US1791780A - Train-control system - Google Patents

Description

7 Sheets-Sheet 1 Feb. 10, 1931. A. G. WILLIAMSON TRAIN CONTROL SYSTEM Original Fil-ed March 5, 1927 Swuemtoz m fmzm Feb. 10, 1931. A, G. WILLIAMSON 1,791,789

TRAIN CONTROL SYSTEM Original Filed March 3, 1927 7 Sheets-Sheet 2 Feb. 10, 1931. A. G. WILLIAMSON TRAIN CONTROL SYSTEM Original Filed March 3, 1927 7 Sheets-Sheet 3 A q Q a g M W QKJ M u new \km LEU may SW a L Q g @N Q m A w n m g QN m T avwemto'c Feb. 10, 1931. A, G. WILLIAMSON TRAIN CONTROL SYSTEM Original Filed March 3, 1927 7 Sheets-Sheet 4 Z'II Feb. 10, 1931. A. G. WILLIAMSON TRAIN CONTROL SYSTEM 7 Sheets-Sheet 5 Original Filed March 3, 1927 vwentoz m $51 A (l-Horne Feb. 10, 1931. A. e. WILLIAMSON I 5 TRAIN CONTROL SYSTEM- Original Filed March 5, 1927 7 Sheets-Sheet 6 Ell 351 flbtemug %%cP/=A Feb. 10, 1931. G. WILLIAMSON I 1,791,780

I TRAIN CONTROL SYSTEM Original Filed March 3, 1927 7 Sheets-Sheet '7 i A N ambgutoz $3M A4 flue Mung Patented Feb. 10, 1931 1 UNITED ,sTArEs PATENT QQ H 1 AIRBAG. WILLIAMSON, or CARNEGIE, PL NNsYLvANIA, AssrGNon', isY MEsNEAssIGm MENTS, TO THE UNION, environ? &, SIG AL COMPANY, or

p TRAIN-CONTROL SY Application filed March 3; 1927, Serial No 172,325.. Renewed November 19,1929. 1'

This inventionrelates-generally to train control and track Way circuit systems, and has for its main object and feature the pro-- vision of simple means whereby at leastthree indications may be transmitted from trackway elements, preferably thetraffic rails, fed by a powersource Suppl ing a singlefrequency current. I V

In the accompanying drawings the invention'is shown in "severalconcrete and preferred forms in which:

Fig. 1 is a diagrammatic view of a track circuit embodying one form of the invention.

Fig. .2 is a diagrammatic view of-one form of the train carried apparatus, showing the use of rectifying detectors.

Fig. 3 is a view similar to Fig. 2 showing the use ofamplifiers. .j Fig. 4 is a diagrammatic View showing a second form of track'apparatus. Fig. 5 is a 'diagrammaticview showing a modifiedform of the invention 'ofFigs. 1 and 4. :1 r r Fig. 6 is.- a diagrammatic view showing a still further modified" form of the invention in which two track circuits are employed.-

Fig. 7 shows a diagrammatic view of both train and track equipment of a modified form of the invention. 1

Figs-8 and 9 are diagrammatic views show-. ing the, difierent pronounced harmonic components of a non-sinusoidal alternating cur-' rent. p a Fig. 10 is a diagrammatic view of a magnetiz ation curve showing a the saturation point. V

Fig. 11 1s a diagrammatic view showing a modification of the construction disclosed in frequencyalternating current can be made non-sinusoidal; that is: the-alternating curswrss'v-ALn rENNsy q VANI A conrona'rronor PENNSYLVANIA V l rent can be so modifiedfthat. the momentary values of a compound resultant wave do not vary in accordance with a pure sine law, but. 1,

has momentary valueswhich are. the summa tion of the sine functions 'of the waves of several components. The sine function possessing the lowest frequency is 'calledthefirst harmonic component'or the fundamentahand all the other sine functions, whose frequencies are multiplesof that of. the fundamental, are

called-higher or upper harmonic components. This is illustrated in the diagram, "Fig; 8 which shows one. cycle of asingler-frequency alternating current-wave in 'whiclr'the horizontal axis represents time and the vertical is the summation of the amplitudes of the several harmonic components.

The harmonic components shown in Fig. 8 ar'ethe'first, or

fundamental, the third and the seventh, and it will be understood that one or more such pronounced harmonic components may be utilized, by properly tuning pick-up circuits on the train, to give various indications. on the train to control suitable indicating means such as signals. or brake'setting means or both. a Y j A track way arrangement embodying the invention in one form is-shown in Fig. 1 in which the track elements are traffic rails 1 and 2 over which traflic moves in the direction of'the arrow, said rails being preferably arranged in blocks A, B and G by means of insulated joints 3 orotherwise. Referring particularly to block 13, a power source to supply a single frequency current is shown and this may begenerator G which, in that event, could be connected directly by suitable leads to " rails 1 and 2 of each block, but, preferably, generator .G supplies powerto line wires 12 and 13 and they in turn deliver current to the railsby means of transformer V T?) which supply the rails directly. The point that we are making is that either generator G or transformer T6 may be considered the power source. Transformer Tb is here of the type having a closed ironcore so that by proper designing of the iron magnetic path the working point of the magnetization curve will be at the 'point X, Fig. 10, in consequence of which secondary 4 becomes a source of alternating voltage supplying alternating current of non-sinusoidal form and having pronounced harmonic com- 7 pon'ents. A probable explanation of this phenomenon is that there is a lack of uniforniity of the magnetic field of the iron con stituting the magnetic path of generators and transformers, and this is illustrated in Fig. 10 which showsga typ cal magnetization curve for iron. Let us suppose that the magnetiza tion ofthe iron has been brought topoint X. If now, by means of anadditional alternating magnetization force, equal increments and decrements be added, tlie'inagnetization will increase duringt'ne positive half of the cycle bythe small amount ef, while, during the negativehalf of the cycle magnetic induction will decrease by a considerably larger amount 00+(Z. Such an asymmetrical condition gives rise to pronounced higher harmonic components, the third harmonic component being particularly prominent.

Referring to Fig. 1, one'side of secondary l 18 connected to raill by wire 5, and rail 2 is connected to the o'pposite terminal of sec- 7 .end of block B in Fig. 1;tr ack relay Rb is con nected to the rails by wires 16"and 17/ It will now be seen that normally, current flows from secondary 4- along, let ussay, WllG 5,

rail 1, wire 16, coil of relay Rb, wire 17, rail 2, wire 6, ohmic resistance 7, wire '8, front contact 9'and wire 10 and back to secondary 4. If relay Ra is deenergized the return from rail 2 willbe over wire 6, impedance coil 11,

back contact 15, wire 10 and secondary 4.. The track relay, such as Rb, is an alternating current relay of the type that does not depend for its operation upon any particular'wave form of alternating current and will therefore function in the same way whether-ohmic resistance"? or impedance coil 11 is in the circuit; provided, of course that the values of 7 and 11 are such thatthe mean effective value of the current flowing in Rb is the same with either 7 orll in circuit.

The efliect,upon the current flowing in the rails, by cutting? and 11 in and out is as follows: When ohinicresistance'7 is in circuit, and the load on secondary 4 is largely noninductive, then current flowing in the rails willhave' a pronounced third harmonic component in additionto a pronounced first har 'monic component (or fundamental) that is,

ponent thereby leaving but a singlepronounced harmonic component, in this instance the'funda-mental, and the wave curve will then be substantially as shown in Fig. 9.

The probable explanation of this phenomenon isas follows: There-is both a voltage curve and a current curve and if the circuit contains only ohmic resistance the current curve will havesubstantially the same shape as the voltage curve. On the other hand, if the circuit contains largely inductive, resistance the current curve will approximate more closely-apure sine wave than .will the voltage curve, this being due to the fact that inductive reactance is proportional tofre quency and thus greater in value for the higher harmonic components and it therefore tends to suppress 'the'higher harmonic components of the resultant wave morefthan it tends to suppress the fundamental or first harmonic component. Again, should the circuit contain capacity, then the higher harmonic components may be more prominent in the current curve than in the voltage curve. It will therefore be understood. that resistance element 7 isnot anecessary part of the invention. It is placed in thedrawing largely to illustrate thecharacter ofthe-circuit. it does, however, possess areal function in preventing the current from being dissipated when impedance coil 11 is not in circuit".

In th'e illus trative form of the invention described thus far it will be understood that allthe blocks of the system are equipped in the manner described in connection with block The track way arrangement, in the present form, is therefore that when block A is unoccupied.aiid'relay Ra is'energized a non-sinusoidal single-frequency alternating current will fiow in the rails of-block B and this current will be characterized by two pronounced harmonic components, here the first and-the third components.- Vlien block A is occupied and relay R0; is deenergized then the current in the rails of block B will have a single pronounced harmonic component, here the fundamental, and a very small, if any, third hamonic component. If a second train enters a block already occupied then such second train will receive no current, due to the shunting action of the wheels and axles of the trainin advance.- e thus establish three traffic cond-itions with a single alternating current, a great simplification over systems now used. The track way arrangement shown has another advantage in that it is not necessary to have a separate trackcircuit to energize the track relay, this function being performed-by the same cur:

rent as that which energizes the means on the train. It will also be understood that, wayside signals of the three position type can be operated and controlled by a track way circuit of this type by having two track relays, one responsive to one pronounced liar-a voltage'induced' in them by current Iiowingv in opposite directions in the trafiic rails will be additive, and are further connected in a circuit including wires 22, 23, 25 and 2,. as well as primaries 24 and 26 of transformers T and'T. Said transformers are alike and are of the type commonly used in this class of work, their primary windings having, a

high impedance. E and E represent two rectifying detectors of the electron tube type containing here three elements, a filament,

a grid and aplate. The grid circuit of tube V E is as follows: secondary 28 of transformer T, wire 29, condenser 18, wire 19, grid 32, filament 33, :wire .34 and back to secondary 28. Tuning condenser 35 bridges this circuit by means of wires 36 and 37, and, in this instance, condenser 35 is so chosen that the cir cuit is tunedto resonance with the fundamental or first pronounced harmonic component of thetiackcircuit current. Thegrid circuit oftube E is as follows: seconaryr38 of transformer- T, wire 39, condenser 40, wire 41, grid 42, filament 43, wire 44 and back to secondary 38. Tuning condenser 45 bridges the circuit by means'of wires 46 and 47, and, in this instance, condenser 45 is so chosen that the circuit ist-unedto resonance withthe third pronounced harmonic component of the track circuit current.

Generator G, of the train equipment, is driven by any suitable means, such as a steam turbine, not shown, and delivers a voltage that drives motor M of motor generator MG. Thegenerator end of the motor generator is supplied with two commutators G and G the former furnishing a voltage suitable for the filament circuit of E andE, and the latter a'voltage suitable for the plate circuits of tubes E and E. The filament cir- 52, plate 1530f tube E, filament 33 andwires 50. and 54 back to commutator G 1 The plate circuit of tube E consists of: commutator G wires 51'and 55, coil OfreIayR, wire 56, plate 57 of tube E, filament 43, wires 44, 49 and 34,-filament 33 of t-ubeE, and wires 50 and 54 back to'G By the foregoing means the grid circuit of tube E is responsive to the influence of another pronounced harmonic component of the track way current.

The effect of each of these pronounced harmonic components is to render the grid, complementary thereto, negativefwith respect to the filment so long as the appropriatecurrent flows in the track way. If the original value grid circuit of tube E isresponsiveto thQzlIlfiLlBIlCBOfOIlG pronounced harmonic component and the of the plate circuit current is assumed to be 1.00 when no curr-entis flowing in tliegi id' circuit, then, whentlie grid-is rendered negative by the induced voltage in the grid'circ'uit, the plate circuit current is choked downto'say 0.40 after the manner describedin detail in application Ser. No.147,403, filedNovember 10,1926; that is, anintermediate value of plate circuit current is established so long as the appropriate 7 current flow is present in the ralls. 2

Relays R and 'R arealike'landare lier'e of the direct current polarized type. Each 7 relay is provided with a single polarized'armature which is so biased by air gap adjust-;

merits and strengthof magnetic poles that i it will take one position "(right hand posiflowing in the coils of the relay, butyif the current value of the plate circuit is either increased or decreased or fails totally, then the polarizedarinature will be forced to anothe)r position'(in Fig. 2the left'hand positlOIl I 1 i l The indicating. means used may be of any suitable character and may be merely an indicator such as I having three difi'erentlycolored lights and these lights receive, in this instance, power direct from generator G"; The proceed indication light-circuit is as follows: generator G, wires 58 and 59, armature 30 of relay R, contact point 31, connection 60, armature 66 of relay R, contact point 61, wire 62, li 'ht 63 and wires 64 and 65 back to generator G. The caution light circuit is as follows: generator G, wires 58 and 59, armature 30, contact point 31, connection60,

armature 66, contact point 67, wire 68, light 72, 64 and 65 back to genera:

-1o0 tion 2) when current of the proper 5 I polarity and of a givenvalue (here"0.40) is 1 unoccupied, thenthe wheels and axles of the train will shunt the" current from track rielay Rb, and, the track cir'cuit'current for block B there'being only ohmic resistance in said circuit (graphically indicated by element 7 will have two pronounced harmonic components, and this current will be picked .up by coils and 21. Each of the grid circuits oftubes E and E will respond to its proper pronounced harmonic component and the grids of both tubes will be rendered negative with the result that the plate circuit current of each tube will bechoked down to an intermediate value of say 0.40 and'consequently armatures and 66 will both occupy the righthand' position shown in Fig. 2. This will close the proceed indication circuitpreviously described. It block A were occupied when the train entered block B then track relay Ra would be deenergized and the current supplied to the track rails would pass through impedance coil 11' and this would eliminate, or at least greatly minimize or render ineifective, the third pronounced harmonic component and therefore the grid of tube E would no longer remain negative. Consequently the value of the current in the plate circuit would rise to 1.00, armature 66 would move totheleft hand position and the circuits would rise to 1.00 and both arma tures 30 and 66 would be moved to the left hand positions with the resultthat the circuit previously described through danger light 71 would be established. It will also be understood that should a wire break in either of the plate circuits or the source of power fail then either or-bot-h armatures 30 and 66 would move to the left hand position.

The train-carried apparatus can of course be made as elaborate as desired and may in clude bothbrake setting means and multiple speed control means in accordance with the requirements of the system on which it is used. In Fig. 2 there happens to be shown, in addition to indicator 1, brake setting means designated by three magnet valves M, M

. and M, the coils of which are connected'in parallel respectively with the proceed, caution and danger indicationlights. The circuit tor valve M branches off wire 62, and then passes over wire 73, coil of M, and wire 74 back to wire 65. The circuit for valve M branches ofi wire 68 and then passes over wire 75, coil of M and by wire 7 6 back to wire 65. The circuit for M branches oil wire and then passes over wire77, coil of M", Wire 78 and back to Wire 65. In Fig. 12'is shown a detail view of the valve structure, which, however, may be varied widely. BV indicates a brake valve which in its normal position has port 131 closed and port 125 open. Under these circumstances, pressure can flow from. the brake pipe to the engineers valve but cannot flow to exhaust port131'. The

brake valve ismaintained in this position by pressure under piston 130 but when this pressi'u'efa ls port 1251s'closed and port 131'is opened thereby connecting the brake'pipe with exhaust port 131- Pressure is main-v tained under piston 130 by the three magnet valves M, M and h the valve ports of which i are connected-in series with each other, and are connected at one end with the cylinder containing piston 180 and at the other end with an :ghaust 131". WVhen valve M is energized port 126 isclosed'and valve 124 '131" and ports 131 and 131 will be open and port 125 will be closed, thereby applying the brakes. Each ofthe magnet valves is so constructed that when it becomes deenergized its armature such as 1 23, 128 or 128 falls so far down that it will not be: lifted when the magnet is reenergized. The engineer should therefore acknowledge each indication by lifting a plunger such as 122, 129 or 129 manually to thereby restore the armature;

. In Fig. 3 is showna second embodiment of the invention in which electron tubes E and E: are used as amplifiers and relay's R and R are alternating current relays. In this formot the invention two pairs of pickup coils are used, 80 and 81 being-connected to the grid-filament circuit of tube E and coils 83 and 8 1 being connected to the grid filament circuit of tube E. Condensers 82 and 85 span the respective grid-filament circuits to tune the two circuits to resonance of the two pronounced harmonic components. In this instance the grids of the tubes are not rendered negative but an alternating component is impressed upon each plate circuit and eachrelay R and R responds to the influence of the proper pronouncedharmonic component in the track circuit. The track circuit shown in Fig. 1 can be used-in connection with this train equipment, and the general method of operation will be the same as that previously described in connection with Figs. l and 2.

In Fig. 4 is shown a modified form'of track circuit construction in which, when the track relay of the block in advance is energized, a shunt path 1s;closedgaroundimpedance coil 3 8t and which shunt path includes the con;-

I ing'thepositivelhali of the cycle ofithe alterdenser 87. This condenser is given such value that it counteracts {the inductivereaetance of coil '86 so, that the apparent rcsistance otter-ed to the track circuit current is thatof ohmic resistance. Under these conditionsth'e track current will have two pronounced l arnioniccomponents, the first and the third. lVhenthe track relay ofjthe block injadvance is'deenergized then impedance coil 8(lis placed 7 in circuit and the third harmonic component ofthe track current will be suppressed; The construction shown in F1g. 4: can be associated with the construction shown in either Fig. 2 or 3. w

nating current the induction' will increase but slightly while during the negative halfof the cycle the decrease will 1 be relatively large.

7 This uneven change in the induction otthe iron core willproduce a Wave form in the current of the secondary l of transformer Tb which will have a pronounced third harmonic component as well as a pronounced first-harmonic component. .lVhen'relay-R is deenergized and coil 250 thereby also becomes de'energized then the working .point on the magnetization curve is well down belowthe knee otthe curve and the pronounced third harmonic componentis suppressed. The result is thereforethe same as inlFigs. '1. and .4.

In Fig. G is shown stillanother modification of the invention in whichtwoztrack circuits are; used As there shown, secondary 4 of transformer T?) is connected, at the outgoing end oftheblock, to'rails 1 and 2 to which latter, at the incoming end of the bloclgis connecteclthe usual track relay, therails being in series; Inasmuch as this circuit contains merely ohmic resistance the'currentflow in the rails willhave, let us' say, a pronounced third harmonic component. 200 indicates another secondary oftransfo'rmer Tb which supplies power to a circuit asfollowsz wire 201, contact 202, armature 203 of the'track re lay of the block in advance, Wire 1204, center tap205,rra'ils1 and 2 in parallel, centertap' 206 wire207 and backt o secondary 200.7 51nasniuch asfthea resistance of thisj-rcircuit is" V 1 largely; noneinductive} the Lcurrent". flowing therein; will :h'avef. pronounced. higher ,moniecomponents Sletfusi say" notably; the

' fthirdzharmonic component; Pick-up: coils 2l0and211 for train 212iareso-conne'cted that difi'erent 'tiiaiiic the voltage induced in them by the current supplied by'secondary 4 to the rails in series will be additive, and the pick-up circuit is tuned to resonance at the frequency of the third; harmonic component. This pick-up circuit is connected to the grid circuit of tube 2) inthelsame manner'as'in thatfig- '2 in, the way previously described." I: Pick-up coils 213 and 21 loftrain-2l2 are so connected that voltage induced-therein byv current fiow ingin' parallel in-the rails will be additive, and the pick-11p circuit is tuned to resonance at the frequency of the third harmonic comcs0 .ureand wilitheretore control relay R. of Fig.) 7 i relay "of the block in advance is deenergized advantage of, this particular form of the inyention, in which hothpick-up circuits are responslve to higher harmonic components is that this system is not subjecttothe influence of stray currents. z. H

The, systemisnot' limited to three indications; Obviously two indications, or even one indication can be used as will be apparentirom'Fig. 6; So also a number of indications'greater than three can be employed, since this may be desirablewhen short blocks are. used andthe-speed of certain'i'classesof trains'ishigh, 7 T

i In Fig. 'Z a system having lmore-than three indications is shown; When four indications aredesired-an'additional tubeE is employedvand also an additional coordinating relay- R with the necessary grid, plate and filament circuits; However, ea s this additional.;eqi iipmentiis largely a repetition, of

what has been descrihed in connection ith i tubes "E and'ET it-is thought, to be unneces-J 'saryatoi repeat the description thereof; In

Fig.7 we have chosen to use the tubes as recernor geared 't o-the train. Four'segments arev employed j227, 228, 229 Land 230 with fjwhic'h"thecontact arme-ngagesand thesep seg'- V nientslareaof dilierentflengths tothe-reby in itson the train under posegdilierentspeedli ,onsi-n a manner I well 'tifying 'detectorsgbutxit will be un'derstood from Fig. 3 that thetubes 1may be used as amplifiers. In-Fig. -7 the indicating means understood. The track circuit arrangement shown in Fig. 7 is a modification of that shown in Fig. 6 in that a line relay 215 is employed at each block together wit-ha controlling circuit for this relay 215. Associated I With transformer Tb is a secondary 21 6 con' nected in a circult as follows: w1re'2l7, ar-

mature 218 of the track relay of block A, contact point 219, wire 220, coil of relay 2150f block B and then by a common return wire indicated at back to secondary 216.- That track circuit of block C which includes the two rails in parallel is then controlled through a contact of line relay'215 in such a way that when relay 215 is'energized then the parallel track circuit passes throughnon-inductive resistance 221 and front contact 222, whereas when relay 215 is d'eener'gized then said parallel circuit includes inductive react ance'22l-and-back contact 223 f Therefore each block'is provided with a series-rail circuit current having a plurality of pro- 40 c r train entersthe block C, then the second train nounced harmonic components, here the first and third, and with a parallel-rail circuit current also having a plurality of pronounced harmonicicomponents, here the first and third, and it will be understood that this is will receivef no'current at all. -The'pickuip coils on thetrain associated with tubeE are 'connected to respond to the seriesfrail cur rent, and the pick-up circuit associated therewith is tuned to proper resonance atthe frequency of'one of the harmonic components of this current-preferably the I higher .h-armonic component. =The'other pair of'coils in the train is connected to responda'to the parallel-rail current and the grid circuitof tube E' is tuned to resonance; at the frequ'ency of the first harmonic component while-the grid circuitoftube E is tuned to resonance withthe third' harmonic component of said parallel-rail circuit current;- Therefore, when a train enters a block, andthe-neXt two blocks in advance are unoccupied all: three tubes E, E and' E; are influenced and relays R, -R" andqRT will hold;theirfarmaturesein the rig-lit hand positions and; themaximum 1 speedwilhbe permittedQ Ifthe second 'block in advance is occupied andithe' first block in advance is unoccupied then tubes E" and E;

are-"influenced a'n'd 'relays Rfiand Rf will; holtl their armatures in the right hand positions, but tube IE will not be influenced and relay R" will hold its armature inthe left hand position thus permitting the train to proceed at the second speed. If the first block in advance is occupied then tube E only is influenced and only relay R will hold its armature in the right hand position, the armatures of relays R and R being in the left hand positions, thus permitting the train to proceed at a still lower speed. Ifthe block is already occupied when the second train enters then.

all three relays R, R and R will move their armatures to the'left hand positions and the train can proceed only .at the lowest speed.

In Fig.11 shown a modification of the form of the invention shown in Fig. 7.. Here each block is provided with a two-element A. C. polarized relay such as Ra so constructed that when ablock is supplied with current of one relative polarity from a secondary such as ethe corresponding track relay will hold armatures 252, 253 and 254 in the right hand positions, will hold said armaturesinthe left hand positions if'current of reverse relative polarityisapplied,arid when a track relay is deene'rgized the correspondingarmatures will occupy-the mid-positions; Each track transformer, of which Tb is an example, is

provided with a se'condary 255 that supplies.

power to the local element'of the correspond mg track relayyand associated with each transformer is a coil 250 to increase the "magnetization of the iron core of the transformer to near the saturation point so that, whenever coil250 is energized by battery 251, the current delivere d'by secondary 4' will have .pronounced higher'harmonic components. The circuitfor 'coil250 and battery 251 passes through the rightand left hand contacts of the track'relay Ra, and said coil 250-will thereforebe energized whenever thetrack winding of a relay, as Ra, is energizedfregardless of the relative polarity of the energizing current. Each'block; is provided with two filters 256 and 2.57, filter25i6jbeing composed 'ofi nductance 2'58 and capacity 259 arranged in parallel, and the. values; of. those elements are so chosen thatthe filter is resonant to the seventh harn onic'component; ofcurrent sup.-

p'lied bysecondary 1 and will'readily pass; it while the other harmonic components; except the first, will" be suppressed. Filter- 257 is composed ofinduotance 260 and capacity-261 in parallel and their values are so ohosenthat it is-zre'sonantv to the" third harmonic? com".- ponent of current delivcred byfsecoiidary' 4 and wiill i readily pass; it- While theother liar..- monic- ;components, except the first, will be its suppressed: t When, therefore,, ther armatures, 0f: r iayna occupy the? right-hand. positions 1a current will; flow infthe" rails having} two pronounced harmonic components, here the l first "and seventh; and when; said? armatures occupy the left hand positions acurrent will flow in the rails having two pronounced haremonic components, here the firstand third. hen the armatures occupy the mid-positions the current in the-rails ill have only the first harmonic component. 'Tll6S'3,Yl3l11.6

conditioifis correspond to-three ditl'erenttralifit: conditions, thefourth being totalabs'enceof current 'WlllCh condition prevailswhen 'a a I block 13 already occupied by a train when the second train enters. *On the train, the grid circuit of tube E is tuned to the first harmonic COlHp0l16I1t,' l l1 grid circuit of-tube SE. is tuned to the third harmonic component and the grid circuit of tube E istuned to the seventh harmonic component. Relays R, R and-R are each providedwith twopolarized armatur'es in place o'f one showniinother forms of the inventioi'l. l Vhen tubes E and E are influenced andtubc 'E is uninfiuenced, (two blocks in advanceunoccupied) then thefmaxim uin speed is permitted; with tubesE and E influenced and tube E" uns influenced (second block in advance oc cupied) 'then the second speed is permitted;

- flow, means in said connectionstor' establisha given pronounced harmonic componentsand. othermeans 1n said connections 'to determine way elements,'a current now, means in said ing ware -form, for saidjcurrent, -having if said given harmonic components 7 are; re-

tained in thewaye form ctthe-current'flowing in thetrackwayelements or it; saidgiven harmoniccomponents are suppressed.

A' trackwa-y ci'rcu'it syst'em including-t 'trackway elements divided into blocks, a

power source to supply n elements ofa block to establisln in' said track- 'connections to establish awave form for said current hav ng given pronounced harmonic components, othermeans lllSLlCl connections to d termine itsaidgiyen' harmonic components are retained in the -wa-ve formofthe' currentflowing in the'trackway elements of a. block, Orif saidg ven harmonic components are supe pressed, :and a tra 'trol' the connections aforesaid." 1

,sin'gle alternating {current-of a"g1ve11 frequency, con-nectlons between said power source and the trackway slatin'g device {responsive I A tracliwaycircuit system; ncluding'ti trackway' elementsa powensource' tosupply a singleialternating current of a given fre: quency, said current having a pluralityof pronounced components, and traflic controlled Variable connectionsbetween the source and the tra'ckway elementsito selectively re tain or suppress one-or. moreof; said cornponents :to thereby establish in the, trackwa elements a current having-in response to di zterent traflic conditions all or less than all of said components,v Y

s. A 'tra'ckway trackwa'y elements arrangedfiin blocks, a

circuit system 1 a including )OWGl'JSOlllCfi tosu) l alsin 'le'alternatin f current of a given, frequency, said current haying a plurality of. pronounced;compon'ents, variable connectionsbetween the source and the trackway element's of'a block tosel'ectivelyxretainvor suppress one orv more of said componentsto thereby establish inthe .tralckway elements of a block acuri'enthaving'al'l or less than all of said components, and a translating device,- respons ve-to traffic conditions of'another block, tocontrol. the] Variable connections. I

v 5. A Ytrackway circuit system' including 1 trackway elements arranged in blocks; a

power source to'supply a single alternating current of. a givenxfrequency,said current having a. plurality offpronouncedu compo? nents,yariable connections between the source and the trackway. elements :of a ;-bloc'k to sele'ctively retain-or suppress one .or more of said components to thereby-establish inthe -trackway elements of a block a current hay:-

ing all or less than all of said components, and a 'translat ngdevice, responslveto the presence oficurrent flowhaving one or more pronounced components in the trackway' elements of another block, to control the Variahle connections. L

,6. A trackway circuit system including: a

--trackcomposed of "traffic-' rails, 1 a; 'powe r source to supply a single alternatingturrent of a given frequenc'y, said" currentlm'v ing: a 1

plurality of pronounced components, and

tralfic-controlledariable Qconnections- :be-

tween the source and the trailic rails to selectively retainer suppress one "oi "more of said components to thereby e'stablishjiirthetraffic rails. a. current haying in response to different traflic conditionsall or less than} all of said'coinponents. A trackway circuit track composed'of traffic V x in blocks, a power source to supplya single a? components, va r'iable connections between Es -heisource and'the traffic-rails of a block to selectively retain. or suppress one or said components to thereby establish 1n the system including z u 1 s an ar nge rernating current of a giren frequency, said current having aplural ty of pronounced traffi rails ofa block acurrent hayinglall'or less than all of saidlcomponents, andatranslating device, resp'onslve'to ;trafiic;cond1t 1on s of another block, to control the variable connections. V

8. trackway circuit system including: a track composed of tra'fiic rails and arranged in blocks, a power source to supply a singlev alternating current ofa given frequency, said current having a plurality of pronounced components," variable connections between the source and the traflic rails of a block to selectivelyretain or suppress'one ormoreof said components tothereby establish in'the traffic rails ofj'a block a vcurrent having all or less than all of'said components, and a translating device, responsive to the presence of current flow having one or more pronounced components in the traffic rails of another block, to control the variable connections.

' 9; A-train control system including: trackway elements, a power source to supply a single alternating current .of a given frequency, said 'current having a plurality of pronounced. components, traffic-controlled variable connections between the source and the trackway elements to selectively retain or suppress one or more of said components to therebyf establish in the trackway elementsa and-the trackway' elements of -a block to se- 7 lectively, retain or; suppress one orVmo-re of saidcomponents to therebyestablish in the trackwayelements of a block a current-having all o'r-less than all o-fnsaid components, a

' translating-device, responsive to traffic conditions of-another block, ,to-control the; vari1- able connect ons, a vehicle, ind cating means on the vehicle, and translating, means on the vehicle selectively, responsive to the influ ence of dliferent components ofthe current inthe-trackway elements to thereby control tlieind'icatjing' "means-v to give different indications corresponding to different traflic' con- (ll lIlQIlS,

111', tram control system includingf tr'ackway element's arranged in bloksja power; sourceto supply a single alternating current of 'a given frequency, said current having a plurality" of pronounced components, variable conrrectibnsa'gbetween the v sfmrraeiand the trackway elements of avblocl:

to selectively retain or suppress one or? more said components.- to: thereby establish in mg'means to'give different indications corre-- the trackway elements ofa block a current having all or lessthan all of said components, a translating device, responsive to the presence of current flow. having one or more pronounced components 111 the trackway elements of. another block, to control the variable connections, a vehicle, indicating means onthe vehicle, and translating means on the vehicle selectively responsive to the influence of diiferentfcomponents of the current in the trackway elements to: thereby; control the indicating means to give difierent indications corresponding to different traffic conditions.

12.:A train a control system including: a track composed; of traffic rails, a power source tosupply a-single alternating current of a given frequency, said current having a plurality of pronounced components, and trafli-c-controlled variable connections between the source and the traflic rails to selectively retain or suppress one-or more ofsaid components-t0 thereby establish in the trafiic rails aicurrent having inresponse-to difi'erent traffic conditions all or lessthan all of said components, 'a' vehicle, indicating means on the vehicle,- and translatingv means on; the vehicleuselectively responsive to the.Iinfluence of different components: of thecurrent in the traffic rails to thereby control the 7 indicating means to give different indications corresponding, to difierent ,traflic conditions. 7

13. A train control system including: a track composed of traflic rails: and; arranged inblocks,a power source to supply a single alternating current of a given frequency, said current having a plurality of pronounced components, variable connections between the source and the traffi'c rails ofa block to selectively retain or suppress one or,

more of said components to thereby establish inthe trafiic rails of. -a block a current having all or less than all ofsaid c0mp.onent's,a.

translating device, responsive to traffic conditions ofanother block, to control thevariable connections, a vehicle,indicating means on the vehicle, and translating means on the vehicle selectively responsive to the influence.

of difierent components of the currentinthe tra'fiic rails to thereby control the indicating means to. give different'gindicationsg corresponding to different traflicconditionslu 14. A traincontrol system including gqa 'trackcomposed of'trafli'c rails and arranged in. blocks-, a power sourcezto. supply. a single alternating; current of. a given. frequency,

said 1 current having a plurality of pro nounced; components, varlableconnections between thegsource and-the trafiic rails of; a

block to selectively; retain or: suppress one or more of, saidcomponentstothereby estab 1 lish -in the traflic 'rails of ,a blockl a current having all, I or less; than all. of saidv e comp-01 nents, a' translating-device,responsive to the presence-of, current-flow hav ingone. or more pronounced componentsinthe 'traific rails of another block, to control the variable connections, a vehicle, indicating means on the vehicle, and translating means on the vehicle selectively responsive to the influence of different'components of the current in the traf-' fic rails to thereb control the indicating means to give di erent indications corresponding to different traific conditions.

15. A train control system including; a track, a train, a single source of current, a

trackway current modifying means, alternative paths to connect the current source to the track with the rails in series by Way of the current modifying means or independently thereof, train-carried circuit means including two electron tubes one of which is responsive only to unmodified current and the other of which is responsive only to modified current in said track, and trafiic-controlled means to connectone or the other of said paths to the track. 1 a

16. A train control system including: a track, a train, a single source of current, trackway means to modify the form of the current, alternative paths to connect the current source to the track with the rails in series by way of the current modifying means or independently thereof, train-carried circuitmeans including two electron tubes one of which is responsive only to unmodified current and the other of which is responsive only to modified current in said track, and r traflic-controlled means to connect one or the other of saidpaths to the track.

Signed at New York city, in the county of New York, and State of New York this 14th day of February, 1927. r V r ABBA G. WILLIAMSON.

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