US2150579A - Railway signaling system - Google Patents

Description

March 14, 1939. P H CRAGO 2,150,579 RAILWAY SIGNALING SYSTEM H Original Filed-June .10, 1956 9 Sheets-Sheet 1 Fig.4.

INVENTOR Pa u Crago. BY g 2 f 1115 AT'II'ORNEY Mhrch 14, 1939. Y P. H, CRAGO 2,150,579

RAILWAY SIGNALING SYSTEM Original Filed June 1o, 1956 9 Sheets-Sheet 2 INVENTOIR Paul Crayo. BY

HAS ATIORNEY March 14, 1939. P H. CRAGO I 2,150,579

RAILWAY SIGNALING SYSTEM I Original Filed June 10, 1936- 9 Sheets-Sheet 3 INVENTOR Paul Cra 0.

HE ATTORNE Y March 14, 1939. P. H. CRAGO RAILWAY SIGNALING SYSTEM Original Filed June 10, 1936 9 Sheets-Sheet S H115 ATTORNEY March 14, 1939. P. H cRAGO RAILWAY SIGNALING ,SYSTEM I Original Filed'Jime 10, 1936 9 Sheets-Sheet e |NVlNTO pi Zjyago. BY

HIS ATTO RN EY March 14, P A

I x RAILWAY SIGNALING SYSTEM Original Filed June-.10, 1936 9 Sheets-Sheet 7 1111s ATTORNEY March 14, 1939. P. H. CRAGO RAILWAY SIGNALING SYSTEM 9 Sheets-Sheet 8 Original Filed June 10, 1956 Emmi . INVENTORN Paul BY 111$ ATTORNEY March 14, 1939. Pf O 2,150,579

' RAILWAY SIGNALING SYSTEM Original'F'iled June 10, 1936 9 Sheets-Sheet 9 INVENTOR ga. Cra.

HIS ATTORNEY Patented Mar. 14, 1939 UNITED STATES PATENT oFF cE.

RAILWAY SIGNALING SYSTEM Application June 10, 1936, Serial No. 84,498 Renewed June 24, 1938 42 Claims.

My invention relates to railway signaling systems of the type involving light signals which are approach. lighted.

One object of my invention is to provide novel '5 means for causing an approach lighted signal to display a restrictive indication when a train approaches the signal if the filament of the lamp for the signal next inadvance becomes burned out or broken.

Other objects of my invention will appear as the description proceeds.

The railway signaling system set forth in my present application is somewhat similar to that set forth in the copending application of Henry S. YoungQSerial No. 742,095, filed on August 30, 1934, for Railway signaling system, and the said copending application contains claims which cover broadly certain features of the invention described in my present application.

I will describe several forms of railway signaling systems embodying my invention, and will then point out the novel features thereof in claims.

n the accompanying drawings, Fig. 1 is a diagrammatic view showing one form of signaling system embodying my invention. Fig. 2 is 2. diagrammatic view showing a modification of the signaling system illustrated in Fig. 1. Figs. 3 and 3 are diagrammatic views which, when placed end to end with Fig. S on the right, show still another form of signaling system embodying my invention. Fig. 4 is a diagrammatic view showing a modification of the signaling system illustrated in Figs. 3 and 3. Figs. 5 and 5 are diagrammatic views which, when placed end to end with Fig. 5 on the right, show still another form of signaling system embodying my invention. Figs. 6 and 6 are diagrammatic views which, when placed end to end with Fig. 6 on the right, show still another form of signaling system embodying my invention. Fig. '7 is a diagrammatic view showing a modification of the signaling system illustrated in Figs. 6 and 6.

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

Referring first to Fig. 1, the reference characters l and I designate the track rails of a stretch of railway track along which traffic normally moves in the direction indicated by the arrow. These track rails are. divided, by means of insulated joints 2, to form blocks, only one of which, A-B, is shown complete in the drawings. Each block is provided with a track circuit comprising a track relay, designated by the reference character TR with a suitable distinguishing exponent,

and connected across the rails adjacent one end of the section, and a suitable source of track circuit current, here shown as a track battery 3, connected across the rails adjacent the other end of the section.

Located adjacent the entrance end of each block is a signal designated by the reference character S with an exponent corresponding to the location. Each signal, as here shown, is of the type commonly known as a 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 a permanent magnet or an electromagnet (not shown) in such manner that when the winding 6 is energized, the armature will rotate to its right-hand or lefthand extreme position according as winding 6 is then supplied with current of normal or reverse polarity, respectively. Attached to each armature 5 to rotate therewith are three colored roundels G, R, and Y, which are arranged-to be disposed in the path of a beam of light projected from an associated lamp L according as the armature 5 occupies its right-hand extreme position, its intermediate position, or its left-hand extreme position, respectively. For convenience in illustration, each lamp L in the drawings is shown disposed above the associated roundels, but it will be readily understood that in actual practice each lamp will be located directly back of the associated roundel. and will have associated therewith a suitable optical system, not shown, for projecting a beam of light from the lamp. The signals S each indicate proceed, stop, or caution 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 controller comprising two movable contact fingers l and 8. The movable contact finger l cooperates with a fixed contact l to close a contact 'I-J when the armature 5 occupies its right-hand extreme position, and with a fixed contact 1* to close a contact '|l when the armature occupies its intermediate position or its left-hand extreme position; while the movable contact finger 8 cooperates with a fixed contact 8 to close a contact !38 when the armature occupies its left-hand extreme position, and with a fixed contact 8 to close a contact 8-8 when the armature occupies its intermediate or its right-hand extreme position. A signal of the type described is disclosed and claimed in Letters Patent of the 55 United States No. 1,864,224, granted to Wesley B. Wells, on June 21, 1932, for Light signal.

Associated with each signal is a slow-releasing signal repeater relay designated by the reference character SR with a suitable distinguishing exponent, an approach lighting relay designated by the reference character ALR with a suitable distinguishing exponent, and a slow-releasing lightout relay designated by the reference character LOR with a suitable distinguishing exponent. Each lightout relay LOR is provided with two windings, one of which, 9, has a sufiiciently high resistance so that when this winding is connected in series with the filament of the lamp L of the associated signal in a checking circuit for the lamp presently to be described, the lamp will not become lighted, and the other of which, H], has a sufficiently low resistance so that when this winding is connected in series with the filament of the lamp L of the associated signal in an energizing circuit for the lamp presently to be described, the lamp will become lighted.

Each signal repeater relay is provided with two energizing circuits which are controlled by the circuit controller of the associated signal. Referring to relay SR for example, the one energizing circuit for this relay is closed when and only when signal S indicates proceed, and passes from terminal X of a suitable source of current not shown in the drawings through contact 'l'l of signal S wires 24 and 25, and the winding of relay SRr to terminal 0. The other energizing circuit for relay SR is closed when and only when signal S indicates caution, and passes from terminal X through contact 7-? of signal S wire 32, contact 88 of signal S wire 25, and the winding of relay SR to terminal O It will be apparent, therefore, that relay SR will be energized when signal S occupies either its proceed or its caution position, but will be deenergized when signal S occupies its stop position. Relay SR is made sufiiciently slow releasing so that it will not open its front contacts while signal S is moving from its proceed to its caution position, or vice-versa.

The winding 6 of each signal is controlled by the associated track and lightout relays and by the signal repeater relay for the signal next in advance, through the medium of a polarized line circuit which includes the winding of the approach lighting relay for the signal next in advance. Referring to signal S for example, when track relay PR and lightout relay LOR are both energized, and signal repeater relay SR is also energized, the polarized line circuit for winding 6 of signal S is closed, and under these conditions, winding 6 is supplied with current of normal polarity, the path of the current being from terminal X through the winding of relay ALR wire l2, front contact l3l3 of relay SR line wire ii, front contact l5 of track relay TR wire [6, front contact ll of lightout relay LO'R wire [8, winding 6 of signal S wire l9, front contact 20 of track relay TR line wire 2!, front contact 22- 22 of signal repeater relay SR and wire 23 to terminal Or. When track relay TB and lightout relay LOR are both energized and signal repeater relay SR is deenergized, the polarized line circuit for winding 6 of. signal S is again closed, but under these conditions, due to the fact that the back contacts i3-i3 and 22--22 of relay SR are then closed instead of the front contacts i3--l3 and 22-42 winding 6 of signal S is supplied with current of reverse polarity over this line circuit. When either track relay TR or lightout relay LOR is deenergized, the polarized line circuit for winding 6 of signal S will, of course, be open.

It will be apparent, therefore, that when track relay TR and lightout relay LOR are both energized, the mechanism of signal S will occupy its proceed or its caution position according as signal repeater relay SR is then energized or deenergized, but that, when either track relay TR or lightout relay LOR is deenergized, the mechanism of signal S will occupy its stop position. It will also be apparent that approach lighting relay ALR will be energized whenever winding 5 of signal S is energized by current of either normal or reverse polarity, but that, when winding 6 of signal S is deenergized, approach lighting relay ALR will also be deenergized.

Each signal lamp L is provided with an energizing circuit which is controlled by the associated signal repeater and approach lighting relays in such manner that this circuit will become closed when either of these relays becomes deenergized, and which includes the low resistance winding it! of the associated lightout relay. Each signal lamp L is also provided with a checking circuit which includes the high resistance winding 9 of the associated lightout relay, and which is closed at all times except when the lamp filament becomes broken or burned out. Referring particularly to lamp L of signal S the energizing circuit for this lamp passes from terminal X through the filament of lamp L wires 26 and 27, back contact 28 of relay SR. connected in multiple with back contact 29 of relay ALR Wire 35, winding IQ of relay LOR and wire 31 to terminal 0. The checking circuit for lamp L passes from terminal X through the filament of lamp L wire 26, resistor R and the winding 9 of lightout relay LOR to terminal 0. The parts are so proportioned that lamp L will become lighted when and only when the energizing circuit for the lamp is closed, but that, relay LOR will hold its front contacts closed when either the energizing or the checking circuit for lamp L is closed.

It should be pointed out that while, as shown in the drawings, each checking circuit includes a resistance R, this resistance can be omitted if the resistance of the high resistance winding is sufificiently high to prevent the filament of the associated lamp from becoming incandescent while the checking circuit in which the resistance is included is closed and the associated energizing circuit is open. It should also be pointed out that when the energizing circuit for a lamp is closed, the checking circuit is also closed, so that the current which is supplied to the lamp flows through the windings 9 and iii of the associated lightout relay in parallel. The windings 9 and I are so arranged that the fluxes set up in the relay when both of these windings are energized are cumulative.

As shown in the drawings, all parts are in their normal positions, that is to say, all relays are picked up, the winding 6 of each signal is supplied with current of normal polarity, so that the armatures of signals S and S both occupy their right-hand or proceed positions, and the lamps L and L are both extinguished.

In explaining the operation of the apparatus as a whole, I will first assume that a train moving in the direction of the arrow traverses the stretch of track shown in the drawings. When the train enters the block in rear of block AB,

the shunting of the track relay associated with this block will cause approach lighting relay ALE, to become deenergized and close its back contact 29. The closing of this contact will complete the energizing circuit for lamp L and this lamp will therefore become lighted and will cause signal S to display a proceed indication.

When the train enters block AB, track relay 'I'R will become deenergized, and will interrupt the circuit for winding 6 of signal S thus causing the mechanism of this signal to move to its stop position, and approach lighting relay ALR to become deenergized. When signal S moves to its stop position, it will interrupt the circuit which was previously closed for signal repeater relay SB and since both circuits for this relay will then be open, this relay will become deenergized. The deenergization of relay SR will cause the polarity of the current supplied to the circuit for the winding 6 of the signal for the block to the right of block A-B to become closed, and as a result, as soon as the train moves out of this block, this signal will move to its caution. position. The deenergization of relay SB will also cause this relay to complete, at its back contact 28, the energizing circuit for lamp L including this contact, so that when the approach lighting relay ALR picks up due to the train having passed out of the block tothe right of block AB, signal S will continue to display a stop indication. The deenergization of approach lighting relay ALR will cause the energizing circuit for lamp L of signal S to become closed, and this lamp will therefore become lighted, thus causing signal S to display a proceed indication.

When the train enters the block to the left of block AB, track relay TR will become deenergized and will cause winding 6 of signal S to become deenergized. The deenergization of winding 6 of signal S will cause the mechanism of this signal to move to its stop position, which movement, in turn, due to the resultant operation of the associated circuit controller, will deenergize signal repeater relay SR When relay SR becomes deenergized, it will reverse the polarity of the current supplied to the circuit for winding 6 of signal S but as long as any part of the train remains in block AB, the circuit for winding 6 will remain open at the front contacts of track relay TR and signal S will continue to display a stop indication. As soon, however, as the train passes completely out of block AB, the resultant energization of track relay TR. will complete the circuit for winding 6 of signal S and this signal will then move to its caution position. The movement of signal S to its caution position will complete the previously traced circuit for signal repeater relay SR including contacts T-l and 8-8 of the circuit controller of signal S and relay SB will then pick up. When this relay picks up, it will interrupt the energizing circuit for lamp L and will cause the winding 6 of the signal for the block to the left of block AB to be supplied with current of normal polarity, whereupon the mechanism of this signal will move to its proceed position.

When the train leaves the block to the left of block AB, track relay TR will pick up and will cause signal S to move to its caution position in the same manner that the picking up of track relay TR. caused signal S to move to its caution position. As soon as signal S reaches its caution position, signal repeater relay SR will pick up, whereupon signal lamp L will become extinguished, and the mechanism for signal S will move to its proceed position. When the train passes out of the second block in advance of block AB, signal S will move to its proceed position, and all parts will then be restored to the positions in which they are shown in the drawings.

I will now assume that with the parts in the positions in which they are shown in the drawings, the filament of lamp L becomes broken, and that a train subsequently enters the block to the right of point A. When the filament of lamp L becomes broken, the checking circuit for this lamp becomes interrupted at the lamp filament, and lightout relay LOl-t therefore becomes deenergized, and opens its front contact ll. The opening of this front contact will deenergize the winding 5 of signal S whereupon the signal mechanism of this signal will move to its stop position. When the mechanism of signal S moves to its stop position, signal repeater relay SR will become deenergized, and will reverse the polarity of the current supplied to winding 6 of signal S thus causing the mechanism of signal S to move to its caution position. As a result, when the train enters the block to the right of point A and causes approach lighting relay ALR to become deenergized and complete the circuit for lamp L signal S will indicate caution even though neither of the two blocks in advance of point A is occupied.

If signal S occupies its caution position instead of its proceed position when the filament of lamp L becomes broken, and a train subsequently enters the block to the right of point A, the operation of the apparatus will be similar in all respects to that just described. It will be seen, therefore, that with a signal system constructed in the manner described, if the filament of a signal, lamp becomes broken when the mecha nism of the signal in the rear occupies its proceed position, the mechanism of the signal in the rear will immediately move to its caution position, thus insuring that an engineman will not be required to pass a signal which indicates proceed, only to find the signal next in advance dark. Since the operating rules of railroads usually require that a dark signal be obeyed as a stop signal, the arrangement herein disclosed aids in removing the operating hazard of a sudden brake application resulting from an unexpected dark signal,

If the lamp of a signal burns out after it has .become lighted due to the presence of a train in the block immediately in rear of the signal, both the checking and energizing circuits for the lamp will become open, and the associated lightout relay will become deenergized, and will thus cause the signal mechanism to move to its step position. This is desirable because since the operating rules of railroads usually require that a dark signal be obeyed as a stop signal, and since the signal mechanism occupies its stop position, if any light from an extraneous source such, for example, as a locomotive headlight or the suns rays when the sun is close to the horizon, should enter the signal and be reflected back by the optical assembly of the signal, the resulting phantom indication would be a stop indication. The signal mechanism, after being moved to its stop position in the manner just described, will subsequently remain in its stop position until the burned out lamp is replaced, and the signal next in rear will be prevented from moving to its proceed position, even though trafilc conditions in advance are such that the mechanism of this signal would normally assume its proceed position.

Referring now to Fig. 2, in the modified form of the apparatus here illustrated, there is provided at each signal location, in addition to the apparatus shown in Fig. l, a transformer designated by the reference character T with a suitable distinguishing exponent, a power-off relay designated by the reference character POR with a suitable distinguishing exponent, and a standby or reserve source of power here shown as a battery designated by the reference character E with a distinguishing exponent. The primary winding 35 of each transformer T is constantly connected with the terminals Z and O of a suitable source of alternating current, not shown in the drawings, while the secondary winding 36 of each transformer T is constantly connected with the winding of the associated power-off relay. It will be seen, therefore, that each power-off relay will be energized at all times except in the event that the alternating current supply fails.

Each signal lamp L, as shown in Fig. 2, is provided with an energizing circuit which is closed when and only When the associated approach lighting relay ALR is deenergized and the associated signal repeater relay SR is energized, and with another energizing circuit which is closed whenever the associated signal repeater relay is deenergized regardless of whether the associated approach lighting relay is then energized or deenergized. Each of these energizing circuits includes the low resistance winding l of the associated light-out relay connected in multiple with a rectifier P, and is arranged to be supplied with either alternating current from the secondary winding 3'5 of the associated transformer T, or with direct current from the associated battery E, according as the associated poweroff relay POR is then energized or deenergized. Referring particularly to lamp L the one energizing circuit for this lamp normally passes from the right-hand terminal of transformer T through wire 31, front contact 3l338 of poweroff relay POR wires 39 and 40, back contact 29-2 9 of approach lighting relay ALR wire 41, front contact 42 'l2 of signal repeater relay SR wire 43, low resistance winding ID of lightout relay LOR connected in multiple with rectifier P wire 54, the filament of lamp L wires 45 and 66, front contact FL-4i of power-off relay POR and wire 48 to the left-hand terminal of transformer T while the other energiz- 7 ing circuit for this lamp normally passes from the right-hand terminal of transformer T through wire 37, front contact 3838 of poweroff relay POR wires 39 and 49, back contact 12-42 of signal repeater relay SR wire 43, the low resistance winding In of lightout relay LOR connected in multiple with asymmetric unit P wire 44, the filament of lamp L wires 35 and 46, front contact 4'l4l of power-off relay POR and wire 48 to the other terminal of transformer T When power-off relay POR becomes deenergized due to a power failure, each of the energizing circuits just traced includes battery E and back contacts 38-38 and 41-41 of power-oil relay POR in place of secondary winding 36 of transformer T wires 31 and 48, and front contacts 3838 and ll-41 of transformer T The function of the rectifier P in each of the circuits just traced is to enable the relay LOR to be of the direct current type, and at the same time cause it to become energized whenever either of the energizing circuits for lamp L are supplied with alternating current from the secondary winding 36 of transformer T The rectifier P also acts to render the relay slow releasing, which fact greatly facilitates the operation of the relay when the relay is supplied with alternating current.

Each signal lamp L, as shown in Fig. 2, is also provided with a checking circuit which is closed when and only when the associated approach lighting and signal repeater relays are both energized, and which includes both the low and high resistance windings of the associated lightout relay connected in series. Referring particularly to lamp L the checking circuit for this lamp passes from terminal X through the high resistance winding 9 of relay LOR wire 50, front contact 23-49 of approach lighting relay ALR wire 4|, front contact l2- l2= of signal repeater relay SR wire 43, the low resistance winding 10 of lightout relay LOR connected in multiple with asymmetric unit P wire 44, the filament of lamp L and wire 45 to terminal 0 of the source. The parts are so proportioned that when this circuit is closed, relay LOR will hold its front contact ll closed but that, the filament of lamp L will remain dark.

The remainder of the apparatus shown in Fig. 2 is similar in all respects to the corresponding apparatus shown in Fig. 1.

With the system modified in the manner shown in Fig. 2, it will be noted that the energizing circuit for each signal lamp including the back contact.29---29 of the associated approach lighting relay and the front contact i? l2 of the associated signal repeater relay will be closed when the block next in rear of the signal is occupied and the block next in advance is unoccupied, and that, the other energizing circuit for each lamp will be closed whenever the block next in advance of the signal is occupied. It will be apparent, therefore, that each signal lamp will normally become lighted when a train enters the block next in rear of the signal, and will subsequently remain lighted until the train passes completely out of the block next in advance of the signal. It will also be noted that with the system constructed in the manner shown in Fig. 2, when the block next in rear and the block next in advance of a signal are both unoccupied, the checking circuit for the associated lamp will be closed if the lamp filament is then. intact, but that, if the lamp filament is burned out, this checking circuit will then be open. As was pointed out hereinbefore, each lightout relay will hold its front contacts closed when either of the two energizing circuits or the checking circuit for the associated lamp is closed, but will open its front contact when all of these circuits are open, and it will be seen, therefore, that the apparatus illustrated in Fig. 2 will function in the same manner as the apparatus illustrated in Fig. 1 when a lamp filament becomes broken or burns out. The operation of the portion of the apparatus shown in Fig. 2 but not specifically described, is the same as the operation of the corresponding apparatus shown in Fig. 1, and it is believed to be unnecessary, therefore, to repeat the description of the operation of this portion of the apparatus.

Referring now to Figs. 3 and 3 the track rails l and l as here illustrated, are divided into blocks in the same manner as in the preceding views, three such blocks AB, BC, and CD, being shown complete in the drawings. Each of these blocks is provided with a track circuit in cluding a track battery 3 and a track relay TR. Located at the entrance end of each block is a signal designated by the reference character S with a distinguishing exponent,v each 'of which signals, as here shown, comprises two separate signal mechanisms each designated by the same reference character as the reference character for the associated signal with a distinguishing subscript. Each of these signal mechanisms is similar in all respects to the mechanism of the signals previously described, and in actual practice both mechanisms will usually be secured to the same pole or mast with the one mechanism disposed above the other mechanism. With this arrangement, when both mechanisms are displaying a red aspect, the signal indicates stop: when the upper mechanism displays a yellow aspect and the lower mechanism displays a red aspect. the signal indicates caution; when the upper mechanism displays a yellow aspect and the lower mechanism a green aspect, the signal indicates approach restricting; and when the upper mechanism displays a green aspect and the lower mechanism a red aspect, the signal indicates proceed.

Associated with each signal are a polarized distant relay designated by the reference character DR with a distinguishing exponent, an approach lighting relay designated by the reference character ALR with a distinguishing exponent, a lightout relay designated by the reference character LOB with a distinguishing exponent, a slowreleasing repeater relay designated by reference character SR with a distinguishing exponent; a power-off relay designated by the reference character POR with a distinguishing exponent, a transformer designated by the reference character T with a distinguishing exponent, a standby battery designated by the reference character E with a distinguishing exponent, and a reactor designated by the reference character F with a distinguishing exponent. Each reactor F has the same reactance as the low resistance winding N3 of the associated lightout relay for a reason which will become apparent as the description proceeds.

The energization of the winding 5 of each signal mechanism S1 controlled by the associated distant relay DR and by the associated track relay TR. Referr ng particularly to the winding 6 of signal mechanism S1; when track relay TR is energized and distant relay DR is energized in its normal direction. so that its polar contacts are swung towa rd the left. as shown in the drawings, this Winding is supplied with current of normal polarity over a circuit which passes from terminal X through front contact 55 of track relay TR wires 55 and 51, normal polar contact 58---58 of distant relay DR Wire 59, front contact 5!l!l of distant relay DR winding 6 of signal mechanism 81 front contact tit-6i of distant relay DR wire normal polar contact 53-51% of d stant relay DR w res t l and 65, and front contact 66 of track relay TR to terminal 0. When, however. track relay TR is energized and distal": relay DR is energized in its reverse direction so that its polar contacts are swung toward the right, winding 5 of signal mechanism 81 is then supplied with current of reverse polarity over a circuit which passes from terminal X through front contact 55 of track relay TR wires 56 and 5?, reverse polar contact til-63 of distant relay DR wire 52, front contact 6i--El of distant relay DR winding 5 of signal mechanism S1 front contact (511 60 of distant relay DR wire 59, reverse polar contact 53-438 of distant relay DR wires til, 68, 5i and 65, and front contact 66 of track relay TR to terminal 0. When track relay TR is energized and distant relay DR is deenergized, winding 8 of signal mechanism 81 is then supplied with current of reverse polarity over a circuit which passes from terminal X through front contact 55 of track relay TR wire 5%, back contact 6l-5l of distant relay DR winding 5 of signal mechanism 81 back contact iiil6$ of distant relay DR wire 65, and front contact 66 of track relay TR to terminal 0. When winding 6 of signal mechanism SIA is supplied with current of normal polarity this signal mechanism will, of course, occupy the position in which the green roundel G is disposed in front of the associated lamp L, and when winding 6 of this signal mechanism is supplied with current of reverse polarity, this signal mechanism will occupy the position in which the yellow roundel Y is disposed in front of the associated lamp L.

The winding 6 of each signal mechanism S2 is controlled by the associated distant relay DR, by the associated track relay TR, by the associated lightout relay LOR, and by the circuit controller of the associated signal mechanism S1. Referring particularly to winding 6 of signal mechanism S1, this winding is provided with a circuit which passes from terminal X through front contact 55 of track relay TR wires 56 and E i, contact t-t of the circuit controller of signal mechanism S1 wire i2, contact ?-l of the circuit controller of signal mechanism S1 wire 13, front contact id of distant relay DR wire 15, reverse polar contact 76 of distant relay DR wire TE, front contact ll of light-out relay LOR wire 38, winding 6 of signal mechanism Sz front contact 80 of distant relay DR wire 8 5, reverse polar contact 82 of distant relay DR wires 62%, 6-; and 65, and front contact 66 of track relay TR to terminal 0. This circuit is closed only when track relay TR, and lightout relay LOR are both energized. distant relay DR is energized in the reverse direction, and signal mechanism S1 is swung to its left-hand extreme position; and the current supplied to winding 6 of signal mechanism S23 over this circuit is of such polarity that when this circuit is closed the signal mechanism will be swung to the position in which the green roundel is in front of the associated lamp.

Each signal repeater relay is controlled by the associated signal mechanisms S1 and S2, by the associated lighto-ut relay LOR, by the associated distant relay DR and by the associated track relay TR. Referring particularly to signal repeater relay SR one circuit for this relay is closed when signal mechanism S1 occupies its caution position, signal mechanism S2 occupies its proceed position, light-out relay LOR is ener gized, distant relay DR is energized in its reverse direction, and track relay TR is energized. This circuit passes from terminal X through front contact 55 of track relay TR wires 56 and H, contact 88 of the circuit controller of signal mechanism S1 wire 12, contact 'i'l of the circuit controller of signal mechanism S1 wire, 13, front contact E4 of distant relay DR wire 15,

reverse polar contact l6 of distant relay DR wire Ti, front contact IT of lightout relay LOR wire l8, contact l-l of the circuit controller of signal mechanism S2 Wire 83, and the winding of relay SR to terminal 0. Another circuit for relay SR is closed when track relay TR is energized, signal mechanism S1 occupies its proceed position and signal mechanism 82 occupies its stop position, this latter circuit passing from terminal X through front contact 55 of track relay TR wires 55 and if, contact 'I-'I of the circuit controller of signal S1 wire 12, contact 8-3? of the circuit controller of signal mechanism 81 Wire 8 5, contact 88 of signal mechanism S2 wire 85, contact 'I7 of signal mechanism S2 wire 83, and the winding of signal repeater relay SE to terminal 0.

Each powerofi relay POR is controlled in the same manner as in Fig. 2, and the control of this relay need not, therefore, be repeated.

Each distant relay DR is controlled by the associated track relay TR, by the signal repeater relay SR associated with signal S next in advance, by the circuit controller of the signal mechanism S1 of the signal next in advance, and by the track relay TR for the second block in advance of the associated signal. Referring particularly to relay DR for example, one circuit for this relay passes from terminal X through contact 55 of track relay TR Wires 56 and 'H, contact 8-5? of signal mechanism, S1 of signal S wire 89, the winding of relay ALR wire 81, front contact 88-38% of signal repeater relay SR wire 39, front contact 99 of track relay TR wire 9!, the Winding of relay DR wire 92, front contact 93-93 of signal repeater relay SR Wire 94, and front contact 95 of track relay TR to terminal 0. Another circuit for relay DR is similar to the circuit just traced with the exception that this latter circuit includes back contacts EEG-98 and 9393' of signal repeater relay SR instead of front contacts 88-88 and 9993 of signal repeater relay SE A third circuit for distant relay IR is similar to the circuit first traced for this relay with the exception that this latter circuit includes contact l -E of signal mechanism S1 and wire 72 in place of wire ii and contact 8-8 signal mechanism. S1

It will be noted that each of the circuits for each distant relay includes the approach lighting relay associated with the signal next in advance, and it follows, therefore, that each approach lighting relay will be energized whenever the distant relay next in rear is energized.

Each lamp L1 is provided with two energizing circuits one of which is closed when the associated approach lighting relay is deenergized and the associated signal repeater relay is energized, and the other of which is closed when the associated signal repeater relay is deenerglzed, regardless of whether the associated approach lighting relay is energized or deenergized. Each of these energizing circuits includes the low resistance winding II] of the associated light-out relay connected in multiple with an asymmetric unit P, and each of these circuits is arranged to be supplied with alternating current from the secondary winding 36 of the associated transformer T, or with direct current from the associated battery B according as the power-off relay POR is energized or deenergized. Referring particularly to lamp L1 the one energizing circuit for this lamp normally passes from the lefthand terminal of transformer T through front contact dB--38 of power-01f relay POR wires 95, 99 and 97., back contact 98 of approach lighting relay ALR wire 99, front contact map-les of signal repeater relay SR wire IBI, the low resistance winding II) of lightout relay LOR connected in multiple with asymmetric unit P wire I92, the filament of lamp: L1 wires I93 and I94, and front contact 3'I l1 of power-off relay POR to the other terminal of transformer T The other energizing circuit for lamp L1 normally passes from the left-hand terminal of transformer T through front contact fill-33 of relay POR wires 95 and 96, back contact IllIlIll9 of signal repeater relay SR wire lilI, the low resistance winding I9 of lightout relay LOR connected in multiple with asymmetric unit P wire I02, the filament of lamp L1 wires I03 and I94, and front contact 4'I4l of poweroff relay POR to the other terminal of secondary winding 36 of transformer T When, however, power-01f relay POR is deenergized, each of the energizing circuits just traced instead of being supplied with alternating current from the secondary winding 39 of the transformer over front contacts 4'I4'I and 3838 of power-off relay POR are supplied with direct current from battery E over back contacts 3833" and 9'I4'i of power-off relay POR Each lamp L1 is also provided with a checking circuit which is closed when the associated approach lighting and signal repeating relays are both energized provided the filament of the lamp is then intact. Referring particularly to lamp L1 the checking circuit for this lamp may be traced from terminal K through the high resistance winding 9 of lightout relay LOR Wire H35, front contact 9E3-9Ei of approach lighting relay ALR wire 99, front contact Hit-499 of signal repeater relay SR wire lei, the low re sistance winding I9 of lightout relay LOR connected in multiple with rectifier P wire I 82, the filament of lamp L1 and wire I93 to terminal 0. It will be noted that the low resistance winding I9 and the high resistance winding 9 of the lightout relay LOR are connected in series in this checking circuit. The windings 9 and it are so arranged that the fluxes set up in the core of relay LOR. when, this circuit is closed will be cumulative, and the parts are so proportioned that when this circuit is closed relay LOR will maintain its front contact I! closed.

Each lamp L2 is likewise provided with two energizing circuits, each of which is arranged to be supplied with alternating current from the secondary winding 36 of the associated transformer T, or with direct current from the associated battery B according as the associated power-off relay is energized or deenergized. Referring particularly to lamp L2 the one circuit for this lamp is closed only when approach lighting relay ALR is deenergized, and normally passes from the left-hand terminal of transformer T through front contact 3838 of power-off relay POR wires 95, 99, and 9?, back contact I08 of approach lighting relay ALR reactor F the filament of lamp Lz wire I06, and front contact il ll of power-off relay POR to the right-hand terminal of transformer T The other energizing circuit for the lamp L2 is closed when and only when the signal repeater relay SR is deenergized, and normally passes from the left-hand terminal of the secondary winding 36 of transformer T through front contact 38-438 of power-off relay POR wire 95, back contact I69 of signal repeater relay SR Wire H0, reactor F the filament of lamp L2 wire I06 and front contact 41-41 of poweroff relay POR to the other terminal of the secondary winding 36 of transformer T When the power-off relay POR is deenergized, each of the circuits just traced for lamp L2 are then connected with battery E instead of with the secondary winding 36 of transformer T3 in a manner which will be readily understood from an inspection of the drawings, without further description.

It will be noted that each of the circuits for the lamp L2 includes the reactor F which, as was previously pointed out, has the same reactance as the low resistance winding ID of the associated lightout relay LOR It will further be noted that the circuits for the lamp Lz are supplied with energy from the same source as the corresponding circuits for the lamp L1, and since each of the energizing circuits for the lamp L1 includes the low resistance winding I!) of the associated lightout relay, it follows that both lamps will be supplied with current of the same magnitude. 7

As shown in the drawings, blocks A--B, B-C and -D are all unoccupied, but the block to the left of point D is occupied by a train W. Track relays TR TR and TR are therefore all energized, but track relay TR is deenergized. With track relay TR deenergized, all circuits for the winding 6 of signal mechanism S1 are interrupted at the front contacts 56 and 66 of this track relay, and the sole circuit for the winding ii of signal mechanism S2 is likewise interrupted at the front contacts 56 and 66 of this track relay,

with the result that the red roundel of both signal mechanisms S1 and S2 is disposed in front of the associated lamps L1 and Lz Furthermore, with track relay TR deenergized, all circuits for relays ALR SR DR and DR are open so that these relays are all deenergized. The power-off relays POR are all energized, and since the power-off relay FOR is energized and signal repeater relay SR is deenergized, the energizing circuit for lamp L1 including the back contact lllfl-lllfl of signal repeater relay SR and secondary winding 36 of transformer T is closed, and both circuits for lamp Lz including the secondary winding 36 of transformer T are closed, so that lamps L1 and L2 both lighted. Signal S therefore indicates stop. Lightout relay LOR is energized by virtue of the energizing circuit which is closed for lamp Ll so that its front contact I1 is closed.

Track relay TR. being energized and distant relay DR being deenergized, winding 8 of signal mechanism S1 is supplied with current of reverse polarity, and winding of signal mecha nism S2 is deenergized. The yellow roundel of signal mechanism S1 is therefore disposed in front of the associated lamp L1 and the red roundel of signal mechanism S2 is disposed in front of the lamp L2 With the signal mechanisms S1 and S2 in the positions just described, all circuits for signal repeater relay SR are open, and this relay is therefore deenergized. Since relay SR, is deenergized, the energizing circuit for lamp L1 including back contact Hill-9953 of this relay, is closed and the energizing circuit for lamp L2 including back contact [Q9 of relay SR, is closed. The lamps L1 and L2 are therefore both lighted, and signal S therefore displays a caution indication. Since track relay TR is energized and signal mechanism S1 occupies its caution position and signal repeater relay SR is deenergized and track relay TR is energized, distant relay BB is supplied with current of reverse polarity, and approach lighting relay ALR is energized. Furthermore, since the one energizing circuit for lamp L1 is closed lightout relay LOl't is also energized.

With distant relay DR energized in the reverse direction and track relay TR energized, winding 6 of signal S1 is supplied with current of reverse polarity, and winding 6 of signal mechanism S2 is supplied with current of normal polarity. Signal mechanism S1 therefore occupies its extreme left-hand position in which the yellow roundel Y of this mechanism is disposed in front of the lamp L1 and signal mechanism Sz occupies its extreme right-hand position in which the green roundel G of this mechanism is disposed in front of the lamp Lz Signal mechanisms S1 and S2 being in the positions just described, s gnal repeater relay SR is energized and since track relay TR is also energized distant relay DR is energized in the normal direction and approach lighting relay ALR is also energized. Approach lighting relay ALR and signal repeater relay SR both being energized, the checking circuit for lamp L1 is closed, and lamp L1 is therefore deenergized, but lightout relay LOR is energized. Both circuits for lamp L2 are open, and this lamp is therefore also deenergized.

' Distant relay DR. being energized in its normal direction, winding 6 of signal mechanism Sl is supplied with current of normal polarity so that the green roundel of this signal mechanism is disposed in front of the lamp L1 Furthermore. winding 5 of signal mechanism 82* is deener gized, so that the red roundel of this mechanism is in front of lamp L2 Approach lighting relay ALE. is energized and signal repeater relay SR is also energized. All energizing circuits for the lamps L1 and Lz are therefore open so that these lamps are deenergized and the checking circuit for lamp LIA is therefore closed so that lightout relay LOR is energized.

With the apparatus in the positions just described when the train W passes out of the section, to the left of point D, track relay 1R will pick up and will close its front contacts. When front contacts 55 and 66 of track relay 'I'R become closed, a circuit for winding 6 of signal mechanism S1 3 including these contacts and back contacts Gil-45 and Gil-M of distant relay DR will become closed, and signal mechanism S1 will therefore move to its right-hand extreme position in which the yellow roundel Y is disposed in front of the lamp L1 As soon as the signal mechanism S1 reaches this posit on. con tact 88 of this mechanism will become closed, and will complete one of the circuits for the distant relay DR thus causing this relay to become energized in its reverse direction. and approach lighting relay ALR to p ck up. The picking up of a roac li h ing relay .AIR under these conditions will have no immediate effect on the remainder of the apparatus because signal repeater relay SR will still remain deenergized, and as long as this relay remains deener ized the lamps LP and L2 will remain lighted by virtue of the energizing circuits for these lamps controlled by relay SR When distant relay DR, becomes energized in its reverse direction in the manner just described. the reverse energizing circuit for winding '5 of signal mechanism S1 including back contacts interrupted, and another circuit for winding t of signal mechanism S1 including front contacts BIL-St and (SI-45! of relay DR will become closed. Signal mechanism SIC will remain in the position shown, however, because the current supplied to the winding 5 of this mechanism over both of these circuits flows through the winding in the same direction. The energization of distant relay DR, under the conditions just described also completes the circuit for winding 6 of signal mechanism S2 and when this circuit becomes closed the mechanism S2 will move to its extreme right-hand position in which the green roundel is disposed in front of the lamp L2 The movement of the signal S2 to the position just described completes one of the circuits for signal repeater relay SR", and relay SR therefore picks up and reverses the polarity of the current supplied to distant relay DR thus causing this relay tobecome energized in its normal condition. The picking up of relay SR also interrupts the energizing circuits which were previously closed for the lamps L1 and L2 and completes the checking circuit for lamp L1 The lamps L1 and L2 therefore both become extinguished, but relay LOR will remain energized for reasons which will be readily understood from the foregoing description.

When relay DR becomes energized in its normal direction, it interrupts a circuit which was previously closed for winding 6 of signal mechanism S1 and completes another circuit for this mechanism, thus causing this mechanism to move from the position in which the yellow roundel Y is in front of the lamp L1 to the position in which the green roundel G is disposed in front of the lamp L1 The energization of the relay DR in its normal direction also interrupts, at its polar contacts, the circuit which was previously closed for winding 6 of signal mechanism S2 and this latter mechanism therefore moves from the position in which the green roundel is disposed in front of the lamp L2 to the position in which the red roundel R is disposed in front of the lamp L2 The movement of the two signal mechanisms S1 and S2 from the positions in which they are shown in, the drawings to the position just described interrupts one circuit for repeater relay SR and completes another circuit for this relay, but due to the slow releasing characteristics of relay SR this relay does not open its front contact under these conditions.

I will now assume that the parts are in the positions in which they are shown in the drawmas and that the filament of amp L1 becomes interrupted for some reason. Under these conditions, the checking circuit for lamp L1 will, of course, become interrupted at the lamp filament, and lightout relay LOR will therefore become deenergized and will open its front contact ii. The opening of this contact will cause winding 5 of signal mechanism S2 to become deenergized, and when this winding becomes deenergized, signal mechanism S2 will move to the position in which the red roundel R is disposed in front of the associated lamp Lz thereby interrupting the circuit for signal repeater relay SE and, hence, causing this latter relay to become deenergized, The deenergization of relay SR in turn, will cause lamp L2 to become lighted, so that the lower mechanism of this signal will now display what is usually regarded as a stop aspect. The deenergization of relay SR will also reverse the polarity of the current supplied to distant relay DR and as a result, the mechanism SIA of signal S will move from the position shown to the position in which the yellow roundel Y is disposed in front of the lamp L1 As soon as the mechanism reaches this latter position, the circuit for the winding 5 of the mechanism Sz will become closed and will cause the mechanism S2 to move to the position in which the green roundel is in front of the lampLz It will be seen, therefore, that if a train new enters the block to the right of signal'S this signal will display a caution indication rather than a proceed indication, and the train will therefore be prepared to stop when it reaches signal S ,,thus preventing the undesirable condition of having the train pass a signal which indicates proceed or approach restricting, only to be required to stop at the next signal.

It should be particularly pointed out that in signal systems of the type shown in Fig. 3, as they have heretofore generally been constructed, it has been customary to employ in place of the two winding lightout relays LOR, a single winding lightout relay which was normally deenergized but which became energized when the lamp of the upper signal mechanism S1 became lighted, and to include in the control circuit for the winding 6 of the lower signal mechanism, in addition to a front contact of the lightout relay corresponding to the contact ll in the drawings, a front contact of the approach lighting relay which latter contact was connected in multiple with the front contact of the lightout relay, and which served to maintain the circuit for the winding 6 of the lower signal mechanism closed under the proper trafiic conditions, even though the signal was then dark. With this arrangement, when a train approached the signal while the circuit for the winding 6 of the lower mechanism was closed, the resultant deenergization of the associated approach lighting relay caused the circuit for the winding 6 to become interrupted during the interval of time which elapsed between the opening of the front contacts of the approach lighting relay and the closing of the front contacts of the lightout relay, and this interruption of the circuit for the winding 5 permitted the lower signal mechanism to start to return to its stop position, with the result that this lower mechanism sometimes gave a momentary red blink. This blink is undesirable, and with my present invention, due to the fact that each lightout relay is energized regardless of whether the signal is dark or lighted as long as the lamp filament of the upper signal mechanism is intact, and to the further fact that the rectifier P which is connected in multiple with the low resistance winding In of the lightout relay renders the lightout relay slow releasing, completely eliminates this undesirable blink.

Under some conditions it is desirable to so con trol the signals of a system such as that shown in Figs. 3 and 3*, that, if the filament of the lamp for the upper mechanism S1 of a signal becomes interrupted for any reason at any time except when the associated signal is displaying a stop indication, both mechanisms of such signal will immediately move to the positions which these mechanisms occupy when the signal is displaying a stop indication, and the mechanisms of each of the signals in the rear of such signal will move to the positions that these latter mechanisms would normally occupy when the signal having the burned out lamp is displaying a stop indication. This result may be accomplished by modifying the control circuits at each signal location in the manner shown in connection with location A in Fig. 4. Referring to Fig. 4, as here shown,

the lightout relay LOR, has been provided with an additional front contact Ill, and this contact together with the contact H has been included in all those circuits which are controlled by the track relay TR with the exception of the circuit for relay DR With the circuits modified in this manner, if the filament of lamp L1 becomes interrupted for any reason, lightout relay LOR will, of course, become deenergized, and as a result, if the winding 6 of each of the signal mechanisms S1 and Sz is not already deenergized, it will become deenergized, thus causing both of these mechanisms to move to the position in which the red roundel of the mechanism is in front of the associated lamp. Furthermore, if

. signal repeater relay SR and approach lighting relay ALR, are not already deenergized, these relays will become deenergized due to the movement of the signal mechanisms and will thus cause the lamp Lz to become energized and the mechanisms of the two signals next in rear of signal S to move to the positions which these last named mechanisms normally occupy when signal S is displaying a stop indication.

Referring now to Figs. 5 and 5*, as here shown, each block is provided, in place of the searchlight type of signals shown in Figs. 3 and 3, with a color light signal comprising an upper unit U made up of a green lamp G, a yellow lamp Y, and a red lamp R, and a lower unit L made up of a green lamp G and a red lamp R. When the red lamps of both units of a signal are lighted, the signal indicates stop; when the yellow lamp of the upper unit and the red lamp of the lower unit are both lighted, the signal indicates caution; when the yellow lamp of the upper unit and the green lamp of the lower unit are lighted, the signal indicates approach restricting; and when the green lamp of the upper unit and the red lamp of the yellow unit are both lighted, the signal indicates proceed. The relays and other apparatus shown in Figs. 5 and 5 are similar to those shown in Figs. 3 and 3 with the exception that no signal repeater relays are provided as in Figs. 3 and 3 since these relays are unnecessary with the type of signals shown in Figs. 5 and 5 Each distant relay as shown in Figs. 5 and 5 is controlled by the associated track relay TR, by the distant relay DR for the signal next in advance and by the track relay associated with the signal next in advance over a polarized line circuit which is supplied with current of normal or reverse polarity according as the distant relay for the signal next in advance is picked up or released, and which includes the winding of the approach lighting relay for the signal next in advance. Referring particularly to distant relay DR when track relays TR and TR are both energized and distant relay DR is'also energized, the polarized line circuit for this relay passes from terminal X through the winding of approach lighting relay ALR wire I20, front contact I2I of track relay TR front contact I23--I23 of distant relay DR line wire I24, front contact I25 of track relay TR the winding of distant relay DR, front contact I26 of track relay TR", line wire I21, and front contact I'M-I28 of distant relay DR to terminal '0. When, however, track relays TR and TR are both energized and distant relay DR is deenergized, this circuit then includes back contacts I23-I23 and I28--I28 of distant relay DR in place of front contacts I23---I23 and I28--I28 of distant relay DR It will be seen,

therefore, that when track relays TR and TR and. distant relay DR are all energized, distant relay DR will be supplied with current of normal polarity and that when track relays TR and TR are both energized and distant relay DR is deenergized, distant relay DR will be supplied with current of reverse polarity; but

that, when either track relay TR or track relay TR is deenergized, distant relay DR" will be deenergized.

It should be noted that since the circuit for each distant relay includes the winding of the approach lighting relay for the signal next in advance, each approach lighting relay will be energized or deenergized according as the distant relay for the signal next in rear is energized or deenergized.

Each power-off relay POR is controlled in the same manner as in the preceding views, and the control of these relays need not, therefore, be repeated.

The signal lamp G of the upper unit U of each signal S is provided with an energizing circuit which is supplied with alternating or direct current according as the associated power-off relay is energized or deenergized, and which is closed when and only when the associated approach lighting relay ALR is deenergized and the associated distant relay is energized in its normal direction. Referring particularly to the lamp G of the upper unit U of the signal S for example, the circuit for this lamp normally passes from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact I'I-- II of power-off relay POR wires I28 and I35, the low resistance winding II) of lightout relay LOR connected in multiple with asymmetric unit P wire E36, front contact I3'I'--I3I of track relay TR wire I38, front contact I39I39 of distant relay DR wire I40, back contact Nil-I41 of approach lighting relay ALR normal polar contact I i2---I42 of distant relay DR wire I43, the filament of lamp G, wire I44, back contact IRE-445 of approach lighting relay ALR wires I46, I47, I48 and E49, front contact 38--38 of power-off relay POR and wire 37 to the other terminal of the secondary winding 36 of transformer T When power-off relay FOR is deenergized, the circuit for lamp G then includes battery E and back contacts 41-41 and 38 m; of power-off relay POR in place of secondary winding 36 of transformer T and front contacts 4'I-- II and 38-43 of power-off relay POR The lamp G of the upper unit U of each signal S is also provided with a checking circuit which is closed when and only when the associated approach lighting relay ALR is energized and the associated distant relay DR is energized in its normal direction, and which includes the high resistance winding 9 of the associated lightout relay LOR. Referring particularly to the lamp Gof the upper unit U of the signal S for example, the checking circuit for the lamp G of this signal passes from terminal X through the high resistance winding 9 of lightout relay LOR front contact I4II4l of approach lighting relay ALR polar contact fi m-I42 of distant relay DR wire I43, the filament of lamp G of the upper unit U of signal S wires I44 and I50, and front contact kit's-I45 of approach lighting relay ALR to terminal 0.

It will be noted that the energizing circuit for the lamp G of the upper unit U of each signal S includes the W resistance Winding ID of the 33 of power-off relay POR associated lightout relay LOR, while the checking circuit for the lamp G of the upper unit U of each signal S includes the high resistance winding 9 of the associated lightout relay. The parts are so proportioned that when either of these circuits is closed, the associated lightout relay will hold its front contacts closed.

The lampY of the upper unit U of each signal S is provided with a first energizing circuit which is supplied with alternating current from the secondary winding 36 of the associated transformer 'I or with direct current from the associated standby battery E according as the associated power-off relay POR is energized or deenergized, and which is closed when and only when the associated distant relay DR is energized in its reverse direction, the associated track relay TR is energized, and the associated approach lighting relay ALR is deenergized. The signal lamp Y of the upper unit U of each signal S is also provided with a second energizing circuit which is likewise supplied with alternating current from the secondary'winding 36 of the associated transformer T or with direct current from the associated standby battery E according as the associated-power-ofi" relay POR is energized or deenergized, and which is closed when and only when the associated distant relay DR is deenergized, and the associated track relay TR is energized. Referring particularly to the lamp Y of the upper unit U of signal S when the poweroif relay POR is energized, the first energizing circuit may be traced from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact 4'I II' of power-off relay POR Wires I28 and I35, the low resistance winding ill of lightout relay LOR connected in multiple with asymmetric unit P wire I36, front contact I 3'I--I3'I of track relay TR wire I38, front contact I3-I39 of distant relay DR wire I40, back contact I III II of approach lighting relay ALR reverse polar contact 32-442 of distant relay DR wires II and I52, the filament of lamp Y, wire I53, front contact I5 iI5 of distant relay DR wire I50, back contact i 45-4 45 of approach lighting relay ALR wires I46, I41, I48 and I49, front contact 38'-38 of power-off relay PCB, and wire 37' to the right-hand terminalof secondary winding 3% of transformer T When power-off relay POR is deenergized, the circuit for lamp G then includes the standby battery E and back contacts 41 il and 38-3Ii of power-ofi relay POR in place ofthe secondary winding 36 of transformer T and front contacts 47-41 and 38- The second energizing circuit for lamp Y of the upper unit U of signal S when power-on relay POR is energized, may be traced from the left-hand terminal of secondary winding 36 of transformer T through wire 48, front contact 31-41 of poweroff relay POR wires I28 and I35, the low resistance winding IE2 of the lightout relay LOR connected in multiple with asymmetric unit P wire I36, front contact I3'L I3I of track relay TR wire I38, back contact I39I3!l of distant relay DRF, wire I52, the filament of lamp Y, wire I53, back contact I54-I54b of distant relay DR wires MT, I58 and I49, front contact 38'-38=- of power-off relay POR and wire 31130 the other terminal of the secondary winding 36 of transformer T When, however, power-off relay POR is deenergized, this circuitthenincludes the battery E and back contacts 3838 and :I'I-4'I of power-off relay POR in place offront' contacts 3838* and 4.I---1-'I of power-off relay FOR and secondary Winding 35 of transformer T The lamp Y of the upper unit U of each signal S is also provided with a checking circuit which is closed when and only when the associated approach lighting relay ALR is energized and the associated distant relay DR is energized in its reverse direction, and which includes the high resistance winding 9 of the associated lightout relay LOR. Referring particularly to the lamp Y of the upper unit U of signal S the checking circuit for this lamp passes from terminal X through winding 9 of lightout relay LOR front contact I II-I lI of approach lighting relay ALR reverse polar Contact I i2---Il2 of distant relay DR wires I5I and I52, the filament of lamp Y, wire I53, front contact I54-I54 of distant relay DR Wire I50, and front contact I45- I 45 of approach lighting relay ALR to terminal 0.

It will be noted that the two energizing circuits for the lamp Y of each unit U of each signal include the low resistance winding Ill of the associated lightout relay LOR, while thechecking clrcuit for such lamp includes the high resistance winding 9 of the associated lightout relay LOR. It will be apparent, therefore, that when either of the energizing circuits or the checking circuit for a lamp Y is closed, the associated lightout relay LOR will be energized.

The lamp R of the upper unit U of each signal S is provided with an energizing circuit which is supplied with alternating current from the secondary winding 35 of the associated transformer T, or with direct current from the associated standby battery E, according as the associated power-off relay POR is energized or deenergized, and which is closed whenever the associated track relay TR and the associated approach lighting relay ALR are both deenergized. Referring particularly to signal S the energizing circuit for the lamp R of the upper unit U of this signal may be traced from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact ilii of power-off relay POR wires I28 and I35, the low resistance winding ID of lightout relay LOR connected in multiple with asymmetric unit P wire I35, back'contact I31- I3? of track relay TR wire I55, the filament of lamp R, wires i5i, i 58 and I49, front contact 3833 of power-off relay POR and wire 31 to the other terminal of the secondary winding 36 of transformer T When the power-oif relay POR is deenergized, this circuit then includes battery E and the back contacts of power-01f relay POR instead of the secondary winding 36 of transformer T and the front contacts of power-off relay POR It will be apparent that this circuit also includes the low resistance winding I i! of the associated lightout relay so that when this circuit is closed the associated lightout relay will also be energized.

The green lamp G of the lower unit L of each signal S isprovided with an energizing circuit which is supplied with alternating current from the secondary winding36 of the asociated transformer T, or with direct current from the associated standby battery E according as the associated-power-oif relay POR is energized or deenergized, and which is closed when and only when the associated distant relay DR is energized in its reverse direction, the associated lightout relay LOR is energized, and the associated approach lighting relay ALR is deenergized. Referring particularly to signal S the circuit'for the lampdl G of the lower unit L of this signal when powerofi relay POR is energized may be traced from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact II4'I of power-off relay POR wire I28, a reactor F having the same impedance as the low resistance winding Ill of the associated light-' out relay LOR front contact Ii-lIl'I3[l of distant relay DR wire I3I, back contact 532 of approach lighting relay ALR reverse polar contact I33-I33 of distant relay DR wire I58, front contact I59I5ll of lightout relay LOR wire I60, the filament of lamp G, wire I49, front contact 3838 of power-off relay POR and wire 31 to the other terminal of the secondary winding 36 of transformer T When power-off relay POR is deenergized, battery E is included in the circuit just traced in place of the secondary winding 35 of transformer T in a manner which will be readily understood from an inspection of the drawings and from the foregoing description without further detailed description.

The red lamp R of the lower unit L of each signal S is provided with two energizing circuits. Referring particularly to signal S the one energizing circuit for the lamp R of the lower unit L of this signal is closed when and only when the associated distant relay DR is deenergized, and normally passes from the left-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact itll of power-off relay POR wire I28, reactor F back contact ISL-I36 of distant relay DR wire I55, the filament of lamp R, wire I49, front contact 38-48 of power-off relay POR and wire 3'? to the right-hand terminal of the secondary winding 36 of transformer T The other energizing circuit for the lamp R of the lower unit L of signal S is closed when distant relay DR is energized in its normal direction and approach lighting relay ALR is deenergized, and normally passes from the right-hand terminal of the secondary winding 36 of transformer T through wire 48, front contact llll of power-off relay POR wire I28, reactor F front contact I3il-I30 of distant relay DR wire I3I, back contact I32 of approach lighting relay ALR normal'contact i3il----I33 of distant relay DR wires I34 and IE5, the filament of lamp R, wire I49, front contact 3833* of power-off relay POR and wire 31 to therignt-hand terminal of the secondary winding 38 of transformer T When power-off relay POR is deenergized, each of the circuits just traced for the lamp R of the lower'unlt L of signal S is then supplied with current from battery E instead of from secondary winding 36 of transformer T in a manner which will be obvious from. an inspection of the drawings. The energizing circuits for the lamps R of the lower units L of each of the remaining signals are similar to those just traced for the lamp R of the lower unit L of the signal S As shown in the drawings, sections A-B, B-C

and CD are all unoccupied but the section to the left of point D is occupied by a train W. Track relays TR TR and TR are therefore all energized, but track relay TR is deenergized. The power-off relays POR are all energized. Since track relay TR is deenergized, the circuit for distant relay DR is open at front contacts I25 and I26 of track relay TR and the circuit for distant relay DR is open at front contact I2I of track relay TR Distant relays DR and DR are, therefore, both deenergized, and approach lighting relay ALR is also deenergized. The circuit for the lamp R of the upper unit U of signal S including back contact I3II3I of track relay TR is therefore closed, so that this lamp is lighted, and the circuit for the lamp R of the lower unit L of signal S including back contact I3B-I3il of distant relay DR is also closed, so that this lamp is also lighted. Signal S is, therefore, displaying a stop indication.

Furthermore, since lamp R of upper unit U of signal S is lighted, lightout relay LOR is picked up.

Track relay TR being energized and distant relay DR being deenergized, the circuit for lamp Y of signal S including front contact I3I--I3'I of track relay TR and back contacts I54--I5 l and I3I)--I3!l of distant relay DR is closed, so that lamp Y of this signal is lighted. Furthermore, since distant relay DR is deenergized the circuit for lamp R of the lower unit L of signal S including back contact Mil-43G of distant relay DR is closed, and this lamp is therefore also lighted. Signal S accordingly indicates caution. Lightout relay LOR is energized by virtue of the circuit for lamp Y of signal S". Distant relay DR is supplied with current of reverse polarity and approach lighting relay ALR is also energized.

Distant relay DR being energized in its reverse direction, and track relays TR and TR both being energized, distant relay DR is energized in its normal direction, and approach lighting relay ALR is therefore also energized. Since relays DR and ALR are both energized, all circuits for the lamps of signal S are open, and these lamps are therefore all dark. The checking circuit for lamp Y of the upper unit U of signal S is closed, however, and lightout relay LOR is therefore also energized. All relays at location A are energized, and all lamps of signals S are accordingly extinguished.

I will now assume that the parts are in the positions just described, and that a train moving toward the left enters section A-B. When the train enters section AB, approach lighting relay ALR will be deenergized due'to the previous deenergization of the track relay for the section to the right of point A, and the upper green lamp and the lower red lamp of signal S will therefore be lighted. The entrance of the train into section A-B will deenergize track relay TR and the deenergization of this track relay, in turn, will interrupt the circuit over which distant relay DR was previously energized, so that this relay will become deenergized. The deenergization of distant relay DR will interrupt the circuits which were previously closed for the upper green lamp and the lower red lamp of signal S and will complete the energizing circuit for the upper red lamp R of signal S and another energizing circuit for the lower red lamp of signal S The upper green lamp of signal S will therefore become extinguished and the upper red lamp will become lighted, while the lower red lamp will remain lighted, thus causing signal S to display a stop indication. It should be noted that during the interval which elapses between the interrupting of the circuit for the upper green lamp G of signal S and the closing of the circuit for the upper red lamp of this signal, lightout relay LOR will become momentarily deenergized. This relay, however, is rendered sufiiciently slow releasing by the asymmetric unit P to prevent its front contact opening and its back contact closing under these conditions.

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