US2398588A - Remote-control system - Google Patents

Description

April 16, 1946. 'A. B. MILLER REMOTE CONTROL SYSTEM Filed Nov. 25, 1943 '7' Sheets-Sheet l INVENTOR BjVl'ZleP.

1145' ATTORNEY April 16, 1946. A. B. MILLER 2,398,588

REMOTE CONTROL SYSTEM F iled Nov. 25, 1945 7 Sheets-Sheet 2 I 1 IINVENTOR Al/ MBJVJ'ZZQP.

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April 16, 1946. A. B. MILLER I 2,398,588

REMOTE,CONTROL SYSTEM Filed NOV. 25, 1945 Sheets-Sheet 7- Patented Apr. 16, 1946 nniuo'rn-con'raot SYSTEM Alfred B'. Miller, Edgewood, Pa., assignor to The I Union Switch & Signal Company, Swlssvale, Pa., a corporation oi Pennsylvania Application November 25, 1943, SerialNo. 511,681

14 Claims.

My invention relates to remote control systems for the control from a central oflice of selected devices located at distant stations, and for also indicating at the ofiice the condition of such devices and of other devices located at such sta-' tions, by means of impulse codes transmitted intermittently over line wires.

In its specific embodiment my invention and has for its principal object the provision of a system for the remote control-of interlocked track'switches and signals from a central ofiice .or control tower and for indicating their condition and for reporting train movements at the tower by means of which routes may be set up with substantially no more delay thanwhen direct .wire control is used. The system of my invention is adapted particularly for use in the vicinity of large-railway terminals where the controlled functions are scattered over sucha wide area and their number is so large as to make direct wire control as employed heretofore uneconomical. In the practice of my invention, the terminal area is divided into zones. of suitable sizeand a separate set of equipment such as is disclosed herein is provided for the control and indication of the interlocked switches and signals in each zone. A

three wire line circuit extending from a code zoneprovides a channel for the transmission ofcontrol codes to the station. A second three wire I relates to centralized trafiic control systems for railroads,

line circuit extends from a code transmitter at I the station to an individual receiver at the omce and provides an independent channel for the I transmission of indication codes'to the omce.

Normally all three wires of the three wire line code, the successive impulses of which are adapted to operate polar stick relays for governing the various railway .tramc governing devices in the i zone or for indicating their condition at the omce.

The coding apparatus is adapted to control two in order, each in accordance with a diflerent one of the remaining impulses of the code. J

In setting up a traflic route it is the practice to operate the levers controlling the track switches first, and to defer the'operation of the signal lever for clearing the signal for the desired route until the establishment of that route is verified by the display of the proper switch indications. Accordingly the switch controls are placed in one group and the signal controls in the other. In the case of indication codes, the various indications are divided arbitrarily into two groups and a change in condition of any indicating device initiates a code for successively indicating all of the devices of its group. If the changes occur so frequently as to operate the transmitter con 5 tinuously, the two groups of indications are transmitted alternately thereby limiting the delay in receiving .an indication of a change in either group to th time required to transmit one code.

A further feature of my invention resides in the provision of coding circuits using relays having unusually fast operating characteristics, the normal speed of the system being at the rate of 35 impulses per second. The time consumed in transmitting a code being hardly more than that required to move a control lever therefore-introduces no delay inth operation of the plant even when controlling trains running under close headway.

A feature of m invention is the provision of improved arrangements for interlocking the code control circuits at the oiilce to enforce the carry-- cleared .again by a repetition of the code by which 7 it was originally cleared unless a code for restoring it to stop is interposed.

The system herein disclosed is an improvement upon that shown in my prior application for Letgroups of such relays, the relative polarity of they flrstimpulseofeachcodeselectingtherelaysof o e g oup ortheother for operatiomoneatatlme In the accompanying drawings, Figs. 1, 2, 3A

ters Patent of the United States, Serial No. 403,- i 494, filed July 22, 1941, for Remote control sys-- and 3B, and Figs. 4A, 4B and 4C illustrate difierent component parts of the system of my invention, and Fig.5 shows how these views may be assembled to form a centralized trailic control sys-' tem illustrating one form of apparatus emb dying my invention. More particularly, Fig. 1 shows the transmitter by means of which the impulse codes are generated and delivered to the three wire line circuit formed by the line wires'X, Y and Z by means of which each transmitter is connected to the associated receiver. Fig. 2 shows the receiver which responds to the codes received over the line wires X, Y and Z. As shown in the lower portion of Fig. 5, a transmitter such as is shown in Fig. 1

' is located at the oflice and connected b the three line wires to a receiver of Fig. 2 located at the station to effect the transmission of control codes from the oflice to the station. The transmission of indication codes is effected independently by similar apparatus over a second three wire line circuit, and therefore may be illustrated by the same views, by-locating Fig. 1 at the station and Fig. 2 at the oflice, as illustrated in the upper portion of Fig. 5.

Figs. 3A and 3B, taken together as in Fig. 5, show a portion of the operator's control panel arranged for the control of a particular zone or section of the interlocking plant corresponding to the miniature track diagram at the top of Fig. '3A. Fig. 3A also shows a group f polar stick'indication relays K controlled by the oilice receiver of Fig. 2, and a circuit network including a group of route relays RH and LH for governing the transmission of control codes for clearing the si nals. Fig. 3B shows the switch levers SW, signal levers SIG and call on push buttons PB together with certain lever repeating relays P, for governing the transmission of control codes by the ofl'ice transmitter of Fig. 1.

Figs, 4A, 4B and 4C taken together show the trackway circuits and apparatus at the station. a

More particularly, Fig. 4A shows in the upper portion the track plan for the controlled zone together with the circuits for the track relays TR and their repeating relays TP, the switch indication relays WP and their repeating relays NWP track switches W. Fig. 4C also shows circuits for the signal slotting relays TPS.

Similar reference characters refer to similar parts in each of the several views.

.As will be clear from the drawings, each track switch is identified by an odd number, switch IW, 3W or SAW, for example, and each signal by aneven number, as illustrated by the signals iRA,

- ZLB, etc., the corresponding number being prefixed to the designation'of each relay associated with such switch or signal, for ready identification and in order to enable the operation of the system to be more readily traced. Local batteries .are provided at the ofiice and the station for ento be understood to be railway signaling relays of the types commonly employed in relay interlocking systems, with the exception of the stick polar control relays WS, LHS, etc. These stick polar relays and also the indication relays K of Fig. 3A, the lever repeatin relays P of Fig. 3B, relay CRI of Fig. 1, and relays ICD, 2CD, CRP and CR2 of Fig. 2 are preferably of thetype shown in Letters Patent of the United States No. 2,256,653, granted September 23, 1941, to Clarence S. Snavely. Each such relay has four normal and reverse contacts a, b, c and d, and is adapted to hold its contacts in their last operated position when deenergized. operating its contacts to the normal 'or left-hand position when positive current is supplied to the left-hand terminal of its winding, and to reverse when supplied with current flowing in the opposite direction. The relays Yl, Z1 and Z? of Fig. 1, and relays Y2 and Z2 of Fig. 2 are of the same type but have only two normal contacts a and c and two reverse contacts 1) and d. The remaining polar relays shown in v Figs. 1, 2, 3A and 3B are biased as indicated conand BWP, the switch locking relays LR and a section locking relay IWSR, and in the lower portion the circuits for controlling the transmission of indication codes by the station transmitter of Fig. 1, located at the left of Fig. 4A as shown in Fig. 5. Fig. 4B shows in the upper portion a signal circuit network of circuits for the signal mechanisms G. It is to be understood that the signals are of the well-known search-light type, located as shown in the track plan and each having an operating mechanism G such as that shown in the Blake Reissue Patent No. 14,940, reissued August 31, 1920. Fig. 4B shows in the lower portion, circuits for signal indication relays RGP and LGP repeating the stop indications of the signals, and circuits controlled thereby for governing the approach locking stick relays RAS and LAS, and the time element relays TE and stick relays TES associated therewith.

Fig. 40 shows the circuitsfor the stick polar control relays governed by the station receiver of Fig, 2, these including the switch control relays WS, the signal control relays LHS and RES, the call-on signal control relays COS, and a relay MCS for controlling a maintainers call signal device comprising a horn H and a lamp MCE.v The relays WS controlswitch operating relays ventionally by biasing springs on their contacts. The biased polar relays each have two contacts a and c which close when positive current is supplied to the left-hand terminal of its winding, and two contacts 17 andd which close when the relay is deenergized or is supplied with current flowing in the reverse direction.

The neutral relays shown in Figs. 1, 2, 3A and 3B are quick acting relays, preferably of the type shown in Letters Patent of .the United States No. 2,259,183, granted October 14, 1941, to Clarence S. Snavely. Each of these neatral relay is equipped with six front contacts a to f, inclusive,

and three back contacts 9, h and i.

The relay circuits as shown include various electronic rectifiers and resistors for governing the time of operation of the relays and to eliminate sparking atthe contacts, the resistors bearing numerical designations such as 20, 100, etc., corresponding to the values in ohms, commonly used in practice, in order to enable their effect upon the relay operations to be more readily understood.

Theswitch and signal levers SW and SIG of Fig. 3B, and also the lever MC, which lever controls a maintainers callsignal relay MCS shown in Fig. 4C, are to be understood to be of a type combining the functions of a spring return starting push button and a rotatable control lever in a single device, such as is shown in Letters Patent of the United States" No. 2,289,736, issued July 14, 1942, to Clarence S. Snavely and Regis H. Zetwo. Each such lever is normally locked in its last operated position by a spring actuated detent and i through relay L and over contact d of relay Tl the lever must first be pushed to open its contact a, also closing alcontact b, if required, to disenage the detent, and may then be rotated to move its control contacts 0 and d to the desired position. The release of the lever handle allows the spring to lock the control-contacts closed, and also closes its contact a, the latter completing a circuit for initiating the transmission of the code.- Each switch lever SW has associated therewith a correspondence relay WC, a switch indication relay WK, a lock indication relay LK, a lever repeating relay P, and an indication lamp WE, all arranged as shown in the Remote control system of Letters Patent of the United States No. 2,292;

, 245, issued August 4, 1942, to Clarence S. Snaveiy et' al. Each three position signal lever SIG has associated therewith a normal indication relay NK, 2. signal indication relay GK, an indication stick relay GKS, two lever repeatin relays LP and RP and two route relays LH and RH. Each call-on push button PB has a repeating stick relay CO associated therewith.

or 2STEB, provided for test purposes, to terminal C over wire I: or ll. At the-office, Fig. 33, wire I 3 is connected to terminal C over contacts a of the switch levers SW and c! the lever MC, and wire II is connected to terminal C over contacts a of the signal lever SIG and the associated callon push buttons PB, while at the station, Fig. 4A,

wires l3 and H extend to terminal 0 over contacts' of the indicating relays, which may be arranged in two groups in any desired manner.

Each relay IST or 2ST controls aistorage remined, comprising circuits for relays TI and T2 spectively, to Fig.- 3B or Fig. 4A. Relay STP initiates the'code transmission by energizing the The three wire control and indication line circults over which the codes are transmitted between the ofllceand station each includes at the transmitting end, Fig. 1, a line battery 80, the winding of a line check relay L0 and contacts of three transmitter relays Tl T2 and T3 by means or which the positive terminal of battery 80 may be connected to line wires X, Y and Zjrespec-g tively, and at the'recelving end, Fig. 2. the line circuits include the windings of three line relays Ll, L2 and L3 which repeat the operation of the corresponding relays T.

Relay T3 is energized when the system is in its normal at rest condition over a stick circuit extending from terminal B over back contacts h of relays T2 and TI, back contact 9 of atransmltter ch'eck relay TP and the front contact a and winding of relay T3 to terminal C. Consequently the line circuit is normally closed from the positive terminal of battery 80 through the upperwinding of relay L0, contact b of relay T3 to line wire Z, and thence through relay L3, thereby energizing relays LI! and L3 in series, the circuit then extending difierentially through the windings o1 relays Li and L2 to line wires X and transmittercheck relay TP to release relay T3 by opening its stick circuit already traced, and to also release a reset check relay WI which is normallyenergized over a circuit extending from terminal 13 at the front contact 0 of relay L0 over front contact I of relay T3, through relays WI and Zl in series, to terminal C.

The release of relay WI completes the first of the circuits prepared for relays TI and T2 by relay ISD or 25D. Relay Tl or T2 picks up and 1 impulses of the code. Achain repeat relay CRl Y and over contacts c and d of relay ,T3 to the negative terminal of battery 80, so that relays LI and L2 normally stand released.

In Fig. 1, relay T3 is released for the duration of each code, and either relay TI or T2 is Picked up on-each step. Whenrelay Tl picks up, the positive terminal 01 battery 80 is connected to llne'wire X, thence from left to right through relay LI, and in the reverse direction through provides connections for energizing relay OI as the next in order. after relay OS, to operate the relay chain through asecond cycle, on the last .step of which relay Ol 2 operates in place oi relay O6, to terminate the code.

As shown, the transmitter is arranged to de liver a code of twelve impulses. This number in practice is varied by providing different numbers of counting relays. at'diflferent locations in accordance with the number of devices to be controlled or indicated in the different zones.

The transmitter of Fig. 1 also includes two V .oode operation of the corresponding relays Tl,

relay L2 to line wire Y and contact 0 of relay TI to the negative terminal C of battery 80, thereby energizing relays L0 and LI in series, relays L2 and L2 'remainingreleased; When relay T2 picks up, its contacts d and 0 connect the'positive terminal of battery to the line wire Y, and the negative terminal to line, wire X, thereby .ener-' gizing relays L! "and L2 in'series, relays LI and Ltremaining released. The codes thus comprise a series of impulses, each comprising an X or Y impulse with a single Z impulse between each two successive codes. v c

To initiate the two different series or code impulses. two code storage relays l ST and-2ST are provided. Each storage relay ST- is normally energized over a stick circuit extending from ter-. minal B over its own front contact a and lower winding, and a contact are push button ISTB T2 and T3, that is, relay L3 releases for the duration of the code and relays LI and L2 respond to the X and Y impulses to control the relays W2, X2, Y2, Z2, CR2 and the counting relays l to 6, inclusive, and i2, each of which operates substantially in unison with the corresponding relay of Fig. l. The receiver also includes two delivery relays lCD and 2CD which respond to the X or -Y character, respectively, of the first impulse and prepare circuits including wires 62--|.2 or 82-42, over which-the corresponding group of polar stick relays of Fig. 3A or Fig. 4C are controlled. Relay W2 is normally held energized and relays ICD,

the first counting relay I, and. is released in response to the operation of the line relay LI or L2 by the first impulse of a code.

The operators control panel of Figs. 3A and B includes two code indicator lamps .CE and KE. Lamp CE is energized over wire I3 and back contact a of relay T3, and is lighted for the duration of each control code. Lamp KE is energized over wire 39 and back contact d of relay L3, for the duration of each indication code.

Having thus pointed out the general features of the system of my invention, I shall now describe its operation under difierent assumed conditions by tracing the circuits in detail, starting with the apparatus in its normal at rest conditionas shown, with all track switches normal and all signals at stop.

I shall first assume that the operator reverses the switch lever ISW, Fig. 33, to set up a route to enable signal 2RC to be cleared. When lever ISW is pressed to release the lever latch, the opening of its contact a disconnects terminal C from wire I3, releasing relay IST, and the closing of its contact I) connects terminal B over contact a of relay ILK to wire 31 to complete a circuit through relay IWK to terminal C to operate relay IWK to its reverse position. Relay IWC, normally energized over the left-hand or normal contact of lever ISW, the left-hand contact a of relay IP and the left-hand contact b of relay IWK, is thereby released, and lamp IWE becomes lighted over the circuit from terminal B at the left-hand contact d ofrelay ILK, the right-hand contact (I of relay IWK, lamp IWE to terminal C; The opening of contacts a of relay IWC in the route circuit network of Fig. 3A prevents the transmission of code elements for clearing the signal for any route over switch IW. The closing of the reverse contact 0 of lever I SW completes a circuit from terminal B through the upper winding of relay IP and contact a of relay IWK to terminal 0', causing relay IP to reverse. The release of lever ISW in the reverse position-reconnects terminal C to wire I3, completing a circuit from terminal B at contact e of relay T3 over contact b of relay STP through the upper winding of relay ISP and over contact b of relay IST to wire I3 and thence toterminal C, so that relay ISP picks up. The closing of contact a of relay ISP completes a circuit from terminal 3 at contact e of relay T3 over contact h of relay TP through the upper winding of relay STP, contact a and the lower winding of relay ISP and thence over contact b of relay IST and wire I3. to terminal C, over which relay STP picks up and relay ISP :is held energized, the circuit over which relay ISP picked-up being opened at contact b of relay STP, while contact d of relay STP opens the pick-up circuit for relay 2S5.

The closing ofcontact c of relay STP completes a circuit from terminal B at contact b of relay WI over contact c of relay STP, contact a of relay ZI, through the upper winding of relay ZP-and the winding of relay TP to terminal C over which relay TP is picked up, and relay 2? is held normal. The closing of contact I) of relay '1? completes a stick circuit for relay LI) extending from terminal B over contacts 12. of relays T2 and TI, contact b of relay TP, contact (1 and the lower winding of impulses when its upper winding] is deenergized, so that relay LII remains picked up for the dura! tlon' of the code. The opening of contact 9 or relay 'I'P opens the stick circuit for relay T3 already traced, so that relay T3 releases to open the line circuit.

The opening of contact e of relay T3 disconnect terminal B from the pick-up circuits for the SP relays, but relays STP and ISP are held energized over the stick circuit for relay ISP extending to terminal 13 at contact d of relay TP. Contact f of relay T3 opens the circuit for relay WI, which is slow to release and remains picked up until relays XI, ISD and OI become energized over circuits closed try the release of relay T3,

which will now be traced.

Relay XI picks up over the circuit from terminal B at contact 0 of relay L0, contact 71. of relay T3, contact a of relay WI, relay XI, contacts :i of relays TI and T2, contact 0 of relay ZP, through the upper winding of relay YI to terminal C, checking relay YI normal, and relay XI completes a stick circuit over its own contact a. Relay ISD picks up over the circuit from terminal B'at contact g of relay T3, contacts c of relays ISP and WI through relay ISD to terminal C, and relay ISD completes a stick circuit over its own contact a. The closing of contact 9' of relay T3 completes a circuit over wire I9 to light lamp CE, and over contact 0 of relay ZI contact e of relay WI and contact c of relay CRI through relay OI to terminal C. Relay OI picks up and completes a stick circuit at its contact a.

Relay WI now releases, relays XI, ISD and OI remaining energized over their respective stick circuits. Contact I) of relay WI opens the pickup circuit for relay TP, but relay '1? is slow to release and remains picked up.

The release of relay WI completes a stick circuit for relay STP from terminal B at contact g of relay T3, over contact h of relay WI, contact a and the lower winding of relay STP to terminal C. Relay STP is thus held energized to complete the code in the event terminal C is disconnected from wire I3 by lever operation and relay ISP is released during the code transmission. The release of relay WI also completes a circuit for selecting the character of the first impulse, of the code which extends from terminal B at contact b of the hand stepping switch HSI over contact-c of relay TP, contact 9 of relay WI, contacts a of relays ZP, YI and CRI, contacts 0 of relays ISD and OI, wires 2I and I5, contact 9 of relay T2 through the winding of relay TI to terminal C.

Relay TI picks up and supplies an Ximpulse to the line circuit, and completes a stick circuit from wire I5 over its own contact a, contact 0 of switch HSI to contact a of relay YI, over a path already traced to terminal B at contact b of switch HSI. Contacts and of relay TI pick 7 up and shift the circuit through relay X! from the lower winding of relay ZI, thereby reversing relay ZI. The closing of contact e of relay TI completes a stick circuit for relay TP extending from terminal B at its contact a over contact c of relay XI, contact e of relay TI, contact a. or b of relay ZI through relays ZP and TP to terminal C, whereby relay T? is held" energized and relay ZP reverses in response to the reversal of relay ZI. The reversal of relay ZI also picks up relay 02 over the circuit extending from terminal B at contact a of relay T3, contact d of relay ZI,

contact b of relay OI through relay O2 to ter-. minal 0. Relay O2 sticks up over its contact a, and relay OI releases, due to the opening of con- OR! to terminal C. Relay CRI closes its right tact c of relay Zl. The opening of contact a of relay ZP releases relay Tl, opening the line circuit to terminate the first impulse.

'Relay Tl upon releasing opens the circuit for relay TP at contact e of relay Tl,but relay TP- remains picked. up. The dropping of contacts I and 1 of relay Tl shifts the circuit for relayxl from the branch including the lower winding ofa relay 2! to the one including contact d of relay ZP and the lower Winding of relay Yl, thereby reversing relay Yl. Relay Yl then completes a circuit for selecting the character of the second impulse. This circuit extendsirom terminal B at contact 11 of switch HSI, over contact c of relay TP, contact g of relay Wl,contacts b of relays ZP, Yl and CRI, contact d of relay ISD, contact c of relay 02, wire 22, contact c of relay 1P, which contact, as assumed, now stands reversed, thence to wire J6, contact g of relay Tl through relay T2 to terminal 0..

Relay T2 picks up and supplies a Y impulse to. the line circuit, and completes a stick circuit from wire l8 over its own contact b contact b of relay Yl, and thence to terminal-B at contact b of' switchHSl. Contacts j and 7 of relay T2 pick up and shift the circuit through relay Xi from the branch including the lower winding of relay Yl to the one including contact d of relay Yl and hand contacts a and b to prepare circuits extending over contacts e and f of relay ISD and wires 26-32 'for selecting the character of the sixth to twelfth impulses, inclusive, The reversal of contact 0 of relay CR! prepares a circuit over contact I) of relay 06 for operating relay OI on the sixth step, and contact 11 of relay CRI prepares a circuit over contact g of relay 05 for operating relay Ol2'in place of relay O6on the eleventh step. It may be that some of the steps are not needed for control purposes, in which case the 7 corresponding wires as shown 'for wires -32 in Fig. 3B are connected directly to wire l5 so as to provide the X character for each'of these steps.

On the eleventh step relay Tl or T2 picks up over wire 3|, and relay 012 over contact I) of relay 05, and when relay O|2 picks up relay I ST is picked up over a circuit extending from terminal B at contact g of relay T3, contacts c of relays I SP and (M2 through the upper winding of relay IST and thence to terminal C over wire 13. Relay IST closes its contact a and thereby reestablishes its normally closed stick circuit, and opens its contact b to release relay l Relay Tl or T2 reverses relay Zl, relay Z] reverses relay the upper winding of relay Zi thereby operating ZP, and then relay Tl or T2 releases to operate relay Yl to re-reverse. Relay Tl or T2 then picks up over wire 32 to transmit the twelfth impulse, restoring relays Zl and ZP to normal, thereby releasing relay Ol2 and relay '11 or T2, which 7 then restores relay Yl to normal.

O3 sticks up over its contact a,- and relay O2 releases, due to the opening of contact d ofrelay Zl. The opening of contact b of relay ZP releases relay'T2, opening the line circuit to terminate the second impulse.

.Relay T2 upon releasing completes a circuit at its contact 7' over contact 0 of relay 2? to hold relay XI energized and to operate relay YI to normal. The closing of the normalcontact a oi relay Yl then completes a circuit for selecting the character of the third impulse. This circuit extends from terminal B at contact b of switch HSI, as already traced, to contact c of relay O3, thence over wire 23 to contact c of. relay 3]? to wiralecl5, and thence through relay TI to termin t Reviewing these operations, it be seen that the selector relay ISD and the first counting relay 0| pick up during the interval preceding the first impulse and complete a circuit. over wire 2| to pick up relay Tl. When relay Tl or T2 picks up over wire 2|, 23, 25, etc., to transmit an odd-numbered impulse, relay'Zl is operated to reverse to pick up an even-numbered counting relay O2, O4, O8,

etc., and to operate relay ZP to reverse to relay Tl or T2 whereupon relay Yl is operated to reverse to complete a new circuit iorrelay Tl or T2 over wire 22, 24, 28, etc. RelayTl or T2 then picks up,

to transmit an even-numbered impu1se,'and relay Zl is operated to normal to pick up the next odd-numbered counting-relay 03, 05, etc.,' and to operate relay Z? to normal, which releases, relay Ti or T2, whereupon relay Y! is operated to normal to complete, the next circuit over wire 23,

25, etc., thisprocess continuing step by step until the code is completed. When relay 06 picks up on the fifth step, relay CR1 reverses in response to the closing of the circuit from terminal B at Relays Ti and T2 now remain released, consequently relay TP releases, closing a circuit from terminal B over contacts a of relays TP and WI through the upper winding of relay CRI to terminal C, restoring relay CRI .to normal. The opening of contact b ofrelay TP releases relay L0, and relay L0 in turn releases relay XI The closing of contact b of relay L0 completes a'pick-up circuit for relay T3, which now becomes energized to supply a Z impulse to the line, that is to say, to restore the line circuit to its normal closed condition, whereupon relay L0 becomes reenergized over its upper winding. -Relay-T3 completes a stick circuit at its. contact a and so remains picked up after relay L0 is reenergized. The

the opening of contact 9 of relay T3 releases relays ISD and SIP. When relay L0 becomes reenergized, the closing of its contact c completes V switch control code is initiated by momentarily interrupting the normally closed starting circuit extending from wire l3 over certain lever contacts a to terminal C, to'release relay IST and to pick up relays ISP and ISD. The transmission of a. signal control code is eifected in a similar manner by momentarily interrupting the starting circuit extending from wire l4 over the back contact a of .relay T3, wire l8, contact c of relay 06 through the lower winding of relay contacts a of the signal levers SIG and of the call-on push buttons PB, to terminal 0. To clear,

signal 2RC, for example, lever 2S|G is pressed-to release the lever latch thereby opening its contact a to release relay 2ST, andfis then turned to the rightand released, theclosing oi'it's con- ,tact a completing a circuit over wire ",contacts b of relays 2ST and ISP, topick up relay 2SP-by energizing its upper over contact d of relay .SI'P. The closing of contact a of relay 2SP then energizes the upper winding of relay ST? Q opening of contact a of relay T3 extinguishes lamp CE and trol code being in other respects similar tothe switch code as described above in detail.

It may happen that the starting circuits over wires I3 and I ,6 are both opened at the same time while the system is at rest so as to release relays- IST and 2ST simultaneously. In this case relay ISP picks up and relay ZSP remains released due to the opening of its circuit by contact b of relay ISP, so that relay ISD becomes energized and a switch control code is transmitted. Relay IST is reenergized on the eleventh step of the code releasing relay ISP as already described. When relay T3 picks up atthe end of the code, relay 2SP picks up over the circuit from terminal B at contact 2 of relay T3 over contact 5 of relay ISD through the upper winding of relay 281 and over contacts b of relays ISP and 281 and wire It to terminal C. The stick circuit for relay STP is opened at contact 9 of relay T3 at the same time, but relay 2ST picks up quickly closing its contact a to energize, relay STP in series with its lower winding so that relay STP :remains picked up. Relay ISD releases due to the opening of contact 9' of relay T3; relay Lil pick up and reenergizes relay WI, whereupon relay Tl? picks up to release relay T3, which picks up relay 28D to initiate a signal control code.

'It will be seen therefore that a code started by opening wire I3 takes precedence over one started by openingwire it, if both starting circuits are opened at the same time while the system is at res Assuming that a switch lever is operated during the transmission of a switch control code but that no signal lever is operated so that relay 2ST remainsenergized, it will be seen that relay iSP will be released by the momentary opening of the starting circuit over wire it while the switch control code is in progress so that relay 5ST will not become reenergized on the eleventh step, due to the opening of contacts of relay ESP. In this case, when relay T3 picks up at the end of the code, the-opening of its contact g releases relays STP and ISD, and relay ISP picks up over con-.

tact b of relay SIP, and is then held, energized and relay STP is reenergized over contact a of relay ISP. Relay T3 energizes relay L6 which picks up relay WI "and then relay TP picks up over contact 0 of relay STP releasing relay T3 to pick up relay ISD to initiate a second switch control code.

Two codes stored by the release of relay lST will thus be transmitted successively only if relay 2ST is not released, and similarly, two codes stored by the release of relay 2ST will be transmitted successively only if relay IST isnot released. Ii thestarting circuits over wires i3 and ticular element in either group to the time required to transmit one code.

The switch control code just described may be repeated at a slow rate for test or observation y reversing the manually operable switch HSI and then operating the push button ISTB momentarily to release relay IST. Relays ISP, STP and TP then pick up as already described, relay TP completing a stick circuit at its contact e extending'to terminal B over contacts a of switches HSI and H82, and then relay T3 releases and relays XI, OI and ISD pick up and relay WI releases in the normal manner, the closing of contact 9 of relay WI preparing a circuit for relay TI, extending to terminal B over contacts b of switches HSI and H52. The line circuit therefore is opened by. the release of relay T3, and is closed by operating switch I-IS2 to pick up relay TI. Relay TI by closing its contact e completes a stick circuit for relay TP and reverses relay ZP. Relay ZP opens the pick-up circuit for relay TI but relay TI is now held energized over a stick circuit including its contact a and contact b of switch H82 and remains picked up until switch H52 is manually released, whereupon the stick circuit for relay TP including its contact e is reestablished. The code therefore may be trans- ,mitted step by step by repeatedly operating switch H82. Relay 0I2 releases on the twelfth step, and consequently the thirteenth operation of switch H82 fails to 'pick up relay T I or T2, consequently relay TP releases and in turnreleases relay L0 to complete the pick-up circuit for relay T3 extending to terminal B at contact h of relay T2. Relay T3, closes the normal line circuit, restoring the apparatus to normal in the usual manner, whereupon switch HS2- may be released.

When relay WI picks up. if a second code is stored for transmission so that contact 0 of relay STP is closed, relay TP will be reenergized opening the normal stick circuit for relay T3, but relay T3 is held energized until switch H82 is released due to the provision of an auxiliary stick It are interrupted repeatedly to'eflect the transmission or a series of codes, the two codes will alternate, due to the operation of contacts I) of relays 'ISD and 28D. In this case, relay STP circuit including contact I of relay WI.

1' shall now explain how the above described switch control code is received by the station receiver of Fig. 2.

When the line circuit is initially opened by the release of relay T3, relay L3 releases, its contact at opening the normally closed. circuit including the upper windings of relays W2, ICD, 2CD, CR2 and Z2, and its contact b closing a circuit through relay X2 over contacts b of relays -LI and L2, contact a and the lower winding of relay W2 and the upper winding of relay Y2 to terminal C, whereby relay X2 is picked up, relay W2 held energized and relay Y2 held normal. The closing of contact 0 of relay X2 completes a circuit from terminal 13 at contact 11 of relay L3 over contacts 0 of relays X2, Z2, W2 and CRP through relay I to terminal C. Relay I picks up conipleting a stick circuit at its contact a.

The first impulse of the code being of the X character, current flows from the positive terminal of battery over contact d of relay TI and line X through both windings of line relay LI from leftto right and through both windings of line relay L2 from right to left, to line Y and thence over contact 0 of rela TI to the negative terminal bottery 80, consequently relay LI picks up, closing its contacts a and. 0 while relay L2 remains released. Relay LI completes a circuit from terminal B at its contact o over contacts 0 of relays Y2 and I,wire SI, contact '12 of relay CRP, through the lower windings oi relay I CD and 2CD, reversing relay l CD and holding relay 2CD normal. The opening or contact b of relay Ll releases relay W2. The closing of contact a of relay Ll completes a circuit from terminal B at contact b of relay L3 including the winding and front contact a of relay X2, contacts a of relays LI and Y2 through the lower winding of relay Z2to terminal'C, holding rela X2 energizedand reversing relay Z2. Relay Z2 completes a circuit from terminal 13 at contact (1 of relay L3 over contact of relay X2, contact d of relay Z2, contact I) of relay I through relay 2 to terminal C. Relay 2 picks up, completing a stick circuit at its contact a, and'relay l releases in response to the opening of contacts 0 of relays W2 and Z2.

Relay Ll releases upon the termination of the first impulse, its contact 11 opens and its contact it closes to shift the stick circuit for relay X2 from the branch including relay Z2 to one extending over contacts 11 of relays Ll, L2 and W2, contact 12 of relay Z2 through the lower winding of relay Y2 to terminal C, thereby reversing rent now fiows from the positive terminal of batposition of contact 0 of relay IP of Fig. 3B, curtery 80 over contact d of relay T2 to, line Y, and

thence through both windings of relay Ll from right to left, and through both windings of relay L2 from left to right, to line X and over contact 0 of relay T2 to the negative terminal of battery 80, consequently relay L2 becomes energized, relay LI remaining released. Contact a of relay L2 closes and its contact (1 opens to shift the circuit for relay X2 from the branch including relay Z2 to one extending over contact b of relay Y2 of relay Y2 to terminal C at contact 0 of relay L2. Relay IWS is thereby operated to reverse, provided the switch locking relay ILR is enered, relay ILR being controlled by the interlocking circuits of Figs. 4A and 4B in such a manner that it is energized only when trafiic conditions are proper for the operation of th track switch IW.

The operation of relay Z2 to normal completes a circuit from terminal B at contact d of relay L3 over contacts 0 of relays X2 and Z2, contact b of relay 2 through relay 3 to terminal 0, so that relay 3 picks up establishing a stick circuit at its contact a. The opening of contact (1 of relay Z2 releases relay 2, which relay by opening its contact c terminates the impulse delivered to relay IWS.

Relay L2 releases upon the termination of th second impulse, its contact :1 opens and its contact d closes to shift the circuit for relay X2 from over contact a of relay Z2 through the upper winding of relay Y2 to terminal C, thereby operating relay Y2 to normal.

The third impulse is of the X character, like the first, except' that in this case its character corresponds with the normal position of contact c of relay SF of Fig. 3B, and consequently relay Ll becomes energized in the same manner as on 'shown in the drawings.

the first step already described, completing a circuit over its contact a and contact a of relay Y2 as on the first step to reverse relay Z2. The closing or contact 0 of relay Ll on the third step completes a circuit from'terminal B over contact c of relay Y2, contacts a of relays I CD, CR2, contact c of relay 3,'wire 63 through relay IWS. Fig. 4C, thence over contact b of relay HR to terminal 0, thereby checking relay 3W in its normal described, it will be seen that the first countin relay I picks up in the interval preceding the first impulse of the code and prepares a circuit over wire 6| to reverse the delivery relay ICD if the first impulse is an X impulse to' which relay Ll responds, and relay ICD prepares circuits over wires 62-42 to operate a group ofstick polar relays to normal or reverse in accordance with the X or Y character of the remaining impulses. Similarly, if the first impulse is of the Y character, as in the case of a signal control codeinitiated by releasing the office storage relay 2ST, relay L2 responds to the first impulse to reverse relay 2CD to prepare circuits over wires 82-92 to operate a second group of stick polarrelays such as the signal control relays 2LI-IS, ZRHS, 2COS, etc., 0f Fig. 40, in accordance withthe character of the remaining impulses.

- When relay LI or L2 picks up in response to an odd-numbered impulse relay Z2 reverses and picks up an even-numbered counting relay 2, 4,

6, etc., relay Yl reversing when relay Ll or L2 LI or L2 restores relay Z2 to normal to pick up an odd-numbered counting relay 3, 5, etc., and relay Y! is restored to normal when relay Ll or L2 releases. Relays CR2 and CRPare reversed by the closing or contact 0 of relay 6 on the fifth step, contact 0 of relay CRP preparing a circuit tact 'd of rela CR2 preparing one for operating relay l2 on the eleventh step, the countingrelays operating through two cycles like the correspond leasing relay l2, and'when relay Ll or L2 releases, relay Y2 is operated to normal.v

A reset impulse of the Z character follows th final code impulse,- energizing relay L8, The

opening of contact b of relay L3 releases relay X2, and the closing of contact a of relay L3 picks up relay W2 and operates relays ICU and CR2 to normal and holds relays 20D and Z2 normal. Relay CR2-restores relay CRP to. normal, the receiving apparatus then being in the condition In the foregoing I have explained how the various polar stick control relays are controlled by the code apparatus of Figs. 1 and 2 over sequentially established communication channels all including the same line wires X and Y, and since the branch including relay Z2 to one extending the indication system employs similarapparatus it will be understood that the polar stick indication relays of Fig. 3A are similarly'controlled that .the sequentially established code channels may be replaced by separate direct wire connections, this being the usual practice for the control of. a zone in the immediate vicinity of. the

The code transmitter and receiver at the station are so arranged that each control code is followed by the transmission of an indication code by the station transmitter. The reversal of relay lCD by the first impulse of the control code just described opens its contact d, which is included in the starting circuit for the station transmitter as shown in Fig. 4A. Consequently the station relay IST, Fig. 1, releases on the first step of the control code, and the closing of contact d of relay ICD during the reset impulse following the control code picks up relay ISP to initiate the indication code.

The reversal of relay IWS by the control code reverses the switch operating relay IWR, Fig. 4C, for the switch machine ISM, thereby operating switch IW to reverse, contact b of relay IWS opening the normal switch indication circuit including relay IWP and INWP, Fig. 4A, and preparing a circuit for energizing relay IRWP when the switch machine ISM completes its operation and locks switch IW in its reverse position.

' These indication circuits are of the type disclosed in a pendinga'pplication for Letters Patent of the United States, Serial No. 465,183, filed November 12, 1942, by Arthur E. Dodd, for Electrical control apparatus. the control code will be followed by two indication codes. The first is initiated by the operation of contact d of relay iCD when relays INWP and iRWP are both released to connect wires 22 and 23 over back contacts 0 of these relays to wire l6, as shown in Fig. 4A, so that the second and third impulses of the first indication code are Y impulses. The ofilce receiver is consequently condi tioned to supply impulses of reverse polarity over wires 62 and s3, Fig. 3A. The circuit for the second impulse including wire 62 is open at the left-hand contact b of relay iP, which stands open under the conditions assumed. The circuit for the third impulse is completed from terminal relay lRWP is connected to wires l5 and 23, relay IWK is operated to normal over wire 63 to complete a circuit at its contact b to reenergize relay iWC, thereby extinguishing lamp iWE, and preparing a pickup circuit for relay ZRH.

I shall now describe the operations involved in the transmission of a control code for clearing signal 2R0. Noting that the switch leverlamps IWE and 3WE are both dark, indicating that a route corresponding to the positions of levers ISW and SSW is established, the operator moves lever 285G to its right-hand position to" initiate a control code for clearing signal '2RC. The opening of contact a of lever 2SIG releases relay It will be evident that 2ST, and the subsequent closingof this contact when the lever is released effects the energize.- tion of relays 2SP, ST? and TP, and relay TP releases relay T3 to pick up relay 2SD, as hereinbefore described. The closing of contact c of lever lslG'energizes. the lever repeating relay ZRP, which relay completes a route circuit extending in Fig. 3A from terminal B atcontact g of relay 2L? over contact b of relay ZNK, contacts a of relays 3PP, 3W0, IWC and ZNK, contact c of relay 2RP through the route relay 2RI-I to terminal C. Relay ZRH picks up and completes a circuit for lighting the red lamp 2GE associated with lever 2SIG, extending from terminal B at contact d of relay 2GKS over contact (2 of I relay 2GK, contact 0 of relay 2RH and the righthand contact d'of lever ZSIG through lamp EGE to terminal C. Relay ZNK, Fig.'3A, is now operated to reverse over the circuit including contacts b of relays 2RP and ZRH and by he operation of its contacts a and cdisconnects relay 2RH from the route circuit network and holds relay ZRH energized over a stick circuit including its own front contact a and contact 0 of relay 2NK. Relay 2RH also prepares a circuit in Fig. 33 from wire I6 over front contacts d of relays ZRH and ZRP to wire t3 so that the third impulse of the resulting signal control code operates relay ZRHS, Fig. 4C, to reverse over wire 83.

The reversal of the signal control relay ZRHS opens its contact 0 in the circuit for relay ZRAS, Fig. 4B. These approach locking stick relays RAS and LAS are controlled in the manner disclosed in Letters Patent of the United States No. 2,198,712, granted Api'il 30, 1940, to Harry C. Vantassel, for Railway tramc controlling apparatus. Relay ZRAS therefore releases, opening its contact b in the circuits for the switch locking relays 51R and SLR to lock the switches for routes over which trafilc movements are governed by the signals which relay ZRHS controls. Relays HR and SLR. therefore release, closing their back contacts 1 in the signal network comprising the upper portion of Fig. 48, to complete a circuit for mechanism ZRCG which extends from terminal B at front contact (I of relay ZLAS over contact 7 of relay 31R, contact b of relay t'NWP, contact ,f of relay ILR, contact b of relay iRWP, back contact d of relay ERAS, reverse contact a oi relay ZRHS, normal contact a of relay ZCOS, contact 6 of relay BNWP, contacts b of the track relay BTR and the track stick relay ITPS, the

reverse contact a of relay iWP through mechanism ZRCG and over the reverse contacts 02 of relay IWP and b of relay 2RHS to terminal C. Mechanism ZRCG thus becomes energized to clear signal 2R0 and to release the signal indicating relay ZRGP shown in the lower portion ,of Fig. 4B.

By reference to Fig. 4A it will be seen that the operation of relay ZCDand the release of relays 'ZLAS, ILR, 3LR and ZRGP will interrupt the circuits over wires l8 and M to initiate two and possibly three indication codes in response "to which the lock indication relays ILK and 31K, Fig. 3A, are operated to reverse over wires 85 and 61,.relays IWK and 3WK are checked normal over wires 63 and B5, relay INK is checked reverse over wire 82, relays GNK and QGK are checked normal over wires 84 and 85, and relay EGK is operated to reverse over wire 88. The opening of contacts a of relays ILK and 31K locks relays IWK and BWK. normal, and thereby locks relay IP reverse and relays 3P and 31?? normal, rendering these relays non-responsive to the operation of levers ISW and 38W. It now lever ISW is inadvertently operated or if the track switch should become displaced or unlocked mechanically by the switch machine ISM- extends from contact a of a flasher r'elay CT over contact 9 of relay IWC and the normal contact d of relay l WK, or over the reverse contacts d of relays ILK and [WK through lamp IWE to terminal C.

It will be seen therefore that if a switch lever is moved or a track switch becomes displaced when it is not locked electrically; its relay LR being energized, a steady light will be displayed by the lamp WE associated with the lever, but if its relay LR standsreleased at the time a flashing light will appear to inform the operator that the 'switch cannot be operated and if this is due to a lever movement that the lever should be returned to its original position.

It will also be seen that when the track switches are locked electrically their control relays WS are rendered non-responsive to control code impulses, due to the opening of contacts b of the relays LR. The switch control circuits thus include a non-storage feature whereby the switch control relays are rendered responsive to the operation of their respective levers only if the levers are operated at a time when the track switches are free to respond. Switch control codes however may be freely transmitted including the elements assigned to the control of the electrically locked switches for the purpose of operating other track switches or for other purposes to control relay MCS, for example.

The reversal of the signal indication relay 2GK completes a pick-up circuit for relay 2GKS, Fig. 3B, extending from terminal B at contact f of relay ZRP over contact a of relay ZGK through relay ZGKS to terminal C, relay ZGKS picking up and completing a stick circuit at its contact a. Relay ZGK also extinguishes the red lamp 2GE by opening its contact and completes a circuit for lighting a green lamp 2RCE, Fig. 3A, for illuminating the representation of signal 2R0 on the track diagram, this circuit extending from terminal B at contact 12 of relay 2GK over contact f of relay 'ZRH, contact 0 of relay IWK, reverse contact b of relay IP through lamp 2RCE to terminal C.

The circuits including wires I3 and M by ,which the above described indication codes are initiated differ in one respect from those at the oflice as described in connection with Fig. 1, as willnow be pointed out. Since the initiation of the codes is dependent upon the integrity of these circuits. which are more susceptible to failure because of the number of contacts in series, emergency connections to terminal C over wires l1 and I 8 are provided. If, for example, one of the indicating relays such as relay 2RGP opens its front contact a to release relay 2ST, Fig. 1, and if due to a fault the closing of its back contact (1 fails to reestablish the connection to terminal C to pick up relay 2SP. the transmitter which otherwise would be unable to function, is set into operation by picking up relay 2SP over the connection from wire '4 to wir'e l8, contact d of relay 2ST to terminal C at contaoty' of relay 28D. Since this connection includes back contact (I of relay 2ST it does not provide a circuit for holding relay 2ST energized, consequently it causes the code initiated by relay 2ST to be transmitted repeatedly, with codes initiated by relay I ST interposed at intervals whenever the circuit over wire I3 is momentarily opened, until the fault is corrected, thereby enabling the system to be kept in operation.

I shall next assume that the approaching train governed by signal 2R0 enters section IT. This releases the track relay I'IR, which in turn releases relays I'I'P and ITPS. The opening of contact b of relay ITPS opens the circuit for mechanism 2RCG, restoring signal 2R0 to stop, and reenergizing relay 2RGP, and. an indication code is initiated in response to which relay ITK is operated to reverse over wire 86 to light the red lamp ZTKE in the track diagram and relay 2GK is operated to normal over wire 83. Relay 2GK extinguishes the green lamp 2RCE, and com pletes a circuit for flashing the red lamp 2GE, extending from contact a of the flasher relay CT over contacts 0 and d of relay ZGKS and 2GK, contact 0 of relay 2RH, contact 11 of lever ZSIG v through lamp 2GE to terminal C. Lamp 2GE is thereby supplied with interrupted current and continues to flash until lever 2SIG is restored to normal.

If the train new vacates section lT, the enerreversed.

The operator now restores lever ZSIG to nor,-

mal, releasing relays ZRP and ZGKS, thereby lighting lamp ZGE steadily over the circuit extending from terminal B at contact d of relay 2NK over the middle contact (1 of lever 2SIG to terminal C, and initiating a signal control code in which wire 43 is connected over contact h of relay 2RP to wire I5 to operate relay 2RHS, Fig. 4C, to normal over wire 83. .Relay ZRAS then picks up over the circuit extending from terminal B at contact 0 of relay 2RHS, contact d. of relay ZRGP, contacts c of relays I'I'PS- and 2008 through relay ZRAS to terminal 0, relay 2RAS 1 completing a stick circuit at its contact e. Re-

-lay ITPS now picks up over contact f of relay ZRAS, and relays ILR and 3LR pick up over contact I) of relay ZRAS, provided section IT has been vacated so that contact e of relay ITR. is closed. Relay 2RASinitiates an indication code in which wire 42 is connected to wire l5, causing" relay 2NK, Fig. 3A, to be restored to normal over wire 82, and relay ZNK by opening its contacts 0 and it releases relay ZRH and extinguishes lamp 2GE.

The energization of relays ILR and 3LR initiates an indication code restoring relays ILK and 3LK to normal. If lever 2SIG is restored to normal while section IT is occupied, this code will be transmitted when the section becomes vacated and will include the impulse for extinguishing lamp ITE, indicating that levers ISW and 38W are again free to be operated.

It will be seen that if a signal lever is'moved from normal to right or left when the switches in the route correspond in position with their switch levers and no conflicting route is set up, a steady red light will be displayed by the lamp GE associated with the lever, which will become dark and a green light will be displayed at the signal loca tion in the track diagram when the signal clears. If the lever is reversed when these conditions are not met, or if the signal is put to stop by train movement, a flashing light is displayed by lamp GE until the signal lever is restored to normal.

I shall now assume that signal ZRC has been cleared as above described and that the operator desires to restore it manually to stop to set up a difierent route, such for example, as the one governed by signal 2RC which extends over switches 3W and 3AW reversed. The operator will first restore lever ZSIG to its normal center position, releasing relays ZRP and ZGKS. The green lamp ZRCE remains lighted, and the red lamp ZGE becomes lighted over the normal con-. tact d of lever ZSIG, and a signal control code is transmitted as before, to restore relay ZRHS to normal. Mechanism 2RCG is thereby deenergized to put signal ZRC to stop, and relay ZRGP becomes reenergized to initiate a code to restore relay ZGK to normal, thereby extinguishing lamp 2RCE.

The reenergization of relay 2RAS is delayed by the operation of the time looking, the closing of contact of relay ZRHS and contact at of relay ZRGP completing a circuit for a thermal relay 2RTE, which after a suitable time picks up a stick relay ZTES, deenergizing relay ZRTE, which then returns to its normal condition after a further time interval to complete a pick-up circuit for relay 2RAS including contact b of relay 2RTE and contacts 0 and d of relay 2TES. Relay 2RAS then picks up, reenergizing relays ILR and 31B,- and initiating a code to restore relay 2NK to normal. thereby releasing relay 2RH and extinguishing lamp ZGE. Relays ILR and 3LR initiate a second indication code to restore relays lLK and 3LK to normal.

The operator now reverses lever 38W, initiating a switch control code in the manner hereinbefore described to reverse switches SW and SAW, lamp SWE becoming lighted in response to the lever operation and extinguished upon the receipt of an indication code indicating that switches SW and SAW are mechanically locked reverse.

The operator then operates lever 251G to the right, the operations difiering fromthose already described only in that relay ZRH is now picked up over the route circuit which extends to terminal B over the reverse contact a of relay 3PP. contact b of relay flNK and contact g of relay 6L1, and mechanism 2RCG is energized over the corresponding circuit in Fig. 43 extending to terminal B at front contact d of relay dLAS and including contact g of relay SLR, contacts b of relays SRWP and 3TP and contacts a of relays -GL'I'R. and 3W1.

It will be seen from Fig. 3A that relays HRH and a iLH are now rendered non-responsive to the operation of lever fiSIG, even though lever ZSIG is restored to normal, for the reason that contact b of relay SPP and contact a of relay 2NK are open,

and if lever tSIG is now moved to the left or right, lamp liGE will be caused to flash due to the closin of its circuit over back contact g of relay QLH or tRH, in Fig. 33, indicating that none of the routes governed by lever GSIG are available.

If one or more of the track sections IT, ST or 4LT of the route just described are occupied by a train, the call-on signal 2RD may be cleared to permit a second train to enter the route. To clear signal 2RD, the operator leaves or places lever :5 locking which governs the transmission of codes 2SlG in its right-hand position so that relay 4 provided section 55 to the 2RP and ZRH will beenergized .to operate relay 2RHS to reverse, and then presses button ZPB momentarily to pick up relay 2C0 over the circuit from terminal B at contact 1 of relay ZRP 6 through relay 2C0 and over contact b of button 19 2008, Fig. 40, to be operated to reverse over the connection from terminal B over contacts b of relays 2LGP and 2RGP through relay 2COS to wire 84 and thence in Fig. 2 to terminal C at contact 0 of relay L2. The closing of the right-hand con- 16 tact a of relay ZCOS in the signal circuit network.

Fig. 4B, completes a circuit for energizing mechanism 2RDG, which circuit is similar to the one for mechanism 2RCG already traced, except that it does not include contacts of the track relays for 20 the route. Signal 2RD is thereby cleared and relay 2RGP releases to initiate an indication code. thereby reversing relay ZGK to extinguish lamp 2GE and to light lamp ZRCE, the same as when the proceed signal 2R0 is cleared.

To put the call-on signal to stop, the operator restore lever ZSIG to normal, thereby releasing relays 2RP and 200, and initiating a control code which restores relay ZRHS to normal. Wire 84 is now connected to wire l5 over contact d of reIay ZCO so that an X impulse is transmitted over the channel assigned to relay 2COS, the

circuit forwhich is open at contact b of relay ZRGP. Signal 2RD is put to stop by the operation of relay ZRHS to normal thereby reener- 5 gizing relay ZRGP. It is to be noted that with relay 2C0 released, control code transmitted after relay 2RGP picks up are not effective to restore relay 2008 to normal because relay Ll picks up on the assigned step and connects terminal B to wire 86, which merely establishes the same potential at both terminals of relay 2005, The closing of the normal contact 0 of relay ZRHS completes a pick-up circuit for relay 2RAS. IT of the route is still occupied. over contacts c of relays ITPS and ITR, reenergizing relay ZRAS, which relay restores relay ZCOS to normal by completing a circuit from terminal B over contacts g of relays ZRAS and 'ZLAS, Fig. 40, through the lower winding of relay 2COS to terminal C. If the call-on signal 2RD is restored manually to stop while section IT is unoccupied, relay 2RAS can be picked up only at the end of the time locking period, duo provision of contacts 0 of relays 2COS and ITR in the release circuit for relay 2RAS which includes contact 0 of relay ITPS. Without this provision it would be possible to put sig- It will be noted that when a signal has been cleared, it cannot be put to stop inadvertently by the operation of any lever other than its control lever, nor by the operation of a call-on push -button, although the clearing of the signal as .efiected through the route circuits of Fig. 3A

the position of the switch is dependent upon lever for each switch of the route and of the signal lever for th opposing signal for the route. Furthermore, the time and approach ceived by said for operating the track switches also governs the transmission of signalcontrol codes for reversing the direction of trafllc movements over a route. It will also be noted that a repetition of a code for clearing a signal which has been put to stop by a train is efiective only if it is the result of a second operation of the signal lever.

In the foregoing I have described-but a few typical operations of the control system, but as the remainder are carried out in af manner similar to those described, it is believed that they will be understood without further explanation.

Although I have herein shown and described only one form of remote control system 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 my invention.

Having thus described my invention, what I claim is: v

1. In a remote control system, a code transmitter and a receiver, each including a chain of counting relays, three line wire connecting said code transmitter and receiver, three line relays for controlling the'receiver each selectively responsive to current of a given polarity only transmitted over the corresponding one of said line wires from a source adjacent said transmitter and returning to said source through the winding of another of said line relays and the line wire corresponding thereto, one of said line relays being normally energized by current from said source, a fourth line relay for controlling the transmitter normally energized in series with said source and said one line relay, a starting .circuit effective only when said fourth line relay is energized for initiating the operation of the transmitter, means controlled by the transmitter when initiated for energizing the transmitter counting relays one at a time in order, and for disconnecting said source from. one line wire to maintain said one line relay and said fourth line relay deenergized while supplying a series of impulses of current from said source of either polarity to the other two line wires in series to selectively operate the other receiver line relays in accordance with the relative polarity of said impulses, means controlled by said one line reaacaaae two-oi which are normally energized by current from said source of the same polarity, said current having a return path including the third line wire, a transmitter efiective when initiated to disconnect said third linewire from said source' and to then transmita series of impulses of current of normal or reverse polarity from said source over a circuit formed by said two line wires, 9.

receiver including a chain of counting relays and a line relay selectively responsive to the current in said third line wire, .means responsive to the release of said line relay for energizing the first relay of said chain, means responsive to impulses transmitted over said two line wires for energizing each ,succeeding'relay oi the chain, means including a back contact of said line relay for holding each counting relay energized only until the next succeeding relay 0! the chain is energized, a series of control relays of the stick polar type, and means controlled by said counting relays ior operating'said polar stick relays successively to normal or reverse each in accordance with the relative polarity of a different impulse of said series.

4. In a remote control system, a source of current, two line wires normally energized by current of the same polarity supplied from said source lay when deenergized 'for rendering the receiver counting relays responsive to the impulses reother line relays, a plurality of control relays, and means controlled by the re-- ceiver counting relay responsive to the relative polarity of a different one of said impulses.

2. In a remote control system, a three wire linev circuit normally energized by current of a given polarity transmitted over one of the linewires and returning overthe other two line wires in parallel, a chain of counting relays adapted to be operated one at a time in sequence in response to a series of current impulses, a line relay responsive only to current 01' said given polarity transmitted over said one line wire, a circuit closed in response to the release of said line relay for operating the first relay of said chain, and means responsive to a series of impulses transmitted over a two wire circuit comprising said other two line wires only and eflfec'tive only so long as said line relay remains released for op-' erating each succeeding relay of said chain,

3. In a remote control system, a source oi current, a line circuit comprising three line wires over a third line wire, a receiver including a line I relay responsive to said current, a code transmitter effective when initiated to temporarily disconnect said source from said third line wire and to then connect said source reversibly to said two line wires to thereby transmit a series of impulses of the opposite polarity over one or the other of said two line wires while thethird wire is deenergized, a chain of counting relays controlled by said receiver, means controlled by said line relay in its released position for operating the first relay oi the chain effective only when the operation of said code transmitter is initiated, pick-up circuits controlled by said receiver for operating the remaining relays of the chain one at a time in order to count the received impulses,

stick circuit for each counting relay, said pickup and stick circuits including contacts closed by the line relay in its released position, and

means controlled by said transmitter for ener gizing both line wires by said current of the same polarity to reenergize said line relay following the transmission of a predetermined number of impulses.

5. In a remotecontrol system a line circuit comprising three line wires two oi nich are normally energized by current of the same polarity, said current having a return path including the third line wire, a transmitter effective when initiated to transmit a series of impulses of normal or reverse polarity over a circuit formed by said two line wires, a chain of counting relays for controlling the transmission of said impulses. a line check relay responsive to said impulses and also to current in said third line wire, means for locally energizing said line check relay during a receiver including a line relay selectively responsive to the current in said third line wire, means responsive to the release of said line relay for rendering the receiver responsive to said impulses, and means responsive to the release 01 said line check relay for again supplying current of the same polarity to said two line wires.

I pulses of 7 line check relay energized during line check relay, a code receiver including three line relays, a line circuit comprising three 'line wires two of which are normally energized by current of the same polarity over front'contacts of the first of said transmitter relays, said current having a return pathincluding the first of said line relays and said line check relay, means dependent upon the continued energization of said line check relay and comprising the second and third transmitter'relays for transmitting imnormal or reverse polarity over a circuit including said two line wires, said second and third line relays and said line check relay, a local circuit including back contacts of said second asaasss 9. In a remote control system, a line circuit, a transmitter for delivering impulse codes to said line circuit, two groups of indicating relays, a storage relay, a repeating relay and a selector 6 relay for each group, a normally closed stick cirand third transmitting relays for maintaining the I the intervals between successive impulses, a receiver conditioned by the release of said first line relay to respond to the impulses received by said second and third line relays, and means for reenergizing said first transmitter relay after the transmission of a predetermined number of impulses.

'7. In a remote control system, a, line circuit, a code transmitter including three transmitter relays for controlling said line circuit, a slow release transmitter check relay for controlling said transmitter relays, an energizing circuit for Y the first transmitter relay including a back contact of said transmitter check relay, starting means for'at times momentarily energizing said transmitter check relay, circuits including a front contact of said transmitter check relay for selectively and repeatedly energizing said second and third transmitter relays to deliver a series of impulses of selected character to said line circuit, and a stick circuit for said transmitter check relay completed upon the energization of either said second or third transmitter relay for intermittently energizing said transmitter check relay to maintain it picked up during the transmission 01 said series of impulses.

8. In a remote control system, a line'circ'uit, a transmitter for delivering impulse codes to said line circuit, two groups of indicating relays, a storage relay,'a repeating relay and a selector relay for each group, a normally closed stick circuit for each storage relay including contacts of each indication relay of its group, arranged to open the circuit momentarily in response to a change in position of such relay, pick-up and stick circuits for each repeating relay including a back contact of its storage relay and said contacts of the indication relays of its group, said pick-up circuits also including a contact closed. only when the transmitter is in a normal at rest condition, and the circuits for one repeating relay including a back contact of the other, circuits closed by each repeating relay when energized for energizing the associated selector relay and for initiating the delivery of a code by said transmitter including impulses for indicating the positions of the indicaton relays of the corresponding groupga code receiver controlled over said line circuit and responsive to such code,

a means including said indication relay contacts for releasing the energized repeating relay without interrupting the code if a change occurs in the position of any of such indication relays during itstransmission, and means for returning said transmitter to its normal at rest condition at the end of the code comprising a pick-up circuit for each storage relay including a front contact of the associated repeating relay.

cuit for each storage relay including contacts of each indication relay of its group, arranged to open the circuit momentarily in response to a change in position of such relay; pick-up and stick circuits for each repeating relay including a back contact of its storage reiay and said contacts of the indication relays of its group, said pick-up circuits also including a contact closed only when the transmitter is in a normal at rest condition, and the circuits for one repeating relay including a back contact of the other, circuits closed by each repeating relay when energized for energizing the associated selector relay and for initiating the delivery of a code by said transmitter including impulses for indicating the positions of the indication relays of the corresponding group, a code receiver controlled over said line circuit and responsive to such code, means including said indication relay contacts for releasing the energized repeating relay without interrupting the code if a change occurs in the position of any of such indication relays during its transmission, .a pick-up circuit for each storage relay including a front contact of the associated repeating relay, and a pick-up circuit for each repeating relay including a back contact of the associated storage relay'and a front contact of the selector relay associated with the other storage relay, rendering said repeating relays efiective to initiate codes for indicating the condition of said two groups of indicating relays alternately in the event of repeated changes in the condition of such relays.

10. In a remote control system, a line circuit, a transmitter for delivering impulse codes to said line circuit, two groups of indicating relays, a storage relay, a repeating relay and a selector relay for each group, a normally closed stick circuit for each storage relay including contacts of each indication relay of its group, arranged to open the circuit momentarily in response to a change in position of such relay, pick-up and stick circuits for each repeating relay including a back contact of its storage relay and said contacts of the indication relays of its group, said pick-up'circuits also including a contact closed only when the transmitter is in a normal at rest condition, and the circuits for one repeating relay including a back contact of the other, circuits closed by each repeatingrelay when energized for energizing the associated selector relay and for initiating the delivery of a code by said transmitter including impulses for indicating the positions of the indication relays of the corresponding group, a code receiver controlled over said line circuit and responsive to such code, means including said indication relay contacts for releasing the energized repeating relay without interrupting the code if a change occurs in the position of any ofrsuch indication relays during its transmission, a pick-up circuit for each storage relay including a front contact of the associated repeating relay and said contacts of the associated indicating relays, and an auxiliary energizing circuit for each repeating relay including back contacts ofv the associated storage and selector relays for effecting its energization in the event of a failure of its normal energizing circuit including said indicating relay contacts.

11. In a remote control system, an oflice and a relay.

station connected by a line circuit, a group of indicating relays, a storage relay, a repeating relay and a selector relay at the station, a transmitter at the station for delivering an impulse code tosaid line circuit for indicating the positions of said selector and indication relays, receiving means at the ofiice responsive to said code, a start .ing circuit which normally provides a stick cir- 12. In combination with a section of railway track having a, track relay, a signal for governing the movement of tramc into said section, a signal control relay of the stick polar type, a normally energized approach locking relay associated with said signal, energizing circuits for said approach storage relay and of the selector looking relay including a normal contact of said signal control relay and an indication contact closed only when the signal indicates stop, a track stick relay having a pick-up circuit including a front contact of said approach locking relay and a stick circuit including a front contact of said track relay, and an energizing circuit for said signal including a reverse contact of said signal control relay, a back contact of said approach locking relay stick relay.

13. In a; system for controlling traffic movements over a railway track layout provided with I track switches for forming difierent trafllc routes and interlocked with signals controlled by tramc conditions for governing traiiic movements over such routes; switch levers, signal levers, and a normally inactive code transmitter controlled by said levers for controlling said switches and signals; a switch storage relay and selector relay, a'

signal storage relay and selector relay, means responsive to a change in position of any switch lever or of any signal lever for actuating the switch storage relay or the signal storage relay, respectively, means controlled by the switch stornd a front contact of said track age relay when actuated for energizing the switch selector relay and for initiating the transmission of a series of impulses selected thereby each adapted to operate a different track switch to a position corresponding to that of its switch lever, means controlled b trafllc conditions for preventing the reception of each such impulse except when the corresponding switch is free to be operated, means controlled by the signal storage relay when actuated for energizing the signal selector relay and for initiating the transmission of a series of impulses selected thereby each adapted to operate a diiierent signal to a posit-ion corre-.

sponding to that of its signal lever, and means for preventing the response of each signal to its code impulse in the event such. signal has responded to a similar impulse in a preceding code and its condition has then been changed due to a change in traflic conditions in said layout.

14. In a system for controlling traflic movements over a railway track layout provided with track switches for forming difierent trafilc routes and interlocking with signals for governing traffic movements over such routes, switch levers and signal levers for manually controlling said switches and signals, an indication relay of the stick polar type controlled by each signal, a route relay for each signal having a stick circuit including a reverse contact of the associated indication relayya route circuit network including a circuit for each route through the track layout extending between normall closed contacts of the indication relays for the opposite ends of the route and including contacts controlled by each switch of its route which are closed only when the switch is in the position required for such route and in correspondence with its switch lever, each such indication relay contact connecting the route circult to a source of current when the signal lever for the correspondin signal is normal and

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