Патент USA US2408208код для вставки
Sept.» 24, 1946. F.T.FEREDAY 2,408,206 ‘ ' APPARATUS FOR RAILWAY SIGNAL SYSTEMS Filed Jan. 6, 1944 s Sheets-Sheet 1 [a INVENTOR a ‘haw ' ' . Hi1’ ATTORNEY _ Sept. 24, 1946. F. T, FEREDAY 2,408,206 APPARATUS FOR RAILWAY' SIGNAL SYSTEMS Filed Jan. 6, 1944 ’ - s Sheets-éheet 2 S R R1 N » E2 ‘la INVENTOR ?pdepia ZVZweday “aim ' H11’ ATTORNEY Sept. 24, 1946. F. T. FEREDAY ' Q 2,408,206 APPARATUS FOR RAILWAY SIGNAL SYSTEMS Filed Jim. 6, 1944 s Sheets-Sheet 3 BYa . m1’ AT-TORNEY ‘ . 2,408,206 Patented Sept. 24, 1946 ‘UNITED STATES PATENT OFFICE APPARATUS FOR RAILWAY SIGNAL SYSTEMS ' Frederick T. Fereday, Louisville, Ky.,.assignor to ' The Union Switch and Signal Company,.Swiss vale, Pa., a corporation of Pennsylvania Application January 6, 1944, Serial No. 517,197 2 Claims. (01. 246-38,) , 1 My invention relates to apparatus for railway signal systems, and more particularly to appara tus for such systems using coded track circuit energy. ./ . Railway signal systems using coded direct cur— rent track circuits are not‘ dependent upon a transmission line which is subject to broken line wiresv caused by weather and other conditions. Heretofore the arrangement for coded direct cur 2 is constructed to be mechanically tuned to havea ' predetermined frequency of oscillation, and thus ‘the track circuit current is periodically inter rupted at a rate corresponding tothe oscillating frequency predetermined for the code transmit ter. Preferably, the code transmitter is. con structed‘with a second armature which is- biased so that this second armature is operated vonly when the energizing current ?owing in the-wind rent track circuits has been to use two sources 10 ing of the transmitter is-of a relatively high value. of current, a relatively large 10 or 12 volt battery for operating the code transmitters and a single cell or low voltage battery for the track circuit. Such two battery'arrangement adds‘ to thecost Thissecond armature is adjusted to remain-at‘ its biased ‘position with the respective track circuit unoccupied and to be attractedlto a’ picked-up interposed in the connection between the track proach control. As an alternative, the second armature of the'transmitter can‘be replaced by position when a train enters the section to shunt ‘and maintenance. ‘Also there is a certain loss 15 the rails and the track circuit current is increased. This second armature is‘ used to provide an ap 'of energy in the current limiting resistor usually battery and the rails. ' f Accordingly, a feature of my invention is the provision of railway signalsystems incorporating ‘novel and improved track circuit coding appa a relay, the winding of which is connected. in 20 series with the code transmitter winding in the track battery connection, and this relay is ad- , justed to be picked up only when the track circuit current is increased due to a train occupying the Another feature ‘of my invention is the provi-" sion of apparatus for track circuits using coded direct current wherewith only a single battery is 25 The approach control apparatus also includes means governed by the code following track relay required. ' * to supply feed-back current impulses to the track Again, a feature of my invention is the provi rails during each off code period of the track cir sion of track, circuit apparatus of the type here ratus. section. ' _ cuit current and an approach relay connected to involved wherewith the code transmitter is con- > nected in series with the track battery taking the 30 the rails through a contact carried on the ?rst armature of the code transmitter. This last men place of the usual current limiting‘resistor and tioned contact is closed as the ?rst armature-is the energy usually consumed in such resistor is moved to its attracted position, and the ap utilized for operation of the code transmitter. proach relay is connected across the rails each oil Still another feature of my invention is the provision of railway signal apparatus incorporat 35 code period of the track circuit current to re ceive the feed-back currentimpulse supplied to ing novel approach control means to cooperate the rails at the relay end of the track circuit. As with coding track circuit apparatus to effect an an alternative, this approach relay may be con approach control for two sections in advance of nected across the'rails through a, recti?er dis a train. ,Other features, objects and advantages em 40 posed to pass the feed-back impulses, but block the flow of current from the usual track battery. bodyingmy invention will appear as the speci?ca This approach control relay and the second ar tion progresses. ‘ S mature of the code transmitter provide two ap The features, objects and advantages embody proach control conditions, one of which becomes ing my invention are accomplished by providing effective when a train enters the section next in a low voltage code transmitter that is operable the rear of the associated section, and the sec from the usual low voltage track battery, and ap— ond of which condition becomes effective when proach control apparatus of the “feed-back” code the train enters the associated section. , principle arranged to cooperate with such trans _ If more than two different control conditions ;mitter. This code transmitter is made to operate of the coded track circuit current are required, on the. energy usually consumed in the current the traffic controlled circuits are arranged to vlimiting resistor interposed between the track Pole change the connection of the track battery, battery and the track rails and it is connected in the code transmitter‘ being operable with equal series with the track battery through a contact e?iciency by current of either polarity. In this _;on;a ?rst armature ‘of the transmitter causing _,such ?rst armature to oscillate. Thetransmitter 56 way the track circuit current is coded at a pre 2,408,206 4 3 termined by the weight and construction of the parts. By way of illustration to aid in under standing my invention, I shall assume that trans selected code rate, and is of either positive or negative polarity according to traffic conditions. When the track circuit is polarized, a polarized code following track relay is provided. Again, mitter CT is constructed for armature 4 to have Cl more than two different control conditions may an operation frequency of 15 times per minute, it being in engagement with each contact 6 and ‘l be provided by using code transmitters of differ ent predetermined operation frequencies and ar for substantially one-half of each operation cycle. The second armature 5 is spring or otherwise biased to a released position and is attracted against the force of its bias to a picked-up posi tion when the transmitter is energized at a rela ranging the tra?ic controlled circuits to selec tively connect these transmitters into the track circuit according to di?erent traffic conditions. I shall describe three forms of apparatus em tively high preselected energy level. That is, bodying my invention, and shall then point out when code transmitter CT is supplied with cur rent of a relatively low value but su?‘icient for the novel features thereof in claims. In the accompanying drawings, Figs. 1 and 2 are diagrammatic views showingia ?rst and a 15 proper operation of the ?rst armature 4, the second armature 5 is retained at its released po second form of apparatus, respectively, embody ing my invention when used with polarized track circuits. Fig. 3 is a diagrammatic view showing a form of apparatus embodying my invention for track circuits using currents of different code 20 rates. ~ g ‘ In each of the three views like reference char acters are used to designate similar'parts. Referring to Fig. 1, the reference characters 1a and lb designate the rails of a stretch of rail way over which tra?ic normally moves in the direction indicated by an arrow, and which rails are formed by insulated rail joints with consecu tive track sections of a signal system, and of which sections only the one section D--E and the adjoining ends of the two adjacent sections are shown, because these are sufficient to illustrate the principle of my invention. Each track section is provided with coded track circuit apparatus, control relays, wayside sig nals and approach control apparatus. sition by that when current of a relatively high value ?ows in winding 8, armature 5 is picked up to engage a front contact 9, the armature 4 being operated at its predetermined frequency by such increased current. _ Code transmitter CT is energized by track battery BE, winding 8 and contact 4—-6 being interposed in series in the connection of track battery BE to the rails of the section D-E. To be explicit, a circuit can be traced from positive terminal B3 of battery BE, either through front contact I!) of a relay ED to be referred to later, or through front contact II of a relay EH, also to be referred to later, and back contact l2 of relay ED, wire l3, thence through winding 8 and contact 4—6 of the transmitter, wire I4 to rail lb, through the track relay of the associated vtrack section, to be described hereinafter, or 35 through a train shunt if a train occupies the sec tion, track rail la, and wire 15 to the center The type of wayside signal to be used is im material, and signals SD and SE for section D—E terminal C of battery BE. Again, a circuit can immediately in the rear. The supply means for the track circuit of sec tion D—E includes a track battery BE and a code transmitter CT. The battery BE is pref is of a normal or relatively low value, and the second armature 5 of the code transmitter re mains at its released position. If a train occu pies the section the track circuit current is in creased and the second armature 5 is picked up to close front contact 9. The code following track relay means for the track circuit of section D——E may be any one of be traced from the negative terminal N3 of bat tery BE through back contacts l6 and I2 of re and the section next in advance of section D-—E are of the color light type capable of displaying 4:0 lays EI-I and ED, respectively, wire I3 and thence as previously traced to the center or mid termi a red lamp R, a yellow lamp Y and a green lamp nal C of the battery. Thus, when relay ED is G, for stop, approach and clear signal indica picked up to close front contact II], or relay EH tions, respectively. is picked up to close front contact H, and relay The track circuit apparatus for each section EDis released to close back contact l2, the track includes supply means connected across the battery BE is connected to the rails of the sec rails at the exit end of the section and code tion D~—E through the code transmitter and the following relay means connected across the rails track circuit is supplied with coded current of at the entrance end of the section. Thus at the what I shall'call positive polarity. When both junction of adjacent sections, such as location E, for example, there are placed the code 50 relays EH—-and ED are released, the track circuit current is coded and it is of what I shall call following relay means for the track circuit of negative polarity. If the track section D-—E is the section immediately in advance and the unoccupied, the value of the track circuit current supply means for the track circuit of the section erably of the split battery type having a posi tive terminal B3, a negative terminal N3 and a mid terminal C. Thus this battery is capable of supplying current of either polarity at the low voltage used for track circuits. The code transmitter CT may take different forms, and preferably it is of the relay type. Transmitter CT is provided with a ?rst armature or contact member 4 and a second armature or several different arrangements of the polarized type. In Fig. 1, two code following neutral relays DR! and DR2 are connected in multiple to the rails through recti?ers I l and I8, respectively, the arrangement being such that relays DRI and D'RZ are operated by current of positive and negative polarity, respectively. The connection contact member 5. The ?rst armature A is biased by weight, or otherwise, to a ?rst posi of relay DRI can be traced from rail lb through tion where it engages a contact 6 and is attracted to a second position where it swings out of en 70 wire i9, recti?er IT in its forward direction, winding of relay DRI, wire 20, back contact 2| of gagement with contact 6 and into engagement a relay DH to be referred‘ to shortly, and wires 22 with a contact 1 when a winding 8 of the trans and 23 to rail la. The connection for relay DB2 mitter is energized. With winding 8 energized through contact 4-6, the armature 4 oscillates between its two positions at a frequency prede extends from rail la through wire 23, recti?er [8 in its forward direction, winding of relay DR2,. 2,408,206 5 wire 24, back contact 25 of a relay DD_ to be re inspection of the drawings taken in connection, ferred toishortly, and wires 26 and I9 to rail lb. It‘ follows that relay DRI' is code operated ‘when coded track circuit current of positive polarity with the description ofthe control of relays EH' and ED. , ‘ . , ‘The, approach control apparatus for section is'supplied to the track circuit in the manner ex D—E includes means at the entrance end of the section to supply a feed-back current impulse, and an approach'relay AR having two associated repeater relays AP and APP and another ap It is to be pointed out that code following track relays ‘ERI and ERZ for the track circuit of the proach relay FTP at the exit end of the section. section next in advance of section D—E are con 10 The means for supplying a feed-back current'im plained hereinbefore, and‘ relay DR2 is operated by track circuit current of negative polarity. nected to the rails in a manner similar to the relays DRI and DB2 and relays ER! and EFR2 are operated in response to coded track circuit current of positive and negative polarity, respec tively, supplied to the track circuit of the section 15 next in advance. - Relays DD and DH at location D are control relays governed by the code following track re lays'DRl and DB2, and these controlrelays goV- _ em in turn the‘ signal SD and the track circuit for the section next in the rear of section D—E. _pulse includes a condenser 39 and a current source. With either relay DRZ picked up to close front contact 40, or relay DRI picked up to close front contact 4|, condenser 39 is charged by a circuit connected to a battery which may be track battery BD at location D, or a separate battery. This charging circuit extends from terminal B3 of the associated battery through either front contact 40 or 4|, condenser 39 and to terminal N3 ofthe same source of current, through a con nection, not shown, but which circuit connection Similarly, control relays ED and EH at location E are governed by the track relays ERI and ERZ would be similar to the connection of a condenser 42 at location E, and which latter condenser sup and these control relays govern in turn the sig plies the feed-back current impulse for the track nal SE and the track circuit for section D—E, 25' circuit for the section next in advance of section Looking at location E, relay EH is governed by ' D—E, and ‘which connection for condenser 42 in~ relay ER2 through a condenser 21, which func cludes back contact 43 of ‘relay AP and either tions as a secondary source of energy. ' When re front contact 44 of relay FTP or front contact 45 lay ERZ is picked up, the condenser 21 is con of relay APP. Condenser 39 is connected across nected to a charging circuit which includes a bat 30 the rails of'the section D—E through alternative tery the terminals of which are designated Bill‘ circuit, paths, one of which extends from one and NH), ‘and which charging circuit. extends terminal of the condenser through back contact ‘from terminal BIO through front contact 28 of 46 of relay DRZ, front contact 41 of relay DH and‘, wires 26 and l9v to rail lb; and from the relay ER2, condenser 21, wire 29, and to terminal N l 0 through three alternative paths which in 35 other terminal of the condenser through front clude front contacts 30, 3| and 32 of relays AP, contact‘ 49 of relay DH'a-nd Wires22 and 23 to FTP and APP, respectively, and which relays are rail la. The other circuit path extends from one a part of the approach control apparatus to be terminal of condenser 39 through back contact described hereinafter. Then, when relay ERZ is 59 of relay DRI, front contact 5| of relay DD and released to close back contact 33, the condenser .40 wires 22 and 23 to rail la; and from the other 27 is connected across a winding of relay EH and terminal of the condenser throughfront contact relay EH is energized due to the discharge of the -52 of relay DD and wires 26 and I9 to rail lb. condenser. Consequently, when relay ER2 is op Consequently, when track relay DRZ is operated erated at a code rate, the control relay EH re at code and the approach control relays for the ceives an energizing‘ impulse each code cycle, and section next in the rear are conditioned so as to it is retained picked up from one code cycle to complete the connection of the charging circuit the next by virtue of a slow release period pro for condenser 39 to'the terminal N3 of the asso ’vided for the relay due to a recti?er 34 connect; ed across its winding. Such energization of re lay'EH is effected, however,yonly if one of’ the ‘ ciated battery, the condenser 39 is charged each on ‘code period, and is connected across the rails to discharge and‘ provide a feed-back code im approach relays AP, FTP or APP is picked up to pulse each off code period. It is to be observed close the respective front contact 30, 3| or 32. that this feed-back current impulse is of a po In a similarmanner, the track relay ER! con-v larity reverse to that of the track circuit cur trols relay ED.. Relay ER! when picked up com rent that operates the track relay DRZ. In like pletes a charging circuit for a condenser 36, such manner, code operation of track relay DRI con circuit extending from terminal ‘BIO through nects condenseri39 to a charging circuit each front contact‘35 of relay ERI, condenser 36, wire‘ on code period and connects the condenser across the rails each o? code period to supply a feed :29 and to terminal NIB by the three alternative circuit paths explained in connection with the back current impulse due to the discharge of the charging’ circuit of condenser 21. When relay 60 condenser, the feed-back current impulse being ERI is released, closing back contact 31, con of a polarity reverse to the polarity of the track denser 36 is connected to a winding of relay ED circuit current that operates track relay DRI. and relay ED is energized by the discharge of the Approach relay AR‘ is connected‘ across the condenser. Relay ED is made slow to release by rails through second position contact 1 of arma a recti?er 38 connected across its winding and ture 4 of the code transmitter CT and thus relay remains picked up from one code cycle to'the 'next. Control relays ED and EH govern the 7 connection of battery BE to the‘ track circuit for section D—E as explained hereinbefore, and also govern operating circuits for the associated sig 70 nal SE in a manner to be explained when they op eration of the apparatus is described. Control relays DH and DD at location D are a, controlled by track relays DR! and DRZ through, condensers 51 and 18 as will be apparent by an 75 AR is conditioned to receive the feed-back cur rent impulse supplied to the rails throughcon denser 39 in the manner explained above, R'e peater relay AP is energized by an obvious cir cuit including front contact 53 of relay AR and is retained picked up during code operation of relay AR due to the slow release characteristic of relay AP effected through a condenser con nected across its Winding, Repeater relay APP isprovided with an obvious 2,408,206 7 pick-up circuit including front contact 54 of re-' lay AP, and with a stick circuit which includes its own front contact 55 and back contact 5'6 of relay FTP. Relay FTP is energized through an obvious circuit including contact 5——9 of code transmitter CT. 8 off code period which causes in turn approach relay AR at location E to be operated and the associated repeater relays AP and APP to be energized. The closing of front contact 3!] of relay AP completes the circuit by which condenser 21 is charged, and consequently the control relay EH is energized in response to code operation of track relay ER2. Relay EH on picking up to close substantially the same as that described for sec 10 front contact I I switches the connection of track tion D—E. battery BE and the track circuit of section D—E In describing the operation of the apparatus is supplied with coded current of positive polarity of Fig. 1, I shall assume that section D—E, as Each of the remaining track sections or the signal system of Fig. 1 is provided with apparatus causing track relay DRI to be operated in place of track relay DRZ; With relay DR] operated, tra?‘lc condition, code operation of either track 15 the associated control relay DD is energized be cause condenser 18 is now changed each on code relay ER! or ER2 is ineffective to bring about period due to the contact corresponding to con the energization of the respective control relays tact 3| of relay FTP being closed at the cor ED and EH because the charging circuits for the responding relay for the section next in the rear. associated condensers 35 and 21 are held open at Relay DD on picking up to close front contacts front contacts 39, 3! and 32 of the approach con 5! and 52 completes the connection for the feed rol relays AP, APP and FTP of section D—E. back impulse for section D—E. Also, the pick With control relays EH and ED deenergized, well as the section next in the rear and the sec tion next in advance are unoccupied. Under this track battery BE is connected to the rails of sec ing up of relay DD to close front contact 60 ing circuit for condenser 42 is normally open at front contacts 44 and 45 of the approach rear of section D—E because the control circuits of signal SE are held open at front contact 58 condenser 39 is open at the contacts of the ap D-E at the time the ?rst assumed train is trae versing the section next in the rear of section D—E, the train in the section next in advance shunts relays ERI and ERZ and both control relays EH and ED are deenergized causing the track circuit current for section D—E to be of negative polarity so that track relay DRZ at location D is operated and control relay DH is energized in response to the charging and dis completes a circuit by which green lamp G of tion D--E for the track circuit to be supplied with‘ coded current of negative polarity, and 25 signal SD is illuminated, this circuit being com' pleted through contacts of the approach control which coded current operates the track relay relays for the section next in the rear in a man DRZ at location D. Operation of relay DB2 at ner similar to the control circuit for lamp G this time is ineffective to govern‘ the associated of signal SE at location E and which latter control relay DI-l, because the charging circuit for condenser 51 through which relay DH is con 30 circuit is completed at front contact 58 of relay FTP and back contact 6| of relay AP when a trolled is not completed at the associated ap train has entered section D—E. Consequently proach control relays in the same way the charg signal SD is approach lighted to display'a clear ing circuit of condenser 21 at location E is not signal, and feed-back impulses are supplied to completed through the contacts of the associated ' 35 section D—E. approach control relays of section D—E, It is to be noted that signal SE remains dark No feed-back current impulse is provided for while the train occupies the sectio'n'next in the the section next in advance because the charg control relays FTP and APP, respectively, Like 40 of relay FTP and at back contact 6| of relay AP. It is to be observed that if another train oc wise, no feed-back current impulse is supplied cupies the section next in advance of the section to section D—E because the charging circuit for proach control relays for the section next in the rear in the same manner that the connection of condenser 42 at location E is normally open at the approach control relays APP and FTP. Conse quently, under normal conditions, all control re lays and approach control relays are deenergized and all wayside signals are dark. It is to ‘be observed that in place of each track circuit being normally supplied with coded cur rent of negative polarity, as illustrated in Fig. 1, the polarity of the track circuit current may be reversed for alternate track sections to aid broken down insulated rail joint protection. I shall next assume that a train enters the sec tion next in the rear of section D—E. The shunting of the rails of the section next in the rear increases the ?ow of track circuit current for that section, and the second armature of the as sociated code transmitter is picked up to close its front contact, and which contact corresponds to contact 9 of transmitter CT. This causes the approach relay for the section next in the rear, and which relay corresponds to approach relay FTP, to be picked up through the second arma- , ture contact of the associated code transmitter, and that relay on picking up closes contacts that correspond to contacts 3!, 44 and 58 of relay FTP. The closing of the front contact that cor responds to front contact ‘44 of relay FTP com pletes a connection by which the condenser 39 is charged each on code period, so that condenser 3-9 now supplies a feed-back current impulse each charging of condenser 57. With‘ control relay DH picked up the feed-back impulses are sup plied as before, and with front contact 63 closed and relay DD released‘to close back contact 62, the yellow ‘lamp Y of signal SD is illuminated for the signal to display an approach indication. I shall next assume that the ?rst mentioned train advances and enters section D—E, the sec tion next in advance being considered as un occupied. The shunting of the rails of section D—E shunts the track circuit current from the relays DR! and DR? and also the feed-back current impulse from relay AR. The shunting of both track relays DR! and DR2 causes both con trol relays DD and DH to be deenergized with the result the R lamp of signal SD is illuminated through a circuit including back contacts 52 and E05 of relays DD and DH. The shunting of ap proach relay AR causes this relay to be released and the repeater relay AP is deenergized and released at the end of its slow release period. The shunting of the rails of section D—E causes an increase in the track circuit current so that armature 5 of the code transmitter CT is picked 2,408,206 9. I upl to-ibrin'g about the" energizing ofrl‘approa'ch ’ 10 relayfor‘ the section next in advance and which approach‘ relay corresponds to 'relay AR ‘for section fD'-E, track rail, :Ia wire :15‘, front relay FrP; f'I-‘he 7pickin'gi'up ofi'relay FTP opens ba'cljicontact 56 in the v‘stick circuit vfor relayv APP vcontact 1-6 ‘of ‘relay EH,‘ Wires Tl andl'l?, back contact. 43 of relay 'AP and either front contact MS of relay'FTP or front contact 45 of relay APP to'fterminal N3. "This feed-back current impulse up to? close vfront contact 44, the charging. cir thus supplied to the rails of'the section next in euit'ror: condenser 42 is completed vand feed-back advance‘ will operate the approach relay that cor current~ impulses ‘are ‘no-WY supplied to the rails ior 'thesection next in; advance to‘ govern the 10 responds-to-relay. AR and effect the approach and? thatrelay' ' is deenergiz'ed ‘ subsequent ‘to. ‘the Trele'aseofi relay AP.‘ Withlr‘elay AP "released to fclosevbackicontact 43 and relay FTP. picked approach‘ relay at -the;-eXit_'*end of-‘the section, and which approach relaycorresponds to relay control apparatus-for that section. ,If relayERl lamp-Y of- signal SE according to which con tr'ol relay ED or EH is‘ picked up in. response to traffici-conditions in‘ advance of section D—E. tra?ic conditions and a description of .the' opera is'code operated the circuit for the ‘feed-back impulse ‘is completed at front contacts ‘I04 and Release .of relay 'APLto'close back contact HIE-of relay ED} It is apparent that the appa 61$; and? the ‘picking up of relay FTP to close front contact‘ 58 completes-the operating “ circuit to 15 ratus of Fig.1?“ will operate in a manner similar illuminate either the green lamp'G or the yellow I \ to the apparatus of .Fig. 1 under the di?erent tion of the apparatus of Fig. 2 need not befur 'ther described. Ifa‘se'cond train occupie's‘the section in'advance ' 7’ ~ " » IniFig.-~3,~in- which a form‘ of apparatus em- bodyingimy invention using different code rates is’ disclosed, the stretch of railway is arranged and‘ED, (closing back contacts 64 and '65, with track sections and wayside signals the same the 'red'lamp Rv of signal'SE ‘is illuminated as a as in Fig. 1, and each section is provided with stop signal indication. ' -In the'case the increase‘oftrack circuit current 25 tracklcircuit apparatus, signal control relays and approach control relays, the same as in Fig. 1. when .thetrain ?rstenterssection D—E is not sufficient to pick up the second armature 5' of The supply means forgthe track circuit of sec tion D-I—E of Fig. 3 comprises a battery BEI and code transmitter CT and the current'does not reach» the value at which the second armature two code ‘transmitters CT15- and CTIBU, The iis'vpicked up until‘thetrain has advanced some :30 codetransmitters C'I‘J5 and CTIBII are similar distance into v‘section D—E, the relay ‘APP is re in construction tolcodetransmitter-CT of Fig. 1, tained'picked up by its stick circuit and the oper transmitter 'CT'I5 being constructed to have an atin‘gwci-r'cuit‘ for signal SE is completedat front operation frequency bf '75 times per minute, and to bringv about the release of both‘ control relays > . contact?? of relay APP. Also'the charging cir transmitter-CT! 80 an operation frequency ‘of 180 cuitsirforcondensers 21 and 36 are completed at lfrbntaconta'ct .32 of relay APP, and the charging 35 times per minute. It will be understood; of ‘circuit for the condenser 42 is completed atl'front contact" 45 of relay APP'until' suchtime as ‘the armature 5 of the code transmitter is-operated to bring about the energization of relayvFTP. selected forlthese- code transmitters.’ These'two transmitters arei‘also adjusted for their respec-_ 'tive second armatures 19 and 80to be picked up course, that other operation frequenciesimay be 140 at the same preselected'relatively high value of current that was provided for transmitter CT. Battery BEI is-connected to the rails of the asso relays ER! and ERZ, both control relays‘ ED ‘and ciated section through one or the other of ‘the EH are‘relea'sed so that the track circuit'fo'r sec transmitters} a ?rst ‘connection including front tion D—E is again supplied with current offnega jtive polarity and the apparatus is restored to ‘its 45 contact 8 I‘ of control relay EH, winding-and con tact 82 of transmitter CTI8U, track rail lb; track 'Tr'elay or train shunt and track rail Ia and wire > . In Fig.2, the" apparatus is the same as thatf-in Fig. 1, except vfor the means for s'up'plying'éthe ' ‘83 to‘ the other'terminal of battery BEL A' sec When this train vacates ‘section 'D--—E shunting normal condition. ~ ‘ ‘ - ' ~ ~ ‘ ‘ 1 ond connectionincludes back contact 84 of con vfeed-back current impulse, ‘and thefapparatus "at locationgE only is'shown because this issu?icie'nt 50 n01‘ relay"EH,' winding and contact $5 of trans mitter'QT'IS and thence as previously traced for the ?rst circuit connection. Thus when control me my invention. In Fig.2 thefeed-back cur relay EH is energized, the track circuit for‘track ;rent'impu‘lse is obtained from the track'battery or'preferably a separate battery of equivalent section D_—~E is supplied with coded current of voltage, and a relay. Looking at location E of 55 the1180fcode rate, and when relay EH is released Fig. 2, and assuming that track relay ERZ is being the track circuit current is of the '75 code rate, the polarity'of' the current‘ being the same for operated- in response to coded track circuit cur both conditions.'7 ~ : » "(rent-for the section next in advance of section _Track relay DB3 for the section D—‘E is a 'D-I-E, a circuit for energizing a relay EF is formed ‘each off code period, such circuit being traced 60 direct current code following relay connected "across the rails through'a recti?er 86 which is from terminal B3'of the respective source of cur poledto passcurrent of the polarity supplied by rent,‘ through back contacts 68 and .61 'ofrelays battery 'BEI, and'to block the feed-back current ER] and‘ERZ, winding of relay EF, a recti?er-6B, ‘impulse- used for ‘control of vthe‘approach con :wire 10,‘back'co_ntact.43 of relay AP and either trol apparatus to be described shortly. At loca: front-contact; 44 of relay FTP or front contact 45 'tion E; track ‘relay EH3 associated with’ the track Hot‘ relay APP to terminal N3Pof> the same- source ‘ ‘to fully illustrate this form of apparatus embody concurrent. Relay'E'F is providedwith a slow “section-next in? advance is‘ connected to the rails *i'pick-up-period which ‘isv something " less" thanv the in-a manner similar to that oftrack relay DB3. Track relay DB3 governs control relays DH and on code period of the track circuit current." Dur ing this slow pick-up period of relay EF,-'- current 70 DD through a repeater relay TPD and a decod knows‘ from terminal B3 through back contacts in‘g unit’ IBUDU. ,Similarly, track relay ER3 gov »68¢‘-and761,“back contact’ ‘H of relay‘EF, resistor " erns associated control ‘relays EH and ED ;‘-'|-_2;ffronticontact13 of relay EH which is‘ picked 'l-I' ldueto code operationsoflrelay ‘EH2, wire 14 to through a"v repeater‘ relayTPE and a decoding funit ,FIBODU. "Looking at location E, track relay Iran Iii-through theywinding-bf thelappr'o'ach 75 sER'3lwhen ‘picked up ‘to close front contact 88 ' 2,408,206 11 12 completes an obvious circuit for energizing re relay APD released to close back contact 91 a charging circuit is completed for a condenser 95 through which feed-back current impulses are supplied to the rails of section. D—E. This charging circuit for condenser 95 extends irom terminal B3 through front contact 96 of track relayDR3, condenser 95, back contact 91 of relay APD and front contact 98 of control relay DH to peater relay TPE, and which circuit is completed through front contact 30, 3| or 32 of the relays AP, FTP or APP in the manner explained in connection with Fig. 1. It follows that when re lay ER3 is operated at code, the repeater relay TPE is operated at a corresponding code pro viding the approach control relays are properly terminal N3. Condenser 95 is connected across conditioned. With‘ relay TPE picked up to close front contact 89, condenser 81 is charged through 10 the rails through back contact 99 of relay DB3 and is discharged to supply a feed-back current a circuit completed at front contact 30, 3! or 32, impulse. This feed-back current impulse is of a and condenser 81 is discharged through the polarity to energize approach relay AR at loca winding of control relay EH when repeater re tion E which‘ relay in Fig. 3 is connected across lay TPE is released to close its back contact 90, during each off code period. With relay EH thus 15 the rails through a recti?er I00 poled to block the current supplied by track battery BEI. Ree picked up in response to code operation of track lay DB3 will not be energized by this feed-back relay EH3, the closing of front contact 9| of current impulse due to recti?er 86. With ap relay EH completes a circuit for supplying cur proach relay AR operated by the feed-back cur rent impulses to the input side of the decoding unit IBDDU through front and back contacts 92 20 rent impulses, its associated repeater relays AP and APP are energized. With relay AP picked and 93 of repeater relay TPE.‘ Decoding unit up to close front contact 30, the energizing cir I8IJDU may be of any one of the several well cuit of repeater relay 'I‘PE and the charging known arrangements, and is shown convention circuit of condenser 81 are completed and con ally for the sake of simplicity. It is su?icient to point out that when current impulses supplied’ to 25 trol relay EH is energized‘ in response to code operation of the track relay ER3. Control relay the input side of the unit are of the 180 code EH on picking up to close front contact 8'! con rate the control relay ED connected to the out nects battery BEI to the rails through code trans put side of the unit is energized and picked up, but that when the code impulses are of the 75 mitter CTI80, so that the trackrcircuit for sec code rate, the control relay ED is deenergized 30 tion D~E is now supplied with‘ current of the 180 code rate, withthe result that control relay and released. Control relays EH and ED, to DD is energized and signal SD is controlled as gether with the approach control relays for sec requiredto display a clear signal indication. tion D~—E govern the operating circuits for sig nal SE the same as in Fig. 1. Control relays DH ‘ In the event a second train occupies the‘ sec and DD at location D are controlled by repeater 35 tion next in advance of section D--E, the shunt ing of track relay EH3’ causes oontrolrelay EH relay TPD in a manner similar to that by which relays EH and ED are controlled by relay TPE‘. to be released so‘ that the track. circuit current for section D--E is of. the 75 code rate, with the The approach control apparatus of Fig. 3 is resultcontrol relay DH is picked up but control similar to that described for Fig. 1, and it is believed that this approach control apparatus of 40 relay DD is released and signal SD is controlled as required to display an approach signal indi Fig. 3 can best be understood from a description cation. I of the operation of the apparatus. It is to be ' When the train advances and enters section understood, of course, that location D of Fig. 3, and each similar location are provided with‘ ap D—E, the shunting ‘of the rails causes an in paratus similar to that for location E of Fig. 3. crease in the track circuit current and the sec ond armature of either codetransmitter C'I‘l5 Normally, that is, when section D—E and the adjacent sections of Fig. 3 are unoccupied, track or CTI80 is picked up with the result the ap relay EH3 is code operated, but control relay EH proach relay FTP is energized to close front con and in turn control relay EDv remain deenergized tact 3|. The feed-backrcurrent impulses for the because the circuits for the repeater relay 'I'PE 50 section’ D—E are now shunted so that approach and condenser 81 are not completed at contacts relay AR and its repeater relay AP are deener gized. Control relay EH remains energized be 39, 3| or 32 of the associated approach control cause the connection for repeater relay TPE and relays. With relay EH released, closing back contact 84, the track circuit for section D—E condenser 8‘! is now closed at front contact 31 is of the '75 code rate, and track relay DB3 is 55 of relay FTP. With relay'AP released and re lay EH picked up, a charging circuit for a con operated at a corresponding code rate. Thus, in denser l03 is formed from terminal B3, front Fig. 3, all control relays and approach‘control contact [B8 of relay EH3, condenser I93, back relays are normally deenergized and the signals contact I9! of relay AP and front contact I02 are dark. of relay EH to terminal N3. Condenser I 03‘ is I. shall next assume’ that a train enters the then discharged through back contact 10‘! of section next in the rear of section D—E. This track relay ER3 for supplying a. feed-back cur causes the track circuit current for the section rent impulse to the rails of the section next in next in the rear to be increased, and the respec advance. With back contact 61 of relay AP and tive second armature of the code transmitter is picked up so that the relay corresponding to 65 front contact 58' of relay FTP closed, the operat ing circuits for signal SE are completed and- the relay FTP of section D--E isienergized. This clear or approach lamp of the signal is illumi closes a front contact corresponding tofront. con nated according to the condition of control re tact 3d of relay FTP with the result the repeater lays EH and ED. relay TPDv is operated to bring about the control of relay DH, condenser 94 acting as a secondary The apparatus here disclosed has the advan tage that a single battery only is: required for source of energy in the control of relay DH. each track circuit supplied with coded direct cur Approach relay ARD and its repeater relay APD rent, different traf?c conditions being re?ected at location D will be deenergized due to the shunting of the feed-back impulses by'this train by'the' polarity and coderate of the current. ' Also entering the section’ next in the rear, and with '75 approach control apparatus cooperating with 2,408,206 13 ‘ 14 such track circuit is effective to provide approach a ?rst and a second signaling means controlled control for two sections in advance of a train. Although I have herein shown and described by'said track relay and said second transmitter contact member respectively. 2. In combination with a railway track circuit only three forms of apparatus for railway sig nal systems embodying my invention, it is under stood that various change-s and modi?cations may including the rails of a track section and a track relay connected across the rails at one end of the section and a track battery connected across the rails at the other end of the section, a code transmitter having a ?rst contact member bi scope of my invention. // Having thus described my invention, what I 10 ased to a ?rst position and operable to a second . position when its Winding is energized, said con claims is: V tact member at its ?rst position and said wind 1. In combination with a railway track circuit be made therein within the scope of the append ' ed claims without departing from the spirit and including the rails of a section and a track re- . lay connected across the rails at one end of said section, a source of direct current, a code trans mitter having a ?rst contact memberbiased to a ?rst position where it engages a ?xed contact and operable to a second position where it is out of engagement with said ?xed contact when a winding of the transmitter is energized, circuit ing in series interposed in the connection of said track battery to code the track circuit current for code operating said track relay when the sec tion is unoccupied, a second contact member for said code transmitter and which second contact member is biased to a ?rst position and is oper ated to a second position only when the trans mitter is energized at a relatively high value of current to close a front contact when a train means including said ?xed contact and said con occupies said section to shunt the rails, supply tact member to connect said current source means controlled by said track relay when code across the rails at the end of said section oppo operated to supply to the rails an impulse of site said one end through said winding to code current each code period the track relay is de— 25 the current supplied to said track circuit for op energized, a ?rst signaling means including said erating said track relay at said code when the ?rst contact member at its second position ener section is unoccupied, a second contact member gized by said current impulses when the section operable by said transmitter to engage a ?xed is unoccupied, and a second signaling means in contact only when said transmitter winding is cluding said front contact and a current source energized at a relatively high value of current 30 energized when a train occupies the section. to close' the last mentioned contact only when a train occupies the section to shunt the rails, andv FREDERICK T. FEREDAY.