US1322316A - A corpora - Google Patents

Description

R. A. McCANN.

RAILWAY SIGNALING.

APPLICATION FILED SEPT-22, I915- RENEWED SEPT. 20, I917.

Patented Nov. 18, 1919 N I l 9 R k9 INVENTOR q N mxzaw UNITED STATES P TENT ornrcn RONALD A. vreoANN, or SWISSV'ALE,PENNSYLVANIA, ASSIGNOR TO THE UNION swrrcn & SIGNAL COMPANY, or s rssvALn, PENNSYLVANIA, A CORPORA- TION or PENNSYLVANIA.

RAILWAY" sIeNALINo.

Specification of Letters Patent.

Patented Nov. 18, 1919.

Application filed September 22, 1915, Serial No. 51,981. Renewed September 20, 1917. Serial No. 192,307.

To all whom it may concern:

Be it known that I, RONALD-A. MGQANN, a citizen of the United States,jres1d1ng at Swissvale, in the county of Allegheny and 7 track over which traffic moves in both directions, although it is not limited to this particular application.

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

In the accompanying drawings, Figure l is a diagrammatic view showing a stretch of single track with passing sidings and a plurality of signals for governing traffic through the stretch in both directions. Fig. 2 is a diagrammatic view showing one form and arrangement of ClI'CllltSffOl the control of signal 5 in Fig. l and embodying my invention.

Similar reference charactersrefer to similar parts in each of the views.

Referring first to Fig. 1, AI-I is a stretch of single track between two passing sidings M and 0 over which traflic moves in both directions. Adjacent the middle of stretch i --H is another passing siding N whereby stretch AH is divided into two blocks, AD and EH extending respectively from siding M to siding N and from siding N to siding O. Traflic through block H-E from east to west is governed by signals 1, 3 and 5, located at intervals through the block, and traflic through the. block from west to east is governed by othersignals 8, 6 and i. Traffic through block D-A is similarly governed by signals 9, 11 and 13 and by signals 16, 14 and 12. Signals 7 and 10 govern entrance into siding 'N from east and west respectively.

Ashere shown each s1gnal is of the three posltlon type,

inclined, and stop when the semaphore arm is horizontal. It is understood, however, that Iv do not limit myself to this particular kind of'signal.

Blocks AD and EH are divided by insulatedjoints 2 into several successive sections, AB, BC, C-D, and EF, FG, G H respectively, and as here shown a pair of opposing signals is located near each junction of adjacent sections, although I do not wish to be limited to this particular location of signals. The signals for block Al) are so controlled that when a train moving toward the east enters this block, slgnal 9 is placed at stop and is held there until the train passes out of the block, thus prohibiting a westbound train from entering the block while the eastbound train is anywhere in the block, As the eastbound train enters the block, it also causes signal 16 to indicate stop, and as it passes signals i l and 12 these signals are successively caused to change to stop indication. \Vhen the entire train passes out of section AB, signal 16 changes to the caution indication, and when the entire train passes outof section B-C, this signal returns to the full proceed indication. Signal 1% changes to caution when the train leaves section B-C, and to proceed when the train leaves section C-D. Two or more trains may, therefore, follow each other through the block under the same signal protection as is customarily provided on double track roads. Similarly, when a westbound train enters'block AD, signals 9, 12, 1i and 16 United States, Nos. 1201 998 and 1233et88, granted to me on Nov. 14;, 1916, and on July 17, 1917, respectively. I do not wish to be limited, however to any particular arrangements of apparatus and circuits for accomplishing this signal operation.

Whenever signal 9 indicates stop, signal 7 indicates caution, and whenever signal 7 indicates stop, signal 5 indicates caution. The manner in which this control is accomplished will be explained hereinafter. It is desirable, however, that when an east-bound train occupies block A-D, signal 5 as well 'as signal 7 should indicate caution, but that when a westbound train has passed signal 9, thus allowing signal '7 to change to caution, signal 5 should return to the full proceed position. The reason for this is as follows: Assume that signal 5 indicates proceed while signal 9 is at stop, and that two trains moving in opposite directions approach siding N. If the eastbound train should pass signal 9 just after the westbound train had passed signal (indicating proceed), the westbound train would receive a stop indication at signal 7 without having been previously warned by a caution indication at signal 5. However, if two westbound trains are movin along the track from H to A, it is desirable that signal 5 should change to proceed indication as soon as the first train has passed signal 9, in order to avoid any unnecessary delay to the second train by a caution indication at signal 5.

The object of the present invention is the provision of novel and simple means'for accomplishing the desired control of signal 5.

Referring now to Fig. 2, track section DE is provided with a track circuit comprising a battery 6, the track rails and a track relay T Track section EF is divided into two sub-sections E L and LF, which sub-sections are provided with track circuits comprising track relays T and T respectively. The track section to the left of location D is provided with a track circuit which includes a track relay T Adjacent signal 7 are located a signal relay R a polarized relay P and an auxiliary relay X for purposes to be pointed out hereinafter. Each relay R and P is so constructed that when the polar contacts have been shifted to one extreme position by current of one polarity, they remain in such position, even after the relay is de'e'nergized, until the relay becomes energized by current of the opposite polarity. Signal 7 is provided with a pole changer and a circuit controller V which has three contacts m a and 0. Contact m is closed at both proceed and caution indications of signal 7 and also while th semaphore bladeis moving between these two indications; contact n,

is closed only whil the semaphore is be tween the caution and stop indications; and contact 0 is closed only when the signal is indicating caution.

Relay R is controlled by pole changer TV" of signal 9 and by track relay T the circuit being: from battery Z, through wire 70, pole changer W", wire 71, contact 72 of relay T wire 73, relay R", wire 74, pole changer N and wire 75 to battery Z When signal 9 is indicating proceed circuit controller W is in the position shown,

and relay R is energized by current of normal polarity, so that it closes polarized contacts 76 and 77.

Relay X is controlled by relay R and contact m of controller V the circuit being: from the positive terminal of battery Z through wire 81, contact m of controller V wire 80, contact 76 of relay R relay X wires 79 and 78 to the negative terminal of battery Z.

The caution indication of signal 7 'is con trolled by relay R through the following circuit: from battery Z through wires 81 and 88, front contact 87 of relay R wires 86 and 85, operating mechanism of signal 7, wire 84, front contact 83 of relay R", wires 82 and 78 to battery Z The proceed indication of signal 7 is controlled jointly by relays R and X, the circuit being the same as the caution indication circuit up to and including wire 86, then through wire 91, contact 90 of relayv X wire 89, operating mechanism of signal 7, wire 84, front contact 83 of relay R wires 82 and 78 to battery Z Relay R and "controller V enter into the control of relay P The contacts of this relay are operated to the normal position (in which they are shown on the drawing) by current flowing in the circuit: from the positive terminal of battery Z through wires 81 and 96, contact 0 of controller V, wire 95, front contact 94 of relay R contact 77 of relay R wire 93, relay P wire 92 to the middle terminal of battery Z 1. The contacts of relay 1? are reversed by current through the circuit: from the middle point of battery Z through wire 92, relay P wire 93, contact 77 of relay R lower con tact 94E of relay R wire 97, contact a of controller V wire 78 to the negative terminal of battery Z Relay R is controlled by the track relays of section EF, by relay P andaccording as relay P is normal or reversedby relay X or pole changer W With the ap paratus in the positions shown in the drawing, relay R is energized by current in the circuit: from the positive terminal of bat tery Z through wires 81 and 101, front con tact 102 of relay X wire 106, contact 107 of relay P, wire 104C, contact 109 of relay T wire 113, contact 110 of relay T wire 111, energizing winding of relay R wire 112, contact 108 of relay P wire 114:, front contact 103 ol'relay X wires 115 and 78 to the negative terminal of battery Z lVhen relay X is deenergized so that its contact fingers 102 and 103 engage their respective back contacts, the current in this circuit is reversed (as evident from the drawing) so that relay R opens contact 23. hen relay P is reversed the circuit for relay R is as follows: from the positive terminal of battery Z through wires 81 and 116, pole changer wire 117, contact 107 of relay P wire 104., contact 109 of relay T wire 113, contact 110 of relay T wire 111, relay R wire 112, contact 108 of relay I, wire 118, pole changer W, wires 119 and 78 to the negative terminal of battery Z. The direction of current in this circuit is con trolled by pole changer in the same way as the direction of current in the first described circuit for relay R is controlled by relay X Signal 5 is controlled by relay B through the medium of circuits which are obvious from the drawing, and the same thing is true as to the control of signal 9 by relay B. To explain the operation of this system of signaling, suppose that a car or'train travels from'F to D. As the t'ain enters section F-L it deenergizes relay T, which opens at contact 110 the circuit for relay B, so that signal 5 is Put to the stop indication. When the train enters section L-E it deenergizes relay T which causes at contact 109 another break in the circuit for relay B, so that relay R remains deenergized even when the train leaves section L-F and causes relay T to close its front contacts. When the train enters section E-D, track relay T is deenergized and opens the circuit for relay R which in turn opens at contact 83 and 87 both the proceed and caution indication circuits of signal 7, so that this signal moves to the stop indication. Relay P is reversed during this movement of the signal because back contact 9 1 of relay R s closed, so that the reverse energization circuit for relay 1? is momentarily completed as a finger of circuit controller V sweeps over segment at. Relay P accordingly re verses its contacts 107 and 108 so that the control circuit of relay R is led through.

that signalt 'is caused to-indicate caution. hen the train enters the track section governed by signal 9, it causes signal 9 to indicate stop by opening track relay T Sig nal 9 reverses pole changer so that, when the train leaves section DE completely and causes relay T to close at cont-act 72 the circuit for relay R the latter relay is energized in the reverse direction. Consequently, signal 7 moves to the caution indication and changes pole changer 1V to normal. The direction of flow of current in relay R is thus changed tonOrmal, so that contact 23' is closed and signal 5 is caused to indicate proceed. hen the train passes out of the section governed by signal 9, this signal assumes the caution indication and changes pole changer 1V to normal. Current then flows through relay R in the normal direction so that it closes at contact the circuit for relay X This relay closes its front contacts 90, 102 and 103. Contact 90 closes the proceed indication circuit of signal 7 However, before the signal actually moves from the caution position, relay P has been brought back to the normal position shown in Fig. 3 by current in its normal energization circuit, which is closed at contact 0 of controller V and contact's 9a; and 77 of relay R The contacts of relay P are thus returned to the normal position shown in Fig. 3, so that the circuit of relay R is transferred from pole changer 1V to contacts 102 and 103 of relay X Relay X" being energized, the current continues to flow through the circuit of relay in normal direction so that signal 5 'remains unaffected. lVhen signal 7 leaves its caution position it opens at contact 0 of con troller the circuit for relay P This relay remains in the normal position even though decnergized, as pointed out hereinbefore. The circuit for relay X remains unbroken when signal 7 moves to the pro-' ceed aspect because its circuit is closed through contact m.

A train movement in the reverse direction, 2'. c. from west to east causes the :tollowing operation of the apparatus. As soon as the train enters block A-D (Fi 1) from siding M, it causes opposing signals 13, 11 and 0 to assume the stop indication. As signal. 9 changes its indication, pole changer reverses the current through relay R Reversal of current causes this relay to drop its neutral contact fingers, then reverse'its polar contact fingers and finally pick-up its neutral contact fingers. The opening of the front contacts 87 and 83 of relay R opens the holding circuit for signal 7, so that this signal begins to change its indication. The opening of front con tact 94 of relay R opens the circuit of relay P However, this has no eli'ect on the latbecause the circuit of which this contact is a member, is open at contact a of controller V For similar reasons the opening of polarized contact 77 of relay R has no effect on relay P The opening of polarized contact 76 of relay R breaks the circuit of relay X so that its contacts drop causing results which 1 shall explain below. When the neutral front contacts of relay R are M .in closed they complete at contacts 87 a1d83 the caution circuit for signal 7, so that this signal is arrested as it rea hes the caution position. The'closure of front contact 9% of relay R again has no efi'ect on relay P because this circuit is open at polarized contact 77. Relay X is now decnergized, as mentioned above, so that contacts 102 and 103 have reversed the current in the circuit for relay R Polarized contact 23 of relay E is, therefore, reversed so that signal 5 goes to the caution indication. To summarize, the entrance of a train into block AD from siding M (Fig. 1) causes not only a stop indication ofthe 0pposing signals 13, 11 and 9 of block AD, but also a caution indication of signals 7 and 5 which govern the entrance into siding N from the opposite direction. If there were a west-bound train in block E-H, the engineer of that train would thus be duly warned at signal of the approach of the cast-bound train to siding N. The engineer of the eastbound train would receive a similar warning by finding signals 12 and 10 at cautiondue to a similar operation of apparatus which would have been caused by the entrance of the west-bound train into block E T. The engineers of the trains would thus be prepared to pass each other at siding N in accordance with the rules and regulations of the railroad. If the east-bound train were the superior train it would be allowed to remain on the straight track within siding limits, whereas the west-.boundtrain or inferior train would be switched off to the siding track.

rlrssuming that the east-bound train has reached the entrance to siding N, it causes the following operation of the signal apparatus as it passes through the siding limits: Track relay T is deenergized as the train enters section DE, so that signal 10 (which is controlled similarly to signal 7) is deenergized and assumes the stop indication. Relay T opens at contact 72 the circuit for relay R, which therefore opens its front contacts and closes its back contacts. Of course, the polarized contacts 76 and 77 of relay R remain open. The opening of front contacts 87 and S3 of relay R breaks the holding circuit for signal 7 so that the signal moves to the stop indication. Closure of back contact 9 1 of relay R has no effect on relay P because its circuit is open at contact 7 7 of relay B". As the rear end of the train leaves section CD all signals in block A-D assume the proceed indication (provided there is no other train in the block). As signal 9 resumes its proceed aspect it changes pole changer lV back to its normal position. Although this changes to normal the polarity of the connection of battery Z to the line circuit of relay R this relay is not affected thereby until the train has completely left section Dll, because its circuit is open at relay T As the train enters section E-L it deenergizes track relay T so that signal 8 changes to the stop indication. Track relay T opens at contact 109 the circuit for relay B so that signal 5 is caused to indicate stop. By means of the control hereinbefore referred to, signals 3 and 1 of block EH (Fig. 1) also assume the stop indication. When the rear end of the train leaves section D E, relay T is re'e'nergized and closes at contact Z2 the circuit for relay R so that current of normal polarity is sent through the relay winding. This causes successively the closure of the polarized contacts and the neutral front contacts. Contact 76 of relay R closes the circuit for relay X but this relay is not energized because its circuit is open for the time being at contact on of controller V Neither does the closure of contact 77 have any effect on relay P because during the fractional time interval before neutral back contact 9 1- of relay R" opens, the reverse circuit of relay P is open at contact 77,, and when front contact 94 of relay R is closed, the normal circuit of relay P is open at contact 0. Closure of front contacts 87 and 83 of relay R closes the caution indication circuit of signal 7 so that signal 7 moves to the caution position. During this movement, signal 7 changes pole changer V. to normal. This is irrelevant, however, to the operation of other apparatus because pole changer W is disconnected at the contacts of relay 1 from the circuit of relay R As soon as the signal reaches the caution position, contact m of controller V completes the circuit of relay X so that this relay opens its back and closes its front contacts. Closure of contact 90 of relay X completes the proceed indication circuit of signal 7, so that it moves to the proceed indication. Contacts 102 and 103 change to normal the connections of battery Z to the control circuit of relay R so that this relay will be energized by current of normal polarity when its circuit is closed later 011 at track relay T Thus all apparatus located adjacent signal 7 has been returned to the position shown in the drawin Althou h I have in Fi 2 shown ones ecific arrangement of apparatus and circuits for accomplishing the desired control of the signals, it is understood that my invention is not limited to this specific arrangement, but that it may be applied to any arrangement of apparatus and circuits for ac complishing this same control of the circuits.

Where in the accompanying Claims I have used the expression three sections, or three successive sections, the sections referred to are sections EF, D'E and 0-D, these being the first, second and third sections respectively. The signals referred to in the claims for these sections are signals 5, 7 and 9.

Although I have herein shown and described only one form of railway signaling system 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 stretch of railway track comprising three successive sections, a signal for the first section, means for-governing said signal, said means comprising means responsive to the presence or absence of a car or train in the second section, means responsive to the presence or absence of a train in the third section, and means responsive to the direction of the passage of a train through the stretch for selecting between the two last mentioned means.

2. In combination three successive sections of a railway track, a track relay for each section, a signal for the first section, means controlled by the track relay of the third section and adapted to control said signal, means controlled by the track relay of the second section and adapted to control said signal, and means controlled by said track relays for selecting between said means adapted to control said signal.

3. In combination, three successive sections of a railway track, a signal for the first section, a track relay for each section, means for the second section and means for the third section governed by said track relays for .at times controlling said signal, and a device controlled by said track relays for selecting between said means.

4. In combination, a stretch of railway track comprising three successive sections, track relays for the second .and third sections, a signalfor the first section, means controlled by one track relay for controlling the signal, means controlled by the other track relay for controlling the signal, and means controlled by said track relays for selecting between said means for controlling the signal.

signal.

responsive to reversals of current and controlled by said track relaysfor selecting between said means adapted to control said signal. a

6. In combination, an advance section and a rear section of railway track, a track relay for each section, a signal, means governed .by the track relay of the advance section adapted to control said signal, means governed by the track relays of both sections adapted to control said signal, and means controlled by said track relays for selecting between said means adapted to control said signal.

7. A stretch of railway track comprising an advance and a rear section, atrack relay for each section, a relay comprising neutral and polarized armatures responsive respectively to the track relays of the rear and advance sections, a signal, means controlled by said neutral armature for at times controlling said signal, means controlled by bothof said armatures for at times control ling said signal, and means responsive to the direction of trailio through said stretch for selecting between said means for controlling said signal.

8. In combination, a stretch of railway track,- three successive signals, 5, 7, and 9, track circuits including track relays for the control of said signals, a pole-changer controlled by signal 9, a 1: ole-changercontrolled by signal 7, and means controlled by said track relays in accordance with the sequence in whichthey are operated for controlling signal 5 by one-or the other of said polechangers. e

e 9. In combination, a stretch of track comprising three sections, a track relay for each section, a signal located at the entrance to each section, means for governing the third signal by the track relay of the third section, means for governing the second signal by the third signal and the track relay of the second section, means for governing the first signal by the second signal and the track relay'of the third section, and means responsive to reversals of current-for at times changing the control, of said first signal. from the second signal tothe third 10. In combination, a stretch of railway track comprising three sect1ons,a signal'located adjacent theentrance to each section,

a track relay for each section, means for controlling the third signal by the track relay of the third section, a polarized relay comprising a neutral and a polarized armature,

means "for controlling the second signal by the polarized relay, an auxiliary relay controlled bv the polarized relav and by the second signal, a translating device responsive to reversals of current, means for controlling said device by the polarized relay and the second signal, a circuit for the first signal controlled b said first track relay, and means controlled by said device for controlling said circuit either by said second signal or by said auxlliary relay.

11. In combination, a stretch of railway track, two successive signals governing trafiic thereover, a relay responsive to reversals of current for controlling the first signal, said first signal indicating clea or caution according as said relay is normally or reversely energized, and means controlled by a train passing over said stretch for causing said relay to be normally or reversely energized when the second signal indicates caution according as said train is moving in the direction governed by said signals or in the opposite direction.

12. In combination, a stretch of railway track, two signals governing trafiic thereover in one direction, a polarized relay for controlling the first of said signals whereby said signal indicates clear or caution according as said relay is energized in normal or reverse direction, and means controlled by a train passing along said stretch for causing said relay to be positively energized when the second signal indicates caution and the train is moving in the direction governed by said signals, and for causing said relay to be reversely energized when the second signal indicates caution and the train is moving in the opposite direction.

13. In combination, a stretch of railway track divided into three successive sections, a signal for the first section arranged to indicate stop, caution and proceed, said signal indicating proceed when not affected by the presence of trains, means controlled by a train in the third section for causing said signal to indicate caution, and train-controlled means operated by a train entering the second section moving toward the third for removing said signal from control by a train in the third section whereby when the latter train occupies the third section said signal may indicate proceed. V

14. In combination, a stretch of railway track divided into three successive sections, a signal for the first section arranged to indicate stop, caution and proceed, said sig nal indicating proceed when not afi'ected by the presence of trains, means controlled by a train in the third section "for causing said signal to indicate caution, and train-controlled means set in operative condition by a train entering the second section moving toward the third and maintained in such condition until the train leaves the third section for removing said signal from control by a train in the third section whereby when the train occupies the third section the signal may indicate proceed.

15. In combination, a stretch of track divided into three successive sections, a signal for the first section, a caution indication circuit and a proceed indication circuit for said signal, the latter circuit being closed when the signal is not affected by the presence of trains, means controlled by a train in the third section for opening the proceed circuit and closing or holding closed the caution circuit, and means controlled by a train entering the second section moving toward the third for removing said proceed circuit from control by said first-mentioned means whereby when the latter train occu pies the third section the signal may indicate proceed.

16. In combination, a stretch of railway track comprising three sections, a first and a second signal for the first and second oi said sections respectively, a first and a second signal relay each reponsive to reversals of current for controlling said first and second signals respectively whereby each sig nal indicates proceed or caution according as the corresponding relay is energized in normal or reverse direction, train-controlled means for causing the second signal relay to be energized in reverse or normal direction according to the presence or absence of a train in the third section, a pole-changing relay for at times controlling the first signal relay so thatsuch signal relay is energized in normal or reverse direction according as the pole-changing relay is energized or deener'gized, a pole-changer operated by the second signal for at other times controlling the firstsignal relay so that such signal relay is energized in normal or reverse direction according as the second signal indicates caution or stop, means controlled by the second signal relay for energizing the pole-changing relay when the second signal relay is ener gized in normal direction but not when it is energized in reverse direction, a directional relay for connecting said first signal relay with said pole-changing relay or with said pole-changer according as the contacts of the directional relay are in normal or reverse position, and means controlled by said second signal relay for energizing said directional relay in such direction that its contacts assume the reverse position when a train moving in the direction in which said signals govern trafiic enters the second section, and for energizing the directional a second signal for the first and second of said sections respectively, a first and a second signal relay each responsive to reversals of current for controlling said first. and second signals respectively whereby each signal indicates proceed or caution according as the corresponding relay is energized in normal or reverse direction, train controlled means for causing the second signal relay to be energized in reverse or normal direction according to the presence or absence of a train in the third section, a pole-changing relay for at times controlling the first signal relay so that such signal re lay is energized in normal or reverse direction according as the pole-changing relay is energized or deenergized, a pole-changer operated by the second signal for at other times controlling the first signal relay so that such signal relay is energized in normal or reverse direction according as the second signal indicates caution or stop, means controlled by the second signal relay for energizing the pole-changing relay when the second signal relay is energized in normal direction but not when it is energized in reverse direction, and means controlled by a train passing through said sections in the direction in which said signals govern tratfic for controlling said first signal relay with the pole-changer when the train enters the second section and with the pole-changing relay when such train leaves the third sec tion, said first signal relay remaining connected with the pole-changing relay during the passage of a train in the opposite direction through said sections.

18. In combination, a stretch of railway track comprising three sections, a first and a second signal for the first and second of said sections respectively, a first and a second signal relay each responsive to reversals of current for controlling said first and second signals respectively whereby each signal indicates proceed or caution according as the corresponding relay is energized in normal or reverse direction, train controlled means for causing the second signal relay to be energized in reverse or normal direction according to the presence or absence of a train in thevthird section, a pole-changing relay for at times controlling the first signal relay so that such signal relay is energized in normal or reverse direction according as the pole-changing relay is energized or deenergized, a pole-changer operated by the second signal for at other times controlling the first signal relay so that such signal relay is energized in normal or reverse direction according as the second signal indicates caution or stop, means controlled by the second signal relay for energizig the pole-changing relay when the second signal relay is energized in normal direction but not when it is energized in reverse direction, and train governed means for causing said first signal relay to be controlled by said pole-changer or by said pole-changing relay according as a train is moving in the direction in which said signals govern trafiic .or in the opposite direction.

19. In combination, a stretch of railway track divided into three successive sections, a signal for the first section adapted to indicate stop, caution and proceed, a second signal for the second section, a line relay responsive to reversals of current for con" trolling said second signal, train controlled means for deenergizing said line relay when a train occupies said second section and for energizing said line relay in normal or reverse direction according as the third section is free or occupied, means controlled by said line relay for causing said signal for the first section to indicate proceed or caution according as the relay is energized in normal or reverse direction, and means con-p trolled by said line relay when deenergized by a train entering the second section moving toward the third section for removing said signal from control by said relay to the extent that the signal may subsequently indicate proceed when the relay becomes reversely energized due to the passage of such train into the third section.

20. In combination, a stretch of railway track divided into three successive sections, a signal for the first section adapted to indicate stop, caution and proceed, a relay responsive to reversals of current, train controlled means for deenergizing said relay when a train occupies the second section and for energizing said relay in normal or re verse direction according as the third section is free or occupied, means controlled by said relay for causing said signal to indicate proceed or caution according as the relay is energized in normal or reverse direction, and means controlled by said line relay when deenergized by a train entering the second sec tion moving toward the third for removing said signal from control by said relay to the extent that the signal may subsequently indicate proceed when the relay becomes reversely energized due to the passage of the train into the third section.

21. In combination, a stretch of railway track divided into three successive sections, a signal for the first section adapted to indicate stop, caution and proceed, a relay responsive to reversals of current, train controlled means for deenergizingsaid relay when a train occupies the second section and for energizing said relay in normal or reverse direction according as the third sec tion is free or occupied, means controlled by said relay for causing said signal to indicate proceed or caution according as the relay is energized in normal or reverse direction, an auxiliary relay for removing said signal from control by said first relay to the extent that the signal may indicate proceed when the first relay 1s energized in reverse direction, and means controlled by said first relay for actuating said auxiliary to exercise its said control When the first relay is deenergized by a train entering the second section moving toward the third, and for restoring said auxiliary to its original condition when the first relay becomes energized in normal direction due to the passage of the latter 10 train out of the third section.

In testimony whereof I afix my signature in presence of tWo Witnesses.

RONALD A. MOCANN.

Witnesses A. G. Nouns, P. F. WILLARD.

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