US2998513A

US2998513A - Train control system

Info

Publication number: US2998513A
Application number: US821911A
Authority: US
Inventors: Taczak John; John C Elder
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1959-06-22
Filing date: 1959-06-22
Publication date: 1961-08-29
Anticipated expiration: 1978-08-29
Also published as: GB908441A

Description

Aug. 29, 1961 J. TAczAK ET AL 2,998,513

TRAIN CONTROL SYSTEM Filed June 22, 1959 2 Sheets-Sheet 1 wrwl ETUI.

Aug. 29, 1961 1. TAczAK ET AL 2,998,513

TRAIN CONTROL SYSTEM Filed June 22, 1959 2 Sheets-Sheet 2 Jaim Taezak mi M111 C. Euer a). A. THEIR ATTRNEY mired rates Our invention relates to a train control system, and particularly to an arrangement for controlling the movements of trains of cars from a receiving yard to the crest of the hump in a gravity or hump type railway car classication yard.

In railway freight operations the road engines pull their trains of cars into what is commonly known as a receiving yard located at a division point or other point on the railroad where the cars must be reclassified into new trains according to class, destination, etc. The receiving yard usually consists of a number of storage tracks where each train of cars arriving is stored until the classification yard is available for reclassifying the cars in the train. In some track layout arrangements the storage tracks all connect over one or more hump lead or shove-up tracks to a single track in approach to the hump in a gravity or hump type classication yard. Switch or humping engines shove the trains of cards up the shove-up tracks to the vicinity of the crest of the hump where each car or groups of cars of a similar classification are separated from the rest of the train by a brakeman and then proceed by gravity to their proper classication tracks.

In order to provide for safer operation in such railway operations it has been found expedient to provide a system whereby indications can be given to the engineman of the shove-up engines whether they are to proceed with the shove-up movement of their train of cars or to stop. Such a system is especially important in track layouts where two or more shove-up` tracks leading to the hump approach track exist, and more than one switching engine may be shoving trains of cars` up different shove-up tracks preparatory to the movement of the cars over the hump for classification purposes. It is accordingly one object of our invention to provide an economical system for furnishing indications to the enginemen of the shove-up engines which inform each engineman whether he is to proceed with his train movement or to stop.

It is another object of our invention to provide said indications independent of any conductors such as the rails of the track or cable or line wires between the apparatus controlling the indications and the indicators for giving the indications to the enginemen.

It is a further object of our invention to provide an indicating system of the type describedin which it is insured, insofar as practicable, that an indication to proceed into the hump approach track will not be given to more than one engineman at a time.

Other objects and characteristic features of our invention will become apparent as the description proceeds.

In accomplishing the foregoing objects of our invention we employ a wireless communication system over which signals are transmitted, under the control of manually operated devices to indicator control apparatus for each engine, to the engineman of which it is desired to give indications. n

We shall describe one form of apparatus embodying our invention and shall then point out the novel features thereof in claims.

essere rie In the drawings:

FIG. 1 is a diagrammatic view showing a simplified track layout, and the manual control devices and associated apparatus for controlling the transmission of the indicator control signals.

FIG. 2 is a diagrammatic view showing the communication arrangement and associated apparatus for transmitting and receiving the signals for providing the indications to the enginemen of the shove-up engines.

It is believed expedient at this time to point out that hereinafter in this description the term signal shall refer to a signal transmitted over said wireless communication system, as the term is often employed in the wireless or radio communication art.

It is also believed expedient at this time to point out that the wireless communication apparatus employed in our invention and illustrated in FIG. 2 is shown, for purposes of simplification, in block diagram form since the details thereof form no part of our present invention and such apparatus is well known. The power supply for operation of the communication apparatus is not shown in the drawings but is intended to be considered as included in the block diagrams representing said communication apparatus. This apparatus will be discussed more fully hereinafter in this description.

Referring now to FIG. 1 there is shown at the top of the drawing, in single line form, a track layout including a stretch of single track extending from a track switch, designated by the reference character SW, in the right hand direction on the drawing, to a point designated as the crest of hump which is intended to indicate the crest of the hump in a gravity or hump type railway car classification yard. This single track stretch is sometimes referred to hereinafter as the main track, the hump approach track, or merely as the single track. Extending in the left-hand direction on the drawing from switch SW are two stretches of

track

1 and 2 sometimes referred to hereinafter as yard` tracks, shove-up tracks, multiple track leads, or `hump approach track leads. The yard tracks converge at switch SW to form the hump approach track. Railway cars `being moved toward the hump for classification move in the direction indicated by the arrow above the track layout.

Three insulated track sections are provided in the tracks of the track layout. One of these sections is designated HAT and extends, Yfrom a point just short of the crest of the hump, to the point of fouling or clearance in each of the yard tracks. The remaining two insulated track sections designated `1T and 2T are located in

tracks

1 and 2, respectively, and each extends from the point of clearance in yits respective yard track to a predetermined point on that track so :as to lform a track section of suicient minimum length that it cannot be spanned by the 4trucks and wheels of the longest railway car or engine to be moved over the track,

Eachof the insulated track sections is provided with a track circuit including a source of :track circuit current and atrack relay in a manner well known in the art such that the trackA relay is energized when no car or engine occupies the track section. For purposes of simplicity the sources of current are not shown in the drawing, and the track relays designated 1TR, ZTR and HATR for track sections 1T, ZT 'and HAT, respectively, are shown connected to their respective track sections `in a conventional manner 'by `a dotted line extending from each tnack section to the respective track relay.

There is shown on the left-hand side of FIG. l a plurality of manually operable push-pull type of circuit controllers designated iFITTIPB, F2T1PB, FITZPB, and lF-ZTZPB. These controllers are shown disposed on a panel, designated as a receiving yard control panel, but

may be mounted in any manner desired and at any location convenient to the personnel who are to control the shove-up train movements from the receiving yard toward the rest of the hump. These controllers are each shown as having a movable contact a normally closed against a back contact point and operable to close against a front contact point when the respective controller is depressed. Controllers FIT-IPB and FZTlPB are noted on the drawing Las interlocked with each other, and are also of the stick type. That is, when one of these controllers is pushed or depressed, it will remain in that operated position until it is pulled to return it to its normal position, or until the other controller is depressed. Upon the depression of said other controller the interlocking feature of the controllers operates the first controller to open its front contact point before the front contact point of the subsequently depressed controller closes. Controllers FITZPB and FZTZPB are also interlocked with each other and are of the stick type, and operate in a manner identical to that described Vfor the other two interlocked controllers.

There is shown on the lower right-hand side of FIG. l an `additional manually operable circuit controller designated SCL and comprising a lever operated contact member designated CM. This controller is shown as normally occupying a center or o position in which the contact member is closed `against a contact point designated 0, and is operable to left and right-hand positions designated T1 and T2, respectively, in which the contact member is closed against contact points designated l and 2, respectively. This circuit controller is shown disposed on -a hump control panel but may be mounted in any manner desirable `and `at any location convenient to the personnel who are to control the actual train humping movements. Although in most hump type classification yards the movements of trains from the receiving yard to a position for humping `and the train humping operations themselves are controlled by diierent personnel, and, therefore, the receiving yard control panel and the hump control panel would usually be located at different locations as shown in FIG. l, it is to be understood, that the manually operable circuit controllers shown in our drawings as disposed on two separate panels could be located so as to be controlled by fthe same person without departing from the scope of our invention. The purpose of the described manually operable circuit controllers will be more fully set forth later in this description.

Referring further to FIG. `l, there is shown a group of relays designated FITISR, 'F2T1SR, F1T2SR, and FZTZSR. These relays are modulating frequency control stick relays for

yard tracks

1 and 2, and repeat, in a manner to be hereinafter described, the operation of an associated one of manually operable controllers FlTlPB, F2T1PB, FITZPB, or F2T2PB. Relays LOPR, LT2SR and LTISR in FIG. l are relays yactuated by the operation of the manually operable controller SCL and the operation of these relays will also be described later in this description.

Two additional relays designated HAITSR and HAZTSR are shown in FIG. l. These relays are track repeater stick relays which serve to provide control for circuits, the proper operation of which depends on whether a train enters track section HAT from

yard track

1 or 2. The operation of these relays will be described in detail later in this description.

There is shown at the top of FIG. 2 of the drawings the transmitting or communication apparatus employed in our invention for the transmission of control signals to the enginemen on the shove-up engines, and the circuit arrangement for controlling the transmission of said signals. The transmitting apparatus is shown as including a transmitter or carrier oscillator, modulator, and amplifier unit designated TMU. This unit generates a carrier frequency which is supplied to output terminal b on the unit and thence to a transmitting antenna designated TANT. The carrier frequency generated by unit TMU is selectively modulated by two audio frequencies supplied to input terminal a of the unit over signal selection circuits, to be described, from output terminals a and b of an audio oscillator unit designated AOU. These audio modulating frequencies are designated No. l and No. 2 and are supplied from the output terminals a and b, respectively, of u nit AOU. While we have shown only two such audio modulating frequencies it is to be understood that any number of such frequencies could be employed to transmit additional signals within the scope of our invention. The apparatus for generating, modulating and amplifying the signals to be transmitted is shown in the drawings in block diagram form because, as previously mentioned, the details of this apparatus form no part of our present invention and such apparatus is well known.

On the lower part of FIG. 2 of the drawings is shown two sets of signal receiving and indicator equipment designated engine A equipment and engine B equipment. lOnly two sets of such equipment are shown because in the specific example of our invention described herein only `two audio modulating frequencies are employed and, therefore, only two engines are shown provided with such equipment. However, in actual practice each engine to be employed as a shove-up engine would be provided with a set of the equipment and the equipment of all engines to be working simultaneously as shove-up engines would be tuned to be responsive to a different audio modulating frequency, the number of such fre quencies employed being increased to correspond to the number of engines employed simultaneously as shoveup engines. For example, assuming that four yard tracks exist leading to a hump approach track in a track layout similar to that shown in FIG. 1, two, three or four shove-up engines could be working simultaneously. and a different audio modulating frequency would be assigned to each such engine. Arrangements would also be provided to assign any of the frequencies to any of the four yard tracks. This will become more apparent later in this description.

Referring further -to the aforementioned engine equipment, the equipment on engines A and B is, with the exception of the modulating frequency to which the equipment is tuned, identical, engine A equipment being assumed to be tuned to audio frequency No. l and engine B equipment to audio frequency No. 2. Therefore, only the equipment lfor engine A will be described in some detail. The receivers or carrier amplifiers, frequency selection, and audio amplifier units designated ARU and BRU for engines A and B, respectively, are shown in block diagram form because the details of these receivers or receiving units, similarly to the previously described transmitting apparatus, form no part of our present invention and such receiving units are well known.

Referring now to the engine A equipment, there is associated with receiving unit ARU an intenna designated ARANT which receives the signals transmitted by the transmitter TMU and supplies the signals to an input terminal a on receiver ARU. The frequency selection portion of the receiver selects or is responsive only to audio modulating frequency No, 1 and if the carrier frequency received is modulated by that audio frequency an output is produced at output terminal b of unit ARU which is supplied to a demodulator relay designated ASCR to thereby pick up that relay. A contact a of relay ASCR functions to control lamps of an indicator designated ACS in a manner described hereinafter.

A source of current such as a battery of proper voltage and capacity is provided for the indicator associated with each of the shove-up engines A and B. These sources of current for purposes of simplicity are not shown in the drawing, but the positive and negative terminals of these sources are designated AEB and AEN cessera `respectively', and BEB and BEN, respectively, for ,the indicators for engines A and B, respectively.

When the carrier frequency transmitted by unit TMU is not modulated by audio frequency No. l, demodulator relay ASCR described above is released and a circuit is closed over the back point of contact a of that relay to energize the S or stop lamp of indicator ACS. This circuit extends from terminal AEB of the associatedsource of current over the back poi-nt of contact a of relay ASCR and through the iilament of said S lamp to terminal AEN of said source. The S lamp is thus illuminated and indicator ACS gives a stop indication.

When transmitter TMU is transmitting the carrier frequency modulated b-y audio frequency No. l, in a manner to be hereinafter described, demodulator relay ASCR will pick up, opening at the back point of its contact a the energizing circuit for lamp S of indicator ACS, and closing at the front point of its contact a the energizing circuit for the Y or proceed lamp of indicator ACS. This circuit extends from terminal AEB of the source over the front point of Contact a and through the `filament of the Y lamp to terminal AEN. Lamp S of indicator ACS is thus extinguished and lamp Y is illuminated to indicate to the engineman of engine A that he may proceed.

The engine B equipment, as previously stated, is identical to and operates in an identical manner as that of engine A except that the frequency selection portion of the receiving unit BRU of engine B is' tuned to be responsive to audio modulating frequency No. 2. Antenna BRANT, receiver unit BRU, demodulator relay BSCR and indicator BCS correspond, respectively, to the described equipment of engine A designated ARANT, ARU, ASCR and ACS.

lt is believed expedient at this time to point out that a source of current such as a battery of proper voltage and capacity is provided for operation of the apparatus shown in FIG. l. However, for purposes of simplicity, this source is not shown in the drawingsI but its positive and negative terminals are designated B and N, respectively.

It should also be pointed out in the drawings that the contacts of the various relays are not in all instances located below the rectangles representing the windings of the respective relays, but in each instance in which a contact is not so located ift is identified by the reference character designating its respective relay disposed on the drawing directly above the movable portion of the contact. This arrangement is believed readily apparent from a brief glance at the drawings.

Referring again to FIG. l of the drawings and speciiically to relays FTlSR, FZTISR, FlTZSR, and FZTZSR, the control circuits for these relays will now be described. Relay FlTlSR has a pickup circuit which extends from terminal B of the battery over the back point of contact a of controllcrrFZTlPB, the front point of contact a of controller FlTllPB in its depressed or actuated position, back contact b of relay FiTZSR, back contact b of relay FZTISR, and through the Winding of relay FlTlSR to terminal N of the battery.

Relay F2T1SR has a pickup circuit which extends from terminal B ofthe battery over the back point of contact a of controller FlTlPB, the front point of contact a of controller FZTIPB in its depressed or actuated position, back contact b of relay F2T2SR, back contact b of relay FlTlSR, and through 'the winding of relay FZTiSR to terminal N of the battery.

Relays F\1T1SR and FZTlSR each have a stick circuit part of each of lwhich is a multiple circuit common to both stick circuits. These circuits extend from terminal B of the battery over back contact c of relay :ITR or over back contact c of relayHAlTSR, and thence over front contact a of relay FITSR through the winding of that relay to 'terminal N of the battery, or overfrontcontact a of relay FZTSR through the winding of that relay to terminal N of the battery p Relay FITZSR has a piokupcircuit which extends' from 6 terminal B ofthe battery over the back point of contact ai' of controller F2T2PB, the front point of Contact n of controller F1T2PB in its depressed or actuated position, back contact c of relay F lTlSR, back contact c of relay FZTZSR, and through the winding of relay FTZSR to terminal N ofthe battery.

Relay FZTZSR has a pickup circuit which extends from terminal B of the battery over the back point of contact a of controller F1T2PB, the front point of contact c! of controller FZTZPB in its ldepressed or actuated position, back contact c of relay FZTISR, back contact c of relay FlTZSR, and through the winding of relay F2T2SR to terminal N of the battery.

Relays EITZSR and F2T2SR each have a stick circuit part of each of which is a multiple circuit com-mon to both stick circuits. These circuits extend from terminal B of the battery over back contact c of relay ZTR or back contact c of relay HAZTSR, and thence over front Contact a of relay FITZSR and. front contact n of relay FZTZSR through the windings` of the respective relays to terminal N of the battery.

The purpose of the back points of contacts a of controllers FlTSlPB and FZTPB in the pickup circuits for relays FZTlSR and FlTlSR, respectively, is to provide a check that the previously described interlocking between the two controllers is intact and operating. The back points of contacts a of controllers FITZPB and FZTZPB in the pickup circuits of relays FZTZSR and FTZSR, respectively, provide a similar check on the interlocking between those two controllers. The back contacts of relays F1T2SR and FZTILSR in the pickup lcircuits for relays Fl'DISR and FZTZSR insure that these latter relays cannot be picked up to assign audio modulating frequency No. l to track l or audio modulating frequency No. 2 to track 2 when these frequencies are, as hereinafter described, respectively assigned to track- 2 and track 1, as' reected by relays FITZSR and FZTISR, respectively, being maintained picked up over their stick circuits. Similarly, the back contact of relays FITISR and F ZTZSR in the pickup circuits for relays FZTlSR and `FITZSR insure -that these latter relays cannot be picked up to assign audio: modulating frequency No. 2 to track 1 or audio modulating frequency No. 1 to track 2 when these frequencies are, as hereinafter described, respectively assigned to track 2 and track 1, as reflected by relays FZTZSR and FlTlSR being maintained picked up over their stick circuits. The utility of this arrangement will become more apparent later in this description. v l

The control circuits for relays HAlTSR and HAZTS-R shown in FIG. l will now be described. Relay HAITSR has a iirst pickup circuit extending from terminal B of the battery over front contact a of relay HATR and through the winding of relay HAITSR to terminal N of the battery. Relay HAITSR has a second pickup circuit extending from terminal B of the battery over back contact b of relay HAZTSR and through the winding of relay HAITSR to terminal N of the battery. Relay HAlTSR has a multiple stick circuit extending from terminal B of the battery over -front contact a of relay lTR or front contact c ofrelay LTZSR, and thence over front contact a of relay HAITSR and through the winding of the relay to terminal N of the battery.

Relay HAZTSR has a `first pickup circuit extending from terminal B of the battery over front contact b, of relay HATR and through the winding of relay HAZTSR to terminal N of the battery. Relay HAZTSR has a second pickup circuit extending from terminal B of the battery over back contact b of relay HAITSR and through the winding of relay HAZTSR to terminal N of the battery. Relay HAZTSR has ya multiple stick circuit extending from terminal B of the battery over -front contact z of relay 2TR or front contact c olf relay LTlSR, arid thence over front contact a of relay HAZTSR and through the winding of the relay to terminal N ofthe battery. The operation and purpose of relays HA 1TSR 7 and HAZTSR will be described more `fully later in this description.

Relay LOPR shown in FIG. 1 is a slow release relay as indicated by the arrow drawn in the downward direction through the movable portion of contacts a and b of the relay in the pickup circuits, to be described, for relays LTZSR and LTlSR, respectively. Relay LOPR yrepeats the o position of controller SCL, that is, a pickup circuit for the relay is closed when lever SCL is in its olf position. This circuit extends from terminal B of the battery through movable contact member CM of controller SCL, contact of controller SCL and through the winding of the relay LOPR to terminal N of the battery. The purpose of the relay and its slow rerelease feature will be discussed hereinafter.

Relay LTISR in FIG. 1 is employed to at times repeat the T1 position of controller SCL, that is, a pickup circuit -for the relay is prepared when controller SCL occupies its T1 position and is closed when either relay 1TR or HATR is released. This circuit extends from terminal B of the battery over said movable portion CM of controller SCL, contact 1 of controller SCL, back contact b of relay ITR and back contact c of relay HATR in multiple, and thence over said front contact b of relay LOPR and through the winding of relay LTlSR to terminal N of the battery. Relay LTISR has a stick circuit including its own front contact a which by-passes said Contact b of relay LOPR in the described pickup circuit for relav LTISR.

Relay LTZSR in FIG. 1 is employed to at times repeat the T2 position of controller SCL, ythat is, a pickup circuit for the relay is prepared when controller SCL occu-pies its T2 position and is closed when either relay ZTR or HATR is released. This circuit extends from terminal B of the battery over said movable portion CM of controller SCL, contact 2 of controller SCL, back contact b of relay 2TR and back contact d of relay HATR in multiple, and thence over said front contact a of relay LOPR and through the Winding of relay LTZSR to terminal N of the battery. Relay LTZSR has a stick circuit including its own front contact a which by-passes said contact a of relay LOPR in the described pickup circuit for relay LTZSR.

Front contacts a and b of relay LOPR in the pickup circuits for relays LTZSR and LTlSR, respectively, insure that these latter relays cannot be picked up following a previous pickup and release of the respective relay, without first `returning controller SCL to its olf position. The slow release feature of relay LOPR insures that contacts a and b of that relay will remain closed for a suicient period of time to permit relay LTISR or LTZSR to pick up when controller SCL is moved from its off position to position T1 or T2, respectively. The utility and operation of relays LOPR, LTISR and LTZSR will become more apparent as this description proceeds.

Referring again to the signal transmitting arrangement shown at the top of FIG. 2 of the drawings, the control circuits for supplying audio modulating frequencies No. l and No. 2 from unit AOU to transmitter unit TMU will be described.

Modulating frequency No. l Awhen assigned to track 1, as hereinafter described, is supplied from output terminal a of unit AOU to input terminal a of unit TMU by iirst and second circuit paths, the first extending from said output terminal a over front contact d of relay FITISR, front contact d of relay lTR, and front contact e of relay HAITSR to said input terminal a; and the second extending from said output terminal a over said front contact d of relay FITISR, front contact b of relay LTlSR, and over front contact d of relay HAZTSR to said input terminal a. Modulating frequency No. 2, when assigned to track 1 as hereinafter described, is supplied from output terminal b of unit AOU to input terminal a of unit TMU by the same first and second circuit paths first described except that front contact d of relay FZTISR supplies modulating frequency No. 2 to said circuit paths in place of front contact d of relay lFITISR supplying modulating frequency No. l to those paths.

Modulating frequency No. l, when assigned to track 2 as hereinafter described, is supplied from output terminal a of unit AOU to input terminal a of unit TMU by first and second circuit paths, the first extending from said output terminal a over front contact d of relay FlTZSR, front contact d of relay 2TR, and over front contact e of relay HAZTSR to said input terminal a; and the second extending from said output terminal a over said front contact d of relay FITZSR, front contact b of relay LTZSR, and over front contact d of relay HAITSR to said input terminal a. Modulating frequency No. 2,

y when assigned to track 2 as hereinafter described, is supplied from output terminal b of unit AOU to input terminal a of unit TMU by the same first and second circuit paths just descr-ibed except that front contact d of relay FZTZSR supplied modulating frequency No. 2 to said circuit paths in place of front contact d of relay F 1T2SR supplying modulating frequency No. l to those paths.

Having thus described in general the control circuits for the apparatus of our invention, we will now describe the operation of the circuits and apparatus in several specific examples of controlling the movement of trains from the receiving yard to a location near the hump approach track preparatory to the movement of each train over the hump into the classification yard, and the operation of the circuits and apparatus in several specific examples of controlling the movement of each train, one at a time, from said location into the classification yard.

As previously set forth the receiving apparatus of the engine A equipment is assumed to be tuned to be responsive to audio modulating frequency No. l and the receiving apparatus of the engine B equipment is assumed to be tuned to be responsive to audio modulating frequency No. 2. It will be further assumed, for a specific example, that the employee operating the receiving yard control panel decides to route train A over track 1 and train B over track 2 to their positions preparatory to humping each train. (For purposes of simplicity in the remainder of this description the operator of the receiving yard control panel will hereinafter be referred to as the yardmaster and Ithe operator of the hump control panel will hereinafter be referred to as the hump conductor.) The yardmaster, therefore, depresses controller FlTlPB to assign audio modulating frequency No. l (shove-up engine A receiver being tuned to that frequency) to shove-up track 1, and also depresses controller FZTZPB to assign audio modulating frequency No. 2 (shove-up engine B receiver being tuned to that frequency) to shove-up track 2. The engineman of each of the shove-up engines is informed, prior to said manipulations, which of the shove-up tracks he is to travel.

The depressing of controllers FlTlPB and FZT-ZPB as described above closes the previously traced pickup circuits for relays FlTlSR and FZTZSR, respectively, and these relays pick up and will remain picked up so long as their respective controller remains depressed, the controllers being of the stick type as previously described. The pickup of relay FlTl-SR closes front contact d of that relay in the control circuits for the transmitting apparatus (FIG. 2), and modulating frequency No. l, to which engine A equipment is responsive, is supplied to transmitter rFMU over the previously described circuit including front contacts d and e of relays 1TR and HAITSR, respectively. Similarly, the pickup of relay FZTLSR closes front contact d of that relay in the control circuits for the transmitting apparatus, and modulating frequency No. 2, to which engine B equipment is responsive, is also supplied to transmitter .T MU over the previously described circuit including front contacts d and e of relays ZTR and HAZTSR, respectively. The carrier frequency of transmitter TMU is thus modulated by both audio frequencies, and transmitted in that modulated form from antenna TANT of unit TM'U to antennas ARANT and BRANT of receiver units ARU and BRU, respectively.

The receipt of the carrier signal modulated by the audio frequency to which each of the receiver units is tuned causes pickup of demodulator relays A'SCR and BSICR to change the indications of indicators ACS and BOS, respectively, from the stop indication to the proceed indication as previously described, and engines A and B can proceed, when ready to do so, over their assigned shoveup tracks in the direction of the crest of the classification yard hump.

It is desired to point out that the indications given by the aforesaid indicators rem-ain under the control of the yardmaster until each shove-up engine traveling its assigned shove-up track occupies the track circuited track section in the respective track. (The operation of the apparatus When one of said track sections is so occupied Will be described hereinafter.) Therefore, the yardmaster may, up to the time of such occupancy, change the indication of each indicator from proceed to stop by pulling the proper depressed controller to return it to its undepressed position and thereby open the pickup circuit for the respective control relay FlTllSR or F2T2SR. The yardmaster may also cancel a proceed indication by depressing a controller which is interlocked with the controller which established that indication; thereby causing the latter controller to return to its normal or undepressed position. However, this manipulation will result in the assignment of another audio frequency to the respective shove-up track if said other audio frequency is not already assigned to some other shove-up track.

The back contacts of the control relays FlTlSR, FZTISR, FlTZSR, and FZTZSR in each others pickup circuits prevent the lassignment of one audio frequency to more than one shove-up track at a time. These contacts also serve to provide an additional means to prevent more than one audio frequency being assigned to any one track during the same period of time. It is believed that this will be readily apparent from a brief examination of the pickup circuits for said control relays.

We will now assume that the engineman of engine A, having received the afore-described proceed indication, proceeds over his assigned shove-up track 1 toward the hump and occupies track section 1T, thereby releasing track relay lTR. The release of relay 1TR will open at front contact d of that relay the previously described circuit for supplying audio modulating frequency No. l to transmitter TMU (FIG. 2), and the indicator for shoveup engine A will therefore change its indication from proceed to stop to indicate to the engineman of engine A t take action to do so. The release of relay TTR will also establish the previously described stick circuit for relay F1T1SR including back contact c of relay lTR. Relay F1T1SR being maintained picked up by said stick circuit, the yardmaster no longer has control of the movements of engine A, the control of such movements now being in the hands of the hump conductor as described hereinafter. Maintaining relay F1T1SR in its picked-up position by said stick circuit prevents the yardmaster from pulling controller F1T1PB and thereby releasing relay F1T1SR. Back Contact b` of relay FlTlSR in the pickup circuit for relay FZTISR prevents the assignment of modulating frequency No. 2 to track 1. Similarly, back contact c of relay F1T1SR in the pickup circuit for relay FITZS-R prevents the assignment of modulating frequency No. 1 to track 2. In this manner it is insured that modulating frequency No. l remains assigned to shoveup track 1, that is, under the control of track relay lTR (or track relay HATR as hereinafter described).

We Will now assume that Vthe engineman of engine B, "having received `the 'afore-described proceed indication from engine B indicator, proceeds over his assigned shove- 'itp track 2 tou/ard the hump and occupies track section 2T, thereby releasing track relay ZTR. Similar circuit operation to that described for engine A now takes place. That is, audio modulating frequency No. 2 is no longer supplied to transmitter TMU, due to the opening of front contact d of relay ZTR. The engineman of engine B, therefore also receives a stop indication at this time. Back contact c of relay ZTR in the previously described stick circuit for relay F2T2SR closes to complete that stick circuit, thereby also removing control of relay FZTZSR from the receiving yard control machine and, therefore, from the yardmaster.

It Will now be assumed, for purposes of this description, that the hump conductor decides to classify the cars of train B rst rather than those of train A, although the manipulation is similar in either instance. The pump conductor, therefore, moves lever SCL on the hump control panel from its olf position to position T2 to select track 2 and permit the engineman of engine B to begin car humping operations. As previously set forth, relay LOPR which repeats the olf position of lever SCL is sufiiciently slow to release that front contact a of that relay Will remain closed for a suicient period of time after ylever SCL is moved from its olf position to allow lever SCL to attain its T2 position, thereby closing the previously described pickup circuit for relay LTZSR, picking up that relay and closing its stick circuit including its own front contact a. The subsequent release of relay LOPR opens the pickup circuit for relay LTZSR, but the relay is maintained picked up over its said stick circuit.

The pickup of relay LTZSR closes front contact Vb of that relay in the modulating frequency No. Z Supply control circuit to input terminal a of transmitter TMU, thereby again closing that circuit and again controlling indicator BCS for engine B from its stop to its proceed indication. It will be noted that the hump conductor, if he so desires, can at this time cancel the proceed indication for engine B by returning lever SCL to its off position and give a proceed indication for engine A `by moving the lever to its T1 position. However, as pointed out hereinafter, such operation can only be performed up until the time engine By enters track section HAT.

The engineman of engine B having again received a proceed indication, as previously set forth, now moves his train into track section HAT, thereby releasing track relay HATR. The release of relay HATR opens at front contact b of that relay the pickup circuit for relay HAZTSR which also releases, its stick circuit over front contact a of relay ZTR having been previously opened. The opening of front contact a of relay TR in the stick circuit for relay HAITSR when train A entered track section 1T, prepared the release of relay HAITSR but said stick circuit was again closed when relay LTZSR picked up and closed its front contact c. Therefore, the opening of front contact a of relay HATR in the pickup circuit for relay HAITSR, when engine B enters track section HAT, does not release relay HAllTSR. Furthermore, the release of relay HAZTSR, closes the second pickup circuit for relay HAlTSR over back contact b of relay HAZTSR. Relay HAZTSR having been released as described, its stick circuit is opened at its own front contact a and the relay cannot again be picked up so long as front contact b of relay HATR is maintained open by engine B occupying track section HAT. Therefore, relay HAlTSR cannot be released so long as engine B occupies track section HAT as the relay is maintained picked up over back contact b of relay HAZTSR. Although relay LTZSR can be released and relay LTISR picked up by the hump conductor changing the position of lever SCL at this time, the modulating frequency supply control circuit for supplying modulating frequency No. 1 to transmitter TMU and including front contact b of relay LT1SR, cannot be closed `as the circuit is open at front contact ld of relay HAZTSR. Therefore, a proceed indication to permit engine A to enter track section HAT l 1 cannot be given so long as train B occupies track section HAT.

The engineman of engine Bmay proceed with the car humping operations of his train so long as the hump conductor permits lever SCL to remain in position T2. The hump conductor can cancel the proceed indication for engine B at any time by moving lever SCL to the off position, thereby stopping train humping movements by engine B, and can permit such operations to be resumed by engine B by return of lever SCL to T2 position, and again giving the engineman of engine B a proceed indication.

When shove-up engine B has, by said car humping operations, reduced the size of its train sufficiently that track section 2T is vacated and only track section HAT is occupied. relay ZTR will again pick up. This will open back contacts b and c of relay ZTR in the pickup and stick circuits for relays LTZSR and FZTZSR, respectively; however, back contacts d of relay HATR and c or relay HAZTSR in said pickup and stick circuits, respectively, will remain closed thereby maintaining relays LTZSR and FZTZSR picked up at this time. Therefore, no change in the positions of these relays takes place at this time. The closing of front contact d of relay 2TR in the transmitter supply control circuits does not serve to close the alternate circuit for supplying audio frequency No. 2 to transmitter TMU because this circuit remains open at this time at front contact e of relay HAZTSR. The closing of front contact a of relay ZTR in the stick circuit for relay HAZTSR causes no change in the position of relay HAZTSR as its stick circuit is open at its own front contact a. Engine B may, therefore, continue its car humping movements, no change in the positions of any of the relays, except relay 2TR, taking place when track section 2T is vacated.

When engine B has completed its humping operations it may return to the receiving yard either by moving over the crest of the hump and returning by some return route not shown in the drawings, or by a back-up movement into track section 2T and thence to the receiving yard. If engine B returns by said back-up movement, a proceed indication for the engine to make such movements can be given to the engineman by the hump conductor until the engine vacates section 2T. At that time, back contacts c or relays ZTR and HAZTSR are both open and relay FZTZSR will release opening its front contact d in the audio frequency No. 2 supply circuit to transmitter TMU, unless the yardmaster previously failed to open the pickup circuit for relay FZTZSR by pulling the depresed controller FZTZPB. lf the yardmaster did not so open said pickup circuit, the engineman of engine B will continue to receive a proceed indication. vlf the yardmaster did open said pickup circuit, he can give a proceed indication to engine B by again depressing controller FZTZPB. However, the route by which a shove-up engine returns to the receiving yard is immaterial to our invention and for the purposes of this description it will be assumed that engine B moves over the crest of the hump and returns to the receiving yard by said return route not shown.

When engine B moves over the crest of the hump and vacates track section HAT, relay HATR picks up and the following relay operation takes place. The closing of front contact b or relay HATR closes the pickup circuit to relay HAZTSR which also picks up. The picking up of relay HAZTSR completes, at back contact c of that relay, the opening of the stick circuit for relay FZTZSR which releases providing the yardmaster has previously pulled controlled F2T2PB and returned it to its undepressed position. The opening of back contact d of relay HATR completes the opening of the pickup circuits for relay LTZSR which releases providing this relay was not previously released by the hump conductor returning lever SCL to its off position when the car humping operations were completed. The apparatus is now back in its normal condition and the indicator for engine B gives the engineman a stop indication. Engine B can now return to the receiving yard either running on said stop indication, or by the yardmaster again depressing controller FZTZPB to pickup relay PZTZSR in the manner previously described and thereby giving the engineman of engine B another proceed indication on which to return to the yard by said return route. The hump conductor can now move lever SCL to position T1 and permit the engineman of engine A to commence car humping movements. The operation of the apparatus of our invention in controlling the indications of indicator ACS for the car humping movements of engine A is believed readily understood from the previously described operations in controlling the movements of engine B and, therefore, it is not considered necessary to describe the operations of the apparatus for said movements of engine A. The similarity in operation is readily apparent.

ln order to point out the purpose of relay LOPR in FIG. l it will now be assumed that engine A has completed its humping operations, and has returned to the receiving yard. It will be further assumed that engine B has another train of cars to be classified and has been assigned to track 1 for these operations. It will also be assumed that the hump conductor failed to return lever SCL to the off position following the car humping operations of engine A. The yardmaster depresses controller FZTIPB to assign frequency 2 (and engine B) to track 1 and relay FZTlSR picks up. The further operation of the circuits and apparatus, being similar to that described for the previous movements of engine B, this operation will not be described in detail but it will be assumed that the engineman of engine B receives a proceed indication and moves over track 1 and finally occupies track 1T, thereby releasing track relay ITR. The release of relay TTR opens at front contact d of that relay the circuit for supplying modulating frequency No. 2 to transmitter TMU and the indicator for engine B changes from proceed to stop. The release of relay lTR also closes back contact b of that relay in the pickup circuit for relay LTlSR. Having assumed, as set forth previously, that the hump conductor failed to return lever SCL to its off position and left it in its T1 position following the car humping movements of train A, the pickup circuit for relay LTlSR would now be closed over back contact b of relay lTR were it not for the open front contact b of relay LOPR in said pickup circuit, and relay LTISR would pick up to continue to supply over its front contact b modulating frequency No. 2 to transmitter TMU. However, the open front contact b of relay LOPR in the pickup circuit for relay LTISR requires that lever SCL be returned to its off position, thereby picking up relay LOPR, before relay LTlSR can pick up following its employment for previous car humping movements on track l. Contact a of relay LOPR. in the pickup circuit for `relay LTZSR performs a similar function for relay LTZSR.

From this description it is apparent that with apparatus of our invention arranged as shown in the drawings, an economical train control system is provided for controlling the movements of trains from a receiving yard to a location preparatory to car humping operations in a hump or gravity type classification yard, and for control of the car humping movements themselves without the danger of a train performing such operations being side swiped by another train where multiple tracks lead to the hump approach track. However, it is to be understood that our invention is not confined to receiving yard and gravity type classification yard installations, but may be employed in any installation where multiple tracks converge to form a single or main track.

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 described our invention, whatwe claim is:

l. Ina train control system, in combination, a plurality of yard tracks converging to form a main track, a iirst track section in said tracks extending from a point just beyond the point at which said main track is formed to the clearance point in each said yard track, an additional track section in each said yard track extending from the clearance point for the respective track in a direction away from said main track to aipredetermined point in the track, a track circuit for each said track section each including -a track relay, a plurality of manually operable controllers, a transmitter for transmitting independent of the rails of said track sections a plurality of signals, means controlled by said controllers for selectively assigning a diiferent one of said signals to a diierent one of said yard tracks; means controlled by the last mentioned means and by the track relay for the track section in each saidy yard track for activating said transmitter to transmit, when the respective track section is unoccupied, the signal assigned to that yard track; a plurality of receivers each tuned tot a diierent one of said signals, a plurality of actuable indicators one for each said receiver each Vindicator normally giving a stop indication and capable of giving a proceed indication when actuated, means controlled by each said receiver for actuating the associated indicator when that receiver is receiving the signal to which it is tuned, an additional manually operable controller having normal and multiple operated positions, and means controlled by said additional controller in one of its operated positions and the track relay for one of said yard track sections for reactivating transmission of the signal assigned to the respective yard track following an interruption of the transmission of that signal occasioned by the occupancy of that yard track section.

2. In a train control system, in combination, a plurality of yard tracks to be traveled by trains and converging to forma main track, a iirst insulated track section extending from a point just beyond the point at which said main track is formed to the clearance point in each of said yard tracks, an insulated track section in each said yard track each section extending from the clearance point for that track in a direction away from said main track to a predetermined point on the respective track, a track circuit for each said track section each including a track relay, a transmitter for transmitting signals independent of the rails of said tracks, a receiver on the engine of each said train, each receiver responsive to one of said signals different than that to which any other receiver is responsive, a plurality of manually operable controllers, means controlled by said controllers for selecting each said yard track and selectively -assigning any unassigned one of said signals to the selected yard track; means controlled by the last mentioned means, the track relay for the track section in each selected yard track, and the track relay for said iirst track section for activating said transmitter to transmit the respective assigned signal when the first track section and the track `section for Vthe respective selected yard track are unoccupied; a cab indicator on each said engine each indicator normally giving a stop indication and capable of giving a proceed indication, means controlled by said receiver on each said engine for actuating said 4indicator on that engine to give a proceed indication when said transmitter is transmitting the signal to which that receiver is responsive, a manual control lever Vfor, selecting at dierent times each said yard track; and means controlled by said manual control lever, the track relay for said lirst track section and the track relay for the track section in the yard track then selected by the lever, for reactivating the transmission of the signal assigned to that selected yard track following an nterruption of that signal occasioned by the occupancy of one of those track sections.

3. In `a train control system, in combination, a stretch 'of track ViIicluding a first and a second adjoining track section, a track occupancy detector for each said track section, a transmitter for transmitting a signal independent of the rails of said track sections, an engine to travel said track sections, a receiver on said engine responsive to said signal, `an actuable indicator on said engine normally giving a's'top indication and capable of giving a proceed indication when actuated,V means controlled by said receiver for actuating said indicator when said transmitter is transmitting said signal, a rst manually operable controller having normal and actuated positions, means controlled by said controller in its actuated position and by said track occupancy detector for said first track section for actuating said transmitter to transmit said signal when the first track section is unoccupied, a second manually operable controller having normal and actuated positions;

and means controlled by said second controller in its actuated position and said track occupancy detectors for reactivating, following an interruption of said signal occasioned by the occupancy of one of said track sections, said transmitter to trans-mit said signal so long as the second controller is in its actuated position.

4.V In a train control system, in combination, a stretch of track including a track section, a track occupancy detector for said track section, a transmitter for transmitting a signal independent of the rails of said track section, an engine to travel said ytrack section, a receiver on said engine responsive to said signal, an actuable indicator on said engine normally indicating stop` and capable of indicating proceed when actuated, means controlled by said receiver for `actuating said indicator when said transmitter is transmitting said signal, a first manually operable controller having normal and actuated positions, means controlled by said controller in its actuated position and by said track occupancy detector for actuating said transmitter to transmit said signal when said track section is unoccupied, a second manually operated controller having normal and actuated positions, and means controlled by said second controller in its actuated position -and by said track occupancy detector for actuating said transmitter to transmit said signal when said track section is occupied following a previous transmission of said signal. K

5.,In a train control system, in combination, a plurality of yard tracks to be traveled by trains and converging to form a main track, a first track section extending frorn a point just beyond the point at Which said main track is formed to the clearance point in each of said yard tracks, a track section in each said yard track each extending from the clearance point for that track in a direction away from said main track to a predetermined point on the respective yard track, a track occupancy detector foreach said track section, a transmitter for transmitting a plurality of signals independent of the rails of said tracks, a receiver on the engine of each said train each responsive to one of said signals diiferent than that to which any other receiver is responsive, a plurality of manually operated circuit controllers, means controlled by said controllers and said track occupancy detectors for selectively assigning any unassigned one of said plurality of signals to any one of said vyard tracks and activating said transmitter to transmit the assigned ls ignal so long as said Vt'irst track section and the track section for the respective yard track are unoccupied, an actuable indicator on each said engine each indicator normally giving a stop indication and capable when actuated of giving a proceed indicatiommeans controlled by the` receiver on each said engine for actuating the indicator on that engine When said transmitter is transmitting the signal to which that receiver is responsive, another manually operated circuit controller for selecting each said yard track; and means controlled by said other circuit controller, the track occupancy detector for said lirst track section, and the track occupancy detector for the track section in the yard track selected by said other circuit controller for reactivating said transmitter to transmit -the signal assigned to that yard track following an interruption of the transmission of that signal occasioned by the occupancy of one of those track sections.

6. In a hump type railway car classication yard having multiple yard tracks leading to a single track in approach to the hump, in combination, a trackV occupancy detector for each said yard track, a transmitter for transmitting a plurality of signals independent of the rails of said tracks, a plurality of engines to travel said tracks, a receiver on each said engine each tuned to a different one of said signals, a plurality of manually operable controllers having normal and operated positions, means controlled by each controller in its operated position for assigning a different one of said signals to one of said yard tracks, means controlled by the last mentioned means and the track occupancy detector for said one of said yard tracks for activating said transmitter to transmit the assigned signal when that track is unoccupied to within a predetermined distance of said single track, an actuable indicator on each said engine normally indicating stop and capable when actuated of indicating proceed, means controlled by the receiver on each said engine for actuating the indicator on that engine when said transmitter is transmitting the signal to which that receiver is tuned, an additional manually operable controller having a normal position and an operated position for each said yard track, and means controlled by said additional controller in each operated position and the track occupancy detector for the respective yard track for that position for reactivating transmission of the signal assigned to that track following an interruption of the transmission of that signal occasioned by occupancy of the track.

7. In a train control system, in combination, a plurality of yard tracks converging to form a main track, a track section in each said yard track each extending from the clearance point for that track in a direction away from said main track to a predetermined point on the yard track, a track circuit for each said track section each including a track relay, a plurality of manually operable controllers each having normal and operated positions, a transmitter for transmitting independent of the rails of said track sections a plurality of signals, means controlled by each said controller in its operated position for assigning one of said signals to one of said track sections; means controlled by said last mentioned means and the track relay for each track section for activating said transmitter to transmit, when that track section is unoccupied, the signal assigned to that track section; a plurality of engines to travel said tracks, a receiver on each said engine each tuned to a different one of said signals, an actuable indicator on each said engine each normally indicating stop and capable when actuated of indicating proceed, means controlled by said receiver on each said engine for actuating said indicator on that engine when that receiver is receiving the signal to which it is tuned, an additional manually operable controller having normal and multiple operated positions, and means controlled by said additional controller in one of its operated positions and the track relay for one of said track sections for reactivating transmission of the signal assigned to the respective track section following an interruption of the transmission of that signal occasioned by the occupancy of that track section.

8. In a train control system, in combination, a plurality of yard tracks converging to form a main track, a rst insulated track section extending from a point just beyond the point at which said main track is formed to the clearance point in each of said plurality of yard tracks, an insulated track section in each of said plurality of yard tracks each section extending from the clearance point for that track in a direction away from said main track to a predetermined point on the respective track, a track circuit including a track relay for each said track section, a transmitter for transmitting a signal over a carrier channel independent of the rails of said tracks, a plurality of frequencies for modulating said signal, a receiver on the engine of each train to travel said yard tracks each receiver responsive to said signal and including a frequency selector responsive to one of said frequencies different than each of those to which the other frequency selectors are responsive, manually operable controllers for selectively assigning a different one of said frequencies to each of said yard tracks; means controlled by said manually operable controllers, by the track relay for said first track section, and by the track relay for the track section in each respective yard track for modulating said signal by each respective assigned frequency when said rst track section and the track section in the respective yard track are unoccupied; and manually controlled means partially controlled by each said track relay for reactivating the modulation of said signal by the frequency assigned to each yard track following a previous modulation by the frequenoy assigned to that yard track and an interruption thereof by the occupancy of the track section in that yard track.

9. In a hump type railway car classification yard having a single track in approach to the hump and a plurality of tracks converging into said single track, in combination, means for transmitting independent of the rails of said tracks a diiferent signal assigned to the engine of each train to travel said tracks, signal receiving means on each said engine responsive only to the signal assigned to that engine; an indicator on each said engine controlled by the signal receiving means, Iand normally giving a stop indication and operable to give a proceed indication when the signal assigned to that engine is received; a plurality of manually operable controllers, means controlled by said controllers for selectively assigning a different one of said signals to each of said plurality of tracks and actuating said transmitting means to transmit the assigned signals, a track occupancy detector for each of said plurality of tracks, means controlled by the track occupancy detector for each of said plurality of tracks for deactivating said transmitting means to interrupt the transmission of the signal assigned to that track when the track is occupied within a predetermined distance from the point of convergence with said single track, another manually operated controller, and means controlled by said other controller and each said track occupancy detector for selecting at different times each of said plurality of tracks and reactivating said transmitting means to transmit the signal assigned to that track when the track is occupied within said predetermined distance following a previous transmission of that signal.

References Cited in the tile of this patent UNITED STATES PATENTS 2,550,859 Pickell May 1, 1951 2,606,281 Thomas et al Aug. 5, 1952 2,651,711 Johanek et al Sept. 8, 1953 2,793,287 Phelps i May 2l, 1957 2,948,234 Hughsons Aug. 9, 1960 2,951,452 Karlet Sept. 6, 1960