US2526429A - Light out protection for railway signaling systems - Google Patents

Description

C. E. STAPLES Oct. 17, 1950 LIGHTOUT PROTECTION FOR RAILWAY SIGNALING SYSTEMS Filed Jan. 2, 1948 IN V EN TOR.

frai /[7d E. Siapla! BY 4 I my ATTORNEY Patented Oct. 17, 1950 LIGHT OUT PROTECTION FOR RAILWAY SIGNALING SYSTEMS Crawford E; Staples, Pittsburgh, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application January 2, 1948, Serial N 0. 296

My invention relates to railway signaling systems, and particularly to improved means for providing lightout protection for a signaling system and means for checking the proper operation of the searchlight; type of signals employed in such systems.

It is an object of my invention to provide a signaling system in which a lightout relay checks that the filament of the signal lamp is intact and also checks that the signal operating mechanism is positioned in agreement with the contacts of the control relays which control the mechanism.

Another object of my invention is to provide means which operates so that if a signal should be displaying astop aspect when it is not, due to improper position of the mechanism or failure of the lamp, it will cause the signal next in the rear to display stop, and which also operates so that if a signal should be displaying an approach or a proceed aspect but cannot because the lamp is burned out or the signal operating mechanism is improperly positioned, the signal next in the rear will be caused to display an approach aspect.

A further object of my invention is to prevent a signal of the searchlight type from momentarily displaying a stop aspect on changing from the approach aspect to the proceed aspect or vice versa.

In practicing my invention, I provide a lightout relay having a high resistance winding and a low resistance winding. Normally the high resistance winding of the lightout relay is connected in series with the filament of the signal lamp of a searchlight type of signal by a circuit which includes in series the contacts of the control relays which govern the circuit of the signal winding, and also includes checking contacts of the signal mechanism so that sufiicient current will flow through the high resistance winding of the lightout relay to pick up its contact, but the lamp does not receive sufficient current to be lighted.

When a train approaches a signal, an approach relay operates and the low resistance winding of the lightout relay is connected in multiple with the high resistance windingand suflicient current then flows through the lamp to light it, and cause the signal to display one or another of its various aspects depending on the position of the signal mechanism; If the lamp is burned out, or if the position of the signal operating mechanism does not correspond with that of the control relays, the circuit of the light- 15 Claims.- (Cl. 24653) out relay is interrupted and no energy is supplied to the lightout relay or the signal lamp.

If the track section protected by the signal is unoccupied, the release of the lightout relay will result in controlling the next signal in the rear to display an approach aspect, but if the track section protected by the signal is occupied, the release of the lightout relay will result in controlling the next signal in the rear to display a stop aspect.

Other objects of my invention and features of novelty will be apparent from the following description taken in connectionwith the accompanying drawing.

The accompanying drawing is a diagrammatic view showing one form of signaling system embodying my invention.

Referring to the drawing, reference characters I and 2 designate the track rails of a stretch of railway track over which trafilc normally moves in a direction indicated by the arrow, that is, from left to right. These track rails are divided, by means of insulated joints 3, to form block sections. One block section is shown, identified as section 2T, together with portions of two other sections identified as IT and ST, re-

spectively.

Each block section is provided with a, coded 'track circuit including a code following track relay; such as relay 2TB, connected across the rails at the entrance end of the section, and atrack battery, such'as battery 2TB, located at the exit end of the section. The supply of energy from the track battery to the code following relay over the rails of the section is governed by a transmitting relay, such as relay 2CTP, the contacts of which are operated at various code rates, such as, for example, or times per minute. The recurrent operation of .the contacts of the'code following track relay'is decoded to control the wayside signal associated therewith in a manner to be subsequently explained.

Located adjacent the entrance end of each block is a signal designated by the reference character 8 with a prefix corresponding to the signal location. Each signal, asherc shown, is of the type co mmonly known as searchlight signal, and comprises an armature 5 mounted to rotate between an intermediate position to which it is biased, and two extreme positions. Each armature 5 is controlled by an armature winding 6, and is polarized by the field from permanent magnet or an electromagnet, not shown, in such a manner that when the winding 6 is energized, the armature 5 will rotate to one or the other or its extreme positions according as winding 6 is then supplied with current of normal or reverse polarity, respectively. Attached to each armature to rotate therewith are three colored roundels R, Y and G, which are arranged so that the roundel R. is disposed in the path of a beam of light projected from an associated lamp L when the armature 5 occupies its intermediate position, and so that the roundel Y or G is disposed in the path of a beam of light projected from the lamp L according as the armature 5 is rotated in a clockwise or a counterclockwise direction to one extreme position or the other. For convenience in illustration, the lamp L in the drawing is shown disposed, above the associated roundels, but it will be readily understood that in actual practice the lamp will be located directly back of the associated roundel and will have associated therewith a suitable optical system, not shown, for projecting beam of light from the lamp. The signal indicates proceed, stop, or approach, according as the roundel G, R or Y'is in front of the associated lamp L when this lamp is lighted. Operatively connected with each armature 5 is'a circuit controllfer comprising two movable contact fingers 'l and-8. The movable contact finger l cooperates with a fixed contact 1a to close a contact l'ia when the armature occupies the position in which the yellow roundel Y is located in front of the lamp, and cooperates with a fixed contact 12) to close a contact 'llb when the armature occupies either its intermediate position or the position in'which the green roundel G is located in frontof the lamp. Similarly, the movable contact finger B cooperates with a fixed contact to to close-a contact 8-8awhen the armature occupies the position in which the green roundel G is located in front of the lamp, and cooperates with 'a fixed contact 82) to close a contact 8-8b when the armature occupies either its intermediate position or the position in which the yellow roundel Y is located in front of the lamp. A signal of the type described is disclosed and claimed in Letters Patent of the United States, No. 1,864,224, granted to Wesley'B. Wells, on June 21, 1932, for Light Signals. It will be apparent to those skilled in the art, that my invention is equally applicable to semaphore type signals.

Energy for the operation of the relays other than the track relay is furnished from a suitable source of direct current, not shown, the positive and negative terminals of which are designated by the reference characters B and C, respectively.

The equipment is shown in the condition which it assumes when the track stretch is vacant. At this time energy of 180 code frequency is supplied to therails'of section 2T from battery 2TB by the recurrent operation of contact ID of transmitter relay 2CTP. The transmitting relay ZCTP is governedin a manner similar to that of relay ICTP which will be subsequently explained.

The energy supplied from battery 2TB operates the contact of relay 2TB, 180 times per minute, and each time contact [2 of relay 2TB, picks up, energy is supplied to the winding of a slow releaserelay 2FSA by the circuit traced from terminal B, over front contact 12 of relay ZTR, and through the winding of relay ZFSA to terminal C. Each time that contact l2 of relay ZTR releases, energy is supplied to the winding of a slow release relay ZBSA, over the circuit which is traced from terminal B, over back contact i 2 of relay 2TB, front contact 14 of relay ZFSA, and through the winding of relay ZBSA to terminal C. The relays ZFSA and ZBSA are slow enough in releasing to bridge the normal operating time of the contacts of relay 2TB. It will be apparent that during the time that contact !2 of relay ZTR is being operated in response to impulses of coded energy supplied over the rails of section 2T that the relays ZFSA and ZBSA will be picked up, while should the contact l2 of relay ZTR remain continuously picked up or continuously released, the relay ZBSA will be subsequently deenergized and its contacts will release. Accordingly, at this time, with section 2T unoccupied, relay 2TB is operating its contacts, so that relay ZBSA is energized and its contacts are picked up.

At this time the circuit for supplying energy to the primary winding of transformer DT is interrupted by contact 44 of relay AP so energy is not supplied to relay 2DR and its contacts are released.

As relay ZBSA is picked up and relay ZDR is released energy is supplied to the winding 6' of the signal mechanism of signal 28 by a circuit which is traced from terminal B, over front contact [5 of relay ZBSA, over back contact l8 of relay ZDR, through the winding 6 of the signal mechanism, over back contact 20 of relay 2DR, and over front contact 22 of relay ZBS'A to terminal C. The equipment is arranged and constructed so that the fiow of energy to winding 6 of signal mechanism as described above causes the armature to rotate in a clockwise direction to the extreme position in which the yellow roundel Y is positioned before the lamp L. It will be apparent therefore that if the lamp L should be lighted at this time the signal 2S would display a yellow aspect.

A circuit is established at this time for supplying energy to the winding of relay ZLOAR.

. This relay is provided with two windings, a high resistance winding 24, and a low resistance winding 2'6, the high resistance winding 24 being bridged by a rectifier Ka and the low resistance winding 26 being bridged by a rectifier Kb. As this time a circuit is established for supplying energy to the high resistance winding 24, and is traced from terminal B, through the winding 24 of relay ZLOAR, over-front contact 28 of relay ZBSA, over back contact 36 of relay ZDR, over contact '|la of the signal operating mechanism, over contact 88b of the mechanism, and through the lamp L to terminal C. The resistance of the winding 24 of relay-ZLOAR is such that sufficient energy flows through this winding to pick up the relay contacts, but sufiicient energy is not supplied to the lamp L at this time to cause the lamp to become lighted.

The code transmitters IBUCT and IECT are of the well-known pendulum coder type, having contacts which are continuously operated and 75 times per minute, respectively. At this time coded energy is supplied to the transmitting relay ICTP over the circuit which is traced from terminal B, over contact 32 of code transmitter QSBCT, over front contact 34 of relay ZLOAR, over front contact 36 of relay ZBSA and through the winding of relay ICTP-to terminal C. Accordingly, the contact 38 of relay ICTP is operated at the 180 code rate to supply impulses of coded energy of the same frequency to the section IT. These impulses operate the track relay, not shown, at the other end of the section to cause the signal atthe rear of signal 28 to display a green or proceed aspect on the approach of a train.

Additionally, the energy supplied to the rails of section IT at this time operates the code folfrom left to right, passes the signal in the rear, j of signal 25 and enters section IT. When the train comes within a specified distance of signal 2S for example, say 4000 ft., the wheels and axles ofthe train'shunt the supply of energy-to'the winding of approach relay ZAR, and its contact 40 releases and remains released. As a result, energy is no longer supplied to the repeater-relay 2AP, and after a short time interval its contacts release. When contact 42 of relay 2AP releases, the supply of energy to the second repeater relay ZAPP is interrupted, but the contacts of this relay remain picked up for a substantial time interval. When contact 44 of relay ZAP releases it establishesa circuit for supplying energy to the primary winding of transformer 2DT. This circuit is traced from terminal B, over front contact 46 of relay ZBSA, over back contact 44 of relay ZAP, and through the contact 48 of relay 2TB to the primary winding 50 of decoding trans former DT. When contact 48 of relay 2TB is released, energy is supplied to the lower half of primary winding 50 of transformer DT, and when contact 48 of relay 2TB is picked up, energy is supplied to the upper half of primary winding 50 of transformer DT. Since the contact 48 of relay 2TB is'operating atthe 180 code rate at this time, it will be apparent that an alternating current of 180 code frequency is induced inthe secondary winding 52 of transformer DT. by the operation of contact 48 of relay ZTR. This alternating current is supplied to the resonant decoding and rectifying unit IBUDU, of a type well-known in the railway signaling art, whose output is supplied to the winding of relay 2DR.

The decoding unit ISUDU is constructed and.

arranged so that sufficient energy will be supplied to the relay ZDR to pick up its contacts when and only when energy of the 180 code frequency is supplied to the decoding unit. At this time therefore, sufficient energy is supplied to the winding of relay 2DR to pick up its contacts. When the contacts [8 and 2B of relay ZDR pick up, the supply of energy to the winding 6 of the signal mechanism is pole-changed and energy is supplied thereto by a circuit which is traced from terminal B,- over front contact [5 of relay 2BSA, over front contact 20 of relay ZDR, through the winding 6 of the signal mechanism, over front contact l8 of relay 2DR, and over front contact 22 of relay ZBSA- to terminal C. As a result, the armature 5 of the signal mechanism is rotated in a counterclockwise direction to the extreme position in which the green roundel G is in front of the lamp L. Additionally, the contacts I and 8 of the signal mechanism are moved to their opposite positions so that contacts 1 engages contact 1b and contact 8 engages contact 8a. The lightout relay ZLOAR is now energized by a circuit whichpis traced 2LOAR, over front contact 28 of relay ZBSA, over front contact 30 of relay ZDR, over contact 8-8a of the signal mechanism and through the lamp L to terminal C. The rectifier snub Kc,

' shunt the winding of relay ZTR and the contacts of relay 2TB release and remainreleased. The;

prevents the relay 2LOAlt-from releasing duringthetime contact 30 of rel ay 2DR and contact s '1 and 8 of signal mechanism are; changing positions.

As previously explained, when contact 42 of relay 2AP releases,,it interrupts the supply of energy to the second slow release repeater relay 2APP, and after a substantial time interval, con-v tact 54 of this relay releases.

tioned before c0ntact54of relay ZAPP-releases When contact 54 of relay 2APP releases, it establishes the circuit for supplying energy through the low resistance winding 26 of relay ZLOAR to the lamp L of signal 23 in series with theqcon-. tacts of relays 2BSA, 2DR, and the contactsof the signal mechanism. This circuit is traced.

from terminal B, over back contact 54 of relay; 2APP, through the winding 26 of relay ZLOAR; over front contact 28 of relay 2BSA, over front contact 30 of relay 2BR, over contact 88a, of the signal mechanism and through the lamp L to terminal C. The resistance of the winding 25 of relay ZLOAR is low enough so that suflicient energy now flows through the lamp L to causetioned in front of the lamp L, and the lamp-L is illuminated, to thereby cause signal 2S. to=- display a green or proceed aspect to the approaching train.

When the train under discussion passes signal 2 2S and enters section 2T its wheels and axles cessation of operation of contact l2 of relay 2TB interrupts the supply of energy to the relays ZFSA and 236A, and after a short time interval 7 their contacts release. Additionally, when confrom terminal B, through the winding 24 of relay;

tact 46.0f relay -2BSA releases and when contact a 48.01 relay2TR releases and remains released, energy. is no longer supplied through the decoding transformer D'I' and the decoding unit IDU to the relay ZDR, and its contacts release. When contacts 16 and 22 of relay 2BSA release, the supply of energy to the winding 6 of the signal mechanism is cut off, and the biasing means causes the armature 5 to move to its intermediate position, so that the red roundel R is positioned in front of the lamp L, to thereby cause the signal 2S to display a red or stop aspect. When contact 46 of relay 2BSA releases it interrupts the circuit .for supplying energy over back contact 44 of 8a and engages contact 82), and contact 1 is disengaged from contact la and engages contact 1b. At this time contact 28 of relay ZBSA is released, and a circuit is now established for supplying energy to the relay ZLOAR which is traced from The release timeof, relay ZAPP is made sufficiently long to insure, that the mechanism of signal 28 will be positime the terminal B through winding 24 of I relay =2LOAR,

additionally from terminal B overback eontact their new positions; the circuit for the lamp will beinterrupted, but the rectifieresnubs Ka and'K-b connectedacross the windings 2 and'26,-respec tively, of relay ELOAR will cause the *relay contacts-to remain picked up "until the contacts of the signal mechanism are positioned as previously described.

At' this time the transmitterrelay ICTP is governed'by'the circuit which is traced from-terminal Bgovercontact 5t 01" code transmitter'lSCT, over front contact'tt olPrelay'ZLOAR, over back contactu36 of relay -2BSA and through the winding of relay ICTP to terminal C. As a'result, contact 38 of relay lCTP is operated at the 75 code rate, thus supplying from battery ITB to the rails of'section IT energy which is coded 75 times per minute. Since the rear portion of the train still occupies section IT, the energy will be shunted away from the winding of relay- ZAR so that contact 40 of relay ZAR remains released.

When the rear of a train vacates section lT, the energy supplied from battery ITB at the rate of 75 impulses per minute feeds over the rails of section IT to the'track relay associated with the signal in the rear, to thereby cause that signal to display a yelow or approach aspecton the approach of a train. Additionally, the'relay EAR no-w receives impulses of energy, and its contact 40 is recurrentlypicked up and released 75 times per minute, to thereby energize the repeaterrelay-2AP. When relay ZAP picks up, its front contact-42 again establishes the circuit for supplying energy to relay ZAPP and its contact picks up. Also, when contact 46 of relay ZAP picks up it additionally interrupts the circuit for supplying l energy to-the decoding transformer DT, the decoding unit I3EDU and the relay 2BR, which circuit, as previously explained, is interrupted at this time by a contact 36 of relayZBSA. ilvhen relay ZAPP picks up, its contact -5 interrupts the-circuit for connecting the low resistance winding 26 of relay 2LOAR in th circuit including the contacts of the control relays, th signal mechanism, and the lamp L. As result, the energy-supplied to this circuit is now insufficient to cause the lamp L to be lighted-and it becomes extinguished. However, as previously explained, the energy which flows through the winding 24 of relay 2LOAR is'suificient to cause the relay to maintain its contact picked up.

When the train vacates section ET, the supply of energy from battery 2TB will be coded at the rate of 75 times per minute by the relay ZCTP, which is governed in a manner similar to that previously explained for relay iC'lP, so that relay 2TB now receives energy at the '75 code rate. Contact l2 of relay QT-R now operates between its picked-up and released positions to alternately supply energy to relays ZFSA and ZBSA, and these relays become picked up. When relay ZB'SA becomes picked up, its front contacts I6 and 22 establish the circuit for supplying energy to the winding Ii of the signal mechanism of signal 2S, but since relay ZDR is released at this time, the polarity of the energy supplied to the 8 winding 6 of the signa1--mechanism causes the armature 5 to "move to the position in which the yellow rounclel *Y is positioned in front of the lamp L. At thistime contact I of the signal mechanism is moved out of engagement with contact 'Ib-and into engagement with contact Ia, and contact fi remains in engagement with contact'Sbso that the circuit previously traced for supplying energy to ZLOAR, which circuit includesfront contact-2S of relay ZBSA, back contact' 39 of'relay 2BR, the contacts of the'signal mechanism in the position described, and the lampL, all in series,-is again complete. As previously explained, the rectifier snubs across the windings 'fl i and 25 of relay ZLOAR prevent; the relay from releasing during this change of positions.

Relay ICTP is now operated at the 180 code rate by a circuit which includes contact '32 of codetransmitter' ISBCT front contact 3 1 of relay ZLOAR, front contact 36 of relay ZBSA, and the winding of relay lCTP. As a result, coded energy of the I code rate is now supplied to section IT to operate the track relay at the exit end of the section, to thereby cause the signal in the rear of signal 2S to display a green aspect on the approach of a train. Additionally, the approach relay -2AR now operates its contact 49 at the 180 code rate, and the relay ZAP continues to be picked up.

When relay 2BSA picks up, its contact-46 in the circuit for supplying energy to the decoding transformer DT is closed, but this circuit is now interrupted by contact 44 of relay ZAP so that energy is not supplied to the transformer DT at this time.

When the train under discussion vacates section3T, the relay ZCTP will be operated at the 180 code rate, and accordingly relay 2TB. will be supplied with energy at this code frequency. The recurrent operation of contact I2 will continue to maintain the relays .ZFSA and ZBSA energized, and the system is now returned to its normal condition as originally described.

It will now be assumed that with no train occupying section 2T, that the filament of lamp L burns out or breaks. It will be seen that this interrupts the supply of energy through the winding 24 of relay 2LOAR and its contacts release. When contact 34 of relay 2LOAR releases, it interrupts the supply of energy over the circuit governed by the 180 code transmitter to the relay ICTP and establishes a circuit governed by a contact of the 75 code transmitter for supplying energy to the winding of relay ICTP. This circuit is traced from terminal B, over contact 56 of code transmitter T, over back contact 34 of relay 2LOAR, over front contact 36 of relay ZBSA, and through the winding of relay ICTP to terminal C. As a result,'

energy is now supplied to the section rails of section IT at the 75 code rate, thereby causing the track relay at the entrance end of section IT to operate its contacts at that rate. As a result, the signal in the rear of signal 28 will be caused to display a yellow aspect toan approaching train, and an approaching train will pass the signal in the rear of signal 28 at reduced speed so as to be prepared to stop when it reaches signal 28. This is advantageous since the operating rules of most railroads require'that enginemen consider a, dark signal to be displaying the stop aspect, and if the signal in the rear of signal 28 were to display a proceed aspect at this time the train would proceed at its maximum authorized speed until it encountered a dark signal at location of signal 28, and it would be necessary to make a sudden and possibly dangerous application of the brakes.

In addition it will be apparent from the description of the circuits traced above, that not only will the failure of the filament of lamp L produce the results described above, but should the contacts of. the signal mechanism and the contact of the control relays be out of agreement, the circuit for supplying energy through the winding 24 of relay 2LOAR will be interrupted, producing the results described above.

My invention is also advantageous in that, should a signal be deranged in such manner that at a time when the signal should display a stop indication it does not, due to a burnedout lamp or to a defect in signal mechanism, the signal immediately in the rear of the defective signal will display a stop indication. This is advantageous in that it will require a following train to stop at least one block behind the signal which is defective, rather than permitting the train to approach the defective signal and possibly overrun the signal and hit a train cupying the section protected by the defective signal.

It will now be assumed that with a train occupying section 2T, the mechanism of the signal 28 is defective and does not return to its intermediate position to cause the signal to display a red aspect, but rather remains with its 'contacts as shown on the drawing, that is, with contact 7 engaging contact la. and contact 8 engaging contact 87). At this time contact 28 of relay ZBSA is released since the train occupies this section and contact l2 of relay 2TR remains released so that contact I4 of relay 2FSA interrupts the supply of energy to relay ZBSA. Accordingly, the circuit for supplying energy to the winding 24 of relay 2LOAR is interrupted by the contacts Ia and 1b of the signal mechanism and relay 2LOAR is released. As a result of the supply of energy to relay ICTP is cut off since the circuit including back contact 36 of relay ZBSA and front contact 58 of relay ZLOAR, which would normally connect the relay ICTP to receive coded energy from the '75 code transmitter, is interrupted due to contact 58 of relay 2LOAR being released. The relay ICTP, therefore, remains released and coded energy is not supplied to the rails of section IT. Accordingly, the track relay at the entrance end of section IT remains released, and causes the signal next in the rear of signal 28 to display a stop aspect to an approaching train.

Since the type of searchlight mechanism as herein shown and described and further shown and described in the above-referred to patent issued to Wesley B. Wells, is of a type in which the red roundel is placed before the lamp when the armature is in its intermediate position and the green or the yellow roundel is placed before the lamp when the armature occupies an extreme position, it will be seen that when the signal changes from yellow to green, or vice versa, that a momentary red flash occurs. My invention is advantageous in that such a flash is eliminated, since it will be seen that during the time that contacts of the control relays and the contacts of the signal mechanism are out of agreement, the series circuit including the lamp L of the signal will be interrupted, so that the lamp L will not be lighted.

It will be apparent to those skilled in the art, that my invention is applicable to any type of signaling system employing Searchlight or semaphore signals, whether the signals are controlled through the medium of coded track circuits, polarized track circuit, line wire circuits, or any of the other various systems in common usage.

Although I have herein shown and described only one form of signaling system embodying my invention, it is to be 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 section of railway track, a signal for said section, said signal being of a type which has a member biased to a first position in which it conditions the signal to provide one aspect and has a winding efiective when energized to move said member to a second position in which it conditions the signal to provide a difierent aspect, a mechanism contact operated by said member, said mechanism contact being closed in a first position when said member is in its first position and being closed. in a second position when said member is in its second position, a lamp for causing said signal to display an aspect when said lamp is energized, a control relay governed by traffic conditions in said section, a circuit controlled by a front contact of said control relay for supplying-energy to the winding of said signal, a lightout relay, a first circuit for supplying energy to said lightout relay in series with said lamp including said mechanism contact closed in its first position and a back contact of said control relay in series, and a second circuit for supplying energy to said lightout relay in series with said lamp including said mechanism contact closed in its second position and a front contact of said control relay connected in series.

2. In combination, a section of railway track, a signal for said section, said signal being of a type which has a member biased to a first position in which it conditions the signal to provide one aspect and has a winding effective when energized to move said member to a second position in which it conditions the signal to provide .a different aspect, a mechanism contact operated by said member, said mechanism contact being closed in a first position when said member is in its first position and being closed in a second position when said member is in its second position, a lamp for causing said signal to display an aspect when said lamp is energized, a control relay governed by trafiic conditions in said section, a circuit controlled by a front contact of said control relay for supplying energy to the winding of said signal, a lightout relay having a high resistance Winding and a low resistance winding, a first circuit for supplying energy to the high resistance winding of said lightout relay in series with said lamp including said mechanism contact closed in'its first position and a back contact of said control relay in series, a second circuit for supplying energy to the high resistance winding of said lightout relay in series with said lamp including said mechanism contact closed in its second position and a front contact of said control relay connected in series, an approach relay for said signal, and a circuit. governed by said approach relay for connecting said low resistance winding in 11 multiple with said high resistance winding of the lightout relay, said high resistance winding being proportioned so that the value of energy which flows therethrough is eifective to energize said lightout relay but not effective to light said lamp and said low resistance winding being proportioned so that the value of energy which fiows therethrough is effective to energize said lightout relay and light said lampv 3. In combination, a section of railway track, a signal for said section, said signal being oi a type which has a member biased to a first position in which it conditions the signal to provide a first aspect and has a winding effective when supplied with energy of reverse polarity to move said member to a second position in which it conditions the signal to provide a second aspect and when supplied with energy of normal polarity to move said member to a third position in which it conditions the signal to provide a third aspect, a lamp for causing said signal to display an aspect when said lamp is energized, a first control relay governed by trafiic conditions in said section, a second control relay governed by traffic conditions in advance of said 7 section, a circuit including a front contact of said first control relay and a back contact of said second control relay for supplying energy of reverse polarity to the winding of said signal, a circuit including front contacts of said first and said second control relays for supplying energy of normal polarity to the winding of said signal, a lightout relay, a first circuit including in series a back contact of said first control relay for supplying-energy to said lightout relay in series with said lamp provided said signal member is in its first position, a second circuit including in series a front contact of said first control relay and a back contact of said second control relay for supplying energy to said lightout relay in series with said lamp provided said signal member is in its second position, and a third circuit including in series front contacts of said first and said second control relays for supplying energy to said lightout relay in series with said lamp provided said signal member is in its third position.

4. In combination, a section of railway track, a signal for said section, said signal being of a type which has a member biased to a first position in which it conditions the signal to provide a first aspect and has a winding efiective. when supplied with energy of reverse polarity to move said member to a second position in which it conditions the signal to provide a second aspect and when supplied with energy of normal polarity to move said member to a third position in which it conditions the signal to provide a third aspect, a lamp for causing said signal to display an aspect when said lamp is energized, a first control relay governed by trafic conditions in said section, a second control relay governed by traflic conditions in advance of said section, a circuit including a front contact of said first control relay and a back contact of said second control relay for supplying energy of reverse polarity to the winding of said signal, a circuit including front contacts of said first and said second control relays for supplying energy of normal polarity to the winding of said signal, a lightout relay having a high resistance and a low resistance winding, 2. first circuit including in series a back contact of said first control relay for supplying energy to the high resistance winding of said lightout relay in series with said lamp-provided said signal'member is in its first position, a second circuit including in series a front contact of said first control relay and a back contactlof said second control relay for supplying energyto the high resistance Winding of said lightout relay in series with said lamp provided said signal member is in its second position, a third circuit including in series front contacts of said first and said second control relays for supplying energy to the high resistance winding of said lightout relay in series with said lamp provided said signal member is in its third position, an approach relay for said signal, and a circuit governed .by said approach relay for connecting said low resistance winding of the lightout relay in multiple with the high resist ance winding of the lightout relay, said high resistance winding being proportioned so that the value of energy which flows therethrough is effective .to energize the lightout relay but is not effective to light said lamp, .and said low resistance winding being proportionedsolthat the value of energy which .fiows therethrough is effective to energize'the lightout relay and light said lamp.

5. In combination with a section of railway track, means governed by tra'flic conditions in advance of said section for at times supplying to the rails of said sectioncoded energy of a first character and at other times of a second. character, a code following track :relay operated by energy supplied over the railsof said section, a first and a second control relay associated with said track relay, means effective when the track relay is responding to energy of either character to energize said first control relay and effective only when the track relay is responding to energy of the second character to energize said second control relay, a signal for said section, said signal being of a type having a member biased to a :first position in which it conditions the signal to provide a first aspect and having a winding effective when energized with current of reverse polarity to move said member to a second posi tion in which it conditions the signal to provide a second aspect and effective when energized with current of normal polarity to move said member to a third position in which it conditions the signal to provide a third aspect, a lamp for causing said signal to display an aspect when said lamp is energized, a circuit including a front contact of said first control relay and a back contact of said second control relay for supplying energy of reverse polarity to the winding of said signal, a circuit including front contacts of said first and second control relays for supplying energy of normal polarity to the winding of said signal, a lightout relay, a first circuit including in series a back contact of said first control relay for supplying energy to said light out relay in series with said lamp provided said signal member is in its first position, a second circuit including in series a front contact of said first control relay and a back contact of said second control relay for supplying energy to said lightout relay in series with said lamp provided said signal member is in its second position, and a third circuit including in series front contacts of said first and said second control relays for supplying energy to said lightout relay in series with said lamp provided said signal member is in its third position.

13 to the rails of said section coded energy of a first character and at other times of a second character, a code following track relay operated by energy supplied over the rails of said section, a first and a second control relay associated with said track relay, means effective when the track relay is responding to energy of either character to energize the first control relay and eifective only when the track relay is responding to energy of the second character to energize the second control relay, a signal for said section, said signal being of a type having a member biased to a first position in which it conditions the signal to provide a first aspect and having a winding effective when energized with current of reverse polarity to move said member to a second position'in which it conditions the signal to provide a second aspect and effective when energized with current of normal polarity to move said member to a third position in which it conditions the signal to provide a third aspect, a lamp for causing said signal' to display an aspect when said lamp is energized, a circuit including a front contact of said first control relay and a back contact of said second control relay for supplying energy of reverse polarity to the winding of said signal,

a circuit including front contacts of said first and second control relays for supplying energy of normal polarity to the Winding of said signal, a lightout relay having a high resistance and a low resistance winding, a first circuit including in series a back contact of said first control relay for supplying energy to the high resistance winding of said lightout relay in series with said lamp provided said signal member is in its first position, a second circuit including in series a front contact of said first control relay and a :back contact of said second control relay for supplying energy to the high resistance winding of said lightout relay in series with said lamp provided said signal member is in its second position, and a third circuit including in series front contacts of said first and said second control relays for supplying energy to the high resistance winding of said lightout relay in series with said lamp provided said signal member is in its third position, an approach relay for said signal, and a circuit governed by said approach relay for connecting said low resistance winding of the lightout relay in multiple with the high resistance winding of the lightout relay, said high resistance winding being proportioned so that the value of energy which flows therethrough is effective to energize the lightout relay but is not effective to light said lamp, and said low resistance Winding being proportioned so that the value of energy which flows therethrough is effective to energize the lightout relay and light said lamp.

'7. In combination with a section of railway track, means governed by trafiic conditions in advance of said section for at times supplying to the rails of said section coded energy of a first character and at other times of a second character, a code following track relay operated by energy supplied over the rails of said section, a first and a second control relay associated with said track relay, means effective when the track relay is responding to energy of either character to energize the first control relay and effective only when the track relay is responding to energy of the second character to energize the second control relay, a signal for said section, saidsignal being of a type having a member biased to a first position in which it conditions the signal to provide a first aspect and having a winding effective when energized with current of reverse polarity to move said member to a second position in which it conditions the signal to provide a second aspect and effective when energized with current of normal polarity to move said member to a third position in which it conditions the signal to provide a third aspect, a lamp for causing said signal to display an aspect when said lamp is energized, a circuit including a front contact of said first control relay and back contacts of said second control relay for supplying energy of reverse polarity to the winding of said signal, a circuit including front contacts of said first and second control relays for supplying energy of normal polarity to the winding of said signal, a lightout relay, a first circuit including in series a back contact of said first control relay for supplying energy to said lightout relay in series with said lamp provided said signal memberis in its first position, a second circuit including in series a front contact of said first control relay and a back contact of said second control relay for supplying energy to said lightout relay in series with said lamp provided said signal member is in its second position, a third circuit including in series front contacts of said first and second control relays for supplying energy'to said lightout relay in series with said lamp provided said signal member is in its third position, means for governing another signalin the rear of said signal so that said other signal displays an aspect similar to said first aspect of said signal when said lightout relay and said first control relay are both released.

8. In combination a section of railway track, a signal for said section, a lamp for causing said signal to display an aspect when said lamp is energized, a control relay governed by trafiic conditions in said section and effective according as said relay is energized or deenergized to cause said signal to display a permissive or a stop aspect, a lightout relay having a winding to which energy is supplied through the filament of said lamp, and traffic governing means located in the rear of said signal and governed by-said control and lightout relays for governing traffic approaching said signal, said means being effective when said control relay is energized-to provide a permissive aspect at a point in the rear of said signal regardless of the condition ofsaid lightout relay and being effective when said con-- trol relay is deenergized to provide a permissive or a stop aspect at a point in the rear of said signal according as said lightout relay is energized or deenergized.

a 9. In combination a section of railway track, a signal for said section, a lamp for causingsaid signal to display an aspect when said lamp is energized, a control relay governed by traffic conditions in said section and effective according as said relay is energized or deenergized to cause said signal to display a permissive or a stop aspect, a lightout relay having a winding to which energy is supplied through the filamentof a lamp of said signal, and trafiic governing means located in the rear of said signal and governed by said control and lightout relays for governing traffic approaching said signal, said means being effective when said control relay is energized to provide a first or a second permissive aspect at a point in the rear of said signal according as said lightout relay is deener- -:;gized or is energized and being effective when said control relay is deenergized to provide said gfirst permissive aspect or a stop aspect at said when said control relay is released provided said signal member is in its first position, a second circuit for energizing said auxiliary relay when said control relay is picked up provided said sig nalmember is in its second position, and traffic governing means located in the rear of said signal and governed by said control and auxiliary relays for governing traific approaching said signal, said means being effective when said control relay is energized to provide a permissive aspect at a point in the rear of said signal regardless of the condition of said auxiliary relay and being effective when said control relay is deenergized to provide a permissive aspect or a stop aspect at said point according as said auxiliary relay is energized or deenergized.

11. In combination, a section of railway track, a control relay governed by traffic conditions in said section, an auxiliary relay, a signal for said section, said signal being of a type which has a member biased to a first position in which it conditions the signal to provide one aspect and has a winding effective when energized to move said member to a second position in which it conditions the signal to provide a difierent aspect, a first circuit for energizing said auxiliary relay when said control relay is released provided said signal member is in its first position, a second circuit for energizing said auxiliary relay when said control relay is picked up provided said signal member is in its second position, and means governed by said control and auxiliary relays for governing traific approaching said signal, said means being effective when said control relay is energized to provide a first or a second permissive aspect at a point in the rear of said signal according as said auxiliary relay is deenergized or is energized and being effective when said control relay is deenergized to provide said first permissive aspect or a stop aspect at said point according as said auxiliary relay is energized or is deenergized.

12. In combination, a section of railway track, a signal for said section having a lamp which when energized causes said signal to display an aspect, said signal being of a type which has a member biased to a first position in which it conditions the signal to provide a first aspect, said signal having a winding efiective when energized with current of reverse polarity to move said member to a second position in which it conditions the signal to provide a second aspect and effective when energized with current of normal polarity to move said member to a third position in which it conditions the signal to provide a third aspect, a control circuit for supplying energy to the winding of said signal, relay means governed by traffic conditions in advance of said signal, said relay means including contacts which at times occupy a first position in which they interrupt the circuit of the winding ofsaid signal, at other times occupy a second position in which energy of reverse polarity is supplied over said control circuit to the windin of said signal, and at still other times occupy a third position in which energy of normal polarity is supplied over said control circuit to the winding of said signal, a first circuit for supplyin energy to the lamp of said signal when the contacts of said relay means are in their first position provided said signal member is in its firstposition, a second circuit for supplying energy to the lamp of said signal when the contacts of said relay means are in their second position provided said signal member is in its second position, and a third circuit for supplying energy to the lamp ofsaid signal when the contacts of said relay means are in their third position provided said signal member is in its third position.

13. In combination, a section of railway track, a signal for said section, said signal being of a type which has a member biased to a first position in which it conditions the signal to provide a first indication, said signal having a winding efiectve when energized with current of reverse polarity to move said member to a second position in which it conditions the signal to provide a second indication and efiective when energized with current of normal polarity to move said member to a third position in which it conditions the signal to provide a third indication, relay means governed by traific conditions in advance of said signal, said relay means including contacts which at times occupy a first position in which they interrupt the circuit of the winding of said signal, at other times occupya second position in which they establish a circuit for supplying energy of reverse polarity to the winding of said signal, and at still other times occupy a third position in which they establish a circuit for supplying energy of normal polarity to the winding of said signal, a lamp for causing said signal to display an aspect when energized, and means for supplying energy to said lamp when and only when the position of said signal member and the position of the contacts of said relay means are in correspondence.

14. In combination, a section of railway track, a signal for said section, said signal being of a type which has a member biased to a first position in which it conditions the signal to provide one aspect and has a winding effective when energized to move said member to a second position in which it conditions the signal to provide a different aspect, a mechanism contact operated by said member, said mechanism contact being closed in a first position when said member is in its first position and being'closed in a second position when said member is in its second position, a lamp for causing said signal to display an aspect when said lamp is energized, a control relay governed by traffic conditions in said section, a circuit controlled by a front contact of said control relay for supplying energy to the winding of said signal, a lightout relay, a first circuit for supplying energy to said lightout relay in series with said lamp including said mechanism contact closed in its first position and a back contact of said control relay in series, and a second circuit for supplying energy to said lightout relay in series with said lamp including said mechanism contact closed in its second position and a front contact of said control relay connected in series, and traffic governing means located in the rear of said signal and governed by said lightout relay.

15. In combination, a section of railway track,

a signal for said section, said signal being of a type which has a member biased to a first position in which it conditions the signal to provide one aspect and has a winding effective when energized to move said member to a second position in which it conditions the signal to provide a different aspect, a mechanism contact operated by said member, said mechanism contact being closed in a first position when said member is in its first position and being closed in a second position when said member is in its second position, a lamp for causing said signal to display an aspect when said lamp is energized, a control relay governed by trafiic conditions in said section,-a circuit controlled by a front contact of said control relay for supplying energy to the winding of said signal, a lightout relay having a high resistance winding and a low resistance winding, a first circuit for supplying energy to the high resistance winding of said lightout relay in series with said lamp including said mechanism contact closed in its first position and a back contact of said control relay in series, a second circuit for supplying energy to the high resistance winding of said lightout relay in series 18 with said lamp including said mechanism contact closed in its second position and a front contact of said control relay connected in series, traffic governing means located in the rear of said signal and governed by said lightout relay, an approach relay for said signal, and a circuit governed by said approach relay for connecting said low resistance winding in multiple with said high resistance winding of the lightout relay, said high resistance winding being proportioned so that the value of energy which flows therethrough is efl'ective to energize said lightout relay but not effective to light said lamp and said low resistance winding being proportioned so that the value of energy which flows therethrough is effective to energize said lightout relay and light said lamp.

CRAWFORD E. STAPLES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,057,581 McCann Oct. 13, 1936 2,150,579 Crago Mar. 14, 1939

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