US2044241A - Railway traffic controlling apparatus - Google Patents

Description

June 16, 1936.

c. w BELL RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Feb. 1, I955 l n I w n. S w a balmy c A. V. B

MBSQQN Patented June 16, 1936 Niso s'r PATENT OFIE RAILWAY TRAFFIC CONTROLLING APPARATUS Application February 1, 1935, Serial No. 4,548 Renewed November 9, 1935 14 Claims.

My invention relates to railway traffic controlling apparatus of the type involving switches and signals.

More specifically, my invention relates to apparatus for controlling the movement of trafiic over stretches of single track connected by switches with the converging ends of multiple track stretches, such, for example, as a stretch of single track, commonly known as a gauntlet, connected by a spring switch at each end with a stretch of double track.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view illustrating one form of apparatus embodying my invention.

Referring to the drawing, the reference character Y designates a stretch of single track railway, at times hereinafter referred to as a switch section, connected at one end with tracks W and W! of a stretch of double track by means of switch F. The stretch Y is connected at the other end with tracks Z and ZI of another stretch i of double track by means of switch G.

Each of the switches F and G may be biased to a normal position, in which each switch is shown in the drawing, by some suitable means which may, for example, be of the well-known spring type. Each of the switches may be manually movable to its reverse position by suitable means not shown in the drawing, and may also be movable to itsreverse position by a train going over the switch in the trailing direction, that is, switch F may be movable to its reverse position by a train going over it from track WI to stretch Y, and switch G may be movable to its reverse position by a train going over it from track Z to stretch Y.

The normal direction for eastbound traific is, as indicated by the arrows, from track wt to track 2!, and the normal direction for westbound trafic is, as indicated by the arrows, from track Z to track W. Since switches F and G are spring switches, it is readily apparent that both eastbound and westbound trafiic may move in the normal direction to and from the single track stretch Y without stopping to manipulate such switches. But it is also evident that since switches F and G may be operated manually, both eastbound and westbound trafiic may, if desired, move from the single track stretch against the normal direction of trafiic by manually reversing the switch at the leaving end of the stretch Y.

- In other words, all trains, except those leaving stretch Y against the normal direction of traflic, may move over switches F and G without stopp ng.

The rails of stretchY and tracks W, WI Z and ZI are divided by means of insulated joints 5 5. into sections AB, AIBI, BC, 0-D, and ClDl. A track circuit is provided for each of the sections AB to Cl-Dl, inclusive. Each such track circuit includes a track battery 6 connected across the rails adjacent one end of the 10 section, and a track relay designated by the ref-, erance character T with a distinguishing prefix and connected across the rails adjacent the other end of the section.

The signals designated by the reference characters l and 4 govern the movement of traflic in the trailing direction over switch F from tracks W and WI, respectively, to stretch Y; and the signals designated by the reference characters 2 and 3 govern the movement of trafiic in the trailing direction over switch G from tracks ZI and Z, respectively, to stretch Y.

Associated with each of the signals I, 2, 3 and G is a signal control relay, designated by the reference character H with a suitable distinguishing prefix corresponding to the associated signal, and effective when. energized to cause the corresponding signal to display a proceed indication, but elfective when deenergized to cause such signal to display a stop indication. If the stretch Y is unoccupied, any signal control relay may be energized by the occupancy of the approach section immediately in rear of the associated signal by a train approaching such signal, provided no other signal control relay is energized. The wellknown circuits for the control of the signal lamps or mechanisms by the signal control relay have been omitted for the sake of simplicity.

Associated with each signal control relay is an approach locking relay designated by thereference character M with a suitable. distinguishing prefix corresponding to the signal with which such control relay is associated and effective when deenergized to prevent the energization of the other signal control relays.

Associated with each signal control relay is a directional stick relay designated by the reference character S with a suitable distinguishing prefix corresponding to the signal with which such control relay is associated and effective when energized to prevent the energization of the associated signal control relay when a train is receding from stretch Y.

Associated with each of the switches F and G is a switch indicating relay designated bythe relerence character P with a suitable distinguishing prefix corresponding to the associated switch. The relays IS and 4S are selectively controlled in accordance with the position of relay FF, and the relays 2S and 3S are selectively controlled in accordance with the position of relay GP.

The switch F governs three contacts 8 and 9, and the switch G governs three contacts H], II and I2 in accordance with the position of the governing switch, by any usual and well-known means.

In order to simplify the drawing, the relay contacts in some instances have not been placed directly under the relay actuating such contacts. I have, however, provided each such contact with a reference character having a suitable distinguishing prefix corresponding to the reference character of the actuating relay.

The signal control relay |H is provided with a circuit which passes from terminal X of a suitable source of current through front contact |3 of track relay BT, front contact M of approach locking relay 4M, front contact l5 of approach locking relay 2M, front contact N5 of approach locking relay 3M, back contact [1 of directional stick relay |S, back contact |8 of track relay AT, switch indicating contact 8 and relay IE to terminal O of the same source of current.

The signal control relay 31-1 is provided with a circuit which passes from terminal X over the same path as that just described for relay |H up to and including front contact l5 of relay 2M and thence, through front contact [9 of approach locking relay IM, back contact 20 of directional stick relay 38, back contact 2| of track relay DT, switch indicating contact II and relay 3H to terminal 0.

Signal control relay 41-1 is provided with a circuit which passes from terminal X through front contact 22 of track relay BT, front contact 23 of approach locking relay 3M, front contact 24 of approach locking relay IM, front contact 25 of approach locking relay 2M, back contact 26 of directional stick relay ES, back contact 21 of track relay AIT, switch indicating contact 9, and relay All to terminal 0.

Signal controlrrelay 2H is provided with a circuit which passesfrom terminal X over the same path as just described for relay 5H up to and including front contact 24 of relay IM, and thence through front contact 23 of approach locking relay 4M, back contact 29 of directional stick relay 2S, back contact 30 of track relay DIT, switch indicating contact l2 and relay 2H to terminal 0.

Approach locking relay |M is provided with a pick-up circuit which includes back contact 3| of signal controlrelay lH, front contact 32 of track relay BT and front contact 33 of relay AT, and with a stick circuit which also includes back contact 3| of relay |H and front contact 34 of relay |M.

Approach locking relay 2M is provided with a pick-up circuit and stick circuit each including back contact 35 of relay 2H, the pick-up circuit also including front contact 38 of relay BT and front contact 31 of relay DIT, and the stick circuit including front contact 38 of relay 2M.

Approach locking relay SM is provided with a pick-up circuit and a stick circuit each including back contact 39 of relay 3H, the pick-up circuit also including front contact 40 of relay BT, front contact 4| of relay DT, and the stick circuit including front contact 42 of relay 3M.

Approach locking relay 4M is provided with a pick-up circuit and a stick circuit each including back contact 43 of relay 41-1, the pick-up circuit also including front contact 44 of relay BT, front contact 45 of relay A|T and the stick circuit including front contact 43 of relay 4M.

Directional stick relay |S is provided with a pick-up circuit which includes back contact ll of switch indicating relay FP, back contact 48 of track relay BT and front contact 49 of approach locking relay IM, and with a stick circuit which includes back contact 41 of relay FP, back contact 50 of track relay AT and front contact 5|, of relay IS.

Directional stick relay 2S is provided with a pick-up circuit and stick circuit each including a back contact 52 of relay GP, the pick-up circuit also including back contact 53 of relay BT and front contact 54 of relay 2M, and the stick circuit including back contact 55 of relay DiT and front contact 56 of relay 2S.

Directional stick relay SS is provided with a pick-up circuit which includes front contact 5'! of relay GP, back contact 58 of relay BT and front contact 553 of relay 3M, and with a stick circuit which includes back contact 635.1 of relay ET and front contact SI of relay 3S.

Directional stick relay GS is provided with a pick-up circuit which includes front contact 62 of relay FP, back contact 63 of relay BT, front a contact i i of relay 8M, and with a stick circuit including back contact 55 of relay MT and front contact 36 of relay :8.

Switch indicating relay FF is provided with a pick-up circuit which includes normally open switch indicating contact '8, and with a stick circuit which includes back contact 61 of track relay BT and front contact 68 of relay FP. Switch indicating relay GP is provided with a pick-up circuit which includes normally open switch indicating contact l3 and with a stick circuit which includes back contact 89 of relay BT and front contact iii of relay GP.

Having described in general the form of apparatus which is shown in the accompanying drawing, I will now describe in detail the operation of the apparatus.

I shall first assume that, with all parts in their normal condition as shown in the drawing, a train on track W, desiring to move through stretch Y to track ZI, enters section AB. The entrance of the train into section AB will release track relay AT which will close its own back contact I3 to complete the circuit for the energization of signal control relay II-I.

The release of relay AT will'also open its front contact 33 in the pick-up circuit for approach locking relay |M to insure, as will be explained more in detail later, that relay IM, upon becoming deenergized, will so remain while section AB is occupied.

Upon the energization of relay IH, the signal I will be caused, by means of circuits not shown in the drawing, to display a proceed indication. The energization of relay IH will open its back contact 3| which will release approach locking relay IM. The releasing of relay IM will open its own front contacts l9 and 24 in the control circuits for signal control relays 3H, and 2H and 4H, respectlvely, thereby preventing, as long as relay ill l remains deenergized, the energization of each relay 2H, 3H and 4H even if the approach section associated with the signal controlled by any Zing of relay l M will also relay is so that relay is, as

open its own front contact 38 in the pick-up circuit for directional stick will be explained more in detail later, will not become energized when section BCl becomes occupied and, back contact (l3 of track relay BT becomes closed.

I shall next assume that the train, in response to the proceed indication displayed by signal I, has moved over the switch F and has entered section B-Ci, thereby releasing track relay ET. The releasing of relay BT will open its front contact E3 in the control circuit for relay ill, will open its front contact 32 in the pickup circuit for relay IM, and will close its back contact 53 in the pick-up circuit for directional stick relay 2S. The opening of front contact l3 will cause relay EH to become deenergized so that signal i will display a stop indication. The opening of front contact 32 will prevent relay l M, "as will be explained more in detail later, from becoming energized, as long as section 3-09 is occupied even thoughback contact .3! of relay lI-I will become closed. The closing of back contact 55 will energize directional stick relay 25 which, as will be explained later, will prevent signal 2 from clearing when section ClDl becomes occupied by the train.

I shall now assume that the train has entered section l-Dl thereby releasing track relay DiT which will close its own back contact 55 to complete the stick circuit for relay 28, so that relay 23 will be maintained in the energized condition as long as the train occupies section ClDl, and thereby interrupt the control circuit for signal control relay 21-: by the opening of back contact 28 of relay ES to prevent the energization of signal control relay 2H upon the closing of back contact 36 of relay DlT. Since relay 2S will remain energized as long as section Ci-Dl is cocupied signal 2 will not clear upon the occupancy of section Ol-Dl by a train receding from stretch Y, and such train is, therefore, prohibited by signal 2 from reversing its direction and again entering stretch Y without first clearing section l-Dl, which will permit another train already occupying one of the other approach sections to receive a clear indication to proceed over the stretch Y as soon as section BCl becomes unoccupied.

I shall now assume that the train has cleared section E-Cl so that track relay ET is again energized and its front contacts 53 and 22 will become closed to establish the control circuits for relays lI-I, 3H and ll-I. It is apparent that any one of th other signals may now be cleared upon occupancy of the associated approach section. When the train has cleared section {Ii-Di, the relay DlT will again become energized thereby opening its back contact 55 to restore relay is to its initial condition.

It will be noted that when any of the approach locking relays, such, for example, as relay lM, becomes deenergized as a result of the energization of signal control relay H in response to the occupancy of section AB by a train, the relay 5M will be held in its deenergized condition by front contact 33 of track relay AT until such time as the train clears section A-B, even though relay 2H may become deenergized and its back contact 3i become closed. This arrangement insures that relay l M will not become energized while section A-B is occupied in the event that signal control relay EH should accidentally become deenergized after the signal has been tive to prevent the section A--B with indication by .means .to the proceed became interrupted clearedby 'aLtrain approaching signal J! in section A B. Since relay IM, when deenergized, is effecclearing of the opposing signals, it is evident that, even if relay lH- should become deenergized, proceed indication authorizing movement into stretch Y while section AB is occupied.

It will also be noted that, if relay HT is in its normal deenergized position, the directional stick relay is associated with approach locking relay l M will be energized by the closing of back contact 58 of track relay BT provided front contact as of relay iM isclosed. Since, however, relay i M remains deenergized as long as relay BT remains released, the relay lM will not be energized upon the occupancy of section B-Cl by a train coming from section A-B. This arrangement provides a following train occupying a proceed indication as soon as the first train has cleared section B-Cl.

It is readily apparent without further explanation that, since the relays 2M, 3M and 4M, and relays 3S and 43 are controlled by similar circuits, these relays, in conjunction with associated signal control relays 2H, 3H and ll-I perform the same functions in the same manner as just described for relays IM, 68 and EH.

I shall next assume that, with all parts again in their normal condition, a train on track WI, desiring to move through. stretch Y to track Z, enters section Al-Bl. The entrance of the train into section All3l will release track relay AiT which will close its own back contact 21 to complete the circuit for the energization of ignal control relay I-I. Upon the energization of relay @H the signal 4 will display a proceed of circuits not shown in the drawing. The 'energization of relay ll-I will open its own back contact 63 which will release relay The releasing of relay QM will open its own dM. front contact 28 in the control circuit for relay 2H, and will also open its front contact i l in the control circuits for relays lH and 3H, thereby preventing, as long as relay dM remains deenergized, the clearing of each of the conflicting slgnals should the approach section associated with such signal become occupied.

I shall now assume that the train, in response indication displayed by signal t, has moved over the spring switch F and has entered section B-C thereby releasing track relay ET. The releasing of relay BT will open its front contact 22 in the control circuit for relay 3H so that relay ll-I will become deen rgized to cause signal 5 to display the stop indication.

It will be noted that relay F? Will be energized by the closing of switch indicating contact J upon the reversal of spring switch by the action of the train trailing through the switch, and that relay FP will be held in its energized condition by the closing of back contact 6? of relay BT until such time as the train clears section B-C. t

energized, however, because its pick-up circuit by the opening of front contact o l of relay 6M. It is apparent, since relay is does not become energized upon the movement of the train from track W5 to stretch Y, that a following train occupying section Al- Bl may receive a proceed indication at signal a as soon as the first train clears section B-C.

I shall now assume that the train has reached switch G, and since the switchis normally biased no other train would receive a to a position which will direct tramc to track ZI, a trainman reverses switch G manually so as to direct the train into track Z. The reversal of the switch will close contact H) to complete the pickup circuit for switch indicating relay GP which will remain energized through its stick cirsuit over back contact 69 of track relay ET. The energization of relay GP will close its own front contact 5! to complete the pick-up circuit for directional stick relay 3S (back contact 58 of relay BT having been closed since the train first entered section B-C). The energization of relay 35 will open its own back contact 20 in the control circuit for signal control relay 3H so that relay 3H will not become energized by the closing of back contact 2! of relay DT upon the occupancy of section C-D.

I shall now assume that the train has entered section C--D, thereby releasing track relay DT which will close its back contact 60 to complete the stick circuit for relay 38 so as to hold relay SS in the energized condition until the train clears section C-D. The relay BT now becomes energized to close its front contacts l3 and 22 to reestablish the control circuits for relays. 1H, 2H and 4H. It is apparent, since relay 3H may not be energized as long as section (J-D is occu pied, that now any one of the other signals may be cleared upon the occupancy of the associated approach section. When the train has cleared section C-D, the relay D'I will again become energized and relay 38 will be restored to its initial condition.

From the foregoing description it will be seen that I have provided a simple, economical and reliable means for governing and facilitating the movement of traflic to and from a stretch of single track connected by a switch to a stretch of multiple track. My invention provides for the automatic clearing of each signai upon occupancy of an approach section by a train approaohing such signal, only if no other signal is clear and then only if the single track stretch is unoccupied. My invention further provides a means for preventing the clearing of each signal when the approach section associated with such signal is occupied by a train, receding from the signal, thereby permitting another train to receive a proceed indication to move over the single track stretch as soon as the stretch is cleared by the receding train.

I have described, for a few movements of traffic, the operation of one form of apparatus embodying my invention. From this description and from the accompanying drawing, the operation of the apparatus for every other possible movement of trafiic may be readily determined.

It is understood that, although I have described my invention as being particularly adapted for use in controlling the movement of traffic between two double track stretches connected by spring switches with a stretch of single track, my invention is not necessarily so limited, but may be applied to other track layouts, such, for example, as a stretch of single track connected at one end with another stretch of single track, but connected at the other end by a plurality of switches, with a stretch of multiple track.

Although I have here 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 combination, a switch section of railway track, a plurality of approach sections, a plurality of switches each adapted to form trafiic routes including one approach section or another and said switch section, a plurality of signals one for each approach section for governing the movement of traffic into said switch section, a normally deenergized control relay for each signal effective when energized to clear such signal, means for energizing each control relay when a train occupies the corresponding approach section provided no other signal control relay is energized, a directional relay for each control relay each governed in accordance with the condition of said switch section for preventing the energization of such control relay when the corresponding approach section is occupied by a train receding from said switch section, and means controlled in accordance with the position of said track switches for selectively controlling said directional relays.

2. In combination with a stretch of gauntlet rack and a stretch of double track, a switch connecting said gauntlet track with said double track and biased to a normal position for directing traffic movements from one track of said double track into the gauntlet stretch but operable to a reverse position either by a train moving from the other track of said double track into the gauntlet stretch or by manually operable means, a pair of signals one for each track of said double track for governing the movement of trafiic over said switch into said gauntlet stretch, means for clearing each of said signals when a train occupies a definite approach zone in rear of the corresponding signal provided the other signal is not clear, a normally deenergized switch indicating relay energized when the switch is moved to its reverse position, and directional means selectively responsive to the position of said switch indicating relay for preventing the clearing of each such signal when the approach zone therefor is cocupied by a train receding from said gauntlet stretch.

3. In combination with a stretch of gauntlet track between two stretches of double track, a first switch connecting one end of said gauntlet to one of said double track stretches and biased to a normal position but operable to a reverse position either by a trailing movement of trafiic or by manual means, a second switch connecting the other end of said gauntlet to the other double track section and biased to a normal position but operable to a reverse position either by a trailing movement of traffic or by manual means, a first pair of signals for governing the movement of trafilc into said gauntlet over said first switch, a second pair of signals for governing the movement of traffic into said gauntlet over said second switch, means for clearing each signal when a train occupies a definite approach zone in rear of the corresponding signal provided no other signal is clear, a directional relay for each signal for preventing the clearing of such signal when the corresponding approach zone is occupied by a train receding from said gauntlet, means controlled in accordance with the position of said first switch for selectively controlling the directional relays for said first pair of signals, and means controlled in accordance with the position of said second switch for selectively controlling the directional relays for said second pair of signals.

r sponsive 4. In' combination, a stretch of railway track including a first approach section and a second approach section, a switch section including a switch for connecting said first section or said second section with an adjacent single track section, a pair of signals one for each approach section for governing the movement of traffic from said first section and from said second section into said switch section, means for clearing the corresponding signal provided the other signal is not clear. effective when said first section or said second section is occupied and the switch section is unoccupied, and directionally controlled means governed in accordance with the condition of said switch section and the position of said switch for preventing the clearing of such signal when the first section or second section is occupied by a train receding from the switch section. 5. In combination, a main section of railway track, a switch for connecting said main section with or adjacent approach section when the switch is in a particular position, a signal for governing the movement of traific into said main section from said approach section, means retc the occupancy of said approach section for clearing said signal, a directional stick relay, a pick-up circuit for said relay closed when the main section is occupied and the switch is in such particular position, a stick circuit for said relay including its own front contact and a contact closed when the approach section is occupied, and means comprising a back contact of the directional stick relay for preventing said signal from clearing when said approach section becomes occupied.

6. In combination with two approach sections of railway track and a main section including a track circuit having a track relay, a switch connecting said main section with said approach sections, a contact operably governed by said switch closed if and only if said switch is in its reverse position, a normally deenergized stick relay, a pick-up circuit for said stick relay including said contact, a stick circuit for said stick relay including a back contact of said track relay, a pair of signals one for each approach section for governing the movement of traific from the corresponding approach section into said main section, and means including said switch stick relay for selectively controlling each of said signals in accordance with the position of said switch when a train receding from said main section occupies the corresponding approach section.

7. In combination with a main section of railway track including a track circuit having a track relay, a switch, an adjacent approach section including a track circuit having a track relay and connected with said main section when said switch is reversed, a signal for governing the movement of trafi'ic from said approach section into said main section, a normally deenergized switch indicating relay arranged to be energized when said switch is reversed, a normally deenergized directional stick relay, a pick-up circuit for said stick relay efiective for energizing said stick relay when a train is receding from said main section and including a front contact of said switch indicating relay and a back contact of the track relay for said main section, a stick circuit for said stick relay including a back contact of the track relay for said approach section, and means including said stick relay for controlling said signal.

8. In oombination with a main section of railway track including atrack circuit having a track relay, a switch, an adjacent approach's'ec tion including a track circuit having a track relay and connected with said main'section when said switch is normal, a signal for governing the 5 movement of traffic'from said approach section into said main section, a normally deenergized switch indicating relay arranged to be energized when said switch is reversed, a normally deener gized directional stick relay, a pick-up'circu'it for said stick relay effective for energizing said stick relay when atrain is receding from said main section and including a back contactof said switch indicating relay and a back contact of the track relay for said main section, a stick circuit for said stick relay including said back contact of the switch indicating relay and a back contact of the track relay for said approach section, and means including said stickrela'y for controlling said signal. 0

9. In combination with a stretch of railway track connected at one end by a first switch with a first approach section and at the other end by a second switch with a second approach section, a first and a second signal for governing the movement of name intdsa'id'stretch from said first section and from said second section, respectively, means for clearing the corresponding signal provided the other signal is not clear efiective when said first section or said second section is occupied and said stretch is unoccupied, directionally controlled means governed in accordance with the condition of said stretch and the position of said first switch for preventing the clearing of said first signal when the first section .55 is occupied by a train receding from the stretch, and directionally controlled means governed in accordance with the condition of said stretch and the position of said second switch for preventing the clearing of said second signal when the sec- 40 0nd section is occupied by a train receding from the stretch.

10. In combination with a stretch of railway track and a first and a second approach section,

a switch connecting said first and said second section to said stretch and biased to a normal position for directing traific movements from the first section into the stretch but operable to a reverse position either by a train moving from the second section into the stretch or by manually operable means, a first signal for governing traific movements from said first section into said stretch, a second signal for governing traffic movements from said second section into said stretch, a first control relay for said first signal, a second control relay for said second signal, a first normally deenergized stick relay, a second normally deenergized stick relay, means for energizing said first stick relay effective upon the occupancy of said stretch by a train receding from the stretch if said switch is in its normal position, means for energizing said second stick relay effective upon the occupancy of said stretch by a train receding from the stretch if said switch is in its reverse position, a circuit for said first control relay including a back contact of said first stick relay, and a circuit for said second control relay including a back contact of said second stick relay.

11. In combination, a railway track switch, an approach relay arranged to be deenergized if a train approaches said switch from the trailing direction but to be energized if the train approaches the switch from the opposite direction,

a normally deenergized stick relay, means for 6 selectively energizing said stick relay in accordance with the condition of said approach relay and in accordance with the condition of said switch, a signal for governing the movement of trafiic over said switch in the trailing direction, and means including a back contact of said stick relay for cleaning said signal if and only if a train in a particular zone is approaching said switch from such trailing direction.

12. In combination, a railway track switch having two positions, a pair of signals one for each position of said switch for governing the movement of traiiic over the switch in the trailing direction, an approach relay for each signal arranged to be deenergized if a train approaches said switch from the trailing direction but to be energized if a train approaches the switch from the opposite direction, a normally deenergized stick relay for each signal, means for selectively energizing such stick relay in accordance with the condition of the approach relay of the associated signal and in accordance with the position of said switch, and means including a back contact of such stick relay for clearing the associated signal if and only if a train in a particular approach zone is approaching said switch from such trailing direction provided the other signal is not clear.

l3.'In combination with a stretch of railway track including a track switch, a plurality of signals governing traffic into said stretch, a plurality of relays one for each signal, means for clearing each signal when the associated relay is energized, means for energizing each relay when a train occupies a definite approach zone in rear of the corresponding signal provided no other signal is clear, and means controlled by the track switch for preventing the energization of each such relay when the approach zone therefor is occupied by a train receding from said stretch. 14. In combination with a section of railway track containing a track switch and a signal governing trafi'ic over the switch, an indicating relay, a pick-up circuit for said relay closed when the switch assumes a particular position, a stick circuit for subsequently retaining said relay energized as long as said section is occupied, and means controlled by said relay for governing said signal.

- CHARLES W. BELL.

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