US2315864A - Railway traffic controlling apparatus - Google Patents

Description

April 6, 1943.

L. v. LEWIS RAILWAY TRAFFIC CONTROLLING APPARATUS 7 Sheets-Sheet 1 Filed Dec. 6, 1941 92 1AM? 719 9 Z ZWK J22 H125 [mam r012 Q Lloyd Klewllr.

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Patented Apr. 6, 1943 RAILWAY TRAFFIC CONTRGLLING APPARATUS Lloyd V. Lewis, Pittsburgh, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pin, a corporation of Pennsylvania Application December 6, 1941, Serial No. 421,865

27 Claims.

My invention relates to railway trafiic controlling apparatus, and more particularly, to an interlocking control system for governing the movement of trafiic through a track layout comprising a plurality of track sections interconnected by track switches which may be variously arranged to form difierent traific routes.

The system of my invention is of the entranceexit route interlocking type in which the switches and signals for the different traffic routes are governed by the operation of push buttons mounted on a suitable control panel which also includes an illuminated diagram of the track layout. A push button is provided for each route end in the track layout, and the track switches are operated as required to establish a desired route in response to the successive momentary operation of the two push buttons identified with the opposite ends of the route, the signal at'the entrance end clearing automatically as soon as the route becomes established.

My invention is an improvement upon that disclosed in my prior application for Letters Patent of the United States, Serial No. 252,803, filed January 25, 1939, for Railway trafiic controlling apparatus, and also upon that disclosed in an application for Letters Patent of the United States, Serial No. 310,798, filed December 23, 1939, by Henry S. Young, for Railway traffic controlling apparatus.

One object of my invention is the provision of an improved arrangement of route selecting circuits requiring fewer route relays and a smaller number of contacts per relay than have been required heretofore in systems of corresponding scope.

A feature of my invention is the provision of improved and relatively simple arrangements for selection between alternative routes having the same route ends, and for the provision of through routing in the case of routes involving intermediate signals.

Another object of my invention is the provision of an improved control panel in which the route buttons and miniature levers for operating the track switches individually may be mounted in a row below the track diagram to secure a more compact arrangement, and in an improved arrangement for lighting the lamps of the track diagram. Other objects and features of my invention will be pointed out as the description proceeds.

I shall describe one form of my invention and shall then point out the novel features thereof in claims.

Referring to the accompanying drawings, Figs. 1A, 1B and 1C taken together show the track plan for a typical layout chosen to illustrate the route interlocking system of my invention, together with the circuits for the entrance relays and route relays associated with the operators control panel and controlled directly by the operator in establishing the various routes. Fig. 2 shows the circuits for signal control relays for controlling the signals. Fig. 3 shows the usual signal indication lamps on the track diagram.

Fig. 10 shows the operators control panel including an illuminated track-diagram corresponding to the track layout and indicates the preferred location of the route buttons for controlling the circuits of Figs. 1A to 1G and of miniature switch levers L for operating the track switches individually. Fig. ll shows the circuits for the indication lamps in the tracks of the diagram of Fig. 10.

Referring to Figs. 1A, 1B and 1C, the track layout shown is similar to that of my prior application hereinbefore referred to, and comprises the two main tracks of a double track railroad connected by three crossovers comprising the pairs of track switches IA and IB, 5A and 5B, and IA and IB, respectively, the lower track being also connected to a siding by single switch 3. All of the track switches are in their normal positions as shown. Train movements over the various trafiic routes through the layout are governed by .the signals 2, 4, 6, 8, I0 and I2, which signals are normally at stop, as shown. Signals I and I l) are two-arm signals each having a main arm such as 4A or IDA for governing high speed train movements over the main track in the normal direction, providing the track portion extending to the next signal in advance for the same direction, such as signal 23 or 28, is unoccupied, and also having a slow speed arm such as 4C or IflC which governs train movements over diverging routes and in addition serves as a call on signal which may be cleared to admit a train to an occupied main line route. Signals 2, 6, 8 and I2 are slow speed signals which may be cleared provided a proper route is set up but regardless of its occupancy. Signals 2| and 22 are distant signals for signals 4A and IllA, respectively. Signals 20 to 23, inclusive, are automatic block signals of the usual type and their control circuits have consequently not been shown herein.

The track rails are divided into track sections by the usual insulated joints, the upper track including the detector sections IA and 5A, the approach sections HT and MT and the advance section IB'I'. The lower track includes the detector sections AIT, 3T and IT, the approach sections IBT and 2IT and the advance section 4T. Each track section is provided with the usual track circuit having a track battery as shown, at one end and a track relay TR at the other end, connected across the track rails. Each detector section track relay controls a slow pick-up slow release repeating relay TP, while each pair of approach section track relays controls an approach relay, such as relay 4AR or IUAR.

It will be noted that each relay shown herein is identified by a letter or combination of letters prefixed by the designation of the switch or signal with which the relay is associated, and that the circuits are arranged in the written circuit form with similar circuits grouped together in the same view. The contacts are identified by number, and above each contact may be found the designation of the relay which operates it. The terminals of the usual local source of current for energizing the relays are designated B and C, referring to the positive or supply terminal and to the negative or common return terminal, respectively.

Each track switch of Figs. 1A to 1C is arranged to be actuated by a power operated switch machine SM, which may be of the electric motor type, as in the system of my prior application, but preferably, and as shown herein, is of the electropneumatic type, such as is illustrated in the Coleman Patents Nos. 1,238,888 and 1,238,889, issued September 4, 1911, for Railway traffic controlling apparatus. The normal and reverse control magnets and the lock magets for the switch machines IA-SM and IB-SM are shown herein in Fig. 6, where they are identified by the reference characters N, R and L, respectively, these being controlled in the usual manner by a polarized switch control relay IWR. Relay IWR is arranged as in the Young application hereinbefore referred to, so as to be normally deenergized, becoming energized either in response to the operation of the route selecting relays for routs over crossover I or in response to the operation of the switch lever IL provided for operating crossover I individually. Relay IWR is held energized by an associated locking relay ILR as long as the route remains set up, and also until a train which has entered the route has passed over the track switch controlled thereby and has vacated the detector track section.

The switch machines SM control polarized switch indication relays WP as in the above-mentioned Patent No. 1,238,889, and each relay WP controls correspondence relays NC and RC, relay NC or RC being energized only when the associated relay WP indicates that the switches are locked in their normal or reverse position, respectively, to correspond with the last operated position of the control relay WR. Relays WP and WR also control switch indication relays NWK RC, but are normally deenergized, one or the other being energized only when the associated switch control relay WR is picked up.

It is to be understood that the control and indication circuits for the remaining switches are similar to those shown in detail for switches IA and IB, except that in case of the single switch 3 only one switch machine is required.

Referring now to the route selecting apparatus of Figs. 1A to 1C, a push button P is provided for each signal location or route end, and the track switches may be operated as required to establish any route by momentarily operating the two push buttons identified with the opposite ends of the route, as in the Pelikan Patent No. 2,244,401, granted June 3, 1941, for Railway traflic controlling apparatus, and likewise, as in that patent, the relative order of operation of the two buttons determines the trafiic direction, the button operated first functioning as an entrance button, the signal at the corresponding entrance end of the selected route clearing automatically as soon as the route becomes established. The relays involved include an entrance stick relay PS for each button which is picked up in response to the momentary operation of the associated button provided the entrance relays for conflicting or opposing routes are in their released positions and also include one normal and one reverse route relay for each track switch, such as the relays IANE and IRE for switch IA, or the relays IBNW and IRW for switch IB. The arrangement differs from those employed heretofore in systems of this character in that a pair of route relays is provided for each switch, regardless of whether it is operated singly, like switch 3, or is included in a crossover, like switches IA and IB.

The route relays are controlled by the entrance relays and route buttons over a novel circuit net,- work of interconnected circuits arranged like the tracks of the layout to include a two-wire route circuit for each route. Each route circuit constitutes a loop extending from a connection to the supply terminal B of a local source of current at a front contact of the entrance relay for the selectedentrance end of the route to a point cortresponding to the exit end and thence back to the entrance end, over which the route relays (one for each switch of the route) are energized in parallel, the relays E being energized over the upper wire, and the relays W over the lower wire of the two-wire circuit. The circuits associated with the route button 8P for the intermediate signal 8 are somewhat differently arranged and include interlocked directional relays for sectionalizing the circuits at that point, these including the exit relays BXR and 8X8, used only in setting up routes governin tramc from left to right, and the relay 5ANW, used only in setting up routes from right to left. A relay 8PR is also provided which serves in place of button 8P to effect through routing.

The route circuits are selected in part by the operation of the route relays, and the novel mode of operation may be more readily understood by considering the effect of operating a particular button, such as button E, but without tracing the circuits in detail. If this is the first button operated, relay 4P8 will pick up, marking point 4 as the entrance point, and energizing a portion of the route circuit for route 4-8 to pick up the route relays IRE, SXR and BANE, also energizing a portion of the route circuit for route 4I2 to pick up relays 3NE and 'FBNE. The points 8 and and RWK which are repeaters of relays NC and I2 are thereby rendered available as alternative exits to be selected by the operation of button SP or IZP, this being indicated by the lighting of the corresponding exit lamps on the track diagram. The energized route relays isolate these route circuits from those for routes having diiierent entrance points such as 2 or 6, and also render the entrance relays controlled by buttons 8P, 1UP and HP non-responsive. If the operation of button IZP follows that of button 4P, for example, it serves merely to connect the two wires of the circuit for route 4-l2 together at their exit end to pick up the remaining route relays .iBNW and IBNW for that route, a front contact of relay SBNW maintaining the connection after button HP is released, these relays also isolate the circuit for route 4|2 from those having different exit points, thereby releasing the relays for route 48. The route relays, energized in parallel over a front contact of the entrance relay 4P8, then include one for each switch of route 4-! 2, and relay 4PS is held energized in turn over a front contact of the track relay for the first track section AIT of the route until a train enters the route, or until button 4P is pulled to cancel the route manually.

The energized route relays efiect the establishment of the selected route by governing the switch control relays WR of Fig. 6 in a novel manner, each switch being operated as soon as the required position is ascertained. For example, butthat the switch control relay IWR is energized 5 normal by relay IANE which picks up in response to the operation of the entrance button 2P, but when button 4P is operated, the required position of crossover I is indeterminate and the energization of relay iWR is not effected until the selected exit button 8? or 52! is operated. In this manner the number of switches to be operated simultaneously is reduced. decreasing the maximum demand upon the power source and speeding up operation.

When each track switch assumes the required position, the corresponding indication relay NWK or RWK becomes energized, as alread mentioned, and these relays also serve to isolate the energized route circuit from those for conflicting routes, being eiTect-ive after a train has entered the route and the route relays consequently are released, to restore the route circuits to normal, section by section. as the successive sections are vacated by the train.

The indication relays NWK and RWK also serve to complete a circuit for the control relay HR for the signal at the entrance end of the route, as soon as it is fully established.

The circuits for the relays HR. are shown in Fig. 2. Heretofore it has been the practice to include contacts of the route relays in circuits of this character in order to require the operation of both the entrance and exit buttons to reestablish a route already occupied by a train. This result is attained without the use of additional contacts as required heretofore. by energizing the circuits of Fig. 2 over terminals IE to i8, inclusive, which extend to correspondingly numbered terminals of at least one route relay controlled by the exit button has been picked up.

Each signal control relay HR, together with the correspondence relays NC and RC of Fig. 6, prepares a circuit for clearing the corresponding signal, as shown in Fig. 7, but the clearing of the signal is made dependent upon the locking electrically of each switch of the route in the required position in response to the operation of relay HR. The signals, as shown herein, are to be understood to be of the well-known searchlight type, each having a mechanism G, such as that of the E. J. Blake Reissue Patent No. 14,940 of August 31, 1920. The mechanisms G for each interlocked signal, shown in 7. controls the usual back-lock indication relay RGP as shown in Fig. 4 or 5, which is energized when the signal indicates stop. The mechanisms for the distant signals 2! and 22 control the indication relays 2i RH'GP and 22 RGP which energized when the respective signals indicate either stop or caution.

An approach locking relay AS is provided for each signal, which is normally energized by the associated indication relay RGP when the signal is at stop and is released upon the energization of the associated relay HR prior to the clearing of the signal. Two types of approach locking relay circuit are provided; Fig. 4 shows circuits typical of those used with slow speed signals such as signals 2, 6, 8 and I2, and provide for the energization of relay AS at the end of a relatively short time interval after the signal is manually put to stop, measured by the heating period of the thermal relay TE. Fig. 5 shows circuits used with the high speed signals 4 and Ill where a longer time interval is required, in which case relay TE picks up an auxiliary stick relay TES at the end of its heating period, and relay AS picks up at the end of the subsequent cooling period. These circuits are arranged as in the Vantassel Patent No. 2,198,712, issued April 30. 1940, so as to insure that relay TE is in its normal condition at the beginning of the measured time interval.

It is also to be noted that the circuits of Fig. 5 are so arranged that the approach locking relay is held energized when the home signals which control it are at stop, regardless of the condition of the distant signal, but can be picked up only when the distant signal displays a restrictive indication. This arrangement is claimed in a copending application for Letters Patent oi the United States, Serial No. 417,892, filed November 51941 by R. A. McCann, for Railway trafiic controlling apparatus.

Each approach locking relay AS functions in such a manner that it must be released to'per-'" mit the clearing of the associated signal and must be picked up to permit the operation of any switch in a route which such governs. Each relay AS, when released. connects the associated signal mechanism to the signal net 0 work circuit of Fig. 7 and also releases a series of section locking relays ES or WS, shown in Fig.

4, including one for each track section. of the selected route, in accordance with the usual practice, and the section locking relays then release the switch'locking relays LR of Fig.6. The relays LR upon releasing, complete hold ng circuits for the associated switch control relays WR to lock the switches of the route in the required positions, and byclosing their back contacts in Fig. 7, complete the circuit for the mechanism G for the signal at the entrance to the route to cause it to indicate clear.

It will be seen that the apparatus employed in the system of my invention consists largely of relays; these are arranged in two groups. One group includes the relays of Figs. 2 to 5, all the relays of Fig. 6 except the relays NWK and RWK, and also includes the call-on stick relays M308 and IUCOS, the track relays TR and TP, and the approach relays AR of Figs. 1A and 10, all of which are to be understood to be of the standard type generally employed in railway signaling. The second group comprises those relays associated directly with the operators control panel which are preferably of a smaller type, such as that shown in my Patent No. 1,815,947, granted July 28, 1931, for Electrical relays, and are mounted in a cabinet adjacent the control panel of Fig. 10. The relays of this second group include the entrance and route relays of Figs. 1A to 10, the indication relays NWK and RWK of Fig. 6, already referred to, and in addition include the section indication relays SF of Fig. 8, which as shown in Fig. 11, control the circuits for the white lamps of the track diagram.

It will be readily apparent that the control panel employed with the system of my invention'may be of the type shown in my prior application employing a track diagram with linear light units with the route buttons located at the endsof the routes on the track diagram, but an alternative arrangement such as is shown herein in Fig. 10 is preferred, as it provides a more compact arrangement and permits a simplification of the lamp circuits. In Fig. 10 the illuminated indicators K are of relatively small dimensions and are preferably of the telephone lamp type such as is shown in my Patent No. 1,897,668, issued February 14, 1933, for Lamp receptacles. The route buttons P, and likewise the levers L for operating the switches individually, are shown mounted in a row below the diagram. The latter may be of the miniature type such as shown in my Patent No. 1,887,273, issued November 8, 1932, for Circuit controllers.

The lamps of the track diagram are controlled in part by the relays of each of the two groups above mentioned, the circuits therefor being shown in Figs. 9 and 11. For each interlocked signal an indicator GK is provided on the track diagram, comprising normally dark red and green lamps, as shown in Fig. 9. The red signal indication lamp becomes lighted in response to the operation of the associated entrance relay when a route is to be set up, and this lamp is extinguished and the corresponding green lamp is lighted when the signal clears in response to the release of the corresponding indication relay RGP by the signal mechanism, as shown in Fig. 4 or 5. In the case of signal 4A or USA, the signal will of course remain at stop if a controlling track section in advance is occupied. In this case the operator may reoperate the entrance button to pick up relay GCOS or IGCOS, interposing a contact of an interrupter relay CT (Fig. 11) in the lamp circuit to cause the indicator to display a flashing red indication, which changes to a flashing green indication upon the clearing of signal 4C or IOC.

The distant signals 2| and 22 are each provided with an indicator DK comprising a green lamp which is normally dark but which is controlled by the associated relay RHGP of Fig. so as to become lighted when the signal indicates proceed.

The tracks of the diagram include a red lamp TK for each detector section and an approach lamp AK for each approach section lighted by the release of the track repeater relays TP and approach relays AR of Figs. 1A to IC so as to indicate the occupancy of the corresponding sections, and also include a plurality of white lamps controlled over front contacts of the track repeating relays TP which are lighted in different combinations to indicate the routes established in response to the operation of the route relays. These include an exit indicator, such as 8K or I2K, for each exit point, a normal and a reverse indication lamp such as 3NK or BRK for each single switch, two normal and one reverse indication lamps such as IANK, RBNK and IRK for each crossover, together with one or more additional lamps such as 3K optionally included between the indication lamps for widely spaced switches to enable a row of lights to be more readily traced. The operation is such that when an entrance button is operated, the resulting operation of the route relays causes an exit lamp to be lighted to mark each available exit, lamps BK and IZK for example, in case button 4 is operated. All of these except the one for the exit end of the selected route become extinguished when the exit button is operated and the exit lamp for the opposite end of that route then becomes lighted. One switch indication lamp for each switch of the route becomes lighted in response to the operation of the relay NWK or RWK for the switch as soon as the switch assumes the required position. Finally, a relay SP of Fig. 8 for each section of the route is picked up in response to the release of the section locking relays of Fig. 3, and these serve to maintain the lighting of the white lamps for each section of the route until the train enters such section even though the route selector relays are released. The control of the white lamps by relays SP serves further to provide an indication of the release of the approach locking effective when a route is cancelled manually.

The white lamps RK not only indicate that the switches are locked reverse when steadily lighted, but they are also controlled over back contacts of the switch indication relays WP and a contact of an interrupter relay CT so as to display a flashing indication in case a switch becomes unlocked or displaced from its last operated position at any time, or if during operation it remains in transit from one operating position to another for a sufiicient time for the indication to be observed.

I shall now describe the operation of the apparatus of my invention under different assumed conditions, tracing the circuits in detail. I shall first assume that the apparatus is in the normal condition as shown in the drawing and that the operator desires to clear signal 4A to pass an approaching train over route 4l2.

When the train enters the first approach section IQT, Fig. 1A, the track relay ISTR drops and releases the approach relay 4AR, whereupon the approach indicator 4AK becomes lighted on the track diagram to inform the operator of the approach of the train. 1

Normally all of the indication lamps shown in Fig. 10 are dark, and each route button is conditioned to function as an entrance button, as already mentioned.

To set up route 4-l2, the operator will first operate button 4P momentarily to pick up relay 4PS. The pick-up circuit for relay APS may be traced from terminal B at front contact 25 of track relay AITR,'Fig. 1A. contact of button 4P, back contacts I5 and "I6 of relays IRW and IBNW through relay 4PS to terminal C. Relay 4PS picks up and completes its stick circuit which is a branch of the circuit just traced including the normally closed pull contact 2'! of button 4? and front contact 28 of relay 4P8.

Contact 29 of relay 4PS in Fig. 9 completes the circuit for the red lamp of the signal indicator IGK on the track diagram, and contact 30 of relay 4PS in Fig. 1A connects terminal B to the upper wire of the two-wire route circuit for each route originating at the location of signal 4.

It will be seen that the track layout provides two alternative routes 4I0, one via I reversed and the other via 5 reversed. Th former is taken as the preferred route 4-H) in order to free the parallel route 6-I2, and the circuits are so arranged that the secondary route 4-H] via 5 reversed is normally unavailable. Furthermore, the preferred route 4I6 via I reversed includes the intermediate signal 8 and therefore constitutes a through route comprising two routes 4-8 and 8I6 in end-to-end relation, and although my apparatus is adapted to provide through routing for the establishment of such routes by the operation of the two end buttons only, it is considered preferable not to employ that method for setting up routes for train movements against the normal direction of traffic, that is, toward a high signal such as I6, and for this reason, through routing is provided for route 2-I2 only, and is not provided for route 2-H] nor for route 4-46 via I reversed. The track plan shows three routes 4-42, the main line route via I normal and I 7 normal, and the two run-around routes via I reversed and I reversed, and via 5 reversed and I reversed. The main line route 4-I2 is of course the preferred route and is the only one of the three provided for in the circuits. Route 4--I2 via I reversed and I reversed, however, can be established by setting up the partial routes 4-8 and 8I 2 successively. There are, therefore, normally but two available routes originating at point 4; route 4-8, and the main line route 4I 2. The route circuit for rout 4-8 extends from terminal B at contact 36 of relay 4PS over a back contact of relay iBNW from which point one branch extends over back contacts of relays INWK and IANE through relay IRE to terminal C. Relay IRE picks up and extends the route circuit over its front contact 3 I, wire 32, back contacts 33 and 34 of relays 5ANW and 8X8 through relay 8XR to terminal C. Relay SXR picks up and by closing its contact 35, Fig. 11, lights the exit indicator 8K and also energizes relay 5ANE over a branch of the circuit for relay EPS extending from terminal B at contact 36 of relay 5TR, Fig. 10, wire 31, back contacts of relays 5RWK, BANW, SRW and ISP, front contact 38 of relay 8XR, back contact 39 of relay BPS through relay 5ANE to terminal C. Relay 5ANE picks up and by opening its back contacts in the circuits for relays 5RE and ERW prevents button IIJP from functioning as an exit button to complete the route circuit for the secondary route 4I6 via 5 reversed. Relay SANE also opens its back contact I64 in the circuit for relay IOPS to prevent button I 6P from functioning as an entrance button.

The route circuit for the main line route 4I 2 extends from terminal B at front contact 36 of relay 4PS over a back contact of relay IRW from which point a branch extends over back contacts of relays IRWK, 3RWK and SRE through relay 3NE to terminal C. Relay 3NE thus picks up in response to the operation of relay 4PS and extends the circuit for route 4l2 over its front contact 40, wire 4I, back contacts of relays 5RW and 5RWK, wire 42, back contacts of relays 'IRWK and IRE through relay 'IBNE to terminal C. Relay 3NE also opens back contactsin the circuits for routes 6III and 6-l2, thereby. rendering button 6P ineffective. Relay 'IBNE picks up and extends the circuit for route 4I2 from wire M and the back contact of relay 5RW over wire 43, front contact 44 of relay IBNE, back contact 45 of relay IZPS to contact 46 of button I2P. Relay 'IBNE opens its back contact 41 in the pick-up circuit for relay I2PS, thereby conditioning button I2P to function only as an exit button, and closes contact 48, Fig. 11, to light the corresponding exit indicator IZK on the track diagram.

The operator now presses button I2P, extending the circuit for route 4I2 over contact 46 of button I2P, back contacts 49, 50 and 5| of relays IZPS, IRE and 'IRWK, wire 52, back contacts of relays 5RWK and 5RW through relay 5BNW to terminal C. Relay 5BNW picksyup, whereupon button I2P may be released, the energized portion of the circuit for route 4I 2 now extending from back contact 45 of relay IZPS over front contact 53 of relay 5BNW, back contacts 49 and 50 of relays I ZPS and IRE, wire 54, front contact 55 of relay 5BNW, wire 56, back contacts of relays 3RE, 3RWK, I RWK and IRW through r lay IBNW to terminal C. Relay 5BNW opens its back contacts in the circuits for relays 5RE and 5RW, and relay IBNW picks up, opening its back contacts in the circuits for relays IRE and IRW,

whereupon relays IRE, BXR and BANE'release extinguishing the exit indicator 8K. Relay IBNW closes contact 51, Fig, 11, lighting the exit indicator 4K adjacent the entrance end of route 4I2 on the track diagram.

It will be seen that the route relays IBNW, 3NE, 5BNW and IBNE, one for each switch of the route, are now energized in parallel over front contact 30 of the entrance relay IPS, and that back contacts of these route relays isolate the energized route circuit from those for all conflicting routes.

The switch control relays WR of Fig. 6 are energized in the required direction as soon as sufficient route relays have been operated to define the required switch positions, assuming of course that the associated locking relays LR are picked up. It will be noted that all routes terminating at point I2 require crossover 5 to be normal. Accordingly, in Fig. 6 relay 5WR is energized in the normal direction upon the closing of a front contact of relay 5BNW in response to the operation of button I2P either as an entrance or exit button. Buttons 4P and IZP jointly determine the required positions of the remaining switches of the route, and accordingly, relays IWR, SWR and IWR are energized in the normal direction only when two route relays con-. trolled respectively by the entrance and. exit but-' tons are both energized. For example, relays IWR and 3WR in the case being described are energized over front contacts of relays I BNW and 3NE in series, and relay IWR is energized over front contacts of relays 5BNW and IBNE in series, as shown in Fig. 6.

Each relay WR operates the associated switch or switches to normal, if they happen to be reversed or if the associated indication relay WP is deenergized, by energizing the normal magnets N and the lock magnets L of the associated switch The relays NWK also complete circuits for lighting the normal switch indication lamps on the track diagram, the white lamps IBNK, 3NK, SBNK and lBNK becoming lighted in response to the closing of contacts 58 to Gil of relays INWK, SNWK, SNWK and 'lNWK, respectively, as shown in Fig. 11.

As soon as route 4-l2 is fully established so that each relay NWK is energized, the signal control relay AHR of Fig. 2 becomes energized over a circuit extending from terminal B at front contact 30 of relay 4PS, Fig. 1A, over the upper wire of the route circuit for route 4l2 as already traced, that is, over wires 4i and 43 to contact 53 of relay EBNW, Fig. ii), to terminal [8. From terminal is the circuit extends in Fig. 2 over a back contact of relay IZPS and over front contacts of each of the relays NWK and of relay 4P8 through relay 4HR to terminal C.

Relay ll-IR picks up, opening its back contact 62, Fig. 5, to release the associated approach looking relay AAS, which relay is normally held energized over its stick circuit, like the corresponding relay of the V antassel patent hereinbefore referred to.

Referring now to the signal circuit network of Fig. '7, it will be seen that the closing of front contacts 63 and 64 of relay 4BR and of back contact 65 of relay AAS connects the winding of the mechanism GAG for signal 4A to a signal circuit corresponding to route 4l2 which, as may be traced from the drawing, extends to terminal B at front contact 66 of relay IZAS associated with the opposing signal 12, and to terminal C at contact 64 of relay dHR, but which is now open at back contacts I26 to I30 of the relays LR. In Fig. 3, relay GAS opens contact til, releasing the section locking relay AlES for the first section AIT of route 4l2, and relay AIES, in turn, by opening contact 63, releases relay 3E8 for section 3T of the route.

In Fig. 8, relay AIES closes back contact 69, and relay BES closes back contacts and H, thereby causing the section indication relays AISP, 3SP and ISP to pick up, and in Fig. 11, front contacts of the SP relays bridge the closed contacts 48, 51, etc., of the route relays to maintain the white lamps lighted to indicate the route after the route relays release. Lamp 3K is also lighted at this time due to the closing of contact 12 of relay 3SP.

In Fig. 6, relay AIES opens its front contact 13, releasing the switch locking relay ILR, and relay SES opens contacts I24, I25 and I26, thereby releasing relays SLR, SLR and 'ILR, whereupon each relay WR, as shown in detail for relay IWR in Fig. 6, is held energized over its stick circuit including the back contacts of the associated relay LR, and each relay WR holds the corresponding relay NWK energized provided the relays WP and NC remain energized, irrespective of the condition of the associated route relays. The release of the relays LR effects the closing of their back contacts I26 to I39 in the signal circuit of Fig. 7 above mentioned, thereby effecting the energization of mechanism 4AG.

- This circuit, it will be seen, includes front c0ntacts of the track relay for each section between signal 4A and the next signal 23 in advance, and also includes pole changer contacts of a relay 23H? controlled by that signal, so that signal 4A will display caution or clear, depending upon the position of signal 23, but only if the intervening block is unoccupied. It will be understood that the operator may set up the route even though it is already occupied, back contact 14 of the track repeater relay AITP providing a connection to terminal B for energizing relay 4P8 when the first section AIT is occupied, the connection being reestablished over contact 25 of relay AITR as soon as this section is vacated.

In the event the route is set up and signal 4A remains at stop, the operator may clear the callon signal 40 by reoperating the entrance button 4P, as in the system of my prior application, to close the pick-up circuit for the call-on stick relay 4COS. As shown in Fig. 1A, this circuit extends from terminal B at contact 25 of relay AITR or contact 14 of relay AlTP over contact 26 of button 4P, back contact '15 of relay IRW, front contacts 1'6 and H of relays lBNW and dRGP, the winding of relay 4COS, front contact 18 of relay AHR to terminal C.

Relay 4COS picks up and completes its stick circuit at contact 19, and in Fig. 7 relay ACOS completes the energizing circuit for the call-on signal mechanism 40G at its front contact 80.

The operation of the main signal mechanism 4AG to the caution or clear position opens its indication contact Y or G, in Fig. 5. The mechanism 40G, although of similar construction, is are ranged to be energized only in the caution direction to open its contact Y, but in either case, when mechanism tAG or M36: is energized the opening of one of the contacts mentioned relea es the associated back-lock relay 4RGP, and this relay in turn opens contact 8| in the circuit for relay 4AS, thereby insuring that relay 4A8 will remain released 'until conditions are again proper for the operation of the track switches in the route controlled by the signal and the signal has again assumed its stop position.

In Fig. 9, the dropping of contact 82 of relay 4RGP extinguishes the red lamp and lights the green lamp of the signal indication 4GK on the track diagram of Fig. 10. With relay 4008 released, as is the case when the main signal is energized, the green lamp is lighted steadily, but with relay 4COS picked up, a flashing green or red indication is displayed due to the operation of contact 83 of a continuously operating interrupter relay CT shown in Fig. 11.

I shall next assume that the approaching train passes signal 4A or 40 and enters section AIT. If this section is not already occupied by a preceding train, relay AiTR will release and the opening of its contact 25 will release relay 4P8. However, if relay AITR is already released and relay 4P8 is held energized Over back contact 14 of relay AI'I'P, it may be released manually by pulling button 4? momentarily to open contact 21.

Relay EPS upon releasing releases the energized route relays and also relay 4I-IR, but without sparking at any contact due'to the paths pr0- vided for the inductive discharge of the relays through suitable rectifiers as shown. Signal 4A or 4C will be restored to stop allowing relay 4RGP to pick up thereby restoring indicator 4GK to its normal dark position. If the distant signal 2| is properly in its stop or caution position, its contact G will be closed and relay 2 IRHGP will be energized allowing relay 4A8 to pick up over a back contact of the track relay AITR shown in Fig. 5. The slow acting track repeater relay AITP will become deenergized and after a brief time interval will drop its contact 84, in Fig. 11, extinguishing the white lamps 4K and IBNK and lighting the red lamp AITK on the track diagram to indicate the occupancy of the first section of route 4I2. Similarly, the release of relays STP and ITP as the train enters the succeeding sections extinguishes the white lamps and lights the red lamps for these sections to register the progress of the train through the route.

When section AIT is vacated relay AiIR picks up reenergizing relay AIES in Fig. 3, and relay AIES reenergizes relay ILR in Fig. 6, thereby releasing relays IWR and INWK in turn. Relay AIES also releases relay AISP, in Fig. 8, while relay AITR reenergizes the slow pick-up relay AITP which relay is timed to pick up shortly after relay INWK releases, so that when relay AITP picks up the red lamp AITK is extinguished but without completing the circuit for any of the white lamps.

It will be seen, therefore, that the locking of crossover I is released so that a conflicting route such as route 4B involving only section AIT of route 4I2 may be set up as soon as that section is vacated. Similar considerations apply to the remaining sections of the route, the apparatus associated with each of these sections being restored to normal by the passage of the train in a similar manner.

It will next be assumed that the apparatus is in its normal condition and that buttons AP and 8P are operated to set up route 4-8. The operation of button 4P picks up relays 4PS, I RE, SXR and BANE, and relay 5ANE opens its back contacts in the rout circuit for the secondary route 4I0 via 5 reversed as already described. Button SP is conditioned as an exit button by the opening of back contact 85 of relay BXR and the closing of contact 86 when button 8]? is operated picks up relay BXS, which then establishes a stick circuit at its front contact 34, at the same time opening the pick-up circuit for relay 8XR, the latter relay being held energized over a stick circuit including Contact 81 of button 8P until the button is released. Relay BXS closes contact 88 thereby extending the route circuit for route 4-8 over back contact 89 of relay SANW, wire 99, back contact 9| of relay IANE, front contact 92 of relay IRE, back contact I29 of relay IBNW and the lower back contact of relay INWK through relay IRW to terminal C. Relay IRW picks up and opens its back contacts in the route circuit for route 4-I2, releasing relays 3NE and IBNE, and in Fig. 6 relay IRW completes a circuit over a front contact of relay IRE to energize relay iWR in the reverse direction. The crossover I is thereby operated to reverse whereupon relays iWP, I'RC and IRWK pick up, and relay 4HR becomes energized over the connection to terminal it. The remaining operations being similar to those already described in connection with route 4-I 2, further discussion appears unnecessary.

Considering next the routes 28, S-IE! and 8-I2, it will be apparent that if button 2P is operated as an entrance button, relay 2P3 Will be picked up over the circuit extending over wire 93 to terminal B at contact 84 of relay [TR, and then relays IANE, SXR and 5ANE pick up successively. Relay IANE completes the normal circuit for relay IWR in Fig. 6, so that crossover I is operated at once. With relay 8XR picked up,

button HP is conditioned as an exit button, as already described, but there is now another available exit at point i2. Relays ZPS, 8XR and EANE being energized, a branch of the circuit for route 8I2 is closed from terminal 13 at contact 36 of relay ETR as already traced over wire 3! to front contact 38 of relay SXR, and thence over back contact 39 of relay BPS, front contact 95 of relay 5ANE, wire 96, back contact 91 of relay lANW, front contact 98 of relay BPS, back contacts of relays lNWK and TBNE through relay IRE to terminal C. Relay IRE picks up and extends the circuit from contact 91 over its front contact 89 and back contact 45 of relay IZPS to contact 46 of button IZP. Contact I81! of relay IRE opens the circuit for relay IZPS, and in Fig. 11 contact Ilil of relay IRE completes the circuit for lighting the exit indicator i2K.

Assuming now that button 8P is operated, relay BXS picks up extending the circuit for route 2-8 over its contact 88 to terminal It to prepare a circuit for the signal control relay ZHR, thereby completing the selection of route 28. Relays 3XR, EANE and IRE release in response to the release of button 8?. When relay BXR is released, button EP is again conditioned to serve as an entrance button for routes 8-40 and 3-42, and if it is now operated, a circuit is com.- pleted from terminal B at contact 35 of relay 5TB over wire 3?, back contacts of relays ERWK and EANW, contact I02 of button 8P, back contact of relay BXR, through relay 8P5 to terminal Relay BPS picks up to establish the usual stick circuit and connects terminal B at its front contact 39 to the route circuits for routes 8li and 8-Iz2, whereupon relay SANE picks up extending the route circuit for route 8-42 over its front contact 85, wire B5 and front contact sea of relay EPS to pick up relay IRE to thereby condition button. I! as an exit button as already described. Similarly, the opening of back contact Hit of relay iiANE? in the circuit for relay IGPS conditions button IBP as an exit butj ton, its lower contact 585 being connected to terminal B over contacts 39 and and wire it. Relay FANW or l'RW may now be picked up by the operation of the exit button It? or IZP, respectively, to complete the selection of route 8-iil or ii-42, relay Iii-IR becoming energized over the corresponding route circuit terminal I! or I 8 when the route is established.

Considering next the through route 2-I2,'it has already been pbinted out that when the entrance button ZP is operated, relays ZPS, IANE.

EANE and ERE become energized, connecting terminal B to contact at of the exit button I 2?. The operation of button 12? will extend the route circuit over back contact 59 of relay IZPS to pick up relay 'iRW as for route 8-I2, but in the present instance the circuit is further extended over contact it? of relay lRW, wire ace, back contacts of relays 5RE, 5RWK and BPS and front contacts I39 and Ill] of relays 8X3. and 5ANE, through relay SPR to terminal C. Relay GPR picks up and, as will be clear from the drawing, its two lower contacts complete a pick-up circuit for relay 8XS and a stick circuit for relay tXR the same as when button BP is operated, but in the present instance relay 3PR prepares a circuit closed when relay 8X5 picks up to energize relay 8P8, whereupon relays @PR and BXR release due to the opening of the lower back contact of relay 3P8. 'I he relays remaining picked up are relays EPS, IANE and 8X8 for route 2-8, and relays BPS, ANE, IRE and 'IRW for route 8I 2, the same as when these routes are set up separately.

A feature of these circuits is that they are so arranged that the through routing is rendered inoperative when there is a train in section IT approaching signal 8 since under these circumstances it is not desirable to clear signal 8 by the operation of buttons 2P and IZP. This is effected by including a back contact II I of relay ESP in the circuit for relay 5ANE in Fig. 1B, and by controlling relay ESP over a back contact of the track relay ITR. as shown in Fig. 8.

It is believed that the route circuits for routes 6I6 and 6--! 2 which have a connection to terminal B at front contact I I2 of relay BPS require no explanation in view of their similarity to those circuits already traced. The circuits for the secondary route 4-? via- 5 reversed may also-be readily traced, and it will be seen that when relay 4PS picks up a connection to terminal B at its front contact 30 is extended over contact 40 of relay 3NE and wire M and a back contact of relay 5ANE through relay 5RE to terminal C, provided conditions are such that relay SANE does not respond to the operation of button 4P as hereinbefore described, but remains released. If relay SEE picks up, the circuit is extended over its front contact and wire I66 to contact I65 of button IBP, and if button IfiP is operated relay IANW is picked up to further extend the circuit over its front contacts H3 and IE4 and wire I I5 to pick up relay ERW, and from wire i I5 over contact I16 of relay 5RW and wire 56 to pick up relay IBNW. 4I0 via 5 reversed will be established in response to the operation of buttons 4P and IOP, provided relay SANE is prevented from picking up. This will be the case, for example, if route 28 i already set up or if crossover I is locked normal by a train in section IT, in which case relay INWK will be picked up to open the circuit for route 48, or the secondary route may be selected manually. By reference to Fig. 6 it will be seen that each relay WR will become energized in its normal or reverse direction, provided the associated locking relay LR is picked up, by operating the corresponding individual switch lever such as IL to the left or right, respectively from the center position shown. That is, crossover I may be operated to normal to pick up relay INWK, or crossover 5 may be operated to reverse to pick up relay ERWK by means of the individual levers IL and EL, respectively, in which case back contacts of these relays will open the route circuits for the preferred route 4-I0 via 1 reversed and thereby permit the selection of the secondary route 4II via 5 reversed.

In the foregoing I have considered only the establishment of routes for traffic movements from left to right. For trainc movements in the opposite direction the operations are generally similar except that the lower wire of the route circuit is the one that is energized first and for the intermediate signal location relay SANW is operated in place of relays 8XR, 8X8 and BPS. Considering route Iil2, for example, relay IOPS picks up in response to the operation of button IOP as an entrance button, closing a connection to terminal B at its front contact II! to pick up relays IANW and SANW to extend the circuit for route IlI2 to contact II8 of button 2P, the closing of contact I I8 completing the selection of route Ifl-2 by the energization of relays IANE It is clear, therefore, that route and BANE, relay IBHR being energized over the connection to terminal I3. Similarly, for. the main line route I2--4, if relay I2PS is picked up by operating button IZP a connection to terminal B at front contact 49 of relay I2PS provides for the energization of relays SBNW and IBNW, whereupon button 4P may be operated to pick up relays 3NE and IBNE, relay I2HR being energized over the connection to terminal I4.

The circuits for relay I RW in Fig. 1A illustrate the principle of selection employed when there are two alternative routes such a the routes I04 via I reversed and I04 via 5 reversed. If relay IIIPS is picked up to connect terminal B at contact III to the route circuits for both of these routes, relay IRW, associated with the circuit for the preferred route I04 via I reversed, will be picked up over front contact II9 of relay IANW to open the circuit for relay IBNW which otherwise would become energized over the circuit for the secondary route Ill-4 via 5 reversed. Relay IRE will then pick up in response to the operation of the exit button 4P to effect the selection of the preferred route. If, however, for any reason relay IBNW picks up in place of relay IRW, the operation of the exit button 4P will cause relay 3NE to pick up to effect the selection of the secondary route. The back contacts I20 and I2I of relays IBNW and 3NE in parallel in the circuit for relay IRW are both open when the secondary route Iii-4 via 5 reversed has been fully selected and prevent relay lRW from becoming energized to interfere with the circuits for that route. It will be seen that relay IRW may be picked up not only when point I0 is the entrance point and relay IANW is picked up, as above described, but also when point 4 is the entrance point and relay IRE is picked up first to close it contact 92 as required for setting up route 48, and in addition, if the reverse indication relays 'IRWK and IRWK are both picked up to close their contacts I22 and $23. The last-mentioned branch circuit provides a means for manually establishing the run-around route I2 I.

To set up this run-around route I24 via I reversed and I reversed, the operator first moves levers "IL and IL of Fig. 6 to their right-hand positions, whereby crossovers I and I are reversed individually and their indication relays 'IRWK and IRWK picked up. The route button I2P and 4.? are then operated in that order. The open back contacts of the relays 'IRWK and IRWK in the route circuit for the main line route i24 prevent the completion of that circuit, while their front contacts I22 and I23 now closed permit relay IRW to pick up to complete the route circuit for the run-around route.

By reference to Fig. 10 it will be seen that the route circuit in question can be completed only if the lower wire is energized first for the reason that the only available circuit for energizing relay IRE in response to an operation of button 4P is the one including a front contact of relay 'IRW.

In other words, this run-around route circuit is directional and cannot be set up by operating the route buttons I2P and 4P in the reverse order.

The individual switch levers as shown in Fig. 6 are arranged so that they are ineffective unless they are operated at a time when the track switches they control are free to respond. This is accomplished as in the Young Patent No. 2,179,462, issued November 7, 1939, for Railway traffic controlling apparatus. by the provision of a center contact on each lever which, as will be clear from th drawing, must be closed in order to pick up the associated locking relay LR.

Considering next the secondary route [-4 via reversed, it will be seen that this route, like the corresponding one for the opposite direction, may be selected in place of the preferred route Ill-4 via I reversed, by individual switch lever operation, either by operating cross-over l normal to pick up relay INWK or by operating cross-over 5 to reverse to pick up relay ERWK. Furthermore, since these indication relays are controlled by the locking relays and hence by the track relays, this secondary route will be selected automatically in response to the operation of buttons IBP and 4? in case, for example, route 2-8 is occupied or if crossover 5 is reversed and section ST is occupied.

In the foregoing I have described a novel system of route selection involving a route button and associated stick relay for each route end and a single route circuit for each available route extending between the two ends of the track layout over branches of which a route relay for each switch of the route may be energized to thereby establish the route regardless of the order of operation of two route buttons identifying its opposite ends, and in which a signal control relay is energized over another branch of the same route circuit to automatically clear the signal governing traflic movements over the route thus established in one direction or the other, dependent only upon the relative order of operation of the route buttons. I have also pointed out a number of ways in which this arrangement may be varied to suit particular requirements. For example, I have shown how a route may be rendered available only when the route buttons are operated in a particular order, or by positioning one or more of the track switches by individual lever operation prior to the operation of the route buttons, or in the event a preferred alternative route is unavailable. In addition, I have shown how partial routes involving an intermediate signal may be provided for either with or without the operation of an intermediate route button.

Although a relatively simple track layout has been used to illustrate my invention, it is believed that in view of the description of the circuits and operation as presented herein that my invention may be readily applied by one skilled in the art to larger and more complicated track layouts such as are often encountered in practice even though they may differ widely from the layout shown herein.

Although I have herein shown and described only one form of apparatus embodying my invention, it is 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 an interlocking control system, a track layout including track switches adapted to form different traffic routes, a route button for each route end, a normal and a reverse route relay for each track switch, a route circuit network of conductor portions arranged to provide energizing circuits for the route relays and to be connected end to end over front contacts of such route relays to form route circuits, there being one such circuit for each available route through the track layout, each route circuit comprising two conductors extending from contacts associated with the route button for one end to contacts associated with the route button for the other end of the corresponding route so arranged that the route relays for the switches of any route which face in opposite directions are energized over different conductors, means normally responsive to the momentary operation of the route button for the entrance end of a desired route to connect a source of current to one conductor of the route circuit for such route at that end thereby successively energizing one route relay for each trailed switch in such route, means for maintaining said source of current connected to said one conductor until the route is cancelled, means responsive to the subsequent momentary operation of the route button for the exit end of the desired route to extend the connection of said source of current to the other conductor of the same route circuit at that end thereby successively energizing one route relay for each facing switch of said route, means controlled by one of the route relays energized over said other conductor for maintaining the connection between the two conductors of the energized route circuit until said route is cancelled, and means controlled by the energized route relays for operating the track switches to corresponding normal or reverse positions as required for the desired route.

2. In an interlocking control system, a track layout including track switches adapted to form different trafiic routes, a route button having two normally open contacts for each route end, an entrance relay for each route button, a normal and a reverse route relay for each track switch, a route circuit network of conductor portions arranged to provide energizing circuits for the route relays and to be connected end to end over front contacts of such route relays to form route circuits, there being one such circuit for each available route through the track layout, each route circuit comprising two conductors over which the route relays for switches facing in opposite directions may be separately energized, each conductor being connected at each end over back contacts of the entrance relay for the corresponding route end to one normally open contact of the associated route button, means normally effective to energize each entrance relay in response to the operation of the associated route button comprising a circuit including the other normally open contact of said button to thereby disconnect the two conductors of the adjacent route circuit end from said one contact of the operated route button, means comprising a front contact of the energized entrance relay for supplying current to one conductor only of the route circuit connected thereto to successively energize one route relay for each trailed switch of the desired route, thereby extending the connection of said source of current to the one contact of the route button for the exit end of such route, means including a back contact of one of the energized route relays for preventing the energization of the entrance relay associated with the route button for the exit end of the desired route thereby rendering the operation of such button effective to extend the connection of said source of current to the other conductor of the adjacent route circuit end to successively energize one route relay for each facing switch of the .desired route, means including back contacts of the energized route relays for isolating the conductors over which they are controlled for those of conflicting route circuits, and circuits including front contacts of the energized route relays for operating the track switches to corresponding normal or reverse positions as required for the desired route.

3. In an interlocking control system, a track layout including track switches adapted to form different traffic routes, a route button having two normally open contacts and a normally closed contact for each route end, an entrance stick relay for each entrance button, a normal and a reverse route relay for each track switch, a route circuit network of conductor portions arranged to provide energizing circuits for the route relays and to be connected end to end over front contacts of such route relays to form route circuits, there being one such circuit for each available route through the track layout, each route circuit comprising two conductors extending at each end over back contacts of the entrance relay for the corresponding route end to one normally open contact of the associated route button, the route relays for the switches of any route which face in opposite directions being energized over different conductors, a circuit closed in response to the operation of the route button for the entrance end of a desired route if such route is available, including its other normally open contact for picking up the associated entrance stick relay to thereby disconnect the two conductors of the adjacent route circuit end from said one contact of the operated route button, a stick circuit for each entrance stick relay including its own front contact and the normally closed contact of the associated route button, means including a front contact of the energized entrance stick relay for connecting a source of current to one conductor only of the route circuit for the desired route to successively energize one route relay for each trailed switch of the desired route, thereby extending the connection of said source of current to the one contact of the route button for the exit end of such route, means including a back contact of one of the energized route relays for preventing the energization of the entrance stick relay associated with the route button for the exit end of the desired route thereby rendering the operation of such button effective to extend the connection of said source of current to the other conductor of the adjacent route circuit end to successively energize one route relay for each facing switch of the desired route, means including a front contact of one of the route relays energized over said other conductor for maintaining the connection between the two conductors, means including back contacts of the energized route relays for isolating the conductors over which they are controlled from those of conflicting route circuits, and circuits including front contacts of the energized route relays for operating the track switches to corresponding normal or reverse positions as required for the desired route.

4. In an interlocking control system, a track layout including track switches adapted to be interconnected to form different traffic routes, signals at the ends of the routes for governing traffic movements through the track layout in opposite directions, a route button for each signal location, a normal and a reverse route relay for each track switch, energizing circuits for the route relays comprising route circuit portions conforming to the track portions which are adapted to be interconnected over front contacts of the route relays to form route circuits over which the route relays for theswitches of a route may be successively energized, there being one route circuit for each available route through the track layout, each route circuit comprising two conductors over which the route relays for the switches trailed for opposite directions of traffic movement may be separately energized, means including back contacts of the route relays for isolating the route circuits over which they are energized from other route circuits, means normally responsive to the momentary operation of the route button for either end of an available route to connect a source of current to a route circuit conductor terminating at that end to effect the energization of a route relay for each switch which may be trailed by a train entering the layout at the corresponding route end, the energized route relays being effective to isolate the route circuits for these routes from those having different entrance ends at the same end of the layout, means responsive to the momentary operation of the route button for either end of an available route when one conductor of a route circuit terminating at the corresponding point is already connected to a source of current at its opposite end to extend said connection to the other conductor of the same route circuit to effect the energization of one route relay for each remaining switch of the desired route, the route relays thereby energized being effective to isolate the route circuit for that route from those having different exit ends, and means controlled by the energized route relays for operating the track switches to normal or reverse positions as required for the desired route and for clearing the signal at one end or the other of such route when such route is established depending upon the relative order of operation of the route buttons for the opposite ends of such route.

5. In an interlocking control system according to claim 4, in which the routes established by the operation of the route relays are available for trafiic movements in either direction, means for rendering a particular route establishable for traffic movements in one direction only, comprising a connection over which one route relay for a switch of said particular route is energized when current is supplied to one conductor of the route circuit for said route, which includes one or more normally open contacts in multiple one of which is a front contact of a route relay controlled over the other conductor of the route circuit for said particular route, said one front contact being bridged by another contact if the energization of said one route relay is required in order to establish a different route.

6. An interlocking control system for controlling the operation of power operated track switches adapted to form different traffic routes in two directions through a track layout, comprising manually operable entrance and exit contacts for each route end, an entrance stick relay for each route entrance having a pick-up circuit contact at its other end, means comprising back contacts of the route relays for each route for isolating the directional circuits for such route from those for conflicting routes, means responsive to the closing of the entrance contact for the entrance end of an available route for energizing the associated entrance relay, means including a front contact of that entrance relay for supplying current to the entrance end of one directional circuit for such route to thereby energize one route relay for each trailed switch of such route, and to extend the energization of such circuit to its exit end, means responsive to the subsequent closing of the exit contact for the exit end of such route for supplying current from the directional circuit already energized at its exit end to the adjacent entrance end of the other directional circuit for the same route thereby energizing one route relay for each facing switch in such route, and switch control relays controlled directly by the energized route relays for operating the track switches to the positions required for such route.

7. An interlocking control system according to claim 6, in which the pick-up circuit for each entrance relay includes back contacts of one or both route relays for a switch located in the routes having the corresponding entrance end, said route relays having energizing circuits including front contacts of the entrance relays for the opposite end of such routes.

8. An interlocking control system according to claim 6, in which the closing of the exit contact for the end of any route establishes a connection between the two directional circuits for such route over back contacts of the entrance relay for the exit end of such route to energize the route relays in one of said circuits by current supplied to the other directional circuit for the same route over a front contact of the entrance relay at the opposite end of said other directional circuit and in which a front contact of one of the route relays which picks up in response to the closing of said exit contact maintains the connection between the two directional circuits for the same route after said exit contact is opened.

9. An interlocking control system according to claim 6, in which back contacts controlled by that route relay which governs the conflicting position of a track switch located adjacent the entrance end of a route and occupying a trailing position with respect to the corresponding traific direction are located in the circuit for the corresponding entrance relay instead of in the circuit for the adjacent route relay which such entrance relay controls when energized.

10. An interlocking control system according to claim 6, in which a given route is normally unestablishable, a normally inactive switch lever for a switch in said given route, means for operating said switch individually to normal or reverse in response to the movement of said lever from an inactive position to the corresponding normal or reverse position, a normal and a reverse indication relay for said switch, means for energizing the corresponding normal or reverse indication relay when the switch assumes the position to which it is operated by said lever, and means for rendering said given route establishable in response to the operation of the entrance and exit contacts for its opposite ends, comprising a route circuit corresponding to said route including a front contact of that normal or reverse indication relay which becomes energized when, said switch is individually operated to the position required for thegiven route.

11. In an interlocking control system, a track layout including track switches adapted to form different traflic routes, a route button for each route end, a normal and a reverse route relay for each track switch for governing its operation to a corresponding position, normally inactive individual switch levers for operating the track switches to normal or reverse, normal and reverse indication relays for the track switches, means for energizing the normal or reverse indication relay for each track switch when it assumes the corresponding normal or reverse position in response to the operation of its individual switch lever, a route circuit network including a route circuit for each available route through the track layout each route circuit controlling that route relay for each switch of the corresponding route which governs the switch to the position required for that route, each route circuit also including a back contact of that indication relay for each switch of the corresponding route which becomes energized when that switch is individually operated to a conflicting position, means responsive to the successive operation of the two route buttons for the opposite ends of any route to supply current to the route circuit for such route to efiect the energization of one route relay for each switch of the route but only if the indication relay contacts in such route circuit are closed, and switch control relays controlled directly by the energized route relays for operating the track switches to the positions required for such route.

12. In an interlocking control system, a track layout including track switches adapted to form different traffic routes, a route button for each route end, a normal and a reverse route relay for each track switch, locking relays for the switches each of which is energized only when conditions are proper for operating the corresponding switch circuits including front contacts of the route relays and of the associated locking relays for eifecting the operation of the track switches to normal or reverse, normal and reverse indication relays for the track switches, means for energizing the normal or reverse indication relay for each track switch when the corresponding normal or reverse route relay is energized and the switch assumes the position to which it is operated by such route relay, a route circuit network including a route circuit for each available route through the track layout each route circuit controlling one route relay for each switch of the corresponding route for governing the switch to the position required for that route, each route circuit also including a back contact of that indication relay for each switch of the corresponding route which becomes energized when that switch is operated to a conflicting position, means responsive to the successive operation of the two route buttons for the opposite ends of any route to supply current to the route circuit for such route to affect the energization of one route relay for each switch of the route but only if the indication contacts in such route circuit are closed, and means efiective if a looking relay becomes released when the normal or reverse indication relay for the corresponding switch is energized to maintain such indication relay energized as long as said locking relay remains released.

13. In an interlocking control system, a track layout including'track switches adapted to form different tramc routes, signals at the ends of the routes for governing traffic movements through the track layout in opposite .directions, a route button for each signal location, a normal and .a reverse route relay for each track switch for governing its operation, a signal control relay for controlling each signal, 'a circuit network of interconnected route circuits including a distinctive circuit for each route over which one normal or reverse route relay for each track switch of such route and the signal control relay for the signal at one end or the other of such route all successively energized by current supplied to the circuit at the corresponding end, means responsive to the successive operation of the route buttons for the entrance and exit ends of a desired route to supply current to the corresponding route circuit to successively energize one route relay for each switch of such route and. to .prepare a circuit for that signal control relay which controls the signal at the entrance end of such route, and means including indication contacts controlled by the track switches for completing said prepared circuit when the switches assume the required positions as determined by the energized route relays to effect the clearing of the signal at the entrance end of the corresponding route.

14. An interlocking control system for selecting different traffic routes through a track layout provided with power operated track switches, comprising polarized switch control relays for operating the switches, an entrance and exit route button for each route .end, a normal and a reverse route relay for each track switch having front contacts for controlling the associated polarized relay, means responsive to the successive operation of the route buttons for the entrance and exit ends of any route to successively energize two series of route relays, those energized by the entrance button comprising one for each trailed switch and those energized by-the exit button comprising one for each facing switch in such route, and circuits for operating each polarized switch control relay to normal or reverse as required to establish said route including said front contacts of the normal or reverse route relay for the track switch which such polar-ized relay controls, the circuit controlled by a particular route relay of one series also including a front contact of an energized route relay of the other series which also controls another polarized relay associated with a different track switch in the same route.

15. An interlocking control system according to claim 14, in which the circuit for operating one switch control relay to the required position is controlled by one route relay only and that for operating another to the required positionincludes in series, a front contact of a route relay for the same track switch and a front contact of a route relay for another track switch facing in the opposite direction in said route.

16. An interlocking control system according to claim 14, in which the circuit for operating a particular switch control relay to one position is controlled by one route relay only and that for operating the same control relay to its other position includes in series, a front contact of the other route relay for the same track switch and a front contact of a route relay for another track switch facing in the opposite direction in the same route.

' 17.- An interlocking control system according to claim 14, in which the circuits (for operating each of the two switch control relays which control adjoining track switches facing in opposite directions .in said route to positions to establish such route, include in series, front contacts of the route relays for both switches.

18. In an interlocking control systemaccording to claim 14, in which the polarized control relay for a given track switch is operable to different positions to extend one or the other of two alternative routes having the same entrance end to a common exit end and the two route relays for the given track switch are arranged to be supplied with current from the same source, the circuit for each including a back contact of the other; a circuit for operating the polarized relay to the position required for one alternative route including a front contact of one of said route relays, a circuit for operating the polarized relay to the position required for the other alternative route including front con-' tacts of said other route relay and of a second route relay, said second route relay being one which controls a second track switch in said other alternative route, and means for bridging the back contact in the circuit for said one route relay to render said one alternative route establishable when both are available, comprising a back contact of said second route relay.

19. In an interlocking control system, a track layout including two tracks connected by a pair of track switches to form a crossover route when reversed and parallel routes when normal, a polarized switch control relay for controlling said track switches, a normal and a reverse route relay for each track switch, two normal energizing circuits for said switch control relay, one including a front contact of one normal route relay and the other a front contact of the other normal route relay, a reverse energizing circuit for said switch control relay including in series front contacts of both reverse route relays, means for selectively energizing said route relays to complete a circuit for said switch control relay, and means controlled by said switch control relay when energized for operating both track switches to normal or reverse.

20. In an interlocking control system, a track layout including two tracks connected by a pair of track switches to form a crossover route when reversed and parallel routes when normal, a polarized switch control relay for controlling said track switches, a normal and a reverse switch indication relay, an energizing circuit for each indication relay closed when the polarized relay is energized in the corresponding normal or reverse direction and the track switches are in the corresponding normal or reverse position, a normal and a reverse route relay for each track switch, manually controllable circuits for selectively energizing said route relays the circuit for each normal route relay including back contacts ofthe reverse route and indication relays and the circuit for each reverse route relay including back contacts of the normal route and indication relays, two circuits for energizing said polar-' facing in opposite directions, a normal and a reverse route relay for each switch, manually operable entrance and exit contacts and an entrance relay for each signal location, circuits for selectively energizing said entrance relays each including the associated entrance contact and a back contact of a route relay for a switch occupying a facing direction for the corresponding trafiic direction, a circuit for energizing one route relay for each switch which is in the trailing position for a given trailic direction in a given route including a front contact of the corresponding entrance relay, a pick-up circuit for one route relay for each facing switch in said given route including said entrance relay front contact, a back contact of the entrance relay for the opposite end of the route and the exit contact associated therewith, a holding circuit for one route relay for each facing switch in said given route including front contacts of one of said facing switch route relays and of said entrance relay, means controlled by the energized route relays for operating the track switches of the given route to the positions required for said route and for clearing the signal associated with the energized entrance relay when the switches assume such positions.

22. In an interlocking control system according to claim 21, in which a signal control relay is provided for each signal for governing its operation, and in which the signal control relays are controlled over a route agreement circuit network including a circuit for each route each of which includes the signal control relay for the signal at the entrance end of the route, a front contact of the associated entrance relay, and normally open contacts which close when the track switches of a route which such signal governs assume the positions to which they are controlled by the energized route relays, and means for supplying each such circuit with current over a back contact of the entrance relay for the exit end of the corresponding route, comprising a connection from such back contact to the holding circuit for the facing switch route relays established by the closing of the corresponding exit contact.

23. In an interlocking control system for the control of railway signals governing trafiic movements in two directions through a track layout in which power operated track switches provide difierent traific routes, route buttons for the ends of the routes, a normal and a reverse route relay for each track switch, an entrance relay for each signal location, a circuit for energizing each entrance relay controllable by the associated route button, route circuits for the different routes each arranged to be supplied with current over a front contact of the entrance relay associated with a route button which is operated to designate the corresponding point as the entrance end of a desired route to energize one route relay for each switch which occupies a trailing position in any route having its entrance end at that point, means comprising back contacts of the route relays thereby energized for rendering the entrance relays for the opposite ends of such routes non-responsive to the operation of their route buttons, means responsive to the operation of a route button for the exit end of a route having those route relays picked up which its entrance relay controls for energizing one route relay for each facing switch of such route over the same route circuit, means including back contacts of the route relays in that route circuit ior isolating it from route circuits for conflicting routes, and means controlled by said energized route relays for operating the track switches as required to establish the corresponding route and to clear the signal associated with the energized entrance relay when the switches assume such position.

24. In an interlocking control system according to claim 23, in which a signal is located at an intermediate point in a given route, a route button and an entrance relay being provided for controlling such signal, and in which the signal at one end of such route governs trafiic movements in one direction over a first portion of the given route extending only to said intermediate point, the signal at said intermediate point governs trailic movements in the same direction over a second portion of said route extending to its opposite end, and the signal at said opposite end governs traffic movements in the other direction over the entire route, a directional relay for each direction associated with said intermediate point and controlled over the route circuit for the given route, the energizing circuit for each directional relay including a front contact of the entrance relay for the corresponding end of such route and a back contact of the other directional relay, a circuit for controlling the entrance relay for each end of the given route by the associated route button including a back contact of the opposing directional relay, and a circuit for controlling the entrance relay for the signal at said intermediate point in response to the operation of its route button including back contacts of both directional relays.

25. In an interlocking control system according to claim 23, in which a signal is located at an intermediate point in a given route, a route button and an entrance relay being provided for controlling such signal, and in which the signal at one end of such route governs traffic movements in one direction over a first position of the given route extending only to said intermediate point, the signal at said intermediate point governs trafiic in the same direction over a second portion of said route extending to its opposite end, and the signal at said opposite end governs trafiic movements in the other direction over the entire route, a directional relay for each direction associated with said intermediate point and controlled over the route circuit for the given route, the energizing circuit for each directional relay including a front contact of the entrance relay for the corresponding end of the route and a back contact of the other directional relay, an exit stick relay for said intermediate point only, a pick-up circuit for said exit stick relay including a first portion of the route circuit for the given route controlled directly by the entrance relay for the first portion of such route and also including a back contact of the opposing directional relay and a normally open contact of said intermediate route button, means controlled by said exit relay when energized for sectionalizing the route circurit at said intermediate point, means for holding said exit stick relay energized over said first route circuit portion, means controlled by said exit stick relay for completing the route circuit for the first portion of the given route to effect the clearing of the signal for governing traific movements over said first portion of the given route, a circuit for controlling the entrance relay for the signal at said intermediate point in response to the operation of its route button

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