US1483980A - Railway-traffic-controlling apparatus - Google Patents

Description

Feb. `19 1924. v

Y R. A. McANN :RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Aug, l1 1923 N N A C c mM. y mA www. lm R Q Y -i uw-: @n L RMN4 im* /c 9T Patented Feb. 19, 124.

UNITED. STATES PATENTOFFICE.

RoNALD A. IvrccANN, orI swISSvALE, ENNSYLVANIAQASSIGNOR To YfIIInUNIONl SWITCH a SIGNAL COMPANY, or swIssvALR,y PENNSYLVANIA, A CORPORATION or PENNSYLVANIA.

RAILWAY-TRAFFIC-CONTROLLING` APPARATUS. i

Application led August 11i, 1923*.` Seria1-No.656,874.

To all whom t may concern:

Be it known that I, RONALD A. MGCANN, a citizen of the `United States, residing at Swissvale, in the county of Allegheny and State of Pennsylvania, have invented certain new and usefull Improvements ina diagrammatic vaew showing one form of` apparatus embodying my invention. Fig. 2 is a view showing on an enlarged scale the vehicle carried rreceiving coils and receiving circuits shown in Fig. l. Fig. 3 is a fragmental view showing a modification' of a portion of the apparatus shown in Fig. l and also embodying my invention.

Similar reference charactersV refer to similar parts in each of the several views.

Referring irst to Fig. 1,- the reference characters U and V designate the two main tracks of a double track railway, thel nor mal direction of traiic oyereach track being indicated by the arrow associated therewith. Leading fromV the main track V' is a branch track 74 vwhich is connected with the main track by a switch l7 5. Between two main tracks U and V is a crossover 73 which is connected with the'main tracks by switches 76 and 77. It will be seen,

therefore, that in addition to main line movements on tracks Uk and V, an eastbound vehicle may proceed along main track V and into the branch track 74, whereas a' west-bound lvehicle may pass from the branch track 74 into main track V and thence through the n' crossover 73 to thek west-bound track. y v y The main line tracks'U "and V are'provided with means for supplying governing )0 energy to vehicles, whereas the branch track 74 is not so equipped. I will therefore term the main tracks U and V, positive control territory, and the branch trackt, nonpositive control territory. In the drawing I have shown this equipment on track V only, it being understood that similar equipment is provided for' trackk U but is arranged for west-bound trafiic.

The main track V is divided,by insulated joints 56 in-the track rails, into a plurality oftrack sections N-P, P-Q., etc., each of which sections is provided withv a track circuit comprising a source of current and a track relay. As here shown, the source of current for each track circuit is the secondary 57 of a transformer designated by the reference character T with an eX- ponent corresponding tothe location, which secondary 1s connected withl the track rails through a pole-changer as hereinafter eX-' plained. The primary 58 of each of these transformers isv connected` with a transmission line 59 which is constantly supplied with alternating current by a generator 60. The relay for each section is designated by thev reference characterK with an eXpof nent corresponding to the location, and 'comprises a winding '61 connected across the track rails of the section, and a cooplerating 'winding 62 constantly supplied with alternatingcurrentfby the secondary", 65 of an adjacent transformer X the priy mary 58a of which is connected with the transmission'line 59. Each relay includes a contact 63 which occupies an intermediate position when the relay is de-energized, and

'is swung to the right or to the left according as track winding 6l is supplied with current of normal or lreverse instan-v taneous relative polarity. l

Located adjacent the entrance end of each -tra'ck section is a roadside signal designated by the reference character L with an` exn ponent corresponding to the location. Each of these signals is controlled by the associated track relay K in a usual and'well known manner,but inasmuch as the control lof the signal has nothing to dov with they present invention, I have o mitted the controlling circuits from the drawings in order to simplify the disclosure as much as possible.. 'Suffice it to. say, that when a track relay i; deenergized, the associated signall indicates stop; when the track relay is energized b-y track 4current, of reverse relative polarity .(that is, when contact 63 is swung to the left), theA signaly indicates caution; and when the relay is energized by track current of normal relative polarity (that is, when the contact 63 is swung to the right), the signal indicates pr-oceed.

Interposed in each track circuit between the transformer secondary 57 and the track rails in a pole changer which is designated by the reference character Z with an eX- ponent corresponding to the location. Each of these pole-changers is operated by the adjacent signal 4 in such manner that current of normal relative polarity is supplied to the track rails of the block in the rear when the signal indicates proceed or caution, and current of reverse relative polarityis supplied to the track rails of the block in the rear when the signal indicates stop.

The apparatus thus far referred to is constructed and arranged in accordance with well known principles of railway signaling, and its operation will be understood without further explanation.

Each track section is also providedl with means for supplying line current to the track rails. For this purpose a resistance 68a is connected across the track rails at the entrance end of the section, a second resistance 68b is connected across the rails at an intermediate point in the section, and a third resistance 68c is connected across the rails at the exit end of the section. Line current is constantly supplied to the rails of each section between resistances 68l andA 68h by means of a secondary 67 on the adjacent transformer X, the terminals of which secondary are connected with the middle points of these two resistances, respectively. Line current is also at times supplied to the rails of' each section between resistances 68b and 68c by a secondary 66 on the adjacent transformer T. One terminal ofsecondary 66 is Vconstantly connected with the middle p point of resistance 68h, while the other-termin/al is at times connected with the middle point of resistance 68C through contact 63 of the track relay K for the section next in advance when the relay is energized in either direction, and also through a contact 64 operated by the signal L for such section next in advance, contact-64 being closed when the signal indicates proceed or caution, and

Y open when the signal indicates stop.

. line current is It will be seen from the foregoing, that always supplied tothe rear portion of each track section; whereas such current is supplied to the forward portion between resistances 68b and 68c when the next section is unoccupied, but not when such section is occupied.

The west-bound main track U is provided with apparatus which is` the saine as that first described for track V. rlhe only parts of this apparatus which is, shown in the drawing are the signals JP and JQ.

The reference character O designates av railway vehicle, which may be either a car or a train. Mounted on this vehicle (see Fig. 2) in front of the forward axlel are two magnetizable cores 69 and 69a located directly above the track rails l and la, respectively. Thev cores 69 and 69a are provided with windings 73 and 731L which are connected in a receiving circuit a kin such manner that the currents induced in these windings by track circuit current from transformer secondaries 57 are cumulative, whereas the currents induced in these windings by line current from secondaries 66 and 67 are in opposition and therefore create no current in circuit a. Also mounted on the vehicle O in a suitable position, such as in the rear of the forward axle, are two other niagnetizab-le cores and 70a, located directly above the track rails l and l respectively. These cores are provided with windings 173 and 173, which are included in a receiving circuit Z) in such manner that the currents induced in these windings by line current in the track rails are cumulative, whereas the currentsy induced in these windingsby track circuit current in the track rails oppose each other and therefore create no current in the circuit rlhe reference charactery A designates aA relay carried bythe vehicle O, and which I will term the main relay. As here shown, thisrelay is of the induction motor type, comprising a rotor 2 and two stator windings 3 and 3a. The windings 3 and 3L are conrtolled by the energy created in circuits a and 7), respectively, by currents in the track rails. Interposed between the receiving circuit a andthe relay winding 3 is an amplifying' device 7l, and interposed between receiving circuit and relay winding 3 is another amplifying device 72. These amplifying devices may be of any suitable forni, and they are not illustrated in detail herein because theyV form no part of they present invention. The rotor 2 of relay A operates` three circuit controlling contact fingers 4,5 and 6.y Illhe control of relay A is such that when line currenty is supplied to they receiving circuit and track circuit current of normal relative polarity is supplied to receiving circuit a, the contact lingers are swung to the right, which I will term the normal position, whereas, when the 'receiving circuit b is energized and the receiving circuit a is energized by track circuit cu-rrent of reverse relative polarity the contact fingers are swung to the left, which I will term the reverse position. When either receiving circuit a or b is deenergized, the relay` A is de-energized, so that itsv contact fingers occupy their vertical positions. It will be seen atgonce from the foregoing that Vwhen thek vehicle is traveling under a proceedsignal, the main relay A is energized iny normal direction, and that when the vehicle istraveling under a caution signal this relay.' will be energized in reverse direction, whereas, after the vehicle passes the resistance 68b in a caution block, relayA will become de-energized due to th loss of line current.

The main relay A controls speed governing mechanism represented by the reference character E, which mechanism comprises a high speed magnet H and a medium speed magnet M. The complete mechanism E is not illustrated in the drawing for the reason that it forms no part of the present invention. This mechanism is so contructed, however, that when the high speed magnet His energized, the vehicle may proceed atl full speed, such for example as 60 miles per hour; when the high speed magnet H is de-energized and the medium speed magnet M is energized, the vehicle may proceed at an intermediate speed such as 35 miles per hour; and when both magnets are de-energized a brake application will be incurred if the vehicle exceeds a xed low speed, such for example, as 15 miles per hour.

The speed governing mechanism E is controlled by the main relay A, and also by an auxiliary relay F, as Well as by a manually operable circuit controller D. rlhe aux iliary relay F is slow-releasing in character and is noramlly de-energzed. The circuit controller D, as here shown, is a push button comprising back contacts 7 7:L which are normally closed, and front contacts 8 and 8a which are normally open but are closed when the button is actuated by the engineer or operator of the Vehicle.

The high speed magnet H is provided with a primary circuit controlled by the normal contact 5 5a of relay A, this circuit being as follows: from terminal B of a suitable source of current, through wires 9, 10, and 11, normal contact 5 5a of the main relay A, wires 12 and 13, back contact 11i- 14"l of the auxiliary relay F, wires 51, 15 and 16, back contacts 7 7El of push button D, wire 17 magnet H, and wires 18 and 19 to terminal C of the same source of current. This circuit is closed only when relay F is open, push button D is in normal position,

and the main relay A is energized in normal direction, that is, when traflic conditions in advance of the vehicle are such that unretarded progress of the vehicle is permissible.

The medium speed magnet M is controlled by a reverse contact 5 5b of relay A, the circuit for this magnet being from terminal B, through wires 9, 10 and 11, contact 5 5, wire 20, magnet M, and wires 21 and 19 to terminal C. This circuit will, of course, be closed only when the vehicle is proceeding under a caution indication.`

Tn the form of apparatus here shown the vehicle is 4further provided with a cab signal S comprising four electric lamps G, Y, R and W. The lamps G, Y and R are controlled by the main relay A in such manner as to indicate traiic conditions in advance;

'the lamp Gr when illuminated indicates proceed ror high speed, the lamp Y when a 9 and 28, normal contact 4 4:L of relay A,

wire 22, lamp Gr, and wires 23 and 24 to terminal C. The circuit for the medium 4speed lamp Y is from terminal B, through wires 9 and 28, reverse contact 4 4b of relay A, wire 25, lam Y, and wires 26, 27 and 24 to terminal l. The circuit for the low speed lamp R is from terminal B, through wires 9, 10 and 29, back contact 6 6, wires 30 and 31, baclrconta'ct 32 32=1` of relay F, wire 33, lamp R, and wires 34, 27 andv 24 to terminal C. It will be seen, therefore., that lamp G is lighted when relay A is energized in normal direction, `lamp Y is lighted when yrelay A is energized in .the reverse direction, and lampl R is lighted when relay A is `cle-energized, provided that relay F is also de-energized. 4

The auxiliary relay F is provided with a pick-up circuit which passes from terminal B, through wires 9, 10 and 11, normal contact 5 5 of relay A, wires 12 and 38, contacts 8 8a of push button D, wires 39, 40 and 41, windingof relay F, and wire 42 to terminal C. It will be observed that this circuit can be closed only when the main relay A is energized in normal direction. The auxiliary relay F is further provided with a stick or holding circuit which pasess from terminal B, through wires 9, 10 and 29, back contact 6 6a of relay A, wires 30 and 31, front contact 32 32b of relay F, wires 43 and 41, winding of relay F, and wire 42 to terminal C. This circuit can be closed only. when relay F is closed and relay A is deenergized.

When relay F is closed an auxiliary circuit for the high speed magnet H is closed, which circuit passes from terminal B, through wires 9, 10 and 29, back contact 6 6a of relay A, wires 30, 35, 49 and 50, front contact 14-14b of relay 1F, wires 51, 15 and 16, bac-k contacts 7 7a of push but,-

ton D, wire 17, magnet H, and wires 18 and 19 to terminal C. It follows, therefore, that while relay F is closed and relay A is'deenergized, thevehicle may proceed at full speed. At such times, that is, while relay rent aheadI of the vehicle is reverse.

30 and" 35, front contact 36 of relay F, Wire 37, lamp V, and wires-27 and 24 to'terminal C. This lamp then gives the engineer or driver of the vehicle a constant indication of the fact that the automatic control of the vehicle is eliminated.

Reverting to the positive control appara tus associated with track V, it Willbe noted that a proceed indication is given when the relative instantaneous polarity of the track circuit current onA the right-hand rail is normal' at the same instant that the relative instantaneous polarity of the line current aheadl of the vehicle is normal.. Similarlv, a proceed indication would be given when the relative instantaneous polarity of the track circuit current on the right-hand rail is reverse at the same instant that the relative instantaneous polarity of the line cur- A caution indication is given, however, when the relative instantaneous polarity ofthe track circuit current on the' right-hand rail 'is normal at the same instant that the relative c instantaneous polarity of the line current ahead of the vehicle is reverse, and viceversa.

The branch track 74 is provided adjacent the main track V with two short track sections 7 8-79 and 79-80, each of which may,

rent by a secondary 89 on transformer Si, which secondary is vconnected with resistances 86 and 87 bridged across the rails adjacent the two ends of the section. The primaries of transformers 80, 8l and 82 are all connected across the transmission` line 59.

The transformers 80, 8l and 82 are sa connected with the rails of sections 78-79 and 79-80, that in the first of these sections the track circuit current in the upper rail is normal atthe same instant that the line current at the left-hand end of the sec'- tion is reverse, Whereasfin section 7 9 8() the track circuit current in the upper rail is reverse at the same instant that the line current at the left-hand end of'thesection is reverse. It follows, therefore, that a train passing from track V to the track 7 4, that is,

from positive control territory into the nonpositive control territory, will receive a` prosection` f 79-d80 is constantly supplied with line cur ceed indication while` passing through the ing from track 74 into track V, that is, from non-positive control territory into positive control territory, Will receive a cautionV indication` in short section T8-79.

The operation of the' apparatus in so far as traffic through the main tracksA U andi V n is concerned, will be readily understood from the foregoing Without further explanation, it being noted that during such operation the auxiliary relay F performs no function. f

I will now assume that vehicle O` proceeds; through track V tol switch 75y and thence into the branch track 74. Assuming that section PkQ andy the section to the right ofA Q' are unoccupied, the vehicle willl receive a, proceed indication until it reachesv insulated joints 78 in track 74. ln section 7 8 7 9 the vehicle will receive a stop. indication, but. this section is so short that the brakes will not be applied even though the circuit for magnet H is open at contact 5,-53 While passing through this section. ln section 7980the vehicle willv receive a proceed indication and while in this section the engi-r neer will reversey push button D, thereby closing the pick-up circuit for relay F The push button D must be held in the reverse position until the vehicle passes point 80, that is, untill 'relay A beco-mes desenergized. When this occurs the holding circuit for relay F is closed because back Contact --f of relay A is then closed and contact 32-32b of relay F is already closed.` lPush button D may then be released' and relay F will remain energized. Thek auxiliary circuitv for the high speed mag-net H is then closed, so that ,evenl though relay A; is deenergized the vehicle may proceed into andA through the non-positivecontrol territory 74 at full speedy without incurring an automatic application of the brakes.

inasmuch as both circuits for the high speed magnet include the back contact of the push button D, it follows that mag-net H is Cle-energized while this vpush button D is held .in the reverse position by the engineer, as well as while the vehicle is` passing through the short section Z8-79, as pointed out above. The speed governing and brakey control mechanism is so designed, hovv-r ever, that if magnet H' is not die-energized for a time interval greater than that determined by a delayed brake application device, the brakes will not be applied. This delayed brake application deviceA forms nol part of the present invention, and, consequently, is not illustrated inv the drawing. Such a device is fully disclosed in United States Letters Patent No. 11405552, granted t0 vFrank H. Nicholson on Feb. 7, 1922, for railway traffic controlling apparatus. It is sufficient for purposes of the present dis lll) ist

closure to state that by virtue of this device an automatic application of the brakes, due to de-energization of magnet H, is delayed for an interval of time which is approximately inversely proportional to the actual speed of the vehicle.

It will be noted that the pick-up circuit of relay F includes a normal contact of relay A but not a reverse contact or a middle contact of this relay. The reason for this is fully explained in an application by L. V. Lewis and Frank H. Nicholson, filed in the United States Patent Oiiice on Feb. 15,1922, Serial No. 5357 87 It follows from this that the engineer can. close relay F only when assing through a section giving a proceed indication into a section giving a stop indication. Consequently, if section Q or the section to the right of Q were occupied when `the vehicle O enters track 74;, it would, in

the absence of short section 79-80, be impossible for the engineer to pick-up relay F, and so it would be impossible for him to cut out the speed governing apparatus. Owing to the apparatus associated with section 7 9-80, however, I am assured that a vehicle entering track 7 4: will always receive a proceed indication very shortly after leaving track `V, so that the engineer, if alert, is always able to cut out the speed governing mechanism by proper manipulation `or' the I i push button D.

lWhen the vehicle passes from track 74 into the main track V, it will receive no indication in short section 7 9-80, because the track transformer 82 is short-circuited by the vehicle immediately after entering this section. In section 78-7 9, however, the velhiclewill receive a caution indication, thereby closing relay A in reverse direction, and so cutting the speed governing .mechanism into service. One reason for giving only a caution indication in this section 78.-79 is to prevent the driver from cutting the speed governing mechanism out of service on passing point 78 if the track between point 78 andthe crossover 73 is not equipped with means for supplying vehicle governing energy. The vehicle may then proceed through crossover 73 into the west-bound track and as soon'as it enters this track it will receive an indication depending on traflic conditions to the left of switch 76.

Referring now to Fig. 3, I have here shown a modified form of apparatus for supplying the short sections i 78-7 9 and 79-80of track 74 with vehicle governing energy. The demarcation between these 'sections is in rthis modification provided by `a bond 83 of low resistance connected across the track rails at point 79. Track circuit current is supplied to the sections by transformers 80 andr 82, asin Fig. 1, but line current is supplied to both sections by a transformer 81a, one terminal of which is connected with the resistance 84 at the lefthand end of the section, and the other terminal of which is connected with resistance 87 at the right-hand end of the section. It will be noted from the plus and minus signs applied to this view, that a vehicle moving toward the right, that is, away from positive control territory, will receive a proceed indication between points 79 and 80, whereas a vehicle moving toward the left, that is, toward positive control territory, will receive a caution indication between points 78 and 79. One advantage of the structure shown in Fig. 3 is that it eliminates the necessity` Jror insulated joints at point 79. In so far as vehicle movements are concerned, the operation of the apparatus shown in Fig. 3 is the same as the operation of the corresponding portion of the apparatus shown in Fig. 1.

It may be desirable in somel instances to provide means-under the control of the engineer Jfor closing relay F after entering non-positive control territory or vafter an emergency event, such as the failure of power or the failure of some part ofthe electrical apparatus. This may be accomplished by a slow-acting manually operable circuit controller J and an auxiliary pick-up circuit for relay F controlled by` front contacts 4:5-1-45a of this circuit controller, all as explained in the hereinbefore mentioned application Serial No. 536787. iiled by Lewis and Nicholson on Feb. 15, 1922.

Although I have herein shown and described only two forms of apparatusembodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing Jfrom the spirit and scope of my invention. j

Having thus described my invention, I claim is: y

1. Railway traffic controlling apparatus comprising positive control territory equipped with means for supplying track circuit and line energy to vehicles and `nonpositive control territory not so equipped, said means being arranged tol supply track circuit and line energy of one instantaneous l relative polarity or the other according to proceed or caution traffic conditions, two short sections of track adjacent the junction of said territories, means associated with the section 'nearer to the positive control territory for supplying track circuit and line `energy of caution relative polarity to vehicles moving toward the positive control territory, `and means associated with the other short section for supplying track circuit and line energy of proceed relative polarity to vehicles moving away from the positive control territory.

2. Railway traffic controlling apparatusL comprising positive control territory what equipped with means for supplying vehicle governing energy to vehicles, and non-positive control territory not so equipped, said means being arranged to supply energy of one relative polarity or the other according tol proceed or caution traflic conditions, two short sections of track adjacent the junction of said territories, means associated with the section nearer to the positive control territory for supplying energy of caution relative polarity to vehicles moving from non-positive into positive control territory, and means associated with the other short section for supplying energy of proceed relative polarity to vehicles moving from positive control into non-positive control territory. n

3. Railway traiiic controlling apparatus comprising positive control territory equipped with means for supplying vehicle governing energy to vehicles and non-positive control territory not so equipped, said means being arranged to supply energy of one relative polarity or the other according to proceed or caution traiiic conditions, a vehicle provided with a main relay controlled by energyreceived from the trackway and energized in normal or reverse direction according as such energy is of proceed or caution relative polarity, a normally de-energized auxiliary relay` on said vehicle, a manually operable circuit controller on said vehicle having a normally closed back contact' and a normally open front contact, governing mechanism on the vehicle normally requiring that the main relay be energized in` normal direction and the back contact of said circuit controller be closed to give a proceed indication, means :for closing said auxiliary relay when the front contact of said circuit controller is closed and said main relay is energized in normal direction but not when said main relay is energized in reverse direction, means for subsequently keeping said auxiliary relay closed if the main relay is de-energized, means effective to give a proceed indication on the vehicle when said main relay is deenergized provided said auxiliary relay and the back contact of said circuit controller` are closed, two short sections of track adjacent the junction of said positive and nonpositive control territories, means associated with the section nearer to the positive control territory for supplying energy of caution relative polarity to vehicles moving from the non-positive to the positive control territory, and means associated with the other short section of track for supplying energy of proceed relative polarity to vehicles moving from positive to non-positive control territory.

4. Railway traiiic controlling apparatus comprising positive control territory equipped with means for supplying vehicle governing energy to vehicles, and non-positive control territory not so equipped, said means being arranged to supply energy of one relative polarity or the other according to proceed or caution traiic conditions, a vehicle provided with a main relay controlled by energy received from the trackway and energized in normal or reverse direction according as such energy is of proceed or'caution polarity, speed governing mech'ainsm controlled by said relay forpermitting high, medium or low speed according as the relay is energized in proceed or caution direction or is de-energized, an auxiliary relay on said vehicle, a pick-up circuit for said auxiliary relay including a manually operable circuit controller and a proceed contact of said main relay, a holding circuit for said auxiliary relay including a contact closed when said main relay is de-energized, means for causing said speed governing mechanism to permit high speed when said auxiliary relay is energized, two short sections of track adjacent the junction of said positive and non-positive control territories, means associated with the section nearer to the positive controlv territory for supplying energy of caution relative polarity to vehicles moving from the non-positive to the positive control territory, and means associated with the other short section of track for supplying energy of proceed relative polarity to vehicles moving from positive to non-positive control territory.

5. Railway traffic controllingv apparatus comprising a main track and a branch track, the main track being equipped with means for supplying to vehicles governing energy of one relative polarity or the other according to proceed or caution conditions and the branch track not being so equipped, two short sections of track in the branch track adjacent the main track,v means associated with the short section nearer the main track for supplying energy of caution relative polarity to vehicles approaching the main track, and means associated with the other short section for supplying energy of proceed relative polarity to vehicles leaving the main track.

6. Railway 'tramo controlling apparatus comprising a main track and a branch track, the main. track being equipped. with means for supplying track circuit and line energy to vehicles and the branch track not being so equipped, said means being arranged to supply track circuit and line energy of one instantaneous relative polarity or the other according to proceed or caution traic conditions, two short sections of track in the branch track adjacent the junction of said two tracks, means associated with the section nearer to the main track for supplying track circuit and line energy of caution relative polarity to vehicles approaching the. main track, and means associated with the other section for supplying track circuit and line energy of proceed relative polarity to vehicles moving away from the main track.

7 Railway traiic controlling apparatus comprising a main track and a branch track, the main track being equipped with means for supplying track circuit and line energy to vehicles and the branch track not being so equipped, said means being arranged to supply track circuit and line energy of one instantaneous relative polarity or the vother according to proceed or caution traic conditions, two short sections of track in the branch track adjacent the junction of said two tracks, said sections being demarked by a bond of low resistance connected across the rails, a track tarnsformer at each end of the said sections, a line transformer connected with both rails at one end of said sections and also with both rails at the other end of said sections, said track and line transformers being of such relative polarities that a vehicle approaching the main track receives energy of caution relative polarity while in the section nearer to the main track, whereas the vehicle leaving the main track receives energy of proceed relative polarity while in the other section. y

In testimony whereof I, aiix my signature.

RONALD A. MCCANN.

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