US2265351A

US2265351A - Switch and signal control system for railroads

Info

Publication number: US2265351A
Application number: US330534A
Authority: US
Inventors: Nelson B Coley
Original assignee: General Railway Signal Co
Current assignee: SPX Corp
Priority date: 1940-04-19
Filing date: 1940-04-19
Publication date: 1941-12-09
Anticipated expiration: 1958-12-09

Description

Dec. 9', N. B. COLEY SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS V Filed April .9, 1940 10 Sheets-Sheet 1 Fl G. LA. ZSML SSML 4$ML 10MB 10x5 2A 5NK LBNB *QL J C 1. L C .i

I I 25K 2BNK ZEN/12K a 4mm 4BN/RK INVENTO ATTORNEY Dec. 9, 1941. N, B, COLBY 2,265,351

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed April 19, 1940 10 Sheets-Sheet 2 ATTORNEY Dec. 9, 1941. N." B. coLEY SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed April 19, 1940 10 sheets-sheet 3 1N2 9 R E ATTORNEY N. B. COLEY Dec. 9, 1941.

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed April 19, 1940 10 Sheets-Sheet 4 1 E 5R6 mm o To L um v at Em 8 1 A 36 F $3 NE 8. 3 52 3 m v3 7 S AGE 3 -23 2 20 96 QG h 3 ufifi 3 a 5 5 o.

who Paw FE NEE JM izuE TV E: 8% .T

3 a? HH U 15 HH T mai 32" NH E u 9: E h 36 Si h .E 9 5 hw 26 n Rm T hm ATTORNEY Dec. 9, 1941. N. B. COLEY 2,255,351

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed April 19, 1940 10 Sheets-Sheet 6 FIG 5.A.

(PH) 101212 M? J(FL+). '2 mm INVENTO BY WM 4, ATTORNEY Dec. 9, 1941.

I N. B. coLEY I 2,265,351 SWITCH AND SIGNAL CONTROL SYSTEM FOR- RAILROADS Filed April 19, 1940 10 Sheets-Sheet 7 F|ca.5.B;

ATTORNEY N. B. COLEY Dec, 9, 1941.

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS 1o sheets-sheet 8 ATTORNEY Filed April 19, 1940 N. B. COLEY Dec. 9, 1941.

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed April 19, 1940 10 Sheets-Sheet 9 ATTORNEY N. B. COLEY Dec. 9, 1941.

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed April 19, 1940 10 Sheets-Sheet 10 Ii E O NCRH mm Patented Dec. 9,

SYVITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Nelson B. Coley, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application April 19, 1940, Serial-No. 330,534

18 Claims.

This invention relates to switch and signal control systems for railroads, and it more particularly pertains to a switch and signal control system of the entrance-exit type.

An entrance-exit switch and signal control system is characterized by having a control machine at a tower or control office which has a control panel upon which is a miniature track diagram of the track layout for which the system is provided, such diagram having control buttons disposed thereon at points corresponding to the entrance and exit ends of routes extending through the track layout as defined by the location of the various signals. The establishment oi each route extending through the track layout. is effected responsive to the actuation by an operator of the control buttons for the respective entrance and exit ends thereof. In order that an operator may govern the establishment of routes intelligently in accordance with traflic conditions, suitable indications are provided along the diagram relative to routes established, the condition of the track switches and signals, and the occupancy of the various track sections.

In some entrance-exit systems such as the system provided by the present invention, it is necessary to designate only the extreme entrance and exit ends of a route which includes one or more intermediate signals in order to effect the setting up of that route. A route when set up in such a manner is said to be established vby end-to-end control, and is conveniently called a through route. To facilitate the description of the present invention, each group of track switches by which routes not involving intermediate signals can be established, is conveniently called an interlocked group. Thus, a through route extends through a plurality of interlocked groups.

An object of the present invention is to provide an entrance-exit type of system requiring a minimum number of relays and circuit selections which can be readily and effectively applied to the governing of traffic through practically any track layout under all operating conditions required in standard railway practice.

Another object of the present invention is to provide in an entrance-exit system an improved route selecting or route establishing. means whereby a definite number of switch position selecting relays is provided for selecting the normal and reverse operation of the track switches of each crossover and each single track switch in the track layout, irrespective of the number of different routes that can be established extendbe established when available in preference toing over each of such track switches. For the selective energization of each of such switch position selecting relays, two circuit networks are provided for each of the interlocked groups, one

circuit network being energized responsive to the designation of an entrance or exit pomt for one end of the interlocked group, and the other circuit network being energized responsive to the designation of an entrance or exit point for the opposite 'end of that interlocked group.

Another object of the present invention is to allow the establishment of a route only if such route is available for use. Such object is accomplished by rendering the designation of an exit point effective for applying energy to the network for the energization of switch position selecting relays only if an exit relay for that exit point is energized. The energization of such exit relay is dependent upon its being conditioned for energization responsive to entrance designation, and

Another object of the present invention is to provide that the route establishing means is effective to select a preferred. one of alternative or:

optional routes extending between given entrance and exit points. If such preferred route is rendered unavailable, another of the optional routes is automatically established in accordance with entrance and exit designation of the ends of that route; thus, where several optional routes are involved, a route will always be established as long as any one of such routes is available for use.

A general rule by which the system can operatev relative to alternative or optional routes is that the available route diverging nearest the entrance point is set up in preference to the other routes.

This rule does not apply, however, to run-around routes as in such cases the most direct available,

route is generally given preference.

Another object of the present invention is to adapt the entrance-exit system to conditions often encountered in practice Where a particular one of a plurality of optional routes 15 desired to ing ultimately efiective after exit designation to cause route establishment past that intermediate signal as if the control buttons for the entrance and exit points at that intermediate signal had been actuated, if that intermediate signal is included in the through route to be established between designated entrance and exit points.

power operation of only the track switches that are required in each route being established, even though the normal positions of some of the track switches are definitely selected:responsive to en'- trance designation, if such track switches can be trailed in normal positions in routes available for use emanating from that entrance point; -That is, responsive to designation of an entrance point,

energy is applied to the circuit network which is energized responsive to entrance or exit designe tion at that end'of the interlockedgroup, which effects-the energization of a relay for eachffacing point switch that can be included in'either a normal or a reverse position in a'route available for use emanating from that entrance point, and for each track switch that can-be trailed in a normalposition in a route availablefor use em,- anating from that, entrance point. The power operation of a track switch, however, is not effected until a second relay for that track switch or crossover is picked up when energized in the other circuit network responsive to the picking up'of an exit relay upon the subsequent designatiton of an exit point. The picking up of the exit relay under such conditions causes theenergiza tion ,of relays in the circuit network responsive to exit designation for that end of the interlock group, and the energization of those relays. is efiected in a manner similar. to the energization of switch position selecting relays responsive to entrance designation except that circuit points of conflict have been established in .the network because of the energization of relays in the net.- work energized responsive to entrance designa-. tion in the setting up of that route. Such circuit points of conflict provide. that the energization of switchcontrol relays responsive to the picking Another object of the present invention is to provide a system'for clearly displaying indications along the track diagram in accordance with the response of the circuit network in the establishment of routes to keep the operator well informed as to the conditions which he must consider in intelligently manipulating the entrance and eXit control buttons for the establishment of routes. Such indications are provided in the form of relatively continuous lines of light provided along the'track diagram to correspond with routes established, and to distinctively indicate the presence of trains in such routes.

, It' is believed that other objects and purposes of the-present invention will-be apparent and more readily understood from reference to-theaccompanying drawings and. as they are pointed out during the descriptionof the present invention. I

' Indesoribing the invention in' detail reference lustrate the' miniature track diagram: provided up of an exit relay is limited to relays correspending to, a route which has been preselected by the switch position selecting relays responsive to entrance designation extending between'the.

designated entrance and exit points; The power operation of thetrack switches for each of the crossovers and each of the single track switches is effected responsive to route'establishme'nt only; when two switch position selecting relays for such' track switch or crossover, one in each circuitnet} work, are energized. The combination of the two relays energized determines as by a code what the position ofthe track switch shall be as one.

of those relays" is energized for both the normal and. reverseoperation of its track switch, and thus requires the cooperation of a second relay to determine to .what position the track switch shall be operated. 1

Another object of the present invention is to provide in'the system means by which a route cluded. in an available route emanating from that entrancepoint, thelenergization of that'relay befor this embodiment of the present invention together with the route establishing means pro-vid-.

ed'for automatically selecting each route to be set up in accordance .with'the designation of the cluded in the track layout forwhich this embodi- I ment of the present invention is provided? Figs. 3A and 3B illustrate the tracklayout for which, the entrance-exit system is Drovid'ed together with control circuits relative to the control.

ofthe signalsofsuch'track layout.

'Figmi illustrates approach and route locking meansas applied to the entrance-exit systemiof the'present invention Figs. 5A- and 5B, when illustrate the means of control provided for indicator lamps for .the display of indications along the track diagram illustrated in Fig. IA; and I Figs;"6A, 6B and BC; when placedend-to-end,

illustrate theuse'of end-to-end control .in' the entrance-exit system provided by the present in ventiorL- I 7 Reference is made in the. description of the. present invention from time to time, to functions a common to all parts of a similar; kind or class by the useof letter reference characters common to such parts without their preceding numerals. Such reference is to be understood to apply to parts designated in'the drawings by reference-1 characters that 'are similar. except for preceding numerals,

In order tosinip'lify the ldisclosureof thepres} pla c ed side by side,

ent invention, various diagrammatic and conventional illustrations generally known to those familiar with the art have been employed in the drawings, rather than attempting to show the particular construction and arrangement of parts actually used in practice. The various relays and contacts are therefore shown in a conventional manner, certain circuit details well known to those familiar with the art are merely indicated by dotted lines, and symbols are used to indicate the connections to the terminals of the batteries or other sources of electric current. In order to facilitate in the arrangement of the circuits in the drawings, some of such circuits have been shown in the conventional written circuit manner, the reference character provided above each of the relay contacts being used to identify the particular relay with which such contact is associated.

The symbols and are employed to indicate the positive and negative terminals respectively of suitable batteries or other sources of direct current, and the circuits with which such symbols are used always have current flowing in the same direction. The symbol (FL+) is used to indicate the connection with the positive terminal of a frequently interrupted source of energy. If alternating current is used instead of direct current, the symbols are to be considered as representative of instantaneous relative polarities.

Track layout-{t is to be understood that the present invention is adapted for use with practically any type of track layout encountered in practice, and that the comparatively simple track layout illustrated in Fig. 3A for which this embodiment of the present invention is provided, illustrates merely a typical application of the system, and such track layout can also be considered as being only a particular part'or unit of a complex system, other units or interlocked groups being connected, for example, as is typically illustrated in the track layout shown in Fig. 60.

With reference to Fig. 3A, the track layout consists of two parallel tracks interconnected by crossovers -2 and 4, and a third track connected to the lower one of such main tracks by a single track switch 3;

With reference to Fig. 6C, a track layout corresponding to that shown in Fig. 3A is illustrated as having the main tracks extended to the right past intermediate signals to provide an adjoining interlocked group, the main tracks of that group being interconnected by crossovers 5 and 6. Each of the track switches in the two track layouts illustrated is power operated by a switch machine SM of a type generally employed in practice such, for example, as the switch machine shown in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923. If that type of a switch machine is employed, for each ofthe track switches its motor should preferably be governed in a suitable means to provide overload protection and features generally required in practice with respect to the control of switch machine motors, such, for example, as is shown in the patent to W. H; Hoppe et al., Patent No. 1,877,876, dated September 20, 1932. The track switches ZAW and 213W, therefore, for the A and B ends of the crossover 2, for example, are power operated by the switch machines ZASM and EBSM respectively.

A- polar neutral relay WP is employed in the usual manner for repeating. the locked position of the track switches. of each of the crossovers, 75; ing. to the track; layout iorwhichthe. systemis and for the single track,,in correspondence with the locked pQSition of, the switch machine or switch machines associated therewith. Such WP relay is energized with one polarity when the track switch or track switches with which it is associated are in a normal locked position, in correspondence with the normal locked position of the switch machine for such track switch or 'track switches; and such WP relay is energized with the opposite'polarity when correspondence is established between the switch machines and track switches in their reverse locked positions. Each, of the WP relays is energized only when either of such conditions is fulfilled. For effecting such control of each of the WP relays, the

circuits therefore generally selected by contacts provided on, a point detector contact mechanism such as is shown, for example, in the patent to C. S. Bushnell, Patent No. 1,517,236, dated November 25, 1924.

Signals are provided for governing traflic through the track layout illustrated in Fig. 3A, in both directions, signals l0, HA, HE, IS, I6 and 2| being provided for governing east bound trafiic through the track layout to the right, and sig- 'nals [2A, I2B, l3, l4, l9 and 20 being provided for governing west bound traflic to the left.

The signals illustrated are of the search light type having their indications governed in accordance with the distinctive energization, or the deenergization of an operating mechanism which can be, for example, of the type disclosed in the patent to O. S. Field, Patent No. 1,835,150, dated December 8, 1931. It is to be understood that ;other types of signals such as signals having individual color lamp units, position light signals, and semaphore signals can as well be employed, and it is to be further understood that the arrangement of the signals along the track layout can vary in accordance with the requirements of practice.

Of the signals illustrated in Fig. 3A, it is assumed that. they are all of the low speed type displaying a yellow indication for proceed and a red indication, for stop except for the signals HA and I 2A which in addition to those indications can display a green higher speed indication selected dependent upon the clearing of the next signal in advance. The signals HB and HE are of the low speed type generally known as call-on signals.

Thetrack layout illustrated in Fig. 3A is shown to be divided into track sections in the usual manner, the upper track being divided into

track sections

2T, 3T, 4T and ST, and the lower one of the main tracks being divided into

track sections

8T, 9T, WT and l IT. It is to be understood that each of the track sections is provided with a track circuit (not shown) in the usual manner for the control of a track relay TR associated vided has the same general type of track circuits and signals, all of the signals, for simplicity being assumed to be of the low speed type.

Control. machine.The control machine providedin a tower or control office generallylocated near the track layout for which the system is,

provided has a control panel upon which is. constructed a miniature track, diagram correspond- Fig. 1A is constructed on the control panel of the control machine to correspond to the track layout illustrated in Fig. 3A, such diagram having its trackway made up of a series of linear'translucent inserts in the panel which can be illuminated. by indicator lamps secured to the back of thepanel. 1 The position of the translucent inserts alongthe trackway of the diagram is determined by the type of indications desired to be displayed in a manner to be more fully described when considered in detail the indications provided. Entrance and exit buttons NB and X3 respectively are provided at points on the miniature track diagram corresponding toentrance and exit points at the track layout as defined by the'location of the various signals, The portions of the track diagram extending between the buttons and between the translucent inserts is preferably painted lunar white to correspond with the color of the translucent inserts, in order that the diagram may appear continuous in effect when the lamps behind the translucent inserts are extinguished.

Each of the entrance buttons NB used for designation of entrance points in the establishment of routes is of acharacter having several distinctive'operating positions, and such button can be constructed, for example,as shown in the prior application of J. F. Merkel, Ser. No. 158,720, filed August 12, 1937., Each of such buttons is'normally biased to a normal position from which it can be either depressed or pulled out. There is a contact associated therewith which is normally closed,and is maintained closed when the button is depressed, but is opened when the button is pulled out; and there isanother contact whichis closed only when such button is in its depressed position. Whenever a call-on signal is provided in the track layout such, for example, as the signal B (see Fig. 3A). the entrance button NB associated therewith has a distinctiverotated-position for selecting the control of such signaLand hasa contactrclosed in that rotated position.

Each of the exit buttons XB used for designation of its: particular exit point in the establishment of routes is of the self-restoring push button type having a contact closed only when such 1 button is depressed;

Although separate buttons have been, shown in this embodiment of thepresent invention for use in designating the respective entrance and ex it.

endsof each route, it is to be understood thata single button can as well be provided for both entrance and exit designation for each of the route ends-if a sufficient number of distinctive operating positions is provided to fulfill the 'circuit requirements, or if v circuit means is provided for distinguishing between the actuation of that button for designation of respective entrance and exit points at that route end. V

provided. Thus thetrack diagram illustrated in which will be more readily apparent from refer-' ence to the more specific description of the auxiliary control as hereinafter pointed out. System devices.--An entrance relay NR is associated with each of the entrance points, and is energized responsive'to theactuation of the entrance button NB for that entrance point. Such relay'NR, when energized, is maintained energizedby a stick circuit, dependent for restoration either upon passage of a train, or upon manual designation of such restoration by the pulling out of the entrance button NB for that entrance point.

In a similar manner an exit relay XR is associated with each of the exit points, such relay being picked up when the exit button XB for that exit point is depressed subsequent to the designation of. an entrance point, only if there is an available route extending between those entrance and exit points. Such exit relay when picked up is main tained energized by a stick circuit, dependent upon the energized condition of the entrance'relay NR for the entrance end of the route having its entrance and exit points designated. I Each of the crossovers in the track layouthas associated therewith four neutral switch position selecting relays which are selectively responsive to entrance'and exit designation in the establishmentof routes, there being three of such'relays provided for each of the single track switches. Of the four switch position selecting relays provided for each of the: crossovers two of the relays are more directly associated with the A end of the crossover and the other two'relays are more directly associated with the Bend of the crossover. 1 One of the relays for the A end of the j crossover isresponsive to designation of an entrance or exit point for a particular end of the entrance or exit point at the opposite'end of the interlocked group;

The relay AC is provided for the facing point of the track switch at the A end of the crossover and is therefore energizedin the establishment of a route over that end of the crossover with the track switch in either a normal or a'reverse po sition, while therelay -AN for that end of the crossover is provided'for the trailed positio'n of the track switch and is energized only in the establishment of a route over that end of the crossover in a normal position. The relays BC and EN function in a relatively similar manner for the B end of the crossover, relay BC being com 7 mon to normal and reverse positions of the track switches, of the crossover. ample, for the A end of crossover 2, the relay ZAC is energized responsive to entrance designation for east bound traiiic through the track lay,-.

out or responsive to exit designation for the same fore-,jn order to allow' the individual operation of each of the single'track switches and'the track operation of each of the single track switches and the trackswitches of. each crossover in accord ance with the selective energization of the switch 7, position selecting relays AC, AN, BN and BC. w

route end, and the relay ZAN is energized responsive to entrance designation for west bound tra f-, fic through the track'layout or responsive to exit designation for that route end. I I

Withreference to Fig.2, a polar neutral relay W2 is provided for moredirectly governing the Such relay WZ is used in order to provide desirableyieatures with; respect to the control of thetrack switches'as hereinafter pointed out,

Therefore, for ex such, for example, as a means for reversing the track switch in midstroke.

A relay NCR, and a relay RCR is provided for each of the crossovers and for each of the single track switches for repeating the correspondence of the track switches of the crossover or of the single track switch with the position called for such crossover or single track switch by the cu ergiz'ation of the switch position selecting relays.

With reference to Fig. 3A, a signal control relay G is provided for governing the clearing of each of the respective signals at the track layout after each route is established. With reference to Fig. 3B, each of the signal mechanisms is provided with Contacts for selecting the control of signal repeater relays GYP and RP, the relay RP being normally energized to correspond with the red stop indication normally displayed by the signal, and the relay GYP being energized only when the signal has been cleared.

With reference to Fig. 4, various relays are provided associated with the locking, the relays ES and WS being normally energized relays associated with the route locking, the relays AS being normally energized relays associated with the approach and time looking, and the relays L, LA and LB being used as means of repeating the various types of locking provided. Each of the relays AS has a thermal relay TH associated therewith in the usual manner.

' Having thus considered the general function of the various parts of the system, it is believed expedient to consider the mode of operation of th system 'and the principles involved in accordance with various typical operating conditions.

Operation Normal conditions.It is assumed that normal conditions of the system exist when the track layout is unoccupied by trains, when there are no routes established through the track layout, or partially established, and when the signals governing traflic over the routesare all at stop. In accordance with such conditions, the

indicator lamps for display of the indications are all normally deenergized. The track switches will of course assume the position in which they were last required in the last route established, and, for the purpose of the present disclosure,

it is assumed that the last routes established were through routes on the two main tracks, thus providing that the track switches are all in their normal positions under the assumed normal conditions. The relays associated with the route selecting or route establishing means are all normally deenergized, and the relays which are energized under normal conditions are those relays relative to the looking as shown in Fig. 4 in addition to the track relays TR, track repeater relays TP, and switch repeating relays W'P which are of course normally energized in the usual manner.

Route' establishing means.'-The route establishing means as illustrated in Figs. 1A and 13 consists; generally speaking, of two circuit networks which are responsive for the energizatio'n of switch position selecting relays to the energization of entrance and exit relays NR and KR which in turn are energized responsive to respective entrance and exit designation in the setting up of each desired route extending through the track layout. The circuit networks fulfill two principal purposes, one of which is to provide selective ener'gization for the exit relays XR to insure that such relays are picked up only when routes are available extending between en trance and exit points, and a second purpose of such circuit networks is to provide a circuit means for selectively energizing the switch position selecting relays for each of the crossovers and each of the single track switches, such two general purposes of the circuit networks being interrelated because of the selectiveenerg'ization of the switch position selecting relays governs the circuit portions through the circuit network by which the exit relays XR are conditioned to render their picking up effective upon exitdesignation. More specifically, one of the circuit networks has feed points comparable to the entrance and exit points at the left hand or west end of th track layout, and such feed points cause energyto flow in the circuit network when an entrance point is designated through each portion of the circuit network which corresponds to a route available for use emanating from such entrance point. If there is a route emanating from that entrance point available for use extending to an exit point, energy is fed throughout the length of the circuit network to condition the relay XR for that exit point in such a manner that it may be picked up responsive to the actuation of the exit button XB for that exit point. It is furthermore provided that as many exit relays are conditioned for energization in that manner as could be included in a route available for use emanating from the designated entrance point.

In feeding energy through the circuit network from th front contact of an entrance relay NR responsive to entrance designation, a common switch position selecting relay AC or BC is picked up for each track switch facing such entrance point, if that track switch can be included in a route available for use emanating from that entrance point. similarly, energy feeding through the circuitnetwork'responsive to entrance designation causes the picking up of a relay AN or BN for each track switch that can be trailed in a normal position in a route available for use emanating from such designated entrance point. The response of the switch position selecting relay, to entrance designation establishes conditioning circuits for the exit relays XR in such a manner that each exit relay XR is conditioned so that it can be picked up upon exit designation for that exit point, only if there is an available route extending from the designated entrance point to that exit point.

When an exit relay XR is energized in the establishment-of a route, energy is applied to the other circuit n twork for the energization of the switch position selecting relays to effect the selective energization of relays to complete the selection or establishment of the route. The energization of switch position selecting relay responsive to the picking up of each of the exit relays is effected in a manner comparable to the conditioning responsiv to entrance designation, the same circuits being used as are used when an entrance point is designated at that route end. The selective energization of such relays responsive to exit designation, however, instead of being effected for each route emanating from such point is effective only for the route correspending with the one preselected upon entrance designation. Thus, the response to the relays to entrance designation establishes circuit points of conflict which in effect provide that only one route is available for selection responsive to exit designation, such route corresponding with to I4; He first depresses the entrance button I HNB for designation of the entrance point for thatroute, and responsive to such designation the relay 1 lNR ispicked up, and the picking up of that relay causes energy to feed through the circuit network energized in accordance with entrance and exit designation for that end of the interlocked group. Such energy feeding through the network causes the picking up of relay ZBN because the B end of the crossover 2 is trailed in a normal position in a route emanating from the entrance point atl i. The picking up of relay 2BN causes the picking up of relay 3A0 because the single track switch. 3 has'its facing point included in a route emanating from the designated entrance point, and the picking up of that relay closes a circuit which feeds energy to the V winding of relay. I4XR. The picking up of relay 3AC, also feeds energy along the branch of the Assume, after relay I4XR has been conditioned for energization in the manner described that an operator depresses the exit button MXB for designation *of the exit end of the route extending frorn II to l4, and the "depression of that button causes the picking up of relay MXR. inasmuch as it is assumed the route from to. l4 to be available. Upon the picking up of relay I4XR, energy is applied to a feed point of the circuit network which is energized responsive to the designation of route ends'for, the right hand end of the track layout, and energy feeding through such circuit network causes the picking up of the relay 330 for the track switch 3. Responsive to the picking up of that relay energy is applied to the relay 2B0 for the track switch at the B end of crossover 2 which faces theiexit point designated, thus completing the selection of the route extending from I l to I4. It will be noted that the picking up of relay 213C cannot pass energy on through the branch of the network corresponding to the track portion extending over crossover 2 because such branch of the circuit network has been opened initially by the picking up of relay ZBN responsive to the picking up of relay IINR.

To consider specifically the circuitsby which the relays are energized in the establishment of the route from II to I4, the relay! INR is picked up responsive to the depression of button IINB for designation of the entrance end of that route by the energization of a circuit closed from including front contact 39 of relay 9TH, contact 3|, of button II NB closed in a depressed position, back contact 32 of relay IICNR, and winding of relay IINR, to The picking up of that re lay closes a stick circuit extending from including front contact 30 of relay 9TB, contact 3| of button IINB' closed in both normal and depressed positions front contact 33 of relay l INR, and winding-of relay l INR, to The picking winding of relay MXR. A circuit is alsoclosed at up of relay IINR causes the picking up of relay 2BN by the energization of a circuit closed from including front contact 34 .of relay HNR, back contact 35 of relay 1 DB, back contact 36 of relay 2A0, and lower winding of relay ZEN, to The picking up of relay 2BN causes the picking up of relay 3A0 by the energizationof a circuit closed from including front contact 34 of relay IIN'R, back contact 35 of relay HXR, back contact 36 of relay 2A0, front contact 37' of relay ZBN, and lower winding of relay 3AC, to When relay 3AC is picked up, a circuit is closed for conditioning the relay MXR for energization extending from including front contact 34 of relay IINR, back contact 35 of relay l IXR, back contact 36 of relay ZAC, front contact 37 of relay ZBN, front contact 38 of relay3AC, and back contact 39 of relay 3AN, wire 40, to the of relayAAC, and lower winding of relay 4BN,

to The picking up of relay 4BN'closes a circuit in an obvious manner extending to the winding 'of relay I3XR. to condition that relay so that it can be picked up if an exit point be desig'-' nated at l3.,

Assuming the operator depresses the button I 4XB after the conditioning of relay I4XR has become effective, the relay MXR is picked upby the energization of a circuit extending from including front contact 34 of relay IINR, back contact 35 of relay mm, back contact 33 of relay ZAC, front contact 31 of relay ZBN, front contact 38 of relay 3AC, back contact 39 of relay 3AN, wire 40, winding of relay I4XR, backbontact 44 of relay MNR, and back contact 45 of button I4XB closed in a depressed position, to The picking up of that relay closes a stick circuit at front contact 46 to shunt

contacts

44 and 45 out of the circuit'just described.

Responsive to the picking up of relay MXR, a circuit is closed to cause the picking up of relay 313C extending from including front contact 41 of relay MXR, wire 48, back contact 49 of relay 3AN, and lower winding of relay 3BC, to The picking up of relay 3BC causes the picking up of relay ZBC by the closing of a circuit extending from including front contact 4'! V of relay i4XR, wire 48, back contact 49 of relay 3AN, front contact 50 of relay 3BC, back contact 5| of relay -3AN, and lower winding of relay 230, to V The position of the track switches selected in accordance with the selective energization of the switch position selecting relays in the establishment of a route is dependent upon the combination of two relays energized for each of the single track switches or each of the crossovers, such combination determining whether such track switch or switches are to be operated to normal or reverse positions. That is, for example, the joint energization of the relays 2BN and 2130 causes the operation of the track switches of crossover 2 tonormal positions, the joint energization of the relays ZAC and 2AN causes the operation of the track switches of crossover 2 to normal positions, and the joint energization of relays ZAC and ZBC with relays 2AN and 2BN deenergized causes the operation of the track switches of crossover 2 tojreverse positions. The manner in which energy is applied'to'the switch machines for the power operation of the track switches in accordance with the energization of the switch position selecting relays in such combinations is hereinafter considered more in detail.

With reference to the circuits which have just been described it will be noted that, before energy can be applied to the switch position selecting relay ZBN, it is checked that the track switches of crossover 2 are not called for in their reverse positions. Thus, if relays ZAC and 23C were energized and relays MN and ZBN deenergized at that time, energy would be prevented from feeding through the network from front contact 34 of relay HNR to the lower winding of relay ZBN. Such mode of operation establishes so called circuit points of conflict in the networks at points comparable to points of conflict of routes at the track layout.

Optional routes-The route establishing means is effective automatically to select a predetermined one of alternative or optional routes extending between an entrance and an exit point as being preferred, the other route, or the other routes, being automatically established only in the event that the preferred route is not available for use, or has been rendered unavailable as far as the circuits are concerned because of the establishment of a circuit conflict by the 'manipulation of the auxiliary switch control levers. Such mode of operation is effected in accordance with multiple contact selections in the circuits for each of the switch position selecting relays. That is, by the multiple control selections it is provided that certain relays which preselect, responsive to entrance designation, the normal position of a track switch, overrule, so to speak, relays which preselect, responsive to entrance designation, the reverse position of that track switch; and similarly, the relays for preselecting responsive to entrance designation the reverse position of a track switch can be made to overrule relays which preselect, responsive to entrance designation, the normal position of that track switch.

If such multiple circuit selections for the switch position selecting relays are provided, as first described above, so as to give preference to the normal position of each of the track switches that can be trailed in either position in an available route extending from a designated entrance point, the optional route which is then available for use divergingnearest the designated entrance point is given the preference and is selected to be established.

However, if the circuit selections for the switch position selecting relays are provided, as second described above, so as to give the preference to the reverse positions of the track switches of a particular crossover which is not included in the first diverging route from a designated entrance point, the route including such crossover will be given preference, irrespective of the availability of other optional routes diverging nearer such entrance point.

It is believed to be apparent from the general description as it has been set forth that the two conditions described above are directional in that vided independent of the type of preference provided for the opposite direction of traffic.

Thus, to illustrate how either form of preference can'be used, the first described form is provided (see Figs. 1A and 1B) for west bound traffic, and thesecond described form is provided for east bound traffic. With reference to Fig. 1A it is therefore provided that the route from l3 to II] is preferred via crossover 4 (illustrating first described preference), and'that the route from [0 to I3 is preferred via crossover 4 (illustrating second described preference). It is to be understood, however, that either type of preference can as well be provided for both directions of traffic in accordance with the requirements of practice.

The picking up of relay I'3NR responsive to such entrance designation causes the picking up of relay 4130 for the lower end of crossover 4, and the picking up of that relay causes energy to feed through branches or portions of the circuit network corresponding to the track portions including the respective normal and the reverse positions of the track switches of crossover 4, the feeding of energy through the track portion corresponding to the reverse position of the track switches of that crossover being effective to cause the energization of relay ZAN for the upper end of crossover 2. When relay ZAN is picked up, the exit relay IOXR is conditioned for energization so that it can be picked up upon designation of an exit point at H]. Energy feeding through the branch of the circuit network corresponding to the lower one of the two main tracks causes the picking up of the relay 3AN for the single track switch 3. When relay 3AN is picked up, energy feeds further through the circuit network to cause the picking up of relay 2B0.

Inasmuch as the relay IUXR has been conditioned for energization by energy feeding through the circuit network upon the picking up of relay ZAN, the depression of the button IBXB for designation of the exit point at H] in the setting up of the route causes the picking up of the exit relay IUXR, and the picking up of that relay applies energy at a feed point for the other circuit network which causes the picking up of relayZAC for the upper end of crossover 2. The picking up of relay ZAC causes energy to feed on through the portion of the circuit network corresponding to the upper main track to cause the picking up of the relay 4A0 for the upper end of crossover 4, which relay in picking up completes the selection of the route extending from I 3 to [0 via crossover 4. The positioning of the track switches of crossover 2 is effected upon the picking up of relay ZAC and is dependent upon the joint energization of relays 2A0 and 2AN, while the positioning of the track switches of crossover 4 is rendered effective upon the picking up of relay 4A0, dependent upon the joint energization of relays 4A0 and 4130 at a time when relays 4AN and 4BN are dropped away.

The circuit selections are so provided in the selection of the route just described, that if the relay 230 should be allowed to pick up prior to the picking up of relay ZAN, the relay ZAN would be allowed to be picked up also, and the subsequent completion of the selection of the route responsive to the picking up of the exit relay IDXR would cause the dropping away of the relay ZBC upon the picking up of relay '4AC.

To consider the circuits by which such mode of operation is provided, assume that an operator has just designated the entrance point at I3 by the depression of the button I3NB at a time when the route is available from I3 to Hi via cross-over 4. The depression of that button effects the picking up 'of relay IBNR (see Fig. 1B) in a manner similar to that described with reference to the relay IINR, and the picking up of that relay causes the energization of relay of relay I3NR, backcontact 53'of relay IBXR,

front contact 54 of relay 4BC, back'contact 55 of relay 4AC, wire 55, back contact 51 of relay 3AC, and lower winding of relay 3AN, to (n). Upon'the picking up of relay '3AN a circuit is closed to cause the picking up of relay ZBC 6X- tending from including front contact 52 of relay'lsNR, back contact 53 of relay I3XR, front contact 54 of relay 4B0, back, contact 55 of relay 4AC, wire 56, back contact 51 of relay 3AC, front contact 51 of relay 3AN, and lower winding of relay 2B0, to

The picking up of relay 4B0 also causes energy to flow through a portion of the circuit network corresponding to the route extending over crossover 4 to cause the picking up of, relay 2AN by the energization of a'circuit closed from including front contact '52 of relay l3NR,'back contact 53 of relay I3XR, front contact 54 of relay 430, back contact 58 of relay 4BN,-back contact 59 of relay 4AN, Wire 60, back contact 6| of relay ZAC, and lower winding of relay 2AN, to The picking up of relay ,2AN closes a stick circuit for that relay at front contact 62 to shunt back contact 6! out of'thecircuit just described. I

7 Upon the designation of the exit point a tl by the depression of the button IUXB, the relay IOXR is picked up by the energization of a circuit closed from including front contact 52 of relay I3NR, back contact 53 of relay IEXR, front contact 543 of relay 413C, back contact '58 of relay 4BN, back contact 59 of relay '4AN,

wire 60, front contact 62' of relay 2AN, front contact 63 of relay 2AN, winding of relay lGXR, back contact 64 of relay IONR, and contact 65 ,of button IUXB closed in a depressed position,

per main track to effect the energization of' relay GAG, from including front contact 51 of relay lOXR, front contact 68 of relay 2A0, front contact 69 of relay 2AN, wire 16, and lower winding of relay 4AC, to The picking up of relay 4A0 opens the circuits which have been described for relays 3AN and 2130 at back contact 55 to effect therelease of such relays as those relays are no longer included in a branch of the circuit network corresponding to an avail able route extending from l3. The route isnow completely established from l3 to I via crossover 4, thus rendering the route from 13 to Hi via crossover 2 or from l3 to H unavailable because of the reverse position selected for the track switches of crossover 4.

' For the purpose of illustrating howthe route canbe established from [3 to H1 via crossover 2 when such route is available, and when the route The picking up of relay 4B0 closes a a between those points via jcrossover 4 is unavail able, it will be assumed that such route via crossover 4 is rendered unavailable because of the presence of an east bound train in the detector track section of the upper" end of that track switch, the upper end of the crossover 2 having had its locking released because of the effectiveness of rear release route locking which will be hereinafter considered more in detail. The route looking for track section 4T is, effective to maintain .the relays 4A0 and 4AN energized to correspond with the normal position in which the track switches of crossover 4 are locked.

Under the above assumed conditions, the designation of an entrance point at 53 by the depression of button I3NB causes the picking up of ,relay I3NR, and the picking up of that relay causes the picking up of relay 4BC by the energization of a circuit which has been described. When relay 4BC is picked up, energy, can feed through the branch of the circuit network cor-' responding to the lower one of'the main tracks in the track layout because relay 4AN is picked upat that time to close front contact H. Thus, responsive to the picking up of relay 4BC, the relays 3AN and 230 are successively energized, and the picking up of relay 2B0 conditions the exit relay WXR. for energization so that the sub sequent depression of the exit button "DEB for the designation of the exit point at H) causes the picking up of relay IIIXR by the energization of a circuit closed from including front contact 52 of relay ISNR, back contact 53of relay 13KB, front contact 54 of relay 430, front contact 1| of relay 4AN, wire 56, back contact" 51 of relay 3AC, front contact 5| of relay BAN, front contact 12 of relay 230, back contact 13 of relay ZBN, back contact 63 of relay 2AN, Winding of relay MXR, back contact 64 of relay vIIBNR, and contact 65 of button IOXB closed in a depressed position, to The picking up of relay IUXR, closes a stick circuit at front contact '66 to shuntvcontacts 64 and 65 out of the circuit just described.

Responsive to the picking up of relay l0XR,jin the establishment of a route from 3 to H] via crossover 2, the relay 2A0 is picked up in a manner which has been described, and the picking up of that relay causes-the energization of relay 3A0 by closing a circuit for that relay extending from including front contact 61 of relay IUXR, front contact 68 of relay ZAC, back contact 69 of relay 2AN, back contact 31 of relay 2BN, and lower winding of relay 3A0; to ()L It will be noted that the picking up ofrelay 2A0 responsive to the energization of relay IOXR causes energy to feed through the circuit portion of the network corresponding to the crossover 2 because relay 2AN has not been energized responsive to entrance designation and therefore closes back contact 69. The picking up of relay 3AC causes the picking up of relay 4BN by the energization of a circuit closed from including front contact 61 of relay lOXR, front contact 68 of relay 2A0, back contact 69 of relay 2AN, back contact 31 of relay ZBN, front contact 38 of relay 3AC, back contact 4| of relay 3B0, wire 42, front contact 14 of relay '4AN, and lower winding of relay 4BN; to ()z The track switches of crossover 2 are operated to their reverse positions in accordance with the establishment of theroute because of the joint energization of relaysIZAC and 236 with relays ZAN and 2BN deenergized." The single track switch 3 is operated to its normal position in accordance with the joint energization of relays 3A0 and 3AN. The track switches of crossover 4 are maintained in their normal positions in accordance with the joint energization of relays 4BN and 430.

It is believed to be readily apparent from the specific description as heretofore set forth how the system provided by the present invention can be applied to track layouts having a series of optional routes to provide preference for the available route diverging nearest the entrance point involved, such preference being effective for that direction of traflic irrespective of the type of optional route preference provided for the opposite direction of traflic.

It is to be understood that the same type of preference as described for west bound traflic could have been provided in Figs. 1A and 1B for east bound trafiic in a similar manner to the arrangement of the circuits which have been described. Such an arrangement is illustrated, for example, in the circuits shown in Fig, 6A and 63 by which it is provided that the preferred route for each direction of traflic is the one which diverges nearest the designated entrance point.

To consider a typical example of how the circuits can be arranged to provide a preference for selecting the optional route diverging remote from the designated entrance point, with reference to Figs. 1A and 1B, assume under normal conditions that an operator desires to establish a route for east bound traffic from I ll to l3. The designation of the entrance point for such route by the depression of button IUNB causes the picking up of the entrance relay IBNR, and the picking up of that relay causes the picking up of relay 2A0 in the circuit network which is energized responsive to entrance or exit designation for the route ends at the left hand end of the interlocked group. The picking up of relay 2AC causes energy to feed in the circuit network through the circuit portion corresponding to the route including the track switch at the upper end of the crossover 2 in a normal position, and also to feed through the circuit portion corresponding to the establishment of a route including the track switches of the crossover 2 in reverse positions. Energy feeding through the branch corresponding to the normal position of the track switches of crossover 2 causes the picking up of relay 4AC for the upper end of crossover 4, and energy feeding through the other branch of the circuit network causes the picking up of relay 3A0 for the single track switch 3. Responsive to the picking up of relay SAC, energy feeds on in the circuit network through a circuit portion comparable to the portion of the track layout including track switch 3 in a normal position, and also through the circuit portion corresponding to the track switch 3 in a reverse position. The feeding of energy through the circuit portion of the network corresponding to the lower main track cannot be effective, however, to cause the picking up of relay 4BN for the lower end of crossover 4 because the circuit for that relay is opened by the relay 4A0 which is picked up at that time. If relay 4A0 has not yet had time to be picked up, because, for example, of such relay being slightly slow in acting as compared to the other relays used in the system, the momentary energization of relay 4BN with back contact 43 of relay 4AC closed may cause the relay 4BN to be momentarily picked up, but the picking up of relay 4AC will be effective to cause the release of that relay. This particular type of a circuit interlock by which the relay 4AC causes the dropping away or prevents the energization of relay 4BN is the means provided by which the route extending from I0 to 13 via crossover 4 is selected in preference to the route via crossover 2. This is true because the picking up of relay 4BN definitely determines that the track switches of crossover 4 should be operated to normal positions if a route is completely established from H! to I 3.

To consider the circuits in detail for providing the establishment of a route from I 0 to I 3 via crossover 4, assume that an operator depresses the entrance button IONB at a time when either of the routes extending between H] and I3 is available. The picking up of relay IUNR, responsive to such entrance designation, causes the picking up of relay 2A0 by the energization of a circuit closed from including front contact 88 of relay IONB, back contact 61 of relay HJXR, and lower winding of relay 2AC, to Upon the picking up of relay 2A0 a circuit is closed to cause the picking up of relay 4AC extendin from including front contact of relay IUNR, back contact 61 of relay IOXR, front contact 68 of relay 2A0, back contact Bl of relay ZBC, wire 10, and lower winding of relay 4AC, to The picking up of relay 4A0 causes energy to feed through the network to condition the relays I 3XR and IZXR for energization.

When relay 2A0 is picked up, energy feeds through the portion of the circuit network corresponding to the crossover 2 and causes the picking up of relay SAC for the single track switch 3 by the energization of a circuit closed from including front contact 88 of relay IDNR, back contact 51 of relay IBXR, front contacts 68 of relay 2A0, back contact 69 of relay ZAN, back contact 31 of relay ZBN, and lower winding of relay 3AC, to The picking up of relay 3A0 causes energy to flow through the portion of the circuit network corresponding to the route including track switch 3 in a reverse position to condition the relay MXR for energization, and energy also feeds through the branch comparable to track switch 3 in a normal position to back contact 43 which is open at that time in the circuit for relay 4BN.

Upon designation of the exit point at l3 by the depression of button I3XB, the relay |3XR is picked up by the energizationof a circuit closed from including front contact 80 of relay IDNR, back contact 61 of relay IOXR, front contact 68 of relay 2A0, back contact 8| of relay 2B0, wire 18, front contact 82 of relay 4A0, back ing of relay 2AN, to

contact 83 of relay 4AN, back contact 84 of relay 4BN, winding of relay ISXR, back contact 85 of relay I3NR, and contact 86 of button I3XB closed in a depressed position, to The picking up of relay I3XR closes a stick circuit at front contact 8'! to shunt contacts 85 and 86 out of the circuit just described.

Responsive to the picking up of relay IBXR, the relay 4130 is picked up upon the closing of an obvious circuit at front contact 53, and the picking up of that relay closes a circuit for the energization of relay ZAN extending from including front contact 53 of relay IBXR, front contact 54 of relay 4B0, back contact 58 of relay 4BN, back contact 59 of relay 4AN, wire 68, back contact 88 of relay ZBC, and lower wind- The track switches of crossover 4 are operated to their reverse positions in accordance with the joint energization of relays 4AC and 4130 with relays 4AN and #BN dropped away in a manner hereinafter described, and the joint energization of the relays 2A0 and ZAN cause the normal operation of the track switches of crossover, 2 to complete the establishment of the route from H! to 13 via crossover 4.

If'for some reason the track switches of the crossover 4 cannot be operated to their reverse positions, because, for example, of thepresence of an east bound train in the detector track section for the upper :end of that crossover, when there "is a route available extending from ID to 13 via crossover '2, because of release locking having become eifective for that crossover, such route can be established responsive to entrance and exit designations in a manner about to be described.

The designation" of an entrance point at 10 under such conditions causesthe picking up of relay I-GNR, and the picking up of that relay causes the picking up of relay 2AC in a manner which has been described. Upon the picking up of relay 2AC a circuit which has been described is closed for relay 3A0, and the picking up of relay 3A0 causes the picking up of relay '4BN bythe energization of a circuit closed'from extendingfrom front contact 86 of relay ItNR, back contact 6! of relay HIXR, front contact 68 of relay ZAC, back contact 69 of relay ZAN, back contact 3! of relay ZBN, front contact 38 of relay 3AC, back contact 41 of relay 3B0, wire 42, front contact 14 of relay 4AN, (that relay being maintained energized because of the presence of a train in the detector track section), and lower winding 'ofrelay ABN, to The picking up ofrrelay 4BN conditions the exit relay -l3XEt-so that the depression of button 13KB causes the picking up of'that relay by the energization of a circuit closed from including frontcontact 80 of relay HJNR, back contact-61 of relay --l-tX'R, front contact 88 of relay 2AC, back contact -69 of relay 2AN, back contact '31 of relay ZBN, front contact 38 of relay 3A0, back contact 4| of relay 333C, wire "42, front con tact 14 of relay -4AN, front contact 84 of relay 4-BN, winding of relay ltXR, back contact '85 of relay 'lBNR, and contact 85 of button I3XB closed in a'depressed position, The picking up of relay I3XR, due to the energization of that circuit, closes a stick circuit at front contacts! to shunt contacts 85 and 86 out of the circuit just described.

Responsivefito the picking up of relay I'SXR, energy is applied to an obvious circuit for relay 4136 at front contact '53, and the picking up of that relay causes the picking up of relay 3AN by the ''energization of a circuit extending from including front contact 53 of relay ISXR, front contact .54 ofrelay -4BC, front contact 58 of :relayABN, wire 55, back contact 89 of relay 3BC,'aand lower winding of relay SAN, to When relay 3AN is picked up, a circuit is closed to cause the picking up of relay 2B0 to, completeth'e selection of the route, extending from including front contact 53 of relay I3XR, front contact 54 of relay4BC, front contact '58 of relay '4BN, wire 55, back contact 89 of relay BBC, front contact -51 of relay 3AN, and lower winding of relay 23C, to switches. of crossover '2 are operated "to their reverse positions in accordance with the joint :energization of relays 2A0 and ZBC with relays JAN and ZBN :deenergized, and the track switch The track 3 is operated to its normal position in accordance with the joint energization of relays EBAC and SAN. The track switches of crossover 4 remain locked in their normal positions in accordance with the energized condition of the relays ABC and 4BN, which are energized in accordance with the normal position of the track switches of crossover 4 to maintain the route established after the east bound'train assumed to be on the upper main track has left the detector track section for the upper end of crossover d. The picking up of relay 413C in the establishment of the route closes a multiple path in the stickcircuit for relay i-3XR which includes front contact of relay 4BN connected in series with front contact 9| to provide a multiple path aroundfront contact 14 in the stick circuit for relay 13KB, thus providing that the restoration of the relay-AAN in accordance with the passing of the train on the upper track will not effect the deenergization of the relay I3XR.

Switch controZ;-In order that the operation of each of the track switches when setting up a route shall be effected only when its operation is required for that route, it is provided that the operation of that track switch to a normal or reverse'position is effected only after it has been definitely selected that such track switch must be positioned in the route being established by the joint energization of two switch position selecting relays, one of which being energized responsive to entrance or exit designation for a route end at one end of the interlocked group, and the other being responsive to entrance or exit designation for the opposite end of the interlocked group. The combination of relays energized determines to what position the track switches shall be operated. For example, for crossover 2 it is provided that the positioning of the track switches for that crossover will be effective only under conditions where the switch position selecting relays for that crossover are energized in one of the combinations in the following table:

Switch execution table Relays Function 2 normal in route i,

2 reverse in route 2 normal by auxiliary control 2 reverse by suxiliary control 3 normal in route 3 reverse in route Up 3 normal by auxiliary control. Up. 'Up 3 reverse byauxiliary control- Up To consider as a typical examp e how the track switches'of a crossover are operated to their reverse positions responsive to the selection of such positions in the stablishment of a route, assume that a route is established extending over the crossover 2 in a manner which has been described responsive to entrance and exit designation, such as is the case in establishing a route as described