US2096832A

US2096832A - Centralized traffic controlling system

Info

Publication number: US2096832A
Application number: US500802A
Authority: US
Inventors: Walter W Wenholz
Original assignee: General Railway Signal Co
Current assignee: SPX Corp
Priority date: 1930-12-08
Filing date: 1930-12-08
Publication date: 1937-10-26
Anticipated expiration: 1954-10-26

Description

Oct. 26, 1937. w. w. WENHOLZ CENTRALIZED TRAFFIC CONTROLLING SYSTEM Filed Dec. 8, 1930 3 Sheets-Sheet l QIH INVEN'TQR BY 1 flu? Oct. 26, 1937. w. w. WENHOLZ I 2,096,832

CENTRALIZED TRAFFIC CONTROLLING SYSTEM Filed Dec. 8, 1930 s Sheets-Sheet 2 WM m MATTORNEY Oct. 26, 1937.

w. w. WEJ NHOLZ CENTRALIZED TRAFFIC CONTROLLING SYSTEM-- Filed Dec. 8, 1930 3 Sheets-Sheet 3 I'll-ll II.

sill-ll Illlll lNVENT w. Fad BY [(6 ATTORNEY hw Ill NJ 0 Patented Oct. 26, 1937 UNITED STATES PATENT OFFHCE CENTRALIZED TRAFFIC CONTROLLING SYSTEM Walter W. Wenholz, Rochester, N. Y., assignor to General Railway Signal Company, Rochester, N.

Application December 8, 1930, Serial No. 500,802

46 Claims.- (01. 246-3) 0 one time, and where following trains are protected by signal indications of clear, caution and stop the same as in double track signalling where trains can move in one direction only. In. other words, an absolute-permissiveblock or A. P. B. system blocks all opposing trains and pcrmits the movement of following trains with the usual train spacing. In absolute-permissiveblock signalling systems of the superimposed manual control type, the starting signals as Well as the entering signals located at each end of each single track section have superimposed thereon manual control, so that these signals may be heldat stop through. suitable control mechanism controlled from a central office. A system of this type has been shown in the prior application of S. N. Wight, Ser. No. 48,553 filed August 6, 1925. Absolute-permissive-block signalling systems usually include two tumbledown circuits, one for each direction of trafiic through the medium of which the home-anddistant relay for each signal of a single track section is controlled by the home-and-distant relay of the signal next in advance, these tumbledown circuits using a common return wire, so that at least three line wires are necessary, the common wire of which can of course not include any track relay contacts. nal engineers are unwilling to rely on a circuit for railway signalling purposes extending any appreciable distance along the railway track without breaking such circuit for each wire at each track relay, so that as a matter of fact the signal system of the prior application of Wight above referred to would require four line wires to carry out this checking theory.

In view of the above and other important considerations, it is proposed in accordance with the present invention to employ only two line wires extending from each signal location to the next signal location in a single track section, to break both of these line wires at each track relay, and to use the same two line wires in each of the two tumble-down circuits, each section of these tumble-down circuits having a source of current atone end and a relay at the other end for one direction of traflic movement, and having a relay at said one end and a source of current at said other end for movement oif trafiic in the opposite direction, suitable manu ally superimposed control being employed to Certain .sig-

change the direction of traffic and the direction inwhich these tumble-down circuits have over lapped control.

Other objects, purposes and characteristic fea tures will be obvious from the accompanying drawings and will in part be pointed out in the specification hereinafter.

In describing the invention in detail, reference will be made to the accompanying drawings Figs. 1A and 1B which if laid end to end illustrate only one single track section and the adjacent ends of two passing sidings of a railway signalling system embodying the present invention, and to Fig. 2 which shows somewhat more in detail'the wiring for signals 4 and 6, wired as shown for signal 4 in Fig; 1A and with the home-distant relays shown conventionally as relays of the polar neutral-retained type.

- Although only one single track section 0 and a portion of two passing sidings PS and 0 PS have been illustrated in the drawings, it is to be understood that a large number of single track sections are connected by passing sidings in practicing the invention, and that the left hand or west end of the passing siding PS is 1 controlled by apparatus such as shown at the west end of passing siding PS and that similarly the east'end of passing siding PS is equipped with apparatus such as shown at the east end of the passing siding PS passing siding PS is provided with a track switch S which track switch may be either manually operated or may be operated by a switch machine all in a manner as described. in the prior applicationabove referred to and for convenience no specific means for operating the switch S has been illustrated, as is also true of the track switch S located at the west end of the passing siding PS The track switch S has associated therewith a main entering signal l, a take-siding entering signal i a main starting signal 2 and a dwarf starting signal 2 the entering signals of which govern the movement of trains into the main track and side track, respectively, whereas the starting signals govern the movement of trains oii of the main track and the side track, respectively, into the single track section 0.

The east end of the Similarly, the track switch S has associated therewith starting signals l and i and entering and are preferably three indication signals and are controlled by homeand-distant relays through suitable means illustrated by dotted lines, so that each signal displays a clear or green signal when. the ho-me-and-distant relay assumes its right hand energized position, indicates caution when the lhome-and-distant relay'assumesj its left hand energized position and indicates stop if the home-and-distant relay is deenergized.

7 These various home-anddistant relays have been designated HD with a prefix corresponding to the signal which it controls. In this connection it may be pointed out that entering and starting signals are not directly controlled by their associated home-and-distant relays but are controlled through repeater relays designated G with a prefix corresponding to the number of the signal, these signal relays IG, 2G, 1G, and 86 having superimposed detector track circuits and manual control, the manual control of these starting and entering signals being carried out through the medium of the east relay ER the east relay ER the west relay WR and the west relay WR}, controlled from a central dispatchers oiiice D0, in which the passing sidings are re-' produced in miniature by passing siding PS and PS ,'as indicated. The single track section 0 as well as the main track of the passing siding is divided by insulating joints l0 into track circuit sections, of which the single tracksection 0 con tains track circuits including track'batteries ll, I2, [3, I4, I5, I6, [1, and it for controlling

track relays

2T, 3T, 4T, 5T, 5T ST, ST, and IT,

whereas the track switch S has associated there with a detector track circuit including a track relay 2DT and a battery 26, and the trackswitch S has'associated therewith a detector track circuit containing a track'relay 'lDT'rand 'a track battery it. v V j The main track of the passing siding PS is provided with a track relay IT and "a battery 2|, whereas the main track of the passing siding PS is provided with a track circuitcontaining a track relay 8T and a track battery 'H'. tion is directed to'the. fact that the signals 3 and 4 are opposite signals and govern trafllc-in opposite directions and a-re'located at the same point whereas the signals'5 and Bare staggered signals in; that they are not located at the same point and also govern trafiic in opposite directions. These staggered signals5 and 6 have.

*fic is set up at intermediate signals is an in- V been illustrated for the purpose of showing how' the novel circuit arrangement may be applied to a staggered signaltype A. P. B. system Without the use of more than two wires along the .trackeven at a staggered signal location. v

Attention is directed to the fact that signals 4 and 6 are illuminated, signifying that they are indicating either caution or clear, whereas the signals 3 and 5 are not illuminated conventionally indicating that they are in-the stop a condition. .This fact that onedirectionof trafherent condition in the system, and is due to the characteristic that the tumble-down circuit which was last established remains in its established condition even thoughthe starting and entering signals at both ends of the single track section are thereafter put tostop, as will be readily understood after the operation of the system has been considered.

Although the control relays ER ER WR and WR may be controlled as illustrated in the drawings or as illustrated in the prior applicawire 21.

Atten:

tion of S. Wight, Ser. No; 48,553 above re ferred to, these signals are preferably controlled by a suitable selector type system, such forin- 7 stance as illustrated in the prior application of Preston and Hitchcock, Ser. No. 455,304, filed May 24, 1930. These relays ER EH WR and WE are preferably two position relays of the.

polar magnetic stick type, as conventionally illustrated by the solid square, which relays may be operated to' one position by current of one polarity and may be operated to the other position by current of the reverse polarity and will remain in the last operated position even though their energizing circuits are broken. .The relay" vE1 5 is controlled by the lever L located at the central oflice DO through the mediumof wire.

fix corresponding to that, of the signal. These directional'stick relays are controlled in. the usual way as more specifically pointed out in the prior application of S. N. Wight, Ser. No. 120,423 dated July 3, 1926, andgenerally'speaking each include a pickup circuit including a front contact of its associated home-and-distant relay and a back contact of the track relay next in advance of the signal associated therewith, and having a stick circuit including a'back' contact of said as-' sociated, ho'me-and-distant relay '(see circuits of stick relays 2S andlS in'the drawings).

' It is considered expedient to'first trace all of thecircuits which are shown closed in the drawings .andithen consider the operation of the systern As shown in thedrawings the back-andforth relay BF is shown energized through a pick-upcircuits-beginning at the terminal of a suitable battery, contact '32 of the

relay WR wires

33 and 34, winding of the relay BF to the terminal'of this same battery; and a stick circuit'beginning at the terminal (+)..of said battery, the back contact 35fof the relay 'IHD, wires 36, stick contact 31 of the relay BF wires 38 and 34, winding of the relay BF to the terminal of said battery. 'Ihe back-and forth relay BF, on the other hand, is only energized through its pick-up circuit, which may be traced as follows:beginning at the terminal normally closed contact 40 of-the relay EH wires and 42, winding of the relay BF to the other terminal of the same battery. The

relays BF and BF. have been called back-and- 'forth relays, because a back-and-forth movement of the relay ER is necessary to obtain a,

result.

'The home relay 6BR is shown energized through the following circuit-beginning at the ,terminal of a suitable battery, resistance unit R preferably comprising a resistance of ohms, back contact 44 of the'relay 36', wire 45, front contact 46 of the detector track relay IDT, wire 41, back Contact 58 of the. direction relay DR wire 49, front contact 58 of the track relayJT, wire 5|, front contact 52 of thetrack relay'fiT, wire 53, back contact 54 of the directional stick relay 58, wire 55, back contact 56 of y the home-and-d istant relay 5HD, wire 51, windand-distant relay has associated therewith a directional stick relay designated S with'a 'pre-.

ing of the home relay GHR, wire 58, back contact 59 of the relay EHD, wire 50, back contact 6| of the relay 58, wire 62, front contact 63 of the track relay 6T, wire 94, front contact 65 of the relay lT, wire 69, front contact 91 of the track relay EDT, wire 98, back contact 69 of the relay DB wires 12 and 13, back contact 14 of the relay 8G to the other terminal of said battery.

With the home relay .iI-IR energized the following energizing circuit for the home-and-distant relay 61-203 is closed:-beginning at the terminal of a suitable battery, wire 99, polar contact 19 of the relay GHR, wire 80, front contact tI of the relay GHR', wire 82, front contact 83 of the relay 5T wire 84, front contact 85 of the relay 6T wire 89, back contact 81 of the relay 5HR. wire 88, winding of the relay SHD, wire 89, back contact 90 of the relay EHR, wire 9!, front contact 92 of the relay 6T wire 93, front contact 94 of the relay 5T wire 95, front contact 95 of the relay SHR, wire 91, polar contact 98 of the relay BHR, wires 18 and 16, winding of the approach lighting relay AL back to the terminal of the same battery.

With the relay SHD now energized the e'nergiz ing circuit for the relay II-ID may betraced as follows:-beginning at the terminal of a suitable battery, winding of the approach lighting relay AL wires I02 and I93, front contact I04 of the relay fiHD, wire H15, back contact I93 of the relay 63, wire Ifil, front contact I98 of the track relay 5T, wire Hi9, front contact $9 of the track relay 4T, wire ll, back contact H2 of the relay 33, wire H3, back contact I Hi of the relay 31-113, wire H5, winding of the relay AHD, wire Ilfi, back contact ill of the relay SHD, wire H8, back contact H9 of the relay 38, wire 5%, front contact I2I of the track relay 4T, wire I22, front contact I23 of the relay'ET, wire Ht, back contact I25 of the relay 68, wire I29, front contact I2! of the relay EHD to the other terminal of the same battery.

With the relay AHD energized the following energizing circuit for the home relay 21-11) is closed:-beginning at the terminal of a suitable battery, winding of the approach relay AL wires 30, 53 and I32. front contact i553 of the relay iTrID, wire 634, back contact I35 of the relay &8, wire 136, front contact I3! of the relay 3T, wire 539, front contact I39 of the relay 2T, wire I49, front contact lei of the direci tion relay DB wire I42, winding of the relay ZHD. wire M3, front contact I44 of the relay DB wire 5'95, front contact MS of the track relay 2T, wire I41, front contact I98 of the relay 3T, wire I49, back contact I50 of the relay 05, wire IEI, front contact I52 of the relay ll-1D, to the other terminal of the same battery.

With the home relay 211D energized the direction relay DB is energized through the follow-- ing circuit:beginning at the terminal of a suitable battery, front contact I59 of the relay ZHD, wires H55, I55, I51, and I58, winding of the relay DB to the other terminal ofthe same battery. In this connection it should be'noted that the relay DB is energized through a front contact of the relay 21-113, and the relay ZHD is energized through front contact of the relay DB Obviously, the relay DB was energized through another of its various energizing circuits at the time the relay ZHD was picked up. These interrelated circuits wlll be more particularly considered in connection with the operation of the system. Attention is directedto the fact that although the relay 22113 is energized, signifying that traffic conditions in advance of signal 2 are either clear or caution, the signal 2 controlled by the relay 2G is held at stop because the circuit for the relay 2G is open at the polar contact E69 of the control relay EH i Referring to the various circuits just traced, and particularly the circuits for the relays ZED, 4HD, and BHD, it will be noted that each of these home-and-distant relays are controlled by hom'e-and-distant relays having a higher prefix, except that the relay SI-ID is controlled by the relay 8G which latter relay is controlled relay 8HD. Also, it will be noted that the circuit for eachof these home-and-distant relays includes all of the track relay contacts between it and the next signal in advance, and that these track relay contacts are included in both wires of the circuit, this in order to give an additional assurance against crosses and accidental sticking up of some of these contacts. Attention is further directed to the fact that the relay 61-113 is not directly controlled. by the relay 8G as above inferred, but is controlled by this relay 86 through the medium of the home relay til-EL, this because the relay GHD is located at a staggered signal location.

Each of these various home-and-distant relays has been illustrated as a polar-neutral relay hav-, ing both polar and neutral contacts, but the invention is not limited to this particular construc-' tion, for in case of alternating current systems a polar relay of the three-position induction type would preferably be used. In a direct current system, such as illustrated, these various home" and-distant relays as well as the home relays BER, and BHR are preferably relays that will not open their neutral contacts upon reversal of current applied to its windings, such for instance as shown in the application of Larson, Ser. No. 253,880 filed FebruarylB, 1928, now Patent No.

1,852,210 granted April 5, 1932. These relays- HD andHR, with various prefixes may also comprise a polar relay connectedv in series with a neutral relay which'will not open its contacts upon reversal of current in the circuit, the neutral relay being'constructed as shown in the application of O. S. Field, Ser. No. 428,090 filed February 13, 1930, now Patent 1,852,406, granted April 5, 1932, and. on the other hand the neutral contacts for these various hcmeea-nd-distant relays and home relays may be shifted to a slow acting repeater relay which repeats the condition of energization of such home-and-distant or home relay, so that the circuit for the next homeand-distant relay in the rear will not actually be broken upon pole changing of the corresponding circuit in advance.

Studying these various home-and-distant relay circuits it will be noted that in each of these circuits wires are provided with a source of current at the east end and a relay at the west end, but that-upon energization of the relays 3l-ID,

5I-ID and SHR and upon deenergization of the relays 4HD, GED, and SEE each of these circuits will have a relay on the east end thereof and a source of current on the west end thereof, these various features of interlocking will be i more clearly apparent upon consideration of the operation of the system.

Although no specific circuits have been illus trated for controlling the various signals by their respective home relays or signal relays, these various signals may be controlled in any well known way, such for instance. as illustrated in the prior application of S. N. Wight, Ser. No. 48,553

conditionof occupancy, of the various detector.

' track circuits, the position of the track switches,

and the like, it is to be understood that suitable means such as indicated in any of the prior applications above referred to may be employed.

Operation As heretofore mentioned, and as manifested by the illumination of signals 4 and 6, the last direction of train movement was from left to right, that is from'west to east, and for this reason we 'will assume that there is a train on the main track of the passing siding PS and that the operator in the central office DO'wishes to allow this train to pass through'the single track section 0 and into the main track of the passing siding PS It will of course be necessary for the operator to clear the signal 2 before the train under consideration can proceed intothe single track section 0'. The operator Will -therefore move his lever L to its right hand position, and

in so doing will apply current of positive polarity 'to the line wire 25 thereby'operating the control relay ER to the right, it'being noted that the contact 26 of the lever L will not be connected to energy when the lever L assumes "its right hand position; a a

Movement of the control relay 'ER? to the right deenergizes the back-and-forth relay BF this 7 because the stick circuit for this relay BF is broken at the back contact I54 of the may ZHD.

The relay BF is a slow acting relay, and for this reason current may momentarily :flow'through the contact 40 of the relay ER assuming its right hand position through the wire I10, front contact I1I of the relay BF wires I12, 'I56, I51, and I58 to the direction'relay DRE. This I momentary'completion of the circuitjusttraced is, however, of no importance at this 'time,-because the relay DB is now energized through the front contact of the home relay 2HD. Movement of the contact I60 of the relay ER to its right hand position, will however close the. following circuit for the signal relay 2G:beginning at the terminal of a suitable split battery, polar contact I14 of the relay ZHD, wire I15, neutral 'contact I16, wire'I11, switch box contact I18 closed only when the track switch S is in its main track position, wire I19, front contact I80,

of thedetector track relay 2DT, wire I8I, winding of the relay 2G, wire I82, contact I60 of the V relay ER assuming its right hand position to the middle point C of this split battery. The completionof the circuit just traced energized the relay 2G and displays a green proceed indication by the signal 2. In this connection it should be noted that ifthe relay ZHD is energized to the reverse position the polar relay 2G.will'be energized to its reverse position and will cause the signal 2 to display a'yellow caution signal. j

The east bound train under consideration may now pass oif of the main track of the passing sid -1'ng PS in response to the clear signal 2 and into the single track section O. -As'-soonas this train treads upon the detector track circuit associated with the switch S the track relay ZDYI:

will be deenergized, thereby opening its contact I and actuating the signal 2 to its stop position or condition. Deenergization of the relay 2G will of course pole changecthe energizing circuit for the next home-and-distant relay in the rear, thereby causing the display of a caution signal at the entering signal at the west end of the passing siding PS in accordance with the usual practice, it being understood that the entering signals I and 8at opposite ends of the passingsiding-are interlocked so that only one of the entering signals can indicate proceed at one time, all as clearly disclosed inthe prior application Ser. No.

120,423 above referred to.

The dropping of the detector track relay 2DT not only effects deenergization of the relay 2G,

but by theclosure of its contact I84 closes the following pick-up circuit for the relay 2S:beginning at the terminal of a suitable battery, front contact I85 of the relay ZHD, wire -I86, back contact I84 of the relay ZDT, wires I81 and I 88, winding of the relay 2S, to the other terminal of said battery. As the train in question now passes the. insulating joint I0 adjacent the signal I,. it will shunt the track relay 2T, thereby effecting deenergization of the relay 2HD and in so doing will close the following stick cir-. cuit for the relay 2S:beginning atthe terminal back contact I85 of the relay 2HD, wire I89, front contact I of the relay 2S, wires I 9| and I 88, winding of the relay 2S, to the otherterminal v Although dropping of the relay 2HD'bythe' opening of its contact I54 will break the circuit heretofore traced for the direction relay DR this direction relay DR, will remain energized through the medium of the following auxiliary circuitz-e. beginning at the terminal front contact I93 of the. relay 2S,-wire I94, front contact I95 of the relay DR wires I96, I51 and I58, winding of the relay DR, to the other terminal ofrsaid battery. 7

As the train under consideration proceeds in an easterly direction, it will drop the track relay 3T and thereafter pick up thetrack relay 2T, and upon its passage of the signal 4 which 4 displays .a clear or green signal it will drop the track relay 4T and in so doing pick up the stick relay 4S, which stick relay 4S is controlledin the same way as the relay 2S. Picking up of the relay 48 will reverse the polarity of current applied to the relay 2HD, and as soon as the rear end of the train passes off of the track circuit containing the track relay 8T the relay 2HD will be energized to its reverse position and will cause the signal 2 to display a caution indication. The

signal 6 is still displaying a caution signal, bea cause the signal relay 86 under the assumed condition remains deenergized,

The operator in the meantime will have operated his lever L to the right hand position and .will thereby apply current of positive polarity to suitable splitbattery, polar contact I98 of the relay 8HiD assuming its right hand position, wire I89, front contact 200 of the relay 8HD, wire 20I,

winding of the relay BG, wire 202, front contact 203 of thetrack relay 1DT, wire 204, switch box contact 205 closed only if the switchgS", is in the main track position. wire 206. contact 201 of the relay ER to the mid-point C of the split battery. Energization of the relay 8G will not only cause the signal 8 to display a clear or green signal, but will also pole change the current applied to the circuit for the relay BHR, without opening the neutral contacts 8! and 96 of this relay for reasons heretofore given, so that this relay GHR, will have its polar contacts move from its left hand to its right position. With the relay ESHR assuming its right hand energized position instead of its left hand energized position the polarity of current applied to the relay BED is reversed, so that this relay BHD assumes its right hand instead of its left hand position and causes the signal 5 to assume a clear instead of a caution position. The train under consideration is 'now assumed to be moving in an eastwardly direction between the signals 4 and 5. As this train passes the signal 6 it will cause the directional stick relay 68 to be picked up, thereby reversing the polarity of current applied to the relay 4HD, and thereby causing the signal 4 to display a caution signal as soon as the rear end of the train passes the signal 6. Also, as the rear end of the train passes the signal 6 the stick relay 4S will again be deenergized, this because the relay 4H1) picks up, and this deenergization of the relay 4S and energization of the relay ll-ID causes current of positive polarity to be applied to the relay ZED,

thereby causing a clear or green indication to be displayed by the signal 2 instead of a caution indication. I

Movement of the train under consideration in an eastwardly direction between the signals 5 and 5 will of course cause the relaytHD to be de energized because the track relay GT and 5T will be deenergized during this movement of said train, and similarly as the train moves between the signal 5 and the signal 8 the home relay BHR, will remain deenergized, and it will thereby cause the relay iii-ID which repeats the relay BHR to be deenergized, and as soon as the train passes the signal 8 the detector track relay 1D'I is deenergized thereby opening the circuit for the signal relay 8G at the contact 293, and thereby causing the signal 8 to display a stop signal. It is of course understood that the signal 8 is thereafter controlled in accordance with the condition of energization of the home relay 8HD and as soon as the'train in question passes beyond the detector track circuit 1DT the relay 8G is controlled in accordance with the position of this relay BHD. The home-and-distant relay BHD is of course controlled in accordance with traffic conditionsin advance as indicated in the prior application No. 120,423 above referred to.

Let us now assume that there is a west bound train on the main track of the passing siding PS and that the operator Wishes to change the direction of tram-c movement in the single track section 0. Under ordinary working conditions the operator will first restore his lever L to normal and thereby return the relay ER to normal. Let us however assume that for some reason or other, such as a broken line wire, the operator is unable to change the position of the relay ER which now assumes its right hand position and causes the starting signal 2 to display a proceed indication. The operator now moves his lever L to its left hand position signifying permissible west bound entrance of a train into the single track section 0. This movement of the lever L when it reaches its intermediate position, effects momentary negative energization of the wire 30 thereby causing the relay EH to be moved to its left hand position if it has not already assumed such position. When the lever L reaches its extreme left hand position current of negative po larity is applied to the control relay WR thereby operating this relay WR to its left hand dotted position. The relay 1HD is of course still deenergized because the direction relay DB is still deenergized, and with the relay lHD deenergized the relay IBF is energized through its stick circuitheretofore traced. Movement of the relay- WR to its left hand position therefore completes the following pick-up circuit for the relay DB beginning at the terminal of a suitable battery, contact 32 of the relay WR. t0 the left, wire 218, front contact-2H of the relay BF wires 212, 213, M4, and 2I5, winding of the relay DB to the other terminal of said battery.

Picking up of the direction relay DB will of course eil'ect deenergization of the relay BHR, because the relay 1HD is now connected to the east end of the line wires connecting signal locations 5 and 8. Deenergization of the relay GHR will effect deenergization of the relay 6HD, deenergization of the relay GI-ID will effect the deenergization of the relay 4HD, and deenergization of the relay 4HD will effect the deenergization of the relay. El-ID. In other words, a tumble down have been deenergized as soon as the relay ZHD' picked up after it had been deenergized by passage of the east bound train, thisbecause its stick circuit including its stick contact 2I1, wires 2i$ and 2I9 and back contact I54 of the relay ZHD was broken when this relay 2HD picked up. Furthermore, the dropping of the relay 2HD, by the tumble down function just explained, opens the front contact I54 of the relay 231D and effects dropping of the direction relay DB it being understood that the relays BF and 28 are now deenergized. With the direction relay DR now deenergized, the following energizing circuit for the home relay 3HD is completed:'beginning at the terminal, resistance unit R preferably of 100 ohms resistance, back contact 22I of the relay I G, wire 222, front contact 223 of the track relay 2DT, wire 224, back contact I4I of the relay DB elements I40, I39, I38, I31, I36, I35, I34, I33, and 226, winding of the relay 3HD, elements 221, I52, I5I, I59, I49, I48, I41, I46, I45, I44, 228, .229, 239. and 23I and back to the terminal of said battery. The completion of the circuit just traced will cause the relay 3HD to assume its left hand energized position, thereby causing the signal 3 to display a caution indication.

Picking up of the relay 3HD will cause the following circuit for the relay 5HR. to be completed:beginning at the terminal of a suitable battery, ,winding of the approaching lighting relay AL35,' elements, I35, 233, II -l, IE9, i I2, III, I10, I59, I08, I91, I09, I95, I94, and 234, winding of the relay 5HR, elements 235, I21, I26, I25, I24, I23, I22, IZI, I29, H9, and H8, contact H1 in its energized position, to the other terminal of said battery.

The completion of the circuit just traced .will" energize the relay 5HR to its right hand position, thereby completing an energizing circuit for the relay 5HlI) which may be traced as follows:beginning. at the terminal of a suitable battery,

. and 249, winding of the relay elements 24! 7 81., 82, 83., 84,85, 86, 81, and 242, contact 243 of the relayBI-IR assuming its right hand position to the other terminal of said battery. The completion of the circuit just traced will energize the relay HD to its right hand position, thereby 7 causing'the signal 5 to display a clear proceed position.

With the relay 5HD energized the following energizing circuit for the relay 'IHD is closed:

beginning at the terminal of a suitable battelfy, Winding of the approach lighting relay AL elements 16;", 245, 246, 56, 55, 54; 53, 52, 5|, t 59, 49, 48, 24 i, winding of the relay IHD, ele- 'ments 248, 69, 68, 6 66, 65, 64, 63, 62, Hand fill, contact 59 of, the relay 5HD in its attracted position, to the other terminal of said battery. t 7 V With the relay IHD now energized toits right hand position and the control relay WR assuming'its left hand position the following energizing circuit for the signal relay 1G. is completed: beginning at the terminal of a suitable split.

' battery, contact 250' of the relay 'IHD, wire 25!,

front contact 252 of the. relay II-ID, wire 253, front contact 254 of the track relay IDT, wire 55, switch box contact 256: closed only, when the t-ch S is in its main track position,'wire 251,

winding of the relay 1G, wire 258,.contact 259 to display a clear or green proceed indication,

thereby allowing the west bound train occupying the main track of the passing siding PS to proceed into the single track section 0. The train under consideration will of course encounter a caution signal when it reaches the signal 3-, this becausa'asassumed, the operator was unable to change the position of either ofthe relays ER or WE at the west end of. the single track section 0. The train can of course proceed atcaution until it reaches the signal I at which time the train crew can get in communication with the operator through the. medium of'atelephone, preferably located. at the end of each passing siding.

I-t its-thus San that irrespective of the condition of the control relays, such as, relays ER. and WR at one end of a single track section the operator may through the medium of the control relays at the other end ofthe single track section change the direction of train movement in such'sing le track section. This .is accomplished by reason of the back-and-forth stick relaysBF and BF, these relays enabling the direction relays DR; or DR. to be picked up only in response to a backand-forth movement of the contacts of the relays'lLR and WR respectively. These backand-forth relays canbe picked up only with the associated control relay ER or WR in one position and allow the directionrelay'DR or DR. to be picked up only through a front contact of r the back-and-forth relay and with the control relay ER or WR assuming the opposite position. Similarly, the direction relay DR, if once picked up, as for instance in the manner just indicated,

, thereafter can'be held up only through either a holding circuit or a stick circuit the holding cir-. cuit of which includes a front contact of the associated. home relay, THD which can only be up with this direction relay DR up, and the other or stick circuit of which includes a front contact of the associated directional stick relay 'lSyfrom which it is apparent that with no train in the single track section, the directional stick relay TS must assume its deenergized position, so that the directionrelay DB may be deenergized from the oppositeendof the single track section, by reason of the fact that the home-and-distant relay II-ID, associated with such direction relay, is in a tumble-down circuit energized from the opposite end of thesingle track section. In other words, to change the direction of traflic movement, the home-and-distant and home relays are caused to tumble down in one direction and in sojdoingleffect deenergization of the direction relay at the remote end of the single track section, and with this direction relay once deenergized the home relays for governing the opposite direction of traflic will tumble up, so to speak.

' It has already been explained how the operator may set up a direction of traffic to allow a train to move into. one end of a single track Section even though he hasrno control over thecontrol relays located at, the opposite end of the single track section; Let us now see how the train crew may itselfset up its ,own direction of traffic in the event'that the entire selector system or other control for th various control relays ER and WR is out of order, and that the operator has absolutely nocontrol over the system. In this case,

' the train crew when it is*ready to enter a single track sectionfiwill get into communication with theoperator at the central ofiioe to receive orders,

as over the telephone system, oreven without any order from the operator in case the telephone system is out of order, a member ofgthe traincrew will depress the push button PB 'if they are located at the West end of the single track section O-or the push button PI? if they are located at the east end of this single track section, and in so doing will effect energization of the'associated direction'relay DR or DB and thereby will cause the direction of trafiic to be changed in exactly the same manner as heretofore described in connection with the west bound train movement through the single track section 0, except that the direction relay DB is now picked up by the push button BB where in. thecase. heretofore: considered in detail this relay DR. was picked up by the operation of the control relay WR; to its left hand position. Should, however, the relay WR 'be assuming the right hand position, under which condition the.

relay 1G cannot be picked up and the signal I cannot be cleared the call-on. signal CO would be cleared through the front contact 268 of the. relay 'IHD and the back contact 261 of the push button P3 Referring to Fig. 1A be noted that the relay2HD is energized over the line Wires [36, and 5449 by a source'of current located at the signal 4. It willalso be noted that if relay DR were to be deenergized, that by such deenergization of relay DB the line wires--l36-l40 and l45-l49 would be connected to a source of current located at the signal '2 through the medium of back contact MI and 144 of relay .feeding'track relay 2' I or 3T, such momentary deenergization could cause deenergization of the relay DB and as soonas .the crowbar is removed of the drawings, it 'win" there would be a source of energy at each end of the line wires [36-540 and 145-549, and the voltages of these sources might be cumulative. Such simultaneous application of energy on the opposite ends of the line wires MiG-I40 and I45- l l9 is however not detrimental to these sources of current, by reason of the inclusion of the resistance R in the circuit. Furthermore, such simultaneous application of two sources of current on the same line circuit should be a very rare and unusual occurrence. What has been said in regard to the purpose of the resistance R shown in Fig. 1A is also true of the resistance R shown in Fig. 1B.

The applicant has thus provided an A. P. B. system with supervisory control from a'central office, which has all of the operating characteristics of commercially recognized practical absolute-permissive-block systems, in which he has used less line wires and in which his circuits are protected by more relay contacts, to assure against various false indications due to crosses or sticking relay contacts, and in which each home-anddistant relay has its energizing circuit checked through the back contact of the home-and-distant relay for governing opposing train movements, for instance, home relay 3H1) can only be energized through back contacts of home relay 4I-ID, and home relay tHD can only be energized through back contacts of relay SI-ID. Furthermore, the system is so organized that upon failure of a portion of or the failure of the, entire manual supervisory control system, a reversal of direction of trafilc may be set up by the train crew from that end of the single track section from which the train under the control of such train crew must enter. Also, the momentary false closure of a particular home-and-distant relay circuit, as for instance by a short train, such as a gasoline propelled car, moving, as for instance,

from the track circuit of relay 21'' into the track circuit of relay 3T, thereby momentarily closing the energizing circuit for the home relay in the rear, cannot set up any false indication permanently, as is apt to be the casein absolutepermissive-block systems of earlier construction, this by reason of the fact that the various homeand-distant relays are so interlocked that only one direction of traffic can be set up at one time, and the system is so organized that the train itself cannot set up such direction of traffic, the direction of traffic being determined entirely by the condition of energization of the direction relays DR and DR located at opposite ends of a single track section. It is of course understood that the intermediate signals 3 and 4 or 5 and 6, together with their associated circuits may be omitted, if desired.

It is, of course, understood that the track switches S and S are preferably controlled from the central oflice DO, as through the medium of a switch machine, and that the. starting dwarf signals 2 and i and the entering signals I and 8 will be cleared in accordance with the direction of traflic to be set up providing of course that the track switches with which they are associated assume the take-siding position, all as shown in the prior applications above referred to.

Fig. 2

In Fig. 2 has been illustrated a little more in detail the wiring for signals 4 and 6 of two intermediate signal locations, where both of these signal locations have their signals located. opposite as distinguished from having the signals staggered. The home-distant relays tHD and BI-ID are wired the same as is the relay 61-11) for Fig. 1A, that is, energy is applied to the line circuits in identically the same manner as the relay 4H1) of Fig. 1A applies energy to the line circuit for the next relay in the rear, and the relays ill-ID and fiI-ID are connected to the line circuit in exactly the same manner as relay AHD of Fig. 1A is connected to the line circuit. .The signals 3, 4, 5, and 6 have been illustrated as three-aspect color light signals, none of these signal aspects of green G, yellow Y or red R being lighted, however, unless the approach lighting relay AL associated with that signal is deenergized. The reference characters employed in Fig. 2 are the same as in Fig. 1A, except that distinctive exponents 4 and 6 have been added. The windings b of the.

HD relays receive their energy conductively from i the windings a, and these windings a are inductively connected to the main windings of these relays. The operation of the system to control signals 4 and 6 of Fig. 2 is exactly the same as the operation of signal 4 of Fig. 1A, and therefore need not be repeated.

Having described one rather specific embodiment of the present invention it is desired to be understood, that the particular embodiment illustrated has been illustrated for the purpose of disclosing the nature of the invention, its operating characteristics and its underlying principles, and that the particular embodiment selected has not been selected for the purpose of showing the scope of the invention nor the exact construction preferably employed in practicing the same, and that various changes, modifications and additions may be made to adapt the invention to the particular type of railway system to which it is to be applied, all without departing from the spirit or scope ofthe invention or the idea of means underlying the same, except as demanded by the scope of the following claims.

' What I claim as new is:-

1. In an absolute-permissive-blook signaling system for railroads, a single track section, signals at each endof said section for governing the entrance and exit of trains into and out of said section, signals at an intermediate point for governing the movement of trains in both directions through said section, a circuit leading from one end of said section to said intermediate point for at times controlling a signal at said one end and at other times controlling a signal at said intermediate point, another circuit leading from the other end of said section to said intermediate point for at times controlling a signal at said intermediate point and at other times controlling a signal at said other end, and means for at times controlling said one circuit by said another circuit and for at other times controlling said another circuit by said one circuit.

2. In an absolute-permissive-block signal system, the combination with a single track section,

signals for governing the movement of trains through said section, means for controlling said signals including two circuits arranged end to end and together extending the length of said section, means for at one time controlling one of said circuits by the other circuit and at other times controlling said other circuit by said one circuit, and two stick relays for determining which of said two circuits shall control the other of said two circuits.

3. In an absolutepermissive-block block signal system, the combination with a single track section, signals for governing the movement of trains signals including two circuits arranged end to end and together extending the length of said section, means for at one time controlling one of' said circuits by the other circuit and at other times controlling said other circuit by saidione circuit, two stick relays for determining WhiCh'Of said two circuits shall control the other of said two circuits, and a control relay controlled from a distant point for each of said stick relays f controlling the same. 7 4. In an absolute-pernfissiVe-block signal system, the combination with a single track section, signals for governing the movement of trains through said section, means for controlling said signals including two circuits arranged end to end and together extending the length of said section, means for: at onetime controlling one of said circuits by the othertcircuit'and at other times controlling said'other circuit by said one circuit,

'two stick relays for determining which of said 7 'two circuits shall control the other of said two circuitsa control relay controlled from a. distant point for each of said stick relaysfor controlling the same, and a pick-up circuit for each of said stick relays which when such stick relay is deenergized can be closed onlyupon a change in the position of its associated control relay;

5. an absolute-permissive-block signal system, the combination with asingle track section, signals for governing the movement ofiQtrains through said section, means for controlling said signalsincluding' two circuits arranged end to end and together extending the length of said section, means for at one time controlling one of said circuits by the other circuit and at other times controlling said other circuit by said one circuit, two stick relays for determining which of said two circuits shall control the other of said two circuits, a control relay controlled from a distant point for each of said stick relays for controlling the same, and a pick-up circuit for each of said stick relays which can be closed only position of its associated control relay; I V i d 5. man absolute-permissive-blocksignal systom, the combination with a single track section,

signals for governing the movement of trains through said section, means for controlling said signals including two circuits arranged end to end and together extending the length oi said section, means for at one time controlling '-one of said circuits by the other circuit and at other times controlling said other circuit-by said one circuit, two stick relays for determining which of said two circuits shall control the other of said two circuits, an auxiliary relay for each of said stick relays, a control relay for each of said stick relays, a circuitior each auxiliary relay closed only when the associated control relay assumes one position, and a pick-up circuit for each stick relay closed only when the associated control relay assumes anotherpo'sition and then only if the associated auxiliaryrelay assumes its ener- V gized position.

'7. In an absolute-permissive block signal system, the combination with a single track section, signals for governing the movement of trains through said section, means for controlling said signals including two circuits arranged end to end and together extending the length of said section, means for at one time controlling one. of

' said circuits by the other circuit and at other times controlling said other circuit by said one circuit, two stick relaysfor determining which of said two circuits shall control the other of said two circuits, an auxiliary relay for each of said stick relays, a control relay for each of said stick relays, a pick-up circuit for each auxiliary relay closed'only when the associated control relay assumes one position, and a pick-up circuit for 'each stick relay closed only when the associated control relay assumes another position and then only if the associated auxiliary relay assumes its energized position.

two circuits, an auxiliary relay for each of said 7 stick relays, a controlirelay for each of said stick relays, a pick-up circuit for each auxiliary relay closed only when the'associated control relay as sumes one position, a, stick circuit for each auxiliary relay closed if the associated stick relay assumes its deenergized position, and a pick-up circuit for each stick relay closed only when the ssociated control relay assumes another position and then only if'the associated auxiliary relay assumes itsenergized position.

9. In an absolute permissive-block signaling systemior railroads, a single track'se'ctiomsigs nals at each end of said section for governing the entrance andexit of trains into and out of said section, signals at an intermediate point for governing the movement of trains in both directions through said section, a. circuit leading from one i 7 end of 'said'section to said intermediate point for ,at times controlling a signal at said one end and at other times controlling a signal at said intermediate point,another circuit leading from the otherend of's'aid section to said intermediate a point for at times controlling a signal at said intermediate point and at other times controlling a signal at said other end, two relays located at said intermediate point one at times included in one of said circuits and the other at times included in the other of said circuits, interlocking means for preventing more than one of said-relays being energized at one time, andmeans for controlling said other circuit by said one relay and controlling said one circuit by said other 1 v relay; 7 r V I V 10. In an absolute-permissive-block signaling system for railroads, a single track section, sig-' nals at each end of said section for governing the entrance and exit of trains into and out of said section, signals at an intermediate point for governing the movement of trains in both directions through said section, a circuit leading from one end of said section to said intermediate point for a 1 I I at times. controlling a signal at said intermediate point, another circuit leading from the other end of said section to said intermediate point for at times, controlling a signal at said intermediate point and at other times controlling a signal at said other end, track circuits having qfront con tacts included in said circuits, two relays located at said intermediate point one at times included in one of said circuits and the other at times in lays being energized at one time, and means for controlling said other circuit by said one relay and controlling said one circuit by said other relay.

11. In a single track railway signalling system, the combination with a single track section, signals for governing traffic in each direction through said section, manually controllable means for determining the clearing of signals for establishing a particular direction of traffic through said section, and other manually cOntrollable means for reversing the direction of traffic set up by said first mentioned manually controllable means through said section, said other manually controllable means being effective irrespective of said first mentioned manually controllable means.

12. In an absolute-permissive-block signal system, the combination with a single track section, signals for governing the movement of trains through said section, means for controlling said signals including two circuits arranged end to end and together extending the length of said section, means for at one time directly contrlling one of said circuits by the other circuit and at other times directly controlling said other circuit by said one circuit, and two stick relays for determining which of said two circuits shall control the other of said two circuits.

13. In a single track railway signalling system,

the combination with a single track section having an intermediate signal location, a signal at said location for governing traific in one direction, a signal at said location for governing trafhe in the opposite direction, a relay for each signal to control the same, and a circuit for each relay including a back contact of the other relay and said circuit being energizable only when the track in advance of the signal for that relay is unoccupied by a train, whereby only one of said signals can be cleared .at one time.

14. In a single track railway signalling system, the combination with a single track section having an intermediate signal location, a signal at said location for governing trafiie in one direction, a signal at said location for governing traffic in the opposite direction, av relay for each signal to control the same, circuit wires for each relay, and contacts on each relay which if down connect the circuit wires of the other relay to such other relay but if up connect such wires to a source of current. 7

15. In a single track railway signalling system,

the combination with a single track section con-'- necting two double track sections, intermediate signal locations each including two signals one governing traffic in one direction and the other governing traflic in the other direction, a circuit extending from each signal location to an adjacent signal location, and means for controlling each circuit directly by the adjacent circuit to constitute a tumble-down arrangement which at times operates from right to left and at other times operates from left to right.

16. In a single track railway signalling system, the combination with a single track section connecting two double track sections, intermediate signal locations each including two signals one governing traffic in one direction and the other governing trailic in the other direction, a circuit extending from each signal location to an adjacent signal location, a relay for each end of each of said circuits, means for at times energizing each circuit from the right-hand end to energize the relay at the left-hand end and for at other n times energizing each circuit from the left-hand end to energize the relay at the right-hand end, and contacts on said relays for controlling each of said circuits by an adjacent circuit.

17. In a single track railway signalling system, the combination with a single track section con-' necting two double track sections, intermediate signal locations each including two signals one governing traffic in one direction and the other governing traffic in the other direction, a circuit extending from each signal location to an adjacent signal location, a relay for each endof each of said circuits, means for at times energizing each circuit from the right-hand end to energize the relay at the left-hand end and for at other times energizing each circuit from the left-hand end to energize the relay at'the right-hand end, a directional stick relay associated with each end of each of. said circuits, and contacts on said directional stick relays for at times applying current to said circuits.

18. In a single track railway signalling system, the combination with a single track section connecting two double track sections, intermediate signal locations each including two signals one governing traffic in one direction and the other governing traflic in the other direction, a circuit extending from each signal location to an adjacent signal location, a directional stick relay for each signal, and contacts on said directional stick relays for at times energizing said circuits from one end and 'at other times energizing said circuits from the other end.

19. In a single track railway signalling system, the combination with a single track section connecting two double track sections, intermeditrollable from a central oflice for permitting clearing of signals for only one direction of travel at one time, andother manually operable control means at each end of said single track section for changing the direction of traific set up by said first mentioned manually operable means.

20. In a single track railway signalling system, the combination with a single track section connecting two double track sections, intermediate signal locations each including two signals one governing traific in one direction and the other governing traffic in the other direction, a circuit extending from each signal location to an adjacent signal location for governing said signals, manually operable control means controllable from a central ofiice for permitting clearing of signals for only one direction of travel at one time, other manually operable control means at each end of said single track section for changing the direction of traific set up by said first mentioned manually operable means, and visual indicating means for indicating when the direction of trafiic has bee changed.

21. In a single track railway signalling system, the combination with a single track section connecting two double track sections, intermediate signal locations each including two signals one governing trafiic in one direction and the other governing traffic in the other direction, a circuit extending from each signal location to an adjacent signal location for governing said signals, manually operable control means con:

trollable from a central ofiice for permitting clearing of signals for only one direction of: travel at one time, other manually operable control means at each end of said single tracksectionfor changing the'direction of traific set up by said first mentioned manually operable means, and visual indicating means effective only so long -as said other manually operable'control means is in its operated'condition for indicating when the direction of traffic has been changed.

7 22(Route control means for allowing railway trafiic to move in one direction at one time only over a particular section comprising; a circuit connecting the ends of said section, a first relay at each end of said circuit for manifesting energization of said circuit, a second relay at each end of said section for energizing said circuit from that end, and means for interlocking said first and said second relay at each end of 'said circuit so that said'circuit cannot be conditioned t o be energized from that'end if it has already been energized from the other end.

23 Route control means for allowing railway traffic to move in one direction at one time only over a particularsection comprising, a circuit connecting the ends of said section, a first relay at each end of said circuit for manifesting energization of said circuit, a second relay at each end of said section for energizing saidlcircuit from that end, and means for interlocking said first and said second relay at each end of said circuit so that when said circuit is energized from one end such energization cannot be interfered" With'by the second relay at the other end. 24. In combination, a stretch of single track over which traflic moves in both directions, signals governing the entrance of trafiic into said stretch, intermediate signals located at intervals along the stretch for governing traific in' both directions through" the stretch, all of said signals being capable of indicating stop, caution, and proceed,Imanual1y operable means for separately controlling the signals'governing the entrance of traffic-into said stretch, in either-direction, and-l means for rendering said manually operable means'inefiective' to cause such entering signals to indicatecaution or proceed unless all of the opposing intermediate signals indicate s p. a

25. In combination, a stretch of, single track' over which trafiic moves in both directions, a first H signal for governing trafiic in one direction when said first line relay is energized by current of one polarity and a proceed indication when said first line relay is energized by current of the other polarity, a second signal for governing trafiic in the opposite direction through said stretch, a second polarized line relay; means con trolled by said second line 'relayfor controlling s'aidsecond signal in such manner that said second signal indicates stop, caution, or proceed according as said second line relay is deenergized or is energized by current of one polarity or the other; manually operable means for at times supplyingisaid second line relay with current of one polarity or the other when the portion of said stretch between said signals is unoccupied,

and means'for at times supplying said first line.

relay'with current of one polarity orithe, other when the'portion of said stretch between said aocasaa signals is unoccupied and said second line relay is deonergized. r a,

'26. In combination, a stretch of single track over which traffic moves in both directions, a first signal for governing traffic in one direction through said stretch, a first polarized line relay, means efiective when said first line relay is deenergized for causing said first signal to indicate stop, manually operable means for causing said first signal to display a caution indication, when 7 said first line relay is energized current of one polarity and a proceed indication'when said first line" relay is energized by current of the other 1 polarity, a second signal located'at some distance from said first signal for governing trafiic in the opposite direction through said stretch,-

a second polarized line relay; means controlled 7 by said second line relay for controlling said second signal in such manner that said second signal indicates stop, caution, or proceed according as said second line relay is deenergized or is energized by current of one polarity or the other; manually controlled means for at times supplying'said' second line relay with current of one polarity or the other when the portion of said stretch between said'signals is unoccupied, means for supplying said first line relay with current of one polarity when the portion of track between said signals is unoccupied and said second line relay is deenergized; and means for supplying said first line relay with current of the other polarity when the portion of track between said signals is unoccupied, said second line relay is dee-nergized, and the portion of track immediately beyond said the opposite direction from that governed by. said second signal is occupied.

27. In combination, a stretch of single track 'over which traffic moves in both directions, a first signalior governing trafiic in one direction through saidstretch, a first polarized line relay meansefiective when said first line relay is deenergized for causingsaidfirst signal to indicate stop, manually operable means for, causing said first signal to displaya, caution indication when said first line relay is energized by current of one polarity and a proceed indication said first line relay is energized by our ent of the other polarity, a second signal located at some distance, from said first signal for governing traffic in the opposite; direction through. said stretch, a second polarized line relay; meanscon' trolled by said second line relay for controlling said second signal in such manner that said second signalindicates stop, caution, or proceed according as said second line relay is deenergized or is energized by current of one polarity or the other; manually operable means for at times supplying said second line relay with current of one polarity or'the other when the portion of said nd signal for trafiic moving in stretch between said signals is unoccupied, and,

said first linerelay is deenergized, and means for" attimes supplying, said first line, relay with current of one polarity or the other when the portion of-said stretch between said signals is un- 7 occupied and said second line relay is deener- V gized.

28. In combination, a stretch of single track signal indicates stop when the relay is deenergized, and means for controlling said relays in such manner that a relay associated with a signal which controls traffic in one direction cannot become energized unless the relay associated with the opposing signal which governs the entrance of traific into the same portion of the stretch is deenergized.

29. In combination, a stretch of single track over which traflic moves in both directions, signals for governing traffic in one direction through said stretch and other signals for governing traffic in the other direction through said stretch, a plurality of line relays one associated with each signal and each arranged to control the associated signal in such manner that the associated signal indicates stop when the relay is deenergized, and means for energizing each line relay when and only when the portion of track between the associated signal and the signal next in advance governing traffic in the same direction is unoccupied and the line relay associated with the signal next in advance governing traflic in the opposite direction is deenergized.

30. In combination, a stretch of single track over which trafiic moves in both directions, head block signals governing the entrance of traffic into said stretch, intermediate signals located at intervals along the stretch for governing traffic in both directions through the stretch, a plurality of line relays one associated with each of said signals and each arranged to control the associated signal in such manner that the associated signal indicates stop when the line relay is deenergized, and means for controlling said line relays in such manner that the line relay associated with each head block signal cannot become energized unless all of the line relays associated with the intermediate signals which control traffic in the opposite direction are deenergized and all of the line relays associated with the intermediate signals which control traflic in the same direction are energized.

31. In combination, a stretch of single track over which trafiic moves in both directions, signals for governing trafiic in one direction through said stretch and-other signals for governing traffic in the other direction through the stretch; a plurality of line relays one associated with each signal and each arranged to control the signal with which it is associated in such manner that the signal will indicate stop, caution, or proceed according as the associated relay isdeenergized or is energized by current of one polarity or the other; means for at times supplying each line relay with current of one polarity when the portion of track between the signal controlled thereby and the signal next in advance governing traffic in the same direction is unoccupied, the line relay associated with the signal next in advance governing trafiic in the same direction is energized, and the line relay associated with the signal next in advance governing trafiic in the opposite direction is deenergized; and means for at other times supplying each line relay with current of the opposite polarity when the portion of track between the signal controlled thereby and the signal next in advance governing traffic in the same direction is unoccupied, the line relay associated with the signal next in advance governing trafiic in the same direction is deenergized; and the line relay associated with the signal next in advance governing traflic in the opposite direction is deenergized.

32. In combination, a stretch of single track over which trafiic moves in both directions; a first signal for governing traflic in one direction through said stretch; a first polarized relay for controlling said first signal to the clear, caution and stop condition when said first relay is respectively energized by current of normal polarity, by current of reverse polarity and is deenergized; a second signal for governing traffic in the opposite direction through said stretch, a second polarized relay for controlling said second signal to the clear, caution and stop condition when said second relay is respectively energized by current of normal polarity, by current of reverse polarity and is deenergized, control circuits for each of said polarized relays so organized that each saidrelay may be energized by current of either normal or reverse polarity if said stretch is unoccupied and the other of said relays is deenergized, and manually operable means for holding either of said relays deenergized.

33. In combination, a stretch of railway track divided into sections, signals governing traflic in both directions through said stretch, a polarized line relay and a slow-releasing stick relay for each signal, means operating when a given line relay is closed and the associated stick relay is open to supply current of normal polarity to the line relay for the signal next in the rear, means operating when the associated stick relay is closed to supply current of reverse polarity to the line. relay for the signal next in the rear independently of the given line relay, track circuits for said sections for controlling said line relays, means for energizing each stick relay when a train moving in the direction in which the associated signal governs traffic passes such signal and for keeping it energized as long as the line relay for such signal remains deenergized, and means controlled by each polarized line relay for energizing the associated signal to display a clear or caution indication when'its line relay is energized by current of normal or reverse polarity, respectively and to display a stop indication when its line relay is deenergized.

34. In combination, a stretch of railway track divided into a forward block and a rear block and the forward block further divided into a forward section and a rear section, a forward signal and a rear signal for governing traffic movements through the forward and rear blocks, respectively, a track circuit for each of the sections of said forward block each including a track relay, a line relay for controlling said forward signal energized by a circuit including in series contacts closed by said track relays in their energized condition,

a polarized line relay for controlling said rear signal, a slow-releasing stick relay, a circuit controlled by a front contact of said first line relay and by a back contact of said stick relay for energizing said polarized line relay by currentof normal polarity, a second circuit controlled by a front contact of said stick relay for energizing said polarized relay by current of reverse polarity independently of said first line relay, a pick-up circuit for energizing said stick relay when a train moves from said rear block into said forward block, and a stick circuit for said stick relay controlled by a back contact of said first line relay.

35. In combination, a stretch of railway track, signals located at intervals to govern traffic in one direction through the stretch, other signals located at intervals to govern traflic in the opposite direction through the stretch, a sectionalized line wire adapted for use as the common line wire in the control of said signals, a traffic locking circuit for the stretch having as one conductor the diiierent sections of said sectionalized line wire, directional means at each end of the stretch to govern trafiic entering the stretch at. its end and each arranged to beat times controlled': by the 'trailic locking circuit, a current source at each end' of the stretch each adapted to at tlmessup ply current to the trafiic'locking circuit for controlling the directional means at the opposite end of the stretch, and repeating means including two directional relays at each sectionaliz'ed location of said line wire said relays being arranged to bridge the traffic locking circuit from one section of the line wire to the next section'in either direction and thereby carry through from end to end of the stretch the control effected by'the current'source at one end to the directional means at the other end in either direction.

36. In combination, a stretch of railway track, signals located at intervals to govern traflic in one direction through the stretch, other signals located at intervals togovern traffic in the opposite direction throughthe stretch,a' sectionalized line wire adapted for use as the common line wire in the control of said signals, a trafiic locking circuit for the stretch having as one conductor 7 the different sections of said sectionalized line wire, directional means at each end of the stretch to govern trafiic entering the stretch at its'end and each arranged to be at times controlled by the traflic locking circuit, a current source at each end of the stretch each adapted to at times supply current to the traflic locking circuit for controlling the 'directionalmeans at the opposite end of the stretch, and repeating means including two directional relays at each 'sectionalized 1o'ca tion of said line wire and arranged to repeat the effect of the traffic locking circuit from one section of said line wire to the next in either direction and thereby carry through from end to end of the stretch the control eifected by the current a source at one end to the directional means at the other'end'in either direction. 7

'37. In combination, a stretch ofrailway track,

signals located atintervals to govern traflic in one direction throughthe stretch, other'signals located at intervals to govern trafic in the opposite direction through the stretch, a sectionalizedline wire adapted for uselas the common line wire control of said signals, a'ltrafiic locking circuit for the stretch having as one conductor the different sections of said sectionalizedcommon line wire, a current source and a relay at each end of the stretch, a manually controlled selector at each end adapted to include either the relay or the current source at its end in the traffic looking circuit, repeating means at each sectionalized location of the common line wire including two directional relays controlled by the trafilc locking circuit'and arranged to repeat the effect of the traiilc locking circuit from one section of the common line Wire to the next in a direction corresponding to the direction from which said'relays are controlled to carry through theinfluence effected by the applying of current to the traific locking circuit at one end to the relay at the other end, a signal at each end of the stretchtc govern the movement of trafiic 'into the stretch,

and means controlled by the relay at the same endof the stretch for'clearing said signal.

38. In combinatioma'stretch of railway track, 7

signals located at intervals to govern traffic in one direction through the stretch, other signals located at'intervalsto govern trafiic in the oppo site directionthrough the stretch, asectionalized 'line wire for the stretch adapted for use as the common 'line wire in the control of said signals, a trafiic locking circuit for the stretch arranged intoa plurality of sections each section'of which includes a corresponding section of said common line wire, a relay'and a'current source at each end of the stretch, a manually controlled selector at each end adapted to include either the relay or the current source at its endin the'trafiic locking circuit, 'repeating'means at eachjunction 'of adjacent sections of the traflic locking circuit including two directional relays controlled by the traffic locking circuit and arranged to repeat the effect of the trafilc locking circuit from one section to the next'in the direction corresponding to that from which said relays are controlled to carry through'the influence effected by applying current to the trafiic locking circuit at either end of the stretch to the relay at the other end; a signal at each end of the stretch to govern the movement of traflic intothe stretch, and.

means controlled by the relay at the same end of the stretch for clearing said signal.

39. In combination, a stretch of railway track, signals located at intervals to govern trafiic in one direction through the stretch, other signals located at intervals to govern trafiic in the opposite direction through the stretch, a sectionalized line wirefor thestretch adapted for use as the" 7 common line wire in the control of said signals, a traffic locking circuit for the stretch arranged into a plurality of sections each section of which includes a corresponding section of said common line wire, a relay and a current source at each' end of the stretch, a manually controlled selector at each end adapted to includeeither the relay or the current source at its end in the trafiic looking circuit, repeating meansat each junction of adjacent sections of the traffic locking circuit including two directional relays controlledby the traiiic locking circuit and arranged to supply current to either adjacent section in response to being controlled from the other adjacent section, to thereby carry through the influence effected by applying current to the trafiic locking circuit at either end of the stretch to the relay at the other end, a signal at e'achend; of the stretch to govern the movement of trafiic into the stretch,

and meansv controlled by the relay at the same end of the'stret'ch for clearing said signal.

40. In combination, a stretch of railway track, signals located at intervals to govern trafiic in one direction through the stretch,"0ther signals located at intervals to govern trafiic in the opposite direction through the stretch, a sectionalizcdl line wire for the stretch adapted for use as the common line wire in the control of said signals,

a traffic locking circuit for the stretch arranged into a plurality of sections each section of which includes a corresponding section of said common line wire, means at each end of the stretch each tion to thereby supply current to the relay at} either end of the stretch in response to current supplied to the traflic locking circuit at the end opposite that relay.

41. In combination, a stretch of railway track arranged into track sections each of which is provided with the usual track circuit including a track relay, a trafiic locking circuit extending along the stretch arranged into a plurality of different sections with each section including a front contact of each track relay oi the track sections adjacent that section of the traffic locking circuit, a source of current and a directional relay at each end of the stretch, manually controlled means at each end to include either the current source or the relay at its end in the trafiic looking' circuit, repeating means at each junction of adjacent sections of said traffic locking circuit including a current source and two directional relays controlled by the traffic locking circuit and arranged to supply current to either adjacent section when controlled by current from the other adjacent section whereby under clear traffic conditions the relay at either end of the stretch will become energized when current is supplied to the traific locking circuit at the other end, a signal at each end of the stretch to govern the movement of traiiic into the stretch, and means controlled by the relay at the same end of the stretch for clearing said signal.

42. In combination, a stretch of railway track arranged into track sections each of which is provided with the usual track circuit including a track relay, a traffic locking circuit extending along the stretch arranged into a plurality of diiierent sections with each section including a front contact of each track relay of the track sections adjacent that section of the trafiic locking circuit, a source of current and a directional relay at each end of the stretch, manually controlled means at each end to include either the current source or the relay at its end in the trafiic locking circuit, repeating means at each junction of adjacent sections of said traffic locking circuit including two directional relays controlled by the trafiic locking circuit and arranged to supply current to either adjacent section when controlled by current from the other adjacent section, to thereby carry through under clear traific conditions of the stretch the influence effected by supplying current to the traific locking circuit at one end of the stretch to the relay at the opposite end for energizing that relay, a signal at each end of the stretch to govern the movement of traflic into the stretch, and means controlled by the relay at the same end of the stretch for clearing said signal.

43. In combination, a stretch of railway track divided into track sections each of which is provided with the usual track circuit including a track relay, signals located along said stretch and arranged to govern traflic in both directions, a sectionalized line wire for the stretch adapted for use as the common line wire in the control of said signals, a traffic locking circuit for the stretch arranged into a plurality of sections each section of which includes a corresponding section of the sectionalized line wire and a front contact of the track relay of each track section adjacent that section of the traffic locking circuit, means at each end of the stretch adapted to at times supply a control current to the trafiic locking circuit, a directional relay at each end of the stretch controlled by the trafiic locking circuit, two directional relays at each junction of adjacent sections of the traffic locking circuit controlled by said circuit and arranged to supply current to one adjacent section when controlled by current from the other adjacent section and to supply current to said other adjacent section when controlled by current from said one adjacent section for energizing the relay at the end of the stretch opposite that at which current is supplied to the trafiic locking circuit, a signal at each end of the stretch to govern the movement of traffic through the stretch, and means for clearing said signal when the relay at its end of the stretch becomes energized.

44. In combination, a stretch of railway track divided into sections, a track circuit incuding a track relay for each track section, a line circuit for the stretch divided into sections each including front contacts of the track relays of the track sections adjacent such line circuit section, a source of current and a directional relay at each end of each section of the line circuit, manually controlled means at each end of the stretch for selectively including in the section of the line circuit having one end adjacent said means the source of current or directional relay at that end of said section, means at each junction oi adjoining sections of the line circuit for including in each of said sections the source of current or directional relay at the adjacent end of such section according as the directional relay at the adjacent end of the other adjoining section is energized or deenergized, a signal at each end of the stretch to govern the movement of trafiic through the stretch, and means controlled by the directional relay at the same end for controlling said signal.

45. In combination, a stretch of railway track, a signal at each end of the stretch to govern the movement of trafiic through the stretch, a line circuit for the stretch divided into sections, a source of current and a directional relay at each end of the stretch, manually controlled means at each end of the stretch for selectively including in the end section of the line circuit adjacent said means its source of current or directional relay, repeating means at each junction of adjoining sections of the line circuit efiective to include a source of current in either of said sections at the end adjacent such junction when the other adjoining section is energized at the end remote from such junction, and means controlled by each directional relay for clearing the signal at the same end of the stretch.

46. In a signaling system for railroads, the combination with a section of railway track over which traific moves in both directions, signals for governing trafiic in both directions over said section, a signaling circuit associated with said section, two relays one at each end of said circuit, each of said relays being of the polar-neutral type opening its neutral contacts when deenergized, means for connecting one or the other of said relays to said circuit according to the direction in which traffic is to move over said section, means controlled by neutral and polar contacts of said relays for governing said signals, and means controlled by the presence of a train in said section for opening said circuit to deenergize the one of said tworelays then connected to said circuit and thereby cause the corresponding signal to indicate stop so long as said section is occupied.

WALTER W. WENHOLZ.