US1213161A - Railway signaling system. - Google Patents

Description

A. v. T. DAY RAILWAY SIGNALING SYSTEM.

APPLYICAUONHLED"AUG;22.'I908- 1,213,161. Patented Jan.'23,1917.

2 SHEETS-SH EET I.

miwmea I w I I liivent'or m s Nomns mnms m. rucmn I I 2 a. wldmuc ran. a. c

v. 1;; DAY. RAILWAY SJGNALING SYSTEM.

APPLICATION FILED AUG.22. 1908. 1,213,161. Patented Jan. 23, 1917.

. 2 SHEETS-SHEET 2- It Ztwemem Iwvento? UNITED STATES ATENT OFFICE.

ALBERT v. T. DAY, or NEW ROCHELLE, new YORK, ASSIGNOR, BY MESNE ASSIGN- MENTS, To HALL SWITCH & SIGNAL COMPANY, or NEW YORK, N. Y., A CORPORATION OF MAINE.

RAILWAY SIGNALING SYSTEM.

Specification of Letters Patent.

Patented Jan. 23, 1917.

Application filed August 22, 1908'. Serial No. 449,756.

To all whom it may concern Be it known that I, ALBERT V. T. DAY,

a citizen of the United States, residing at New Rochelle, in the county of lVestchester and State of New York, have invented a certain new and useful Improvement in Railway Signaling Systems, of which the following is a specification, reference being had therein to the accompanying drawings, forming part thereof.

My invention relates to automatic electric traflic-controlling systems for railroads, and relates more particularly to block signal systems adapted for operation inconnection with electric railroads.

In certain block signal systems the operation of the signal-controlling apparatus involves the electrification of taek circuits formed by the rails, or portions thereof.

lVhere the track circuits are constantly energized throughout the system, as has been proposed in such systems, a relatively great waste in energy results, and generating apparatus of relatively great capacity must be provided.

One object of the present invention is to avoid such waste of energy in signal systems or other traliic-controlling systems, by the use of automatic apparatus by which the track circuits are so controlled that they are normally deenergized, and are energized only in those blocks or portions of the line which are within the zone or section occupied by, or adjacent to, a train or trains on the line, so that the track circuits are energized only where and when their operation is involved in the traffic control.

In certain systems employing normally energized track circuits and operating on the normal safety principle, the use of automatic apparatus of the kind above referred to, without other changes in the systems, results in converting them from the normal safety principle to the normal danger principle, and a second object of my invention is to thus convert such systems into normal danger systems by the application of such automatic apparatus.

In railway signaling systems employing track circuits it is common to so connect the sources of signaling current with the track rails that these sources are shortcircuited by the trains or cars as they pass over the line. I

Another object of the present invention 1s to. avoid such short-circuiting, since it is wasteful of energy.

In carrying out my invention, I use apparatus operating automatically, but controlled by or from the trains themselves, for controlling the track circuits, this apparatus operating as thetrain moves through the line to connect the track circuits for a certain distance in advance of the train with the sources of current for energizing them, and to disconnect the track circuits as soon as they have completed their trafliccontrolling functions" and preferably the track circuit of the block or section occupied by the train is disconnected immediately upon the ent 'ance' of the train to the block or section to avoid short-circuiting by the train.

Other objects and features of the invention will be set forth in connection with the description of the illustrated embodiment thereof.

I will now describe the embodiment of my invention illustrated in the accompany ing drawings and will thereafter point out my invention in claims.

Figures 1 and 2 represent contiguous portions of a block signal system embodying my invention, Fig. 1 being the eastern or right-hand portion, and Fig. 2 the western or left-hand continuation of the same.

The drawings illustrate the west-bound track and its signal apparatus of adoubletrack railroad, and include three complete blocks. The east-bound track. and its signal apparatus are omitted, being similar in general construction and principle of operation to those shown; The four illustrated signal stations are designated, respectively, by the letters B, C, D and E, while the eastern or right-hand end of the initial block or section is indicated at A.

The apparatus at all the signal stations except the first is the same, and similar reference numbers are used for corresponding parts, followed, where necessary, by letters to indicate the stations at which thedesignated parts are located.

The invention is shown as used in connection with a signal system disclosed in an application of Clarence 1V. Coleman, Serial Number 421,314,1iled March 16, 1908. The Coleman system is adapted for use in connection with electric railroads in which the track rails are utilized as a part of the cir cuit for transmission of the traction cur rent and in the drawings of the present application the track rails 1 and the third rail or trolley wire '2 are shown connected with an alternating current generator 3 which supplies the traction current. The track rails are divided into blocks or sections by heavy cross-bonds 4 of negligible impedance, so as to serve both as eliicient conductors for the traction current and also as conductors for the inductive track circuits peculiar to the Coleman system. Within the rails, at the ends of the blocks, are located the inductive track coils 5 and 5 by which the signal control is effected.

The automatic track-circuit controlling apparatus is arranged in sets located, except in the initial section, at the middles oi the several track circuits. Five such sets are illustrated, designated from east to west as a, Z), 0, (Z and e.

The inductivetrack coils 5 and 6, when in operation, act to energize track relays 7 and S which control the line circuit at respective ends of a block. These relays are of the polarized alternating-current type, in which a field magnet is alternately polarized in opposite directions by alternating current in the field magnet windin The field magnets of the illustrated relays are energized through feed wires 9 and 11 connected with the secondary terminals of a transformer 12 at each station. The primary windings of the transformers are energized by a transmission line comprising a line wire 14 and the third rail 2, and the transmission line is fed by a generator 15 which generates current of a frequency substantially dili'erent from that of the traction generator 8. so that the apparatus responsive to the signal-operating current will not, under any circumstances, respond to the traction current.

Each relay has a pivoted armature 16 carrying a contact finger 17 or 1.8 and provided with a coil connected in circuit with one of the track coils 5, 6. The currents in the field coils and the armature coils of the re lays, being derived from the same source, have the same frequency and their phase relation is such that the armatures, when properly energized. tend to rotate in the direction to keep the contact fingers in engagement with cooperatingfixed contacts connected in circuit with the line wires which control the signals.

Each track circuit is energized by a transformer, of which the secondary winding 21 is connected with the two rails at the midd'le of the circuit.

The current proceeds from one terminal of the secondary Winding, through the rail connected thereto in opposite directions to the ends of the track circuit, thence through the cross-bonds 4, to the opposite rail, and back to the trans- :tormer. i

The primary winding 22 of each track transformer is energized from the trans mission line already referred to, comprising the wire 14 and the third rail 2.

The operation of the track-circuit transformers controlled by the automatic trackcircuit apparatus, which acts to energize and deenergize the track circuits according to the position of the train.

The traclccircuit controlling apparatus dili ers somewhat in arrangement according to the length of the blocks. In the illus trated system, blocks BC and CD are comparatiyely short blocks, and a single divided track circuit extends throughout each block. In these blocks, therefore, a single complete. set of track-circuit apparatus is used foreach block. Block DE, however, is represented as a block of such length that it is undesirable or impracticable to control it by a single track circuit. This block is there fore divided at the middle by a cross=b0nd similar to the cross-bonds 4, and two in: dependent track circuits are used in the two halves of the block, each of these track cir-. cuits being energized by a separate trans. former. In order that the branches of these circuits at the middle of the block may control the line circuit of the block, inductive track coils 76 and 77 are located at the ends of these branches and connected with the armature coils of relays 78 and 79 similar to the relays 7 and S. The field magnets of these relays are energized by a. transformer 80 ted by the transmission line, and the contact fingers and fixed contacts are ar ranged in the line circuit by connection with the line wire 61.

Since both track circuits in block DE control the same signals. they must be both energized and de'e'nergized at the same time, and as a complete set of automatic trackcircuit controlling apparatus is used at e, the apparatus at (Z is arranged merely as a repeater to coordinate the control of the two track circuits.

The traclr circuit-controlling apparatus at 7), c and 13 comprises, in each set. two relavs, which are arranged to operate both inde pendently and in conjunction with each other. At 7) and c and 0 one relay 23 di rectly controls the primary circuit of the track transformer by means of the contact linger 24, which is connected by a wire 25 with the transmission line wire 14. The con tact finger cooperates with a fixed contac connected with the primary winding 522 of the transformer. Normally this circuit is 'tion-current line.

"open and the track circuit deenergized, but

when the magnet oi 'the relay 23 is energized, the contact finger 24; mores to the right and closes the circuit, thereby energizing the track circuitcontrolled thereby.

The relay 23 of each set is energized through a line circuit extending to the next set in the rear. This line circuit comprises a line wire 26. The current for operating the relays may be obtained from the trac- At Z) and c and e the magnet of the relay 23 is connected by a wire 27 with one of the track rails, and in. this case the current is (lO-l'lVQf from the traction generator 3.

The line circuit of each relay 23 passes also through the magnet ot' the relay 28 next an the rear, and is controlled, in part, by the contact fingers 29 and 31 actuated by this relay 28, and also, in part, by the contact finger 32 of the relay 23 next in the rear.

Each contact finger 32 is actuated by an armature so constructed or controlled that it is less responsive to the magnet of the relay 23 than is the armature controlling the con-. tact finger 2-l. Hence, a stronger current is required to actuate the contact finger 32, and this arrangement is indicated diagrammatically by showing the contact finger 32 as weighted. hen a current of minor strength energizes the relay 23', the contact finger 2% alone closes its circuit, while a current of full strength causes both contact fingers 24 and 32 to close their circuits.

The means through which the relays 23 and 28 are controlled primarily by the train comprise contact members 3% arranged to be engaged by moving contacts carried by the train. These members may be ar 'anged close alongside the third rail, so as to be engaged by the ordinary contact shoes of the train. In any case, the object is to so arrange them that they are temporarily connected electrically with the main portion of the third rail as the train passes. This may be done by arranging for the contact shoe or trolley wheel to engage both the contact member and the third rail simultaneously, but this is unnecessary when two or more contact shoes or trolley wheels are carried by a train and connected together, for in such a case one shoe or wheel may engage the contact member 34 while another shoe or wheel engages the third rail or the trolley wire.

The apparatus is arranged to energize the track circuits in the two blocks next in advance of that occupied by train, so that both the home and the distant signal ahead may be suitably controlled while the block occupied by the train is deenergized, thus westwardly through the system, will now be described. Suppose a train at A starts toward block BC. In order that the signals at B may be cleared to admit the train, it is necessary to energize the track circuits in the blocks BC and CD. The track circuit controlling apparatus will be set into operation for this purpose when the train engages the contact member 34 at the end of the initial section, but in order to afiord plenty of time for the clearing of the signals, it is desirable to start the automatic action before the train reaches B, and for this purpose an auxiliary contact member is pro- \ided some distance in the rear of B. This contact member is connected with the mag net of a neutral relay 71 and thence, through a wire 7 2, with the wire 35 by which the contact member 3% is connected with the apparatus at b. lVhen the train engages the contact member 70, traction current is sent through the relay 71 and through the wires 7 2 and 35 to Z) and the automatic apparatus is thereby operated to energize the track circuits. At the same time, the relay 71 acts upon its contact finger T3 and thereby closes a. stick circuit which passes from the third rail through a wire Tat to the contact finger and its cooperating fixed contact, and thence through the relay magnet. This stick circuit remains closed after the train has passed over the contact member 70 and continues the transmission of current to 6 until the train engages the contact member 34 When this occurs, the relay 71 is short-circuited by the direct connection of the contact member 34 with the third rail, and the relay 71 thereupon releases its contact finger and opens its stick circuit. The action of the auxiliary contact member 70 and the relay T1 is therefore substantially the same as if the contact member 3L were elongated to exend to the position occupied by the contact member 70.

The current from the contact member 7 0 energizes the relay 23 and causes it to actuate its contact fingerQ to close the circuit through the primary windin 22 of the track transformer, and thus the track circuit is energized in the block BC. The relay 23 also actuatcs its contact finger 32, and thereby closes a circuit through the magnet of the relay 28 This circuit passes from the third rail 2 through a wire 36. a resistance coil 37, and the contact finger 32, and thence through a wire 39, to the magnetof the relay 28. From this magnet the current flows, through the line wire 26 and an interposed resistance coil 33,-to the magnet of the relay 23. From this magnet the circuit is continued to the track rails, and the magnet is energized and ance 37,

est

gized. The operatitm does not proceed further, however, for the current which energizes the relay is current of minor strength owing to the tact that it has to pass through the resistance '37". For this reason the contact finger of the relay 23 is not actuated and no current is sent through the relay 2L to energize the apparatus at (Z and e.

. A further effect of the current transmitted through the magnet of the relay "28" is to cause this relay to actuate its contact finger 31, and this operates to close a stick circuit through av wire and thence through the contact linger 31, to the wire 39, and this stick circuit acts, as will be described later, to maintain the current in the line circuit to c after the relay 23" is de'energized.

The contact finger 29 ot' the relay 28* is not actuated to close its circuit at this time. This contact finger is controlled by an armature which is mochaaically connected with the armature which controls the contact finger 2% of the relay 23", and since the latter armature has already been attracted byits relay magnet the contact finger 29 is thereby held in open-circuit position until it is later released by the dei nergization of the relay 2 3 This preponderance of the magnet 23-} ma y be attained by making this magnet stronger than the magnet 28, and by making its air gap shorter than that of the magnet 28 when their armatures are in their present positions, or either of these cxpedients may be employed.

litter the rain has short-circuited and released the stick relay 71 by engagement with the contact member 34 and has thereafter entered the block BC and disengaged the contact member, current ceases to flow through the wire 35 to Z) and the relay 23" is dei nergized. The contact finger 24: is thereby released and the track circuit is thereby at once definergized in the block as the train enters it. At the same time the release of the contact linger opens the circuit through the relay 28" controlled thereby, but this does not aile t the relay 28" since it has already established. a stick circuit, as before, de-

scribed.

Since the train has entered the block BC, it is necessary to energize the track circuits in the block DE, as well as in the block CD which has already been energized, and this is accomplished by an automatic action by which the current from Z) to 0 is raised to full strength, so that the apparatus at 0 operates to send current of minor strength to (Z and c. This action is consequent upon the release of the contact fingers 2i and 29" by the decnergization of the relay 23". The contact finger 29, immediately upon its release, is actuated to close a circuit which passes from the third rail around the resistthrongh the wire 36 to the contact finger 29, and thence through the fixed contacts of the contact fingers 29 and 31' to the contact finger 31, and thence through the magnet of the relay 28 and through the line wire 26 to 0. Since this current is of full strength it causes the relay 23 to be fully energized so as to actuate its contact finger 32, which now closes the circuit through the resistance coil 37, the magnet of the relay 28", the line wire 26, and the relays at (Z and c. This current is of minor strength and as the apparatus at e is substantially the same .in arrangement as the apparatus at b and 0, it acts to energize the track circuits in the western half of the block DE.

The eastern half of the block DE is controlled at the same time by a relay 66, of which the magnet is interposed in the line wire 26. This relay, through its contact finger 6?, controls the circuit including the track rails and the secondary winding 21 of the track transformer at (Z, and thus this transformer is thrown into operation and the eastern half of the block is energized simultaneously with the western half.

lVhen the train reaches the end of the block BC, it operates to restore the apparatus at Z) to normal deenergized condition by short-circuiting the relay 28*. As soon as the train leaves the contact member 3& and entersthe block CD, the relay 23 is deenergized, and the operations of the apparatus are advanced through another block in the same manner as when the relay 23" was deene-rgized, as above described, and thereafter the same series of operations is continued as the train proceeds through the system.

Not only are the track circuits of the block occupied by a train deenergized by the action of the train upon the automatic apparatus so that short-circuiting of the track transformers is normally avoided and waste of current obviated, but the operation of the apparatus is such as toprevent a train in the rear of an occupied block from energizing the track circuit or circuits in that block in the usual manner. This result is secured by the mechanical connection 01? the armatures controlling the contact fingers 24 and 29. When a block is oecupied by a train the condition of the relays and 28 controlling that block is such, in accordance with the series of operations hereinbetore described, that the contact fingers Z l and 29 are under the control of the relay 28, which is energized at the time, with its armature in position of closest approach, while the armature of the relay 23 is in position of greater recession. This relation of the air gaps of the two magnets L3 and 2-8 causes the magnet 28 to preponderate, notwithstanding the magnet 23 Was in preponderance when the armatures Were in their reverse positions. Under such circumstances current transmitted to the relay 23 consequent upon the advance of a train in the rear is ineffective to actuate the contact finger 24, and therefore the transformer circuit cannot I be closed until the train leaves the block and deenergizes the relay 28 so as to release the contact finger 24 and permit it to be actuated by the relay 23.

lVhere a spur or siding enters a block, apparatus may be provided of a character similar to that at a for initiating the operation of the track-circuit controlling apparatus. Such an arrangement is illustrated in Fig. 1. A siding or spur 86 enters the block BC. The third rail 87 of the spur is energized from the same source as the third rail 2, as indicated by a connection 88 between the rails, and a contact member 89 is located near the switch so as to be engaged by a train as it passes from the spur to the main line. The contact member 89 is connected with the magnet of a neutral relay 90 analogous in its operation 'and construction with the relay 71 above described, and from this relay the current flows through a wire 91 to the line wire 26 and the relays at c. The contact finger 92 of the relay 90 operates a stick circuit as in the case of the relay 71, and is released when the train which has entered the main line reaches the end of the block and engages the contact member 34 The function of the resistance coils 33 may now be described. In the operations of the relays above described current of full strength, that is, of strength sufficient to actuate the contact fingers 82, flows sometimes through a circuit embracing the magnet of the relay 23 alone, and at other times through a circuit embracing also the magnet of the relay 28 at the block next in the rear. Since the natural line resistance is relatively slight, this change in the condition of the circuit would greatly modify its resistance and cause a considerable variation in the strength of the full strength current, except for the use of the additional resistance 33. This so increases the line resistance that the resistance of the relay magnets is comparatively slight, so that the proportionate change in the total resistance in the circuit, due to the inclusion of a relay magnet, more or less is negligible or well within convenient limits. This resistance 33 also reduces the strong currents in the third rail sufficiently to permit their use in relay magnets of low resistance.

The automatic track-circuit controlling apparatus hereinbefore described may be used with signal systems otherwise operating upon either of the normal danger or the normal safety principle, the effect, in. the latter case, being, as before pointed out, to convert the system to the normal danger principle owing to the normal denergization of the track circuits. The signal system chosen for purposes of illustration may now be more particularly described.

"he signal-controlling apparatus comprises, in addition to the track relays above referred to, a line relay a3 at each station. This relay is of the same type as the track relays, having an armature it provided with a coil and a contact finger It has in addition, however, a. neutral armature and contact finger 16, which is operated whenever the field is energized, and in the line relay it is the armature coil which is constantly energized by connection with the wires 9 and 11 and the transformer 12, while the field magnet is connected with the line circuit and controls the operation of the relay.

The home signal 17 is controlled by the neutral contact finger 4-6, and the distant signal 18 by the polarized contact finger 45. Both signals have a bias to danger position, but are provided with electric apparatus of any ordinary or suit-able form for moving them to clear position. \Vhen the contact finger 4:6 is raised, current passes from the wire 9 through a wire 51 to the signal at, thence to the fixed contact cooperating with the contact finger a6, and from the latter by a wire 5L9 to the wire 11. A circuitbrealier 53 is mechanically connected with the home signal so that when the latter is clear the circuit-breaker engages a cooperating fixed contact. Under these conditions the distant signal l8 may also be cleared, by the operation of the polarized contact finger l5 the current passing from the wire 9- through the wire 51, the circuit-breaker 53, wire the distantv signal l8, the wire 5%, the contact finger-l5 and the wire 49 to the wire 11. The circuit-breaker 53 does not affect in any way the normal operation of the apparatus, since the distant signal'is never cleared alone, but this circuit-breaker is merely a precautionary device to prevent the clearing of the distant signal in case the home signal, through mechanical causes, fails to clear when its electric operating device is energized.

The selective ope ation of the signals, by which either the home signal alone or both the home signal and the distant signal are cleared, is effected by reversal of polarity in the line circuit, with the consequent action of the line relay. To effect such reversal, two contact fingers 55 and 56 are mechanically controlled by the home signal 47 (except at station B), being raised and lowered therewith. These contact fingers const tute a polechanging switch, and operate 1n a manner to be presently described. I

In a short block such as the block CD, a set of apparatus, such as that at C or D, constitutes the entire signal-controlling apparatus at each end of the block, but in a long block like DE, which is divided in the middle, additional line relays 7S and 79 are interposed in the line circuit, the line wire 61 being connected with fixed contacts controlled by the contact fingers 81 and 82 of these relays, while the contact fingers are connected by a wire 83. The relays 78 and 79 are similar in construction and operation to the track relays 7 and 8, and their fields are energized by a transformer 80 fed by the transmission line. The armature coils of these relays are connected with inductive track coils 7 6 and '77 similar in operation to the track coils 5 and 6. The relays 78 and 7 9 are thus energized by the track circuits, but they operate, in the same manner as the regular trackrelays, to open the line circuit when their track coils are decncrgized by the presence of a train near the middle of the block.

The normal condition of the signal-con trolling apparatus is shown in Fig. 1, the signals being at danger, the line circuits and the track circuits de'energized, and all the relay-controlled contact fingers being in opencircuit position. Suppose, now, that a train occupies block BC and approaches 0. The track circuits in CD and DE are now energized by the automatic apparatus, as above described, and track coils 5, 5 and 6 76, 77 and 6 are energized, causing the corresponding track relays to actuate their contact fingers in case both blocks are clear. The home signal at D is now cleared as follows: Current flows from the wire 9 through the wire 51*, the contact finger 55, and the wire 57 to the line wire 58, and thence to station D. From the line wire the current passes through the wire 59 to the contact finger, now in closed-circuit position, of track relay 7, and thence through the field magnet of the line relay 43 The current returns through the line wire 61 to the contact finger 18 of the track relay 8 which is now in closed-circuit position, and thence by the wire 62 and the contact finger 56 to the wire 11.

The line relay 43 being energized. as above described, the neutral contact finger 46 is raised and the home signal is cleared. The current is of such polarity, owing to the position of the pole-changing switch at E,

that the polarized contact finger 45 is not raised, and distant signal 48 is not cleared. A somewhat similar operation occurs in block CD. Here, however, owing to the reversal of the position of the pole-changing switch at D, resulting from the clearing of the home signal there, the current in the line wire is of such polarity that both contact fingers of the line relay 43 are actuated, and thus both signals are cleared at C. As soon as the train enters the block CD, the track circuits of that block are automatically deenerglzed, as before described, and the signals at C return to danger. At the same time the track circuit of block EF is energized, the home signal at E is cleared, the current in the line wires connecting D and E is thereby reversed in polarity, and the distant signal at D is cleared in additi n to the home signal. These operations are repeated throughout the line as far as it is clear, Suppose, however, asecond train ap proaches C while the first train in bloc]; CD. The track circuit in CD is not energized through the action of the automatic appa ratus for the reason heretofore given, but even in case it should be energized through some accidental action, such, as the sticking of a relay, the signals at G stillcan not clear: Owing to the presence ofthe first trai1i,.oiieor the other branch of this track circuit is short-circuited, and one of the track coils 5 or 6 is deenergized. One of the line relays 7 or 8 isthus deenergized, and the line circuit is interrupted. No current can flow from D to C and both signals at C remain at danger. ,As soonas thefirst train passes from block CD into blocltDE, the line circuit CD is restored, and as the home signal l? remains at danger, the current transmitted is of such polarity that home signal alone at C is cleared, thus admitting the second train to CD with a Cantionary distant signal.

In the absence of the automatic controlling apparatus for the track circuits, the above-described signal system operates as a normal safety system, for all the track circuits, track relays, line circuits and line relays are normally energized and the signals are maintained clear by their electric operating devices.

The present invention is applicable to any signal. system or to a traffic-controlling system of any kind in which track circuits are employed, and it may be arranged to control any required number of blocks in advance of a train.

It is obvious that various modifications may be made in the embodiment of the invention hereinbefore described and illustrated in the accompanying drawings within the nature and scope oil" the invention as defined in the following claims.

Where the term train is used in the claims it is to be understood as coveringany rolling stock, whether a single car or loco.- motive or several members coupled together.

I claim:

1 A traific-controlling system comprising trac'lt circuits. means for energizing them,. and means acting automatically to deenergize the track circuit in the portion of the line occupied by a train.

2. A trailic-controlling system comprising normally-deenergized track clrcuits, and means acting automatically to energize the track i i is successively ahead of a tram moving through the line and to denergize the track circuit at the point occupied by the train.

3. A traffic-controlling system divided into blocks, track circuits each occupying substantially the whole of a block, and means acting automatically to energize a block ahead of a train and to denergize the block occupied by the train.

4. A traificcontro1ling system comprising track circuits, and relays for controlling the track circuits each having two contact fingers responsive to currents of different characters, one contact finger controlling one track circuit and the other contact finger controlling an adjacent track circuit.

5. A traffic-controlling system con'iprising a track having continuously-conductive rails and cross-bonds constituting track circuits,

traffic-controlling devices responsive to currents in the track circuit, and means, normally inactive, for energizing the track circuits, said means operating automatically, under control of a train to energize a tr: c1 circuit in advance of the train without energizing the track circuit occupied by the train.

6. A traliic-controlling system comprising traffic-controlling means, a traiiic-controlling rail circuit in control thereof, and means for deenergizing the rail circuit when a train is present thereon.

In testimony whereof I afiix my signature in presence of two Witnesses.

ALBERT V. T. DAY.

\Vitnesses BERNARD COWEN, \VM. ASHLEY KELLY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

Images