US1478101A

US1478101A - Dualistic cab signal and automatic train-control system

Info

Publication number: US1478101A
Authority: US
Publication date: 1923-12-18
Anticipated expiration: 1940-12-18

Description

Dec.f18 ,1923.

J. w. Bul-:LL

DUALISTIC CAB SIGNAL AND AUTOMATIC TRAlN CONTROL SYSTEM 3 Sheets-Sheet 1 Filed Sept. 14

Dec. 18, 1923. 1,478,101

J. W. BUELL DUALISTIC CAB SIGNAL AND AUTOMATIC TRAIN CONTROL SYSTEM Filed Sept. 14 1921 5 Sheets-Sheet 2 Dec. 18 1923.

J. W. BUELL DUALISTIC CAB SIGNAL. AND AUTOMATIC TRAIN CONTROL SYSTEM 3 Sheets-Sheet 3 A vvvvvvvvvvl Filed Sept. 14

Patented Dec. 18, 1923.

UNITED STATES PATENT OFFICE.

JOSEPH WHITMAN BUELL, 0F IVASHINGTON, DISTRICT OF COLUMBIA; WANDA A. BUELL, EXECUTRIX OF SAID JOSEPH WHITMAN BUELL, DECEASED, ASSIGNOR TO BUELL SIGNAL AND TRAIN CONTROL COMPANY, INCORPORATED, A CORPORATION OIF VIRGINIA.

DUALISTIC CAB SIGNAL AND AUTOMATIC TRAIN-CONTROL SYSTEM.

Application led September 14, 1921.

To all whom t 'may concern Be itl known that I, JOSEPH VHITMAN Buma., a. citizen of the United States, residing at the city of Vashington, in the District ot Columbimhave invented certain neiv and usetul Improvements in a Dualistic Cab Signal and Automatic Train-Control System,"ot' which the following is a speciiication.

This invention relates to a dualistic cab signal and automatic train control system, that contemplates combining the general type ot' system disclosed in reissue patent, numbered 14,676, dated June 24th, 1919, with that type oit system disclosed in my (fo-pending United States application for Letters Patent, serial numbered 452,695 and tiled March 16th, 1921.

Before dealing with or describing the actual system and apparatus, a good deal of ground will be cleared if certain aspects ot the invention are first dealt With in more or less general terms.

In order tounderstand the nature and scope ot the present invention` with reference to its i'uiulamental characteristics, it will first be considered in relation to the principle of arrangement ot the circuits andl control elements, as a means ot eiliecting a true combination.

In this general class o'' devices, it necessary to employ onl a locomotive, an electroniagnet governing means for controlling a signal giving device and normally holding closed an air vent in the brake system, as long as current `flows through said magnet and upon the failure tliercot to cause the production ot a signall and the application oi the air brakes.

One ot the main olljections to the employmeut ot a singin system. oit contrivances a s magnet 'rovcrning means and the tract,v apparatus its control and operatimi, has been that vfhen one of the members oi: they system becomes deranged it necmirily incapacitates the whole systoiu and a locomotive thus equipped has to proceed throughout the rest ot its run with sole reliance on the roadside signals.

The present invention therefore contemplates multiple control and operation ot the magnet governing means, by the establishment and interruption of the current conditions,

Serial No. 500,673.

flowing through said magnet by reason of the joint control or effect of a composite or duplicate means that is interposed between said magnet and the respective track circuits encountered.

To the end of providing `a dualistic or composite system, one branch ithereof is arranged in operative relation to said electro-magnet and comprises two normally inter-linked circuit members, Working on the closed circuit principle, one ot' which includes said electro-magnet, While the other is brought into direct union With the all rail track circuit for control thereby at tratiic control points,V said control being et- :t'ected in this branch ot the system by the introduction and Withdrawal of a point of resistance, in the track connected circuit, under the iniuence' of a safety shunt controlled by said track circuit.y

The other branch of said rdualistic system contemplates the employment ot' a controlling and operating apparatus, in which one clement comprises a comparatively slow acting mechanically operated means, such as a circuit breaker, controlled in its movement by a shoe engaging with a ramp, and which serves to positively interrupt the above mentioned circuits at such points, every time said circuits pass those points, were, provision not made, under safety :tor introducing momentarily into the combination, a normally incoluplete circuit by closing the same under the influence oi? ay second safety shunt and the controlling track circuit, to quickly ei'l'ect a shunt or compensating pathway across those portions ot the interlinked circuits about to be broken by the mechanically operated means, to thereby preserve the in-y delay.

ggg nec/arci By reason of such a principle of circuit and control arrangement there is provided a true combination that secures the most perfect mutual dependence or the means involved, as well as alfording a two-fold plan of control and loperation both on the locomotive and the track at trafhc control points, that acts on a common mechanism, to wit, the electro-magnet governing means and which is governed by the control ot a given track circuit.V

The objection ordinarily offered to the employment ot an open circuit means in this art, is that a broken `conductor might continue undetecteifl and result in a danger giving condition. ln the present invention, however, in that branch of the system employing a normally open control circuit provision is made in toe event of a conductor thereol.3 becoming broken, or' relying upon the mechanically operated means or circuitbreaker for producing a danger indication and the application of the brakes, thereby revealing the failure or' 'the broken conductor on the side out safety.

F or the successful employmentot duplicate electrical means or agencies on a loco'- inotive, it should be designed so that the derangement of one circuit member will not cause the derangernent of the other circuit member, while both should be protected 'from injurious effects due to a clgrounding7 of the head-light circuits on a locomotive.

Therefore it is a further object ot the present invention to so combine `he co-ordinate circuit members ot the system, by making one oit them normally activo., while the other remains inactive until it reaches a traffic control point, where under `rtety conditions, it is rendered active but ii'or the moment, so that in the event ot one ot the circuit members becoming grounded7 it cannot dangerously atleet the other circuit in inber because the fugitive current therefrom would simply reinforce that oit the other circuit member and aid in. its tunctimiing.

A li'urther object of the present invention is to increase the i'irecautionary measures tor safety by providing on tour occasions, in a given block or section, 'for Athe transmission from the trackl oit' a control or opel"- ative impulse to the apparatus on the locomotive, in accordance with the condition ot the block ahead, as well as provi ding under danger conditions .for the reduction of speed and gradual. stoppage of the train, by inaugurating a progressive service application of the air brakes within braking distance of the block ahead and continuing the brake application in the manner or natural order that would ordinarily be followed by an engineer in the face of danger.

It is further an object of the present invention to depend on electric per-,ver that comprises two traveling sources of electric energy, carried by the locomotive; the current from said sources may or may not dii"- ter in character, and 'to that end to employ a low voltage source of electric current, as a small storage battery in connection with one portion of the dual system, and limiting it to its proper and economical field ot useiulness in supplying current to low voltage signal lamps and electro-magnets, and to utilize, intermittently and n'ioinentarily, in the normally inactive circuit member, under sa'liety conditions, when it is completed, a higher ,f'oltage current, that is preferably furnished by the head-light turbo-generator, upon such occasions, thereby reducing` with vast economy the cost ot the power liact r, over the plan that depends upon current collection from track sources, at every block section along the line.

Electrical apparatus carried on a locomotive is subjected to heavy and vibration and the electrical conductors employed in conduits thereon do not have sutlicient insulation strength to withstand the wear due 'to the effects of and vibration, for any great length ot time.

further object of this invention is to provide a suitable and reliable means tor revealing the insulation breakdown and grounding of conductors in any circuit eniployed in this system, which is a matter olli vital concern in a system ot this kind.

Another obj` ect ot the present invention to provide a system having the above; noted characteristics, which shall, while being` relatively simple as regards its parts and their arrangement, require but small cost to install and maintain it in operative condition, while at the saw ie time it is certain and positive as regards its operation.

Those objects and tentures olI my invention which have not been particularly and separately mentioned in the it'oregoing preamble will clearly zuipear in the lig; olt he iollowii'igi; more detailed description oli my invention embodied in the combined subsystems, which l have illustrated in the accompanying drawings.

As the present descrii'ition ot the dualistic system of train control does not relate so much to the structure ot the operating` mechanism as to the organization and inauucr ot control ol the circuits involved, such means will be mostly shown diaerammatically in the accompanying drawings.

llelierring to the drawingsfllliguro l, is a general circuit diagrann illustrating both circuit members oit the composite system united in workingr relation to each other, when brought into operative relation with a trailic controlling point.

Figure 2, shows an enlarged and detl vierv of coils 'lL-8, of the magnet gever means, and the circuit connections thereoflull E rig Figure 3, illustrates diagrammatically one form 'of track equipment required at the home and approach points, respectively, on a double track line.

Figure 4t, shows a modified form of track equipment.

Figure 5, illustrates the structure provided in the truck insulation and the circuit arrangements depended upon to reveal insulation breakdown in the truck insulation and that of the conductors leading thereto.

Figure 6, shows an enlarged view of coils 7 8, of the governing magnet, illustrating the manner of employment of a second armature thereon for revealing failure of coil 8.

Like characters of reference indicate corresponding parts in the several figures, while the arrow in Figure 1, shows the normal direction of traffic for such an equipped line.

The purely electric branch of the dualistic system, constituting the instant. invention, is generally the same, structurally and operatively considered, as that described in the reissue patent aforesaid, and may be briefly described as follows:

Referring to Fig. 1 of the dawings, 1", r represent the rails of the track, which is divided into sections or blocks by the usual insulating joints y', j', each section including a source of current T, bridging the rails at the remote end, and a relay TR bridging the rails at the entrance or near end oli the section, each relay being normally energized and the armature thereof closing a loop w, w', of negligible resistance. bridging the insulated joints between the rails of adjacent blocks or sections. As indicated, the current Supply for the track circuit of each block or Section comprises a transformer T connected with mains TL, which supply alternating current from a `generator or generators located conveniently to the roadway, thereby eliminating the trouble and expense of maintaining local track batteries in cach block.

Mounted on the locomotive are the control and working circuits, with their appropriate translating devices, supplied -from acommon battery 6, 'the control circuits; having coils 7 and S of the differential relay DR, which latter controls the working circuit, being indicated by reference let` s and B, respectively: the working circuit, iu-

cluding the valve holding magnet VHM, isv

represented b v reference letter C; and the signal` or indicating circuit by D, the several circuits A., B, C and D being connected in parallel 4with common battery 6 carried by the locomotive.

Circuit A starts from the battery 6 and passes -bv way of wire 6*, loop wire Z, circuit braker B, loop wire Z, wire Q3 to forward truckFT, rail r, loop fw, ce', including ar! mature ofrelay- TR, rail 1 ofpreceding block, rear Wheels A2 to the frame of the locomotive, indicated by dotted line A3, to conductor f grounded on the engine frame at fc, coil 7, wire 24, and wire -back to the battery 6. This particular circuit is effective when the forward insulated truck FT is entering one block, such as X, and the other wheels of the locomotive occupy the rails in the preceding block, such as Y, when the forward block X is clear. lVhen the locomotive iswholly within a given block and the latter' is clear, the circuit A will be closed between the insulated forward truck FT and the driving wheels of the locomotive by way of the rails r, r', as will be understood.

The circuit B is follows: battery 6, wire 6*, wire 20, including normally closed push button pb, coil 8 of relay DR, wire 22, and wire 6--back to the battery. A loop in this circuit, around the push button pb, formed by wires Cs and C, includes an air operated circuit breaker 92, controlled by the air release during the application of the brakes and also the contacts of a speed governing means 95 to effeet the required reduction of the speed oit the train after the air is released, before the system may be restored, by operating the push button pb.

Circuit C, which controls the valve holding. magnet VHM, is from battery 6, wire 6*, loop wire Z, circuit breaker CB', loop wire il', wire 13, stationary contact 10, armature Contact` 9, armature 12 and frame l2 of relay DR, wire 19, coils of valve holding magnet VHM, in parallel, wire 14, resistance R', wires 15 and -back to the battery.

'The circuit. D, which energizes the electric lamps L, or equivalent signalling or indicating apparatus` includes wire 6*, wire 1S, lamps L, in parallel, wire 16, resistance R', wires 15 and G-to battery 6.

The system, as thus far described, is generally the same as that of the reissue patent aforesaid' in structural arrangement and mode of operation, the only'material variations therefrom being the inclusion of the loop wires Z, Z. and the normally closed circuit breaker CB in the circuits A and (fl, aud the loop (lg, C'l around the push button p7) in circuit B, which latter controls coil 8 of relay DR. which loop includes the air operated circuit breaker 92 and the speed governor controlled circuit breaker 95, which two circuit breakers prevent the reenergization of the coil S andL the restoration of the system by the engineer operating push button pb, until the air brakes have been. applied and the speed of the train reduced to a predeterminedL point.

In the diagrammatic illustration of Fig. 1 vof the drawing, the locomotive is shown as entering an unoccupied blockV` or section: X,

ture l2 will be attracted by coil 7 and the circuit C will be interrupted contacts 9 and jlU, thereby deenergizing the valve holding magnet, ctfecting an application 0i: the brakes and the r 'sing of the current value in the sigiial lamps L to bring them to bright incandescence.

As soon as the circuit ol coil 8 is restored, armature 12 will be immediately attracted by the core of the coil to again close the contacts 9 and 10, as the normal pull of the core ot the coil S on the arn'iature l2 will exceed the-attractive force of the core ot' coil 'i'. The deenergization ot coil 7 will `not affect armature 12, which will remain in position to close contacts 9 and 10, so long as coil 8 is energized.

As was the case in the system described in the reissue pftentaforesaid,- the resistance R in the common section or' theparallel circuits C and D is so adjusted that the lamps L will normally burn at low incandescence, thus serving as a telltale signal that gives constant evidence ot' the integrity ot' the circuits and the condition of this portion ot the system. lllhen, however, the circuit C, which controls the valve holding magnet, is interrupted, the value ot the current in circuit l) will rise and bring the lamps to bright incandescence, thereby indicating a danger condition. v

Because of the low internal resistance ot circuit A, including coil 7, and the employnicntot the bridge wire (il) between circuits .A and B, the system will func-tion reliably when the resistance in the insulated joints olI the track, or in a leakage pathway about said joints, is as low as ft/l0 or" one ohm, and long before suoli alow resistance is reached, the loop fw, w', will, by reason ol? .overlapping relation with respect to the Joint, short-circuit either the track relay TR in the corresponding block, such as or the source of electric energy in the adjacent block Y, according to which of the rail joints or y" breaks down to the mai"- ginal resistanceindicated.

ln order to limit or nullify the ei'l'ect O'lf any Yforeign direct current,flowing Vfrom one track section by way of loop fm, w to the adjacent section or block, on the track relay TR in the latter section, an impedance coil z' is bridged across the terminals ot the track relay, as indicated in Figs. l and 45.

It is obviously essential that the iront truck of the locomotive equipped with the apparatus, as Vhereinbefore described, must be carefullyl and completely insulated from the other portions of thel'ocomotive, and an effective means to this 'end is :illustrated in Fig. 5, in which FT indicates, diagrammatically, the lower center bearing casting forming' part ot the truck. The insulating means consists of a'series ot alternate'fiber cach other and in the recess inthe center bearing casting of the truck. This form of insulation may be applied readily to k'the standard types 'of locomotives 'without keeping the latter out of commission for any material length of time and have proven entirely effective under the most trying trafic conditions'. llheside'walls` 'of the liber cups I are preferably extended 'vertically above the upper edges of themetallic cups M, so as to prevent the electrical bridging 0l the cups M, M by thelodgment oi2 any foreign metallic substance thereon.

ln order to clearly indicate the dualplan oi control and operation of thecircuitsA and C, involving the insulated truck circuit on the one hand., and the ramp system-on the other, so that the two portions of the system will function simultaneously, or either will perform its normal operation in case ot failure of the other, Vthe rampV controlled portion of the system and its association with the purely electric controlled portion ot the system will now be described.

is hereinbefore indicated, the circuits A and C each include a branch or loop, com-` prising wire Z, circuit breaker CB, and wire Z, the circuit breaker serving to open and close the circuit between the loop sections, Z and Z. The circuit breaker CB" comprises a reciprocatory stem, having heads on its` opposite ends, the upper head serving to close the loop circuit Z, Z through a contact plate mounted on the support through which the stem reciprocates, the wire Z'being connected to thestationary member or plate of the circuit breaker and ther wire Z to the reciprocating stem. The movable and sta-` tionarycontacts of the circuit' breaker are normally held in contact by a helical vspring Se surrounding the stem. Likewise mounted for reciprocatory movement'and insu"- lated from the engine frame, is ay shoe S, having an upwardly extending stem de, which is normally forced downward or toward the track by means of a helical spring The shoe S s surrounding the stein (Za. is so disposed as to engage ramps, such as t, R mounted on the side of the track, which ramps have their upper or contacting surfaces of anticlinal form, so that, when the shoe engages the upper face of the ramp, it will move upwardly and downwardly in its traverse of the ramp,l thereby eli'ecting the successive opening and closing of the circuit breaker CB as each ramp is passed, the stem Za of the shoe S engaging the stem (ZZ) 4of the circuit breaker so that, when the shoe is moved upwardly the circuit breaker is moved in the same direction and when the shoe returns to its normal position, after disengaging a ramp, the circuit breaker will also automatically return to its normally closed position'.` Preferably, the

ill)

upper end of the shoe S is rated from the lower end breaker CB by a sutiicient distance to et tect a short delay between the initial engagement or the shoe with a ramp and the opening ot the circuit breaker CB. i

Preferably, each block or section is provided with two ramps R, lt, the upper conducting surface or each being connected in series with a wire TLO, one end ot which terminates in a contact Z1, which normally closed by the armature ot track relay thereby connecting ramp track loon 'ill-i5() with the rail r of the adjacent block oy way of the loop section w. I

Electrically connected with the shoe is al conductor 50, the other end ot which is attached to the positive terminal ot a source of electricity, preferably the generator G, which supplies current to the head-lightn The other terminal or the generator G is connected to a conductor, wound about the insulated conductor 50 and parailelinglj the same in a reverse loop, to constitute an in sulation lbreak-down indicator,A as will be hereinafter described, the so-called detector loop beingr indicated by wires (Z and al. The 'free end of the detector wire d is connected to an electro-magnet the other terminal of which is connected to a wire m providedL with a terminal contact n, normally engaged by the armature m ot an electro-magnet or relay TM, the other end oit said armature being grounded at G on the locomotive frame.

The circuit, as thus described, constitutes the so-called test or pick-up circuit, which is completed each time the shoe S engages a ramp, the complete circuit, under satetf-,r conditionsr` being as follows; from the positive pole ot generator G, through conductor 50, shoe S, surface conductor et ramp or R, loop TLO, contact ZL, armature oi track relay TR, track loop section w, rail normally sepaot the circuit 12 driving` wheel l2 ot' the locomotive, the ce to Athe ground G ou the trame,

armature tu, contact a, conductor m, map;- net lll, wire (Z, paralleling coiuhictor 5i). thence through the convolutions ot w' (Z back to the negative 'terminal ot the i; erator G; the closure ot this pick-up cr test circuit is oi relatively short duration, depending upon the time of. contact between the shoe S and the surface of the ramp. Obviously, instead ot makiincr the return connection 'from the magnet E to the neger tive terminal of the generator G through the so-called detector loop (Z, (Z, the indicated terminal oi the magnet E may be directly connected. tothe negative terminal ot' the generator. t will be noter that the completion ot this test or pick-up circuit is dependent upon the condition of the track relay TP. in the block ahead. lhould this block be occupied and the track relay TR short-circuited, the test circuit aforesaid will be interrupted at the Contact Zi.

'fihe principal function ot the test or pickA up circuit is to cause the armature is; ot the magnet ll to assume or maintain the same relation the armature ot the t TR. in other words, vhen the arnrwure ot the track relay Tit is attracted. and the track loop circuit fw, w closed, and the test or pick-up circuit is closed by the shoe engaing a ramp, electro-magnet pick up or attract its armature l., f closing a circuit from battery 6 through wire Zc, including normally closed push but ton pb, lamps L in parallel betn'ee-LA sections ot' wire Z0, coils ot a ma thence through a holding magnet n' series with TM, thence to a spring contact ZJ, armature l, wire 0, back to the battery. it will be noted that the armature r operates with the cores ot magnets E i so that, when the magnet lll attracts :irmature li, i. simultaneously closes the circuit through the holding` mag et F and this latter magnet holds armature h. in its closed position until the circuit is subsequently interrupted by operating the push button git. rl-Vhe closure oit this circuit through the mac;- net F also energizes trip magnet Thi?, which attracts its armature a and breaks the pick up or test circuit at contact a, thereby corr serving' the current from the generator G,

The purpose ot the pick-up or test circuit is to determine, first, by a conductivity test through the track loop T1150, the condition of the track circuit ahead and also to pic-l up the armature lever K and raise it to safety position, under safety conditions`- by the momentary flow ot current lrom the generator G through said circuit,y second, to close the holding` circuit through magnet F and simultaneously break the test circuit by the operation ot trip magnet TM, and third, to close a shunt circuit to the loop Z, Z. included in circuits and C, which latter include the coil oi' the dill'erential relay and the valve holding' magnet "Jlil'ii respectiif'ely, said shunt circuit including wire s connected to loop section Z, linger t to arma-- ture l, contact c2 cooperatingi with said finger, and wire 82 connected with loop section Z. This shunt circuit to the loop Z,y Z, is closed before the circuit breaker is actuated and, therefore-r serves to preserve the integrity ot the circuits through the coil 7 ot the diiierential relay and through the coils oi, the value holding; man-net, when said circuits would otherwise be interrupted by the circuit breaker CB when the latter is operated by the shoe S engaging a ramp to break the loop Z, Z. V

The operation ot the ramp section et the syst-em is as follows: lWhen the shoe Si engages the ramp lt in block Y and bloei' A is clear, the iirst effect is to close the pick- Lll) ini

up or test circuit between the shoe S and the surface of the ramp by way of test loop TLO, contact Zz., track loop section fw', rail r, wheels A2, and frame of the engine, to ground at G' thereon, etc., as hereinbefore described, thereby closing the shunt s, s2 about loop Z, Z' and circuit breaker CB' before the latter interrupts the circuits A and C at the loop Z, Z'. This produces no change in the normal relation of the coil 7 of relay DR and the valve holding magnet VHM, but causes the lighting of the lamps L to indicate that the circuits and apparatus of the ramp section are intact. The engineer breaks the circuit from battery 6 through the holding magnet F at push button pb', thereby releasing armature K and lneaking the shunt s, s2 to loop Z, Z'. These operations are repeated when shoe i. engages ramp R, located near the home point of block Y. lWhen block X is occupied and track loop w, w' is broken at contact 7c and loop TLO is broken at contact it, the engagement of shoe S with the ramp R" is ineffective to close the test or pickup circuit, and shunt s, s2 remains open, with the result that, when the continued upward movement of shoe S opens circuit breaker CB', the circuits A and C are interrupted by said circuit breaker interrupting tbe continuity of loop Z, Z', the brakes are applied, lan'ips L light up, and coil 8 attracts and holds armature 12 to hold circuit C open until such time as said circuits A and C can be restored by operating push button 7)?) to interrupt the circuit through coil 8 of relay DR, as hereinbefore explained.. After passing ramp R", the engineer operates said push button when the speed of thetrain has been automatically reduced, as described, thereby restoring circuits A and C. Upon reaching ramp R, the operations just described are repeated, and a second amilieation of the brakes and operation of the signal lights L effected, and the train is either automatically stopped, or may proceed, under properly reduced slpeed and absolute control, into the advance block X by the engineer again operating push button pb to break circuit B through the coil 8, thereby restoring circuits A and C to normally closed condition. Thus it will be seen that the functioning of the ramp controlled section is wholly independent of the insulated track, or electric controlled, section and, if the latter fails to operate., the train will be effectively protected by the ramp section of the dualistic system, and, conversely, if the ramp section fails, the insulated track section operates. Should both sections fail, the brakes are applied and the train is stopped at once.

The two ramp and connected loop arrange-- ment. as shown in Figs. l and 3, contemplates placing ramp R" the full braking distance back of the home signal point and is rendered effective by connecting `the two ramps by a single wire, properly insulated and protected, which wire constitutes a portion of the loop TL50. It will be Aevident, therefore, that the wayside installation of the ramp section is not only inexpensive to install and maintain, but reduces liability t-o derangement and damage of this portion of the apparatus to a minimum. Also, because of the fact that the engagement between the ramps and the shoe S carried by the locomotive, is only of sufficient duration to effect the initial closing of the test or pickup circuit by contact between the shoe and the ramp, and second, to raise the shoe to open circuit breaker CB', it is possible to employ relatively short ramps.

The alternate mode of obtaining remote control through the double ramp installation in each block or section is that illustrated in Fig. 4, in which each block or section of the track is subdivided into two sections by means of insulated rail joints j2, jg, the rails of the subsection adjacent ramp R" being represented by reference characters r2 and r3, respectively. In order to render this form of installation effective, it is necessary to interpose a so-called repeater circuit, which will respond to and repeat the operation of the track relay TR ,in the next section ahead. The repeater circuit includes a battery X', one terminal of which is connected by conductor NZ to finger 7c?) of the track relay TR, which finger normally engages a` stationary contact re, which in turn is connected with track loop section te to rail r'. The other terminal of the battery X' is connected to repeater relay LR, the other terminal of which relay is connected by conductor rc to rail r. So long as track relay TR is en ergized, the circuit through the repeater relay LR will be completed and the armature of said relay will be attracted. When the track relay TR is short circiiiited, the circuit of the repeater relay LR is broken at Contact rc and the armature of the latter relay falls away. The purpose of the repeater relay LR is to maintain the saine operating conditions in the subsection of the block adjacent the ramp R" as are maintained in the main section of the block, and also to maintain the integrity of the track circuit from the transformer T to the relay TR of the given block, such as X. To effect these results, the following connections' are em'- ployed; the joint in one rail is normally bridged by a loop comprising wire to, armature finger Z', contact y', and wire to, and siniilarly, point is bridged by wire se, armature finger Z, contact y, and wire scZ. These bridging loops are maintained intact so long repeater relay LR is energized. lhen, however, relay LR is deenergized by the short-circuiting of 'the track relay TR in the te, contact oc, linger Z, Wire ec, rai..

block ahead, it is also necessary to preserve Jthe continuity ot the track circuit in block il, which is effected by means of a conductor :te connected to rail r and having therein a suitable condenser f/ and ending' in a back contact Zic, engaged by finger J ot armature ci repeater relay LR, when the latter is deenergized; and a second conductor d', havinga condenser g" and contact bc cooperating with linger Z of the armature. Under the conditions linst indicated., the complete track circuit is follows: from one terminal or" transformer 'l` to rail i, Wire section r3, relay TR at the entrance ot block X, rail r2, Wire to, linger Contact c, Wire tol, rail r', to the other terminal of the transformer T. The condensers lo, g will prevent the passage ot direct current but will. allou7 the alternafting` current to pass freely to energize the trarlr relay TR, so long as block X is unoccupied. The Contact surface oli ramp l is connected to rail r as 'tollows: wire so, :linger Zo oi' arn'iature olf relay lil contact o, Wire so, to rail r2, so that, ivl'ien the shoe til oi` the locomotive engages ramp lt, the test or piclrfup vcircuit on the locomotive will be closed from the generator G (Fig. l), Wire 50, shoe E, ramp lil, Wire so, armature ringer Zo, contact fv, wire so, rail r3, to enfgine Wheels and trame, Around at G" to r agnet lll bar-lr to generator (i, the engine carried 'portions of the circuit being; the same as those hereinbeore described. .lt the advance block is occupied, relays and lill are deenergized, and the circuit last traced is brolren at contact o, ci relay LQ, consequently, when the shoe l engages the 'ramp lt, the test circuit will not be` closed and the circuits and C on the locomotire will be brolren at circuit breaker GB, thereby causing application cgt the brakes and the bright illumination oli the signal lamps ll. illhen the ramp is reached, the test or piclnup circuit is completed follows: generator wire 5l), shoe tl, ramp li, wire so connected to the contact sui-'tace ot the ramp, armature linger Zw. ot track relay 'llt of the block sliced, tact it, track loop section to, rail 9"', ci ne wheels and traine, to ground at G, magnet hl, baci( to generator, asbelfore. lt will be apparent, therefore, that the employment of the subdivision ot each bloclr adjacent the ramp at the approach point of the block and the interposition of the repeater relay circuit and the loop about the insulated joints between the track sections of each block Will in no Way interfere With the normal functioning ci' the insulated traclr section of the system, or with the normal operation of vthe track circuit, including the source of alternating' current T and the track relay TR in each block, but will, nevertheless, secure the certain and reliable operation of the ramp section ot the system either to clos the piclnup or test circuit, as each ramp is engaged, to give a. delinite indication when the block ahead is vloer, or, under danger conditions, to cause 'the circuits l and C to be interrupted when each ramp is passed, by the normal operation ot circuit breaker Uli, thereby causing;- application oit the brakes and the iiglitingr oit the signal lamps lo.

As an ancillary protective means to indicate the failure oli' e insulation ol" y the circuit wires, or the breakage o' the Wires, it is proposed to associate with all or any desired number ot the circuit Wires or conductors, detector loops, which, upon failure ol the insulrdion or disruption of any conductor, will short-circuit tbe particular current source supplying` said conductor. l? or example, in Fig. l the detector loop is associated with conductor 50 between the generator G and the shoe S, which conductor is subject to heavy vibrations and strains, said loop comprising a conductor wire .IZ Wrapped or Wound about insulated conductor 5l) and then brought baci; in a loop d pralleliug' aid conductor 5l? and lying adiacent to d, one end ot' Wire (Zi beingconnected to the negative terminal of the generator (l and the opposite end ot d beine; connected to one 'terminal of magnet E olf the test circuit. Any serious impairment of the insulation on conductor 5l?, or a breako'l the latter, `which would involve a contact with either wires d or ol, Will be evidenced immediately by the short-circuiting olf the generator (l between the conductor 50 and either one or both ot loop sections d, d. The saine protective eiiiect may be obtained with respect to the conductors supplied by current from battery 6, by connectingthe protective loop Wire one terminal ot battery (l and Windiug;v the Wire about the particular conductors to be guarded, as illustrated .in Fig. 5, in which Wire di? is con uected tothe negative pole oll battery (S and wound iu rons'aiilutions di; about conductor la in the holding circuit, thence continuing as loop il" paralleliugr Wire (7c, whence it is passed in successive windings or convolutions as di' about loop Vwires l and l, thence perallelini` conductor 23 in a section d and connected to one or more ol the metallic cups li/l o'j the truclr insulation, 'whence a linal section di is Wound. about conductor rElie failure olf insulation el any oit the Wires associated with the conductor loops will be evidenced at once by the short-circuiting o the battery 6 and the release ot the brano holding magnet, which would apply the brakes. llt will be understood, oi course, that similar protective loops be appLied to all ot the circuit Wires involved in the system but, as the Wires or conductors hereto'lore referred to are the principal ones which liable to damage or impair-nient,

under normal conditions of use, the protective loops have been indicated as applied only to such wires or conductors.

From the foregoing description, it will be apparent that the instant invention involves a simple and reliable dualistic system of train control, in which both elements of the system will be eil'cctive to accurately and reliably indicate safety conditions at all times, that will with equal reliability and effectiveness cooperate to indicate danger conditions and irst reduce the speed of the train and then automatically stop the same, under danger conditions7 unless the engineer assumes control after the desired reduction in `the speed has been made, each of the separate elements of the dualistic system being so far inde ndent of the other as to function perfect y in the case of failure of the other. In case both elements fail, the train Will be automatically stopped.

What I claim as new, and desire to secure by Letters Patent, is

1. The combination with a train carried electro-magnet governing means, of a normally closed circuit therefor, and a series of all-rail track circuits, a dual system of control and operation interposed between said track circuits and said electro-magnetic governing` means to act on said magnet governing means, one system operating according to an electrical mode of operation and the other according to an electro-mechanical mode of operation and both responding under the iniluence of a ygiven track circuit.

2. A plurality of all-rail track circuits arranged in immediate relation to each other, a normally closed circuit carried by a vehicle movable on the rails, including the rails and a track loop of negligibleresistance at a predetermined vpoint and directly controlled by the adjacent track circuit, a second closed circuit including vehicle control mechanism controlled by the first mentioned circuit, a normally open circuit carried in part by the vehicle and in part by the trackway and including the rails and the track loop aforesaid, and means carried by the vehicle for closing said open circuit at a predetermined point to first establish an alternative closed path for said second closed circuit and then to interrupt the original path of said second circuit under safety conditions.

3. A. plurality of all-rail track circuits arranged in immediate relation to each other, a normally closed circuit carried by a vehicle movable on the rails, including the rails and a track loop of negligible resistance at a predetermined point and directly controlled by the adjacent track circuit, a second closed circuit including vehicle control mechanism controlled 'by the first mentioned circuit, a normally open circuit carried in part by the vehicle and in part by the trackway and including the rails and the track loop aforesaid, a mechanical circuit ybreaker in said second circuit, and means carried by the vehicle for closing said open circuit at a predetermined point to close a shunt around said circuit breaker to maintain the integrity of said second circuit and then to operate said circuit breaker to interrupt the original path of said second circuit under safety conditions.

4. The combination with a vehicle carried. normally closed circuit, and an electro-magnet governing means included therein, of a normally closedtrack connected control circuit operatively associated with the rst mentioned circuit, an all-rail track circuit, a point of resistance on the track that is presented to and withdrawn from the control circuit, under the influence of the track circuit, track engaging mechanically operated means for breaking the iirst mentioned circuit, and a normally open vehicle carried circuit associated in controlling relationship with the first mentioned circuit and controlled by the ,track circuit under safety conditions to close the first mentioned circuit against the mechanically operated means.

5. The combination with a vehicle carried normally closed circuit, and an electro-magnet governing means included therein, of a normally closed track connected control circuit operatively associated With the first mentioned circuit, an all-rail track circuit, a point of resistance on the track that ispresented to and withdrawn from. the control circuit under the influence of the track circuit, track engaging mechanically operated means for breaking the iirst mentioned circuit, a normally open holding circuit, and a normally open control circuit co-operatively associated with the first mentioned circuit and controlled by the track circuit under safety conditions to close the first mentioned circuit against the action of the mechanically operated means.

6. The combination with a vehicle carried normally closed circuit, and an electro-magnet governing means included therein, of multiple control means operatively i associated therewith, ,embracing a normally closed control circuit, a normally open controlling circuit and a mechanically operated means interposed between the iiirst mentioned circuit and the track, an all-rail track circuit, controlling devices at traffic control points governed bythe condition of the track circuit for opening said normally closed circuit through one of said controlling devices and separately opening the same through the action of the mechanically operated means under danger conditions both of said controlling circuits coi-operating under safety conditions to maintain the first mentioned circuit closed under the influence of the track circuit against 4the action of the mechanically operated means.

7. An automatic train control system of a dualistic character having in combination with a normally closed circuit an included electro-magnet carried on a vehicle, of mechanically operated means for opening said circuit, embracing members along the track and a member carried by the vehicle disposed in running position to engage said track members, an all-rail track circuit, ve-

hicle carried control circuits interposed between the first mentioned circuit and the track circuit and controlled by the latter at predetermined points one of said control circuits under safety conditions holding closed the lirstmentioned circuit while the other under like conditions automatically places a compensating shunt on that portion of the rst mentioned circuit about to be broken by the mechanically operated means.

8. ln a dualistic train control system, a vehicle carried working circuit and a cooperatively associated control circuit both of which are responsive to a cessation of current said control circuit having two sets of normally closed terminals arranged in series, one of said sets being vehicle carried while the other is arranged in operative relation to the track, means depending upon the movement of said vehicle to open said terminals under danger conditions at prede-- termined points, a loop of negligible resistance for bridging each of said terminals under safety conditions to form a compensating pathway, a vehicle carried transient circuit for controlling the loop for bridging the vehicle carried terminals, an all-rail track circuit for controlling the transient circuit and the other loop to render inoperative the working circuit under safety conditions.

9. In a dualistic train control system, a vehicle carried working circuit and a co-operatively associated control circuit both being responsive to a cessation of current said control circuit having two sets of normally closed terminals arranged in series in the control circuit one of which is on the track and the other on the vehicle, means depending upon the movement of said vehicle to open the terminals of both under danger conditions at predetermined points, an allrail track circuit, and partial circuit devices controlled by the track circuit for providing a compensating pathway for the respectiver sets of terminals under safety conditions to render the working and control circuits unaected under safety conditions, aty

such points.

l0. ln a dualistic train control system, a vehicle carried working circuit and a cooperatively associated control circuit, both being responsive to a cessation of current, said control circuit having included at three different points circuit making-and--breaking devices two of which are vehicle carried while the other is arranged in direct operative relation to the track, one vehicle carried maaier circuit n aking-and-breaking device and that in operative relation to the track being opened by the movement of the vehicle past a given point in the track under danger conditions, an incomplete ti ansient control circuit eitending substantially in parallel relation with the first mentioned control circuit and that is responsive to closure to cause the closure of the other vehicle carried makingand-breaking device, and an ail-rail track circuit vfor controlling the closure of the transient circuit and the breil 'ng-and-making device arranged in operative relation to the track nder safety conditions.

il. ln a dualistic train control system, a vehicle carried working circuit and a co-operatively associated control circuit both being` responsive to a cessation of currentsaid control circuit having two sets normall y closed terminals arranged in series one of which is vehicle carried while the otl er is arranged in operative relation to the track, means depending upon the movement of the vehicle to open said terminals at predetermined points, a transient co-ordinate control circuit responsive to closure thereof to insert a low resistance shunt across the gap of the vehicle carried terminals, a track loop for closing the transient control circuit and the track connected terminals of the first mentioned control circuit, and an all-rail track circ iit for controlling said track loop, the whole arranged to render the `first mentioned control. circuit and the working circuit inperative unoer safety conditions.

12. ln a dual system of train control, a cab carried working circuit and a co-operatively associated control circuit that is track connected, both of said circuits .having a common source of electric energy and working on the closed circuit princinle, and anotl er control circuit co-operating with said working circuit that is fed by a diiferent source of electric energy and possesses a different character of operation, a mechanically operated means for breaking said working circuit and a fixed member on the track for actuating said mechanically operated means, and an all-rail track circuit for simultaneously controlling said control circuits to lhold the working circuit closed against the action of the mechanically operated means under safety conditions.

13. lin a dualistic train control sv, i plurality of all rail track circuits, each including an insulated track section, a source of current and a relay; a control circuit carried by the vehicle; partial circuit devices co-operatively associated with the track and directly controlled by said relay to determine the condition of said control circuit; a second circuit on the vehicle normally maintained closed by said control circuit; and train control mechanism rendered operative upon cessation of current in any of said cirloo lli

cuits, in combination with a normally incomplete transient control circuit, partial circuit devices therefor co-operatively associated with the track circuit and directly controlled by the track relay to determine the condition of the first mentioned control circuit and the second circuit.

14. In a dualistic train control system, an insulated track section, a source of electric energy and a relay: a control circuit carried by a vehicle; partial circuit elements for opening and closing said circuit that are directly controlled by said relay; a second circuit on the vehicle normally maintained closed by said control circuit; and train control mechanism made operative upon ccssation of current in any of said circuits, in combination with a mechanical circuit makerand-breaker that engages a part on the track at predetermined points for the opening of the second circuit every time the said breaker engages a part on the track, a normally incomplete transient control circuit carried on the vehicle, a partial circuit therefor cooperatively associated with the track relay to determine the condition of said circuit, and means controlled by said transient control circuit for inserting a compensating shunt across the break about to be effected in the second circuit by the circuit breaker under safety conditions, and a third signal and holding circuit that is initially closed under the influence of the transient control circuit and the track relay for maintaining said compensatingk shunt in closed position.

15. A railway cab signal and cqntrol system, comprising a signal and brake controlling circuit, a source of electric energy therefor, `an all-rail track circuit, and means comprising two independently operating circuits interposed between said track circuit and the first mentioned circuit that are controlled by the track circuit to maintain the integrity of the first mentioned circuit under safety conditions at traffic control points, anda mechanically operated means and a point of resistance operating respectively to effect an opening of the first mentioned circuit under danger conditions.

16. In a dualistic train control system, an insulated track section, a source of current and a relay, another source of current and a control circuit carried by the vehicle, partial circuit elements Ico-opcratively associated with the track section and directlv controlled by said relay to determine the condition of said control circuit; a second circuit on the vehicle normally closed through the control circuit; train control mechanism rendered operative upon the cessation of current in any of said circuits, in combination with a mechanical circuit maker-and-breaker, a fixed member along the track for engaging and operating the latter during the movement of the vehicle to open the second circuit every time it passes said point, a second source of current on the vehicle, a vehicle carried partial circuit co-operatively associated with the relay to complete said circuit with the inclusion of the second source of current under safety conditions said partial circuit being responsive under closure to effect a shunt around the point in the second circuit subject to the mechanical breakage before it is effected, and a holding and signal circuit in parallel with the first two mentioned circuits that is fed by the first mentioned source of current which is established by the partial circuit under safety condition through the infiuence of the track relay.

17. In a dualistic train control system, a normally closed working circuit, a signal and train control mechanism rendered operative upon cessation of current in said working circuit, a normally closed control circuit for determining the condition of said working circuit, a mechanical make-and-break device for breaking and making the working and control circuits, a fixed member along the track for operating the device to break the working and control circuits every time the fixed member is encountered, a normally open control circuit responsive to closure to effect a compensating shunt across the break effected by the mechanical circuit breaker to preserve the integrity of the Working circuit, .a signal and holding circuit that is closed upon the closure of the open control circuit to retain the compensating shunt when established, an al1-rail track circuit having a source of electric energy and a relay, and partial circuit devices co-operatively associated with the track circuit for determining the condition of the normally closed and normally open control circuits respectively.

18. The safety system for railway trains hereinbefore described, comprising two train carried co-ordinate circuit members, a track circuit from which they are disconnected under danger conditions and to which they are connected under safety conditions at predetermined points, a normally closed( brake control circuit carried by the train controlled respectively by said co-ordinate circuit members, a mechanically operated means interposed between said brake control and track circuits that acts to mechanically break said control circuit when said co-ordinate circuit members are disconnected from the track circuit under danger conditions and means associated with one of said co-ordinate circuit members to maintain the other coordinate circuit member closed against theaction of the mechanically operated means under safety conditions.

In testimony whereof I aix my signature.

JOSEPH WHITMAN BUELL.