US2736795A

US2736795A - Track circuits for supplying train control energy through crossovers

Info

Publication number: US2736795A
Application number: US180404A
Authority: US
Inventors: Harold G Witmer
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1950-08-19
Filing date: 1950-08-19
Publication date: 1956-02-28
Anticipated expiration: 1973-02-28

Description

Feb. 28. 1956 H. G. WITMER TRACK CIRCUITS FOR SUPPLYING TRAIN CONTROL ENERGY THROUGH CROSSOVERS 5 Sheets-Sheet 1 Filed Aug. 19, 1950 E INVENTOR Q H Id 6. Wz'tmer B HIS ATTORNEY Feb. 28. 1956 H. G. WITMER 2,736,795

TRACK CIRCUITS FOR SUPPLYING TRAIN CONTROL ENERGY THROUGH CROSSOVERS Filed Aug. 19, 1950 5 Sheets-Sheet 2 IO I INVENTOR HIS ATTORNEY H. G. WITMER TRACK CIRCUITS FOR SUPPLYING TRAIN CONTROL ENERGY THROUGH CROSSOVERS Feb. 28. 1956 3 Sheets-Sheet 5 Filed Aug. 19. 1950 INVENTOR filfl G. Wiimep BY HIS ATTORN EY United States Patent Office 2,736,795 Fatented Feb. 28, 1956 TRACK CIRCUITS FOR SUPPLYING TRAIN CON- TROL ENERGY THROUGH CROSSOVERS Harold G. Witmer, Edgewood, Pa., assignor to Westinghouse Air Brake Company, a corporation of Pennsylvania Application August 19, 1%0, Serial No. 130,404

14 Ciairns. (Cl. 246-43) My invention relates to track circuits for supplying train control energy through crossovers, and more particularly to track circuits for supplying energy for continuous inductive train control equipment through scissors crossovers.

Train control as here used implies the use of apparatus for inductively transferring energy from the rails to a train to reflect the condition existing on the track in advance of the train. The train carried apparatus may in-, clude brake applying devices or cab signals or both.

In railway signal systems the stretch of railway track to be equipped is formed into successive track sections by the use of insulated rail joints and as here used a track section means a given length of track the rails of which are electrically insulated from the remaining portion of the track by insulated rail joints. In train control systems of the continuous inductive type the train control energy which is an alternating or periodic current issupplied across the rails at the exit end of a track section so that the current flows down one rail, through the train shunt and back to the other rail. This means that when traflic moves over a stretch of track in either direction a source of train control energy is provided at each end of each track section and a directional means is provided to selectively connect the sources of energy to the rails according to the direction the train is moving through the track section.

Ordinarily, each track section of a main track is provided with a track circuit which includes a source of current connected across the rails at one end of the section and a track relay connected across the rails at the other end of the section, the relay being energized when the section is unoccupied and shunted when a train moves through the section. When train control equipment is used, the source of current provided for each track circuit is preferably of the character effective to control both the track relay and the train carried equipment and thus the source for the track circuit must be located at the exit end of the section. It follows that in territory provided with continuous inductive train control and train moves in either direction, a track relay and a current source preferably are provided at each end of a section and the directional means selectively connects the relays and the current sources to the rails according to the direction traflic is to move through the section.

In continuous inductive train control systems a pair of inductors, or commonly called receivers, are mounted on the train ahead of the leading pair of wheels, one over each rail for inductive relation with the rail. Each receiver picks up an electromotive force due to the alternating or periodic current of the track circuit of the section. The two receivers are connected together to add their eifects when current flows at any given instant in opposite directions in the two rails. The train carried equipment is connected to the two receivers and is ad'- justed to be effectively influenced by the electromotive forces picked up when a given minimum value of'cur re'n't flows in the rails. That is, the train carried apparatus is effectively controlled in response to a given minimum axle current flowing in the rails. Obviously, the train carried apparatus is also effectively influenced when something more than twice the given minimum value of axle current flows only in one rail and returns by a path which does not include the other rail. I

At many places of a railway, two parallel stretches of tracks are connected by a crossover, a crossover being generally defined as two turnouts with a track between their frogs arranged to form a continuous passage between two nearby and generally parallel tracks. In territories where space is limited, such asin subways, for example, scissors crossovers are provided, a scissors or double crossover being two crossovers which intersect between the connected tracks, the intersection being known as the diamond portion.

It is a problem to arrange a crossover with track sections which can be provided with track circuits that will maintain a continuous control for inductive traincontrol apparatus because of the nature of the construction of the rail frogs and because the different lengths of rails required for the crossover tracks limit the points at which insulated rail joints can be applied. Another limitation in scissors crossovers is due to the fact that insulated rail joints can be applied at only certain points in the diamond portion.

It has been customary heretofore to permit so-called cab signal ilips at crossovers. That is, there are short lengths of the rail at crossovers and particularly through scissors crossovers, where neither rail carries train control axle current and at these short rail sections there is a short period during which the control of thetrain control equipment is absent causing the cab signal to restore or flip" to its biased danger indication. As soon as the train passes this short length of rail the control for the cab signal is restored. When brake actuating devices are included in the train control equipment, the time interval that a loss of control can be tolerated due to a non-track circuited length of rail becomes very short because the brake controlling devices are arranged to apply the brakes a relatively short time interval after the loss of control from the track. Hence the problem of providing track circuited sections at crossovers becomes severe when brake controlling devices are used in the train control system. Obviously, the problem becomes extremely diflicult at scissors crossovers due to the complicated track structure. This problem is further complicated on electric railways due to the use of impedance bonds and connections used for the propulsion current because these devices tend to create unbalanced voltages which may create unwanted electromotive forces inthe train carried receivers.

Accordingly, a feature of my invention is the provision of an improved track circuit arrangement for supplying train control energy to crossovers.

Another feature of my invention is the provision of improved arrangements of track sections and track circuits for supplying train control energy through scissors crossovers.

Again, a feature of my invention is the provision of improved arrangements of track circuits for scissors crossovers and which arrangements will provide a substantially uninterrupted control influence for continuous inductive train control equipment as a train moves over either crossover ineither direction.

Other features, objects and advantages of my invention will be apparent as the specification progresses;

The foregoing features, objects and advantages of' my invention I obtain by the provision of an improved arrangement of track sections for the main and crossover tracks and an improved track circuit means for the track sections for supplying train control energy across the rails at either end of each track section. Each of the two main tracks at a crossover is provided with a track section arranged in such a manner that each main track is electrically isolated from the other main track so that there are no paths for propulsion current to flow from one main track to the other to cause an unbalancing voltage.

Each main track section is provided with a track circuit which includes a source of alternating current and an alternating current track relay at each end of the section, together with a directional means by which a track relay is connected across the rails at the entrance end of the section and a source of current is connected across the rails at the exit end of the section in accordance with the direction a train is to move through the section.

Each crossover is formed with two track sections each of which is included in a track circuit having two sources of alternating current together with connections governed by the directional selecting means in such a manner that a source of current is connected across the rails adjacent the exit end of the section according to the direction a train is to move over the crossover.

In one form of the invention one track section of each crossover is included in the track circuit of a main track section and the other crossover track section is included in the track circuit of the other main train section. In this form of the invention the rails of the crossover sections are included in the track circuit in multiple with the rails of the associated main track section. Also, the connection for supplying the current to the exit end of the section of each crossover includes the rails of one of the sections of the other crossover.

In another form of the invention, the four track sections of the scissors crossovers are included in two track circuits of the so-called single rail type. That is, a first track section of one crossover and a second section of the other crossover are included in one track circuit, and the second section of said one crossover and a first section of said other crossover are included in the second track circuit. These two crossover track circuits are of the single rail type in that certain portions of the rails of each crossover are common to both track circuits.

The two track sections of each crossover are formed adjacent to each other by the use of three pairs of insulated rail joints. The two outside pairs of insulated joints are placed one in each switch lead of the crossover where the joints of each pair can be disposed directly opposite to each other. The term switch lead is here taken to mean that part of the crossover track between the switch points of a switch and the frog in the same main track as the switch. The two track sections of each crossover are of different lengths and they are of lengths selected to permit the joints of the pair which separates the two crossover sections to be disposed one within the diamond portion and one outside the diamond portion. By this arrangement the joints of the middle pair of joints can be placed substantially opposite each other when the standard lengths of rails are used in the crossover. Thus this arrangement of the two track sections of each cross over enables the joints of each of the three pairs of insulated joints which form the sections to be placed either directly opposite or staggered a distance not greater than that which a train advances in a given time interval when moving at a given minimum speed. For example, in a given installation of automatic train control the automatic brake controlling devices are held in abeyance at speeds below 8.35 miles per hour through speed governor contacts and for speeds above 8.35 miles per hour a loss of control of the order of /2 second can be tolerated before the brake controlling devices function. Thus, a loss of axle current for a distance of the order of 50 inches is permissible before an unwanted automatic brake application takes effect. Under these circumstances the staggering of the insulated rail joints is kept at something less than 50 inches according to the track section arrangement embodying my invention.

The foregoing arrangement of the crossover track sections also enables the two extreme ends of each crossover, that is, the switch points and adjacent rails of each switch, to be included in the track circuit of the main track in which the switch is included.

I shall describe three forms of track circuits for crossovers embodying my invention and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view showing one form of track sections and track circuits embodying my invention when applied to scissors crossovers. Fig. 2 is a diagrammatic view showing another form of track sections and track circuits embodying my invention when applied to scissors crossovers. Fig. 3 is a diagrammatic view showing a modification of the track section and track circuit arrangement of Fig. 1 when applied to scissors crossovers where one of the crossovers terminates in an additional turnout.

In each of the three views like reference characters are used to designate similar parts.

Referring to Fig. 1, two parallel main tracks ET and WT of an electric railway and over which traffic may move in either direction are connected by scissors crossovers EC and WC. Each main track is formed by the usual insulated rail joints 3 which are indicated in the drawing by the symbol commonly used to indicate insulated rail joints, into a track section. The section for track ET is indicated by the reference characters D and E and that for the track WT is indicated by the reference characters F and G. Each of these track sections is one section of the automatic train control system provided for this stretch of railway, the train control system here contemplated being of the continuous inductive type which requires a source of alternating or periodic current to be connected across the rails adjacent the exit end of the section. The sections D-E and P-G are preferably of substantially the same length and each is somewhat longer than the length of the crossovers. Since trafiic may move in either direction, each main track section is provided with a track circuit that includes a source of alternating current and an alternating current track relay and a directional selecting means at each end of the section. Looking at the section 13-13, the track circuit apparatus comprises a line transformer DT', a track relay DR and a directional selector US at the left-hand end or location D; and a line transformer ET, a track relay ER and a directional selector ES at the right-hand end or location E. The primary winding of each line transformer DT and ET, as well as the primary winding of other line transformers to be referred to from time to time, is connected to a source of alternating current, such as a transmission line, the terminals of the source of alternating current being indicated on the drawings at BX and NX.

Each directional selector DS and ES, as well as other directional selectors to be referred to from time to time, include two contact members which are operated in unison between two positions. For example, the selector DS includes two contact members it) and 11 which are operable either to a right-hand position indicated by solid lines, or to a left-hand position indicated by dotted ines. Similarly, the selector ES comprises

contact members

12 and 13 which are operable to a right-hand position indicated by solid lines or to a left-hand position indicated by dotted lines. As here shown the selectors DS and ES are operated to the right-hand position when raflic is to move from left to right through the section DE and to the left-hand position when traflic is to move from right to left through the section. The means for operating the selectors DS and ES, as well as other selectors to be referred to hereinafter, may be any of several known arrangements controlling the direction of traffic over a railway track and this means is not shown in the drawings since its species arrangement rermsa ns part or my rave-mien and it is not needed for an understanding of the invention"; j

With the selectors DSand' ES set at their right-hand position to establish traffic from left'to right through the section D- E, the winding of the track relay DR is connected across the rails adjacent the entrance end D through a track transformer DTT, and a secondary winding of the line transformer ET is connected across the rails adjacent the exit end E of the section through a track transformer ETT, with the result the track relay is energized and picked up when the section is uric-ecupied. When a train enters the section from the left, the relay DR is shunted and current from the track transformer ETT flows down one rail through the train shunt and back theother rail, and this train shunt or axle current is available to influence the inductive train control receivers carried on the train,- the control being uninterrupted throughout the full length of the seetion- D-E.

When the directional selectors DS' and ES are shifted to the left-hand position, that is, to thedotted line position, to, establish traffic from right to left through the section D-E, the winding of the track relay ER is connected across the rails at the entrance end B through the track transforrner ETT and the secondary winding of the line transformer DT is connected across the rails at the now exit end D through the track transformer DTT with the result the track relay ER is energized and picked up when the section is unoccupied. When a train enters the section at the end E the track relay ER is shunted and current from the track transformer DTT flows down one rail through the train shunt and back the otherrail and the resultant aide current is available for inductively influencing the train carried apparatus, the control of the train carried apparatus being uninterrupted throughout the full length of the section. Similarly, the track circuit for the main track section F--G includes a track relay FR, a line transformer FT and a directional selector FS at the location F of the section, and a track relay GR, a line transformer GT and a directional selector GS at the end G of the section.

It is clear from an inspection of Fig. 1 taken inconnection with the description of the operation of th track circuit of section D-E, that when the selectors PS and GS are set at the left-hand position to establish traffic from the right to the left in section F--G, track relay GR is energized and picked up when the section is unoccupied by current supplied through the tract; transformer FTT to the track circuit and applied from the track circuit to the relay through the track transformer GTT. When a train enters the section at the end G, the relay GR is shunted and axle current is available for control of thetrain carried apparatus throughout the entire length of the section. Also when the selectors FS and GS are shifted to the right-hand position to establish traflic from left toright through the section F--G, the track relay PR is connected to the rails at the now entrance end P and the line transformer GT is connected to the rails adjacent the now exit end Got the section so that relay FR is energized and picked up when the section is unoccupied, but that when a train enters the section the relay PR is shunted and axle current is supplied to the rails for control of the train carried apparatus. Each of the two crossovers EC and WC is formed by three pairs of insulated rail joiuts into two adjacent track sections. For eirample, the crossover EC is formed with a first section KL by the pairs or insulated rail joints 14'15 and 16- -17, with a second L -M by the pairs of insulated joints l6-17 and 18-49. Similarly, the crossover WC is formed with a first track section NP by' the pairs of insulated joints 26- 21 and 22- -23, and with a second track section PQ by the pairs of insulated rail joints 22 -23 sad-24: 25.

I have found that the three-pair's of insulated joints i crossovers. 1 rail joints 20' 21, 2223 and 24-25 can be placed 6 14:15, 16- '-1-7 and 1s-+1l-9 can be''pl acedin' tl'fecross over EC with the joints of each pair substantially opposite each other with the standard arrangement of rail lengths provided for the crossover by locating the pairs 14 -45- and 18-19 one in each switch leadof the crossover and by locating the pair 16- 17 onewithin' the diamond portion and one outside the diamond portion of the In a similar manner, the pairs of insulated in the rails of the crossover WC- with the joints of each pair substantially oppositeeach other without any change in the standard length of the rails. It" is to be pointed outthat the joints of the pair 15''17 are staggered slightly but the staggered distance between the joints is less than the distance that a lesser axle current is permissible. In the example assumed he'reinbefore', the joints of the pair 1617 are staggered something less than 50 inches. The sanie condition existsfor thepair of

insulated joints

22 and 23 in the crossover WC.

in order to insulate the tracks sections of one cross over from those of the other crossover, I provide addi tional insulated joints at the diamond of the crossover, the

insulated rail joints

26 and 27 being placed inone 'rail of the crossover WC and the

insulated joints

28 and 2? being placed in one rail of the crossover EC. is run around cable 30 is provided at the joints 2-6 and 27 and a run-around cable 31 is provided at

joints

23 and 29. Each of these cables 38 and 31 is placed close to the associated rail and hence these cables have inductive relation with the train carried inductor when a train passes over this portion of the rail. The crossover track sections are made a part of the track circuits provided for the track sections of the main tracks and in order to connect the rails or the cross-over sections into the track circuits of the main tracksect-ions jumpers or cable connections are provided at selected points. For ex ample,

cable connectors

32 and 33 are provided to in= clude the rails of crossover section N P in the track circuit of the main track section FG. Similarly, cable connectors are provided at other points of the crosso'v'ers as will be apparent by an inspection of the drawings. It is to be pointed out that these cable connectors or jumpers are connected between the rails of the main track sections and the rails of crossover sections at points selected so that the rails of each crossover section are in multiple with the rails of one of the main tracksections as far as the control ofthe associated track relay is concerned. Furthermore, the cable connectors are placed in such a manner that a circuit path is provided for supplying current across therails of each crossover section adjacent the exit end as determined by the direction of trafiic to provide the required axle current for control of the train carriedtrain control apparatus while the train moves through that crossover section. Also", it is to be pointed out that the voltagespr'ovided for the track circuits at the crossovers are made relatively high so that the required axle current is available" in each crossover section even though there may eitist' other paths through which the track circuit current may flow at the same time: Again, these cable connectors are placed in such a manner that there is provided no path by which propulsion current may flow' from the rails of one main track to the rails of the other main track. This arrangement of cable connectors will be referred to more fully in describing the operation of trains over the crossovers.

For a move over the crossover WC from left to right, the directional selectors GS and ES are set at their right-hand position so that current is supplied to the rails at the locations G and E. Thus axle current will be obtained from the transformer at location G directly through the rails of the main section F-G and the

jumpers

34 and 35 until the first pair of wheels of the train pass the pair of joints 2121. In the section N--P of the crossover WC, axle current flows from the

transformer

22 and 23 the axle current will be lost, but as explained hereinbefore, this staggering is less than the distance permissible for the loss of control. When the leading pair of wheels pass the insulated joints 22-23, then axle current flows from the transformer at the location E through the crossover section P--Q due to the jumpers 39 and 4t) at the

joints

24 and 25, and then when the train has passed the joint 24-25 axle current is provided from the transformer at location E through the rails of the section DE. It is to be noted that the current flowing in the cable 30 which is laid close up to the rail will aid in maintaining the control of the train carried apparatus during the time the train is passing between the

joints

26 and 27.

For a move from right to left over the crossover WC, the directional selectors FS and D5 are set at their left-hand position to apply current to the rails at the locations D and F. Axle current is obtained from the transformer at location D through the rails of the main track section D-E until the first pair of wheels pass the pair of joints 24-25 due to the jumpers 6t) and 61. In the crossover section PQ axle current is obtained from location D, current flowing through the lower rail of section D-E, jumper 37, the top rail of section K-L, a run-around cable 38, the top rail of section P-Q, the train shunt, lower rail of section P-Q and thence through the top rail of section DE back to the source of supply. Axle current is lost through the staggered distance between the pair of

joints

22 and 23, but as explained hereinbefore, this distance is less than that at which a loss of control is permissible. After the train passes the

insulated joints

22 and 23, axle current is obtained for the section N-? from the transformer at location F through the top rail of section FG, jumper 33, lower rail of section N-P, cable 30, train shunt, top rail of section NP, jumper 32 and the lower rail of section E-G. When the train passes the pair of insulated joints 2ti-2l, then axle current is provided from the transformer at location F through the track rails of the main section F-G. Hence axle current is continuously provided while the train moves through the crossover WC from right to left except for the staggered distance between the pair of joints 22-23.

Similarly, axle current is provided for moves over the crossover EC in either direction except for the staggered distance between the pair of joints 16-17. For a move from left to right over the crossover EC, the selectors ES and GS are set at the right-hand position and axle current is supplied from the location E until the train passes through the crossover section KL and then from the location G through the section L--M and the final portion of the crossover. In like manner, for a move over the crossover EC from right to left, the selectors DS and F8 are set at the left-hand position and axle current is supplied from the location F for the first portion of the crossover and also for the crossover section LM and then axle current is supplied from location D through the crossover section K-L and the final portion of the crossover.

In Fig. 2, the main tracks WT and ET are joined by scissors crossovers WC and EC the same as in Fig. 1. Also the main tracks WT and ET and the crossover tracks are formed with track sections the same as in Fig. 1, except that the crossover sections do not include extra insulated rail joints at the diamond portion of the crossovers. Furthermore, the main track sections DE and F-G are included in track circuits which are substantially the same as those of Fig. 1, but the crossover sections of Fig. 2 are provided with track circuits separate from the track circuits of the main track sections. Section K-L of crossover EC and the section P-Q of the crossover WC are included in. one track circuit, and the section NP of the crossover WC and the section LM of the crossover EC are included in a second track circuit. Each of the crossover track circuits is provided with a track relay, a source of alternating current and a directional selector at each end of the section to enable moves to be made in either direction through the crossover with train control axle current supplied at the exit end of each track section.

For example, the track circuit for the sections K-L and P-Q include a track relay KR, a line transformer KT and a selector KS at the location K; and a track relay QR, a line transformer QT and a selector QS at location Q. Thus, the track relay KR, and the line transformer QT can be coupled to the track circuit, or the track relay QR and the transformer KT can be coupled to the track circuit according to the position of the selectors as determined by the direction of trafiic.

Similarly, the track circuit for the sections N-P and LM includes a track relay NR, a line transformer NT and a directional selector NS at location N; and a track relay MR, a line transformer MT and a directional selector MS at location M, and which devices are selectively connected to the rails as determined by the position of the directional selectors, as will be understood by an inspection of Fig. 2.

In Fig. 2, when a move through the crossover EC from left to right is made, the selectors ES, GS, MS and Q8 are set at the right-hand position to supply current to the rails at the locations E, G, M and Q. Axle current is first supplied from the transformer at location B through the rails of the main track section DE and the jumpers at the joints 1415. When the train moves past the pair of joints 1415 and is moving in the section K-L, axle current is supplied from the transformer at location Q through the rails of the track section P-Q which is part of the track circuit including the section K-L. When the leading pair of wheels of the train pass the insulated joints 16-17 and the train is moving in the section LM, axle current is supplied from the transformer at the location M directly through the rails of the section LM. Axle current is supplied from location G for the final portion of the crossover through the rails of the main track section F--G.

In order to make a move from right to left through the crossover EC, the directional selectors DS, FS, KS and NS are set to their left-hand position to couple the line transformers at the respective locations to the rails. Axle current is first supplied from the location F through the rails of the main. track section F-G and the jumpers at the pair of insulated joints 13-ll9. When the leading pair of Wheels moves past the insulated joints 18-19 and enters the crossover section LM the axle current is obtained from the transformer at location N through the rails of the section N-P which is a part of the track circuit including the rails of the section LM. In the crossover section K-L the axle current is obtained from the transformer at location K. Then for the remaining and last portion of the crossover axle current is obtained from the transformer at the location. D.

From the foregoing description it is to be seen that axle current is continuously supplied for moves in either direction through the crossover EC, the only interruption being at the staggered distance between the pair of insulated joints 16-47 and which distance is less than the permissible distance that a loss of control is permitted.

In order to permit a move from left to right through the crossover WC, the selectors GS, MS, QS and ES are set at their respective right-hand positions so that energy is applied at the locations G, M, Q and E with the result loclt ieh lfi until the train passes" theipsir of ins iiifedi joints 20 21, and then axle current is obtained ifr orh the t ansfcrrner at location M for thecrossoversection N P and is obtained froth the transformer 111T location Q for the crossover sec "P -Q and is obt ned from the: transformer 'at 'lo' c t ion E for the final portion of the" crossover. Whene "lnc v'e to 'be'madeoi/e1ftlie cross over we fro kigiitto 16ft theh'the'f Selec ors D's; s,

operation ofl wide the crossover track a nd; the rnin traek to insn late "the rails in the usn l rnfnner; this niodiiicait ioniof thev tiek laybllt of fig; 3, additional run rolind cables are in the circtiit aswil l he cler when 'the opieratidn of the treck circn its i s dejscribd.

is obtained form the transformer at 'the'loca tiorfEg cnir ti flowing through the"main"raiis"on the main' track and he jumpers 49 and 50 until the pair of insulated lie ros o i ,n. In order to'f'efieet control for a niove ithrofigh crossover WC from right to left, the selectlbrsRszf FS" set to c on n'ec't the associated .transforrr' ers'tothc r i or the cnrrent' frorn' the rails'of the main rgilgoilthe crossoiiIer'track; When a move from left to rightonj the crossover ECA ergit end li ofl section thr ugh the line transm n a d .Ri tr pcs i lyi t s fire y 1 ns s. nt thqc i q t 9. h m? 9 e fi f qt in vubsw al hq s m n fi n l fi s q srl for thesernoves in Fig. 1 and the description need not r W a mov f m le IQ i h qve lhq qq w WC tt 3 i 9 h madwh snal' wx fisan 3 a et, w pl urrwt; wi a sfit the F5 9??? tiye 1oat ions. Agile Current is provided from; the locaio Gv r h ra 9 t ma n trac WTqmfl @11 leading pair ofyvheels of the train moye past the pair ofinsulated joints Mi -2143f the crossover When the train is passing thrgu gh the crossoyer traclg section .N P axle current is obtained from thhe; loceitioh G thi'oii gh 1 path which incliidesl theit'op rail of the track w n cai ble mrip mi lon errail'of the j cgibmLgMfofui z' v t EQA n f i ra l, iws cfi ni eP .Qi W Q E r i i, t fi ailf i the cgi oss'vei 'se n ri P,,. opf a ll 3$hq1fi S V f cit n I; M;, i jiiinp'e'r 46 iid the lat/er rail of the rniiitr'iik" WT.

t a ocin'ted iin'ejreiisforhief tojth'e treckrai 'Aid'e current isohtai ne d firstfroln the transformer at 162121 tioii l ifitii the triinjpa'ssesg the pair of insulated joints 1 17 "a 't'th ei ldcationL of the crossoi erl'a cahi w around Sif jyvhichi laid cl ose to the top rail ofthel cross oilie'r servingi asfafpath for the cu rrentwhile thetraifiis tdf'tlitwd oesnams F and DI Whiie the trams-matingthrdu gh' thej tuinoiif of the crossover tip to the pair of ifi siilt'te'd jdints ifi lyat locatioii M, aide'cilrreiitis tained through the transformer at location F, I the" umpers atth'iihts' and 42 providing paths for ciirrent'tothe ttir'nout raii'saiid jiliiijdersat the insulated joints 18 and 1 9"15rovidingfiia'th's' for the axle current for the crossing frog poi n ftfie clps sbiefbetween"thEpfiirS'Ofjoiiits 41 42; 81618 19. While the'train is moving through the track sectio'hLM of thecros'sov'er, a path for the aideclirreiit froinfloeetion' F is"provided,a path being traced through the l'cjvfei' ail' of the main track WT; run-mum cabie 56;"top rail' of the crossover section L-M, train shlint; lower" rail of the section L--M, lower ra'ilof" the cros s QV'e r'WC,jiiiiii5er'-33 andthe m h-ail of the nihifitfhk WT. K portion of the cable' 56'is laid close toth lower th'erdsojer ECA opposite the distance between the jointslfi rig-55;, Current flowing in this rhri airoi'lii'd aid continuing the ciontr oi tr c ed eq'iiiliriint while the tram 1S inoi/in'g' between" the msuleitiiii joints 16 and 55. After the train passes the location of the insulated joint 55 axle current is obtained from the transformer at location D for the remaining portion of the crossover ECA, as will be apparent from an inspection of Fig. 3.

It follows from the above description that I have provided a track circuit arrangement for the track layout of Fig. 3 which will provide substantially continuous control of the train carried train control equipment in either direction over the main tracks or the crossover tracks of this layout.

Although I have herein shown and described but three forms of track circuits for supplying train control energy through crossovers embodying my invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, two parallel main tracks joined by scissors crossovers comprising a first and a second crossover, the rails of each said crossover formed by three pairs of insulated rail joints into two adjoining track sections, a first and a second pair of said pairs of joints of each said crossover inserted one pair in each or" the two switch leads of the crossover to enable the joints of each of said first and second pair to be disposed substantially opposite each other, the third pair of said pairs of joints of each said crossover being inserted with one joint inside the diamond portion and one joint outside the diamond portion of said crossover to enable the joints of said third pair to be substantially opposite each other, and track circuit means for each of said crossover track sections having a source of periodic train control current and provided with connections from said source to the rails adjacent a selected end of the section for supplying current from said source to the rails of said section in series when trafiic moves through the section toward said selected end.

2, In combination, two parallel main tracks joined by scissors crossovers comprising a first and a second crossover, the rails of each said crossover formed by three pairs of insulated rail joints into two adjoining track sections, a first and a second pair of said pairs of joints of each said crossover inserted one pair in each of the two switch leads of the crossover to enable the joints of each of said first and second pair to be disposed substantially opposite each other, the two track sections of each said crossover being of individual lengths with the third pair of said pairs of joints of each crossover being placed with one joint inside the diamond portion and one joint outside the diamond portion of the crossovers to enable the third pair of joints of each crossover to be substantially opposite each other, a plurality of sources of periodic train control current, and circuit meansfor each of said track sections having connections to the rails of the section and to a selected one of said sources to connect the source across the rails adjacent a selected end of the section for current to be supplied to the rails of the section in series when trafiic moves through the section toward said selected end.

3. in. combination, two parallel main tracks joined by scissors crossovers over which crossovers traffic moves in either direction, the rails of each crossover of said scissors crossover formed by three pairs of insulated rail joints into two adjoining track sections, a first and a second pair of said pairs of joints for each crossover inserted one pair in each switch lead of the crossover with the joints of each pair substantially opposite each other, the third pair of said pairs of joints of each crossover inserted in the rails for one joint to be inside the diamond portion and one outside the diamond portion of the crossovers for the joints of the third pair to be substantially opposite each other, a plurality of sources of periodic train control current, rail connections for each of said track sections having connections to the rails adjacent each end of the section, directional selector means having contact members operable to a first and a second position, and an individual one of said current sources connected to said rail connections of each end of said crossover track section through contacts of said directional selector means.

4. In combination, two main railway tracks joined by scissors crossovers, the rails of each crossover of said scissors crossovers formed by pairs of insulated rail joints into a first and a second adjoining track section, the pair of joints which separate the two sections of each said crossover inserted in the rails with one joint of the pair inside the diamond portion and one outside the diamond portion of the crossovers for the joints to be substantially opposite each other, the other pair of joints of each said track section inserted in the switch lead portion at the respective end of the respective crossover and placed substantially opposite each other; track circuit means for each of said track sections including a source of periodic train control current and connectors to the rails adjacent each end of the section, and means including contacts operable to different positions interposed in said rail connections to determine which end of each said track section a source of said current is to be connected.

5. In combination, two main railway tracks joined by scissors crossovers comprising a first and a second crossover, the rails of each said crossover formed by three pairs of insulated rail joints into a first and a second adjoining track section, a first and a second pair of said pairs of joints of each said crossover inserted in the rails one pair in each of the two switch leads of the crossover with the joints of each pair substantially opposite each other, the third pair of said pairs of joints of each said crossover inserted in the rails at the diamond portion of the crossovers with the joints of the third pair substantially opposite each other, a first and a second other insulated rail joint for each said crossover, said first and second other joint of each crossover being placed in the same rail with the first joint outside the diamond portion and the second joint inside the diamond portion of the crossovers, said first and second other joints of said first crossover insulating the first track sections of the crossovers from each other and the first and second other joints of said second crossover insulating the second track sections of the crossovers from each other, a cable runaround connected to the rails around each of said first and second other joints, track circuit means having a source of periodic train control current for each of said track sections, the track circuit means for the first section of each said crossover including connections to connect the source across the rails of the first section adjacent the junction of the two sections of the crossover, and the track circuit means of the second section of each said crossover including connections to connect the source across the rails of the second section at the end remote from the first section of the same crossover.

6. In combination, a first and a second main railway track joined by scissors crossovers comprising a first and a second crossover, the rails of each said main track formed by pairs of insulated rail joints with a track section which is adjacent to but extends beyond said crossovers, a track circuit for each of said main track sections having two sources of periodic current one connectable across the rails at the left-hand end and one connectable across the rails at the right-hand end of the section, the rails of each said crossover formed by three pairs of insulated rail joints with two adjoining track sections which extend from a selected point of one switch lead to a selected point of the other switch lead of the crossover, means including cable connectors between the rails of said first crossover and the rails of said two main tracks to supply current from the sources at the righthand ends of the two main track sections across the rails at the exit ends of the first and second track sections of said first crossover for a trafiic move from left to right over the first crossover, and other means including other cable connectors between the rails of the first and; second track sections of said second, crossbv,

the trackraila of said main tracks to supply currentifrorn said'sources atvthe left-hand ends of saidrnain traclcsec M7 In combination, a first, and a second, main railw a yj track, joined by scissors crossovers comprisinga first and a second crossover over each of which traific rnovesat timesfrom left to right, the rails of-each said main track formed by pairs of insulated railjointsgwith atraclg section which is adjacent to but extends beyond the crossovers, a source of=periodic train control current for each of said main track sections and which source is connected attimesto the rails at th''right-harid end of the section, the "rails of each of said crossoversformed by pairs of; insulated rail joints with a first" and a 'secondadjoining track section, means including the r'ailsof the second section-"of 'the second crossover and cable connectors forming: a circuit path from said source'of said first main track section to the rails of the first' section of saidfirst crossover, means including connectors between the rails of the second main track section and-the rails of thesecond'sec'tionof said first crossover forming a path' from said source of said second main track section to the rails of the second section of said first crossover, means including the rails of the second section of the second crossover and connectors forming a circuit path from said source of said second main track section to the rails of the first section of said second crossover, and means including connectors between the rails of said first main track section and the rails of said second section of said second crossover forming a circuit path from that source of said first main track section to the rails of the second section of said second crossover.

8. In combination, two main railway tracks joined by scissors crossovers having a first and a second crossover formed by pairs of insulated rail joints with two adjoining track sections, a first track circuit formed by rail connectors to include in series the rails of a first one of the sections of said first crossover and the rails of a second one of the sections of said second crossover, and a second track circuit formed by rail connectors to include in series the rails of a first one of the sections of said second crossover and the rails of a second one of the sections of said first crossover.

9. In combination, a first and a second main railway track joined by scissors crossovers having a first and a second crossover, the rails of each of said crossovers formed. by three pairs of insulated rail joints with two adjoining track sections, the joints of a first and a second pair of said pairs of joints of each crossover inserted in the rails in the first and second switch lead respectively of the crossover with the joints of each pair substantially opposite each other, the third pair of said pairs of joints of each crossover placed in the rails with one inside the diamond portion and one outside the diamond portion of said crossovers to enable the joints of said third pair to be substantially opposite each other, a first track circuit formed by rail connectors to include in series the rails of a first one of the sections of said first crossover and the rails of a second one of the sections of said second crossover, a second track circuit formed by other rail connectors to include in series the rails of the first section of said second crossover and the rails of the second section of said first crossover, and a source of periodic current for each of said track circuits having connections to the rails at a selected end of the track circuit.

10. In combination, a first and a second main railway track joined by scissors crossovers having a first and a second crossover, the rails of each of said crossovers formed by three pairs of insulated rail joints with two adjoining track sections, the joints of a first and a second pair of said pairs of joints of each crossover inserted in the rails in the first and second switch lead respectively of the e aph crossoverplacedin therails with one inside the diamond portion and oneoutside the diamond portion of.

rent or each of said track circuits one at each end of the traclc; circuit, and directionalselector means for each saidtrack circuit including contacts operable to different positions to selpctivelyrconnect,one or the other of said soprces of the .same track circuit to the rails adjacent a selected end ofth'e track circuit,

il. In: combination, a first and a second main railway trachjoined by scissors crossovers having a first and a second crossoven therails of each crossover formed by pairs of insulated rail joints into a first and a secondtrack section with the two, sections of each crossover adjoining, ,a fi rst; andja secondsingle rail track circuit for said crossover track sections, said first track circuit having rail connectors to include the rails of said first section of said first crossover and the rails of said second section ofsaid second crossover in series, said second track circuit having rail connectors to include the rails of said first track section of said second crossover and the rails of said second section of said first crossover in series, said track circuits having given portions of the rails of said crossover common to both track circuits, two sources of alternating current for each said track circuit one for each end of the circuit, and directional means including circuit controllers interposed in the connectors of each said source to the associated track circuit to selectively govern the supply of current to the track circuit according to the direction of trafiic.

12. In combination, a first, a second and a third main railway track, a crossover joining said first and third tracks and intersecting said second track by a crossing frog, said first track formed with a first track section which includes a switch of said crossover, said second track formed with a second track section which includes said crossing frog, said crossover formed by four pairs of insulated rail joints with a first, a second and a third track section which extend in the order named from said first main track to said third main track, said second and third cross-- over sections being separated by said crossing frog, a track circuit for the track section of said first and said second main tracks, each said track circuit including two sources of alternating current one at each end of the associated section, circuit means including rail cable connectors forming connections between the rails of the first main track section and the rails at each end of the first crossover section, other circuit means including other rail cable connectors forming connections between the rails of said second main track section and the rails at each end of said second and third crossover sections, and directional means having contacts operable to different positions to selectively govern the connections of said current sources for said track circuits.

13. In combination, two main railway tracks joined by scissors crossovers, each crossover of said scissors crossovers having its rails formed into a first and a second track section by pairs of insulated rail joints, said track sections of .each said crossover being adjacent to each other and having individual lengths selected for the joints of each said pair of joints forming the track sections to be disposed substantially opposite each other, track circuit means for each of said track sections including a source of periodic current and connectors beiib 'hp' ii dent res, site each other, the third pair of said pairs of joints of.

tween the source and the rails adjacent each end of the section, and directional means for each said section having contacts operable to different positions and interposed in the connectors for the same section to determine at which end of the section the source is to be connected.

14. In combination, two parallel main tracks joined by a crossover by which traflic may move between the main tracks in either direction, said crossover including two adjoining switch leads, a track section formed in each said main track by insulated rail joints and extending beyond the ends of the crossover, two adjoining track sections formed in said crossover by insulated rail joints, said two adjoining sections extending from a selected point in one switch lead to a selected point in the other switch lead of the crossover, circuit jumpers one connected between each rail of the switch leads outside of said adjoining sections and the adjacent rail of the corresponding main track to electrically connect each end of the crossover outside of the adjoining sections to the track section of the corresponding main track, a plurality of sources of periodic train control current, a plu rality of selectors one for each said current source and each selector having a circuit contact member operable to a first and a second position, a circuit connection for each end of said main track sections, each said circuit connection connected across the rails adjacent the corresponding end of the main track section and including a selected one of said current sources and the contact member of the corresponding selector, other circuit connections one for each end of said two adjoining crossover track sections, and each said other circuit connection connected across the rails adjacent the corresponding end of the crossover sections and including a selected one of said current sources and the contact member of the corresponding selector, whereby train control current is applied to the rails of the crossover for the full length of the crossover for either direction of trafiic by proper positioning of the selectors.

References Cited in the file of this patent UNITED STATES PATENTS 1,629,187 Wallace May 27, 1927 1,641,789 Thompson Sept. 6, 1927 1,684,618 Davis Sept. 18, 1928 1,810,096 Wallace June 16, 1931 2,111,501 Wight May 15, 1938 2,111,513 Phinney Mar. 15, 1938 2,144,529 Failor Jan. 17, 1939 2,203,916 Ludwig June 11, 1940 2,264,533 Johnston Dec. 2, 1941