US2025265A - Railway traffic controlling apparatus - Google Patents

Description

1396- 1935- Hv G. BLOSSER ET AL I RAILWAY TRAFFIC CONTROLLING APPARATUS Filed June 3, 1935' n J a WWW m mm n m w A Patented Dec. 24, 1935 UNl'l'EQ T'i'h'd RAILWAY TRAFIFEC CONTROLLING APPARATUS Herman G. Blosser, Pittsburgh, and Charles W.

Failor, Forest Hills, Pa, assignors to The Union Switch & Signal (Jcmpany, Swissvale, Pa, a corporation cf Pennsylvania Application June 3, 1933, Serial No. 674,200

14 Claims.

Our invention relates to railway traffic controlling apparatus, and more specifically to apparatus for clearing out highway crossing cut sections, operating detector locking track circuits, as well as for clearing out detector track sections generally, in signaling systems employing coded track circuit current for the control of wayside and cab signals.

One feature of our invention is the provision of apparatus of the above character which will not cause improper operation of cab or wayside signals. Another feature is the provision of complete broken down insulated rail joint protection, without requiring numerous control relays and using a minimum number of control line wires per track circuit.

We will describe one form of track circuit clearing apparatus embodying our invention, and will then point out the novel features thereof in claims.

The acco; panying drawing is a diagrammatic view of a stretch of railway track with the associated apparatus embodying our invention as applied to the clearing out of highway crossing cut sections upon the passage of a train.

Referring to the drawing, the block section lL-G, in which trafiic normally moves from left to right in the direction of the arrow, is divided into out sections DE, E-F, and F-G for the purpose of controlling highway crossing signals KS and KS at locations E and )3. Each of the above sections is provided with a track transformer T and a code-following track relay TR. Adjacent track circuits have staggered instantaneous polarities, and the track relays are of the two-element type having a local winding l and a CDntTOl winding 2 so that reverse torque, tending to open the front contacts of these relays, will be developed should. a breakdown of the. insulated rail joints occur.

For simplicity, the continuously operating code filters CT and GT at locations D and G, ectlvely, are shown as supplying track circurrent of but two code frequencies, namely, current of 180 interruptions per nunute over the odically closed contact It'll], and current of w. nterruptions per minute over the periodically closed Contact for the control of wayside and cab signals. In practice, additional code frequencies, selected in accordance with traffic conditic-ns in advance, will normally be used to pro- ,ontrol for multiple aspect wayside and cab a. One form of code transmitter, and one anangement of apparatus for selecting the code to be applied to a track section in accordance with trafiic conditions in advance, are shown and described in Letters Patent of the United States No. 1,773,472, granted to P. N. Bossart on August 19, 1930, and so these parts of the system are illustrated diagrammatically in the present case 5 to simplify the disclosure.

When current of 180 code frequency flows in the rails of section DE which is assumed to be unoccupied, relay TR will operate in step with the code impulses, and the periodic closing of contacts 3- 3 and 3--5 of this relay will cause direct current to be supplied alternately to one and then to the other half of the primary winding of decoding transformer DT, to induce an alternating voltage in the secondary Winding.

he circuit of the secondary Winding of transformer T is tuned to the I83 code frequency by reactor X and condenser C so that the slow releasing decoding relay DR, which is energized from the tuned circuit through a rectifier R will remain picked up as long as section D-E is supplied with rail current of 180 code frequency. In a similar manner, the untuned decoding relay DB which is energized through rectifier R will remain picked up as long as section D--E is supplied with rail current of either 180 or 80 code frequency. If the code frequency is 180, front contacts 6-l and 3fl-3l of relays DR and DB will be closed, thereby causing lamp G of signal S to become energized. Signal S will therefore indicate proceed. When the code requency is 80, relay DR, will be released, and relay DR will be energized, so that lamp Y of signal S will be lighted over contacts 6-8 and 30-3l of relays DR and DB Upon shunting of relay TR by a train, or prolonged interruption of the rail current, relay DR will release due to the collapse of the secondary voltage in transformer DT, so that back contact 3G32 will close the circuit for lamp R. of signal S, to provide a stop indication for following trafiic.

Assuming again that section D-E is unoccupied and that relay TR is following 180 code, contact 53-46 of relay IE will close periodically, maintaining slow releasing relay K energized, and contact 9ll will also close periodically to maintain the slow releasing relay L energized over front contact l2 of relay K Relay L controls the energization of crossing signals X8 and as long as relay L is energized, these signals will remain inoperative by virtue of the open back contact H3. The relays K and L can be conveniently termed decoding relays because, as will appear from the description which follows, 55

these relays respond to code operation of the track relay TR We shall now explain the operation of the apparatus during the passage of a train from location D, through the various cut sections.

When the train enters section D-E, the operation of relay TR will cease, opening contact 9-l0 .to release relay K which in turn will release relay L thus initiating operation of the crossing signals X5 at location E. When the train enters section E-F, relay TR, will release, releasing in turn relays K3 and L which are controlled in the same manner as relays K and L associated with section D-E. The release of relay K will cause relay XR to release, due to the opening of front contact 14, thereby starting the'operation of the crossing signals X5 over 'back contact 16 of relay XR. The release of relay L closing back contact I1, will result in energization of the auxiliary code transmitter ACT which is provided for the purpose of supplied to transformer T plying a clearing or detectioncode to track section DE to clear out this section following the passage of the train into section E-F. This detection code must be of such character as not to cause response of the wayside signal S or of cab signals on a following locomotive which may have overrun location D, and, at the same time, this code must cause operation of relay TR in such manner that both relays K and L will be- I come picked up to stop the operation of the crossing signals X8 One type of detection code which will accomplish the above results consists of a relatively short on period, followed by a relatively long ofi period, these periods being repeated successively. This type of code is employed in the apparatus which we have illustrated, and is supover the periodically operated contact l8 of transmitter ACT wire l9, and back contact 28 of relay L The trans mitter illustrated diagrammatically at ACT may comprise, for example, a motor element which, when energized, causes rotation of the contactoperating cam to produce the short on and long off intervals of the code. Relay TR will pick up during each on interval of the detection code, thus causing pick up of relay K which is suinciently slow releasing to bridge the oif code intervals, during which relay L will receive energy over contact 9-H of relay TR and contact I2 'of relay K Relay L is sufficiently slow releasing to bridge the on code intervals, during which contact 9-H remains open. It will be apparent, therefore, that the detection code will beeifective to stop the operation of crossing signals KS when no train is occupying section D'E. At the safe time, if the periodic frequency of the detection code is sufficiently far removed from the code frequency of the train governing code used for controlling cab and wayside signals,

relays. If desired, a detection or if a suitable time ratio is established between the duration of the on and off detectioncode periods, there will be no response of wayside or locomotive decoding relays such as DR or DB 'That is, the selection of a detection code frequency appreciably far removed from the train governing code frequency, or the suitable choice of the on and 01f time ratio will prevent the energization of decoding relays if the on period is of insufiicient duration for pick up of these code comprising a relatively long on period, followed by a relatively short off period can also be used, provided the time elements of relays K L and DR are suitably adjusted, or code frequency tuning of all wayside and locomotive decoding relays is used. Obviously, the detection code may be of any suitable character, provided it does not pick up relays DR or DR and provided further that it operates relay TR in such manner as to pick up relays K and L When the train enters section F-G, relays TR- K and L will all become deenergized, and the auxiliary code transmitter ACT will become energized over back contact 25 of relay L and will furnish a detection code to section E-F, same manner that the detection code was furnished to section D E, as previously described,

to energize relay XR'over front contacts l4 and I5 of relays K and L thereby stopping the operation of signals X3 The picking up of relays K and L train from section EF will cause transmitter ACT to become inoperative due to opening of relay L .It should be noted.

signal S to indicate stop by virtue of the closing of back contacts 21 and 33. As soon as the train clears section FG, train governing current of code frequency, suitably selected by code selection apparatus which is not shown in the drawing, will be supplied by transmitter CT to transformer T thereby causing operation of relay TR which results in the energization of relays K and L The opening of back contact 2! of relay L will stop the operation of transmitter ACT and track section E-F will then be supplied with current of 80 code frequency over the periodically operated contact 29 of relay TR. and front contact 28 of relay L Relay TR? will follow the 80 code and will relay this code to track section D-E and 26 of relays TR and L in the same martner that it previously relayed the detection code supplied by transmitter ACT As soon as the block in advance of section F-G is cleared by the train, train governing current of '180 code Since section F-G is the last section in the block DG, no special detection code such as that furnished by transmitters ACT and ACT is required in this section because any of the standard train governing codes furnished by transmitter GT can be used to clear relays K and L The on and off periods of the train overcontacts 25 5 thereby 3 the individual sections with in the which follows the exit of the governing codes being of substantially equal duration, relays K and L the same release time, which is true of relay groups K L and not necessarily K L in which can have approximately groups the relays K and K should preferably have a substantially longer releasing time than relays L and L to insure satisfactory operation on a detection code having a short on and a long oil period. If a detection code comprising a long on and a short off period is used, relays L and L will have a longer release interval than relays K and K but when the latter code is used, the increased release time of relays L and L may cause a sli ht delay in the starting of the crossing signals KS and KS To summarize, we have provided a track circuit clearing or train detecting system which requires a number of control line wires, does not interfere with the operation of wayside or cab signals, and permits relaying oi the train governing and detection codes to several rear sections without requiring additional line wires and apparatus for purpose.

It will be apparent that our system can also be adapted for operation on coded direct current track circuits, by substituting direct cu:- rent code-following track relays for the relays TR, and by eliminating the track transformers T and substituting a direct current source for the alernating current source BX-CX.

Should foreign current be present, or a mechanical defect develop in either of the codefollowing relays TR or TR resulting in a failure of front contact 8-18 to open, theassociated relay L or L will become deenergized, removing train governing code from the rear track circuits up to the wayside signal location D, and causing signal S to indicate stop. Similarly, should back contact 9-ll fail to both relays of group K L or K U, will become-deenergized, and the stop indication will again be displayed by signal S.

It will be noted that the circuit for the crossing signal control relay XR. includes a front contact of each of relays L and K Although the use of front contact 55 of relay L would alone be sufiicient to check that relay TR is following code, the inclusion of front contact it of relay K makes possible a quicker response of relay for starting operation of the crossing signal, since relay K is arranged to release before relay L Although we have herein shown and described only one form of apparatus embodying our 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 our invention.

Having thus we claim is:

1. In combination, a first and a second section of railway track eachnorroally supplied with a train governing code comprising rail current periodically varied at a frequency selected in accordance with traffic conditions in advance of said sections, means efiective when said second section becomes occupied for discontinuing the supply of said train governing code to said first section and for supplying the rails of said first section with a detection code comprising periodically varied current having consecutive periodic variations of unequal duration, a codefollowing track relay for said first section capable of following either oi said two codes, a siow acting relay controlled by said track relay in such manner as to become energized when the track relay is following either of said two codes and to become deenergized when the described our invention, what track relay is shunted, an indicator controlled by said slow acting relay for indicating the occupancy of said first section, and a signal for governing trafiic entering said first section con trolled by said track relay and responsive to operation of the track relay on said train governing code but not said detection code.

2. In combination, a first and a second section of railway track each normally supplied wit-h a train governing code comprising rail cur rent periodically varied at a frequency selected in accordance with trafiic conditions in advance of said sections, means effective when said second section becomes occupied for discontinuing the supply of said train governing code to said first section and for supplying the rails of said first section with a detection code comprising periodically varied current having consecutive periodic variations of unequal duration, a codefollowing track relay for said first section capable of following either of said two codes, a slow acting relay controlled by said track relay in such manner as to become energized when the track relay is following either of said two codes and to become deenergized when the track relay is shunted, an indicator controlled by said slow acting relay for indicating the oc-- cupancy of said first section, a. signal for governing traffic entering said first section controlled by said track relay and responsive to operation of the track relay on said train governing code but not said detection code, and means effective when both said sections become unoccupied for discontinuing the supply of said detection code and restoring the supply of said train governing code.

3. In combination, a first and a second section of railway track, means for supplying to the rails of said second section a train governing code comprising current periodically varied at a frequency selected in accordance with traflic conditions in advance, a first code-following track relay for said second section capable of following said train governing code, a first control relay which becomes energized when said first track relay is following said train governing code and which becomes deenergized when said first track relay is shunted, a source of detection code comprising periodically varied current having consecutive periodic variations of unequal duration, means including a back contact of said control relay for rendering said source eifective for supplying said detection code to the rails of said first section, a second code-follow ing track relay for said first section capable of following either of said two codes, a second control relay which is energized when said second track relay is following either of said two codes and which becomes deenergized when said second track relay is shunted, a signal controlled by said second control relay for indicating the occupancy of said first section, and means including a front contactof said first control relay effective when said first track relay is following said train governing code for relaying the train governing code from said second section to the rails of said first section.

i. In combination, a section of railway track normally supplied with a train governing code comprising rail current periodically varied at a frequency selected in accordance with traffic conditions in advance of the section, means for at times discontinuing the supply of said train governing code and for supplying the rails of said section with a detection code comprising periodically varied current having consecutive periodic variations of unequal duration, a codefollowing track relay for'said section capable of following either of said two codes, and a train indicator for said section controlled by said track relay in such manner as toprovide one indication when said track relay is following either of said two codes and to provide another indication when said track relay is shunted.

5. In combination, a section of railway track normally supplied with a train governing code comprising rail current periodically varied at a frequency selected in accordance with traffic conditions in advance of the section, means for at times discontinuing the supply of said train governing code and for supplying the rails of said section with a detection code comprising periodically varied current having consecutive periodic variations of unequal duration, a codefollowing track relay for said section capable of following either of said two codes, a slow acting relay controlled by said track relay and capable of bridging the operation thereof when the track relay is following either of said two codes, and a train indicator for said section controlled by said slow acting relay. 6. In combination, a section of railway track normally supplied with a train governing code comprising rail current periodically varied at a frequency selected in accordance with traffic conditions in advance of the section, means for at times discontinuing the supply of said train governing code and for supplying the rails of said section with a detection code comprising periodically varied current having consecutive periodic variations of unequal duration, a codefollowing track relay. for said section capable of following either of said two codes, a first slow acting relaycontrolled by said track relay and capable of bridging the operation of the track relay on alternate periodic variations of said two codes, and a second slow acting relay controlled by said track relay and said first slow acting relay and capable of bridging the operation of the track relay on alternate periodic variations of said two codes occurring between said first mentioned alternate periodic variations, and a train indicator for said section controlled by said second. slow acting relay.

7.'In combination, a first and a second section of railway track, a first coding device for supplying said second section with a train governing code comprising rail current periodically varied at a given frequency, a first code-following track relay for said second section, a second coding device effective'for supplying a detection code to said firstsection when said first track relay is shunted, said detection code comprising periodically varied rail current having consecutive periodic variations of unequal duration, means including a code-following contact 'of said first track relay for relaying said train governing code to the railsof said first section when said 7 second section is unoccupied, a second codefollowing track relay for said first section capable of following either of said two codes, and a train indicator for said first section controlled by said second track relay in such manner as to assume a first condition when the second track relay isfollowing either of said two codes and to assume a second condition when the second track relay is shunted. V

8. In combination; a stretch of railway track divided into an approach and a clearing section, means for supplying said clearing section with a train governing code comprising coded alternating current having substantially equal on and off periods, a first code-following track relay for said clearing section, means effective when said first track relay is following code for supplying said train governing code to the rails of said approach section, means eifective when said first 7 substantially equal on and off periods, means for at times discontinuing the supply of said train governing code and for supplying the rails of said section with a detection code comprising coded alternating current having on and oil" periods of unequal duration, train governing apparatus responsive to said train governing code but unresponsive to said detection code, a code-following track relay for said section, and a train indicator controlled by said track relay in such manner as to provide one indication when said track relay is following said train governing or said track clearing code and to provide another indication when said track relay is shunted.

10. In combination, a stretch of railway track intersected by a highway and comprising a signal approach section and a signal clearing section, a crossing signal for the intersection, means effective when said clearing section is unoccupied for supplying both said sections with a train governing code comprising coded alternating rail current having substantially equal on and off periods, coding means responsive to the entry of a train into saidclearing section for supplying said approach section with a detection code comprising coded alternating rail current having on and off periods of unequal duration, train governing apparatus responsive to, said train governing code but unresponsive to said detection code, means responsive to the entry of a train into said approach section for causing operation of said crossing signal, and means associated with said approach section and responsive to said train governing code and said detection code for clearing said crossing signal when the train clears said approach section.

11. In a coded wayside and cab signaling system for highway crossings on railroads in which a train governing code comprising coded alternating current having substantially equal on and off periods is normally supplied to the rails for governing wayside and cab signals, the combination with a signal at the crossing, of means for actuating said signal effective when a train enters the section approaching said signal, and means effective when the train clears the approach section for supplying a detection code to the rails of the approach section for clearing said signal, said detection code comprising coded alternating current having unequal on and off periods the relative time values of which are adjusted in such manner as to prevent response of the wayside and cab signals on said detection code.

comprising coded alternating current having 12. In combination, two adjoining sections of railway track, means for supplying coded rail current to one of said sections, a code-following track relay for said one section, a decoding relay responsive to code operation of said track relay, and means including a contact of said track relay and a contact of said decoding relay for supplying rail current to the other of said two sections.

13. In combination, two adjoining sections of railway track, a source of coded current and a code-following track relay connected with the rails of one of said sections, a decoding relay responsive to code operation of said track relay, a slow acting relay controlled by said decoding relay, and means including a contact of said track relay and a contact of said slow acting relay for supplying rail current to the other of said two sections.

14. In combination, two adjoining sections of railway track, means for supplying one of said sections with rail current of a first or of a second code in accordance with trafiic conditions, a code-following track relay for said one section, a decoding relay which becomes energized in response to operation of said track relay on either said first or said second code, means including a back contact of said decoding relay for supplying rail current of said first code to the other of said two sections, and means including a contact of said track relay for supplying rail current of said second code to said other section.

HERMAN G. BLOSSER. CHARLES W. FAILOR.

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