US1400964A - Railway-traffic-controlling apparatus - Google Patents

Description

R. A. McCANN.

RAILWAY TRAFFIC CONTROLLING APPARATUS.

APPLICATION F LED APR-Z3. 1919.

Patented Dec. 20, 1921.v 3 SHEETS-SH INVENTOH 1,400,964. A w a R. A. McCANN.

RAILWAY TRAFFIC CONTROLLING APPARATUS.

APPLICATION FILED APR.23., 1919.

1,400,964, I Patented Dec. 20, 1921.

3 suziTs-suzn 2. 'L

INVENTOR N I Atty.

R. A. McCANN.

RAILWAY TRAFFIC CONTROLLING APPARATUS.

APPLICATION FILED APR. 23, I919.

1,400,964. Patented Dec. 20, 1921.

U 3 SHEETS-SHEET 3.

7 9.9: T S D 1 C r O---\ I l INVENTOR EQW UNITED STATES PATENT OFFICE.

RONALD A. MGCANN, OF SWISSVALE, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH 1% SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORA- TION OF PENNSYLVANIA.

RAILWAY-TRAFFIG-CONTROLLING APPARATUS.

Application filed April 23, 1919. Serial No. 292,186.

To all whom it may concern Be it known that I, RONALD A. MCCANN, a citizen of the United States, residing at Swissvale, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Railway- Traffic-Controlling Apparatus, of which the following is a specification.

My invention relates to railway trafliccontrolling systems, and particularly to systems ofthe type wherein alternating traffic controlling current or" currents are supplied to the track rails, and the cars or trains are provided with governing apparatus which is controlled by such current or currents in the rails. More particularly, my invention relates to trackway circuits and apparatus whereby systems of this type may be applied to single track railways over which traflic moves in both directions.

In one system of the type mentioned, it

- has been proposed to employ the usual track circuit current, that is, the current which energizes the track relays, as one of the currents for controlling the train-carried governing apparatus, the train governing apparatus being controlled by this current throughthe medium of I'GCGIVIIIO' appliances at the front end of the train. when this is done, it is obvious that the source of track circuit current must always be connected across the track rails ahead of a train. This requirement is readily met in double track railways wherein traffic on eachtrack moves in one direction only, because the source of track circuit current for each track section can then be constantly connected across the rails at the leaving end of the section, this being in fact in accordance with-standard practice in automatic block signaling. In the case of a single track railway, however, this standard practice cannot be followed because a train entering a track section at the end at which the source of current is located would obviously shunt such current away from its own receiving -appliances. One feature of my invention, then, is the provision of train-controlled means for connecting a source. of track circuit current with the rails at one end or the other of a section Specification of Letters Patent.

\ Patented Dec. 20, 1921.

rails in such manner that it flows in the same depending on the direction in which the direction in the two rails, which current coacts with the track circuit current to con trol the train governing apparatus. The supply of this traflic controlling current to the track rails is controlled by traffic conditions in advance, and so for single track systems there must be two such sources of current for each section, and two sets of devices for controlling its supply to the rails of the section. Another feature of my invention, then, is the provision of train-controlled means for each section for selecting the source of traffic controlling current and the devices for controlling its supply in accordance with the direction in which the train 1s moving.

I will describe one form and arrangement of trackway apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fi res 1, 1 and 1", are diagrammatic views s owing one form and arrangement of trackway apparatus embodying my invention, it being understood that a complete system can be formed by placing these views end to end in the order named.

Referring to the drawings, the reference characters 2 and 2 designate the track rails of a stretch of single track, which rails are divided by insulated joints 3 into a lurality of successive sections'A-B, B( C-D, etc. track here shown two passing sidings G and G are provided, one in section AB and the other in section E-F. The portion of track B-E between these sidiligs may for conveniencebe termed a block.

Trafiic along the railway from east to west is governed by roadside signals S, S, S", S, S and S, while traflic from west to east is It will be noted that in the stretch of similarly governed by signals S S, S", S,

- S and S. In the arrangement here shown,

junction of adjacent track sections, but I do no desire to limit myself to this particular location of the signals.

Each track section' is provided with a track circuit comprising two track relays and a source of track circuit current. Considering section C-D, for example, two track relays T and T are connected across the track rails adjacent the ends C and D of the section respectively, and the secondary of a transformer H is also connected across the rails adjacent end C. The track relay T is constantly connected with the rails, but the track relay T is at times disconnected from the rails by a relay J and another transformer H connected across the rails in its place. At such times, transformerH is also disconnected from the rails by a relay K. The operation of relays J 7 and K will be explained hereinafter, but for present purposes it may be assumed that relays T and T and transformer H are constantly connected with the rails. Each section is provided with apparatus similar to that in section CD, the exponents for the various parts corresponding to the exponents of the adjacent signals.

Means are also provided for supplying the second or trafiic controlling current to the rails of the several sections, but before explaining this means I will explain the control of the signaling system and also the means for providing a source of track circuit current ahead of a train regardless of the direction in which the train is moving.

The roadside signals are controlled in accordance with what has become known in the art as the Absolute-permissive signaling system, that is, a system for preventing two trains moving in opposite directions from entering the same bloclgbut for permitting two or more trains moving in the same direction to pass through a block under the same signal protection as on a double track road.

Each signal S is of the three-position type. adapted to indicate stop, caution or proceed, according as the semaphore is in the horizontal, inclined or vertical position. Each signal is provided with a line relay which is designated by the reference character R. with the same exponent as that of the corresponding signal, and each of which relays is of the three-position polarized type.

That is, each of these relays comprises armature contacts 4, 5 and 6 (see relay R in Fig. 1".) which are arranged to assume vertical positions when the relay is deenergized, and are arranged to swing to the right or to the left according as the relay is energized by current of normal or reverse polarity. As here shown, each relay R comprises only one winding, but inasmuch as these relays are controlled by alternating current. it is, of course, understood that each relay must also include a polarizing winding which is constantly supplied with alternating current. The polarizing windings are omitted from the drawings for the purpose of simplification.

Each signal is provided with a caution indication circuit and a proceed indication circuit, the former or the latter of which is closed according as the corresponding relay R is energized in reverse or normal direction. For example, referring to signal S the cantion indication circuit is from one terminal of a suitable source of current, through left-hand point of contact a of relay R wire 7, operating mechanism of signal 5 wire 8, and left-hand point of contact 5 to the other terminal of the same source of current. The proceed indication circuit for this signal is from terminal through right-hand point of contact 4, wire 9, signal mechanism, wire 8 and right-hand point of contact 5 to terminal Each signal is controlled by the corresponding relay It in a similar manner.

The line relay R for signal S is controlled by the two track relays for section C-D and by the line relay R for signal S. The circuit for this relay R is from a transformer L through a pole-changer P operated by si nal S wires 10 and 11, contact 6 of relay it wires 12 and 13, contact 1-1 of track relay T, wire 15, contact 18 of track relay T. wire 19, relay R and wires 20 and 21 to pole-changer P and transformer L Pole-changer P supplies current of normal polarity'to this circuit while signal S is in the proceed or caution position, and current of reverse polarity when said signal is in stop position, hence it will be seen. that, disregarding the function of relay R in the circuit, the control of signal S is in accordance with double track signaling practice.

The line relays for signals S 8* and S are controlled in the same manner as the line relay R for signal S. The line relay for signal S is controlled by the two t 'ack relays T 4 and T for section B- C, and by the contacts of a special pole-changing relay M the function and control of which are hereinafter explained. The line relay R for signal S is similarly controlled by the two track rel: ys T and T for section D E. and by a special relay M The control of the line relays for signals 8 S. S and S will he explained hereinafter.

It follows from the foregoing that when an eastbound train enters block B E. the consequent opening of track relay T opens the circuit for line relay R and so places signal S at stop. Linc relay it opens the circuit for line relay R and so places signal S at stop. and line relay R opens the circuit for line relay It" and so places signal S at stop. Furthermore. with only the apparatus thus far described. it will be seen that when a westbound train passes point will remain at sto until the train leaves the block at point T 0 permit a second train to follow such a west-bound train through the block BE, means are )rovided for removing line relays R and 7 from control by relays R and B respectively, which means comprises the relays K and K Considering relay R the circuit for this relay is provided with a shunt around contact (lot line relay R, which shunt is from wire 10, through wires 22 and 23, contact 24 of relay K and wire 25 to wire 13. Relay K is normally deenergized, but becomes energized when a west-bound train passes signal S. This relay is provided with a pick-up circuit which passes from the terminal of a suitable source of current, through back contact 26 of track relay T, wire 27, back contact 28 of relay T. wire 29, contact 102, wire 29, and winding of relay K to the terminal of the same source of current. It will be secn,thcreforc, that this relay becomes energized just as the forward end of the train enters section CD, at which time both trackielays T and T are deenergized, provided that signal S, which operates contact 102, is at proceed or caution. Relay K is provided with a holding circuit which passes from the terminal of a suitable source of current, through back contact 30 of track relay T, wire 31, front contact 32 of relay K wire 33, and thence through the winding of relay K to the terminal of the same source of current. It follows, then, that when this relay has once become energized, it will remain energized as long as track relay T is open; that is, until the entire train has passed out of section CD.

The circuit for line relay R is removed from control by line relay R by virtue of relay K in a similar manner. The same thing is true of the controlling circuits for line relays R and R.

I From the foregoing it will be clear that when a west-bound train passes signal S. signal S will move to the caution position, and that when such train passes signal S signalS will move to the caution position and signal S will move to the proceed position. Similarly, when an east-bound train passes signal S, signal S will move to the caution position, and when such train passes signal S signal S will move to the caution position and signal S will move to the proceed position.

The line relay R for signal S is controlled by the two track relays T and T of section A-B and also by track relay T, the circuit being from transformer L, through pole-changer P, wires 34, 35 and 36, contact 37 of track relay T, wires 38 and 39, contact 40 of'track elay T ,.wire 41, contact- 42 of track relay T wire 43, winding of relay R and wires 44. and 45 tofpolechanger P and transformer L. It follows from this that when section AB is unoccupied and signal S indicates proceed,signal s likewise indicates proceed; whereas, when signal S indicates stop and track relay T is energized, signal S indicates caution. That is, when an east-bound train enters the block to the left of mint A and so places signal S at stop, signal S will indicate caution. In order to permit signal S to move to the caution position as soon as a west-bound train has passed signal P, the circuit' for relay R is provided with a branch around the contact 37 of track relay T which branch is controlled by relay K; relay K is controlled in the same manner as relay K hereinbefore explained.

It is desirable that when an east-bound train occupies the block to the left of point A, signal S", as well as signal S should indicate caution, but that when "a westbound train has passed signal S, thus allowing signal S to moveto caution position, signal should return to the full proceed position. The reason for this is well understood by those familiar with the art. This control of signal S isaccomplished by relay M As hereinbefore pointed out, the circuit for line relay R is controlled "by the pole Changing contacts of relay M so that when section BC is unoccupied signal indicates proceed or caution according as relay M is ener ized or de'c'nergized. The normal circuit for relay M is from transformer L through pole-changeiuP, wires 34 and 46, contact 47 operated by signal S, wires 48 and 49, contact 50 operated by signal S, wire ol, winding of relay M wires.52,'53, l4 and 45, thence through pole-changer P to transformer L. This circuit is provided with a branch around contact 47, which branch is from wire 34, through wires 34, 35, 54, 55 and 56, contact 57 of relay K,

and wire 58 to wire 49. It follows from this that when an east-bound train enters the block to the left of point A, the movement of signal S to thestop position opens con tact 47 and so deenerglzes relay M where- 'upon signal S moves to the caution position.

When a west-bound-train, however, passes signal S relay K becomes energized, thus closing the shunt around, contact 47 so that relay M immediately becomes energized, whereupon signal S moves to the full proceed position.

signals 8", S and S are controlled in the same manner as signal S whereas signal S is controlled in the same manner as signal S". V

The operation of the signaling system as a whole is in accordance with the principles .of standard absolute permissive block signaling, and will be understood from the foregoing explanation.

As I have'already pointed out, the track circuit for section across the rails at end C, however, so that the traffic governing apparatus on the train is supplied with current from this transformer as long as the train is in the section. It will be seen, however, that in order to permit an east-bound train to pass through sections CD, means must be provided for connecting a source of current across the rails at the end D, as long as such train is in the section. As here shown, this is accomplished by relay J which connects the track relayT or a transformer H across the track rails at end D according as relay J T is deenergized or energized. The circuit for relay J is from transformer L through pole- changer P wires 10, 60 and 61, front contact 62 of relay K wire 63, back contact 64 of track relay T, wire 65, back contact 66 of track relay T wire 67, winding of relay J wires 68, 69, 20 and 21, and polechanger P to transformer L. henan east-bound train enters section C-D, it, of course, immediately de'c'nergizes both track relays T and T and if signal S is at proceed'or caution relay K will be energized, thus closing the circuit just traced for relay J and so disconnecting track relay T from the rails of the section and connecting transformer H across these rails at the end D.

' Current from transformer H is, therefore,

supplied to the vehicle-governing apparatus on the train as long as the train is in the section. When the entire train has left the section C-D, track relay T will again close, clue to the supply of current from transformer H whereupon relay K becomes deenergized and so again connects transformer H across the rails of the section at the end C. The closing of track relay T also deenergizes relay J so that transformer H becomes disconnected from the track rails and trackrelay T is again connected with the rails at the end I).

One important feature of the track circuit arrangement just described is that when the track circuit has become reversed due to an east-bound train entering section C-D, it will remain in the reverse condition as long as there is a train in the section, and will automatically restore itself as soon as the section becomes unoccupied. To explain.this more fully, relay K, when once energized, will remain energized as long as track relay '1 is deenergized. While relay K. is energized, it disconnects transformer H from across the terminals of relay T by opening the back point of contact 72. lVhen relay T is once deenergized, then, it is no longer connected with transformer H, but can be energized only by current received over the track rails from transformer 11, and this, of course, cannot occur. while there is a train in any part of the section. It follows, therefore, that relay T will necessarily remain deenergized, and that relays K and J 7 will necessarily remain energized, as long as, the train occupies section 0 -1). Relay T is, in effect, controlled as a stick relay, in' that when once disconnected from transformer H it can be'energized only by current from transformer H but after being thus energized it will continue to be energized from transformer H until relay It becomes closed.

Another important feature of the circuits as shown in the attached drawings is the use of line wire 65 (section C-D) as one wire of the circuit for line relay R and also as one wire for the circuit of the repeating relay J Were it not for this joint use of wire 65, an additional line wire would be required throughout the system. The wire 20 is, of course, common to the circuits for these two relays.

It will be noted that an impedance 59 is interposed between track rail 2* and the winding of relay T When relay K is energized, this impedance is shunted by a low resistance path which passes from point 70 through wire 71, front contact 72 of relay K and wire 7 3 to point 74. This impedance, then, is shunted out when relay K is energized. The reason for this is as follows:

WVhen the track circuit is in normal condition, that is, when the parts are as shown in the drawing, transformer H is connected across the rails at the same point as relay T. The impedance 59 is desirable at such time to avoid over-energization of relay T and under-energization of relay T When, however, the track circuit arrangement is reversed, that is, when transformer H is disconnected from the rails, and transformer H is connected with the rails atthe other end of the section, it would be undesirable to leave the impedance 59 in series with relay T because an undue amount of energy would then be required from transformer H to cause track relay T to close after an east-bound train passes out of the section.

I accordingly provide the means hereinbe-,

fore explained for shunting out the impedance 59 while the track circuit arrangement is reversed, with the result that only the normal amount of energy is required from transformer .11 to energize relay T when the east-bound train leaves the section.

The track circuit apparatus for each section of track is the same as the apparatus for section CD.

As already stated, the trackway apparatus herein'shown includes means for causing an alternating traific controllin current to flow along the two track rails each section in the same direction, which current is controlled by trafiic conditions in advance. This means is as follows:

Referringagain to section C-D, I will assume that a west-bound train enters the section and that signal S is in the proceed position as shown. As soon as this train enters the section, relay K becomes energized, and current will then flow from transformer L through pole-changer, P wire 75, cont-act 76 operated by signal S, wires 77 and 78 to the middle point of an impedance 79 connected across 'the track rails at the end C of section C-D, thence through the two track rails in multiple to a similar impedance 80 connected across the rails at end D, thence from the middle, point of this impedance throughwires 81 and 82, contact 83 of relay K, wire 84', back contact 85 of relay J, wire 86, back contact 87 of relay K, wires 88 and 21 and pole-changer P to transformer L When pole-changer P is in the position shown, that is, when signal S is in the proceed or the caution position, the current thus su plied to the track rails may be termed cur ent of normal polarity. I will now assume that when the west-bound train enters section .CD, signal S is in the stop position. Pole-changer P and contact 76 will then be reversed, so that current will flow in the following path-from transformer L through pole-changer P wire 75, contact 76, wire 89, impedance 90, thence through the track rails 2 and 2 in mutiple to impedance 80, and from there through the same path as before to transformer L The current thus supplied to the track rails may be termed current of reverse polarity, and it will be noted that this current is supplied to the rails onl between impedances 90 and 80, the impe ance 90 being located a considerable distance from the end C of the section.

I will now assume that an east-bound train enters section CD and that signal S is in the proceed position. The entrance of such a train upon the rails of section CD will cause energization of relays K and J, as hereinbefore explained. Current will then flow from transformer L through polechanger P wire 91, contact 92, wires 93 and 81 to the middle point of impedance 80, thence through the two track rails 2 and 2 in multiple to impedance 79, thence through wires 78 and 94, front contact 87 of relay K, wire 86, front contact 85 of relay J, and wires, 95, 96 and 97 v to pole-changer P and transformer L This current may be termed current of normal polarity. 'If signal S is in the stop position when the eastbound train enters section CD, the current from transformer L will. pass through polechanger P wire 91, contact 92, Wire 98, im

pedance 99, through the track rails 2 and 2 in multiple to impedance 79 and thence through the same path as before to transformer L Owing to the reversal of polechanger P this current will be of reverse polarity and will be supplied to the rails only between impedances 99 and 79, impedance 99 being located a considerable distance from end D of the track section.

The means for causing current to flow in the same direction along the two rails of section B-O is the same as the means just explained for section C-D in so far as concerns an east-bound train. When a westbound train passes through this section, however, this current is supplied by transformer L andits polarity is controlled by the pole-changing contacts of relay'M", so that this current is of normal or reverse polarity according as signal S? indicates 85 proceed or caution. Similar remarks apply to section D-E.

As for section AB, the means for supplying trafiic controlling current along the two rails is the same as the means for section 0-D in so far as concerns an ,eastbound train. There bein no stick relay K for signals, however, t e path for the traflic controlling current when a west-bound train passes through the section is taken through the track relay T, as follows: From impedance 80 through wires 81 and 82 back contact 85 of relay J wire 100, back contact 101 of track relay T and thence through wire 86 and the same path '100 as in section C-D to transformer Similar remarks apply concerning section E-F.

Before explaining the operation of the system as a whole, it should be pointed out I that the trackway apparatus here shown is 105 intended for cooperation with train-carried governing apparatus which operates in the following manner: When the train is on a portion of track which is supplied with track circuit current and also with traific controlling current of normal polarity, the governing apparatus permits the train to travel at high speed. such as 60 miles per hour. When the track is supplied with track circuit current, and also with trafiic controlling current of reverse polarity, the govern ing apparatus prevents the train from proceeding at more than an intermediate speed, such as 35 miles per hour. But when the train enters a portion of track to which the supply of either track circuit current or traflic controlling current is discontinued, the governing apparatus prevents the train from proceeding at more than a low speed,

such as 10 miles per hour. Qne form of governing apparatus which Wlll cooperate in this'manner with the trackway apparavember 21, 1918, Serial No. 263,607, for Railway trafiic controlling systems, now Patent No. 351,771, Sept. 7, 1920.

The operation of the entire apparatus is as follows:

I will first assume that an east-bound train enters the block which lies to the west of location A. Such a train causes signal S to move to the stop position, and this, in turn, causes signal S to move to the caution position. Relay M is then de'energized, so that signal S likewise moves to the caution position. The deenergization of relay M causes traflic controlling current of reverse polarity to be supplied to the rails of section BC, and the reversal of pole-changer P causes traffic controlling current of similar polarity to be supplied to the rails of section A--B. Signal S being in the stop position, traflic controlling current for section A-B flows through the rails between impedances 90 and 80*, but not between 7 9? and 90". With the first train in the block to the west of location A and moving toward the cast, I will assume that a second train, moving toward the west, enters block B--E. lVhen this second train passes point E, the deenergization of track relay T causes relay K to become energized, so that trafiic controlling current is supplied to the rails ,of section D E; inasmuch as signal S is in the proceed position, this current is of normal polarity and flows in the rails throughout the entire section. The westbound train may, therefore, proceed through this section 'at full speed. Similar conditions exist when the west-bound train enters section C-D. Signal S is in the caution position, but this does not affect the control of the traflic controlling current by le-changer P and contact 76. The westound train may, therefore, proceed at full speed through section C--D. As the westbound train enters section BC, it causes relay K to become energized, whereupon t'raflic controlling current of reverse polarity issupplied to the rails throughout the entire section. The train may, therefore, proceed through this section at or below the intermediate speed of 35 miles per hour. As the west-bound train enters section A--B, the deenergization of track relay T causes trafiic controlling current of reverse polarity to be supplied to the rails of this section between impedances 90 and 80 so. that the train may proceed as far as impedance 90 at or below the intermediate speed. After passing impedance 90, however, the influence of the trafiic controlling current is lost, so that the train cannot proceed beyond this point at more than the low speed 01510 miles per hour.

I will next assume that a west-bound I train enters block B-E and that after the entire train has passed point D a second 'west-bound train enters the same block.

\Vhile the first train is in section CD, signal S is in stop position, so that traffic controlling current of reverse polarity,- is supplied to the rails of section DE between impedances 90 and BU The second train may, therefore, proceed through section DE at the intermediate speed until it reaches impedance 90, whereupon its speed is reduced to the low value, or ten miles per hour. When the entire first train has passed into section B-C, the second train may enter section C -D at the intermediate speed, but is brbught down to the low speed upon passing'impedance 90. Then the first train has passed entirely into sec-tion A-B traffic controlling current of reverse polarity is supplied to .the rails of section BC between impedances 90 and 80, so that the second train can pass through this section in the same manner as through section CD. If the first train passes entirely into the section to the west of point A before the second train enters section B-C, however, this second train can then proceed through sectionB-C at the high speed, because relay M has become energized, and, consequently traificcontrolling current of normal polarity is supplied to the rails of section B-C throughout the entire length of this section.

The operation of the apparatus during the passage of trains through block B-E in the opposite direction is similar to that just described for the passage of west-bound trains through, this block, and hence no further explanation is required.

It will be observed that when track section CD is occupied by a west-bound train, trailic controlling current flows through the two rails of the section in the same direction in the rear of the train.. If this current should be sufliciently unbalanced in the two rails in the rear'of the train, due for example to a sufficient difference in the resistances of the two lines of rails, and should be 'of su'fiicient magnitude, the track relay T in the rear of the train might become falsely energized. At the same time the relay T in advance of the train might still 'be energized because it is connected directly with a source of current H and will not open immediately upon the entrance of a. train into the section. Assuming'this set of conditions to exist it .is apparent that signal S would indicate proceed, even though section CD is occupied by a train. To avoid the possibility of a false clear signal due to such a combination of circumstances, I have included the front contact 83 of stick relay K. in the circuit of the trafiic controlling current from trans-..

and when the entire train has. passed point I) this relay is held energized by a stick circuit which includes back contact of track relay T. If, now, track relay T should become falsely energized due to unbalanced traltic controlling current in the rear of the train, the opening of contact 30 would deenergize relay K, and this relay could not again become energized because its pick-up circuit would then be open at contact 102. The opening of relay K would immediately cut off the supply of traflic controlling current from the rails of section C-D, so that track relay T, would at once open and stay open. The train in section CD would then be compelled to proceed at 10 miles per hour or less, but would be protected by a stop signal ,in its rear.

The explanation given in the foregoing paragraph applies equally well to each of the other track sections shown in the d awings.

Although in many of the accompanying claims I have referred specificallyto track section C-JD, it is understood that this-is done only for the sake of elearness, and that the majority of such claims are readable on each of the other track sections shown in the drawings. 1

Although I have herein shown and described only one form of trackway appa *atus and circuits embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track, a track relay connected with the rails at one end of the section, a source of alternating current normally connected with the rails at the same end of the section, a track relay and a source of alternating current at the other end of the section the relay being normally connected with the rails, and means controlled by said relays when actuated by a train entering the section at the first-mentioned. end for disconnecting the first-men tioned source of current from the rails, and for disconnecting the second-mentioned relay from the rails and connecting the secondmentioned source of current with the rails.

52. In combination, a section C-D of railway track, a relay T connected with the rails at one end of the section, a source of alternating current H" normally connected with the rails at the same end of the section, a second relay T and a second source of alternating current H at the other end of the section said second relay being normally connected with the rails at the latter end, and means controlled by said relays when actuated by a train entering the section at the first-mentioned end for disconnecting source H from the rails, and for also disconnecting relay T from the rails and connecting source H with the rails.

3. In combination. a section of railway track, a source of alternating current adjacent one end of the section and normally connected across the track rails. a second source of alternating current adjacent the other end of the section and normally .disconnected from the track rails, and means controlled by a train entering the section from the firstmentioned end for disconnecting the firstsource from the rails and connecting the second source across the rails. said means being ineffective when a train enters the section from the opposite end.

4. In combination, a section of railway track, a relay connected with the rails adjacent one end of the section. a source of alternating current normally connected with the rails adjacent the same end and a second source of alternating current adjacent the other end of the section but normally disconnected from the rails. and means including said relay controlled by a train entering the section from the first-mentioned end for disconnecting said first source from and connecting said second source with the rails of the section.

5. In combination, a section 6-1) of railway track, two track relays T and T adjacent the ends of said section the former being constantly connected with the track rails, two sources H and H of alternating current adjacent the ends of said section, a relay J for connecting track relay T or source H with the rails according as the relay J is deenergized or energized, a relay K for connecting source H with the rails only when the relay is dei nergized, means for energizing relay J when both track relays are deenergized and relay K is energized, and means controlled by track. relay T for energizing relay K when a train enters the section at the end adjacent relay T and for keeping it energized until the train leaves the section, said means being ineffective to energize relay K when a train passes through the section in the opposite direction.

6. In combination, a section C-D of railway track, two track relays,T and T, adjacent the ends of said section the former being constantly connected with the track rails, an impedance interposed between relay T and one of the rails, two sources H and H of alternating current adjacent the ends of said section, a relay J for connecting track relayT or source H with the rails according as the relay J is deenergized or energized, a relay K for connecting source H with the rails only when the relay is deenergized and. for closing a shunt around said impedance when the relay is energized,

means for energizing relay J when both track relays are de'energized and relay K is energizerhand means controlled by track relay T for energizing relay K when a train enters the section at the end adjacent relay T and for holding it energized until the train leaves the section, said means being ineffective to energize relay K when a train passes through the section in the opposite direction.

7. In combination. a section C-l) of railway track, two track relays T and T ad jac-ent the ends C and D of said section respectively, the former being constantly connected with the rails and the latter being normally connected. with the rails, two sources of alternating current H and H adjacent the ends U and D of the section respectively, the former being normally connected with the rails, and means controlled by said track relays when actuated by a train ente 'ing the section from the end C for disconnecting source H and relay T from the rails and connecting source H with the rails, said means being ineffective when a train enters the section from. end D.

8. in combination, a section C-D of railway track, two track relays T and T adj acent the ends C and D of said section respectively, the former being constantly connected with the rails and the latter being normally connected with the rails, an impedance interposed between relay T and one of the track rails, two sources of alternating current H and H adjacent the ends C and D of the section respectively, the former being normally connected with the rails, and means controlled by said track relays when actuated by a train entering the section from the end (I for disconnectingsource H and relay T from the rails and connecting source H with the rails and closin a shunt 1 around said impedance, said means being ineffective when a train enters the stretch from the end D.

9. In combination, a stretch of rail ay track divided into a plurality of sections, signals for the sections for governing trafiic through said stretch in one direction, a line relay for each signal, means for controlling the line relay for each signal by the line relay for the signal next in advance, track circuits for the sections for the control of said line relays and each comprising a source of alternatingcurrent normally connected with the rails adacent the end at which the signal for the stretch is located and two track relays connected with the rails at opposite ends of the section, and means for each signal for removing the corresponding line relay from control by the line relay next in advance and for disconnecting the said source of current from the corresponding section and connecting a second source necessawith the rails at the opposite end of the section.

10. lin combination, a section C-ID of railway track, a line wire extending through such section, two sources of alternating current L and If adjacent the ends of said section. one terminal of each source being constantly connected with the two track rails of the section, a relay K for connecting said line wire with the remaining terminal source if or with the two track rails according as the relay is deenerg'ized or energized, a second relay J for connecting said line wire with the remaining terminal of source L or with the track rails according as said relay J is energized or dei nergized, and means controlled by a train entering said section from the end at which source if is located for energizing relays K and J said means being ineffective when a train enters the section from the other end.

11. ltn combination, a section 3-D of railway track, two sources If and if of alternating current located adjacent the ends C and D of said section respectively, means for causing current to flow along the two track rails of the section from the source L when a train enters the section from end D, and means controlled by a train entering the. section from end C for causing current to flow along the two track rails of the section from the source L 12. In combination, a section of railway track, two sources of alternating current located adjacent the ends of saidrsection, and means controlled by a train entering the section from either-end for causing current to flow in the same direction along the two track rails of the section from the source at the opposite end.

13. lln combination, a section (3-1) of railway track, two normally deenergized relays K and J located adjacent the ends C and D of said section respectively, means controlled by a train entering said section from end C for energizing said relays said means being ineffective when a train enters the section from end I), normally det nergized relay K located adjacent end D and arranged to be energized when a train enters the section from end D but not from end t, two sources of alternating current L and l! located adjacent ends C and D of said section respectively, and means controlled by said relays for causing current to flow along the two track rails of said section from source L when relay K is energized and from source L when relays K and J are energized.

'14. In combination, a section (-13 of railway track, a source of alternating cur rent Hf adjacent one end C and normally connected across the track rails, a second sonrce of alternating current L adjacent theend C,

all)

incense a source of alternating current H adjacent end D and normally disconnected from the rails, a second source of alternating current L adjacentend D, means controlled by a train entering said section from end D for causing current from source L to flow along the two track rails of the section in the same direction, and means controlled by a train entering the section from end C for disconnecting source H from the rails and for connecting source H across the rails at end D and for causing current from source L to flow along the two rails of the section in the same direction.

15. lln combination, a section of railway track, a track circuit comprising a source of current and a track relay connected across the rails at the ends of said section respectively, a normally deenergized stick relay adjacent the same end of the section as the track relay, means controlled by a front contact of said stick relay for causing a traffic controlling current to flow along the two rails of said section in the same direction, and means controlled by said track relay for causing said stick relay to be energized when a train enters the section at the end at which the track relay is located and to remain energized until the track rela again closes, said latter means being me ective to energize the stick relay when a train passes through the section in the opposite direction.

16. In combination, a section of railway track, a track circuit comprising a source of current and a track relay connected across the mile at the ends of said section respectively, a normally deenergized stick relay adjacent the same end of the section as the track relay, means controlled by a front contact of said stick relay for causing a trafiic controlling current to flow along the two rails of said section in the same direction, a signal for said section controlled by said track relay, means controlled by said track relay and by said signal and operating when a train enters the section at the end at which the track relay is located to energize said stick relay while the signal still indicates proceed, means for keeping said stick relay energized until the track relay becomes energized, said two last-mentioned means being inefi ective to energize the stick relay when a train passes through the section in the opposite direction.

17. In combination, a section of railway track, a track circuit comprising a source of current and a track relay connected across the rails at the ends of said section respectively, a normally deenergized stick relay adjacent the same end of the section as the track relay, means controlled by a front contact of said stick relay for causing a trafiic controlling current to flow along the two rails of said section in the same direction, a signal for said section controlled by said track relay, a pick-up circuit for said stick relay controlled by a back contact of said track relay and by a contact operated by said signal and closed or open according as the signal indicates proceed or stop, and

a holding circuit for said stick relay controlled by a front contact of the stick relay and by a back contact of the track relay.

18. in combination, a section C-D of railway track, two track relays T and T adjacent the ends of said section, a line relay R adjacent the end C of said section, a stick relay K also adjacent end G and controlled jointly by track relay T and by said line relay, a repeating relay 3 adjacent end D at said section, a line circuit extending through said section and normally including said line relay, and means controlled by said track relays for disconnecting said line relay from said circuit and connecting said repeating relay with-said circuit through a contact of said stick relay.

19. In combination, a section Cw-D of railway track, two track relays T and T adjacent the ends of said section, a line relay R adjacent the end S of said section, a stick relay K also adjacent end C and controlled ointly by track relay T and by said line relay, a repeating relay J adjacent 'end D of said section, a common wire and a line wire extending through said section, one terminal of said line relay and one terminal of said repeating relay being connected with said common wire, a contact operated by track relay T for connecting said line wire with a source of current through a contact of said stick relay or with the remaining terminal of the line relay, a contact operated by track relay T for connecting said line wire with a source of cur rent or with the remaining terminal of said repeating relay, each source of current being also connected with said common wire, and traffic governing means controlled by said repeating relay.

20. lln combination, a section C-D of railway track, two track relays T and T adjacent the ends of said section, a line relay R adjacent the end C of said section, a stick relay K also adjacent end C and controlled jointly by track relay T and by said line relay, a repeating relay J adjacent end D of said section, a line wire and a common wire extending through said section, one terminal of said repeating relay and one terminal of said line relay being connected with said common wire, a source of current L adjacent one end of, said section and a source of current L adjacent the other end of said section one terminal of each of said sources being connected with said common wire a contact operated by track relay T for connecting said line Wire with the remaining terminal of source If through a contact of said stick relay K or with the remaining terminal of the line relay R, a contact operated by track stay '1" for connecting said line wire witn the remaining terminal of said source L or with the remaining terminal of said repeating relay J, and trafiie governing means 10 cont-rolled by said repeating relay.

In testimony whereof I affix my signature in presence of two witnesses.

RUNALD A. MC'JANN Witnesses:

A. HERMAN WneNnR, J. H. S'rnm,

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