US2082741A - Traffic control system for railroads - Google Patents

Description

.[une 1-; 1937. R. M. PHlNNEY TRAFFIC CONTROL SYSTEM FOR RAILROADS I Original Filed June 26, 1930 A a 0mm LN INVENTOR WATTORNIIEY Patented June 1, 1937 UNITED STATES PATENT OFFICE TRAFFIC CONTROL SYSTEM FOR RAILROADS Application June 26, 1930, Serial No. 463,940 Renewed October 26, 1932 26 Claims.

This invention relates to systems and devices employed in the control of railroad track switches, and more particularly pertains to time element means for use in such systems.

Where a track switch and the signals governing traffic thereover are under the control of an operator, it is necessary to provide means preventing that switch from being operated to a new position, if a governing signal is cleared. l However, it is highly desirable that such cleared signal may be put to stop at any time the operator so desires, so that an on-coming train may be stopped, if possible, to allow the operator to change the route set up. But, if the on-coming l5 train is unable to stop within the approach to the signal that was formerly cleared but which is now at stop, it is dangerous to operate the track switch as soon as such signal has been returned to a stop indication.

Such conditions are adequately provided for if a suitable time period is required between the returning of a governing signal to stop and the time at which the track switch may be operated, as this time period is either sufiicient for the 25 on-coming train to stop Within the approach to the formerly cleared signal, or to pass onto the switch at which time other locking means is actuated by the train to prevent operation of that track switch.

With the above and other considerations in mind, it is proposed in accordance with the pres ent invention to provide means normally causing a lapse of a predetermined time between the returning of a signal to stop and the operation of 35 the track switch associated therewith, this predetermined time being measured by means including a thermal time element device which requires substantially the same length of time for each operation regardless of the interval between successive operations.

It is further proposed to provide simple and safe means for restoring the control of the track switch to the operator immediately after the passage of a train, without the intervening of the usual time period.

Various other features, objects and advantages of the present invention will be in part obvious from the accompanying drawing, and in part pointed out as the description of the invention progresses.

The accompanying drawing illustrates in a simplified and diagrammatic manner one form that the present invention may assume, the parts and circuits being shown more with the object 55 of making it easy to understand the principles and mode of operation of the invention, than with the purpose of illustrating the detailed con struction of the various devices involved and the circuit organization preferably employed in practice.

With reference to the drawing, a stretch of single track comprising rails 5 has been shown having a diverging route or passing siding comprising rails 6 connected thereto through a suitable track switch TS. This track switth TS is indicated as being operated'by a suitable switch machine SM, such for example as shown in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923, the control of said switch machine being accomplished by an operator located at some convenient point, such switch machine control means being indicated by the dotted rectangle SMC connected by a dotted line to the switch machine SM, but it is to be understood that the track switch TS may be operated in any other suitable manner.

The traflic in an east bound direction over the track switch TS is governed by signals l and LA for respectively governing traflic over the main track or the passing siding; similarly, the signals 2 and 2A are provided for respectively governing trains in a west bound direction over the track switch TS from the main track or the passing siding. These signals 'l-|A and 2--2A may be controlled by the operator at a convenient point by any suitable means, such signal control means represented by the dotted rectangle SGC connected by a dotted line to the respective signals. This manual control is preferably interrelated with the usual automatic control governed in accordance with traflic conditions along the right of way in a manner to cause these signals to give stop indications automatically upon the presence of a train in certain portions of the track, all in accordance with the usual practice employed for semi-automatic signals in interlocking plants, or in accordance with remote control systems of the type disclosed in the pending application of S. N. Wight, Ser. No. 120,423, filed July 3, 1926. It is to be understood that these signals may be of the light signal type but have been shown for convenience as being of the semaphore type. Each signal is provided with suitable contacts which are closed only when the corresponding signal is giving a stop indication.

Associated with the track switch TS is the usual detector track section having a battery B and a track relay T controlled in the usual manner. A track instrument TI is provided preceding the track switch to provide a check upon the track mal conditions (as shown) when the train is not present to furnish such actuation. Such a track instrument, however, is preferably of the type which requires the heavy stresses to actuate it that can only be exerted by a train, which protects it from false actuation by a hand car, workman or the like. 1

A lock relay L is provided having a front contact included in the common operating wire of the switch machine SM which is thus prevented from being operated by the operator at such times that this look relay is not energized. Should the track switch TS be operated by some other suitable means than a power operated switch machine, such for example, as a mechanical lever and pipe line, suitable locking means would. be provided to prevent the operation of the switch, this locking means being released only when the lock relay L is energized, it being understood of course that'the locking means shown is merely illustrative of one manner in which the lock relay L prevents manual operation of the track switch from a remote point.

A relay M is provided to indicate when the signals llA and 2-2A are at stop, any one of which signals if cleared will cause the relay M to be deenergized. Also, a stick relay S is provided to register the actuation of a time element relay TE, and to accomplish such other functions as are hereinafter pointed out. These relays L, M and S are conventionally shown as relays having neutral armatures, and may be of any suitable electromagnetic type.

The time element relay TE is of the thermal relay type, such for example, as shown in the application of J. Willi No. 463,963, filed June 26, 1930, entitled Thermal relay. This relay TE includes a bi-metallic element l2 which is actuated by a heating coil i l from its normal extreme position to the opposite extreme position during a predetermined time period when the heating coil is energized with a given current. This bi-metallic element is also preferably provided with compensating means to allow for the variations in the room temperature in which it is located, so that the period of time required for the element 92 to be actuated by a given our rent flowing in the coil i l to an opposite extreme position, and the period of time required for this element 52 to return to its former extreme position after the heating coil it is deenergized, shall each respectively be substantially the same for each operation. A resistance R is provided to allow adjustment of the current value flowing in the energizing circuit of the relay including the heating coil 54. At one end of the heating element i2 is an insulating block G at-- tached thereto, for suitably actuating movable contacts 56 and l! which are adapted to respectively engage fixed contact is or it, when the bi-metallic element i2 is in a normal extreme position or in an energized extreme position.

The relay M is normally energized when the signals l- |A and T-2A are at stop through a circuit from the positive terminal of a suitable source of electrical potential indicated as through contact of signal 2, wire 2|, contact 22 of signal 2A, wire 23, contact 24 of signal IA, wire 25, contact 26 of signal I, wire 27, winding of relay M, to the opposite terminal of the suitable source indicated as Assuming that the signals l-IA and 22A are at stop, and that, either a train has passed to restore the devices to normal conditions, or sufficient time has lapsed to restore the devices to normal positions, the lock relay L is energized from the positive terminal of a suitable source of electrical potential indicated as through fixed contact l8 of thermal relay TE, movable contact l6, wire 30, front contact 3| of stick relay S, wire 32, front contact 33 of track relay T, wire 34, closed contact H of track instrument TI, wire 35, winding of lock relay L, to the opposite terminal of the suitable source indicated as Also; with the circuit arrangement and devices in the conditions as shown, the stick relay S is energized through a circuit from the positive terminal of a suitable source of electrical potential indicated as through wire 38, heating coil i i of thermal relay TE, adjusting resistance R, wire 39, front contact 430 of relay S, wires 4! and 412, winding of relay S, wires 43 and M, front contact 45 of relay M, to the opposite terminal of the suitable srfirce indicated as Although sufhcient current flows in this circuit to maintain the contacts of the stick relay in actuated positions, this current is insuihcient to appreciably heat the thermal ele-' ment of the relay TE.

It is to be understood, that if the thermal element of the relay TE is adjusted to be actuated on such a small value of current that this current in the stick circuit of the relay S becomes objectionable, a front contact may be included in the stick relay S, in a manner to directly provide positive energy to wire 4| when the relay is energized, while back contact 49 will still be employed to control the energization of relay TE as shown.

Let us now assume that the operator clears one of the signals through the signal control means SGC, such for example as signal 2, then the contact 20 is operated to an open position thereby deenergizing the relay M. This deenergization of the relay M opens the stick circuit for the stick relay S at front contact %5 causing its contacts ill and ll] to assume deenergized positions which in turn open the energizing circuit for the lock relay L at front contact 3|. The deenergization of the lock relay L opens the common control 'wire of the switch machine at front contact 50, so that the operator cannot operate the track switch TS through the switch machine control means SMC.

If the operator now decides to return the signal 2 to a stop position and then operate the switch machine to a reverse position, to allow'a train to move off the passing siding, then the contact 28 is closed and the relay M is then energized in response thereto, but the switch machine does not respond to the manual control SMC until the relay L is energized.

The energization of the relay M closes an energizing ci cuit for the heating coil H! of the thermal relay TE" from the positive terminal of the suitable source of electrical potential indicated as through wire 38, heating coil l4,

adjusting resistance R, wire 39, back contact 16 of relay S, wires 4? and 44, front contact 45 of relay M, to the opposite terminal of the suitable source indicated as After a predetermined time the bi-metallic element i2 is actuated to a left hand position to actuate the movable contact ii to engage the fixed contact Hi. This closes a pick-up circuit for the stick relay S from the positive terminal of a suitable source of electrical potential indicated as through movable contact ll, fixed contact 99, wires 48 and d2, winding of relay S, wires 43 and M, front contact 45 of relay M, to the opposite terminal of the suitable source indicated as As soon as the contacts of relay S are actuated to energized positions, the energizing circuit for the heating element of relay TE is opened at back contact Gil of the relay S, while this front contact of relay S closes its stick circuit as heretofore traced. As the current which now flows in the stick circuit is of insufficient value to effect the heating coil i i of relay TE, the bi-metallic element returns to its normal position after a predetermined time.

With the stick relay S now energized and the thermal relay TE in a normal non-actuated position, the energizing circuit for the lock relay L is completed, which permits the response of the switch machine SM to the switch machine control SMC. Thus, the switch TS is prevented from being manually controlled for a predetermined time period after any governing signal is put to stop, this time period including the heating and cooling time of the thermal element 52 of relay TE (required to successively close'its front and back contact).

Let us assume that the operator now controls the track switch TS to a reverse position after which he clears the signal 2A. The relay M is deenergized by the opening of contact 22 and prevents further operation of the switch machine SM except, as heretofore explained, after the signal 2A is returned to normal. But, assuming that while the signal 2A is cleared, a train passes over the track switch TS onto the main track in ac cordance with the signal 2A, the track relay T is deenergized due to the shunting of the detector track circuit, and the track instrument TI is actuated by the presence of the train in a manner to close contact id and to open contact II. Also, with the detector track circuit occupied, the signal 2A is put to stop by automatic means (not shown) thereby closing the circuit for the relay M. As the track relay T is shunted, the circuit for the relay L is opened at front contact 33 of track reiay T; also, as the track instrument is actuated, the contact H of the track instrument TI is open. This double opening of the circuit of the relay L insures that the switch machine cannot be operated by the operator during the presence of a train upon the detector track section.

The presence of the train is also employed to energize the stick relay S without the actuation of the relay TE. This energizing circuit is traced from the positive terminal of a suitable source of electrical potential indicated as (-1-), closed contact iii of track instrument TI, back contact 52 of relay T, wires 53 and 52, winding of relay S, wires 4-3 and d4, front contact 35 of relay M, to the opposite terminal. of the suitable source indicated as The energization of the stick relay S through this pick-up circuit causes the contacts of the relay S to assume energized positions closing its stick circuit as heretofore traced.

As soon as the train moves off the track section closing the front contact 33 of track relay T and the contact H of track instrument TI, the circuit for the relay L will then be completed as heretofore traced allowing the switch machine SM to be immediately operated in response to operation of the manual switch machine control SMC.

From the above description, it is obvious that when the time element relay TE is employed to release the locking means of the switch machine SM, its thermal element is first heated and then cooled in order to determine or measure the time intervening between the putting to stop of a signal and the operation of the switch machine. In other words, the actuation of the time element relay is registered by the stick relay S, which then deenergizesthe time element relay returning it to normal, after which the switch machine SM may be operated. This arrangement provides that the switch machine is not unlocked until the time element relay TB is returned to a normal position in readiness for its next operation thereby insuring that the time period marked off or measured by the thermal time element relay of this invention is always substantially the same regardless of the number or the frequency of its successive operations. This is true as the cooling time period of the thermal element for each operation is included in the time period measured off, which prevents the thermal element from ever being heated an appreciable value above room temperature when in a normal position, thereby providing substantially the samerelative starting point for each operation.

It is also seen from the above description, that should the detector track circuit become accidentally shunted by a track crew or open circuited by the breaking of a bond wire, the locking of the track switch TS will not be falsely released, as the presence of a train is required to actuate the track instrument. Similarly, the converse is true in that the track instrument cannot for some erroneous reason falsely unlock the track switch TS as the shunting of the detector track circuit is required in conjunction therewith. Thus, one specific embodiment of the present invention is shown and described as applied to a railroad track switch, but it is to be understood that the invention is not limited to this particular application or to the particular structure and arrangement of parts and circuits shown and described, but various additions, modifications and adaptations of the specific embodiment of the present invention may be made all in accordance therewith without departing from the scope thereof except as demanded by the scope of the appended claims.

What I claim is:

1. In a traffic controlling system for railroads, a power operated track switch, signals governing traffic over said track switch, a time element device temporarily actuated each time when said signals are put to stop, means registering the temporary actuation of said time element device, and means preventing the operation of said track switch except when said time element device has returned to normal after registering a temporary actuation.

2. In a trafiic controlling system for railroads, a power operated track switch, signals governing trafiic over said track switch, a time element device temporarily actuated each time said signals are put to stop, means registering the temporary actuation of said time element device, means a1- lowing the operation of said track switch only.

when said time element device has returned to normal after registering a temporary actuation, and means cancelling said registering means when said signals are clear.

3. In combination, a power operated track switch, a signal governing traific over said switch, a lock relay acting while deenergized to prevent operation of said switch, a stick relay, a pick-up circuit for said stick relay governed by said signal and traflic conditions adjacent said signal, a stick circuit governed by said signal, a time element device, means actuating said time element device when said stick relay is deenergized and said signal indicates stop, a second pick-up circuit for said stick relay closed when said time element device is actuated, and a circuit energizing said lock relay closed only when said stick relay is energized and said time element device is in its non-actuated condition.

4. In a control system for railroads, a track switch, signals governing traflic over said track switch, locking means normally effective to prevent operation of said track switch for a predetermined time after said signals are caused to indicate stop. a detector track section having a track relay, a track instrument in said detector track section, and means causing said locking means to be ineffective to prevent operation of said track switch if both said track relay and said track instrument indicate the presence of a train.

5. In combination, a track switch, signals governing trafiic over said switch, locking means normally effective to prevent operation of said track switch for a predetermined time after said signals indicate stop, a detector track section having a track relay, a track instrument in said detector track section, means preventing operation of said track switch when either said track relay or said track instrument indicate the presence of a train, and means causing said locking means to be released if said track relay and said track instrument indicate the presence of a train.

6. In a control system for railroads, a track switch, signals governing traffic over said switch, manual control means for said switch and said signals, a detector track section having a track relay, a track instrument physically engaged by a train passing said track switch, and means causing said manual control means to be ineifective to operate said track switch and said signals when said track relay and said track instrument indicate the presence of a train.

- '7. In a control system for railroads, a track switch, signals governing traffic over said switch, manual control means for said switch and said signals, a detector track section having a track relay, a track instrument physically actuated by a train passing said track switch, locking means preventing manual control of said switch for a predetermined time after said signals have been put to stop, automatic means for putting said signals to stop, and automatic means releasing said locking means if said track relay and said track instrument indicate the presence of a train and said signals have been put to stop.

8. In combination, a power operated track switch, a signal governing traffic over said switch, a lock relay acting while deenergized to prevent operation of said switch, a stick relay, a pick-up circuit for said stick relay governed by said signal and traffic conditions adjacent said signal, a stick circuit governed by said signal, a time element device, means actuating said time element device when said stick relay is deenergized and said signal indicates stop, a second pick-up circuit for said stick relay closed when said time element device is actuated, and a circuit energizing said lock relay when said stick relay is energized and said time element device is not in its actuated condition.

9. In combination, a track switch, manually controllable means for governing operation of said track switch, a track circuit associated with said track switch including a track relay, a track instrument having contacts operated by the passage of a train and located in the section of said track circuit, locking means for locking said track switch against operation, and means for releasing said locking means effective upon temporary presence of a train as manifested simultaneously by said track relay and said track instrument.

10. In combination, a track switch, manually controllable means for governing operation of said track switch, a track circuit associated with said track switch including a track relay, a track instrument having contacts operated by the passage of a train associated with said track switch, locking means for locking said track switch against operation, a stick relay, a pick-up circuit for said stick relay closed only if a train is manifested simultaneously by said track relay and said track instrument, and a circuit for rendering said locking means ineifective including in series a front contact of said stick relay and normally closed contacts controlled by said track relay and said track instrument.

11. In combination, a track switch, manually controllable means for governing operation of said track switch, a signal associated with said track switch, a track circuit associated with said track switch including a track relay, a track instrument having contacts operated by the passage of a train associated with said track switch, locking means for locking said track switch against operation, a stick relay, a pick-up circuit for said stick relay closed only if said signal is at stop and a train is manifested simultaneously by said track relay and said track instrument, and a circuit for rendering said locking means ineffective including in series a front contact of said stick relay and normally closed contacts controlled by said track relay and said track instrument.

12. In combination, a track switch, manually controllable means for governing operation of said track switch, a signal associated with said track switch, a track circuit associated with said track switch including a track relay, a track instrument having contacts operated by the passage of a train and associated with said track switch, locking means for locking said track switch against operation, and means for releasing said locking means eifective upon temporary presence of a train as manifested simultaneously by said track relay and said track instrument providing said signal is then at stop.

13. In combination, a section of railway track, a switch associated with said section, a switch lock relay for controlling the operation of said switch, a track circuit in said section including a track relay, a time element relay for controlling the operation of said switch locking relay, manually controlled means for controlling the operation of said time element relay, and a circuit for said locking relay including in series a front contact of said track relay and a track device contact separate from said track circuit and opened only by the presence of a train in said section.

14. In combination, a section of railway track, a track switch in said section, a switch machine for operating said switch, a signal governing the movement of trafiic over said track switch, a stick relay which must be energized to permit control of said switch machine, a track circuit extending the entire length of said section and including a track relay, a track device in said section which by physical actuation by said train manifests the presence of a train in said sec-- tion, a pick-up circuit for said stick relay including in series a back contact of said track relay and a normally open contact of said track device, and a stick circuit for said stick relay closed only if said signal is at stop.

15. In combination, a section of railway track,

a track switch in said section, a switch machine for operating said switch, a signal governing the movement of traffic over said track switch, a stick relay which must be energized to permit control of said switch machine, a track circuit extending the entire length of said section and including a track relay, a track device in said section but separate from said track circuit to manifest the presence of a train in said section, a pick-up circuit for said stick relay including in series a back contact of said track relay and a normally open contact of said track device, a stick circuit for said stick relay closed only if said signal is at stop, another relay having control contacts in the energizing circuit for said switch machine, and an energizing circuit for said another relay including a front contact of said stick relay, a front contact of said track relay and a normally closed contact of said track device.

16. In combination with a section of railway track, a railway switch in said section, a track relay for said section, a signal governing trafiic through said section. a circuit controller associated with said section and normally occupying one position, means independent of said track relay for causing said circuit controller to be operated to another position by a train occupying the section, locking means effective to prevent operation of said switch for a measured time interval after said signal is moved to the stop position, and means requiring said track relay to be deenergized and requiring said circuit controller to occupy said other position for releasing said locking means.

17. In combination, a section of railway track including a track switch, an approach locking relay, a track relay for said section, auxiliary means for detecting the presence of a train in said section, a pick-up circuit for said approach locking relay closed only when the track relay is deenergized and said auxiliary means indicates the presence of a train in said section, and a control circuit for the switch closed only when the approach locking relay and the track relay are energized, and said auxiliary means indicates that no train is present in said section, and manually controllable means rendered effective to operate the switch only when said control circuit is closed.

18. In combination, a section of railway track including a track switch, an approach locking relay, a track relay for said section, auxiliary means for detecting the presence of a train at a particular point adjacent said switch, a pick-up circuit for said approach locking relay closed only when the track relay is deenergized and said auxiliary means indicates the presence of a train at said point, and a control circuit for the switch closed only when the approach locking relay and the track relay are energized and said auxiliary means indicates that no train is present at said point, and manually controllable means effective to operate the switch only when said control circuit is closed.

19. In combination, a section of railway track including a track switch, an approach locking stick relay, means for preventing operation of said switch unless said relay is energized, a signal for governing the movement of traffic over the switch, a track circuit including a track relay connected across the rails of said section, auxiliary means independent of said track circuit for detecting the presence of a train in said section, a pick-up circuit for said approach locking relay closed only when the signal indicates stop, the track relay is deenergized and. said auxiliary means indicates the presence of a train in said section, and a stick circuit for said approach looking relay including a front contact of said relay and closed only when the signal indicates stop.

20. In combination, a section of railway track, traiiic governing means located in said section, a track relay for said section, a circuit controller located in the trackway adjacent said traiiic governing means, means independent of said track relay for causing said circuit controller to occupy one position under normal conditions but to occupy another position when a train occupies said section, a manually controlled relay, circuits including contacts of said manually controlled relay for controlling the operation of said traffic governing means, and a circuit for said manually controlled relay including a front contact of said track relay and a contact of said circuit controller closed only in said one position.

2.1. In combination, a section of railway track, a track switch in said section, a track relay for said section, a circuit controller associated with said section and normally occupying one position, means independent of said track relay for causing said circuit controller to be operated to another position by a train occupying the section, a switch locking relay for governing the operation of said switch, a circuit for said switch locking relay including a back contact of said track relay and a contact of said circuit controller closed only in said other position, and a manually controlled time element relay for controlling said switch locking relay.

22.. In combination, a section of railway track including a track switch, an approach locking relay, a track circuit including a track relay connected across the rails of said section, auxiliary means independent of said track circuit including a normally open contact closed only when a train enters said section and a normally closed contact opened only when a train enters said section, a pick-up circuit for said approach locking relay including in series said normally open contact and a back contact of said track relay, and a control circuit for said switch including in series said normally closed contact and front contacts of said track relay and of said approach locking relay.

23. In combination with a section of railway track including a track switch, a track relay for said section, a circuit controller associated with said section and normally occupying one position, means independent of said track relay for causing said circuit controller to be operated to another position by a train occupying said section, locking means and operating means for said switch, means requiring said track relay to be deenergized and requiring said circuit controller to occupy said other position for releasing said locking means, and means requiring said track relay to be energized and requiring said circuit controller to occupy said one position for rendering said operating means responsive to the release of said locking means.

24. In combination, a section of railway track including a track switch, a signal for governing the movement of traffic into said section, approach locking means effective to prevent operation of the switch for a measured time interval after said signal is moved to the stop position, a track circuit including a track relay deenergized when a train is present in said section, auxiliary means independent of said track circuit for detecting the presence of a train adjacent said switch, means for releasing said locking effective only when said track relay and said auxiliary means indicate the presence of a train in said section adjacent said switch, and manually controllable means for operating the switch effective when said locking is released provided the track relay and said auxiliary means indicate that said train is no longer present in said section nor adjacent said switch.

25. In combination, a section of railway track including a track switch, an approach locking stick relay, means for preventing operation of said switch unless said relay is energized, a signal for governing the movement of traffic over the switch, a track circuit including a track relay connected across the rails of said section, auxiliary means independent of said track circuit for detecting the presence of a train in said section, a pick-up circuit for said approach locking relay closed only when the signal indicates stop, the track relay is deenergized and said auxiliary means indicates the presence of a train in said section, a second pick-up circuit for said approach locking relay including a contact closed momentarily when the signal has been in the stop position for a predetermined time interval provided said approach locking relay is then deenergized, and a stick circuit for said approach locking relay including a front contact of said relay and closed only when the signal indicates stop.

26. In combination, a section of railway track including a track switch, an approach locking stick relay, a signal for governing the movement of trafiic over said switch, a track circuit including a track relay connected across the rails of said section, means independent of said track circuit including a normally open contact closed only when a train enters said section and a normally closed contact opened only when a train enters said section, a pick-up circuit for the approach locking relay closed only when said normally open contact is closed and said track relay is deenergized, a stick circuit for the approach locking relay including its own front contact and a contact closed only when said signal is in its most restrictive condition, and a control circuit for said switch including in series said normally closed contact and front contacts of said track relay and said approach locking relay.

ROBERT M. PHINN'EY.

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