined period of time and operated to cause the closure of said circuit after the prede.- termined period has expired only if the train has come to a complete stop.

39, In a train control system applied to a rail- Way system having its trackWay divided into blocks, a pair of cab'carried signals, means for actuating said signals at the exit of a block when the traffic `conditions ahead are unfavorable, manually controlled means operable to retire only one of said signals, and means for temporarily preventing the retiring of said one signal after the expiration of a definite interval of time following the first change.

,y 4Q. Ina train control system, vehicle carried visual and audible signals together with apparatus vfor controlling therbrakes of thev vehicle, pairs of trackway magnets spaced at points along the trackway for transmitting controlling iniiuences from the trackvvay to the vehicle, a relay carried by the vehicle responsive to said influences to variably change the condition of said signals and to initiatejthe operation of said brake controlling apparatus and means for manually changing the condition of only one of said signals and for preventing a brake application occurring under certain conditions.

All.v In a train control system, a normally energized electro-pneumatic valve for normally preventing an automatic brake application occurring, means for causing the magnet of such valve to become` deenergized, means for delaying a bralerapplication occurring for a denite interval after the deenergization of such magnet occurs, and a cab carried readily accessible manucontrolling the said magnet and signals, and anacknowledging contact set for controlling said relay.

43. In the vehicle equipment of a. train step system, an automatic brake Valve, a magnet normally energized to prevent said brake valve from functioning, three cab signals for indicating trafc conditions, a relay operable by magnetic impulses transmitted from a source exterior to the vehicle for'controlling the said magnet and signais, and an acknowledging contact set for also controlling said relay;

ALFRED ERNEST HUDD.

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