US2027569A - Interlocking system for railroads - Google Patents

Description

j&mo14,1@$@o N m INTERLOCKING SYSTEM FOR RAILROADS s SheetS -Sheet 1 Filed May 28, 1931 INVENTOR Jam 14,, 119360 5. N. WIGHT 2 227 56 INTERLOCKING SYSTEM FOR RAILROADS Filed May 28, 1931 3 Sheets-Sheet 2 am Li:

ATTORNEY Jam, 14 3936i s N WIGHT I ZMZZSGQ INTERLOCKING SYSTEM FOR RAILROADS Filed May 28, 1951 5 Sheets-Sheet 5 E v a x i \j Q Q'r W n4 2 F E Patented Jan. 14, 1936 UNITED STATES iPATENT OFFICE INTERLOCKING SYSTEM FOR RAILROADS Application May 28, 1931, Serial No. 540,596

30 Claims.

This invention relates to interlocking systems for railways, and more particularly to a system in which all of the interlocking is accomplished by electrical isolation.

In interlocking trafiic controlling devices in an interlocking system it is not only necessary to so interlock these various trafiic controlling devices that conflicting routes cannot be set up, but it is also necessary, or at least expedient, 10 to so interlock the various control circuits that if a particular route has once been set up this route cannot be disturbed by operating levers tending to set up a conflicting route until the lever governing the set-up route has been returned to its normal stop or no-route position, and in accordance with the present invention it is proposed to so organize the circuits that the proceed signal or signals of a particular set-up route cannot be put to stop by levers of conflicting routes. Another feature of the present invention resides in the provision of means for preventing the clearing of a signal if any of a plurality of control devices operating sequentia ly to control a switch machine associated with such signal assume non-corresponding positions. Another feature of the present invention resides in the provision of control means for switch machines which is only effective if the switch machine is in condition for operation at the time a lever is operated to cause such operation even though the lever is left in such operated position. Another feature of the present invention resides in the provision of route circuit portions which conform precisely with the various portions of the track layout, so that as a route is set up mechanically in the track rails, a corresponding route may be set up electrically in the route circuit portions, thus resulting in an exceptionally simple route circuit organization especially in a complicated track layout, this bucause the number of contacts in the interlocking circuit organization is directly proportional to the number of switches in the interlocking system. Another feature of this novel route circuit organization resides in the provision of means for setting up a particular direction of trafiic over the route represented by the route circuit eifective to prevent the setting up of trajhc in the opposite direction over such route.

Another feature of the'present invention as in a modified construction resides in the provision of wholly circuit interlocking means for obtaining the necessary and desired safety in the interlocking system, and in the provision of supplemental mechanical lever locking means to aid the operator against operating a lever which should not be operated.

One feature of the present invention is to so organize the switch machine control in its cooperation with the signal control that a signal cannot be cleared unless the switch control line circuit is intact at the time of such signal clearing. This is accomplished in accordance with the present invention by providing that the switch machine control relay be normally energized both when the signals are at stop and when the signals are at clear, and cause the clearing of such signals to be dependent upon the continued energization of such relay. This is more particularly accomplished by the including of a neutral contact on such switch control relay in the control for the signal circuits, and also by shifting the switch control relay from its control circuit to a stick circuit when a signal is cleared.

This feature has been shown in my later filed copending application Ser. No. 689,109, filed September 12, 1933, in which I am claiming all of the subject matter which is common with regard to the above mentioned feature.

Other objects, purposes and characteristic features of the invention will in part be obvious from the accompanying drawings and will in part be more specifically pointed out hereinafter.

In describing the invention in detail reference will be made to the accompanying drawings, in which:-

Fig. 1 shows a simple interlocking system involving only a single track switch and four associated signals embodying the present invention;

Fig. 2 shows in a schematic manner a more complicated interlocking system and the manner in which the signals thereof are controlled through the medium of the novel route circuit;

Fig. 3 shows how the switch machine lever of the system shown in Fig. 1 may be electrically locked; and

Fig. 4 shows how the circuits of Fig 3 may be modified, if desired.

Referring to Fig. 1, although the various devices may be housed in any suitable manner, it is proposed and it is believed expedient to house the apparatus shown within the dotted rectangle DO conventionally illustrating the interlocking ofiice, and to house the remaining apparatus exclusive of the switch machines and signals and their associated devices in a field station or sub-tower as conventionally illustrated by the dotted lines ST.

In the track layout shown, the track rails I0 have been shown divided by insulating joints l l into isolated sections for track circuiting purposes, of which the track circuits containing the detector track relay DT and the battery l2, the track circuit including the main track relay MT and a battery I3, and the side track circuit including a track relay TT and a battery l4, only have been shown. The track switch S for diverting traffic into the diverging route is preferably controlled by a switch machine SM, which for convenience has been illustrated conventionally without specifically showing its mechanism or operating motor.

The main track signal 20 governs trafi'lc from left to right over the track switch S on the main track, the low speed signal 2| governs east bound traiiic, from left to right, into the diverging route, the signal 22 governs west bound traffic on the main track, and the signal 23 governs west bound traffic oii of the diverging route. The switch machine SM is directly controlled by a two-position mechanical stick or permanent magnet stick master relay MB. This master relay MB is controlled jointly by the control relay Z and the master auxiliary relay MA. The switch machine repeater relay WP, repeats in the sub-tower ST the position of the track switch S, providing that this track switch S is in correspondence with the position of the master relay MR. The normal signal control relay NWP and the reverse signal control relay RWP are controlled jointly by the control relay Z and the switch machine repeater relay WP, these relays NWP and RWP being only energized one at a time if the relays Z and WP assume corresponding positions.

The lock relay L locks the control relay Z against operation and in turn locks the switch machine SM against operation. This lock relay L may be controlled in any suitable manner so long as it locks the switch machine SM against operation when it is improper to operate the associated track switch S, namely when a route has been cleared over this track switch or a route set up over this track switch has been accepted by a moving train, but preferably this look relay L is controlled in a manner as a similarly designated lock relay in the prior application of R. M. Phinney Ser. No. 463,940, filed June 26, 1930, is shown controlled.

In this sub-tower ST are also located for each signal a route relay and a signal relay. The route relay for the signals 20 and 2| have been designated 2i32|RR, the signal relay for the signal 20 has been designated 20G and the signal relay for the signal 21 has been designated ZIG. Similarly, the signal relay and route relay for the diverging route signal 23 have been designated 23G and ZSRR, respectively. Similarly, the signal relay and the route relay for the main track signal 22 have been designated 22G and 22RR, respectively.

Referring now to the interlocking tower DO attention is directed to the fact that a miniature track layout corresponding in every respect to the actual track layout is reproduced in the interlocking tower, with the switch machine levers located directly below the track switch, and the signal control buttons or switches preferably located directly in the tracks or routes conventionally representing the track layout. The button or key for controlling the signals 20 and 2| has been designated 30--3l. The key for controlling the signal 22 has been designated 32 and the key for controlling the signal 23 has been designated 33. Also, the switch machine lever for controlling the track switch S has been 5 designated SML; this switch machine lever SML has also associated therewith a lockout lamp LO, a transit light TL and a track circuit occupancy light TR.

Operation of Fig. 1.--Attention is directed to 10 the legend associated with the switch machine lever SML signifying that the contacts of this lever are preferably contacts of the snap-acting type, and cannot be held in an intermediate position, and that they move rapidly from one 15 extreme to the other extreme position upon movement of the lever. As shown the control relay Z and the indicating relay K are energized and included in the same series circuit which may be traced as follows:beginning at 20 the positive terminal of the battery 35, wire snap-acting contact 31, wire 38, lower winding of the relay K, wire 39, polar contact 46 of the relay WPP, line'wire 4i, front contact :2 of the lock relay L, wire 43, Winding of the relay 25 Z, wires 43, 45 and 46, to the midpoint of the battery 35. Attention is directed to the fact that deenergization of the lock relay L will not effect deenergization of the relay Z, but will eiiect deenergization of the relay K, the relay Z being 30 maintained energized through the following stick circuit:beginning at the positive terminal of the battery 41 located in the sub-tower ST, wire 48, polar contact 59 of the relay Z, wire 58, back contact 42 of the relay L, wire Q3, winding of 5 the relay Z, wire :34, connected to the midpoint of battery 47.

Attention is also directed to the fact that if the lever SML is operated while the lock relay L is deenergized and the relay K is deenergized, 4,0 subsequent energization of the lock relay L will not result in the control of the relay Z by the lever SML. This is true because the relay K is a stick relay and cannot be picked up unless the position of the lever SML.c0rresponds to the o5 position of contact 5! of the relay WPP, this switch machine repeater relay WPP of course assuming the position corresponding to of the track switch S, as more particularly described hereinafter. In other words, moving the 50 lever SML, and leaving it in its moved position, will not result in operation or" the switch machine if this lever SML was operated at the time the switch machine SM was locked against movement through the medium of the lock relay L.

Let us now assume that the operator moves the lever SML to a dotted position with the lock relay L energized. Under this condition the quick snap action of the contacts of the lever SML will prevent dropping of the relay K, the direction of the turns of the winding being such that the direction of magnetic fl X in the relay K is not reversed, which relay K is now included in series with the relay Z through the medium of its stick contact 5!, the relay Z being reversed by the flow of current due to this reversal of lever SML. This operation of the r lay Z will of course effect reversal of the polar contacts '59, 52, 53 and 54 of the relay Z, and with the contact 54 out of correspondence with the contact 55 of the master relay MR, the master auxiliary relay MA will be energized through a circuit readily traced in the drawings, and will result in closure of its contact 265. This completes the circuit for the master relay MR to effect operation of this master relay MR to its dotted position, in which position the contact 55 thereof again gets into correspondence with the contact ii -l of the relay Z, thereby again effecting deenergization of the auxiliary relay MA and the opening of its contact 26, resulting in deenergization of the master relay MR. The net result is, that the circuit for the master relay MR is closed just long enough to result in its operation, after which this operating circuit is again broken.

Movement of the master relay MR to its dotted position, will of course result in completion of the reverse circuit R of the switch machine SM, thereby effecting operation of the switch machine SM to its take-siding position. The moment the master relay MR was operated to its dotted position the circuit for the switch machine repeater relay WP was broken, this because the master relay MR was then out of correspondence with the point detector contacts 5% and El, and resulted in the relay WP being deenergized. This relay WP will of course remain deenergized until contacts 56 and 51 again come into correspondence with the contact 58 of the master relay MR, which will occur when the switch machine SM has completed its operating stroke. Also, operation of the control relay Z to its dotted position, as heretofore explained, causes the contact 52 thereof to get out of correspondence with the contact SE of the relay WP, thus resulting in deenergization of the relay NWP, the relay RWP also remaining deenergized. One or the other of these relays NWP or RWP will become energized through a circuit readily traced in the drawings just as soon as the relays Z and WP again assume corresponding positions.

The polar contact SI of the relay WP will apply current to a switch machine repeater relay WPP, located in the interlocking office D0 of a polarity corresponding to the position of the switch repeater relay WP, providing of course that the detector track relay DT is energized and its contact 63 is closed.

It is thus seen that the switch machine repeater relay WPP is energized when the detector track circuit is unoccupied, providing the master relay MR is in correspondence with the point detector contacts 55 and 51 of the switch S, so that the back contact fi l of the relay WPP may signify in the interlocking ofiice DO this condition of the traffic controlling devices in the field by illuminating one or the other of the transit lights TL or TR, these lamps being further selected by the contacts 65 of the stick relay K. This relay K is deenergized during track occupancy but is energized during the transitory period of switch machine operation. so that the transit light TL and the track occupancy light will be illuminated at the proper time. Also. s nce the locked condition of the switch machine SM is indicated by deenergization of the stick relay K, the hack contact 65 of this relay K. may be used to illuminate the look-out lamp L0, as i cated. If desired, the position of the track S'tlltCh S may be distinctively indicated through the polar contact 6'! of the relay WPP.

Having now explained how the switch S may be operated to the diverging route position, how the transitory condition of the switch is indicated the transit light TL and track occupancy is indicated by the lamp TR, how the switch machine locked condition is indicated by the lamp LO, let us observe how the various signals 29,

l6, 7?, 18 and '39.

2|, 22 and 23 are interlocked through route circuits which are built up out of various circuit elements combined in various combinations.

Let us assume that the normal relay NWP is energized and the reverse relay RWP is deenergized, as illustrated in the drawings, and let us assume that the operator wishes to set up eastbound traffic (moving from left to right) on the main track, and in order to do so operates his signal key 3i33l to a circuit closed position. Since the route relay 20-2lRR is deenergized the closure of the key 303l will result in closure of the following pick-up circuit for the stick relay 2il2lSS:beginning at the terminal (-I) of the suitable battery, key 3il3l, wire it, winding of the relay 2il-2lSS, wires H and 12, back contact 13 of the relay 202IRR, to the other terminal It should be noted that the relays 2i1-2lRR and 223R are connected in a closed series circuit, conveniently called a route circuit, but that the two ends of this circuit are normally connected to the same terminal of the battery, namely the minus terminal. Closure of the circuit for the relay 26-43586, just traced, will effect energization of this relay 2D2ISS and closure of its stick circuit through the medium of its stick contact i i and wire M will maintain it energized and will further eifect lifting of its contacts '15, Lifting of contact i5 will reverse the polarity of current applied to this contact thereby energizing the series circuit including the route relays 2il2iRR and EZRR, which may be traced as follows:--beginning at the terminal (-1-) of suitable way station source, front contact 65 of the relay 2il2lSS, wire 89, winding of the relay 2B-2iRR, wire 8|, front contact 32 of the relay NWP, wire 33, winding of the relay 22RR, wire lit, back contact of the relay ZZSS to the other terminal of said source.

Picking up of the relay 2il2iRR opens its contact l3 and closes its contacts 67 and 88. Energization of the relay ZZRR opens its contact 8i and efiects closure of its contact It will be noted, that the opening of contact 8% of the relay ZZRR prevents the stic: signal control relay rrss from being picked up by operation of the signal key Also, opening of contact "it of relay EEG-458R would prevent picking up relay til-HSS if it not already up. In other words, if a route circuit has once been energized by energization of a stick relay at one end of such route circuit, stick signal relay located at the other end of this route looking circuit is rendered incapable of changing the condition of the route circuit.

The circuits for the various signals, such as the signals ill, 22 and are so organized that its signal control stick relay, such as the stick relay 2il-2lSS, EESS or sees, and associated route relay, such as, E L-ZiRR, ZZRR or ESRR, must be both energized before the signal in question can be cleared. For instance, in connection with the signals and 2!, of which the operator is attempting to clear the signal said signal 2e cannot be cleared unless both the relays 2il2lSS and Bil-HER are both energized, as is now the case (see contacts iii and 811 of these relays).

The signal control relay is new energized through. the following circuitz -beginning at the terminal (-1-), front contact 92 of the detector track relay DT, wire til, front contact lid of the relay NWP, wire at, front contact 96 of the main track relay MT, wire 91, front contact 81 of the route relay 20--2IRR, wire 98, front contact 16 of the stick relay 20-2ISS, wire 89, winding of the relay 20G, wire I00, front contact ll of the relay 202ISS to the other terminal With the signal 29G energized, the signal 28 is cleared through the circuit including the front contact I35 of relay 28G and the wire I02. It should be noted that with relay 20-2ISS deenergized the relays 286 and 2IG are short-circuited through wires 68 and 59 respectively. This is done to protect against accidental energization of these relays, as by foreign currents. Attention is directed to the fact that relay 2IG for controlling the signal 2| cannot now be energized because the front contact I84 of the relay RWP, signifying the position of the track switch, is open. Also, operation of the signal key 2 will produce no effect, in that the circuit for the relay ZZTZSS controlled thereby is open at the back contact 29 of the relay 22RR, and operation of the key 3-3 for controlling the signal 23 is ineffective even though this key will effect energization of the signal stick relay 23SS, the contact IE5 of the relay 23RR still being closed. Lifting of the contact I66 of this relay'23SS will produce no result, because the circuit for the relay ZSRR is open at the front contact I! of the relay RWP. Putting it in different words, the various elements of the various route circuits may be combined to establish route circuits through the medium of contacts signifying the position of the track switches, and with a route circuit once established, the elements of route circuits which have not been included in the established route circuit, or circuits, will be ineffective and will maintain the associated signals at stop, and the elements which have been combined to establish a route circuit enable only a signal at one end of such route circuit to be cleared, this because if the signal relay at one end of the route circuit is energized it will lock the signal relay at the other end of this route circuit against energization. Although the signals 20, 2|, 22 and 23 may be either two-condition or three-condition and may be either light signals or semaphore signals, and may be controlled in accordance with traffic conditions in any suitable way, they have been shown conventionally as controlled by track relays of the track circuits in advance. For instance signal 2| is shown controlled through front contact I03 of signal relay 2K}, which relay 2IG is in turn controlled through front contacts 18, 88, 86, I94 and 92 of relays 232ISS, 29-2IRR, TT, RWP and DT respectively. Signal 22 is controlled through front contact I36 of signal relay 22G, which relay 22G is in turn controlled through front contacts I31, 90, I38 and I39 of relays DT, 22RR and 22SS, respectively. Also signal 23 is controlled by relay 23G through its front contact itii, which relay 23G is controlled through front contacts 93, MI, I42 and I43 of relay DT, 23RR and ZBSS, respectively.

In order to avoid complication in illustrating an interlocking system embodying the present invention, the invention has been shown applied to a rather simple track layout in Fig. l of the drawings, but to more clearly illustrate how the novel route circuits may be applied to a more complicated track layout without any material complication in the route circuits themselves, a route circuit having a more complicated interlocking feature has been illustrated in Fig. 2 of the drawings.

Referring to Fig. 2 of the drawings, which illustrates a portion of or an entire interlocking system including signals I, 2 and 3 for governing east bound traffic into such interlocking system and including signals 4, 5, 6 and I for governing west bound trafiic into the interlocking system, a cross-over H0 and track switches Iii, H2 and H3 having been illustrated to set up various routes. Routes may therefore be set up as followsz-signal I to signal 4, signal I to signal 5, signal 2 to signal 4, signal 2 to signal 5, signal 3 to signal 4, signal 3 to signal 5, signal 3 to signal 6 and signal 3 to signal I, and traiiic-may of course be set up in either direction over each of these routes. Levers L L L L L L and L' have been illustrated to control the signals I to I, inclusive, respectively. Similarly, each of the levers has associated therewith a signal stick relay SS having an exponent corresponding to the number of the signal it controls, resulting in relays SS SS SS SS SS SS and SS". Similarly, each signal stick relay has associated therewith a route relay, these route relays being designated RR with an exponent corresponding to the number of the signal associated therewith, resulting in route relays RR RR RR RR RR RR and RR".

It is desired to point out now, that it is necessary to have both the signal stick relay SS and the route relay RR for a particular signal energized before such particular signal can be cleared, this feature is illustrated in Fig. 2 but has been more fully pointed out in connection with the drawings in Fig. 1. By looking at the track layout in Fig. 2 of the drawings, it will be noted that two routes are set up as illustrated by the track rails and switch box contacts in the drawings, the first route extending from the signal 2 to signal 5, and the second route extending from signal 3 to signal I.

It should be noted that route circuits corresponding to these track routes are now closed, these route circuits may be traced as follows: (1) beginning at the terminal of a suitable way station battery, back contact II5 of the relay SS wire H6, winding of the relay BB wire II'I, switch box or switch position contact H8 (indicating the position of the switch III), wire H9, contact I20 (signifying the position of the cross-over Hi3), wire I2I, contact I22 (signifying the position of the switch H2), wire I23, winding of the relay RR wire I24, contact I25 of the relay SS in its retracted position, to the same terminal of the battery; and (2) beginning at the terminal of the way station battery, back contact I26 of the relay SS wire I21, winding of the relay RR wire I28, contact I28 (signifying the position of the track switch H3) wire I38, winding of the relay RR, wire I3I, back contact I32 to the same terminal It should now be noted that for the route leading from signal 2 to signal 5 either the signal 2 or the signal 5 may be cleared by moving the corresponding signal lever and picking up the corresponding signal stick relay, but that as soon as one of these stick relays is picked up the pole changing contact of this stick relay will apply ener y to the route locking circuit thereby picking up the route locking relays RR and RR thus resulting in looking the other stick relay against energization, all in a manner as already explained in connection with Fig. 1 of the drawings. In other words, traffic can only be set up in one direction over an established route, and with a particular route once established all of the route locking relays of conflicting routes will be open-circuited. For instance, in the particular track layout illustrated, and with the routes 2-5 and 3-? set up, the route locking relays RR BB and BB are open-circuited at the contact H8, I22 and 829, respectively.

It should further be noted that the particular routes that have been established cannot be disturbed by signal levers of conflicting route signals if the contacts I29, H8, I35, I20 and I22 are switch box or point detector contacts, andthese switches are locked against movement, also, it should be borne in mind that the various switch machines for operating the track switches and cross-over are locked against movement if traffic has been set up over such particular track switch or cross-over, as has already been explained and is accomplished by relay L. The net result is, that if a route has once beeset up and a signal has been cleared over such route, this signal cannot be put to stop by any lever except that lever used for controlling such signal. Or in other words, the progress of train movement over a selected route which has been cleared cannot be disturbed by a lever of a conflicting route, in spite of the fact that the levers of such conflicting signals or routes are not locked against movement.

Let us now assume that the switches H2 and M3 and the cross-over H9 are all operated to their dotted position, in which event a route extending from signal 3 to signal t, or from signal l to signal 3, is established. This particular route conflicts with all other possible routes, so that only one route can now be set up instead of two routes, as was the case heretofore. Under this assumed condition of the track layout, the route relays RR RR RR RR and RR" have their circuits open at the respective contacts M8, I263, I22, I35 and I29, respectively. One of the advantages of the novel route locking circuit organization shown in Figs. 1 and 2 resides in the fact that only a single contact for each switch is necessary even though such track switch is common to a large number of routes, so that a comparatively simple and inexpensive wiring installation is necessary irrespective of ti e complication of the track layout, and further that the route circuit organization is such that if a particular route circuit is energized from one end thereof the other end thereof is locked against interference with the first control, and vice versa.

Although th various track switches Ill, IIIZ and lit, the cross-over Hi1, and the signals I to l, inclusive, in Fig. 2 have been shown rather conventionally, it is desired to be understood each of the track switches ll, H2 and H3 and the cross-over HE) are preferably operated by suitable switch machines in the same manner as shown in Fig. 1, each of these switch mach les being at times locked against operation by a suitable lock-out relay as also shown in Fig. 1. Furthermore, each of the signals I to I, inclusive, are preferably controlled in the same manner are controlled the signals in Fig. 1 of the drawings, the detail circuit organization for 11 signal having been omitted from Fig. 2 for c venience and to avoid confusion, as is true the various switch machines which have been omitted from Fig. 2. In other words, if the interlocking system conventionally shown in Fig. 2 were illustrated in detail the lock relay for the switch machine for operating the track switch H2, for instance, would at times depend for its control on signal I and at other times on the fact whether signal 2 is clear or at stop, depending upon the position of the track switch HI, and at other times would depend upon the fact whether the signal 3 is at stop or proceed depending upon the position of the cross-over H and the track switch H3, all in a manner as clearly understood from the prior application of R. M. Phinney to which reference has been heretofore made. What has been said about the lock relay for switch H2 is also true of the lock relay for the track switches ll I and H3 and for the cross-over H0. In other words, Fig. 2 represents a complete interlocking system involving three track switches, a cross-over and seven signals of the two or three aspect type, together with all of the control circuits and route circuits to interlock the various signal switches and cross-overs to establish the various routes heretofore pointed out in detail, from which the switch machines and their control circuits as well as the control circuits for the signals have been omitted for convenience.

In Fig. 3 has been shown a modified portion of the system shown in Fig. 1. In this modified form of the invention a lever lock comprising an electromagnet I50 for operating the locking pawl I! has been added to the lever SML As shown, the electric lever lock Mil-I5! is controlled through the front contact 65 of the stick relay K this relay K corresponding in every respect to the relay K of Fig. 1 of the drawings. This lever lock l5lll5l is not provided to afford additional safety, but is merely added to afford additional facility, or rather to avoid an operator operating a lever when this lever should not be operated. As has already been explained in connection with Fig. 1 of the drawings the lever SML should never be operated when the relay K is deenergized, for such operation of the lever SML, even though it can do no particular harm, will result in no operation of anything except the lever itself, but it could possibly confuse the operator in that he might expect the distant switch 8 to respond thereto. As already explained, the lever SML if operated when the relay K is deenergized, must after energization of the relay L be returned to its previous position to eflfect reenergization of the relay K. In the arrangement shown in Fig. 3 the lever SML is locked immediately upon deenergization of the relay K so that the operator cannot operate the lever SML during the locked condition of the switch machine.

From a study of the arrangements shown in Fig. 3 of the drawings it will readily appear that the polar contact 48 of relay WPP and the stick contact 5| of the relay K perform substantially the same function that the electric lock I5U-I5l performs, in that each of these devices prevents the application of energy to the line wire M when the lock relay L is deenergized. Consequently, if it is desired to rely on the protection afforded by the lever lock I5Ill5l the polar contact 40 and the stick contact 5I may be dispensed with, and such an arrangement has been illustrated in Fig. 4 of the drawings. Also, if desired, the contacts 65 case the relay K may be omitted.

Applicant has thus shown several embodiments of his novel interlocking system, and has shown rather specific circuits and devices for carrying out the functions of his system, but it is desired to be understood that the specific system illustrated has not been selected for the purpose of showing the scope of his invention, nor has it been selected for illustrating the precise construction necessarily employed in practicing the invention, but has been illustrated for the purpose of facilitating disclosure of the underlying principles of the invention and the manner in which these principles may be applied to a particular track layout, and that various changes, modifications and additions may be made to adapt the invention to the particular problem encountered in practicing the same, all without departing from the spirit or scope of the invention, except as demanded by the scope of the following claims.

What I claim as new is:

1. In an interlocking system, the combination with a track lay-out including a track switch and a cross-over to establish a plurality of track routes, contacts associated with said switch and cross-over said contacts having circuit closing positions corresponding to the positions of their track points, wires connecting said contacts to establish route circuits corresponding to track routes established by said track switch and cross-over, a signal at each end of each track route, an interlocking contact at each end of each route circuit normally connected to one terminal of a source of current but movable to connect with the other terminal of said source, a route relay near each end in each route circuit, a stick relay for operating said contact and having a pick-up circuit including a back contact of the associated route relay, whereby only the interlocking contact at one end of said route circuit can be operated from normal, and a control circuit for the associated signal including in series a front contact of the associated stick relay and the associated route relay.

2. In an interlocking system of the electrical isolation type, the combination with a track lay-out including a track switch, a plurality of signals for governing traffic in both directions over the two routes establishable by said track switch, a switch machine for operating said track switch, lock-out means for preventing operation of said switch machine, a circuit including a lever operated contact for controlling a relay for in turn controlling said switch machine and permitting control of said relay only if the act of closure of said contact occurs when said lock-out means is inactive, an indicating relay for indicating the position of said switch machine and whether it is in correspondence with its control relay, three route circuit portions, and two route circuits for interlocking said signals each including two of said route portions and a contact of said indicating relay.

3. In an interlocking system of the electrical isolation type, the combination with a track lay-out including a track switch, a plurality of signals for governing trafiic in both. directions over the two routes establishable by said track switch, a switch machine for operating said track switch, lock-out means for preventing operation of said switch machine, a circuit including a lever operated contact for controlling a relay for in turn controlling said switch machine and permitting control of said relay only if the act of closure of said contact occurs when said lock-out means is inactive, an indicating relay for indicating the position of said switch machine and whether it is in correspondence with its control relay, three route circuit portions, and a contact operated by said track switch for connecting said circuit portions to establish route circuits each corresponding to the track route then established.

4. In an interlocking system of the electrical isolation type, the combination with a track layout including a track switch, a plurality of signals for governing traflic in both directions over the two routes establishable by said track switch, a switch machine for operating said track switch, lock-out means for preventing operation of said switch machine, a circuit including a lever operated contact for controlling a relay for in turn controlling said switch machine and permitting control of said relay only if the act of closure of said contact occurs when said lock-out means is inactive, an indicating relay for indicating the position of said switch machine and whether it is in correspondence with its control relay, three route circuit portions each corresponding to a track portion isolatable by said track switch, a contact operated by said track switch for connecting said circuit portions to establish route circuits each corresponding to the track route then established, a lever for each circuit portion thus resulting in a lever for each end of each route circuit, and means for rendering the lever at one end of a route circuit ineffective upon operation of the lever at the other end of such route circuit.

5. In an interlocking system, route control means comprising, a circuit including contacts which assume positions corresponding to the positions of associated track switches, a route relay at each end in said circuit, means for energizing said circuit from each end, and means for preventing de-energization of said circuit from one end if it has been energized from the other end.

6. In an interlocking system, a route control means comprising, a circuit including contacts assuming positions corresponding to the positions of associated track switches, a route relay at each end in said circuit, contacts for energizing said circuit from each end, a signal associated with each end of each route circuit, and interlocking means including the route relays of said circuit for allowing operation of the contacts at one end at one time only and for allowing clearing of the signal only at that end of said circuit.

7. In an interlocking system, route control means comprising, a circuit including contacts assuming positions corresponding to the positions of associated track switches, a route relay at each end in said circuit, means for energizing said circuit from each end, a stick relay associated with each route relay, a signal associated with each route relay, and interlocking means including the route relays of said circuit and the associated stick relays for allowing energization of said circuit at one end at a time only and for allowing clearing of the associated signal at that end of said circuit only.

8. Route control means for interlocking systems comprising, a circuit connecting two route relays and including said relays in series, interlocked means for allowing energization of said circuit from one end ata time only, a signal associated with each of said route relays, and means for allowing clearing of only that signal associated with the route relay at the end at which the energization of said circuit is accomplished.

9. Route control means for interlocking systems comprising, a circuit connecting two route relays and including said relays in series, interlocked means for allowing energization of said circuit from one end at a time: only, a signal associated with each of said route relays, a stick relay associated with each route relay and having a front contact for energizing said route ircuit and having included in its energizing circuit a back contact of the associated route relay, a signal for each route relay, and a clearing circuit for each signal including a front contact of the associated route relay and front contact of the associated stick relay in series.

10. A route circuit for allowing traffic on a railway system to move in one direction over a particular route only comprising, a line wire having a first relay at each end said first relays being connected in series, a second relay associated with each of said first relays and for energizing said line wire from the corresponding end, and contacts on such first relay for rendering such second relay ineffective to energize said line wire upon energization of such first relay unless such second relay has already energized said line wire.

11. Route control means for allowing railway traflic to move in one direction only over a particular route comprising, a route circuit connecting opposite ends of a route, a first relay at each end in said route circuit for manifesting the energized condition of said route circuit, said first relays being at all times included in series in said circuit, a second relay at each end of said route for energizing said circuit from the corresponding end, and means for interlocking said first and said second relay at each end of said route to prevent said circuit from being changed from that end if it has been energize from the other end.

12. Route control means for allowing railway traffic to move in one direction only over a particular route comprising, a circuit connecting opposite ends of a route, a first relay at each end of said route for manifesting the energized condition of said route, said first relays being at all times included in series in said circuit, a second relay at each end of said route for energizing said circuit from the corresponding end, and a circuit for each of said second relays including a back contact of the associated first relay.

13. Route control means for allowing railway trafiic to move in one direction only over a particular route comprising, a route circuit connecting opposite ends of a route, a first relay at each end of said route for manifesting the energized condition of said route circuit, said first relays being at all times included in series in said circuit, a second relay at each end of said route for energizing said circuit from the corresponding end, a circuit for each of said second relays including a back contact of the associated first relay, and a contact on each of said second relays included in said route circuit.

i l. A route circuit for allowing traffic on a railway system to move in one direction over a particular route only comprising, a line wire having contacts included therein manifesting that said particular route has been set up and having a first relay at each end, said first relays being connected in series, a second relay associated with each of said first relays and for energizing said line Wire from the corresponding end, and contacts on such first relay for render-- ing such second relay ineffective to energize said line wire upon energization of such first relay unless such second relay has already energized said line wire.

15. Route control means for allowing railway trafiic to move in one direction only over a particular route comprising, a route circuit having contacts included therein manifesting that said particular route has been set up and connecting opposite ends of a route, a first relay at each end in said route circuit for manifesting the energized condition of said route circuit, said first relays being at all times included in series in said circuit, a second relay at each end of said route for energizing said circuit from the corresponding end, and means for interlocking said first and said second relay at each end of said route to prevent said circuit from being changed from that end if it has been energized from the other end.

16. Route control means for allowing railway traffic to move in one direction only over a particular route comprising, a circuit having con-- tacts included therein manifesting that said par-- ticular route has been set up and connecting opposite ends of a route, a first relay at each end of said route for manifesting the energized condition of said route, said first relays being at all times included in series in said circuit, a s cond relay at each end of said route for energizing said circuit from the corresponding end, and a circuit for each of said second relays including a back contact of the associated first relay.

17. Route control means for allowing railway traific to move in one direction only over a particular route comprising, a route circuit having contacts included therein manifesting that said particular route has been set up and connecting opposite ends of a route, a first relay at each end of said route for manifesting the energized condition of said route circuit, said first relays being at all times included in series in said circuit, a second relay at each end of said route for energizing said circuit from the corresponding end, a circuit for each of said second relays including a back contact of the associated first relay, and a contact on each of said second relays included in said route circuit.

18. In combination, a plurality of routes over a railway system each including a plurality of track switches, a route circuit for each route including contacts assuming positions corresponding to the positions assumed by said track switches in the corresponding route, a signal relay located at each end of each route circuit and included therein so as to be energized when such route circuit is energized from the opposite end, a second relay associated with each signal relay, front contacts on each of said second relays for energizing its route circuit from its particular end, and means preventing the energization of such second relay to close said front contacts when its associated route circuit has already been energized from the other end.

3.9. in combination, two signals governing traffic in opposite directions over the same track, a line circuit extending from one to the other of said signals, a signal relay associated with each of said signals for when energized permitting clearing of such signal, a second relay associated with each of said signal relays, front contacts on each of said second relays for energizing said circuit from its end, and means for preventing the energization of such second relay to close said front contacts when said circuit has already been energized from the other end.

20. In combination, a section of railway track including a track switch, power operating means for the track switch, manually controlled means for governing the operation of said power operating means, indication means for indicating the position of said track switch and its correspondence with said manually controlled means, a route circuit for each route through said section including contacts of said indication means, a signal relay located near each end of each route circuit and energized when such circuit is energized, a second relay associated with each signal relay, contacts on each of said second relays for energizing its route circuit from its particular end, means preventing the control of said energized route circuit by said second relay at the opposite end while such route circuit is energized, and means preventing operation of said manually controlled means when any route circuit is energized.

21. In combination, a section of railway track including a track switch, a switch machine for operating the switch, a control relay for controlling the operation of said switch machine, a control lever for controlling said control relay, an indicating relay for indicating the position of the track switch and its correspondence with said control relay, route circuit portions conforming to the track section and track switch layout, means including contacts of said indication relay to complete route circuits corresponding to the mechanical route then set up, a route relay located at each end of each route circuit and included therein so as to be energized when such route circuit is energized, a signal lever repeating relay associated with each route relay for energizing when actuated by its lever any route circuit in which its route relay may then be included, means for preventing the actuation of a signal lever repeating relay when its associated route relay is energized by the signal lever repeating relay at the opposite end of the then completed route circuit, a signal for each signal lever repeating relay and its associated route relay and controlled jointly thereby, and means preventing the response of said control relay to said control lever when a route circuit including contacts of said indication relay is energized.

22. A route circuit for allowing traffic on a railway system to. move in one direction only over a particular route comprising, a line circuit having a first relay at each end in said circuit said first relays being connected in series in said circuit, a second relay associated with each of said first relays and for energizing said line circuit from the corresponding end, contacts on each of said first relays open when each such first relay is energized for rendering the associated second relay ineirective to initially energize said line circuit, and a signal controlled by each of said first relays, said signals governing trafiic in opposite directions over said particular route.

23. In combination, a stretch of railway track including a track switch, a signal at each end of said stretch for governing the movement of traiilc into said stretch from that end, power operated means for operating said track switch, switch control means for controlling said power operated means, a circuit portion closed only when said switch control means and said power operated means assumes corresponding positions, a traffic governing relay for each of said signals which must be energized to permit clearing of such signal, a route circuit between said trafiic governing relays and including said circuit portion, one terminal of a current source connected at each end of said route circuit for supplying potential of one polarity to said circuit, manually controlled means for disconnecting one of said terminals and connecting another terminal of said source to said circuit to energize one of said route relays whereby a plurality of route circuits include the same contacts, and a particular route circuit cannot be closed unless said switch control means and said power operated means assume corresponding positions.

24. In combination, a stretch of railway track including a track switch, a signal at each end of said stretch for governing the movement of trafiic into said stretch from that end, power operated means for operating said track switch, independent and manually governable switch control means for controlling said power operated means to thereby operate said track switch to normal and reverse positions, a circuit portion closed only when said switch control means and said power operated means assume corresponding positions, a route circuit extending from one to the other of said signals and including said circuit portion, one terminal of a source of current connected to each end of said route circuit for supplying current to said route circuit to clear one only of said signals at one time, a manually controlled relay for disconnecting said terminal and connecting the other terminal of said source to said circuit to energize said circuit, whereby a plurality of route circuits include the same contacts and a particular route circuit cannot be closed unless said switch control means and said power operated means assumes corresponding positions.

25. In combination, a stretch of multiple railway track including a plurality of track switches, a signal at each starting point of track routes over said track for governing the movement of traffic into such route from that end, separate power operated means for operating each track switch, switch control means for controlling each power operated means, a circuit portion for each switch closed only when the switch control means and its associated power operated means assumes corresponding positions, a tramc governing relay for each of said signals which must be energized to permit clearing of such signal, a route circuit between said traffic governing relays and including a circuit portion for each switch in such route, one terminal of a current source at each end of said route circuit for supplying current to said circuit but normally ineffective, manually controlled means for disconnecting one of said terminals and connecting the other terminal of said source to said circuit, whereby said route circuit cannot be closed unless each switch control means and its power operated means assume corresponding positions. 26. In an interlocking system, a track layout including a track switch, signals for governing trafiic in both directions over said track switch in both of its positions, a switch machine for operating said track switch, a control lever for controlling the operation of said switch machine, locking means for preventing operation of said switch machine when any of said signals are cleared, three route circuit portions each corresponding to a track portion isolatable by said track switch, contact means operated in accordance with the position of said track switch for connecting said circuit portions to establish route circuits each corresponding to the track route then established, a signal lever for each end of said route circuits for energizing an established route circuit from its end, means preventing a signal lever from either energizing or deenergizing an established route circuit which is energized from the opposite end, and means for clearing the signal corresponding to that end of a route circuit at which such route circuit is energized dependent upon said signal lever for that end and dependent upon the energization of such route circuit.

27. In an interlocking system, a track layout including a track switch, signals for governing traffic in both directions over said track switch in both of its positions, a switch machine for operating said track switch, a switch control relay for controlling the operation of said switch machine, a switch control lever for governing said control relay, locking means for preventing control of said switch control relay by said lever when any of said signals are cleared and for permitting control of said switch control relay by said lever only if the actuation of said lever occurs while said signals are at stop, three route circuit portions each corresponding to a track portion isolatable by said track switch, contact means operated in accordance with the correspondence between said track switch and said switch control relay for connecting said circuit portions to establish route circuits each corresponding to the track route then established, a signal lever for each end of said route circuits for energizing an established route circuit from its end, means preventing a signal lever from either energizing or deenergizing an established route circuit which is energized from the opposite end, and means for clearing the signal corresponding to that end of a route circuit at which such route circuit is energized dependent upon said signal lever for that end and dependent upon the energization of such route circuit.

28. In combination, two route relays, a route circuit connecting said route relays in series, a stick relay associated with each route relay and having a front contact for energizing said route circuit from its end, a pick-up circuit for each of said stick relays including a back contact of its associated route relay, a stick circuit for each of said stick relays independent of the condition of any route relay, and means controlled jointly by each of said stick relays and its associated one of said route relays.

29. In combination; a first group of route relays; a second group of route relays; circuit means for selectively connecting route relays of said first group in series with route relays of said second group in different combinations to form route circuits, each of which includes two route relays; a stick relay associated with each of said route relays in both said groups, each stick relay having a front contact for energizing any route circuit in which its route relay may be connected, a pick-up circuit for each of said stick relays including a back contact of its associated route relay, a front contact of each stick relay for shunting out said back contact of its respective route relay, and means responsive to the picking up of a route relay only when its associated stick relay is picked up.

30. In combination; a first group of route relays; a second group of route relays; circuit means including a plurality of independently operable contacts for selectively connecting route relays of said first group in series with route relays of said second group in difierent combinations to form route circuits, each of which includes two route relays; a stick relay associated with each of said route relays in both said groups, each stick relay having a front contact for energizing any route circuit in which its route relay may be connected, a pick-up circuit for each of said stick relays including a back contact of its assicated route relay, a front contact of each stick relay for shunting out said back contact of its respective route relay, and means responsive to the picking up of a stick relay only when its associated route relay is picked up.

SEDGWICK N. WIGHT.

DISCLAIMER 2,027,569 Sedgwtck N. Wight, Rochester, N. Y. INTERLOCKING SYsTEM FOR RAIL- ROADS. Patent dated January 14, 1936. Disclaimer filed June 8, 1937, by the assignee, General Railway Signal Company.

Hereby enters this disclaimer by disclaiming from claim 20 any system, except wherein the signal relay located near each end of each route circuit is responsive to the energization of the route circuit so that both of the signal relays are energized when such circuit is energized; and by disclaiming from claims 23 and 25 any system, except wherein the traffic governing relay for each of said signals is responsive to the energization of the route circuit between said traffic governing relays, so that both of these relays are energized when. such route circuit is energized.

[Oflictal Gazette June 29, 1937.]

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