US2095703A - Centralized traffic controlling system for railroads - Google Patents

Description

Oct.l12, 1937. T. J. JUDGE l CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed NOV. 7, 1934 5 Sheecs-SheekI ll NTR TToRNY Wg. A T 2 N E lj M V w m /W E HI mm M uo @L E@ +V mvv -i 3 VS I3 L Nv nm; L: @LJ Q 2 mm f /MH ziiii l 95 Smuz Nm Wma Oct. 12, 1937. T JUDGE 2,095,703

CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAI-LROADS Filed Nov. '7. 1934 5 Sheets-Sheet 2 "P V p v :r P. fr Y l1 [L D f ,'1 r-l T. J. JUDGE Oct. 12, 1937.

" CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILHOADS 5 Sheets-Sheet 3 T. J. JUDGE CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS 5 Sheets-Sheet 4 INVENTO ATTORNEY Filed Nov. "i,y 1934 maa T J. JUDGE CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed Nov. 7, 1934 5 Sheets-Sheetl 5 Patented ct. 12, 1937 v UNITED sTATEs CENTRALIZED TRAFFIC CONTROLLING SYSTEMiFOR RAILROADS Thomas J. Judge, Rochester, N. Y., assignor to General Railway. Signal Company, Rochester,

N. Y. Y

Application November 7, 1934, Serial No. '751,828

8 Claims.

This invention relates to centralized traflic controlling systems for railroads and it more particularly pertains to the communication part'of such systems. Y

In railroad traino controlling systems as contemplated by this invention the traic at an outlying field station is controlled from a control office. The present invention contemplates `a system in which the switches and signals at Va single station located along a railroad system are placed under the supervision of an operator at the control oilice. The condition of ithe switches, signals and various other traffic controlling devices at the location are'transmitted to the control oflice for providing the operator With the information necessary for governing train movements. In a system of this type the switches and signals are associated with such automatic block signalling means as may be necessary underv the particular conditions met in practice, in order that the manual control bythe operator may be effected in a safe and reliable manner. Y

It citen happens that there are several outlying z track switches with their associated signals located adjacent or near eachother with the traffic governing devices preferably governed from a central tower of an interlocking plant or other established cnice. Ordinarily such control would be effected over the usual direct line Wire type of system but the present invention providesl a selector type system particularly adapted to an installation of this type.

In accordance with the present invention the communication system comprises three line wires extending from the control oice to the outlying Y field station. These three line Wires are referred to in this disclosure as j the control line CL, the indication line IL and the common line CM. Line CLT, in addition to beingused for transmitting the controls from the oflicetothe eld station, is used rto control the synchronous step-b-y-step operation of the steppingl relay( banks at both ends of the system. Line IL is r used for transmitting indications fromthe eld station to the control oice and line CM is the common return conductor for both theA control and indication lines. Y

In this system either control impulsesffare transmitted from the control office or indication impulses are transmitted from `the field station during any particular operating cycle. The con'' trol impulses are made distinctive by reason of their polarity for the purpose of transmitting the desired controls.` The indication impulses A,are made distinctive by energizing or not energizing the indication line at a particular step of a cycle for the purpose of transmitting the desired indications.

` l To accomplishr'the above the system of the present invention provides a line battery or other suitable source at the control oice, with the circuits so arranged that irrespective of the location which is transmitting, the controls or the indications will be transmitted by energizing the 'control or indication line circuits with current 'from asing'le source of current located in the control oiiice. This is an important feature of the present invention since it has been customary to provide separate line batteries for the purpose of transmitting controls and indications over separate circuits between locations.

Since the system is of the coded duplex type it is operated through cycles during each of which transmission of controls and/or the transmission of indications may occur. When controls are transmitted a predetermined number of impulses are applied to the control line circuit for operating'the step-by-step mechanisms at both locations 'through a cycle in synchronism. These impulses areV of selected polarities for operating the apparatus at the eld station. In other Words,l the distinctive character (polarity) of the impulses determines the particular controls to be transmitted to the station.

i `For the transmission of indications a predetermined number of impulses are applied to the control line at the control oflice for operating the stepping mechanisms through a cycle of operations. During this cycle the distinctive condition (energized or deenergized) of the indication line determines the. particular indications to be transmitted to the control oliice.

impulsing, for the'transmission of controls and r for the transmission of indications.

`These characteristic features of the present invention thus briey stated Will be explained more inl detail in'the following description of one embodiment of the invention. Various other characteristic features, jfunctions and advantages of a system embodying this invention will be in part pointed cut and in part apparent as the description progresses.

Figs. 1A and 1B illustrate the apparatus and circuit arrangements provided for a typical control oH-ice arranged according to the present invention.

Fig. 2 illustrates the apparatus and circuit arrangements employed at a typical eld station for receiving controls and for transmitting indications to and from the eld station in accordance with the present invention and adaptedtobe associated with the apparatus employed in the control oiiice.

Figs. 3 and 3B show a modification of theindication registering circuits in the control oice.

Although the present invention has been shown applied to the control of a singleswitch and its associated signals such as used at one end of a passing siding, it should be understood that the invention is not iimited as thus shown but may be extended for any number of desired switches and signals and may readily-be applied to all types of track layouts. Y.

In the event that a larger number of switches and signals are located at the field station the system may be extended in any one of several ways. For example, a greater number of steps may be employed to merely duplicate the apparatus illustrated. Or the controls and indications may be divided into several groups, any

yone group of which could hold communication with the oiiice during anyone particularl operating cycle as disclosed for example in the pending application of XV. D. Hailes etal., Ser.V No. 526,674, ledMarch 3l, 193i. It is understood that all such auxiliary features and modifications may be applied to the present invention without in any way limiting or detracting from the scope of the invention. Y

For the purpose of simplifying the illustrations and facilitating in'the explanation, the

Yvarious parts and circuits have been diagrammatically shown with certain conventional illustrations employed. The drawings have been made more for the purposeof making it easier to understand the principles and method of operation rather than with the idea of illustrating the specific consideration and arrangement of parts that would be employed in practice. For example, the various relays and their contacts are illustrated in a conventional manner and symbols are used to indicate connections to the terminals of batteries or other sources of current instead of showingV all the Wiring connections to these terminals` The symbols (-l-) and are employed to indicate the positive and negative terminals respectively of suitable sources of direct current and the circuits with which these symbols are used always have current flowing in the same direction. The symbols (B+) and (B-) indicate connections to the opposite terminals of Va suitable battery or other direct current source which has a central or intermediate tap (CN) and the circuits with which these symbols areA used may have current flowing in one direction or the other depending upon the particular terminal use d in combination with the central or intermediate tap (CN).

Control apice equipment-#The control ofce (Figs. 1A and iB) includes, fbesides the above mentioned apparatus, aquick acting line relay F of the neutral type which repeats each energization of the control line circuit irrespective of the polarity of such energization. A quick acting line repeating relay lFP repeats each energization of line relay F and a quick acting line repeating relay ZFP repeats each actuation of relay lFP.

A slow acting line repeating relay SA of the neutral type is provided with such slow acting characteristics that it does not drop away between the successive energizations of the line repeating relay ZFP. Relay SA is energized at the be- -ginning of a cycle and remains energized until a predetermined time at the end of a cycle. A similar slow acting repeating relay SB repeats the actuation of relay SA and relay SB likewise is picked up at the beginning of a cycle, remains energized throughout the cycle and is dropped after a predetermined interval of time at the j end of a cycle.

Positive code sending relay PC and negative code sending relay NC are for the purpose of energizing the. control line with positive and negative impulses respectively in accordance with the characteristic code to be transmitted from the control office to the station. Cycle controlling relay OC is picked up at the beginning of either a control cycle or an indication cycle and remains up throughout the succeeding steps of the cycle.

An impulse controlling relay Eis jointly controlled by the stepping relays at the Various steps of a cycle for applying impulses to the control line circuit by means of the operation of the PC and NC relays.

Associated with the line repeating relays is a bank of stepping relays including relays IV, 2V and 3V together with an associated half-step repeating relay VP. This bank of relays is for the purpose of marking off the successive steps of each cycle.

Message receiving relays MB and MF are provided to receive the condition of the indication line circuit during the transmission of indications. The conditions of relays MB and MF at the various steps of the cycle are stored during the different periods by suitable indication storing relays such as RK, NK AND TK. Relay MB also serves as a start relay for both control and indication cycles.

The controlling apparatus for the track switch and signals at the illustrated eld station comprises a switch machine control lever SML, a signal control lever SGL and a starting button STB. A miniature track switch would ordinarily be provided but in order to simplify the present disclosure this portion of the apparatus has been omitted. Track occupancy lamp TI has been illustrated to indicate how the condition of the illustrated track is indicated in the control ofce. Likewise switch lamp W is provided to indicate correspondence and lack of correspondence between the switch machine lever and the track switch at the field station.

Field station equipment-The eld station (Fig. 2) includes, besides the above mentioned apparatus, a quick acting line repeating relay F1 of the polar type which repeats the impulses applied to the control line circuit. Repeating relay FP1 repeats each actuation of relay F1 irrespective of the polarity of the impulse which actuates relay F1. Slow acting relay SA1 is for a purpose similar to that explained in connection with relay SA in the control oice.

The eld station includes a stepping relay bank comprising stepping relays lV1, ZV1, 3V1 and half-step relay VP1 operating in synchronism Cil :relay WP of the polar neutraltype. Relay WP is controlled by a suitable polarized circuit (not shown) so that the relay is energized with current of one polarity or the other depending upon the normal or reverse position of Y the track switch and it is deenergized whenever the track switch is unlocked or in operation.

The signals lA-IB are provided for governing traic over the main track and over the turn-out track respectively in an east bound direction. The signals ZA--ZB are provided for governing traflic over the main track or over the turn-out track respectively in a west bound direction.

Since the detailed circuits for controlling the switch machine and the signalsY are immaterial to an understanding of the present invention, this control is only indicated by dotted line connections to the control relays. Switch control relay WZ is`for the purpose of controlling the op.- eration of the track switch to its normal and its reverse positions. vSignal control relays RD and LD are for controlling signals for directing traic in a right and a left direction respectively. These control relays are governed from the control office in accordance with selected code combinations. For the purpose of illustrating the manner in which the system is initiated from the field station, a change relay CH has been indicated as being in its normally picked up condition.y

It is believed that the nature of the invention, its advantages and characteristics features can best be understood with further description being set forth from the standpoint of operation.

Operation The general plan of operation of the system contemplated by the present invention may be understood by placing Fig. 2 to the right of Fig. 1A and Fig. 1B below Fig. 1A with correspondingly numbered and lettered lines in alinement. These two drawings illustrate a system having a control oice and a fieldstation. A control line wire CL extends from the control ofce to the eld station and at the eld station isconnected to common return wire CM. Similarly, an indication line wire IL extends from the control ofce to the field station and is arranged to be selectively connected to the common return'wire in Various combinations under Various operating conditions. v

The control line circuit includes a neutral line relay F inthe control office and a polarized line relay F1 at the field station. Eenergy for the control line circuit is supplied from a line battery LB in the control office with the particular polarity for energizing the control line circuit selected by pole changing contacts located on code sending relays PC and NC. When the code sending relay PC is energized a positive impulse is applied to the control line circuit and when code sending relay NC is energized a negative impulse is applied to the control linecircuit. With both code sending relays energized or deenergized the control line circuitis maintained deenergized. Whenever energy is Yapplied to the control line circuit by the code sending relays, the energization of the line is broken up into time spaced impulses by the intermittent operation of Y relay E, which deenergizes the particular code sending relay which is picked up at that time.

The indication line.` circuit includes message relays in its two branches in the control oce and it includes impulsing contacts inthe corresponding branches at the eld station. Since corresponding lbranches are selected at the control ofce and at the field station when the control line circuit is energized (front contacts on the line repeating relays closed) and since corresponding branches are connected in series during the deenergized condition of the control line circuit (back contacts closed onthe line repeatingrelays), these two branches of the indication line circuit at the control oiice and at the eld station are conveniently termed front and back branches. In the oflice a message relay MB is included in the back branch and a message relay MF is included in the front branch. At the field station the front and back branches arev respectively conditio-ned when the line repeating relay is picked up and dropped away in accordance with the indications to be transmitted. The indication line circuit is supplied with energy from the same line battery LB in the control oilice that applies energy to the control line circuit.

Both line circuits are normally deenergizedfor the purpose of rendering the system capable of indication line wire to the common wire which picks up relay MB. At the control oflice the system is initiated by picking up relayMB over a local circuit.

It will be observed from the description which follows that indications will be transmitted from the ield station to the control oice during the same cycle that controls are transmitted from the office to the station.V Thereld station initiating circuit is so arranged that the change relay which initiates the system from the eld station will be resensitized at the beginning of a cycle. The effect of this feature is to cause the system to step through a succeeding cycle if during the previous cycle a change has taken place requiring the transmission of indications. In other words, a change in conditions may take place during a cycle after the point associated with this condition on the stepping bank has been passed. In this event, since the change relay is is energized when the track section is unoccupied. Switch repeating relay WP is energized when the switch is in either of its extreme locked positions, with its polar Contact positioned'to the left with the switch in its normal position and to the right with the switch in its reverse position.

Direction relays RD and LD and switch machine control relay WZ areof the magnetic stick typeland although their windings .are normally deenergized the `polar contacts remain in the positions to which they were last actuated. Change relay CH is normally energized over a stick circuit extending from (-1-), front contact |00 of relay T, front contact lill -of relay WP, front contact vM122 and lower winding of relay CH, to

Manual .starting-With the system in its normal condition the operator can initiate the system for the transmission of such controls as he may desire. For example, if it is desired to operate track switch TS or to govern signals iA-lB and 2A-2B the control levers SML and SGL in the office are properly positioned, after which starting button STB is actuated.

It will be noted that the operator may move the control levers to different positions without transmitting controls until such time that button -STB is actuated. Such an arrangement is to be considered as merely one embodiment of the present invention since the system might readily bearranged to be initiated upon the actuation of one or more of the control levers in the manner shown, for example, inthe Preston application, Ser. No. 573,079, led November 5, 1931, corresponding to British Pat. No. 406,418 and French Pat. No. 745,343.

The actuation of starting button STB with the system at rest causes the energization of relay MB :over a circuit extending from (-1-), contact l0 of button STB, back contact ll of relay SA and upper winding of relay MB, to Relay MB closes a stick circuit for itself extending from (-1-), back contact l2 of relay SB, back contact' 13 of relay E, front contact lf3 and upper winding of relay MB, to The operation of relay MB closes a circuit for picking Vup relay OC which extends from (-1-), front contact l5 of relay MB, back contact I6 oi relay SB and winding of relay OC, to

The `operation of relay OC closes a circuit for picking up relay PC which extends from (-1-), front contact Il of relay MB, front contact I8 of relay OC, back contact I9 of relay E, back contacts 2li, 2l and 22 of relays 3V, 2V and lV respectively, contact '23 of lever SML in its left hand position, PC bus and winding Vof relay PC, to This applies an initial positive impulse to the control line over a circuit extending from the (-1-) terminal of battery LB, front contact 24 of relay PC, back contact 25 of relay NC, winding of relay F, line conductor CL, winding of relay F1, common conductor CM and back contact 2S of relay NC to the terminal of battery LB.

This energization of the'control line circuit energizes relays F and F1 and since the impulse is positive, relay F1 positions its polar contacts to the right. Relay F closes a circuit for picking up relay iFP which extends from (-1-), front contact 2 of relay F and winding of relay iFP, to Relay EFP closes a circuit for picking up relay EFP which extends from (-1-), front contact 28 of relay IFP and winding of relay 2FP, to The operation of relay F also closes a pick up circuit for relay SA extending from (-1-), front contact 29 of relay F and Winding of relay SA to Relay SA closes a pick up circuit for relay SB extending from (-1-), front contact 3E) of relay SA and winding'of relay SB, to

At the iield station the operation of relay F1 closes a circuit for picking up relay FP1 which extends from (-1-) contact 93 of relay F1 in its right hand dotted position and Winding oi relay FP1, to Relay FP1 closes a circuit for picking up relay SA1 which extends from (-1-) front contact |134 of relay FP1, and winding of relay SA1, to

Referring to the control office the picking up or front Contact 3| of relay SA before the opening of back contact I2 of relay SB maintains energy on the stick circuit of relay MB. The picking up of back contact Il of relay SA opens the circuit leading to button STB so that any further operation of this button is ineffective to control relay MB.

Polarity selection of stepping impuZses.-When Athe system is initiated by the energization of relay OC, above explained, the impulses placed upon the line circuit for the succeeding cycle of operations are of polarities determined by the positions of the switch machine and signal levers, which levers select the code determining relays. As above mentioned with lever SML in its normal position relay PC is picked up to apply a 4(-1-) impulse to the line circuit. If lever SML is in its Vreverse position then the above traced circuit through back contact 22 of relay lV extends through contact 23 of lever SML in its reverse position and the NC bus to4 relay NC. The picking up of relay NC causes a impulse to be 1 applied to the controlline over a circuit extending from the terminal of battery LB, back contact 32 o1" relay PC, front contact 25 of relay NC, winding of relay F, conductor CL, winding of relay F1, conductor CM, front contact 26 of relay f NC and back contact Ell of relay PC to the (-1-) terminal of battery LB.

This energization of the control line circuit is repeated by relays F and F1, but with a impulse applied to this line circuit relay F1 actu- 1% ates its polar contacts to the left. Contact H13 ci relay F1 is effective to pick up relay FP1 in both its right or it hand positions.

It lwill now be assumed that the application of the first impulse to the control line circuit results in the picking up of relay VP in the oiiice and relay VP1 at the station, The picking up of relay VP at the cnice eiects the picking up of relay E, as will be later described, to deenergize the control line circuit and the deenergization of this f ,line circuit causes relay IV to be picked up. Contact 22 of relay i V then extends thegcircuit from (-1-) front contact 33 of relay SA to Contact 3 of the signal lever.

With the signal lever in its stop position as f shown this circuit is extended through the NC busand the Winding of relay NC, to thus applying a impulse to the control line on the second step. It will be apparent that if signal lever SGL is in its right hand position, contact 1 il :causes relay NC to be picked up so that this .impulse is likewise yci polarity. With lever SGL in its left hand position the above described circuit is extended by way of the PC bus to relay PC for making the impulse positive in character.

When relay 2V is picked up following the second impulse, contact 2! shifts the circuit to contact 3% of lever and with this lever in its stop or left position, relay NC is energized to apply a impulse to the line on the next step. With contact 3&3 in its right hand position then relay PC is picked up to apply a (-1-) impulse to the control line on this step.

I mpalsing the Zine- As above mentioned it will be assumed that relay VP is picked up on the rst impulse applied to the control line circuit. This closes a circuit for picking up relay E which extends irom (-1-), front contact l2 of relay SB, back contacts 36, 37 and 38 of relays 3V, 2V and lV respectively'front contact 39 of relay VP and.`

winding of relay E, to The picking up of relay E opens (at back contact I9) the circuit of the particular code sending relay which was selected. The dropping of the code sending relay (relay PC in the assumed example) deenergizes the control line circuit at contact 24 of relay PC. In the event that relay NC is picked up then the dropping of contacts 25 and 26 ofthis-relay deenergizes the control line circuit.' i'

The deenergization of repeated by the dropping of relays F, IFP andZFP in sequence. This eiects the picking up of relay IV, which in turn deenergizesV relay E bythe picking up of back contact 38 of relay IV.- Relay E drops and when the next selected code sendi ing relay is picked up the control line is again energized, resulting in relays F, IFP and-2FP being picked up in sequence.

The picking up of relay 2FP causes relay-VP to drop which closes a pick up circuit for relay E extending from (-1-) front contact I2 of relay SB, back contacts 36 and 3'! of relays 3V and VV respectively, front contact 38 of relay IV, back contact 39 of relay VP and winding of relay E, to The picking up of relay E drops the code sending relay as before which deenergize's the control line circuit for dropping relays F, IFP and 2FP in sequence. The dropping of relay 2FP picks up relay 2V which opens the circuit of relay E at back contact 3l. the selected code sending relay is picked up for again energizing the control line circuit.

Relays F, IFP and 2FP are now picked up in sequence and the picking up of relay 2FP causes relay VP to be picked up which closes a circuit for picking up relay E extending from front contact i2 of relay SB, back contact 36 of relay' 3V, front contact 31 of relay 2V, front'contact 39 of relay VP, andwinding of relay E, to

The picking up of relay E drops the selecting code sending relay which deenergizes the line circuit for dropping relays F, IFP and 2FP in sequence. The dropping ofv relay 2FP picks upv relay 3V which 'deenergizes relay Eat back con-'i `tact 36.

The dropping oirelay'E closes the'circu'it Vfor picking up the selected code sending relay, {after which the line is again energized for picking up relays F, IFP and 2FP in sequence.

closes a circuit for picking up relay E extending from front contact i2 of'relay SB, front contact 36 of relay 3V, back contact 39 of relay VP and winding of relay E, to V i The piek-ing up of `'relay Edeene'rgies the selected code sending relay-which drops to de'energize the line for dropping relays F, IFP'and 2FP in sequence. A

Since therev are no additional stepping relaysv in the present embodiment, relay E remains energized resulting in the deenergization of the con'- A normal. Y

stepping relays so that theyare-all restored to i Relay MB, which was picked up to initiate the cycle, is dropped during the rst deenergized period oi the line circuit by the dropping of contact 40 of relay 2FP. The picking up of relay IE to mark the beginning of the firstdeenergized'- the control line `is- Relay E drops and The picking V "up of relay 2FP dropsy relay VP which in turn or off periodof the line circuit opened the stick stick `circuit `was maintain-ed energized at front contact' 40'of relayv 2FP.: Howeven'during the rst o period relay E being up with its Vback contact I3 open when relay 2FP is dropped to open front Contact A0, the stick circuit of relay MB is deenergized and this relay is released.

Relay OC is maintained energized throughout the cycle over a circuit extending from (-I-), front contact'lll of relay Eyfront contact 42 'of relay OC, front contact I6 of' relay SB and winding of relay OC to( At the end of the cycle the dropping of relay SB opens (at its front contact I6) the circuit of relay OC and this relay is deenergized. v

Stepping relay ba11.l ;.-Thedetailedl circuits of the steppingrelays in the control oiceand at the eld station have not been shown since these relays may be operated at the various steps of the cycle in any well known manner. Those atthe office and at the eld, station operate in synchrov nism and thev detailed fcircuits may be such as shown in the Pat. No.'2',058,824 dated October 27, 1936, granted to* W. T. Powells In this prior patent the stepping line is normally deenergized and the VP relay is picked up on the first energized period,'dropped on the second energized period, picked up on `the third energized period, dropped on the fourth energiz'edrperiod, etc., with the stepping relays being `picked up in rotation during the succ'eedingdeenergized periods.' The present embodiment contemplates a similar operation of the stepping relay bank and in order to keepl the drawingsas simple as possible the control of the `stepping relay'banks liasbeen merely indicated by? dotted line connections extending from the FP andslow acting relays to the stepping relays.

Transmission of comf1'oZ. .-WithV the switch machine and the signal control levers in the positions shown in Fig. 1A the control line circuit is energized with a combination of impulses cornprising This is because contact 23 of Ylever SML Vselects relay PC for making Y the rst impulse and contacts 34 and 35 of leverSGL select relay NC for making the second and third impulses while front contact 20 of relay' 3V connects Vdirectly to relay NCor making the fourth impulse It will be understood in this connection that front contact 20 may selectively connect to relays PC and NC through-contacts of other controlling devices for providing a selection of impulses on this step if desired.

The first impulse positions relay Fl tothe right whichlcloses a circuit for energizing relay WZ extending from contact lil of relay F1 in its right'hand dotted position, back contacts |06, |01 and,l |08 of relays 3V1, 2V1 and lVl respectively and upper winding of relay WZ, to This polarity of energization actuates contact |09 of relay WZ to the right Yfor causing switch machine SM to actuate the track switch to its normal position.

In the event that the rst impulse is then relay WZ is energized through its lower winding for reversing the position of contact IUS, over a circuit extending through contact |05 of relay F1 in'its left hand dotted position, back contacts H0, III and II2 of relays 3V1, 2V1 and lVl respectively and lower winding of relay WZ, to Relay WZ in this position causes the track switch to be actuated to its reverse position.

f the cycle in the same manner previously kmen-- The second impulse being actuates relay F1 to the left for closing a circuit through the lower winding of relay LD which extends from contact i535 of relay F1 in its left hand dotted position,.back contacts IIE) and III of relays 3V1 and Vl respectively, front contact II2 of relay IV1, and lower winding of relay LD, to l The third impulse being relay F1 is again actuated to the left which closes a circuit through front contact III of relay 2V1` Yand the lower winding of relay RD, to v With relays LD and RD actuated to the left nol signals are cleared which repeats the position of the signal control lever in the control o-iiice, that is, all signals at stop;

From the above description of the operation of relay WZ it will be readily apparent that relays LD` and RD may be selectively actuated to the right for clearing their associated signals in response to the right hand or left hand positions of lever SGL in the control oiice. It will also be apparent that the use of the` fourth impulse for selectively actuating the line circuit would mean that front contacts I andV IID of relay 3V1 wouldbe connected to a control relay to be selectively actuated by this impulse.

Automatic start-A change. in theI indication conditions at theV eldstation may include a change in the condition of the detectortrack section, a change in the condition of the trackY switch or any one of several other devices, but

which circuit extends from the (+V). terminal of battery LB, lower Winding of relay MB, back contacts 43 and i4 of relays PC and NC, back contacts V45 and d5 of relays IFP and 2F13, line Yconductor IL, backcontact H3'of relay FP1, back contact IIfi of relay VP1, back contacts IH. and II5 of relays 3V1 and IV1, back contact H8 oi rrelay SA1, back contact IIS of relay CH, conductor CM and back contact 26 of relay NC to 'initiates the system into acycle of operations,

as before, and the stepping'relay banks inthe.`

control oice and at the ieldv station step through tioned. Y

During this cycle, controls are transmitted in accordance with the position of the control levers and indications are transmitted in accord- Thus relay CH is madev is actuated to its reverse position during a control cycle in response to the actuation of lever SML to its reverse position. The change-over of contact IIJI of relay WP from its front to its back point, during the time that relay WP is deenergized when the switch machine is in operation, drops relay CH for initiating the cycle as above described. c

Relay WP actuates its polar contact 22 to 'the right when the track switch is in its reverse locked position. The stepping relay banks in the cnice and at the station are stepped through a cycle of operations as previously described.

The indication that the switch is in its unlocked position is transmitted due to front contact i513 of relay WP being open. With this contact open the indication line conductor IL is not energized during the first two impulses of the cycle because of the open contact 23,

With conductory IL deenergized, relay MB will not-be picked up (after it is dropped during the iirst 01T period as previously described) so that an executing circuit is closed for actuating relay RK to the left which extends from (B-), back contact 47 of relay MB, front contact 58 of relay IFP, back contacts i9 and 50 of relays 3V and 2V respectively, front contact 5I of relay lV and winding of relay RK, to (CN). This is conveniently referred to as an on indication since the control line is` energized for picking up relay IFP and closin-g its front contact 58.

Relay MF is likewise not energized so that an 01T indication is executed which actuates relay NK to the left when relay IFP is deenergized. 'This circuit extends from (B back contact 52 of relay MF, back contact 53 of relay IFP, front contact 54 of relay SA, front contact 55 of relay VP, back contact 55 of relay 2V and winding of relay NK, to (CN).

With the contacts of relays RK and NK in their left hand positions a circuit is closed for lighting lamp W extending from contact 5'I ofy relay RK in its left hand position, contact 58 of relay NK in its left hand dotted position and lamp W, to This is an indication to the operator that the switch at the station is in its unlocked condition.

When. the switch reaches its reverse locked position, relay WP is energized so that the switching of its contact EBI from a back to a front point again deenergizes relay CH' to initiate another cycle of operations.

Before describing the transmission of indications for this cycle'it will be pointed out that lamepW is lighted when lever SML is actuated to its reverse position, out of correspondence with the position of the switch at the station as repeated by relays RK and NK. Relay RK has its contact 5'I actuated to the left as an indication that the switch is in its normal position and relay NK has its contact 58 actuated to the right as an indication that the switch is in its normal position. When contact 59 of lever SML is actuated to its right hand dotted position a circuit is closed for lighting lamp W which extends from Contact 51 of relay RK in its left hand position, contact 5B of relay NK in its right hand position, contact 59 of lever SML in its right hand dotted position and the lamp W, to The lighting of this lamp is an indication to the operator' that the switch at the remote station is not in correspondence with the lever in the oilice.

When the switch reaches its reverse position, relay WP repeats this condition by actuating its polar contact |22 to its right hand dotted position. Relay MB in the oiice is not deenergized during the first off period under this condition when relay 2FP opens the stick circuit of relay MB at front contact li. This is because an energizing circuit is completed through the lowe:

winding of relay MBover the indication line. This circuit extends fromthe (1) terminal of battery LB, lower` winding of relay MB, back contacts 43 and of relays PC and NC respectively, back contacts t5 and 4E of relays IFP and 2FP respectively, line conductor IL, back contact I I2 of relay FP1, front contact I I4 of relay VP1, back contact II of relay 2V1, contact |22 of relay WP in its right hand dotted position, front contact |23 of relay WP, conductor CM and back contact 26 of relay NC to the terminal of battery LB.

Relay MB is thus maintained energized by way of its lower winding until relay E drops to close the stick circuit for'relayv MB at back contact I3. This condition is executed for actuating relay RK to' its reversefposition when relay iFP picks up, over a circuit extending from (B+),

front contact lll of relay MB, front contact 48 of relay EFP, back contacts i9 and 5) of relays 3V and 2V respectively, front contact 5I of relay I V and winding of relay RK, to (CN).

Since lever contact 59 is to the right there is no' energy applied to lamp W through contact El in its right hand dotted position, so that this lamp is extinguished as an indication that cor respondence exists between lever SML and the track switch.

There is no circuit closed under this condition for actuating relay MF and when this indication is executed by the droppingof relay IFP, a cir-v cuit is closed for actuating relay NK toI the left (reverse) extending from (B back contact 52 of relay MF, back contact 53 of relay EFP, front Contact 54 of relay SA, front contact 55 of relay VP, back contact 5t of relay 2V and winding of relay NK, to (CN). This positions contact 58 of relay NK to the left which is ineiective to control signal lamp W because contact 5l of relay RK positioned to the right.

Since it is assumed that track relay T is energized, the indication line is not energized when the next step is taken because of open contact I 25?, of relay T. This results in relay MF being deenergized during the next step so that relay TK is conditioned for actuating its polar contact to the left over a circuit extending from (B back contacts 52 and 53 of relays MF and IFP respectively, front contact 5ft of relay SA, back Contact 55 of relay VP, back contact of relay 3V, front contact 6I of relay IV and winding of relay TK to (CN).

In the event that relay T is `deenergized during this step, then relay MF would be picked up over a circuit through the lower winding of relay MF selected in accordance with the particular code sending relay VPC or NC which is energized. If relay PC is energized then the circuit for energizing the circuit including the lower winding of relay MF extends from the terminal of battery LB, front contact 62 of relay PC, lower winding of relay MF, front contact S3 of relay PC, back contact 54 of relay NC, iront contact 65 of relay IFP, front contact t@ of relay ZFP, conductor IL, frontcontact II3 of relay FP1, back contacts IE5 and |26 oi relays @V1 and 2V1 respectively, front contact E21 of relay IV1, back contact |24 of relay T, conductor CM and back contact 26 of relay NC to the terminal of battery LB.

In the event that relay NC is picked up in-A stead of relay PC, then a circuit is eiective now traced from the terminal of battery LB, front contact d of relay NC, back contact 63 of relay PC, lower winding of relay MF, back contact G2 of relay PC,` front contact 64 of relay NC, front contact 65 of relay IFP, front contact t@ of relay 2FP, conductor IL, front contact IIS Vof relay FP1, back contacts |25 and |26 of relays tti of relays PC and NC are4 for the purpose ofV energizing the pickup (lower) winding of relay always in the same direction so that it will be maintained energized when its stick circuit is completed.

When relay MF is picked up it is stuck up over a circuit extending from front contact 3i of relay SA, front contact ISof relay E, front contact Iii and upper winding of relay MF, to Nhen relay ZFP drops it energizes this stickcircuit at back contact it so that relay MF is not dropped when relay E' opens its front contact i3.

This condition is executed when relay IV is picked up and since it is assumed that the track section is occupied, the picking up and sticking oi relay MF closes a circuit for actuating relay to the right extending from (B+) front contact 52 of relay MF, back contact53 of relay IFP, front contact 5 of relay SA, back contact 55 of relay lfback Contact @il of relay 3Vront contact ifof reiay iV and winding of relay TK to (CN). The actuation of contact t8 of relay TK to the right closes an obvious circuit for lighting lamp TI to indicate to the operator that the track section is occupied.

After this indication has been executed relay is dropped when relay 2F? picks up its contact di?, since at this time relay E is down so that front contact I3 is open and'back Contact 4E! is open to deenergize the stick circuit of relay MF.

Relays MB and MF may thus be conditioned at other steps of the cycle ina similar manner for transmitting other indications from the iield station to the control office.V

When the system has taken the last step the line circuit is maintained deenergized for a suincient period of time to drop the slow acting relaysin the same manner previously described in connection with a control cycle. It is to be understood that, although lamps have been selected for advising the operator of the conditions at the iieldstation, other suitable indicator means such as audible signals, miniature movabletrack switch pointsor the like, may be employed as desired.

Modification-The modiiication shown in Figs.

Y 3A and 3B contemplates the use of a single message relay M in place ci the two message relays lVIB and MF of Figs. .lA and 1B. The reference characters in 3A and 3B are the saine for those devices which correspond to the devices of Figs. 1A and 1B, and only those relays and contacts which` are characteristic of this modication have been given distinctive reference characters. Itis also to be understood that this modiii. tion, cr control cnice arrangement, is to be .-loyed with theiield station apparatus disclosed in 2 in a similar manner as described in connection with Figs. lA and 1B.

Relay M is pickedup to initiate a cycle from th-e eld station when energy is applied to conductor IL in the same manner as described in connection with Fig. 2. Current flows from the terminal of battery LB, through back conv tact 26 of relay NC, over conductor CM, through back contacts H3, H8, H5, Ill, H4 and H3 of relays CII, SA1, iVl, 3V1, VP1 and FP1 respectively, conductor IL, through back contacts 200 and Zei of relays 2FP and F respectively, upper winding oi relay M and back contact 202 of relay NC to the (-l) terminal of battery LB. Relay M is stuck up over a circuit extending from the (-1-) terminal of battery LB, back contact 22 of relay NC, upperY winding of relay M, front contact 205i of relay M, back contact 2&33 of relay SB and resistanceRS, to the terminal of battery LB. This stick circuit maintains relay M energized until the picking up of relay SB, after which it is dropped ready for the rst indication circuit.

During succeeding steps of the cycle the indication line conductor IL is conditioned during the onperiods at the eld station by energizing or deenergizing this conductor. If it is energized with relay PC picked up, relay M is picked up over a circuit extending from the (-1-) terminal of Abattery LB, back contact 202 of relay NC, upper winding of relay M, iront contacts 2m and 200 of relays F and ZFP respectively, conductor ,'IL, front contact H3 of relay FP1, through the channel selecting contacts-of the stepping relays, through the contact of the relay which connects conductor IL to conductor CM (such as back contact E26 of relay T) and over conductor CM to the terminal of battery LB by way of back contact 26 of relay NC.

If relay NC is picked up at this particular step, then the circuit extends from the terminal i battery LB, back contact 24 of relay PC (see Fig. 1A) front Contact 26 of relay NC, conductor CM and through the selecting contacts at the iield station, through front contact H3 of relay FP1, conductor IL, front contacts 200 and 20E of relays 2FP and F respectively, lower winding oi relay M and front contact 205 of relay NC to the terminal of battery LB. In the event that conductor IL is not energized at this particular step relay M will remain deenergized. This provides a choice of two on indication conditions which are executed when relay E picks up and closes its front contact 20'!! and before relay F is dropped to open its front contact 208.

The choice of two off indications is provided by energizing or not energizing conductor IL during the o periods when the line and line repeating relays are deenergized. For example, if conductor IL is -energized during a particular ofi periodV the circuit for energizing relay M extends through back contacts 20d and 20! of relays EFP and F respectively and through the upper winding of relay M to the V(-|-) terminal of battery LB by way of back contact 202 or" relay NC. It will be obvious that since this is an off period, relays NC and PC will be deenergized so that the terminal of battery LB is connected to one terminal of the upper winding of relay M through back contact 202 of relay NC. The terminal of battery LB is connected to the other terminal of the upper winding of relay M through back contact 26 of relay NC, by way of conductor CM to the station, conductor IL back to the office and over back contacts 200 and 20l of relays FP and F. In the event that conductor IL is deenergized during a particular off period then of course relay M remains down. This gives a choice of two oi indications which are executed by way of back contact 208 of relay F and back contact 2%5 of relay E -just before the start of the next succeeding on period.

It is to be understood that the modication of igs. 3A and 3B may or may not be used in place of Figs. 1A and 1B and that only a single line battery is used in either case. Although the times during which the indication conditions are executed by energizing the indication channel circuits may not be as long when the modification of Figs. 3A and 3B is used, it will be apparent that suilcient time is obtained to operate a fast acting magnetic stick type relay and that a saving in apparatus is realized.

Having thus described a centralized trafc controlling system as one specic embodiment of the present invention it is desired to be understood that the form is selected to facilitate in the disclosure of the invention rather than to limit the number oi forms which it may assume. It is further to be understood that various modifications, adaptations and alterations may be applied to the specic form shown to meet the requirements of practice without in any manner departting from the spirit or scope of the present invention except as limited by the appended claims.

What I claim is:-

1. In a remote control system, a plurality of locations including a control ofce and a eld station, means for synchronously marking oi a series of successive time spaced impulseperiods at said locations, an indication line circuit connecting said locations, an impulse repeating relay, a message receiving relay, means causing said indication line circuit to be impulsed by said impulse repeating relay during impulse periods and means causing said indication line circuit to be impulsed by said impulse repeating relay during time space periods whereby messages are transmitted over said indication line circuit, means inserting said message receiving relay in said indication line circuit during said impulse periods, means inserting said message receiving relay in said indication line circuit during said time space l periods, and means controlled by said message receiving relay for registering messages transmitted by the impulsing of said indication line circuit.

2. In a remote control system, a plurality oi locations including a control oiiice and a field station, a source of current at one of said locations,means for synchronously marking oi a series of successive time spaced impulse periods at said locations, an indication line circuit connecting said locations, an impulse repeating relay, a message receiving relay, means including said source of current for causing said indication line circuit to be impulsed by said impulse repeating relay during impulse periods and means including said source of current for causing said indication line circuit to be impulsed by said impulse repeating relay during time space periods whereby messages are transmitted over said indication line circuit, means inserting said message receiving relay in said indication line circuit during Said impulse periods, means inserting said message receiving relay in said indication line circuit during said time space periods, and means controlled Y by said message receiving relay for registering messages transmitted by the impulsing of said indication line circuit.

3. In a remote control system; a plurality of locations including a control oiceand a eld station; a stepping line circuit and an indication line circuit connecting the control office and the 'trol oiice; impulsing means at saidicontrol oice for marking off a series of positive and negative time spaced impulses on said stepping circuit, said stepping circuit receiving energy for such impulses from said sourcerof current; an impulse repeating relay; step-,by-step means at the field station operated one step at a time in response to said series of impulses on said stepping circuit as repeated by said impulse repeating relay; means governed by said step-by-step means for selectively opening or closingsaid indication line circuit during each impulse period and during each time space period marked off on said stepping circuit by said impulse repeating relay, whereby said indication line circuit is impulsed andmessages are transmitted over said indication line circuit, said indication line circuit receiving energy for such impulses from'said source of current; another impulse repeating relay at the oice; a first message receiving relay and a second message receiving relay at the oiiice; means including said impulsing means and said another impulse repeating relay for reversibly inserting said first message receiving relay and said source of current in said indication line circuit during the impulse periods onfsaid stepping circuit de-` pending upon the polarity of the impulses on said stepping circuit and always inserting said second message receiving relayand said source of Current in said indication line circuit in thesarne anner'during said time spaced periods on `said ste Bing line circuits, whereby said common retum 'pe wire always acts as the return path for both sairline circuits; stick circuit means for said message gceiving relays alwayshaving current flowing in Ego same direction when energized; and, means s ntrolled` by said message receiving relays I'forfregisteringmessages transmitted by the selective imrlsing of said indication line circuit `j :f Y,

4. In a remote cntrol-jsystem; a control line circuit and an indica XOV line ,Circuit CORRECT/ing a control oiice and a field [Sta'pOIlgSaid 1111 Cilcuits having 9, common return line wire; a source of energy; a code transmitting, means for irnpressing a series -of positive and/01 IlegatVe time spaced impulses on said control line circuit from said source of energy; means at the eldtation responsive to said control impulses for receiving messages from the controloiICe; means at the field station responsive totli inpulseson said control line circuit for causing saidindicaticn line circuit to be selectively impulsed `in accordance with indication conditions atthe field station; a message-receiving relay atithe control ofce; means' controlled by said vcode transmitting means for reversibly connecting said message receiving relay and said source of 'energy in said indication line circuit, whereby said common return line always acts as the return path for the current of both said line circuits; stick circuit means for said message receiving relaysalways having current flowing in the same direction when energized; and means controlled by said message receiving relay in accordance with the impulses on said indication line circuit, whereby messages are received from the eld station.

5. In a remote control system; a control line circuit and an indication line circuit connecting a control office `and a field station, saidV line circuits having a common return line wire; a single source of energy in the control cnice; two code sending relays in the control oilice, one for applyinga positive impulse, whenrpicked up, and `the 'otherfor applying a negative impulse, rwhen picked up, from said source to'said control line circuit; means for selectively and intermittently controlling said two code sending relays inaccordance with a control message to be transmitted, whereby a series of time spaced positive and/orjnegative control impulses are placed on said control line circuit; means at the eld station responsive to said control impulses for receiving messages from'the control oice; means respon- `sive to the impulses on said control line circuit for` governing the distinctive impulsing of said indication line circuit inlaccordance with indication conditions at the field station both during the impulse periods and the time space periods stick circuits for said message receiving relays' for 'maintaining said relayspicked up until the end of the time periods next Vsucceeding-the time periods upon which they are respectively picked up, said stickicircuits always having current owing inthe same direction; and means distinctively controlled by said indication impulses4 aslirepeated by said message receiving relays, whereby indication messages are received `from the'eld station. Y.

6. In a remote control system; a control line wire and an indication line wire connecting a control oice and a field station, said line `wires included respectively in a control line, circuit and an indication line circuit having a common return line wire; aY single battery source in the` control ofce; `two* code sending relays in the controloice, one for applying a positive impulse, when picked up, andthe other for, applying a negative impulse, whenipicked up, from said bat-1 tery source to said control line-` circuit; means for selectively and intermittently controlling said two code sending relays in accordance with control messages to be transmitted, whereby diiiferent series of time spaced positive and/or negative control impulses are impressed on said control line circuit; code responsive means at the field station responsive to said control impulses for receiving messages from the control office; code transmitting means at the eld station governed in part by said code receiving means at the eld station and in part in accordance with indication conditions at the field station for distinctively impulsing said indication line circuit in accordance with indication messages to be transmitted. both during the impulse periods and the Y time space periods on said control line circuit;

twomessage receiving relays at the control office;

means controlled by said two code sending relays for reversibly connecting said battery source and one of said message receiving relays in said indication line circuit so as to apply positive or negative potential to said indication line circuit during each impulse period on said control line circuit dependng upon whether the impulse for that period on the control line circuit is positive or negativev in character respectively, and for connecting said battery source and said other mes- S356 receiving relay into said indication line circuit always in the same manner during the time space periods on said stepping line circuit; an impulse repeating relay in said control ofce for vrepeating each impulse on said control line circuit irrespective of its polarity; stick circuits for each 'of' said message receivingrelays, said stick circuits being governed in part by said impulse repeating relay and always having current flowing in the same direction; and means distinctively controlled by said indication impulses as repeated by said message receiving relay, whereby said indication messages are received from the field station.

7. In a remote control system; a control line circuit and an indication line circuit connecting a' control' oice and a field station, said line circuits having a common return line wire; a source of energy in the control oiflce; a code transmitting means at the control oice for impressing a series of postive and/or negative time spaced impulses on said control line circuit from said source of` energy; means at the eld station responsive to said control impulses for receiving messages from the control ofce; transmitting means at the eld station responsive to the impulses on said control line circuit for causing said indication line circuit to be selectively impulses in accordance with the indication conditions at the field station; a message receiving relay at the control office; means controlled by said code transmitting means at the control oiiice for reversibly connecting saidr message receiving relay and said source of energy in said indication line circuit, whereby said common return line wirealways acts as the return path for the current of both said line circuits, and whereby the current` alwaysflows through said message receiving relay 8. In a remote control system; a plurality of locations including a control oiiice and a field station; a steppingline circuit and an indication line circuit connecting the control oflice and the field station, said line circuits having a common return line wire; a source of current at said control oftlce; impulsing means at said control ofce for marking off a series of time spaced impulses on said steppping line circuit, said stepping line circuit receiving energy for said impulses from said source of current; an impulse repeating relay; step-by-step means at the eld station operated one step at a time in response to said series of impulses on said stepping line circuit as repeated by said impulse repeating relay; means governed by said step-by-step means for selectively opening or closing said indication line circuit during each impulse period and during each time space period marked off on said stepping line circuit by said impulse repeating relay; whereby said indication line circuit is impulsed and messages are transmitted over said indication line circuit, said indication line circuit receiving energy for suchl impulses from said source of current in said control oiiice; another impulse repeating relay at the office; a single message receiving relay at the oiiice; Ymeans including said impulsing means and said another impulse repeating relay for inserting said message receiving relay and said source of current in one relationship in said indication line circuit during each time space period and during each impulse ci one polarity but reversibly inserting said message relay in said indication line circuit during e" impulse of the opposite polarity, wherebyy Said message'receiving relay is always energied with current iiow inthe same direction irrefgl'gective of. the polarity of the impulses impresse upon Seid stepping line circuit, andiwhereby/eid messge receiving relay is responsive tof/the messages 40 transmitted over said indication/line circuit; and means controlled by said message receiving relay for registering themessages/transmitted by the selective opening and ,closi/h/g ef Said indication lille CI'CU 'during each/time VSpace and each i5 impulse period ofthe series, f

THOMAS J. JUDGE.

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