US2179311A - Remote controlling apparatus - Google Patents

Description

Nov. 7, 1939. N. F. AGNEW REMOTE CONTROLLING APPARATUS Filed May 12, 1930 5 Sheets-Sheet 2 QMRM N. F. AGNEW 2,179,311 REMOTE CONTROLLING APPARATUS Filed May l2, 1930 3 Sheets-Sheet 3 v m w M m m W W mam n R J M A? gm VI IWm m M M NMM /1.|. Q Em .vmab F LJW .U Q AN 1% SN fim A SQ? u wk w w E Nov. 7, 1939.

F I n V KIIL w wmw R AW N5 5% MW Patented Nov. 7, 1939 PATENT OFFICE 2,179,311 REMOTE CONTROLLING APPARATUS Norman F. Agnew, Stockton, Calif., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application May 12, 1930, Serial No. 451,668

70 Claims.

My invention relates to remote controlling apparatus of the type comprising means for controlling from one point a selected device at a remote point, and for also indicating atsaid one point the condition of such device. Apparatus embodying my invention is particularly suitable for, though in no way limited to, use in a system of centralized traflic control for railroads providing for the control and indication of rail- Way traffic governing devices, such as switches and signals, from a control station, such as a dispatchers office.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 and 2,

when placed end to end with Fig. 1 on the left,

form a diagrammatic view showing one form of remote controlling apparatus embodying my invention. f Fig. 3 is a diagrammatic view showing a modified form of part of the apparatus shown in Fig. land also embodying my invention. Fig.

4 is a detail view illustrating the circuit for controlln-g the track repeater relay ITP shown in Fig. 2.. Fig. 5 is a detail. view showing the control circuit for the switch indication relay IKR 1 illustrated in Fig. 2. Figs. 6 and 7 are diagram- I for controlling and indicating movable devices located at a plurality of other points, such for example as, signal locations or stations distributed along a stretch of track. As here shown, Fig. 2 illustrates the apparatus located at one station and Fig. 1 illustrates so much of the oifice equipment asis necessary to cooperate with the equipment located at the station shown on Fig. 2. It will be understood, of course, that certain obvious duplications would be made in the oflice 9 equipment, as indicated in the drawings, to accommodate the system to additional stations similar to that shown on Fig. 2.

The apparatus at the station which is controlled. from the office may be of any suitable form, and for purposes of illustration, I have here shown a section of railway track w-b provided with a track circuit including a battery d and a track relay lTR. The section .ctb contains a switch e of the usual form. leading into a siding f. Westbound trafiic, that is, traflic moving from right to left, as shown in the drawings, is governed by two signals IRB and IRA, and eastbound trafiic is controlled by two similar signals ILA and ILB. As here shown, signals ILA and ILB are mounted upon the same mast and this mast also carries a call-on arm IC. Adjacent the left-hand end of section a-b is an approach section of track h--a provided with a track circuit including a battery it and an approach track relay IAR.

The switches, signals, etc., at the station may be controlled in any suitable manner by means forming no part of my present invention. For purposes of illustration, I will assume that the apparatus at the station is controlled by means similar to that disclosed in an application for Letters Patent of the United States, Serial No. 373,675, filed June 25, 1929, by Lloyd V. Lewis, for Remote controlling apparatus, now Patent No, 2,127,691, granted August 23, 1938. For accomplishing this control, the station is provided with a track repeater relay ITP which is energized only when the track relay ITR is energized, andwith a switch indication relay IKR which is energized in its normal (left-hand) position or its reverse (right-hand) position according as switch e occupies its normal or its reverse posi tion. As shown in Fig. 4, relay ITP is controlled by front contact I15 of track relay ITR, so that relay ITP is energized only when relay ITR is picked up. The switch indication relay IKR may be controlled, as shown in Fig. 5, by pole changer contacts I16 andI'I'I operated by the switch e, in such manner that the relay is supplied with current of one polarity or the other according as the switch occupies one extreme position or the other. .The reference characters INWS and IRWS designate switch control relays which operate, through the medium. of circuits not shown in the drawings, to move switch 6 to its normal position when relay INWS is energized and to its reverse position when relay IRWS is energized. Relays ILHS and IRI-IS are signal control relays which control signals associated with section ab in such manner that when relay ILHS is energized, signal ILA or ILB indicates proceed, according as switch e is normal or reverse, provided the track relay ITR is energized. In similar manner, when relay IRHS is energized, signal IRB or signal IRA indicates proceed, according as switch e is reverse or normal, provided the track relay ITR is energized. In addition, a relay IRI-I is energized when either of signals IRB or IRA indicates proceed, and a relay ILH is energized when either of signals ILA or ILB indicates proceed. Fig. 6 shows how relay ILH may be controlled by circuit controllers I18 and I19 operated by signals ILB and ILA, respectively, and Fig. '7 shows relay IRI-I controlled by circuit controllers I80 and IBI operated by signals [RB and IRA, respectively. The call-on arm IC is controlled by relay ICI-IS in such manner that when the relay ICI-IS is energized, the call-on arm is cleared.

Of the relays described in the foregoing paragraph, relays ITP, IKR, IIWVS, ERWS, IRI-I and ILH correspond exactly to the relays having similar reference characters in the Lewis application mentioned above. The remaining relays are controlled in accordance with usual and well,

known railway signaling practice, and the operation of the relays will be understood Without further explanation.

For the purpose of controlling the apparatus located at the station, there is located at the office a switch control lever Ip, a signal control lever la, and a call-on lever I7 for each station. As shown in Fig. 1, these parts are distributed to simplify the wiring diagram but in actual practice, all control levers for one station would be grouped together on a single panel which would also carry the indication lamps which will be described hereinafter and which are controlled from the corresponding station.

In general, my invention provides a synchronous selector comprising a chain of counting relays PI, Pia, P2, 19%, etc., located at the Offi0 and arranged to be energized in succession as the controlling and indicating functions proceed. I also provide a second synchronous selector comprising another chain of counting relays which operate in synchronism, with the counting chain at the ofiice, but this second chain is distributed throughout the system, certain relays being located at each station so that the stations as units are operated successively in synchronism with the chain of counting relays at the office.

For accomplishing the purposes described above, I provide line wires between the oflice and the several stations. Line wire I is a common return wire and is connected at the office and at each station with the common terminals C of all control circuits at the corresponding location. In addition, the office is provided with two sources of current of different characteristics. As here shown, these sources are batteries 5 and B which are oppositely connected with the common wire I so that the terminals B and N of these batteries, when connected through a conductor with terminal C, deliver to the conductor, currents of opposite polarities. In similar manner, other batteries 5 and 6 are connected with line wire I at the station and their terminals LB and LN may be connected with the circuits shown at the station to provide currents of opposite polarities.

The apparatus also comprises a line wire 2 extending from the office to each of the stations and serving as a stick wire controlling a supplemental selector performing certain functions which will be described in detail hereinafter. In addition to the two wires I and 2, a suitable number of wires are provided for accomplishing the transmission of the control and indication impulses between the oflice and the stations, and for controlling the step-by-step operation of the synchronous selectors. The number of these additional wires may be varied to meet special conditions, but for purposes of illustration I have shown two wires comprising a stepping wire 3 and a message wire 4 for this purpose.

Before describing the operation of the apparatus, it should be pointed out that, as shown in the drawings, lever I 7' occupies the position in which the call-on arm indicates stop; lever Ip occupies the position in which the switch con-- trolled thereby at the station occupies its normal position; and the signal lever lq occupies the position for which an eastbound signal determined by the position of the switch, in this case ILA, indicates proceed.

At the station, the switch e occupies its normal position, signal ILA indicates proceed and all of the remaining signals indicate stop. Relay ILI-I is therefore energized. The approach relay IAR and track relay I TR are both energized so that the track repeater relay ITP is also energized. Relay INWS is energized and relay ILHS is also energized as will be described hereinafter. The spnchronous selectors are normally at rest in a zero position, as shown.

I will now assume that the operator at the office wishes to restore to stop, signal ILA at the station shown in Fig. 2. In order to accomplish this result, he moves the signal control lever lg to its middle position, in which both contacts controlled by arm I of this lever are open, and he then reverses a manually operable starting key W. When this happens, current flows from terminal B, through contact 8-8 of key W, back contact 9 of a relay KP, and winding of a relay RI to terminal C. Relay RI therefore becomes energized. At the same time a circuit is completed for a relay OH from terminal B, over contact I IIIl of key W, and winding of relay OH to terminal C. When relay OH becomes energized, a stick circuit is completed for this relay over its own front contact I I, and over a back contact I2 of the last relay in the counting chain of relays PI, PI a, P2, etc., at the ofiice. The purpose of relay OH will be apparent as the description proceeds, but at the present juncture, this relay has no function.

When relay RI becomes energized, a circuit is completed for the first relay PI in the counting chain at the office. This circuit may be traced from terminal B, over front contact 13 of relay RI, back contact I 4 of a relay K, back contact I5 of relay KP and winding of counting relay Pl to terminal C. Relay PI therefore becomes energized.

The operator may now restore key W to the position in which it is shown in the drawings. When this happens, the circuit previously traced for relay RI is interrupted, so that the relay is deenergized. When contact i il of key W is closed, however, a circuit is completed for relay K from terminal B, over contact 88 of key W, front contact I6 of relay PI, and winding of relay K to terminal C. When relay K picks up it closes at front contact I! thereon, the circuit for relay KP. Relays K and KP are somewhat slow releasing and as will be explained hereinafter, maintain their front contacts closed until the expiration of a complete operation of the equipment. The energization of relay K also completes a stick circuit for relay PI, which passes from terminal B, over front contact I8 of relay K, back contact I9 of relay PIa, front contact 20 of relay PI, and winding of relay PI to terminal C. Relay PI therefore remains energized until relay PIa, which is the next relay in the counting chain, becomes energized.

Another result of this energization of relay K is that when its front contact 2I closes, terminal B at the oifice is connected with line wire 2. This line Wire is connected over back contact 22 of a relay SI at the station nearest the office with the winding of relay DI and it follows that when relay K at the office becomes energized, relay DI at the station picks up.

When relay DI at the station becomes energized the apparatus is in condition for-the transmission of the first control impulse. As here shown current of one polarity or the other is supplied, during this impulse, to the stepping line wire 3 at the office in accordance with the position of the switch control lever lp, and under the conditions here assumed this control circuit may be traced from terminal B at the oflice, through arm 23 operated by lever In, front contact 24 of relay Pl, winding of relay OT, back contact 25 of relay RI, line wire 3, front contact 26 of relay DI at the station, back contact 21 of relay SI, and winding of relay IWR to terminal C, It will be plain, therefore, that relays OT and IWR, become energized in series and the polarity of the current thus supplied to these relays iscontrolled by the position of the switch control lever lp. Since lp occupies its normal position, relay IWR becomes energized in the normal direction so that its polar contact 28 is swung to the left. i

l The closing of front contact 30 of relay IWR supplies current over back contact 3| of relay SE to the winding of relay SI, which thereupon becomes energized and is therefore stuck up over its own front contact 3| and line wire 2, which line wire we have previously explained is supplied with energy over front contact 2! of relay K at the office. When relay SI becomes energized, the circuit previously traced for relay Dl is interrupted but relay DI is held energized over back contact 32 of relay TI and front contact 22 of relay Sl, as will be apparent from the drawings.

It will be noted that the energization of relay SI interrupts the pick-up circuit previously traced for relay IWR at back contact 21 of relay SI. Relay IWR is held energized, however, be cause its front contact 5| is closed and this contact provides a shunt around back contact 27 of relay SI.

When relay IWR becomes energized, the c1osing of front contact 29 of this relay completes a circuit for relay IWP and the latter relay becomes energized.

When relay l WP becomes energized, the opening of back contact 33 of. this relay interrupts the stick circuit previously existing for relay INWS and passing from terminal LB, over back contact 33 of relay l WP, front contact 34 of relay lNWS and winding of relay INWS to terminal C. The interruption of this stick circuit does not deenergize relay iNWS, however, because another circuit is now closed for this relay including front contact 33 of relay IWP and normal contact 28 of relay IWR, as Willbe obvious from the drawings. Relays INWS therefore remains energized and when relay IWP next becomes deenergized, the stick circuit for relay INWS is restored. The switch e at the station therefore remains in its normal position,

When relays DI and IWR at the station close their front contacts, relay IE is connected with the message line wire 4, but this wire is connected, at the office, through front contact 46 of relay Pl, with the arms 1 of signal lever lq. Since the lever Iq occupies its middle position, no current is supplied to the line wire 4 under these conditions and relay IHC remains open. The

opening of back contact 31 of relay IWP, how

ever, interrupts the stick circuit previously existing for relay ILHS through the latter relays front contact 38 and since the pick-up circuit for relay ILHS is open at front contact 39 of relay I HP, relay lLI-IS becomes de-energized} thereby restoring signal lLA to stop.

Reverting now to the equipment located at the ofiice, it will be remembered that relay OT becomes energized in series with relay IWR at the station during the first control impulse. When relay OT becomes energized a stick circuit is completed for relay K which maybe traced from terminal 13, over contact ii-8 of key W, front contact 39 of relay OT, front contact lfl of relay K and winding of relay K to terminal C. Relay K, and hence relay KP, therefore remain picked up. Furthermore, the energization of relay OT completes a pick-up circuit for relay PM from terminal 3, over front contact 18 of relay Ii, front contact ll of relay KP, front contact d2 of relay OT, front contact 63 of relay Pi and winding of relay Pia to ter'minal C. When relay Pla becomes energized, the opening of back contact ill thereon, interrupts the stick circuit for relay PI, and this relay opens its front contact 43 to break the pick-up circuit just traced for relay Pl a. Relay PM is held energized, however, over a stick circuit including front contact it of relay K, backcontact it of relay P2 and front contact 45 of relay Plan When relay Pl releases, the opening of its front contact 24 (shown adjacent lever lp) interrupts the control circuit including relays OT and lWR so that these relays become deenergized to terminate the first control impulse. It should be pointed out that this operation of relay Pl would also disconnect line wire t from its energy at lever Iq by the opening of front contact 46 of relay Pl, if the lever lq were in position to supply current to line wire t to give a proceed signal indication as will be described in detailhereinafter. When relays OT and IWR release, the station equipment steps to the next set of'relays, to prepare for the transmission of the second control impulse. This isdone by means of a circuit which picks up relay D2 and passes from terminal LB, over back contact 3813f relay lWR, front contact ll of relay Si, back contact -l8 of relay S2, and winding of relay D2 to terminal C. i

However, ,the second control impulse is not transmitted at this time, but the control and indication impulses alternate, and back contacts at and 36 of relay IWR which are now closed serve as transmitter contacts to initiate the first indication impulse. I l

Relay Tl at the station and relay Rl at the office are now energized in series over the stepping llne wire 3 to give at the office an indication of the condition of certain apparatus at the station and in the present instance the indication transmitted, under these conditions, is a track indication which informs the operator at the office concerning the condition of section a--b. Forthis purpose the indication circuit including relays Ti and El is supplied with current of one polarity or the other at the station according as relay UK is energized or deenergized. As shown in the drawings, relay lTK is deenergized because relay i'lTP is energized when the section (t o is unoccupied, and so the indication circuit may be traced from terminal LN at the station, over back contact it of relay lTK, winding of relay Tl, front contact t of relay Si, back con-' tact M of relay lWR, front contact 26 of relay Di, line wire 3, back contact 52 of relay Pl, front contact ti l of relay PM and winding of relay Rl to terminal C. The current thus supplied 00' relay Rl energizes this relay in its reverse direc-- tion so that the polar armature 54 of this relay is swung to the right. Under these conditions, the pick-up circuit for relay ORTI remains open, although front contact 55 of relay PM and front contact 56 of relay RI are closed. Relay ORTI therefore remains deenergized and lamp 5'! remains dark to indicate that the section at the corresponding station is unoccupied.

At the same time that the track indication is delivered over the stepping line wire 3, another indication is delivered over the message line wire 4. As here shown, the second indication is a switch indication, and current of one polarity or the other is supplied to line wire 4, depending upon the position of relay IKR, which it will be remembered responds to the position of switch e at the station. Since the switch is now normal, the switch indication circuit may be traced from terminal LB at the station through normal contact 58 of relay IKR, front contact 59 of relay IKR, winding of relay IWD, front contact 50 of relay SI, back contact 36 of relay IWR, front contact of relay DI, line wire I, front contact GI of relay PIa, back contact 62 of relay PI, and winding of relay R2 to terminal C. Relays IWD and R2 are energized in the normal direction so that the polar armatures of these relays are swung to the left. When relay R2 becomes onergized, a pick-up circuit is completed for relay ONWI, from terminal B, over front contact 63 of relay R2, normal contact 64 of relay R2, front contact 65 of relay PM and winding of relay ONWI to terminal C. When relay R2 next becomes deenergized, the pick-up circuit just traced is interrupted but the relay ONWI will be held in its energized condition over a stick circuit including back contact 66 of relay Fla and front contact 6'! of relay ONWI. Under these conditions, that is, with relay ONWI energized, current is supplied to an indication lamp 68, over front contact 69 of relay ONWI, thereby lighting the lamp to indicate that switch 6 at the station occupies its normal position.

The indication impulse transmitted over line 3 is also a stepping impulse, and when relay RI becomes energized, it closes a pick-up circuit for relay P2, from terminal B, over front contact I3 of relay RI, front contact I4 of relay KA, front contact ID of relay Pia, and winding of relay P2 to terminal C. Relay P2 therefore becomes energized, breaking the stick circuit for relay Plc and completing its own stick circuit through contact I8 of relay K, back contact ll of relay P211, and front contact 72 of relay P2.

It will be noted that if relay PIa should re lease before the indication impulse is terminated, the pick-up circuit previously traced for relay RI is opened at contact 54 of relay Pia, but relay R! would be held energized because its front contact 25 provides a shunt around contact 54.

At the station, when TI became energized, the stick circuit previously traced for relay DI was interrupted at back contact 32 of relay TI so that relay DI became deenergized. When relay DI releases, the circuits through relays TI and RI and through elays WW3 and R2 are opened to terminate the first indication impulse, and back contacts 26 and 35 of relay DI connect the line wire 3 with the next group of apparatus As here shown this next group is a part of th apparatus at the same station, but this arrang ment is not essential. In order to place the equipment in condition to receive the second control impulse, the operation of a supplementary selector relay IM at the station is required, which relay is energized by current delivered over a front contact of relay OH at the office, which it will be remembered was actuated by operation of the key W. The contact of relay OH which effects this result is numbered l3 and is located in the drawings immediately below the signal control lever iq. Relay PIa at the office releases shortly after the first indication impulse is termihated, and when relay PIa releases, the circuit for relay IM becomes closed. This circuit may be traced from terminal B, through front contact '53 of relay OH, front contact it of relay P2, back contact SI of relay Pia, line wire 4, back contact 35 of relay DI, front contact 1 5 of relay D2, back contact I6 of relay S2, and winding of relay iM to terminal C. Relay EM picks up and initiates the second control impulse by completing the circuit for relays OT and ECH which are energized in series over line wire 3, the polarity of the current supplied to this circuit being controlled by the position of the call-on lever i9. As shown in the drawings, this circuit may be traced from terminal B, over arm 'I'I controlled by lever Ii, front contact I8 of relay P2, back contact 79 of relay PIa, winding of relay OT, back contact 25 of relay RI, line wire 3, back contact 26 of relay DI, front contact 80 of relay D2, back contact 62 of relay S2, front contact 823 of relay IM, and winding of relay ECH to terminal C. Relay lCH therefore becomes energized, and the polarity of the current supplied to this relay is such that the polar armature is swung to the left. When relay ICH becomes energized, it picks up relay S2 over front contact 83 of relay iCH, and back contact 8 5 of relay S2. When relay S2 is energized, it completes a stick circuit by virtue of which it is subsequently held in its energized condition over its own front contact 64, front contact H of relay Si, and back contact 38 of relay IWR. It will be observed that the energization of relay S2 interrupts the pick-up circuit previously traced for relay ECH at back contact 8| of relay S2. Relay ICE-I is held energized, however, because its front contact 85 is closed and this contact provides a shunt around back contact 8! of relay S2.

When relay S2 becomes energized, the circuit previously traced for relay D2 is interrupted, but relay D2 is now held energized over back contact 86 and relay T2 and front contact Q8 of relay S2. Since relay ICE is energized in the normal direction so that its polar armature 8! is swung to the left, the circuit for relay iCl-IS remains open, and this relay remains deenergized so that the call-on arm I C at point a continues to display its stop indication.

The purpose of relay IM is to permit the apparatus to step forward to the next location automatically, since, as will be described hereinafter, the normal operation of the apparatus when initiated from an outside station is to operate only until that particular station has returned its indication. When operation is initiated at the oflice, however, it is usually desirable to step completely through the equipment so that indications are received of the condition of all apparatus controlled from the oflice. For this purpose, the relay OH is arranged to be energized when the key W is operated and to remain energized until the final counting relay has been operated.

When relay OT becomes energized by the second control impulse, as explained above, the circuit is again closed for relay K which insures that this relay will remain picked up. Furthermore, the energization of relay OT completes a pick-up circuit for relay P211 similar to the circuit previously traced. for relay Pla, as will be understood without tracing this circuit-in detail. When relay PZc becomes energizedythe opening of its back contact ll interrupts the stick circuit for relay Piso that relay P2 becomes'deenergized and releases; When this happens the opening of front contact 18 of relay P2-(ad jacent lever I7) and the opening 'of front contact M of relay P2 (adjacent lever lq) interrupt the control circuits previously described and terminates the second control impulse. Relays IlVI, [CH and 'OT then become deehergized. When relay ICH releases, it closes its back contact 83, thereby connectingterminal LB with line Wire 2A, extendingto "the next station and thus picking up the relay at that station which corresponds to relay Dl at the stationshown on Fig. 2. This operation, of course, preparesthe apparatus at this next station to receive the succeeding impulses in the same"manner"as described in connection with the station shown in Fig. 2. When relay 'lCH releases, it initiates the second indication impulse by"completing 'a circuit for relay T2 at the station and relay R! at the office in seriesjoverlin'e Wire'3.., The 'Ipolarity of the current supplied'to this circuitis' controlled in accordance with the condition of the approach section h'a, and as h'e're' shown is governed by relay lAK controlled bythe approach track relay IAR. As shown in the draw ings, relay lARis energized, so that relay 'IAK is deenergized and the circuit then closedpasses from terminal LN, through'back contact '88 of relay IAK, winding of relay T2, front contact 89' of relay S2, back contact 85 of relayl'CI-I', front contact80 of relay D2, back contact 26 of relay Di, back contact 90 of relayPZj frontcontact 9| of relay P2a, andwinding of relay R! to teriiiinal C. The polarity of the current suppued to this circuit is such that relay BI is energized to swing its polar. armatures to the rigl'it"so' that relay ORA! remains deenergized," even though front contact 56 of relay Rlan'd front contact92 of relay P2a becomes closed. Lamp 93 therefore remains darki to" indicate that {the approach section ha at the station is unoccupied. When relay Rl becomes energized, relay P 3at thefofiice is energized over front contact l3 of relayfR l front contact M of relayK and front contact Q4 of relay P2a. RelayP3 then picks up and is subsequentlystuck up over back contact 95 of re'lafi P311, while relay PZa becomes 'deenergized. Even if relay P20. releases, however, relay RI will be held energized over itsfront contact 25 and;

line wire 3, until the impulse is terminated by the release of the station relay D2 and the open-' ing of front contact 80 of that may;

As pointed out hereinbefore,all1signals at the station shown on Fig. 2 are at stop, so that relays IRI-I and lLH are both deenergized. ;As a result,

no circuit is completedfo r relayfRZ when the circuit previously traced for reIaysfIZ and RI. is: closed. As a result, no pick u'p circuit is closed for relay OLHI at the officeand since the stick circuit for this relay is interrupted at back conenergized,relay OLHl becomes deenergized to extinguish lamp 9?. Back contact!!! of relay OLHI and back contact 99 of relay ORHI "are then both closed, so that lamp lllll is lighted to indicate that all of the signals at thejstation indicate stop. l

i When relay-T2 became energized in series with relay Rl,the stick circuit forrelay D2 over back contact 86 of relay T2 was opened, so that relay D2 is'now deenergized and releases, terminating the impulse. When back contact 80 of relay D2 closes, the line wire 3 is completed to the next stationto the right of that shown on Fig. 2.

Theiirst control impulse for that station is initiated when relay P2a closes its back contact in the circuit for relay OT, and the operation at this station will be understood from the previous discussion of the apparatus shown on Fig. 2.

All of the remaining stations operate in succession in a similar manner until the last station has been controlled and has indicated its condition to the office. When this happens, the final counting relay at the oifice becomes energized, thereby opening its back contact 12 and breaking the stick circuit for relay OH at the ofiice. Relay Ol-I then releases and since front contact 13 of relay OH is then open, no control circuit'is closed to energize relay OT. The slow release relays K and Kp then become deenergized and release successively, and when relay K releases, it deenergizes relay Si. The release of relay SI deenergizes relay S2 and all corresponding relays are deener'gized in succession so that the apparatus is restored to its normal condition.

It will be plain from the foregoing that if the key W at the office is operated, the equipment is set into operation to transmit a series of stepping impulses which serve alternately as control and indication impulses to condition all of the devices at the several stations in succession in accordance With'the positions of the control levers corresponding thereto at the office, and also toindicate at the oflice the condition of the several devices. This is performed by sending out a firstcontrol impulse from the office to a first station, then sending an indication impulse from that station, then sending another control impulsefrom the oihce and another indication impulse from the station, then stepping to the next station, and repeating this process until all stations inorder have been controlled and have indicated.

It should be pointed out also that if the control levers at the office occupy different positions from those previously assumed, the actual control at the station may be different, although the general plan of operation remains the same. For example, I will assume that the signal control lever lq is moved to its RI-If? position so that arm 7 engages the contact connected with terminal N. Under these conditions,.when relay IWR at the station shown on Fig. "2, becomes energized, relay lI-IC at the station is energized during the first control impulse to swing its polar armature to the right. Relay I WP will be energize'd under these circumstances, and a circuit is then completed, over front contact .31 of relay IWP, and front contact l0! of relay IHC to energize'relay IHP. Relay IHP is subsequently stuck up over its own front contact I02 and front contact 3l of relay IWP. .Since relay IHC is energized in its reverse direction so that polar armaturelllii is swung to the right, current is supplied to relay IRHS over front contact 39 of relay lI lP and reverse contact I03 of relay IHC. Relay IRHS then becomes energized, and is subsequently stuck up over its own front contact I04 and back contact 3'! of relay IWP after the latter relay becomes deenergized. Since relay l Rl-I Sis energized, signal. IE3 or lRAindicates proceed, depending upon the position of switch 6.

In the present instance, since switch 6 is normal, signal IRA would be moved to the proceed position.

In similar manner, if signal control lever lq is restored to the position in which it is shown in the drawings so that arm I engages the contact connected with terminal B, and the apparatus is then set into operation, relay IHC will be energized during the first control impulse to swing its polar armature to the left when relay D! becomes energized. When this happens, relay IE? will become energized, as explained hereinbefore, and a pick-up circuit will then be closed for relay ILHS over front contact 39 of relay IHP and normal contact I83 of relay IHC. Relay ILHS then becomes energized and is subsequently stuck up after relay IWP becomes deenergized, over back contact 31 of relay I WP and front contact 38 of relay lLHS. When relay ILHS is energized, signal ILB or ILA indicates proceed, depending upon the position of switch e, and as here shown, with switch e normal, signal ILA indicates proceed.

Similarly, I will assume that switch control lever ip occupies its reverse position, so that arm 23 engages the contact connected with terminal N. If the apparatus is now set into operation to control and indicate the several stations, when relays OT and IWR become energized after relay DI becomes energized, the polarity of the current supplied to relay IWR swings the polar contact 28 of this relay to the right. When relay IWP becomes energized, current is then supplied over front contact 33 of relay IWP, reverse contact 28 of relay IWR, and winding of relay IRWS to terminal C. When relay IWP next becomes deenergized, a stick circuit is completed for relay IRWS, over back contact 33 of relay IWP and front contact I of relay IRWS. When relay IRWS is energized, the switch 6 is operated to its reverse position.

The switch, may of course, be restored to its normal position by restoring the lever Ip to its normal position in which it is shown in the drawings and operating the key W, under which conditions, the apparatus will operate as previously described to pick-up a stick relay INWS and restore the switch to its normal position.

The call-on lever I9 is customarily employed to clear a call-on arm, such as IC, of a signal located at point a on Fig. 2 when the proper controls are set up to clear one of the signals, such as ILA or ILR, but when such signal is prevented from assuming its proceed position by some dangerous condition such as the presence of a train in section ab. For example, I will assume that the lever Iq occupies its LH position, as shown in the drawings, so that relays IHS and ILH at the station are energized, but that because of a train in section ab', the signal ILA is prevented from clearing. If, now, the operator at the oiiice moves lever I9 to the right, connecting arm 'Il attached to terminal N, he may cause the call-on arm I C at the station to indicate proceed. This is accomplished as follows: When relay OT at the o-fiice and relay ICH at the station become energized in series during the second control impulse following the energization of relays D2 and I M, the current supplied to the circuit including relay ICE is of such polarity that relay ICI-I swings its polar contact 8'I to the right. When this happens, a circuit is closed from terminal LB, over contact 8'! of relay ICH, winding of relay ICHS, front contact I06 of relay ILHS to terminal C. Relay ICHS then becomes energized and clears signal IC by means forming no part of my present invention.

In the previous discussion I have assumed that the apparatus is set into operation by manipulation of the key W at the omce. The operation can also be started automatically in response to any change in the condition of a movable device at any station. In explaining this feature of my invention, I will first assume that with the apparatus in the condition shown in the drawings, a train enters section ab at the station shown on Fig. 2. When this happens, relay ITR becomes deenergized. The opening of front contact I15 of relay ITR breaks the circuit for relay ITP (see Fig. 4), and the latter relay then becomes deenergized. When relay ITP becomes deenergized, a pick-up circuit is completed from terminal LB, over back contact I01 of relay ITP, back contact I 08 of relay DI, and winding of relay ITK to terminal C. Relay ITK then becomes energized and is subsequently held energized to store the track-occupied indication until transmitted, over a stick circuit which may be traced from terminal LB, over front contact I09 of relay ITK, back contact H6 of relay ITD, and winding of relay ITK to terminal C. When relay ITK becomes energized, a preliminary or starting circuit is closed for relay RI at the oflice, which circuit originates at the station and may be traced from terminal LB, over front contact III of relay ITK, back contact II2 of relay ITD, back contact II3 of relay SI, back contact 26 of relay DI, line wire 3, back contact I I4 of relay K, back contact 9 of relay KP, and winding of relay RI to terminal C. Relay Rl at the ofiice then becomes energized, picking up relays PI and K as explained hereinbefore. When relay K becomes energized, a stick circuit is closed for relay PI, and relay DI at the station shown on Fig. 2 becomes energized. The circuit for relay BI is opened at back contact 26 of relay DI, and relay Ri releases, completing the circuit for the first control impulse through relays OT and IWR. From this point on, the operation of the equipment is the same as that described hereinbefore, except that when relays RI and TI become energized in series, the circuit now includes front contact 49 of relay ITK, so that the polarity of the current supplied to the circuit is such as to energize relay RI in the normal direction to swing its polar contacts to the left. At the time relay RI becomes energized, relay PIa is also energized so that a circuit is completed from terminal B, over front contact 56 of relay RI, normal contact 5d of, relay RI, front contact 55 of relay Pia, and winding of relay ORTI to terminal C. When relay PIa next becomes deenergized a stick circuit is completed for relay ORTI, over back contact I I4 of relay PIa, and front contact II5 of relay ORTI. Front contact II 6 of relay ORTI is thereby held closed to light lamp 5'! and indicate that the section a-b at the station is occupied by a train.

Furthermore, when relay TI becomes energized, a pick-up circuit is completed for relay ITD, from terminal LB, through front contact II 1 of relay DI, front contact I I8 of relay Tl, front contact II9 of relay ITK and winding of relay ITD to terminal C. Relay ITD then becomes energized, and is subsequently stuck up after the deenergization of relay TI over front contact I20 of relay ITD and back contact 320, of relay TI. It should be noted that when relay ITD becomes energized, it opens, at back contact lIll thereon, the stick circuit previously traced for relay ITK, but relay ITK is now held up over atemporary stick circuit including its own frontcontact I39 and front contact IE8 of relay DI, When relay DI becomes deenergized, this temporary stick circuit is interrupted, but relay lTK is subsequently held up as long as relay I'IP is deenergized, over back contact Ill'l of relay ITP. Underthese conditions, then, relays E'I'Kand ITD are both energized so that the starting circuit through back contact H3 of relay S I is open If now the train passes out of section ca -b, relay ITP again becomes energized, thereby deenergizing relay ITK and again completing the starting circuit over back contact III of relay ITK and front. contact II2 of relay ITD. Under these conditions, the apparatus is again set into operation, but when relays TI and RI are energized in series, the circuit will include back contact. l?! of relay ITK, so that relay RI will be energized in the reverse direction. Under these conditions, the opening of back contact I l d of relay Plainterrupts the stick circuit for relay ORTI, and .since the pick-up circuit for this relay is openat normal contact 54 of relay RI, relay ORTI remains deenergized and lamp 5'! is extinguished to indicate that the train has left the corresponding tracksection. Furthermore, when relay Tl becomes energized, the stick circuit for relay ITD is interrupted at back contact 32a. of relay TI, so that relays ITK and ITD are now both deenergized and the other starting circuit controlled thereby, is open.

The; apparatus may be set into operation also by any change in the position of the switch 8 which will be reflected in. the position of the switch indication relay IKR. For example, I will assume that with the parts occupying the positions in which theyare shown in the drawings, relay IKE becomes energized in its reverse position to swing its polar contacts to the right.

Whenthis happens, a circuit is completed from terminal LB, over front contact I2I of relay IKR, polar contact I22 of relay IKR, polar contact I23 of relay IWD, back contact, I I3 of relay SI, back contact 2 .5 of relay DI, and thence over line wire 3 to the office, as described hereinbefo-re. The starting circuit. thus closed sets the apparatus into operation in the manner previously described. ,When relays IWD and R2 are energized in series, following energization of relays DI and SI and deenergization of relay IWR during the first indication impulse, the polarity of the current supplied to thecircuit is such that relay Rfibecomes energized in the reverse'd hection toswing its polar contact 63 to the right. When this happens, a pick-up circuitis completed over front contact 63 of relay R2, reverse contact fi l of ,relay R2, front contact I24 of r'elayPIa and winding of relay ORWI to terminal C. Relay, ORWI then becomes energized, and whenirelay PIa again decomes deenergized, relayORW! is stuckup over its own frontcontact I25 and back contact 66 of relay PIa In the r'rieantime, relay ORWI has been energized and since relay ORWI is now energized, current is supplied over its front contact I26 to light lam till, thereby indicating that the switch a on Fig. 2, occupies its reverse position. Furthermore, thecurrent supplied .to the circuit including relays IWD and R2also swings the polar armature IE3 of relay IWD to the right into coincidence with the polararmatures of relay IKR, thereby breaking the starting circuit previously described. If, now, the switch e is restored to its normal position, relay IKR is again operated out of agreement with relay IWD and a starting circuit is closed to set the apparatus into operation. Under these conditions, the indicationreceived at the office again energizes relay ONWI to light lamp 68 and deenergizes relay ORWI, to extinguish .lamp I2'I.

It should be pointed out that if for any reason the switch at the station occupies an intermediate positionso that relay IKR is deenergized, no current is supplied to the circuit when relays IWD and R2 are connected in series. As a result, relay R2 remains deenergized, while relay PIa picks up to break the stick circuit for either of the relays ONWI or ORWI thus extinguishing both of the lamps 68 and I2I to indicate that the switch e at the station shown on Fig. 2 occupies an intermediate position.

. The relays IAK and IAD are arranged to provide an approach indication, under the control of relayJIAR in the same manner as relays ITK and ITD provide a track indication under the control of relay ITR. Thus when relay IAR picks up or releases, a starting circuit is closed. when relays. IAK and IAD are out of agreement and the indication transmitted when relays T2 and RI are energized in series, is controlled by contact 88 of relay IAK to govern the polarity of the current supplied to the circuit and hence to determine whether or not relay ORAI at the office is energized to light lamp 93. This feature of my invention will immediately be apparent from the previous discussion of the reception of the track indication.

The apparatus is also constructed to complete the starting circuit and initiate operation of the equipment upon any change in signal indication. Any such change in signal indication picks up relay IHK, and when this happens, current flows from terminal LB, over front contact I28 of relay IHK, back contact I29 of relay S2, back contact 80 of relay D2, back contact 26 of relay DI, line wire 3 and thence as before to the apparatus at the canoe. When this starting circuit is closed, the operation of the equipment is initiated, and this operation continues in the same manner as when any other starting circuit is completed. Relay IHK is controlled by relays IRI-I and ILH' and also by a back lock relay IX. Relay IX is energized only when relays IRH and ILH are both denergized, but when the condition of either of relays IRI-I or ILH changes, relay IHK is energized for a brief interval over a pick-up circuit and is subsequently stuck up over its own front contact I30 and back contact I3I of relay S2 until the corresponding indication has been delivered. For example, as shown in the drawings, relay I RH is deenergized and relay ILH is energized, as would be the case when signal ILA indicates proceed. If, now, relay ILH becomes deenergized, as when signal ILA is restored to the stop position, a circuit is completed over back contact I32 of relay IRI-I and back contact I33 of relay ILH to relay IX, which then becomes energized. Before the relay IX opens its back contact, however, a pick-up circuit is completed from terminal LB, over contact I32 of relay IRH, back contact I33 of relay ILH, back contact I34 of relay IX, and winding of relay IHK to terminal C. Relay IHK is therefore energized and is subsequently held up over the stick circuit described hereinbefore. When relay IHK becomes energized, the closing of front contact I28 completes a starting circuit and sets the apparatus into operation. Since the office relay OH has not been energized, relay EM does not become energized and its contact 82 in the pick-up circuit for relay ICH remains open. This contact, however, is now bridged by contact Hit of relay HI and relay ICH picks up in response to the second control impulse, as previously described. Relay lCH energizes relay 82 which picks up and opens its back contact .I3I in the stick circuit for relay IHK. Relay IHK therefore releases so that the starting circuit will remain open after the apparatus completes its operation. Since relays ILH and IRH are both deenergized, there will be no signal indication impulse transmitted over line 4 when relay ICH becomes deenergized and relays OLHI and ORHE at the ofiice both become deenergized to light lamp its.

' With the apparatus in its normal condition, as shown, if relay lRI-I becomes energized, as would be the case if signal IRA or iRB is caused to indicate proceed, the circuit for relay IX would be broken, but beforethe latter relay could open its front contacts, a pick-up circuit would be closed for relay lHK over front contact I32 of relay HRH, front contact I35 of relay 5X and winding of relay IHK to terminal C. The energization of relay IHK would close the starting circuit as before to start the system into operation. Since relay lRH is now energized, however, the indication circuit is completed when relay I OH becomes deenergized while relay S2 is energized, and current flows from terminal LN, over front contact E36 of relay IRH, front contact iii? of relay back contact of relay I CH, front contact it of relay D2, back contact 35 of relay Di, line wire 4, front contact I39 of relay P2a, back contact Mi) of relay P2, and winding of relay R2 to terminal C. The polarity of the current supplied to this circuit is such that relay R2 swings itspolar contact 6 to the right and current then flows from terminal B at the office, over front-contact 53 of relay R2, reverse contact 64 of relay R2, front contact ml of relay PM and winding of relay ORI-II to terminal C. Relay ORHl then becomes energized and is subsequently stuck up over back contact 96 of relay Pia and front contact I42 of relay ORHI. As a result, lamp M3 is lighted over front contact EM, of relay ORHI to indicate that a westbound signal at the associated station indicates proceed.

The operation of the apparatus when relay ILH becomes energized is similar to that just described for the energization of relay IRH, except that the circuit for relay R2 then includes front contact 565 of relay lLH instead of front contact I35 of relay iRH. The polarity of the current supplied to relay R2 is thus reversed so that relay OLI-Il becomes energized and is stuck up over a back contact of relay P20. to light lamp 9! and indicate that an eastbound signal indicates proceed at the associated station.

There is one major difference between the op eration of the apparatus when started at the office and the operation of the apparatus when started by a change in indication at the station. As shown in Figs. 1 and 2, when started at the ofiice by operation of key W, the equipment steps through all of the stations in succession until the final counting relay has been operated.

As illustrated in Figs. 1 and 2, when the operation is initiated from a station, the equip ment operates until that particular station has been reached, whereupon the apparatus stops and returns to its normal condition. To illustrate this feature, I will assume that a track indication from the station, shown in Fig. 2, is initiated by the deenergization of relay ITP. The system then operates as previously described until the circuit over which relays RI and TI are energized in series is interrupted. After this happens, the next step in the sequence of operations must be the energization of relay ICH over line wire 3. It will be apparent, however, that the circuit through relay iCH is open at front contact 82 of relay [M and also at front contact I46 of relay Hi. Since this control circuit can not be completed, relay OT at the ofiice remains deenergized, whereupon relays K and KP become deenergized, relays SI and S2 become deenergized, and the apparatus is returned to its normal condition.

It should be observed, however, that when any starting circuit is closed at a station, current is supplied from terminal LB to the line wire 3 at that station. At any location between this station and the office, a relay corresponding to relay HI on Fig. 2, will be energized to permit the equipment to step out as far as the station at which the indication originated. For example, if a station to the right of the apparatus, shown on Fig. 2, has initiated an indication, the line wire 3A will be connected with a source of current so that when relay D2 becomes energized, current flows from terminal LB of the source over this line wire 3A, over front contact I41 of relay D2 and back contact I48 of relay HI through the winding of relay HI to terminal C. Relay HI then becomes energized, and a stick circuit for the relay is completed from terminal LB, over front contact Hi9 of relay D2 and front contact MS of relay HI, through the winding of relay HI to terminal C. Under these conditions, it will be seen that front contact Ms of relay HI is closed ranged the apparatus in such manner that when I the operation is started from the ofiice the equipment functions only until the selected station which it is desired to control has been reached, and then the apparatus returns to its normal condition. single key W of Fig. 1 with a plurality of starting keys OWI, 0W2, 0W3, etc., one for each panel at the office. Furthermore, the relay OH of Fig. 1 is replaced by a plurality of relays OHI, 0H2, OHS, etc, one controlled by each starting key. With this arrangement the contact 73 of relay OH shown in Fig. l which operates to step from station to station when the operation is initiated at the office is replaced by front contacts 201, 202,

etc., of relays OHI, 0H2, 0H3 respectively. If key OWl is operated to actuate the equipment only up to the corresponding station, the starting circuit for relay RI is closed over contact 2M and the system set into operation in the same manner as previously described in connection with Fig. 1'. At the same time, the operation of contact 205 of key OWI completes a pick-up circuit for relay OHI, which becomes energized, and is thereafter stuck up over its own front con- This is accomplished by replacing the tact M6 and back. contact 2b! of relay Pia; after the keyOWl is released.

Now at the timethat the second control impulse is sent to the station corresponding to key OWE (in case the station illustrated on Fig. 2), relay P2 is energized. Since relay OHl is now energized, current is supplied to line wire t at the ofiice over front contact 20E of relay OI-Ii and front contact of relay P2 to energize relay lM, consequently the second control. impulse is received by relay NIH and subsequently the equipment steps to the next station. But, at the termination of the second impulse,relay OT picks up and energizes relay P20. as described herein before. When relay PM picks up, the stick circuit for relay Olii is interrupted, and the latter relay becomes deonergized. Line wire t can not thereafter again be supplied with current for stepping from stationto station unless another relay controlled by another starting key is energized, the apparatus therefore drops out and restores to normal after the transmission of the first indication impulse from the next station.

With the modification shown in Fig. 3, there fore, the system operates fully only as far as the station which is selected by the starting key which. is operated, and thus materially decreases the average time in which the lineisinuse for delivering control. codes. l i

It should be pointed out that the control of the supply of current to line wire t by the relays OI-ll, H2, etc, is not essential, as these relays could be utilized togovern any control or indication circuit for the corresponding panel, which is required to be operatedto step from station to station.

It will be observed that in some instances a circuit is controlled by both the frontand back contacts of a relay. If it is desirable that the cirhave shown rectifiers connectedbetween one terminal of a relay and the terminal 0. These rectifiers are utilized to shunt the current induced in the relay windings when the relay circuit is opened and tend to make the relays slightly slow releasing and also reduces sparking at the contacts which open the relay circuits.

I have also illustrated a resistor its and a condenser iii! connectedin series across front contact Eli of relay Di to reduce sparking at this contact, and a similar arrangement is also provided for front contact ill of relay D2.

One advantage of apparatus embodyingmy invention is that every station is provided with apparatus which isidentical with the apparatus located at every other station, irrespective of the total number of stations in the system. That is to say, in order to increase the number of stations controlled from a single ofiice, all that is necessary is to extend the four line wires l, 3 and to the stations which are to be controlled, install at each ofsuch stations, apparatus similar to that. shown on Fig. 2, and add to the counting chain at the oflice, addi tional relays similar to relays Pl, Pia, etc, to

accommodate for the increased number of steps involved in complete operation of the system.

Another advantage of apparatus embodying my invention is that the system functions in precisely the same way whether started from the Offl0 or from a station and the system must operate in the manner intended so that control impulses and indication impulses alternate on the line wires, connecting the stations successively with the office and if the parts do not function in the proper sequence, the apparatus will drop out and start over from the beginning.

Another advantage of apparatus embodying my invention is that since local batteries are utilized at each station, comparatively small voltages may be employed satisfactorily. Excessive voltages are not required, because it will be noted that under no conditions are more than two relays connected in series in the same circuit. It should be also pointed out that one complete operation of the system. controls and indicates all functions. This feature is particularly valuable where the time involved making changes in the condition of the devices controlled by the office levers is of primary importance.

With my invention, the. conditions of all devices may be changed during a single operation of the equipment and in the same time as would be required to change the condition of a single device.

Another advantage of my invention is that since the line circuits are in every instance opened at the location where energy is supplied to these circuits, that is, adjacent the battery source, it is unlikely that a faulty contact or imperfect insulation would. result in a leakage current to hold-up a relay which should be deeriergized, thereby interfering with the proper operation of the system.

Finally, it will be noted that since the line circuits are sectionalized, in case any failure occurs at one of the stations, the system will still operate satisfactorily between the oflice and the station at which the fault occurs. One advantage of this feature is that it assists in discovering the location of the failure because it indi cates, by the failure of the system beyond the point of failurathe point at which the fault occurs. Another advantage of this feature is that the complete equipment is not thrown out of service by this fault but all parts of the system between the location at which the fault occurs and the office can be operated at full efficiency.

As suggested above, the complete wire circuits here shown, may be replaced by circuits each including one wire and a ground return, and it should be understood that in the following claims, the terms line circuit, line wire, etc. are intended to include circuits with ground return aswell as complete metallic circuits.

Although I have herein shown and described only two forms of remote controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of invention.

Having thus described my invention, What I claim is:

1. A centralized tramc controlling system for railroads comprising an ethos having a plurality of controlling devices, a first series of counting relays one for. each controlling device, a plurality of control relays distributed at spaced points, a second series of relays one adjacent each said control relay, means for transmitting impulses alternately from said office and said points in sequence, and means responsive to said impulses for operating the relays of said two series in order and in synchronism and effective when each relay of said first series is operated to condition the control relay associated with the corresponding relay of the second series in accordance with the condition of the controlling device associated with the relay of the first series which is operated;

2. In combination, a line circuit, a series of counting relays, a plurality of movable devices, an indication relay, means for operating said counting relays in order, means effective when each of said counting relays is operated to supply said indication relay with current under the control of a different one of said movable devices over said line circuit, and a plurality of other relays each controlled by said indication relay when a corresponding counting relay is operated.

3. Remote controlling apparatus comprising a plurality of station relays, a line circuit normally including a contact of each said station relay, a plurality of movable devices one for each station relay, means for operating said station relays in succession, an auxiliary relay associated with each said station relay and each arranged to be included in said line circuit when the associated station relay is operated, and means operating when each station relay is operated to supply said line circuit with current under the control of an associated one of said movable devices for governing the auxiliary relay then connected with the line circuit.

4. Remote controlling apparatus comprising a line circuit, a plurality of control relays normally disconnected from said-line circuit but arranged at times to be connected with said line circuit in succession, a plurality of movable devices one for each said control relay, an additional relay, and means controlled by said additional relay and operating when any of said control relays is con-' nected with said line circuit to supply said line circuit in series with said additional relay with current of a selected character depending upon the condition of the corresponding device, each control relay being responsive to the character of the current supplied thereto.

5. Remote controlling apparatus comprising a line circuit, a series of relays all normally disconnected from said line circuit, a plurality of mov able devices one for each relay of said series, means operating in response to a change in the position or" any such device to connect the first relay of said series with said line circuit, means for connecting each remaining relay of the series with said line circuit when the preceding relay in the series becomes energized, means operating when any relay or said series is connected with said line circuit to supply the line circuit in se ries with such relay with current of a selected character depending upon the position of the associated device, an auxiliary relay, means for connecting said auxiliary relay with said line circuit when any relay of said series is connected with the line circuit, and a plurality of indication devices selectively controlled by said auxil iary relay in accordance with the relay of said series which is operated and controlled in accordance with the character of the current supplied to said auxiliary relay.

6. Remote controlling apparatus comprising an oillce and a station connected by a line circuit, a plurality of movable levers at the ofiice, two relays RI and OT at the ofiice, a plurality of control relays at the station, a plurality of devices one controlled by each such control relay, a manually controlled starting key at the office, means set into operation when said key is actuated to supply said line circuit with current at said ofiice in series with relay OT under the control of one of said movable levers, means for connecting a control relay at the station with said line circuit when such circuit is supplied with current through relay OT, means efiective when said relay OT becomes energized for connecting relay R! with said line circuit, means efiective when said control relay becomes energized to supply said line circuit at the station with current under the control of one of said devices, means operating when relay RI becomes energized to supply the line circuit with current at the officc in series with relay OT under the control of a second one of said levers, means operating when relay OT is connected with the line circuit the second time for connecting a second control relay at the station with said line circuit, means operating after relay OT and said second control relay are energized to again supply relay R! with current over said line circuit under the control of a second device at said station, and a plurality of indicators successively controlled by relay RI,

7. Remote controlling apparatus comprising a line circuit, a holding circuit, a relay SI, a relay iWR, means for at times energizing relay lWR over said line circuit, means controlled by relay IWR for at times picking up relay SI, means for subsequently holding relay SI energized over said holding circuit, a relay S2, a relay ICI-I, means for at times energizing relay lCI-I over said line circuit, a pick-up circuit for relay S2 controlled by relay lCI-I, a stick circuit for relay S2 controlled by relays SI and IW'R, movable devices separately controlled by relays IWR and !CH, and indication means operated over said line circuit.

8. Remote controlling apparatus comprising a line circuit, a plurality of movable devices, a first relay responsive to the character of current supplied thereto, means for at times repeatedly operating said first relay over said line circuit each time by current of selected character depending upon the positions of a diilerent one of said devices, a chain of counting relays arranged to be operated in sequence by repeated operation of said first relay, and indication means controlled jointly by said first relay and by said counting relays.

9. Remote controlling apparatus comprising a line circuit, a plurality of movable levers and indication relays at one point, a plurality of control relays, a plurality of movable devices one controlled by each said control relay, and means for delivering to said line circuit a series of alternate control and indication impulses, each control impulse being of selected polarity governed by one of said movable levers for controlling an associated control relay and each indication impulse being of selected polarity governed by one of said devices to control an associated indication relay, and means responsive to each such impulse for preparing the apparatus to deliver the succeeding impulse in such series.

10. Remote controlling apparatus comprising a line wire connecting an ofiice and a station, manually controlled means for at times supplying a starting impulse to said line wire, means operating in response to said starting impulse to deliver a series of alternate control and. indication impulses to said line wire, means selectively controlled by said control and indication impulses, and automatic means at said station for at times delivering a starting impulse to said line wire. 11. In combination, a line wire connecting omce and a station, a movable device at said station, means operating in response to a change in the position of said device to deliver a starting impulse to said line wire, means at the ofiice responsive to said starting impulse to deliver an" other impulse to said line wire, means responsive to such other impulse for delivering to said line wire an indication impulse under the control of said device, and indication means at the oflioe selectively responsive to said indication impulse.

12. In combination, a first line wire connecting an oflice and a station,.a movable device at said station, means operating in response to a change in the position of said device to deliver a starting impulse tosaid first line wire, a second line Wire connecting said ofiice and station, means responsive to said starting impulse for delivering another impulse to said secondline wire, means at the station responsive to said other impulse to deliver to said first line wire an indicationimpulse under the control of said device, and means at the office selectively controlled by said indication impulse.

13. In combination, a first line wire connecting an office and a station, a movable device at said station, a normally deenergized relay Di at the station, means operating in response to a change in the position of said device to deliver a starting impulse to said first line wire over a back contact of relay Dl, a second line Wire connecting said oflice and station, means at the ofiicc responsive to said starting impulse for delivering another impulse to said second line wire, means responsive to said other impulse for energizing relay DI. means operating. when relay Di is energized to deliver an indication impulse to the first line wire under the control of said device, and means at the ofiice selectively controlled by said indication impulse. V

14. In combination with a line wire, a series of movable devices, means set into operation by a change in the position of. any device to deliver to the line wire an indication impulse under the control of the first device in said series, a plurality of indicators one for each said device, means responsive to each. indication impulse to condi tion the associated indicator in accordance with such impulse and to coect the line wire with means for delivering an indication impulse under the control of the next device in said. series, and means controlled by the last device in series which. has been operated to prevent the delivery of indication impulses by succeeding devices in said series.

15. In combination with a first line wire connecting an office and a plurality of stations, a series or movable devices at least one located at each station, a plurality of transmitting equipments one for each said device, means set into operation by a change in the position of any particular device for successively actuating the transmitting equipments for all. devices in said series up to and including the particular device, means operating when any transmitting equip ment is actuated to deliver to said line wire an indication impulse under the control or the corresponding device, and indication means at said ofiiceselectively controlled by said indication impulses.

16. In combination with a first line wire connesting an office and a plurality of stations, a series of movable devices at least one located at each station, a plurality of transmitting equipments one for each said device, means set into operation by a change in the position of any particular device for actuating the transmitting equipment associated with the device of said series, means operating when any transmitting equipment is operated to deliver to said line wire an indication impulse under the control of the corresponding device, indication means at the oilice selectively responsive to each indication impulse, and means controlled. by each transmitting equipment and operating when any such equipment preceding said device in said series is actuated to actuate the succeeding transmitting equipment.

17. In combination with a line circuit, a manually operable key, a relay Rl, a chain of counting relays, a relay K, a pick-up circuit for relay Rl arranged to be closed it said hey is while relay K is deenergized, a pick-up circuit for the first relay of said counting chain including a front contact of relay Rl, a pick-up circuit for relay is! arranged to be closed ii: key is re stored to its normal position while the first relay of said counting chain is energized, means operating when said relay K is energized to deliver successive spaced control impulses to said line circuit, means selectively responsive to said control impulses, means operating during the intervals between successive control impulses to deliver indication impulses to said line circuit, means responsive to successive indication i1npulses to energize successive relays in said counting chain, and indication means controlled by said counting. chain and selectively responsive to said indication impulses.

18. Remote controlling apparatus comprising a line circuit, a series of control relays, a plurality of starting keys, a plurality of control devices, one 'for each said control relay and each associated withone of said starting keys, means set into operation when any starting key is operated for successively connecting control relays of said series as far as the relay associated with such key with said line circuit, and means efiective when any control relay is connected with said line circuit to supply the line circuit with current under the control of the associated control device.

19. Rernote controlling apparatus comprising a line circuit, a series of control relays, aplurality of starting a plurality of control devices,

one for each said control relay and each assov ciated with one of said star keys, stepping means set into operation when any of said keys is operated for successively connectingthe control relays of said series with said line circuit, means operating when the control relay corresponding to the operated key has been connected with said line circuit to prevent further operation of said stepping means, and means operating when any control relay is connected with said line circuit to supply the line circuit with current under the control of the associated control device.

2i). Remote controlling comprising a line circuit, plurality 01" control relays, a pinrality'oi movable levers and tion. relays at one point, a plurality of starting keys one for each said lever, a plurality movable devices rol relay, .n by a move- (ill control impulse being governed by one of said levers for controlling an associated control relay and each indication impulse being governed by one of said devices for controlling an associated indication relay, stepping means responsive to each such impulse for '"reparing the apparatus to deliver the succeeding impulse in such series, and means operating if said automatic means was actuated by operating a starting key to prevent operation of said stepping means after the delivery of the control impulse governed by the corresponding lever, and means operating if said automatic means was actuated by a movement of one of said devices for preventing operation of said stepping means after the delivery of the indication impulse governed by such device.

21. In a remote control system, an office and a station connected by a line circuit, a plurality of devices at said station, control and indication means at said OI'fiCEZ for said devices, chains of counting relays at said oflice and at said station, respectively, means controlled by corresponding relays of said chains for transmitting alternate control and indication impulses over said line circuit to control and indicate said de vices sequentially, means controlled by each control impulse to operate corresponding relays of said chains to condition said line circuit for the transmission of the next succeeding indication impulse, and means controlled by each indication impulse to operate corresponding relays of said chains to condition said line circuit for the transmission of the next succeeding control impulse.

22. In a remote control system, an ofiice and a station, a series of devices at said station, control levers and indication means at said office for said devices, a normally open line circuit from said ofiice to said station, normally inactive control means for closing said line circuit to transmit a control impulse from each of said control levers to operate the corresponding device, starting means for setting said control means into operation to control the first device of said series, means responsive to each of said control impulses to open said line, means responsive to each opening of said line circuit following a control impulse to again close said line circuit to transmit an indication impulse from one of said station devices to operate the corresponding indication means at said oflice, means responsive to each of said indication impulses to open said line circuit, and means responsive to each opening of said line following an indication impulse to again close said line' circuit to transmit a control impulse to the next device of said series whereby each of said devices are alternately controlled and indicated in sequence over a single line circuit.

23. A remote control system of the synchronous step-by-step type comprising means for transmitting a series of stepping impulses over a line circuit from an ofiice to a station, the source of energy for the alternate impulses of said series being at said ofiice and the source of energy for the intervening impulses of said series being at said station, a series of station devices, one for each alternate stepping impulse, means for controlling each station device according to the character of the corresponding impulse, a plurality of indication devices at said office, one for each intervening stepping impulse and means for controlling each indication device according to the character of the corre sponding intervening impulse.

24. In a signaling system, an ofiice and a remote station connected by a line circuit, a series of devices part at said office and part at said station, impulse transmitting means operating over said line circuit to actuate said devices in sequence each to a position selectively determined by a particular impulse, and means controlled immediately by each of said impulses for selecting the device to be operated by the next succeeding impulse.

25. In a signaling system, two stations connected by a line circuit, a series of devices at each of said stations each adapted to be actuated by a line impulse transmitted over said line circuit from the other station, means for transmitting a series of impulses over said line circuit alternately from said two stations, each to actuate a particular device, chains of relays one at each of said stations, means for actuating equivalent relays of said chains in response to each of said impulses, and means controlled by said equivalent relays when actuated for conditioning a particular device of said series for operation by the next succeeding impulse over said line circuit.

26. In combination, an oiiice and a station, a chain of counting relays and a series of devices at said ofiice, a chain of counting relays and a series of devices at said station, a line circuit connecting said oflice and station, means controlled by said chains of counting relays for repeatedly closing said line circuit to transmit impulses over said line circuit, receiving means responsive to said impulses received over said line circuit to selectively actuate said devices sequen itally and alternately at said office and. at said station, sending means responsive to each impulse transmitted over said line circuit to terminate such impulse, and means responsive to the alternate operation of said receiving and sending means for actuating the counting relays 01 said chains sequentially.

27. A remote control system comprising an of fice and a plurality of stations, a synchronous selector located at the oflice, and a synchronous selector with portions thereof at each of said stations, means for operating said oiiice sy chronous selector in synchronism successively with each of said station synchronous selectors comprising a supplemental selector at each of said stations, that at the first station being controlled by the synchronous selectors at the office and at said first station, and that at each remaining station being controlled by the synchronous selectors at such station and at the next preceding station.

28. In a remote control system comprising an ofiice and a series of stations connected by a line wire, a selector at the ofiice, a selector at each station, means for synchronously operating the selectors at the office and at each station comprising apparatus for transmitting a group of impulses alternately from the office to one of the stations and from said one station to said ofiice over said line wire to operate the selectors at said ofiicc and said one station in synchronism, means controlled by the selector at said one station and efiective at the completion of said group of impulses to disconnect the line wire from the selector at said one station and to complete the line wire from the Ofi'lCE selector to the selector at the next station of the series to initiate the transmission of a group of impulses to said next station.

29. In a remote control system comprising an ofiice and a series of stations connected by a line circuit, a selector at theofiice, a selector at each station, means for synchronously operating the selectors at the oilice and at each station comprising apparatus for transmitting a group of impulses from the ofiice to one of said stations over said line circuit to actuate the selector at said one station synchronism with the office selector, means at each station for switching said line circuit to the ofiice from said station to the next station at the completion of said group of impulses and for initiating the transmission of a group of impulses from the ofiice to said next station to actuate the selector at said next stationin synchronism with the office selector, and means at each of said stations to initiate the operation of said oflice selector to etlect the op eration of all of said station selectors in sequence 30. In a centralized traffic controlling system for railroads, in combination, an office and a plurality of stations, a series of devices at said stations including at .least one device at each station, means including selector apparatus at said office and at each of said stations to successively indicate at said ofiice the condition of each of said station devices, means at each of said stations for setting said selector apparatus into operation to indicate the condition of a device at such station, and means responsive to the operation of said selector apparatus when indicating the condition of any station device for setting said selector apparatus into operation to indicate the condition of the next succeeding station device.

31. In a remote control system including an ofiice and a plurality of stations, a selector comprising a chain of counting relays at said office, a second selector comprising a chain of counting relays of which certain ones are at each of said stations, said selectors being normally deenergized and adapted when operated to close a series of contacts in sequence. and to close corresponding contacts of diiierent selectors simultaneously, means for transmitting impulses from said oihce to each of said stations in turn to operate said contacts in sequence, means controllable from said office or from any of said stations for initiating operation of said means; means at each station for controlling devices at such station by the contacts of the associated selector contacts and by said impulses.

32. A selector of the relay chain type, comprising a series of counting relays, a pair of normally deenergized line relays, a normally deenergized slow release relay adapted to be picked up when one of said line relays is first energized and to be maintained in the energized position when the other of said line relays is energized repeatedly; pick-up circuits for each of said counting relays, the circuits for consecutive relays being connected to the contacts of said line relays alternately, each of said circuits except the first including 9. normally open front contact of the next preceding counting relay, the first circuit including a back contact and the remaining circuits each includ ing a front contact of said slow release relay; a holding circuit for each counting relay including a back contact of the next succeeding counting relay, and means for energizing said two line relays alternately to energize said counting relays one at a time in sequence.

33. In a remote control system, means for transmitting a series of impulses over a line wire to a remote station comprising a pair of line relays, starting means for energizing the first of said relays by a momentary impulse; means effective when said first relay becomes energized for preparing a circuit for the second relay, said circuit including a source of energy, a back contact of said first relay, and said line wire and becoming closed when the first relay is released to energse said second relay and to initiate the transmission of an impulse over said line wire; means effective when saidsecond relay becomes :rgized to open said line wire to terminate said impulse and to then close a circuit through said line wire and said relay; means at the remote station responsive to the termination of said first impulse for transmitting a second impulse to said line wire to again energize said first relay for repeating the above described cycle of operations.

34:. A remote control system comprising a series of stations and an oflice, line circuits for connecting each of said stations in turn with said office, a device at each of said stations, a selector relay and an indication stick relay for each device at said office, a pick-up circuit for each indication relay including a front contact and a holding circuit including a back contact oi the corresponding selector relay, means forenergizing said selector relays in sequence, line controlled means effective when each selector relay is energized for closing the pick-up circuit of the corresponding indication relay, and means for controlling said line controlled means selectively according to the condition of the corresponding device at the remote station.

35. Means for continuously indicating whether or not each of a series of contacts is closed, each said contact being located at the remote end of an intermittently rendered available line circuit, comprising a stick relay for each contact, each having a pickup circuit a holding circuit, means effective when any of said contacts opened or closed for briefly opening the holding circuit of the corresponding stick relay, and other means operating over said line circuit and eiiec tive during the time that said stick relay is'open to control the pickup circuit for said stick elay selectively in accordance with the position or the associated contact of said series.

36. A centralized traffic controlling system railroads comprising an office and a p urality traffic governing devices located along the trackway, a plurality of relays at the office one for each said device, a pickup circuit and holding circuit for each said relay, apparatus for rupturing all said holding circuits one at a time mined sequence, another relay th for successively placing other relay under the control of said devices, means for con-- trolling the pickup circuit of relay by said other relay when the stick circuit for such relay is open.

37. A centralized traffic controlling system for railroads comprising an office and a plurality of traffic governing devices located along the trackway, a plurality of relays at the office one for each said device, a pickup circuit and a holding circuit for each said relay, apparatus for rupturing all said holding circuits one at a time in a predetermined sequence, a polar relay at the office, means controlled successively by said devices for energiz ing said polar relay in one direction or the other in accordance with the position of the device, the

pickup circuit for each stick relay including a polar contact of said polar relay and being available only when the stick circuit for such stick relay is ruptured.

38. In a remote control system, an oifice and a plurality of stations connected by a normally open line circuit including a pair of iine wires and a line relay at the office, starting means at each station for closing the portion of said line circuit extending from said station to the office to energize said line relay, sectionalizing means at each station efiective when operated to open the por tion of the line circuit leading from the oflice through said station to the next succeeding station, and to complete a message circuit including said line wires for communication between the ofiice and said station, means responsive to the energization of said line relay by said starting means to operate the sectionalizing means at the first station, and means responsive to the energization of each message circuit for restoring the sectionalizing means at the corresponding station and for operating the sectionalizing means at the next succeeding station, whereby communication between the oflice and each station in turn is established in response to the operation of the starting means at any station.

39. In a remote control system, an ofiice and a plurality of stations connected by line wires, a series of movable devices at least one located at each station, means set into operation by a change in position of any one of said devices for transmitting an impulse from the ofiice to the station nearest the ofiice, means at each station rendered eiTective when an impulse transmitted to such station is terminated for transmitting a return impulse from such station to the oifice, and for then initiating the transmission of an impulse from the oii'ice to the next station more remote from the office, means at each station controlled in accordance with the position of the movable device at such station for determining the character of the impulse transmitted from such station, indication means at the ofiice for said movable devices, and means for controlling said indication means in accordance with the character of said impulses.

40. A remote control system comprising an ofiice and a plurality of stations connected by a line wire, a transmitter contact at each sta-- tion, means at each station for closing the contact at said station to transmit current over the line wire to the office when said line wire is availabe, means at each station responsive to the flow of current in said line wire to open said contact and to then close the line wire from the ofiice through said station to render the line wire available at the next station more remote from the office, means at each station for controlling the character of current transmitted from such station, and indication means at the office for each station selectively responsive to the character of current transmitted from such station.

41. A remote indication system for railroads compris ng a plurality of devices distributed at d fierent stations along a railway, a purality of intermittently available line circuits each including the same line wire for connecting each of said station devices with an associated device at the ofiice, impulse transmitting means adapted to operate over said line circuits, means controlled over sa d line wire and responsive to a change in condition of any of said devices to set said impulse transmitting means into operation to transout a series of impulses for seecting each station device in turn and including means responsive to each impulse of said series for transmitting a re turn impulse to select each oiiice device in turn, means for controlling the station devices each in accordance with the character of a selected impulse of said series, and means for controlling the office devices each in accordance with the character of a selected return impulse.

42. In combination with a line circuit, a Wind ing and front contact of a line relay in said line circuit, stepping means adapted to be operated in response to repeated deenergization and reenergization of said line relay, and means controlled by said stepping means eiiective when said line relay has been deenergized to close a shunt around said front contact until said line relay again becomes energized.

43. In combination, a pair of line circuits each including the same line wire and arranged to be closed alternately, the first including the winding and a front contact of a first line relay, and the second including the winding of a second line relay and a back contact of said first line relay, stepping means operated progressively in response to the alternate energization and release of said two line relays, and means controlled by said stepping means effective when either line relay has been energized and released for preparing the line circuit for the other line relay, whereby said other line relay may be energized and released.

44. In combination, a pair of line circuits each including the same line wire and arranged to be closed alternately, the first including the winding and a front contact of a first line relay, and the second including the winding of a second line relay and a back contact of said first line relay, stepping means operated progressively in response to the alternate energization and release of said two line relays, means controlled by said stepping means for closing a shunt around the front contact in the first line circuit when the second line relay is released, and means for opening said shunt when the first line relay becomes energized.

45. A synchronous selector remote control system comprising a stepping line wire, a pair of line relays arranged to be energized alternately and repeatedly, a chain of counting relays arranged to be energized one at a time in sequence as said line relays are energized alternately, a series of control circuits, one for each alternate counting relay, each including a front contact of said counting relay, the winding of one line relay and said line wire, a series of indication circuits, one for each intervening counting relay, each including a front contact of said intervening counting relay, the winding of the other line relay and said line wire, means for transmitting distinctive impulses over said control and indication circuits, means responsive to said impulses to operate said line relays, and means controlled by said line relays to operate said counting relays.

46. A synchronous selector remote control system comprising an office and a plurality of stations, a synchronous selector at the office, a synchronous selector having a portion at each of said stations, a plurality of steppin circuits completed successively and each including a stepping wire for eiiecting operation of each of said station selectors in synchronism with a corresponding portion of the ofiice selector, said selectors being normally at rest ,in a zero position, means for transmitting a plurality of messages successively over said stepping circuits during operation of said selectors, and means including said stepping Wire and effective at each station provided said selectors are at rest in their zero position for initiating the operation of said selectors.

47. A synchronous selector remote control system comprising a stepping line and a message line, a line relay in said stepping line, a chain of counting relays arranged to be energized one at a time in sequence as line relay actuated repeatedly, a series of control circuits, one for each alternate counting relay, each including sage no and a contact of th corresponding counting relay, a series of indication circuits, one for each intervening counting relay, each including said stepping line and a contact of the corre sponding counting relay, means for transmitting distinctive control impulses over each said contrcl circuits, and means for transmitting distinctive indications over each of said indication circuits.

48. A synchronous selector remote control system comprising an ofhce and a plurality of stations, two series of stepping contacts, one at the oflice and the other at the stations, each adapted to be closed one at a time in sequence for rendering available a series of control message circuits from the olfice to each station in turn during a single cycle of operation. of said contacts, a rality of stick relays at the stations, including one for each message circuit, and at least one at each station, a plurality of stick relays at the office ineluding one for each station, means rendered effective during said cycle of operation oi said contacts to complete selected message circuits to pick up selected ones of the stick relays at a station it and only if the oifice stick relay station is energized, means for selectively picking up said ofiice stick relays, means for initiating the operating cycle of said contacts, and means controlled by said contacts for releasing said oifice stick relays.

so. In a centralized traific controlling system for railroads, a control ofiice, a plurality of field stations, a stepping circuit and a message circuit extending from the control office to the several stations, means in the control. office manually controllable by the operator for applying to the stepping circuit one at time a plurality of different combinations of impulses, each combination of impulses being characteristic of a narticular station and the controls for that st in. and means at each station for governingfithc energization of the message circuit when impulsesare applied to the stepping circuit for particular station to conform with the indications to be transmitted from that station to the control ofilce. l

50. In a system of the type described, a control ofiice, a field station, a stepping circuit connecting the control office and the field station, means for energizing said stepping circuit with time spaced impulses of selected polarities, step-by step means at the field station responding to take one step for each of said impulses irrespective of its polarity, and means at, said field station distinctively controlled on each step in accordance with the polarity of the impulse for that step.

51. In a centralized controlling system for railroads, a control office, a plurality of field stations, a stepping wire extending from the control oillce through. the several stations, means in the control cffice for energizing said stepping wire with a series of time-spaced impulses of selected polarities, and a bank of stepping relays at the stations operated one at a time and one for each time the stepping circuit is energized by an impulse irrespective of the polarity of that impulse. I

52. In a centralized traflic controlling system for railroads, a plurality of stations, a circuit connecting said stations, means placing a plurality of series of positive and negative impulses on said circuit each series comprising a predetermined number of. impulses, and means determining whethe" a particular impulse shall be positive or ne ative, whereby the number of said distinctive series constituting said plurality of series is equal to two raised to the power of a number equal to the predetermined number of impulses in a series.

In a centralized traffic controlling system for railroads, the combination with a stepping line and a message line connecting an oil-ice and a plurality of'stations, a series of relays in said office operated successively in response to a series of impulses each of controllable character impressed upon said stepping line, means associated with said series of relays and responsive to each impulse to determine the character of the next succeeding impulse, means at the stations selectively controlled in accordance with the character of said impulses and means at the office controlled by said stepping relays for indieating traffi-c conditions at saidstations over said message line;

54.. In a centralized trafiic controlling system for railroads, a control ofiice, a field station, a line circuit connecting said control oifice with field station, a plurality of traffic controlling devices at said field station, a plurality of control levers at said control oifice corresponding to said traffic controllin d vices, means for impressing a series of impulses: on said line circuit having positive and/or negative polarities in accordance with the positions of said levers, relay means at said field station repeating each impulse of said series irrespective of its: polarity, a series of stepping relays at said field station operated step-bystep icy said relay means, contact means at said field station repeating the polarity of each impulse of said series, and an electro-responsive device at a field station for each step controlled by said contacts on that step in accordance with the polarity of the impulse repeated thereby.

5 5. In a centralized trafiic control system for railroads, a control omce, a field station, a line circuit connect ng said control oilice with said field station, means: for impressing a series. of time spaced impulses on said line circuit, step-loystep means at said control office and at said field station, relay means at said ofiice and at said field station repeating the impulses of said series irrespective of the polarity of such impulses, means controlled by relay means for causing their respective step-b-y-step means to operate one step for each impulse, manually governable means: at said control office for selectively determining the polarity of each impulse of said series, contact means at the station repeating the polarity of each impulse of said series, and an electro-responsive device at the field station for each step controlled by the contact means on that step in. accordance with the polarity of the impulse repeated thereby.

56. In combination, a line wire connecting a local office and a distant way station of a railway system, a source of energy at each end of said line circuit, a control relay at said way station, indicating relay at said cflice, a way station series relay included in series with the Way station source when said indicating relay is energized, an

office series relay included in series with said ofiice source when said control relay is energized, and means for excluding said respective series relays from said respective sources.

57. In combination, a line wire connecting a local office and a distant way station of a railway system, a trafiic controlling device at said way station, a source of energy at each end of said line circuit, a control relay at said way station for controlling said traffic controlling device, an indicating relay at said office, a way station series relay i cluded in series with the way station source when said indicating relay is energized, an oflice series relay included in series with said ofiice source wh n said control relay is energized, and means for excluding said espective series relays from said respective sources by momentary opening of said respective energizing circuits.

58. In a remote control system, two stations connected by three conductors, at least two operating units units at one of said stations, and means for transmitting over the conductors in a single impulse a control signal indicating the desired one of three possible operations for one operating unit and the desired one of two possible operations for a second unit.

59. In a remote control system, two stations connected by three conductors, groups of operating units, and means for transmitting over the conductors in a single impulse a report signal indicating one of three conditions in one ating unit or group and one of two conditions in a second unit.

60. In a train dispatching system, a control station and substations connected by three line wires, signalling units at the control station, one for communication with each substation, and concatenated distributing switches at the control station for associating the signalling units successively with the line wires and for establishing successive impulse periods for each unit.

61. In a train dispatching system comprising a control station and substations connected by three line wires, receivers at the control station, one for each substation for reception of supervisory signals, and concatenated distributing switches for associating the receivers successively with the line wires and for establishing successive impulse periods during the association of each receiver, successive control and report impulse periods being established during each such association.

62. In a train dispatching system comprising a control station and substations connected by three line wires, a receiver at the control station responsive to current combinations in the line wires adapted to respond selectively during a single line impulse to one of three positions of one selector at a substation and to one of two positions of a second selector at a substation.

63. In a train dispatching system, a control station connected by three line wires to a substation, a plurality of units at the substation, and a sender at the substation adapted to transmit during a single line impulse a supervisory signal indicating one of two conditions of one unit and one of three conditions of another unit.

64. In a train dispatching system comprising a control station and a substation connected by three line wires, a receiver at the control station and a receiver at the substation, means at the control station for controlling the receiver at the substation, and a sender located at and responsive to the receiver at the substation for transmitting signal impulses isochronously with said receiver at the control station.

65. In a train dispatching system, stations connected by three line wires, a source of current, means at each station for variably applying current from said source to said line wires, a receiver at one station comprising a polar and a neutral relay, the polar relay actuated by current in one line wire to close one or another circuit when the line current is positive or negative and neither relay actuated when the current is zero, the neutral relay, actuated by local energy through the contacts of the polar relay, being released to close a third circuit when the line current is zero, and traiii-c controlling devices at said stations variably operated upon the closing and opening of said circuits.

66. In a centralized traffic control system for railroads, the combination of a stepping line Wire, a message line wire and a common return wire connecting an ofiice and a plurality of stations, means in the oflice for impressing upon the stepping line wire and the common return wire a series of impulses each of controllable polarity, receiving means at each of the stations controlled in accordance with the polarity of the impulses of said series, control levers and indication means at said office, trafiic controlling means at a particular station, and means controlled by said receiving means and acting through the medium of said message line wire and common return Wire for at times controlling said indication means in accordance with conditions at such station and for at other times controlling said trafiic controlling means in accordance with the positions of said levers.

67. A selector system for transmittin controls from an ofilce to a plurality of stations and for receiving indications at said office from any one of said stations comprising, a stepping line connecting the ofiice and said stations, means for impressing a series of impulses each of controllable character upon said stepping line, stepping relays at the office and at said stations operable sequentially by said impulses, a message line connecting the office and said stations, means at the stations selectively controllable in accordance with the character of said impulses, a plurality of indication devices at said office, means controlled by said stepping relays for controlling a selected one of said indication devices to one position or another depending upon whether said message wire is energized or not on a particular step during the operation of said relays, and means controlled by traffic conditions at a selected station for controlling the energization of said message wire on said particular step.

68. In a centralized trafi'ic controlling system for railroads, a stepping line and a message line connecting an oilice and a plurality of stations, means in the ofiice for impressing a series of positive and/or negative impulses sequentially upon said stepping line, means at a particular station selectively responsive to the polarity of selected impulses of said series, indication means at the oflice for each station, and means controlled by said selected impulses for controlling the indication means for said particular station over said message wire in accordance with conditions at such station.

69. In a communication system of the multiple impulse type for centralized traffic control, a stepping line circuit including a line relay, a chain of neutral stepping relays arranged in two groups which relays are operated sequentially by the operation of said line relay, means energized in response to the operation of said stepping relays for opening and closing said line circuit, a selector relay, means for causing operation of saidsecond group of stepping relays following operation of the first group if said selector relay is in a predetermined condition, and means for controlling said selector relay from a distant point.

'70. In a normally at rest remote control system of the code selective type, a control oflice, a plurality of field stations, a normally deenergized first line and a plurality of other lines connecting said control office with said field stations, means for energizing said first line at said oflice to start the system into a cycle of operation, means at said control office effective during said cycle for applying distinctive impulses to said first line in series with said other lines in different combinations, and means at each of said stations selectively responsive to said distinctive impulses and said different combinations of said first line 19 during the cycle.

NORMAN F.- AGNEW.

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