US2178287A - Railway track circuit apparatus - Google Patents

Description

Oct. 31, 1939.

c R. PFLASTERER 2,178,287

RAILWAY TRACK CIRCUIT APPARATUS Original Filed April 28, 1957 INVENTOR A George 18. lastepen BY i HIS ATTORNEY Patented Oct. 31, 1939 srs PAT

RAILWAY. TRACK CIRCUIT-APPARATUS Application April 28, 1937, Serial No. 139,521 Renewed September 7, 1-938 1'7 Claims.

My invention relates to railway track circuit apparatus, and has for an object the provision,

, in a track circuit including a track relay, of

means responsive to the application or removal of a track circuit shunt to compensate for changes in ballast resistance by automatically varying the value of the resistance between the source of track circuit energy and the track rails, in accordance with changes in ballast leakage current so that the current received by the track relay will be maintained substantially constant under wet and dry ballast conditions.

Since the compensating means will function upon an increase in the flow of current from one rail to the other due to a train shunt as well as upon an increase in such current due to a decrease in ballast resistance, another object of my invention is to provide apparatus,

' responsive only to the rapid application or reof its dry weather value when the track circuit is occupied- I shall describe four forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

-The railway track circuit apparatus embodying my invention is somewhat similar to that set forth in the copending application of Paul P. Sosinski, Serial No. 739,946, filed on August 15, 1934, for Railway track circuit apparatus, and the said copending application contains claims which cover broadly certain features of the invention described in my present application.

In the accompanying drawing, Fig. l is a diagrammatic view showing one form of apparatus embodying my invention. Figs. 2, 3, and 4 are diagrammatic views each showing a different modification of a portion-of the apparatus shown in Fig. l and each also embodying my invention.

Similar reference characters refer to similar parts in each of the views.

Referring first to Fig. l, the reference characters. l and 2 designate the-track rails of a stretch. of railway track'which are formed by insulated joints 3 into a track section 5-6. The track section b t is provided with'a track circuit which includes a track relay TR connected across the rails at one end of the section, and a source of energy, here shown as a track battery B, at the other end of the section. One terminal of battery B is connected to one rail of the sectionby a variable resistor I, and the a other terminal is connected to the other rail in series with a relay A andprimary winding 8 of atransformer T. Thereference character S designates a polarized relay comprising a U- shaped core 9 which is either a permanent magnet or is magnetized by means exterior to the core. Pivotally mounted at It in the backstrap of the core 9 is an armature l l which is arranged to oscillate between the two pole faces of the core, and which carries a winding 12 which receives energy from secondary'winding l3 of the transformer T. The armature N that contact l4l5 is closed when the armature H is swung to the right, which I shall term its normal position, and'contact lil5 is opened when this armature is swung to the left or reverse position. as a .last position" relay, that is, armature H,

when deenergized, remains in the position to" which it was last operated until energized again in the opposite direction.

Variable-resistor l is so adjusted that the current supplied to the rails by battery'B in dry relay A will cause this relay to become picked up to close an auxiliary circuit, in multiple with resistor l, to decrease the total resistance between battery B and the track rails so that track relay TR will receive substantially the same amount of energy it received under dry weather conditions. The auxiliary circuit is easily traced and includes front contact I6 of relay A, contact I 4-5 of relay S, and variable resistor l1. When the ballast dries out, the resulting increase in ballast resistance will decrease the current through the winding of relay A to permit the relay to return to its initial condition so that the resistance between battery B and the track rails will be decreased to restore the track circuit current to its dry weather value. Such changes in the value of the current flowing in primary. 8 of transformer T will be gradual in nature and will not, therefore, induce sulficient energy in secondary winding l3 to operate relay S. 7

It will be apparent that since relay A becomes picked up upon an increase in the value of the current supplied to the track circuit due to a cooperates with a pair of contacts l4 and E5 in such a manner The relay S is what is known decrease in ballast resistance, this relay will also become picked up when the section 5-6 becomes occupied by a train due to the shunting action of the wheels and axles of such train. The rapid increase in current, however, due to the train shunt, through primary winding 8 of transformer T will induce an impulse of reverse polarity in secondary winding l3 of transformer T so that armature ll of relay S will be caused to move to its reverse position to open contact I ll5. The opening of contact I l-45 breaks the previously traced auxiliary circuit so that the resistance between the battery B and the track rails can not be reduced when the section 5-6 is occupied. Consequently, the release of the track relay TR will be more positive because this relay need be supplied with only sufficientenergy to maintain the track relay picked up during dry weather conditions, and additional energy can not be supplied to the track relay when the track circuit becomes occupied by a train.

When the train vacates section 5B, the sudden decrease in current flowing in primary winding 8 of transformer T will induce an impulse of normal polarity in secondary winding I3 of transformer T so that armature II will be caused to move to its normal position, thus restoring relay S to its initial condition.

Referring next to Fig. 2, the relay A is connected across the track rails in multiple with the battery B and is, therefore, normally energized. The release value of relay A is so chosen that upon a given increase in the current supplied to the track circuit by battery B the resulting drop in potential across relay A will cause this relay to become released to establish an auxiliary circuit in multiple with resistor 1 so that the total resistance between battery B and the track rails will be reduced. When the inter-rail current returns to its normal value relay A will, of course, become picked up to open the auxiliary circuit. This auxiliary circuit includes back contact 18 of relay A, contact |4--l 5 of relay S and resistor H. The entrance and departure of a train from section 5--6 will operate the relay S to govern the auxiliary circuit in a manner similar to that described for the apparatus shown in Fig. 1.

Referring next to Fig. 3, the reference character Bl designates an auxiliary track battery which supplies a portion of the track circuit current through variable resistor l9 and relay A. Upon a given decrease in the ballast resistance, the relay A will become picked up by the increased current flowing to the track circuit from battery Bl so that front contact iii of relay A will become closed to establish the auxiliary circuit in multiple with resistor I. In this view, however, contact l4--l5 of relay S is included in the circuit for relay A rather than in the auxiliary circuit. Otherwise the apparatus shown in Fig. 3 operates in a manner substantially similar to that for the apparatus shown in Fig. 1.

Referring now to Fig. 4, auxiliary battery Bl is connected by variable resistor 19 and relay A in multiple with battery B and resistor I. In this view the auxiliary circuit is similar to that shown in Fig. 1, and includes contact 14-45 of relay S and contact it of relay A, It is believed that detailed explanation of the apparatus in Fig. 4 is unnecessary because this will be apparent from an examination of the circuits.

From the foregoing description of the apparatus embodying my invention, it will be seen that the shunting sensitivity of the track circuit for the section 56 is increased because the track relay TR need not be excessively overenergized during dry weather conditions to provide the energy necessary to maintain the track relay efiectively energized in. wet weather. Furthermore, I have provided apparatus for automatically preventing any decrease in the resistance between the track battery and the track rails when the section becomes occupied by a train so that the track relay TR can never receive energy in excess of the normal dry weather value with the track section occupied.

Although I have herein shown and described only four forms of apparatus 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 having a pair of track rails, a track circuit for said section including a track relay located adjacent one end of said section and receiving current from said track rails, the track circuit including a source of energy located adjacent the other end of the section for supplying current to said track rails, this source having one of its terminals connected to one of said track rails and having its other terminal connected to the other of said track rails in series with a resistor, an auxiliary relay energized from said source and occupying one or another control position as determined by the amount of current flowing in said resistor due to the ballast resistance between the track rails, and another auxiliary relay also energized from said source and responsive to changes in the value of the current flowing in said track circuit, said other auxiliary relay having a contact which is operative only in response to a rapid change in the value of such current, said auxiliary relays jointly controlling a circuit eiTective when the section is unoccupied and the ballast resistance is below a predetermined value for connecting said other terminal of said source to said other track rail, said circuit including said contact and shunting said resistor.

2. In combination, a section of railway track having a pair of track rails, a track circuit for said section including a track relay located adjacent one end of said section and receiving current from said track rails, the track circuit including a source of energy located adjacent the other end of the section for supplying current to said track rails, this source having one of its terminals connected to one of said track rails and having its other terminal connectedto the other of said track rails in series with a resistor, an auxiliary relay energized from said source and occupying one or another control position as determined by the amount of current flowing in said resistor clue to the ballast resistance between the track rails, another auxiliary relay also energized from said source and responsive to changes in the value of the current flowing in said track circuit, said other auxiliary relay having a contact which is operative only in response to a rapid change in the value of such current, and a circuit effective when the section is unoccupied and the ballast resistance is below a predetermined value for connecting said other terminal of said source to said other track rail, said circuit shunting said resistor and including contacts of both of said auxiliary relays.

3. In combination, a section of railway track having a pair of track rails, a track circuit ior having a pair oi track rails, a track circuit for said section including a track-'relay located adjacent' one end ofsaid section and receiving current fromsaid track" rails, the track circuit ineluding a sou-roe of energy located adjacent the other endof the section for supplying current to said track rails, this source having one of its terminals connected to one of said track rails and having its other terminal connected to the other of said track rails in series with a resistor, an auxiliary relay energized from said source and occupying one or another control position as determined by the amount of current flowing in said resistor due to the ballast resistance between the track rails, another auxiliary relay also energized from said source and responsive to changes in the value of the current flowing in said track circuit, said other auxiliary relay having a contact which is operative only in response to a rapid change in the value of such current, and a circuit effective when the section is unoccupied and the ballast resistance is below apredetermined value for shunting said resistor and by which said other terminal of said source may be connected to said other track rail. said circuit including contacts of both of said auxiliary relays and having a resistor included in series therewith.

4. In combination, a section of railway track having a pair of track rails, a track circuit for said section including a track relay located adjacent one end of said section and receiving current from said track rails, the track circuit including a source of energy located adjacent the other end-of the section for supplying current to said track rails, this source having one of its terminals connected to one of said track rails and having its other terminal connected to the other of said track rails in series with a resistor, an auxiliary relay energized from said source and occupying one or another control position as determined by the amount of current flowing in said resistor due to the ballast resistance between the track rails, and another auxiliary relay also energized from said source and responsive to changes inthe value of the current flowing in said track circuit, said other auxiliary relay having a contact which is operative only in response to a rapid change in the value of such current, said auxiliary relays jointly controlling a circuit for connecting said other terminal of said source to said other track rail, said circuit shunting said resistor and including said contact and a resistor.-

5. In combination, a section of railway track said section including a track relay located'adjacent one end of said section and receiving current from said track rails, the track circuit inoi said track railaa resistor included in serieswith the connection between said other terminal of said source and said other one of said track rails, an auxiliary relay having its winding con- 1 nected in series with the connection between one terminal of said source and one of said track rails, said relay having a contact which is open when the current flowing in the relay winding is less than a predetermined Value, said relay contact being closed when the current flowing in the relay winding exceeds said predetermined value, another auxili'ary relay responsive to changes in the value of the current flowing in said track circuit, said relay having a contact which is operative only in response to a rapid change in the value of such current, and a circuit shunting said resistor and by which said other terminal of said source may be connected to said other track rail, said circuit including contacts of both of said auxiliary relays.

6. In combination, a section of railway track having a pairof track rails, a track circuit for said section'- including a track relay located adjacent one end of said section and receiving current from said track rails, the track circuit including a source of energy located adjacent the other end of said section for supplying current to said track rails, said source having one of its terminals connectedto one of said track rails and having its other terminal connected to the other of said track rails, a resistor included in series with the connection between said other terminal of said source and said other one of said track rails, an auxiliary relay having its winding connected in series with the connection between one terminal of said source and one of said track rails, said relay having a contact which is open when the current flowing in the relay winding is less than: a predetermined value, said relay contact being closed when the current flowing in the relay winding exceeds said predetermined value, another auxiliary relay responsive to changes in the value of the current flowing in said track circuit, said relay having a contact which is op-- era-tive only in response to a rapid change in the value of such current, and acircuit shunting said resistor and by which said other terminal of said source may be connected to said other track rail, said circuit including contacts ofboth of said auxiliary relays and having a resistor connected in series therewith.

'7. In combination, a section of railway track having a pair of track rails, a track circuit for said section including a track relay located adjacent one end of saidsection and receiving current from said track rails, the track circuit including a source of energy located adjacent the other end of said section for supplying current to said track rails, said source having one of its terminals connected to one of said track rails and having its other terminal connected to the other of said track rails, a resistor included in series with the connection between said other terminal of said source and said other one of said track rails, an auxiliary relay having a winding, one terminal of said winding being connected to said one terminal of said source, the other terminal of said winding being connected to said other terminal of said source in series with said resistor, said relay having a contact which is open when and only when the current flowing in the relay winding exceeds a predetermined value, another I auxiliary relay responsive to changes in the value of the current flowing in said track circuit, said relay having a contact which is operative only in response to a rapid change in the value of such current, and a circuit shunting said resistor and by which said other terminal of said source may be connected to said other track rail, said circuit including contacts of both cfsaid auxiliary relays.

In combination, a section of railway track having a pair of track rails, a track circuit for said section including a track relay located adjacent one end of said section and receiving current from said track rails, the track circuit ineluding a source of energy located adjacent the other end of said section for supplying current to said track rails, said source having one of its terminals connecwd to one of said track rails and having its other terminal connected to the other of said track rails, a resistor included in series with the connection between said other terminal of said source and said other one of said track rails, an auxiliary relay having a winding, one terminal of said winding being connected to said one terminal of said source, the other terminal of said winding being connected to said other terminal of said source in series with said resistor, said relay having a contact which is open when and only when the current flowing in the relay winding exceeds a predetermined value, another auxiliary relay responsive to changes in the value of the current flowing in said track circuit, said relay having a contact which is operative only in response to a rapid change in the value of such current, and a circuit shunting said resistor and by which said other terminal of said source may be connected to said other track rail, said circuit including contacts of both of said auxiliary relays and having a resistor connected in series therewith.

9. In combination, a section of railway track having a pair of track rails, a track circuit for said section including a track relay located adjacent one end of said section and receiving current from said track rails, the track circuit including a source of energy located adjacent the other end of said section for supplying current to said track rails, said source having one of its terminals connected to one of said track rails and having its other terminal connected to the other of said track rails, a resistor included in series with the connection between said other terminal of said source and said other one of said track rails, an auxiliary relay having a winding, one terminal of said winding being connected to said one terminal of said source, the other terminal of said winding being connected to said other terminal of said source in series with said resistor, said relay having a contact which is open when and only when the current flowing in the relay winding exceeds a predetermined value, another auxiliary relay responsive to changes in the value of the current flowing in said track circuit, said relay having a contact which is operative only in response to a rapid change in the value of such current, and a circuit shunting said resistor and by which said other terminal of said source may be connected to said other track rail, said circuit being jointly controlled by both of said auxiliary relays and having a resistor included therein.,

10. In combination with a section of railway track, a track circuit comprising a track relay and a source of current therefor both connected with the rails of said section, a current-limiting device included in the connection of said source with a rail of the section, an auxiliary relay energized by current which varies in accordance with the magnitude of the ballast resistance between the rails of said section, another auxiliary relay energized from said source and responsive only to a rapid change in the value of the current flowing in said track circuit, and a shunt path in multiple with said current-limiting device including a contact of each of said auxiliary relays and effective upon a predetermined decrease in said ballast resistance for increasing the current supplied to the track circuit from said source to thereby compensate for said decrease in the ballast resistance of said section.

11. In combination with a section of railway track, a track circuit comprising a track relay and a source of current therefor both connected with the rails of said section, a current-limiting device included in the connection of said source with a rail of the section, an auxiliary relay having its operating winding connected in series with said source and said current-limiting device, another auxiliary relay energized from said source and responsive only to a rapid change in the value of the current flowing in said track circuit, and means controlled by both said auxiliary relays and efiective upon a predetermined decrease in the ballast resistance for decreasing the efiective value of said current-limiting device to thereby increase the current supplied to the track circuit from said source so as to compensate for said deer-ease in ballast resistance of said section.

12. In combination with a section of railway track, a track circuit comprising a track relay and a source of current therefor both connected with the rails of said section, a current-limiting device included in the connection of said source with a rail of the section, a first auxiliary relay energized from said source and picked up or released according as the drop across said currentlimiting device is relatively low or relatively high respectively as determined by the ballast resistance between the rails of said section, a second auxiliary relay also energized from said source and responsive only to a rapid change in the value of the current flowing in said track circuit, and a shunt path in multiple with said current-limiting device including a contact of said second auxiliary relay and a back contact of said first auxiliary relay, said shunt path being effective upon a predetermined decrease in said ballast resistance, for increasing the current supplied to the track circuit from said source to thereby compensate for said decrease in the ballast resistance of said section.

13. In combination with a section of railway track, a track circuit comprising a track relay and a main source of current therefor both connected with the rails of said section, a current-limiting device included in the connection of said source with a rail of the section, an auxiliary source of energy, means including the operating winding of an auxiliary relay for connecting said auxiliary source in multiple with said main source whereby said auxiliary relay will become operated by current from said auxiliary source when the ballast resistance between the rails of said section has a relatively low value, another auxiliary relay energized from said main source and responsive only to a rapid change in the value of the current flowing in said track circuit, and means governed by said two auxiliary relays eflective when said ballast resistance has a relatively low value for closing a shunt path in multiple with said current-limiting device to thereby increase the current supplied to the track circuit from said main source in order to compensate for the decrease in the ballast resistance of said section.

14. In combination with a section of railway track, a track circuit comprising a track relay and a source of current therefor both connected with the rails of said section, a current-limiting device included in the connection of said source with a rail of the section, a transformer connected in series with said source and said currentlimiting device, an auxiliary relay energized from said source and occupying one or another control position. as determined by the amount of current vflowing in said current-limiting device due to the ballast resistance between the rails of said section, another auxiliary relay energized from said transformer and responsive only to a rapid change in the value of the current flowing in said track circuit by way of said transformer, and a shunt path in multiple with said currentlimiting' device including a contact of each of said auxiliary relays and effective upon {a predetermined decrease in the ballast resistance for increasing the current supplied to the track circuit from said source to thereby compensate for said decrease in the ballast resistance of said section. I

15. In combination with a section of railway track, a track circuit comprising a track relay and a main sourceof current therefor both connected with the rails of said section, a current limiting device included in the connection of said source with a rail of the section, a first auxiliary relay energized'from said main source and responsive only to a rapid change in the value of the current flowing in said track circuit, an auxiliary source of energy, means including the operating winding of a second auxiliary relay and a contact of said first auxiliary relay for connecting said auxiliary source in multiple with said main source whereby said auxiliary relay will become operated by current from said auxiliary source when the ballast resistance between the rails of said section has a relatively low value, and a shunt path in multiple with said current-limiting device including a contact of said second auxiliary relay and efiective when said ballast resistance has a relatively low value for increasing the current supplied to the track circuit from I said main source to thereby compensate for the I decrease in the ballast resistance of. said section.

16. In combination with a section of railway track, a source of current connected withthe rails of said section, a current-limiting device included in the connection between said source andone rail of said section, a track relay receiving energy from the rails of the section, means connected with the rails of I said section and responsive to the rateof change of the current supplied to the rails from said source, other means also connected with the rails of said section and energized by current which varies in accordance with the magnitude of the ballast resistance between said rails, and means controlled by both said aforementioned meansefiective upon a predetermined decrease in said ballast resistance for decreasing the effective value of said current-limiting device to thereby increase the current supplied to the rails from said sourceso as to compensate for said decrease in the ballast resistance of said section.

1'7. In combination. with a section of railway track, a track circuit comprising a track relay ballast resistance between the rails of said section has a relatively low value, another auxiliary relay energized from said main source and responsive only to a rapid change in the value of the current flowing in said track circuit, and a shunt path in multiple with said current-limiting device including a contact of each of said auxiliary relays and eflective when said ballast resistance has a relatively low valuefor increasing the current supplied to the track circuit from said main source to thereby compensate for the decrease in the ballast resistance of saidsection.

GEORGE RQPFLAS'IERERQ

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