US2145795A - Centralized traffic controlling system for railroads - Google Patents

Description

'r. J. JUDGE 2,145,795

CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Jan. 31, 1 939.

2 Sheets-Sheet l Filed Aug. 27, 193

ATTORNEY T. J; JUDGE 2,145,795

GENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Jan. 31, 1939.

Filed Aug. 27, 1954 '2 Sheets-Sheet 2 E vsmo; I

ATTORNEY Patented Jan. 31, 1939 PATENT OFFICE CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Thomas J. Judge, Rochester, N. Y., assignor to General Railway Signal Company, Rochester, N

Application August 27, 1934, Serial No. 741,626

11 Claims.

This invention relates to centralized traific controlling system for railroads and it more particularly pertains to a system of the non-coded or direct control type as distinguished from aselector.

type system. It is proposed in accordance with the present invention to provide means for, controlling a remote power operated track switch by selecting I the polarity of energy applied at the control oflice to one linecircuit and to control the movement of tra'fiic over this switch by selecting the polarity of energy applied to a second line circuit. It is also proposed-to provide a means for indicating over 'these rsame two line circuits the response of the track switch to the transmittedcontrol, the condition'ofthe traflic such as a signal clear or stop condition, the particular direction of traflic set up when a signal is clear and also the particular position and locked or unlocked condition of the track switch. Furthermore, it is proposed to indicate over these same line circuits the presence of a "train in the track section as well as to indicate the locked and unlocked conditions of the switch control circuits.

It 'is'further proposed to provide such interlocking of the circuits in the communication of "controls and indications that the transmission of conflicting controls'is prevented while the system retains sufiicient operating flexibility to permit efiicient governing of trafiic movements.

Other objects, purposes and characteristic fea- "tures of the invention willappear as the descripftion thereof progresses. During the description reference will be made to the accompanying drawings which illustrate in a diagrammatic and conventional manner one specific embodiment of the present invention which is susceptible of considerable modification .in practice, depending on the ty-pe of control required and the character and number of indications desired in the particular 7 application.

' In the accompanying drawings a complete communicating system is shown for transmitting controls and indications between a typical outlying field station and the controloffice which is associatedwith this station. It will be understood that in an actual installation of this system separate control circuits are required for each station,

these circuits comprising a pair of control line w'iresand a-comrnon return wire. These line wires are identified by reference characters WZ .GK. whichv indicate the switch control and the "signal indicating wire and GZWK which indi- Wire C serves as a common return for the above mentioned separate line conductors and it will be understood that this common return may also be used in connection with other circuits when desired.

It is contemplated that a track diagram corresponding to the associated typical track section to which this invention isapplied will be provided in the control ofiice but for the sake of simplicity in the drawings this'miniature track diagram has been omitted. It will be understood, however, that the indicating lights shown in the left hand portion of Fig. 1 will be so associated with the track diagram that the operator is readily advised as to the conditions of the track switch and the associated signals at the track section with which these lights are associated.

Fig. 1 indicates in a diagrammatic and conventional manner the circuit arrangement at the control oflice.

Fig. 2 illustrates in a diagrammatic and conventional manner the circuit arrangement at a typical field station.

Referring to Fig. l, a signal control lever SGL is employed to set up the controls for way-side signals governing trafiic over the track switch of 25 Fig. 2. This lever is operable to three positions, namely, right, stop and left indicated in Fig. l by the reference characters R, S and L respectively. Suitable contacts are indicated as being closed when lever SGL is in either of its extreme oper- 30 ated positions, with these contacts being opened when the lever is in its center or stop position.

A switch control lever SML is operable to either of two positions for setting up controls for the switch machine employed, to position the track switch in either its normal or reverse position. The two positions to which lever SML can be operated are normal and reverse as indicated by reference characters N and R respectively. The contacts of the switch machine lever are preferably of the snap action'type so that they will be rapidly switched from one position to the other irrespective of the speed of operation of the lever which controls these contacts.

Track occupancy lamp TK is shown, which is for the purpose of indicating the occupancy and unoccupancy of the track section illustrated in Fig. 2. Normal and reverse switch indicating lamps NWK and RWK, indicate that the track switch is in its normal and its reverse locked positions respectively, by the illumination of the respective lamp. When neither lamp is illuminated this is an indication that the switch is in its unlocked or mid-stroke position.

Lock lamp LK is lighted to indicate that the Relay WIP is the switch position indicating relay and relay WZP is a repeater of relay WIP. Relay LIP provides the electric lock equivalent feature which will be described later in the description. Relay LP in the office and relay WZ at the station are of the retained neutral, polar type and they serve the purpose of transferring the use of line conductor WZ-GK from switch indication to signal control. These two relays are indicated as being of the retained neutral type by the shaded portion of the relay winding. Such a relay maybe of any well known type, one example of which is indicated in the patent to F. C. Larson, No. 1,852,210 issued April 5, 1932.

Relays G12 and GZZ are the signal control relays. Relay GIP is the signal indicating relay. It will be understood that those relays which have a solid base line are of the slow acting type.

Referring to Fig. 2, relay WZ repeats the switch control as received over the line conductor WZGK and also functions as a transfer relay as above pointed. out. Relay WR is the relay which controls the switch machine circuit. Relays NCR and RCR are the normal and reverse correspondence relays respectively, controlled by relay WR and the switch repeating relay WP to indicate when the switch control circuits are in correspondence with the position of the switch machine.

Suitable way-side signals I, IA, 2 and 2A are indicated in the conventional manner as governing trafiic movements over the track switch TS. These signals are selectively cleared to govern traific by means of associated signal relays iG, IAG, 2G and ZAG. These signal relays are selected by the position of the signal control relay GZ in accordance with the proper position of the signal control relay GZ in accordance with the proper position of the track switch as indicated by the corresponding relay contacts which are included in these signal relay circuits.

Associated with the signal relays is a lock relay L which is normally energized and is deenergized whenever the signal control relay GZ is energized, the track relay T is de-energized or any one of the signal clearing relays is energized. The relays RM and LM are the conventional right and left direction repeating relays arranged in the local signalling circuits to be normally energized whenever their associated signals are at stop but to be de-energized whenever the associated signals display clear indications. Relay T is the conventionally arranged track relay associated with the normally energized section of track.

In pointing out the circuits throughout the description of the operation of the present invention, and will be considered opposite terminals of a local source of energy at the control oifice and also of a similar source of energy at the field station. (3+) and (B) will be considered opposite terminals of a source of energy at the control oflice and also of a similar source of energy located at the field station, each having a center tap (CN) connected to the common return conductor C.

It is believed that further description of the present invention will best be understood by considering the operation under certain characteristic or typical conditions.

Operation In the accompanying drawings the track switch TS is shown in its normal position for routing traflic straight through on the main track in accordance with the normal position N of the switch control lever SML. Normal switch indicating lamp NWK is lighted to indicate that the switch is in correspondence with the switch machine lever. the track section are shown at stop as indicated by relays lG, IAG, 2G and 2AG all normally deenergized; This is in accordance with the center or stop position of signal lever SGL in the control office and the illumination of lamp GK indicates to the operator that all signals are at stop.

Normal conditions.With the detector track section associated with track switch TS unoccupied by a train, with the control levers SML and SGL in the positions shown and with the track switch in its normal position as shown, the various devices relays and circuits assume positions and conditions of energization as illustrated.

Track relay T is normally energized in the usual manner. With the switch machine in its normal position, relay WP has its neutral contact picked up and its polar contact positioned to the left over the usual circuits.

With all signals at stop, relays HG, IAG, 2G and ZAG are de-energized which establishes a circuit for energizing relay RM extending from back contact It'll of relay HAG, back contact ID! of relay IG and winding of relay RM, to Relay LM is normally energized over a circuit extending from back contact H32 of relay ZAG, back contact I03 of relay 2G and winding of relay LM to A circuit is closed for energizing relay L extending from back contact Hi4 of relay ZAG, back contact I05, of relay 2G, back contact )6 of relay. IAG, back contact I91 of relay IG, back contact I08 of relay GZ, winding of relay L and front contact I09 of relay T, to

A circuit is closed for normally energizing relay NCR extending from front contact ill of relay WP, contact III of relay WP in its left hand position, winding of relay NCR, contact N2 of relay WR in its right hand position and front contact H3 of relay WR, to

A circuit is closed for energizing relay WR extending from (3+), contact E22 of relay WZ in its right hand position, front contact E23 of relay WZ, front contact i2 5 of relay L and winding of relay WR, to (CN).

A circuit is closed for energizing relay LP and positioning its polar contacts to the left (normal) and for energizing relay WZ and positioning its polar contact to the right (normal) extending from (B) switch machine lever contact it in its upper position, front contact H of relay LIP, back contact 12 of relay GZZ, winding of relay LP, back contact I 3 of relay GIZ, conductor WZGK, front contact H4 of relay RM, front contact H5 of relay LM, winding of relay WZ and front contact H6 of relay L, to (CN).

An auxiliary circuit is provided for the WZ GK line circuit through back contacts M!) and [41 of relays RCR and NCR respectively and front All'of the signals associated with.

the switch.

A circuit is closed for energizing relay WIP and positioning its polar contacts to the left '(normal) which extends from (B+), front contact Ill of relay NCR, front contact II8 of relay WZ, front contact II9 of relay T, conductor winding of relay WIP, to (CN).

Relay W2P is energized over a circuit extending I from front contact I5 of. relay WIP and winding of relay W2P, to Lamp NWK is normally lighted over a circuit extending from a front contact I6 of relay WIP, contact I! of relay WIP in its left hand position, lamp ,NWK and contact I 8 of lever SML in its upper position, to (B). A circuit is closed for lighting lamp GK which extends from back contact I9 of relay GIP and lamp GK, to

- 1 Relay LIP is energized over a circuit extending from (B+), front contact 20 of relay LP, back contact 2I-of relay GIZ, winding of relay'LIP,

contact 22 of relay WIP in its left hand position and contact 23'of lever SML in its upper position, to (ON). Operation of track switch-It will be assumed that the operator desires to reverse trackeswitch TS to'route traflic onto the passing siding and for accomplishing thispurpose lever SML is ,op-

: erated to its lower position The polarity applied to line conductor WZ-GK is thereby quickly reversed by the switching of contact III of lever SML, This reversal inv polarity is ineffective to drop the. neutral contacts of relays LP and WZ '7 but the polar contacts of these relays are operated to positions opposite from that indicated in the drawings.

-A circuit is now closed for positioning the polar contacts of relay WR to the left which extends from (B-), contact I22 of relay WZ in.

I itsleft h'and dotted position, front contact I23 of relay WZ, front contact I24 of relay L and winding of relay WR to (CN). The switching of contact I25 of relay WR operates the switch machine for placing the track switch in itsre-' verse position.

With the track switch in its unlocked position relay WP is de-energized which opens the above described circuit of relay NCR at front conis de-energized. 'The de-energization of both lamps NWK and RWK is an indication to the operator that the switch is unlocked.

When the switch reaches its reverse locked position a circuit is closed for energizing relay RCR j extending from front contact III) of relay ;WP, contact II I of relay WP in its righthand V dotted position, winding of relay RCR, contact I I2 of relay WR in its left hand dotted position and frontcontact II3 of relay WR, to

'A circuit is now closed for energizing relay WIP "and actuating its polar contacts to the right whichextends from (B), front contact I26 of relay RCR, back contact II! of relay NCR, front 'contact N8 of relay WZ, front contact II9 of'relay T, conductor GZ.WK front contact I4 of relay LP and winding of relay WIP, to (CN) A circuit is now closed for lighting lamp RWK as an indication to the operator that the switch is in its reverse lockedposition, which circuit extends from front contact I6 of relay WIP, contact I! of relay WIP in its right hand dotted position, lamp RWK and contact I8 of lever SML in its lower position, to (B).

The operation of contact 23 of lever SML from its upper to its lower position does not de-energize relay LIP because of a circuit closed with contact 23in its lower position which extends from (B+), front contact 20 of relay LP, back contact 2I of relay GIZ, winding of relay LIP, contact 22 of relay WIP in its right hand dotted position and contact 23 of lever SML in its lower position, to (CN) After the switching of contact 23 and before contact 22 of relay WIP is actuated to the right the above described circuit extends through front contact 24 of relay LIP, which contact bridges contact 22.

It will be understood that suitable approach locking means is provided in the control circuits for the switch machine SM but in order to simplify the present disclosure such locking means have been omitted from the drawings.

The operation involved in operating the track switch from its reverse locked position to its normal locked position is merely the inverse of the operation already described and will not be specifically pointed out. Such operation may be understood by analogy, considering that lever SML returned to the upper (normal) position reverses the polarity. upon line conductor WZGK and reverses the polar contacts of relays LP and WZ without dropping their neutral contacts. Relay LIP is maintained energized during this operation in a manner similar to that previously described.

Signal Control.It will now be assumed that the operator desires to allow a train movement from the main track to the right onto the diverging track over the track switch in its reverse position. The signal control lever SGL is moved to its upper (right) position which closes a circuit for energizing relay GIZ extending from (B+),

lie-energizes relay LIP for providing the electriclock equivalent which will be described in detail later.

The opening of back contact I3 of relay GIZ opens the energizing circuit of relays LP and WZ. The circuit through thefront point of contact I3 is not completed to the winding of relay LP because contact 26 of relay LP is in its right hand dotted position which opens the later to be described substitute circuit for relay LP. Relay LP therefore drops its neutral contacts and it will be recalled that its polar contacts are in their right hand dotted positions due to the reverse switch control which was transmitted over conductor WZ-GK.

The de-energization of relay LP opens front contact I4 which de-energizes relay WIP. With relays, LP and WZ de-energized a circuit is closed for energizing relays G2Z and GZ in series which extends from (B+), contact 21 of lever SGL in its upper dotted position, winding of relay G2Z,

back contact I4 of relay LP, conductor GZWK,

front contact H9 of relay T, back contact H8 of relay WZ, front contact I21 of relay RCR. and winding of relay GZ, to (CN). This is effective to position the polar contacts of relay GZ to the left (right signal). In the event that correspondence relay NCR is picked up when relay WZ is de-energized the circuit for relay GZ extends through front contact I41 of relay NOR. instead of contact I21 of relay RCR.

The opening of back contact I2 of relay GZZ opens the switch control circuit including the winding of relay LP. The opening of front contact I4 of relay LP opened the energizing circuit of relay WIP above described but a stick circuit for this relay is completed from (B), contact 23 of relay WIP in its right hand dotted position, front contact 29 of relay G2Z and winding of relay W IP, to (ON) for maintaining relay WIP in its last operated position. This prevents the dropping of relay WZP because front contact I5 of relay W HP is not opened.

Signal EA is cleared by the picking up of signal relay IAG over a circuit extending from front contact I28 of relay T, front contact I29 of relay GZ, contact I30 of relay GZ in its left hand position, front contact I3I of relay RCR and winding of relay IAG, to Contact E32 of relay IAG changes signal IA from a stop to a clear indication in the well known manner.

The opening of back contact I06 of relay IAG de-energizes lock relay L which further opens the energizing circuit of relay WZ at contact H6. The dropping of contact I24 of relay L provides the electric bias control for relay WR. so that this relay is maintained in its last energized position over a circuit extending from (B), contact I33 of relay WR in its left hand dotted position, front contact I34 of relay WR, back contact I24 of relay L and winding of relay WR, to (ON) The opening of back contact I00 of relay IAG de-energized relay RM. The dropping of relay RM closes a circuit for energizing relay GIP which extends from (B+), back contact N4 of relay RM, conductor WZ-GK, front contact I3 of relay GIZ, front contact 30 of relay WZP, back contact 3i of relay LP and Winding of relay GIP, to (ON) Relay GIP picks up its neutral contacts and actuates its polar contacts to the left. A circuit is now closed for lighting lamp RGK extending from front contact I9 of relay GIP, contact 32 of relay (HP, in its left hand position and lamp RGK, to The opening of back contact i9 de-energizes the circuit of lamp GK and the lighting of lamp RGK is an indication to the operator that a signal at the track section is clear for traffic to proceed to the right.

The manner in which a signal may be cleared for traffic to the left is obvious from the foregoing description, since the operation of lever SGL to its lower position applies (B) potential to the upper winding of relay GIZ for energizing this relay as before and for applying (B) potential to conductor GZ-WK through the windings of relays GZZ and GZ, which energizes these relays as before but positions the polar contact of relay GZ to the right instead of to the left. The above described circuit for the signal relay now extends through contact I38 in its right hand position and front contact I35 of relay RCR to relay 2AG.

The picking up of relay ZAG clears signal 2A by the actuation of contact I36. The opening of back contact I04 de-energizes relay L as before and the opening of back contact I02 de-energizes relay LM which applies (B) to conductor WZ-GK for positioning relay GIP to the right. This closes a circuit for lamp LGK which extends from front contact I9 of relay GIP, contact 32 of relay GIP in its right hand dotted position and lamp LGK, to

In the event that signal I is to be cleared with track switch TS in its normal position, then relay IG is energized over a circuit including contact I30 of relay GZ in its left hand (traffic to the right) position and front contact I31 of relay NCR to the winding of relay IG. Relay NCR would be picked up under this condition over the circuit previously described in connection with the normal circuit conditions. Contact I44 of relay I G clears signal I.

Signal 2 is cleared by the picking up of contact I38 of relay 2G when this relay is energized over a circuit including contact I30 of relay GZ in its right hand position and front contact I39 of relay NCR.

Track occupancy.I-Iaving described the manner in which the track switch is controlled from the control office and the signals are governed for traffic over this switch it will now be assumed that a train enters the illustrated track section thereby drop-ping relay T.

The opening of front contact I03 de-energizes the lock relay circuit so that the position of the track switch cannot be changed while the track section is occupied. It will be understood that the de-energization of relay L in response to the clearing of a signal previously described also looks the track switch against a change in position as long as a signal is clear.

The opening of front contact I28 of relay T de-energizes the circuit of the particular G relay which was energized so that all of these relays are de-energized for placing all signals at stop.

With all G relays de-energized, relays RM and LM are energized and since relay L is de-energized the circuit including line conductor WZGK is de-energized at front contact H3 of relay L. The de-energization of this line conductor drops relay GI P which is effective to again energize lamp GK at its back contact I9 as an indication that all signals are at stop.

The opening of front contact N9 of relay T obviously de-energizes relay G2Z which inturn de-energizes relay WIP by opening front contact 29. Front contact 33 of relay GIP is open at this time since relay GIP is de-energized as above pointed out.

A circuit is closed for lighting track occupancy lamp TK which extends from (B-]-) back contact 20 of relay LP, back contact 34 of relay WIP and lamp TK, to (B). The opening of contact I5 of relay WIP de-energizes relay WZP but due to the slow acting characteristics of the latter relay a circuit is momentarily closed for energizing the annunciator AN extending from back contact I5 of relay WIP, front contact 35 of relay WZP, back contact 36 of relay LP and annunciator, to It will be obvious that when the track becomes unoccupied, relay WIP picks up its contact I5 thereby opening the annunciator circuit before it is closed at front contact 35 of relay WZP so that the audible alarm is not given.

As soon as the train leaves the track section,

relay T is energized which returns the system to its normal condition as determined by the positions of the control levers SGL and SML and the circuit of lamp TK will be de-energized by the opening of back contact 34 of relay WIP.

It will thus be seen that the signals may be manually put to stop at the remote station by de-energizing conductor GZ-WK for dropping relay GZ at the station. This conductor is deenergized by contact 21 of lever SGL in its stop position if relay LP is de-en-ergized with back contact I4 closed. If relay LP is energized'then relay GZ cannot beenergized over conductor GZ-WK because the windings of relays W IP and GZ both connect to (ON) so that no circuit is made up for current toflow through either of these relay windings.

" The purpose of back contacts I20 and IN on relays LM and RM is to prevent the track occupancy indication being displayed at the same 7 time a signal clear indication is displayed. More l specifically, the track occupancy indication is 1 sent'in when contact N9 of relay T is opened and the signal clear indication is sent in by closing back contact I I4 or H5 of relay RM 01 relay LM. Therefore, opening front contact H9 will not send in a track occupancy indication as long as this contact is ,bridged'by either contact 7 I20 or 12! being closed due to relay LM or RM being'de-energized to transmit a signal clear indication. Thus, the track occupancy indication will not be displayed at the same time a signal clear indication is displayed.

-Electric lock equivalent-In the event that v lever SML is operated to a position out of correspondence with the contacts of relay WIP while the switch control circuit including relay LP is de-energized, then lever SML must be returned to a .position corresponding with the positions 7 of the contacts of relay WIP in order to effect 30 control conductor WZ-GK. This is because the the" control oftheswitch machine, even upon subsequent energization of relay LP and the dropping of relay LP. de-energizes relay LIP so that this relay cannot be again picked up, be-

cause of open front contact 24, until the switch machine lever contact 23 is in a position which corresponds to the position of contact 22 of relay-WIP. In other words, as soon as the signal lever is operated to a clear position for pick-- ing up relay GIZ, the opening of back contact 2| prevents a change in switch control until the 7 switch control lever is returned to the position which was last effective.

"With relay LIP de-energized, a circuit is closed for lighting lamp LK as an indication that the switch control circuits are locked, which circuit 'extends'from back contact 40 of relayLlP and lamp. LK, to Also, with relay LIP de-i-energized a circuit is closed for energizing I example, if this conductor is energized from (3+) through contact In of lever SML in its conductor WZ-GK with the polarity with which this conductor was last energized by the operation of switch machine lever SML. For

flower (reverse) dotted position, relay LP will actuate its polar contacts to the right (reverse) and upon the dropping of contact ll of relay Y LIP this polarity of energization is maintained by a circuit including contact 41 of relay LP in its right hand dotted position.

I be made even momentarily when the position of the switch lever is changed. Thistransfer must notbe made after the switch lever has been operated until the switch movement'has been completed even though the signal lever has been operated in the meantime.

More specifically, it will be assumed that the switch leveris operated and that the signal lever is qu ck yop e esl'ih eefi rr T e p a ion of The converse is true with lever SML in its upper po-- lever SGL energizes relay GI Z which opens conductor WZ-GK at back contact l3 but this circuit is not de-energized because of a circuit extendingthrough front contact l3 of relay GIZ, front contact 30 of relay W2P, front contact 3| of relay LP, contact 31 of relay WIP in its left hand position (normal), contact 26 of relay LP in its right hand dotted position (reverse) and through the winding of relay LP, to (3+) at contact ll) of lever SML over the previously described circuit. This is of course assuming that lever SML is operated from normal to reverse and that relay LP responds to close the above described circuit before relay WIP is de-energized.

When the switch starts its movement, relay WIP becomes de-energized because both correspondence relays NCR and RCR will be de-energized to open conductor GZWK at contacts Ill and I26. The dropping of relay WIP de-energizes relay W2P and the above described circuit through front contact l3 of relay GIZ is transferred by way of back contact 30 of relay WZP to the winding of relay LP for maintaining this relay energized.

When the switch has completed its movement relay WI P is energized to its reverse position and relay W2P is picked up over the local circuit through front contact l5. This opens the above described circuit at contact 37 in its right hand dotted position because contact 26 of relay LP is in its right hand dotted position. Therefore relays LP and WZ are both de-energized thus effecting the transfer of conductor GZ-WK from switch indication to signal control- Current now flows from (B) or (B+) depending upon the position of contact 21, through relay G2Z, back contact M of relay LP, conductor GZWK, front contact i I9 of relay T, back contact H8 of relay WZ, and front contact I21 of relay RCR to the winding of relay GZ. Current over this circuit is efiective to energize relays G2Z and GZ in series. With relay G2Z energized, relay WIP is held in a position to which it was last operated by the correspondence relay at the field station over a circuit including contact '28 of relay WIP.

The use of relay GIP for indicating the direction of traffic which is cleared by means of its contacts l9 and 32, as previously described, also provides another feature. A retaining (lower) winding is provided for relay GIZ which serves to hold this relay energized as long as an indication is coming in that a signal is clear even though the signal lever is restored to its stop position. For example, if a signal to the right has been cleared relay GIP will have its polar contacts actuated to the left as previously described. An energizing circuit is now completed for the retaining winding of relay GIZ extending from (3+), contact 38 of relay GIP in its left hand position, front contact 39 of relay GIP and lower winding of relay GIZ to (CN). It will be observed that the energization of this retaining winding is in the same direction as the energization of the upper winding of this relay by lever SGL in its upper (right) clearing position.

This arrangement provides a check that traific direction has been established at the field station in conformity with the position of the signal lever. If such conformity does not exist current flows through the two windings of relays GI Z in opposite directions thus tie-energizing the relay. For example, if lever SGL is actuated to its upper position, the upper winding of relay GIZ is energized from (B+) at contact 25 of the signal lever.

at the station is established for traffic to proceed to the left, relay GlP will have its polar con-' tact 38 positionedto the right which energizes the lower winding of relay GiZ from (B) thus causing relay GI Z to be de-energized. The opening of front contact 53 of relay GlZ de-energ-izes relay GIP which in turn de-energizes the lower winding of relay GlZ at front contact 39 thus allowing relay GIZ to again pick up. This produces a cycle of operations of relays GI Z and GlP which causes the sigal indication lamps to flash by the continued switching of contact 19 of relay GiP as an indication that conformity does not exist between the signal lever and the trafiic direction established at the station.

It will be noted that the dropping of track relay T or correspondence relay NCR, with the circuits in the condition shown, de-energizes normally energized relay WIP. It will also be noted that normally energized relay LP is de-energized when the track section is occupied because the opening'of front contact I09 of relay T de-energizes relay L. Relay L opens its front contact H6 to de-energize the line conductor in which relay LP is included. Therefore relay LP effects the energization of the track occupancy lamp TK and the switch position indicating lamp NWK or RWK when relay WIP is de-energized. In addition to this the switch position indicating lamp circuits are de-energized whenever the switch machine lever and relay W! P are not in correspondence and these lights remain dark when the lever is moved until the switch has completed its movement and is in correspondence with the lever position.

It is to be understood that although only one specific embodiment of the invention has been disclosed, the principles set forth may be app-lied to various other types of systems. and various complicated track layouts may be controlled in a similar manner, since the present disclosure is chosen merely for the sake of simplicity andclearness in describing the invention.

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

Having described my invention, I now claim:

1. In a railway traffic controlling system, a control office and a field station connected by a first and a second control line wire, switchcentrolling means for controlling a track switch at said station by energizing said first control line wire at the control ofiice, signal clearing means for clearing a signal at said station by energizing said second control line wire at the control office, switch and signal indicating means at said office, means for initially connecting said second control line wire to said switch indicating means only when said first control line wire is energized, and means for connecting said first control line wire tosaid signal indicating means only when said first control line wire is deenergized.

2. In a railway trafiic controlling system, a control ofiice and a field station: connected by a first and a second control line wire, signal control Ifrelay GIP indicates that the trafiic direction means at said office, means for controlling a track switch at'said station by energizing said first control line wire at the control office, means for clearing a signal at said station by energizing said second control line wire at the control ofilce, switch and signal indicating devices at said oflice, means for initially connecting said second control line wire to said switch indicating means only when said first control line wire is energized, means for connecting said first control line wire to said signal indicating means only when said first control line. wireis deenergized, and means at said control ofi'lce for connecting said second line wire to said signal control means only when said first control line wire is deenergized.

3. In a centralized traflic controlling system for railroads, a control ofiice, a field station, a track switch at said field station, a power-operated switch machine for operating said track switch, signals for governing trafiic oversaid track switch,

a switch control relay at said field station for governing the operation of said switch machine,

a signal control relay at said field station for governing the operation of said signals, a. switch control lever and a signal control lever at said control ofiic'e, a'switch indicating relay and a: signal indicating relay at the control ofiice, one control line wire normally connecting said switch control lever and said switch control relay, another control line wire normally connecting said switch indicating relay and contacts controlled by said track switch, means effective when said signal control lever is in one position and responsive to the deenergization of said one control line wire to connect said signal control lever and signal control relay by said another control line wire, and means effective when said signal lever is in one position and responsive to the energization of said another control line wire to connect said signal indicating relay and contacts operated by said signals over said one control line wire.

4. In a centralized trafiic controlling system for railroads, a control office, a field station, a track switch at said field station, a power-operated switch machine for operating said track switch, signals for governing trafiic over said track switch, a switch control relay at said field station for governing the operation of said switch machine, a signal control relay at said field station for governing the operation of said signals, a switch control lever and a signal control lever at said control ofiice, a switch indicating relay and a signal indicating relay at the control ofiice, one control line wire normally connecting said switch control lever and said switch control relay, another control line wire normally connecting said switch indicating relay and contacts controlled by said track switch, means effective when said signal control lever is in one position and responsive to the deenergization of said one control line wire to connect said signal control lever and signal control relay by said another control line wire means effective when said signal control lever is in another position and responsive to the energization of'said another control line wire to connect said signal indicating relay and contacts controlled by said signals over said one control line wire, a relay for causing the deenergization of said one control line wire, a pick-up circuit for said relay closed whenever said signal lever is in an operated position, and a holding circuit for said relay closed whenever said signal indicating relay indicates the clear condition of said signals.

5. In a centralized trafiic controlling system for railroads; acontrol ofiice; a field station; a powerretained-neutral polar type at said field station; a switch control lever at said control ofiice; a line repeating relay of'the retained-neutral-polar type at said control ofi'ice; one control line wire connecting said switch control lever, said switch control relay and said line repeating relay in series, so that operation of said switch control lever toan opposite position reverses the polarity of current in said one control line wire to cause the operation of said track switch to an opposite position; an-

-other control line wire connecting said'control oflice and said field station; means including neutral contacts of said switch control and line repeating relays for connecting said another control line wire to one set of devices when said re tained-neutral-polar relays are energized and for connecting said another control line wire to an- ;other set of devices when said relays are deenergized; and means for at times deenergizing said one control line wire; whereby the reversal of polarity in said one control line wire by said switch control lever is inefiective to shift the con- 0 Y nection of said another control line wire from one set of devices to the other but wherebythe deenergization of said one control line wire by said last named'means effects a shift of the connection of said another control line wire from one set of devices to the other. j 6. In combination, a power-operated track switch, a switch control lever for governing the power operation of said track switch, signals for governing traffic over said track switch, a signal control lever'for clearing said signals when operated to a clearing position, a single winding lock relay having a front contact for allowing said switch control lever to govern said track'switch only when such contact is closed, a pick-up cirquit for said lock relay capable of being closed only when saidswitch control lever is in a position corresponding to the actual position to which said track switch was last'operated, a stick circuitfor said lock relay capable of being closed independentlyof the position of said track switch, and means for opening both said pick-upand a stick circuits whenever said signal lever is in a "signal clearing position and so long as any one of saidsignals is clear.

7. In a railway traific controlling system, a

a control office and a field statio-n connected by a first control line wire and a second control line wire, switch controlling, means for controlling a track switch at said station by energizing said first control line wire at the control oflice, signal clearing means for clearing a signal at said station by energizing said second control line wire at the control office, switch and signal indicating means at said ofiioe, means for initially connecting said second control line wire to said switch indicating means only when said first control line wire is energized, means for connecting said first control line wire to said signal indicating means only when said first control line wire is deenergized; and means controlled by said signal clearing means for effecting said de-energization of said first control line wire. I

8. In a centralized trafiic controlling system for railroads, a control oflice and a field station connected by a first and a second control line wire,

a switch control lever and a signal control lever at said ofiice, a track switch and associated signals at said station, means responsive to the operation of said switch control lever for controlling the operation of said track switch over of one polarity or the e by a relatively quick change the operation of said signal control lever for controlling the operation of said signals over said second control line wire, a relay, a circuit for said relay energized by the operation of said signal lever to a signal clearing position independently of the energized or deenergized condition of said line wires, contacts controlled by said relay for transferring said first line wire from a switch control to a signal indication circuit at said control ofiice, and means for transmitting signal indications over said first line wire.

9. In combination, a power operated track switch, a switch position indicating relay controlled in accordance with the position to which said track switch is operated, a switch control lever for governing the operation of said track switch, signals for governing traflic over said track switch, a signal control lever for clearing said signals when operated to a signal clearing position, a single wound lock relay having a front contact for allowing said switch control lever to govern said track switch only when said contact is closed, a pick up circuit for said lock relay capable of being closed only when said switch control lever is in a position corresponding to the'last operated position of said track switch as indicated by said switch position indicating relay, a stick circuit for said lock relay capable of being closed independently of the position of said track switch, means for opening both said pick up and said stick circuits whenever said signal lever is in a clearing position and so long as any one of said signals is clear whereby said lock relay is deenergized, and means visually indicating when said lock relay is deenergized.

10. In combination, a polarized line circuit connecting a control office and a field station, a retained-neutral-polar relay included in series in said polarized line circuit at the control ofiice and another such retained-neutral-polar relay included in series in said polarized line circuit at thefield station, means at the control office for energizing said polarized line circuit with current other in accordance with the position of a control lever, a traific controlling device at the field station controlled in accordance with the polarity of current in said polarized line circuit as repeated by said another retainedneutral-polar relay, another line circuit connecting the control ofiice and the field station and including a front neutral contact on each of said retained-neutral-polar relays for completing such another line circuit, electro-responsive means controlled over said another line circuit, wherein the direction of current flow in said polarized line circuit does not interrupt the continuity of said another line circuit.

11. In combination, a first line wire connecting a control ofiice and a field station, a retainedneutral-polar relay at said oifice and at said station included in series in said first line wire, means at the control ofiice for determining the direction of current flow in said first line wire, a trafiic controlling device at the field station controlled in accordance with the direction of current fiow in said first line wire as repeated by the retained-neutral-polar relay at said field station, another line wire connecting the control oflice and field station, means including front contacts on both said retained-neutral-polar relays for closing an indication circuit over said another line wire when said first line wire is energized,

means including back contacts on both said. retained-neutral-polar relays for closing a control circuit over said another line wire only when continued. deenergization of said polarized line Wire is effected, and means for at times effecting continued deenergization of said polarized line wire,

whereby a relatively quick change in the direction of current flow in said first line wire is ineffective to momentarily interrupt said indication line circuit.

THOMAS J. JUDGE.

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