US2107680A - Railway signaling - Google Patents

Description

Feb. 8,1938. I p CRAGQ 2,107,680

RAILWAY S IGNALING Filed Sept. 1a, 1936 5 Sheets-Sheet 1 a (Y T n k I E N Ew TN gs; F

' INVENTOR fi PaulH. ago. BY

HIS ATTORNEY Feb. 8, 1938 P. H. CRAGO RAILWAY SIGNALING Filed Sept. 18, 1936 3 Sheets-Sheet 2 INVENTOR Paul raga.

HIS ATTORNEY hm kg m P. H. CRAGO RAILWAY SIGNALING Filed Sept. 18, 1936 Feb. s, 1938.

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INVENTOR Paul [I H16 ATTORNEY Patented Feb. 8, 1938 UNITED STATES PATENT OFFICE RAILWAY SIGNALING Application September 18, 1936, Serial No. 101,469

12 Claims.

My invention relates to railway signaling, and particularly to signaling involving wayside signals located along a trackway for governing the passage of trains.

A feature of my invention is the provision of novel and improved apparatus for establishing a distinctive control for each of three sections in the rear of an occupied section. Each distinctive control is effective to cause a corresponding aspect of the associated wayside signal whereby there is produced a three-block, fourindication, system of signaling.

The present invention is an improvement on the apparatus disclosed and claimed in an application, Serial No. 101,467, for Letters Patent of the United States, filed September 18, 1936, by Howard A. Thompson, for Railway signaling, as well as on the apparatus disclosed and claimed in an application, Serial No. 101,468, for Letters Patent of the United States, filed September 18, 1936, by Ralph R. Kemmerer, for Railway sign'aling.

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

In the accompanying drawings, Figs. 1A and 1B are diagrammatic views which when placed end to end in the order named illustrate one form of apparatus embodying my invention. Fig. 2 is a diagrammatic view illustrating a modification of a portion of the apparatus shown in Fig. 1A and also embodying my invention.

Similar reference characters refer to similar parts in each of the several views.

Referring to the drawings, the reference characters l and 8 designate the rails of a stretch of railway track along which traffic normally moves in the direction indicated by the arrows. These rails are divided by insulated joints 9 into a plurality of track sections W-X, X.Y, and YZ.

As here shown, each track section is divided by insulated joints 9 into at least two subsections IT, 2T, 3T, 4T, etc. Each subsection is provided with a track circuit which includes a track battery l connected across the rails at one end of the subsection and a track relay, designated by the reference character TR with a prefix the same as the numerical prefix in the reference character of the associated subsection, connected across the rails at the other end of the subsection.

To govern the passage of trains through the stretch of railway, a wayside signal, designated by a suitable distinguishing reference character, is provided for each track section. Each of these signals includes an upper unit U and a lower unit L. These units may take any one of several forms of signal mechanism such as semaphore, color light, searchlight, or position light. As here shown, each upper unit U is a semaphore 5 arm capable of assuming a horizontal or stop position, a 45 or caution position, and a vertical or proceed position; and each lower unit L is a caution lamp Y capable of displaying a yellow light.

Operatively connected with each semaphore arm U are contacts l1, l8, I9, 20, 2|, and 22. Contact H is in engagement with contact 23 whenever the semaphore arm U is in the 30 position or the 89 position or at any point between these positions. Contacts [8, l9, and 2! are in engagement with contacts 24, 25, and 26, respectively, whenever the semaphore arm is in its 60 position or in its vertical position or at any point between these two positions, and are in engagement with contacts 21, 28, and 29, respectively, whenever the semaphore arm is at any point below the 60 position. Contact is in engagement with contact whenever the semaphore arm is in its 60 or in its vertical position or at any point between these two positions. Contact 22 is in engagement with contact 3| whenever the semaphore arm is in its 43 position or in its vertical position or at any point between these two positions and is in engagement with contact 32 whenever the semaphore arm is below the 43 position.

Each semaphore arm U is provided with a lamp E which when lighted provides supplementary color light indications corresponding to the positions of the associated semaphore arm.

For controlling the associated signal, each section is provided with a polarized signal control relay, a neutral signal control relay, and an auxiliary relay designated by the reference charac- 40 ters DR, HR, and DP, respectively, each with a prefix the same as the reference character of the associated signal.

For controlling the associated relays DR and HR, each section is provided with a pair of conductors each of which extends to the signal next in advance and each of which includes a front contact of each of the associated track relays.

Each section is provided with an operating battery the terminals of which are designated by the reference characters B0 and CO and each section is provided with a line battery designated by the reference character H. Each line battery II is provided with a low voltage positive terminal, a high voltage positive terminal, and

a common return terminal designated by the reference characters Bl, B2, and C, respectively.

Each relay DR is connected to the associated pair of conductors by signal contact l'l-23 of the associated signal. Each relay HR is connected to the associated pair of conductors through a back contact l6 of the associated relay DP and contact l82l of the associated signal. Each relay DP is governed by the associated relay DR. For example, relay i213? is governed by a circuit which includes front contact 34 of relay EZDR, so that relay iZDP will be energized or deenergized when relay lZDR is energized or deenergized. As will be explained more in detail hereinafter, the pair of conductors for each section is at times supplied with energyv of a relatively low value and at other times is supplied with energy of a relatively high value. The pickup value of the relays HR is such that these relays will become picked up upon receiving energy of either value whereas the pickup value of the relays DR is such that these relays will become picked up only upon receiving energy of the higher value.

The signal contacts 26, 2i, and 22 and the relays HR and DP control the magnitude and direction of the energy supplied to the line conductors for the section next in the rear.

For controlling the signal lamps E and Y, each section is provided with an approach lighting relay designated by the reference character ER with a prefix the same as the reference character of the associated signal. The relays ER are connected in series with the line conductors for the section next in rear and therefore are energized at all times except when that line circuit is open. That is, the approach lighting relays ER become released to energize the associated lamp E and the control circuit for the associated lamp Y only when the section immediately to the rear of the signalwith which such lamps are associated becomes occupied by a train.

The relays HR, DR, and DP control the upper unit U and the lower unit L of the associated signal in the following manner: When all relays are deenergized (see signal 15), both semaphore arm U and lamp Y are deenergize-d so that signal i5 is displaying its semaphore arm in the horizontal position to indicate stop. When only the relay HR is energized (see signal I 4), a caution circuit for the semaphore arm U of that signal is closed over a path which passes from terminal BO over front contact 35 of relay MHR, semaphore arm U, and contact l928 of signal I4 to terminal CO. Semaphore arm U of signal l4 therefore is in the caution position to indicate approach next signal prepared to stop. When relay DR is energized in the reverse direction (see signal 2 3) relay l BDP is energized over front contact 34 of relay itDR so that relay l3HR becomes deenergized and so that another caution circuit for semaphore arm U is closed over front contact 36 of relay i 3DP. A circuit also is established for the lamp Y of the low-er unit L of that signal. This circuit passes from terminal BO over front point of contact 3% of relay l3DP, front point of contact 31 of relay ISDR, reverse polar contact 38-39 of relay itDR, lamp Y, and back contact 4| of relay ISER to terminal CO. Signal l3, therefore, is displaying its upper semaphore arm U in the caution position and a circuit for lamp Y is established so that when relay i3ER becomes released by a train approaching signal I3 in section W-X, this signal will display its semaphore arm in the caution position over a yellow light to indicate approach next signal at medium speed. When relay DR becomes energized in the normal direction (see signal l2 and assume for the moment that its semaphore arm U is in the caution position), relay IZDP will also be energized so that the caution circuit for the upper semaphore arm U will remain closed over front contact 36 of relay DP, and a proceed circuit for the semaphore arm U will be closed over a path which passes from terminal BO over front contact 36 of relay IZDP, front point of contact 42 of relay IZDR, normal polar contact 38-50 of relay IZDR, semaphore arm U, and contact l9-28 of signal IE to terminal CO. When the semaphore arm U reaches its 60 position, contact Iii-28 will become opened and contact l925 will become closed so that the proceed circuit will then include the front point of contact 43 of relay lZDP. Signal I! will, therefore, display its semaphore arm in the vertical position, as shown in the drawings, to indicate proceed at normal speed. When the semaphore arm U of signal l2 attained its proceed position, signal contact |'l23 became opened so that relay IZDR and consequently relay l2DP are both released. The caution and clear circuits for upper semaphore arm U, therefore, are disconnected from the terminals B and C0 of the operating battery and are connected directly to the line conductors for the section W-X. The path connecting the proceed circuit to the line conductors for section W-X includes back point of contact 42 of relay lZDR, back point of contact 46 of relay IQHR, back point of contact 35 of relay IZDP, signal contact Iii-24, as well as back point of contact 43 of relay EZDP and signal contact l9-25.

As here shown, a train K is indicated diagrammatically in the section immediately to the right of location Z so that the signal l and associated relays are all deenergized.

When signal l5 and associated apparatus is in this condition, relay HlI-IR is energized in the reverse direction by energy of a relatively low value over a path which passes from terminal Bi of battery l at signal l5, through signal contact 22-32 of signal l5, front contact 45 of relay GTR, front contact d6 of relay STR, relay MHR, back contact it of relay MDP, contact |8 -21 of signal I4, front contact 41 of relay ETR, front contact 48 of relay fiTR, back point of contact 49 of relay I5DP, signal contact Zl-ZQ of signal l5, and relay ISER to terminal 0.

When relay l iI-IR is energized so that semaphore arm U of signal i4 is in the caution position, relay I3DR is energized in the reverse direction by energy of relatively high value over a path which passes from terminal B2 of battery I! at signal l5, through front contact 56 of relay MHR, back point of contact 5! of relay lDP, contact 223i of signal M, front contact 52 of relay 4TB, front contact 53 of relay BTR, relay l BDR, contact l1-23 of signal l3, front contact 54 of relay 3TR, front contact 55 of relay 4TH, back point of contact 56 of relay MDP, contact 2l29 of signal l4, and relay MER to terminal C.

When relay l3DR is energized in the reverse direction, semaphore arm U remains in its caution positiomrelay IBDP becomes energized and relay IEHR becomes deenergized. When signal 13 and associated apparatus is in this condition and assuming for the moment that semaphore arm U of signal I2 is in the caution position, relay IZDR will be energized in the normal direction by energy of relatively high value over a path which passes from terminal 132 of battery Il'at signal [3, through front point of contact 51 of relay I3DP, front contact 58 of relay 2TB, front contact 59 of relay I'I'R, contact Il-23 of signal 12, relay IZDR, front contact 6i) of relay ITR, front contact iii of relay 2TB, contact 22--3l of signal l3, front point of contact 62 of relay I3DP, and relay HER to terminal C.

As a result semaphore arm U of signal I2 is caused to assume the proceed position, so that the line conductors for the section next in rear of location W are supplied with energy of the high value in the normal direction over contacts 2ii-3B, 223I, and 2l-26 of signal l2. Consequently, the signal (not shown) associated with such conductors in the rear Will be in position to display the normal proceed indication.

Summing up then for the system illustrated in Figs. 1A and 13, it will be seen that, when a block is occupied by a train, the signal for that block will display its semaphore arm in the horizontal position to indicate stop; the signal for the section first in rear of such occupied section will display its semaphore arm in the 45 position to indicate approach next signal prepared to stop; the signal for the section second in rear of such occupied section Will display its semaphore arm in the 45 position over a yellow light to indicate approach next signal at medium speed; and the signal for the section third in rear of such occupied section will display its semaphore arm in the vertical position to indicate proceed at normal speed.

The relays DP are provided with a slow releasing characteristic so that the caution circuit for the associated semaphore arm U will remain closed and so that the energization of the line conductors to the rear will not be disturbed during pole changing periods. For example, when the train K vacates the section to the right of the location Z so that the energization of relay I3DR is changed from the reverse direction to the normal direction to cause signal is to display the normal proceed indication, front contact 34 of relay i3DR will become momentarily opened. Due to the slow release characteristic of relay ISDP, however, front points of contacts 36, 51, and 62 of this relay remain closed so that the energization of the circuits controlled by these contacts will not be disturbed during this period.

The relays HR are provided with a slow release characteristic so that both the caution circuit for the associated semaphore arm U and the circuit for the line conductors in the rear will remain closed during the open circuit periods when contact 22 forthe signal in advance is moving from contact 32 to contact 3!. For example, when the train K vacates the section to the right of location Z so that relay I5HR becomes energized to cause semaphore arm U of signal 15 to assume the 45 position to indicate approach next signal prepared to stop, contact 22 will become disengaged from contact 32 and will become engaged to contact 3! to supply energy of high value to relay liiDR. Due to the slow release characteristic of relay Nil-IR, however, front point of contact 35 and front contact of this relay will remain closed during the time that contact 22 is in engagement with neither contact 32 nor 3| so that the energization of the circuits controlled by these contacts will not be disturbed during such open circuit periods.

When the energization'of the line conductors is changed from the high value to the low value to provide a more restrictive indication, such line conductors are momentarily disconnected from the source of energy so that the associated relay DR will be certain to release. For example, if the section Y--Z becomes occupied by the train K so that the energization of the line conductors for the section X-Y is changed from the high value to the low value, front contact 50 of relay [4BR will become opened to disconnect energy from the line conductors for the section X--Y and such line conductors will remain deenergized until such time as the semaphore arm U of signal l4 drops below its 43 position Under this condition, that is, with section Y-Z occupied either by a train making a reverse move or by a train entering section Y-Z from a spur track (not shown), relay I3DR will become released so that the circuit for the caution lamp Y of signal l3 cannot be established. A short time thereafter, relay ltDP will become released so that relay [3H3 will become energized over the line conductors for section X-Y to maintain the energization of the caution circuit for semaphore arm U of signal i3. Upon the releasing of relay I3DP and the picking up of relay I3HR, the line conductors for section W-X will be supplied With energy of high value in the reverse direction so that semaphore arm U for signal l2, which is being energised in the normal direction by the line conductors for section WX, will become released. The releasing of semaphore arm U for signal 22 will cause contact |'|.23 of that signal to become. closed so that relay SEER will become energized in the reverse direction. This energization of relay IZDR will cause relay iZDP to become energized so that both the caution circuit for semaphore arm U of signal i2 and a circuit for lamp Y of signal l2 will become established. When semaphore arm U reaches its 45 position, it will be held in that position by the caution circuit so that signal l2 will be in condition to indicate approach next signal at medium speed to an approaching train. The energization of the line circuit to the rear of location W will not be disturbed, since relay IZDP will become energized to close its front contacts to supply energy of the high value in the normal direction to such rear line circuit before semaphore arm U of signal l2 reaches its 60 position to open signal contacts 20-39 and 2I26.

It will be seen, therefore, that tumble-down of Referring now to Fig. 2, I have shown herein one signal and associated apparatus which, when included in a system with wires 10 and H at the right connected with wires 12 and "I3, respectively, at the left, will provide a three-block, fourindication system similar to that described for the system illustrated in Figs. 1A and 1B.

The principal difference between the apparatus illustrated in Fig. 2 and that illustrated in Figs. 1A and 1B is that in the latter the semaphore arm U, when in the normal proceed position, is directly connected to the line conductors for the forward section, whereas in Fig. 2, the semaphore arm never receives energy from the line conductors.

Semaphore arm U is provided with a contact l4-'|5 which is closed at all times except when the semaphore arm is in the vertical or proceed position, and with a contact 76-17 which is closed whenever the semaphore arm is in the 30 position or vertical position or at any point between these two positions, as well as with contacts I8 and 18 which are in engagement with contacts and SI, respectively, when the semaphore arm is in the 43 position or in the vertical position or at any point between these two positions, and are in engagement with contacts 82 and 63, respectively, when the semaphore arm is at any point below the 43 position.

Relay DR is connected to the conductors for the forward section over contact IS-11 and relay DP is controlled by front contact 84 of relay DR. Relay HR is connected to the line conductors for the forward section over back contact 85 or" relay DP so that, when relay DP is energized, relay'I-IR will be deenergized to conserve energy as well as to avoid the possibility that the winding of relay HR. might act as a shunt path across relay DR thereby decreasing its release time. A resistor 86 is provided forlimiting the current flowing in the relay DR and a shunt path, including signal contact 74!5 is provided around resistor 8'6 so that whenever the semaphore arm U is in position other than the normal proceed position the relay DR will receive its normal current but, whenthe semaphore arm U is in the proceed position, relay DR will receive a reduced current which will insure a more positive release of this relay when the energization of the line conductors is changed from the high value to the low value.

The relays DR, DP and HR. control the semaphore arm U and lamp Y in the following manner: When relay HR is energized, a caution circuit for semaphore arm U becomes closed over front contact 31 of relay HR so that the semaphore arm is caused to assume the 45 position to indicate approach next signal prepared to stop. When relay DR becomes energized in the reverse direction, relay. DP also becomes energized to close another caution circuit for the semaphore arm and to establish a circuit for the lamp Y so that, when relay ER becomes released to close back contact 93, the signal will display the semaphore arm in the 45 position over a yellow light to indicate approach next signal at medium speed. The caution circuit for the semaphore arm includes front contact 88 of the relay DP and the circuit for lamp Y includes front contact 88 of relay DP as well as front contact 89 and reverse polar contact 96-41! both of relay DR. When relay DR is energized in the normal direction, relay DP, of course, remains,

energize-d so that the caution circuit remains closed and a proceed circuit is closed to cause the semaphore arm U to assume the vertical position to indicate proceed at normal speed. The proceed circuit includes front contact 38 of relay DP as well as front contact 39 and normal polar contact 90-92 both of relay DR.

The magnitude and direction of the energy supplied to the conductors for the rear section is controlled by the relays DP and HR and contacts l8 and I9 inthe following manner: When the semaphore arm is in its horizontal or stop position, the line conductors for the rear section are connected in the reverse direction with terminals Bi and C of battery ll through signal contacts 18-82 and 'l983. When the relay HR is energized and the semaphore arm is in the 45 position, the line conductors for the rear section are connected in the reverse direction to terminals B2 and C of battery I over front contact 94 of relay HR, back points of contacts 95 and 96 of relay DP and signai contacts 78"8il and "Hr-Bl. When the relay DR, is energized so that the relay DP is energized, the line conductors for the rear section are connected in the normal direction to terminals B2 and C of battery ll through front points of contacts 95 and 86 of relay DP and signal contacts it-J!) and 79--8|. The line conductors for the rear section, therefore, are supplied with energy of relatively low value in the reverse direction when the signal and associated apparatus is in condition to indicate stop, or with energy of relatively high value in the reverse direction when the signal and associated apparatus is in condition to indicate approach next signal prepared to stop, or with energy of relatively high value in the normal direction when the signal and associated apparatus is in condition to indicate either ap proaoh next signal at medium speed or proceed at normal speed.

Although have herein shown and described only a few forms of apparatus embodying my invention, it isunderstood 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' ceiving current from said conductors, and traffic governing means for said section controlled by said two relays.

In combination, a section of railway track, a pair of conductors for said section, means for supplying said pair of conductors with energy of a relatively low value or with energy of relatively high value in the reverse direction or with energy of said relatively high value in. the normal direction in accordance with trafiic conditions in advance or" said section, a neutral relay responsive to energy of said low value receiving current from said conductors, a polarized relay responsive only to energy of said high value also receiving current from said conductors, and a signal for said section caused to indicate approach? when said neutral relay is energized or to assume a condition to indicate approachmediumf when said polarized relay is energized in the reverse direction or to. indicate proceed when said polarized relay is energizedin the normal direction.

3. In combination, a section of railway track, a pair of conductors for said section, means for supplying said pair of conductors with energy of a relatively low value or with energy of relatively high value in the reverse direction or with energy of said relatively high value in the normal direction in accordance with trafiic conditions in advance of said section, a neutral relay'responsive to energy of said low value receiving current from said conductors, a polarized relay responsive only to energy of said high value also receiving current from said conductors, an auxiliary relay which becomes energized or. deenergized according as said polarized relay is energized or deenergized, a signal for said section including a first indication unit and a second indication unit, said first indication unit being a semaphore arm capable of assuming a stop and a caution as well as a proceed position and said second indication unit being a lamp, a caution circuit for said semaphore arm including a front contact of said neutral relay, another caution circuit for said semaphore arm including a front contact of said auxiliary relay, a proceed circuit for said semaphore arm including a front con tact of said auxiliary relay as weli as a front neutral contact and a normal polar contact both of said polarized relay, and a circuit for said lamp including a front contact of said auxiliary relay as well as a front neutral contact and a reverse polar contact both of said polarized relay.

4. In combination, a forward and a rear section of railway track, a neutral relay and a polarized relay for said forward section, means effective when the forward section is unoccupied to energize only said neutral relay or only said polarized relay in one direction or only said polarized relay in the other direction in accordance with traffic conditions in advance of said forward section, a pair of conductors for the rear section, means effective to supply said conductors with energy of a relatively low value when both said relays are deenergized, means effective to supply said conductors with energy of relatively high value in one direction when said neutral relay only is energized, means effective to supply said conductors with energy of said relatively high value in the other direction when said polarized relay is energized in either direction, and traffic governing means for the rear section receiving energy from said pair of conductors and selectively responsive to the value and direction of the current received therefrom.

5. In combination, a forward and a rear section of railway track, a neutral relay and a polarized relay for said forward section, means effective when the forward section is unoccupied to energize only said neutral relay or only said polarized relay in one direction or only said polarized relay in the other direction in accordance with trafiic conditions in advance of said forward section, a repeating relay which becomes energized or deenergized according as said polarized relay is energized or deenergized, a signal for said section caused to display a proceed indication when either said repeating relay or said neutral relay is energized, a pair of conductors for the rear section, means effective to supply said conductors with energy of a relatively low value when said signal is in condition to indicate stop, means effective to supply said conductors with energy of a relatively high value in the reverse direction when said neutral relay is energized provided said repeating relay is deenergized and said signal is in condition to display said proceed indication, and means effective to supply said conductors with energy of said relatively high value in the normal direction when said repeating relay is energized provided said signal is in condition to display said proceed indication.

6. In combination, a forward and a rear section of railway track, a neutral relay and a polarized relay for said forward section, means effective when the forward section is unoccupied to energize only said neutral relay or only said polarized relay in one direction or only said polarized relay in the other direction in accord ance with traffic conditions in advance of said forward section, a repeating relay which becomes energized or deenergized according as said polarized relay is energized or deenergized, a signal for said section caused to display a proceed indication when either said repeating relay or said neutral relay is energized, a pair of conductors for the rear section, a first contact and a second contact both of which are closed when said signal is displaying a stop indication and a third contact which is closed when said signal is displaying said proceed indication, a pair of line conductors for the rear section, a source of energy having a low voltage terminal and a high voltage terminal, means including said first contact and said second contact as Well as a back contact of said repeating relay for connecting said conductors to said low voltage terminal, means including said third contact and a front contact of said neutral relay as well as a back contact of said repeating relay for connecting said conductors to said hi h voltage terminal in one direction, and means including said third contact and a front contact of said repeating relay for connecting said conductors to said high voltage terminal in the other direction.

7. In combination, a stretch of railway track divided into sections, a pair of conductors for each section, means effective when one section is occupied to supply the conductors for the section next in rear of such occupied section with energy of a particular magnitude, means then effective to supply the conductors for the section second in rear of such occupied section with energy of a different magnitude in one direction, means then effective to supply the conductors for the section third in rear of such occupied section with energy of said different magnitude in the other direction, and trahic governing means for each section selectively responsive to the direction and magnitude of the energy supplied to the associated conductors.

8. In combination, a stretch of railway track divided into sections, a pair of conductors for each section, means effective when one section is occupied to supply the conductors for the section next in rear of such occupied section with energy of a relatively low value in one direction, means then effective to supply the conductors for the section second inrear of such occupied section with energy of a relatively high value in said one direction, means then effective to supply the conductcrs for the section third in rear of such occupied section with energy of said relatively high value in the other direction, and traffic governing means for each section selectively responsive to the direction and value of the energy supplied to the associated conductors.

9. In combination, a section of railway track, a pair of conductors for said section, a first signal control relay and a second signal control relay, both receiving energy from said pair of conductcrs, means including said pair of conductors effective when said section is unoccupied to energize said first signal control relay or to energize said second signal control relay in accordance with trafiic conditions in advance of said section, a signal for said section governed by said two relays and caused to assume one condition when said first signal control relay is energized or another condition when said second signal control relay is energized, means effective to deenergize said first signal control relay when said second signal control relay is energized, means effective to deenergizesaid second signal control relay when said signal is in such other condition, and means including a back contact of each of said two relays for then connecting said signal direct to said pair of conductors.

10. In combination, a section of railway track, a pair of conductors for said section, a first signal control relay and a second signal control relay both receiving energy from said pair of conductors, means including said pair of conductors effective when said section is unoccupied to energizensaid first signal control'relay or to energize said second signal control relay in accordance with trafiic conditions in advance of said section, a signal for said section governed by said two relays and caused to assume one condition when said first signal control relay is energized or another condition when said second signal control relay is energized, means effective to deenergize said first signal control relay when said second signal control relay is energized,

means eifective to deenergize said second signalv control relay when said signal is in such other condition, and means including a contact operably governed by said signal as well as a back contact of said first signal control relay and a back contact of said second signal control relay for then connecting *said signal to said pair of conductors.

11. A railway signal system comprising a stretch of railway track divided into sections, a pair of line conductors for each section, means for each section for supplying the conductors for the section next in rear with energy of relatively low value in one direction or with energy of relatively high value in the same direction or with energy of said high value in the other direction in accordance with traffic conditions in advance, a neutral relay for each section responsive to energy of said low value receiving current from the associated conductors, a polarized relay for each section responsive only to energy of said high value also receiving current from theassociated conductors, and trafiic governing means for each section controlled by the associated neutral and polarized relays. V I

12. A railway signal system comprising a stretch of railway track divided into sections, a pair of line conductors for each section, means for each section for supplying the conductorsfor the section next in rearlwith energy of relatively low value in one direction or with energy of relatively high value in the same direction or with energy, of said high Value in the other direction in accordance with traffic conditions in advance, a neutral relay for each section responsive to energy of said low value receiving current from the associated conductors, a polarized relay for each section responsive only to energy of said high value also receiving current from the associated conductors, and a signal for each section governed by the associated relays, each said signal being capable of displaying at least three different proceed indications.

' PAUL- H. CRAGO.

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