US2107163A - Centralized traffic controlling system for railroads - Google Patents

Description

Feb. 1', 1938. N. D. PRESTON 2,107,163 CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed May 16, 1936 2 Sheets-Sheet l Feb. 1, 1938. N. D. PREsToN' 5 CENTRALIZ ED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed May 16, 1936 2 Sheets-Sheet 2 Patented Feb. 1, 1938 UNITED STATES rArsr OFFICE CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Neil D. Preston, Rochester, N. Y., assignor -to General Railway Signal Company, Rochester, N. Y.

Application May 16, 1936, Serial No. 80,096

19 Claims. (Cl. 2463) This invention relates to centralized trafiic conof indications desired in the particular applicatrolling systems for railroads and it more particution.

larly pertains to a system of the non-coded or In the accompanying drawingsa complete comdirect control type as distinguished from a semunicating system is shown for transmitting con- 5 lector type system. trols and indications between a typical outlying 5 This invention is to be considered an improvefield station (illustrated in Fig. 2) and the associment over the prior application Ser. No. 741,626, ated central control oflice (illustrated in Fig. 1). filed August 27, 1934, by T. J. Judge, and no claim It will be understood that, in an actual installais made in tlL's application to subject matter comtion of this system, separate control circuits are 1 mon with suchprior application. required for each station, these circuits compris- 10 In accordance with the present invention it is ing a duplicate of the W, X, and Y lines illusproposed to provide means for controlling a retrated in the present drawings, with common wire mote power operated track switch by applying C serving as the common return. energy of selected polarity to a first line circuit A mid-tap battery OB is provided in the con- 35 at the control office and to govern the movement trol oifice and a mid-tap battery SB is provided of trafiic over this switch by applying energy of at the field station, with the mid-taps of these selected polarity to a second line circuit at the batteries connected together by commonwire C control office. as illustrated in the lower portion of the drawings.

It is also proposed to transmit signal indica- Atrack diagram is provided in the control ofiice tions from the remote location to the control office which corresponds to the associated typical track by applying energy of selected polarity to the section at the field station, by means of which first line circuit at the remote location and to the operator is readily advised as to the position transmit OS indications from the remote locaof the track switch, the condition of the assocition to the control ofiice by applying energy of ated signals, as well as the OS indications for the Z5 selected polarity to the second line circuit at the section of track with which the illustrated track remote location. switch is associated and two approach track Furthermore, switch indications are transmitsections. ted from the remote location to the control ofiice The circuit arrangement in the control office by applying energy of selected polarity to a third is shown in Fig. 1 and the circuit arrangement line circuit at the remote location. Approach inat the associated field station is shown in Fig. 2. 3 dications for two approach track sections are also Referring to Fig. 1, a signal control lever SGL transmitted over the third line circuit by applying is employed to set up the controls for the wayside energy of selected polarity to this line circuit at signals which govern trafiic over the illustrated the remote location. track switch. This lever is operable to three 33 These three line circuits are conveniently repositions, namely, west, stop and east as indicated 35 ferred to in the following description as the W by the reference letters W, S and E respectively. line, the X line and the Y line, with the C line Suitable contacts are indicated as being closed forming the common return for the other three when lever SGL is in either of its extreme operlin ated positions, with these contacts being open It is further proposed to provide such int rwhen the lever is in its center or stop position. 40 locking of the circuits in the communication of A SWltch Control level SML is p ov ed and controls and indications that the transmission of Operable to either of two positions for Setting up conflicting controls is prevented, with the system controls for associated switch macmne at retaining sufi'icient operating flexibility to permit fie1.d Statlon to posmon the I Switch to emcient governing of trams movements either its normal or reverse positlon. The two Other objects, purposes and characteristic fea-- posmons to Whlch lever SML can be Operated are l tures of the present invention W111 appear as the $5 2 :5 fi Ziggigfig? l fie zo if g i ate description progresses during which reference switch machine lever are preferably of the snap W111 be q to accmpaymg drawmgs action type so that they will be rapidly switched illustmw a dl agrammat 1c and Conventlonal from oneposition to the other irrespective of the manner one Speclfic embodlment of the Present speed of operation of the lever which controls invention, the arrangement of which may be th nt cts, mod fied in p a e depending on the ype of The OS lamp associated with the track diagram control required, the character of and the number is for the purpose of indicating to the operator 55 the occupied and unoccupied condition of the remote track section with which the illustrated track switch is associated. Approach lamps 1 AT and ZAT associated with the illustrated track diagram are for the purpose of indicating the occupied and unoccupied condition of approach track sections IA and 2A respectively.

Normal and reverse switch indicating lamps NI and RI indicate the track switch in its normal and reverse locked positions respectively by the illumination of the respective lamp. Neither lamp illuminated indicates that the associated track switch is either in its unlocked or midstroke position or that the switch is not in correspondence with the positionof lever SML.

Signal indication lamps ESK and WSK, associated with the track diagram, indicate the conditions of the associated signals ES and WS (also WSA) respectively at the remote location. The lumination of lamp ESK, for example, indicates that signal ES is'clear and the illumination of lamp WSK indicates that either signal WS or WSA is cleared.

Relay GK in the control office is the signal indicating relay which repeats the signal indications from the remote location in response to the control transmitted over W line. Relay G2 at the field station is the signal control relay which con trols the field station signals in response to the control transmitted over Y line.

Relay WK in the control ofiice is the switch position indicatingrelay which is operated in response to controls transmitted from the field station over X line. Relay WZ at the field station is the switch control relay which controls the associated switch machine in response to switch controls transmitted over W line.

Relays I'I'K and ZTK are the approach indication relays which are operated in response to approach indications transmitted from the remote station over X line. Rectifiers lR and 2R are for the purpose of transmitting the polarized current applied to- X line to the proper TK relay. Relay OSR is the OSR signal relay which controls the OS lamp in response to the condition of Y line when signal lever SGL is actuated.

Relays W and G in the control office are transfer nelays and are for the purpose of transferring the line circuits from one control to another as will be specifically pointed out later in the description. Relay T at the field station is the track relay associated with the track section with which the illustrated track switch is associated.

, Track relays T and T are associated with approach track sections IA and 2A respectively. Relays EM and WM are the signal indicating relays at the field station which are both energized as long as all illustrated signals are at stop. Although the control circuits for these relays are not shown it will be obvious that relay EM is deenergized when signal ES is cleared and relay WM is de-energized when either signal WS or WSA is cleared. Relay 'I'PX is a relay which responds to the simultaneous occupancy of both approach track sections and is for the purpose of transmitting polar impulses over X line for the purpose of operating the proper TK relay (or relays) in accordance with the condition of the approach track sections.

Suitable wayside signals ES, WS and WSA are indicated in the conventional manner as being of the light signal type for governing trafiic movements over the track switch TS. These signals are selectively cleared in accordance with the po sition of signal control relay GZ and in accordance with the proper position of the track switch as repeated by the contacts of correspondence relay WP, these contacts being included in the signal circuits, but which are omitted from the present drawings, since this portion of the circuit arrangement forms no part of the present invention and is immaterial for an understanding thereof. Relay WP is the usual switch position repeating relay which, when energized, indicates that the associated track switch is in its locked condition and which indicates this switch in its normal and reverse positions by its polar contacts being positioned to the right and left respectively.

In tracing the circuits during the following description of the operation of the system, and will be considered opposite terminals of a local source of energy OB at the control office and also of a similar local source of energy SB at the field station.

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, track switch TS is shown in its normal position for routing traific straight through on the main track in accordance with the normal position N of switch control lever SML. Normal switch indicating lamp NI is lighted to indicate that the switch is in correspondence with the switch machine lever. This energizing circuit for lamp NI extends from (-1-), contact I6 of lever SML in its normal position, lamp NI, contact ll of relay WK in its right hand (normal) position, front contact l2 of relay WK and winding of relay WK to (C).

All of the signals associated with the illustrated track section are shown at stop as indicated by contact I00 of relay GZ being in its dropped away position. This is in accordance with the center or stop position of signal lever SGL in the control office and since front contact I3 of relay GK is open, lamps ESK and WSK are de-energized.

Normal conditions-With the track sections at the field station unoccupied and with the control levers in the positions illustrated, the various devices, relays and circuits assume positions and conditions of energization as illustrated.

Track relays T, T and 'I are normally energized in the usual manner because it is assumed that the associated track sections are unoccupied.

With the switch machine in its normal locked position, relay WP is energized with current of a proper polarity for positioning its polar contacts to the right.

With all signals at stop, relays EM and WM are energized over circuits not shown. It will be understood that relays WZ, WP, GK and WK are of the polar neutral magnetic stick type, that is their neutral contacts assume dropped away positions when the windings of these relays are deenergized and assume picked up positions when their windings are energized. The polar contacts are assumed to be positioned to the right when current flows through the windings of the relays from left to right and positioned to the left when current flows through the windings of these relays from right to left.

they are last actuated when the windings of the relays are de-energized.

Operation of track switch-It will be assumed that the operator desires to reverse track switch TS in order to route traffic over the passing sid- The polar contacts are maintained in the positions to which ing and for accomplishing this purpose lever Sm is operated to its reverse position. The opening of contact ill of lever SML puts out the normal indicating lamp N1 and de-energizes relay WK. The de-energization of relay WK, following the actuation of the switch machine lever to its reverse position, closes a circuit for energizing W line with energy which extends from contact it of lever SML in its reverse dotted line position, back contact E5 of relay WK, winding of relay W, back contact it of relay G, W line conductor, back contact H6 of relay GZ, winding of relay WZ and front contact H5 of relay T to (C).

This energization of W line conductor picks up relay W in the control ofii'ce and relay WZ at the field station, actuating its polar contacts to the left. At contact ml of relay WZ, the normal control wire NC is ale-energized and the reverse control wire RC is energized for operating the switch machine to its reverse position.

During this operation of the switch machine, lamps N1 and RI are ale-energized as an indication that the track switch is not in correspondence with the switch machine lever. When the track switch assumes its reverse locked condition, relay WP is again energized and its polar contacts are actuated to the left. A circuit is now closed for energizing the X line with energy which extends from (C) winding of relay WK, front contact ll of relay W, X line conductor front contact iii of relay WZ, front contact 1 E8 of relay WP, contact H9 of relay WP in its left hand dotted position and contact ms of relay WZ in its left hand dotted position to In response to this energization of X line relay WK is energized and its polar contacts are positioned to the left. A stick circuit for relay WK is now established which extends from (C), winding of relay WK, front contact 12 and contact H in its left dotted position, lamp RI and contact 58 of lever SML to Since this stick circuit includes lamp RI, this lamp is illuminated as an indication that the track switch at the remote location is in its reverse locked condition in correspondence with lever SML in the control office.

The picking up of relay WK and the consequent opening of back contact 15 de-energizes W line and in response to this de-energization relays Wand WZ are lie-energized. The dropping of relay W in the control office de-ene-rgizes the X line conductor at open front contact if and relay WZ at the field station opens the X line conductor at front contact 9 H. Relay WK remains stuck up however over the above described stick circuit.

It will be understood that suitable "approach locking 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, since these circuits form no part of the present invention.

The operation involved in operating the track switch from its reverse locked position to its normal locked position is merely the reverse of the operation already described and will not be specifically pointed out. Such reverse operation may be understood by analogy, considering that lever SML, when returned to its normal position de-energizes the stick circuit for relay WK, after which W line conductor is energized with energy from contact M of lever SML which again picks up relays W and WZ, after which relay WK is again energized over X line and its stick circuit again established as normally indicated.

Signal confroL-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 in its east (right) position which closes a circuit for energizing the Y line with energy extending from contact 19 of lever SGL in its right hand dotted position, front contact 273 of relay WK, winding of relay G, Y line conductor, winding of relay GZ, contact I2! of relay WZ in its left hand dotted position, contact 622 of relay WP in its left hand dotted position, front contact N3 of relay WP and front contact lid of relay T to (C).

Relays G and G2 are energized by the current flow over Y line and relay G opens the circuit of relay OSR at back contact 2! before OSR has time to close its contact 24. The polar contact relay GZ is actuatecLto the right which closes a circiut for clearing signal ES extending from front contact I90 of relay GZ, contact iii? of relay GZ in its right hand position and through the various auxiliary circuits (not shown) to signal ES.

In response to the clearing of signal ES, relay EM is de-energized which closes a circuit for energizing W line with energy which extends from (C), winding of relay GK, front con tact it of relay G, W line conductor front contact 555 of relay GZ and back contact 1225 of relay EM to This energization of W line picks up the neutral contact of relay GK and positions its polar contact to the right. A circuit is now closed for lighting lamp ESK as an indication that signal ES is clear, which circuit extends from front contact 13 of relay GK, contact 23 of relay GK in its right hand position and lamp ESK to It is believed that the manner in which a signal may be cleared for traffic to the left over track switch TS is obvious from the foregoing description. However it will be briefly pointed out that the operation of lever SGL to the left applies energy by way of contact is in its left hand dotted position over the above described circuit including Y line conductor. Current flowing over this circuit picks up relay G, energizes relay GZ and positions its polar "contacts to the left, whereby a circuit is closed through contact it? in its left hand dotted position to clear signal WS or WSA. in accordance with the track switch is in its normal or reverse position respectively.

Track occupancy.Having described the manner in which the track switch is controlled from the control office and the signals are governed for traihc over this switch, it will now be assumed that a train enters the illustrated track section with which the illustrated track switch is associated, thereby dropping relay T.

The opening of front contact 524 of relay T de-energizes the above described signal control circuit including Y line wire which is efiective to de-energize relays G and GZ. The opening of contact 580 of relay GZ de-energizes the circuit leading to signal ES which puts this signal to stop.

The dropping of relay G de-energizes relay GK at open front contact 16, which causes front contact 53 to open and de-energize lamp ESK as an indication that the corresponding signal at the station is at stop. The de-energization of the circuit leading to lamp ES at the station causes relay EM to pick up and open the above described circuit including W line conductor.

A circuit is now closed for picking up relay OSR which extends from contact I9 of lever SGL in its right hand dotted position, front contact 259 of relay WK, back contact 2I of relay G and winding of relay OSR to (C). I"he picking up of relay OSR extends this circuit from by way of its front contact 24 and back contact 22 of relay W to lamp OS for lighting this lamp as an indication that the associated track section is occupied. It will be obvious that the circuit from contact I9 of lever SGL is not completed through the winding of relay G at this time because of open front contact I24 of relay T.

Track unoccupancy.--As soon as the train leaves the track section, relay T is picked up to energize Y line conductor with energy over the above described circuit and relay G is picked up. The opening of back contact 2I of relay G de-energizes and drops relay OSR which opens its front. contact 24 for de-energizing lamp OS as an indication that the associated track section is unoccupied.

Relays 'G and GZ are energized in response to the re-energization of Y line conductor and the closure of front contact I 00 of relay GZ again clears signal ES in the event that the signal lever at the ofiice has not yet been restored to its stop position. Relay EM is dropped in response to the clearing of signal ES and energy is again applied to W line conductor over the circuit previously described which includes back contact I25 of relay EM.

In response to the energization of W line conductor, relay GK is again energized to display signal ESK over the previously described circuit as an indication that the associated signal ES at the station is clear.

When the operator restores lever SGL to its stop position, Y line conductor is de-energized at open contact 19 which effects the de-energization of relays G and GZ. The dropping of relay GZ de-energizes the circuit to signal ES for putting this signal to stop, after which relay EM is again picked up.

The dropping of relay G de-energizes the W line circuit including relay GK, which effects the release of this relay for de-energizing lamp ESK.

Approach section 1A occupied.The present circuit arrangement provides means for energizing X line with energy in response to the occupancy of section IA at theillustrated field station. The occupancy of section IA causes relay T to be de-energized which closes a circuit for energizing X line with energy, which circuit extends from back contact I II) of relay TPX, front contact I I I of relay T back contact II2 of relay T back contact II! of re lay WZ, X line conductor, back contact I! of relay W, rectifier IR and upper winding of relay ITK to (C). Relay ITK picks up and closes a circuit at its front contact 25 for lighting lamp IAT as an indication that track section IA is occupied.

When section IA becomes unoccupied, relay T is picked up and the above described energizing circuit for X line conductor is interrupted at open back contact II2. This de-energizes relay ITK in the control omce which in turn puts out the indicating lamp IAT.

In the event that track section 2A is occupied, relay T is de-energized and X line conductor is energized with energy over a circuit ex tending from back contact II3 of relay TPX, back contact II4 of relay T back contact II I. of relay WZ, X line conductor back contact I! of relay W, rectifier 2R. and upper winding of relay 2TK to (C).

Relay 2TK is picked up and a circuit is closed at its front contact 25 for lighting lamp 2AT as an indication that the associated track section 2A is occupied. When relay T picks up in response to the unoccupancy of section 2A, the above described energizing circuit for X line is interrupted at open back contact H I which releases relay 2TK for putting out lamp 2AT.

In order to indicate both track circuits IA and 2A over the same X line circuit relays T and T control the energization of the indicating relays ITK and 2TK by opposite polarity, with rectifiers being used to render these relays responsive to polarity. The above description points out how indications are transmitted in response to the occupancy of both track sections one at a time and it will now be explained how the occupancy and unoccupancy of these track sections in various sequences effect the control of relays ITK and 2TK for giving the proper indications.

It will first be assumed that both track sections IA and 2A become occupied at the same time. When relay 'I is dropped in response to the occupancy of section 2A energy is applied over the above described circuit including X line and back contacts I I3 and I I4 of relays TPX and I respectively. Inasmuch as relays T and T drop away together, front contact III is opened before back contact II2 closes, so that there is no applied to the X line until after the application of energy. The simultaneous dropping of relays T and T completes a pick-up circuit for relay TPX through back contacts I26 and I21 of relays T and T respectively and back contact I28 of relay WZ. Since relay TPX is slow to pick up, the above described circuit for energizing X line with energy is completed for a substantial period of time before relay TPX picks up and opens back contact H3. When relay TPX picks up, because both relays T and 'I' are de-energized, the energy is cut off of X line and energy is at once applied. The energy applied to X line is effective to pick up relay 2TK and the energy applied to X line is effective to pick up relay ITK as above described. Relay 2TK is slightly slow to release so that the picking up of relay ITK closes a stick circuit for'relay 2TK before it releases, Which extends from front contact 21 of relay ITK, front contact 28 of relay 2TK and lower winding of relay 2TK to It is obvious that with relays ITK and 2TK both picked up the above described circuits for lighting lamps IAT and. 2AT are complete which gives an indication that both track sections IA and 2A are occupied.

In the event that track section 2A is occupied when a train enters section IA, relay T will be down and then when relay T drops, the energy applied through back contact I I4 of relay T for energizing relay 2TK is maintained until relay TPX opens its back contact II 3 to apply energy, by Way of its front contact MB and back contacts III and H2 of relays T and T respectively, to the X line for picking up relay ITK, after which relay 2TK is stuck up as before.

It will now be assumed that both sections IA and 2A are occupied and that the train leaves section IA first. The picking up of relay T opens the circuit leading to at back contact H2, which is effective to cause the release of both relays ITK and ZTK in the office before relay TPX at the station drops. When relay TPX drops, is applied to the X line conductor through back contacts H3 and E4 of relays TPX and T respectively, which causes relay ZTK to pick up and close the circuit for lighting lamp 2AT.

In the event that relay '1 picks. up first because the train leaves track section 2A first, then current is cut off of the X line at back contact I H until relay TPX drops, after which is applied to the X line by way of back contact Ht, front contact III and back contact M2 for picking up relay ITK over the above described circuit and this relay in turn lights lamp EAT.

It will be obvious that these approach indications are transmitted over the X line while relays W and WZ are de-energized, that is when no switch controls or indications are being trans mitted. In the event that the switch lever is shifted while an approach indication is displayed, the picking up of relay W closes obvious stick circuits at its front contacts 29 and 3!) for relays ZTK and ITK respectively. The picking up of relay WZ opens the pick-up circuit of relay TPX at back contact I28 so that if there is a change in the occupancy of the approach track circuits during the time the transmission of approach indications is interrupted, such change will be registered when W and WZ are again dropped.

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

Having described a traffic controlling system as one specific embodiment of the present invention, 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 further to be 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, what I claim l. Ina centralized traflic controlling system for railroads, a control office and a field station connected by a plurality of line wires, a switch control lever and a signal control lever at said office, a track switch and associated signals at said station, means controlled by the operation of said switch control lever for energizing a first line circuit including one of said line Wires, means responsive to the energization of said first line circuit for controlling the operation of said track switch, means controlled by the operation of said signal control lever for energizing a second line circuit including another of said line wires, means responsive to the energization of said second line circuit for controlling the operation of said signals, means responsive to the energization of said second line circuit for transferring said one linewire from said first line circuit to a third line circuit, means for transmitting indications of the conditions of said signals over said third line circuit, means for transmitting OS indications over said second line circuit, a stick relay having a stick circuit including a visual OS indicator, and a pick-up circuit for said stick relay controlled over said second line circuit by the transmitted OS indications.

2. In a centralized traffic controlling system for railroads, a control oflice and a field station connected by a plurality of line wires, a switch control lever and a signal control lever at said ofiice, a track switch and associated signals at said station, means controlled by the operation of said switch control lever for energizing a first line circuit including one of said line wires, means responsive to the energization of said first line circuit for controlling the operation of said track switch, means controlled by the operation of said signal control lever for energizing a second line circuit including another of said line wires, means responsive to the energization of said second line circuit for controlling the operation of said signals, means responsive to the energization of said second line circuit for transferring said one line wire from said first line circuit to a third line circuit, means for transmitting indications of the conditions of said signals over said third line cirouit, means for transmitting OS indications over said second line circuit, and means for transmitting indications of said switch positions over a fourth line circuit including a third one of said line wires.

3. In a centralized traffic controlling system for railroads, a control ofiice and a field station connected by a plurality of line wires, a switch control lever and a signal control lever at said office, a track switch and associated signals at said station, means controlled by the operation of said switch control lever for characteristically energizing a first line circuit including one of said line wires, means responsive to the character of energization of said first line circuit for characteristically controlling the operation of said track switch, means controlled by the operation of said signal control lever for characteristically energizing a second line circuit including another of said line wires, means responsive tothe character of energization of said second line circuit for characteristically controlling the operation of said signals, means responsive to the energization of said second line circuit for transferring said one a connected by a plurality of line wires, a switch control lever and a signal control lever at said ofiice, a track section and associated track switch at said station, signals associated with said track switch, means controlled by the operation of said switch control lever for energizing a first line circuit including one of said line Wires from a source of current at said oflice, means responsive to the energization of said first line circuit from, said source of current at said oifice for controlling the operation of said track switch, means controlled by the operation of said signal control lever for energizing a second line circuit including another of said line wires from said source of current at said office, means responsive to the energization of said second line circuit from said source of current at said oflice for controlling the operation of said signals, means including a relay at the control ofiice and another relay at the field station both responsive to the energization of said second line circuit for transferring said one line wire from said first line circuit to a third line circuit, means for transmitting indications of the condition of said signals over said third line circuit by energy from a source of current at said station, means for transmitting OS indications over said second line circuit by energy from said source at said control office, a stick relay, a pickup circuit for said stick relay controlled over said second line circuit in accordance with the OS indications transmitted, and a stick circuit for said stick relay controlled by the condition of energization of said first line circuit.

5. In a centralized trafiic controlling system for railroads, a control ofiice and a field station connected by a plurality of line wires, a switch control lever and a signal control lever at said office, a track section and associated track switch at said station, signals associated with said track switch, means controlled by the operation of said switch control lever for energizing a first line circuit including one of said line wires from a first source of current at said ofiice, means responsive to the energization of said first line circuit from said first source of current for controlling the operation of said track switch, means controlled by the operation of said signal control lever for energizing a second line circuit including another of said line wires from said'first source of current, means responsive to the energization of said second line circuit from said first source of current for controlling the operation of said signals, means responsive to the energization of said second line circuit for transferring said one line Wire from said first line circuit to a third line circuit, means for transmitting indications of the condition of said signals over said third line circuit from a second source of current at said station, means for transmitting indications of the condition of said track section over said second line circuit from said first source of current, a fourth line circuit including a third one of said line wires, means responsive to the ene-rgization of said first line circuitfrom said first source of current for preparing said fourth line circuit for the transmission of switch indications, and means for transmitting indications of the position of said track switch over said fourth line circuit.

6. In a centralized trafiic controlling system for railroads, a control oifice and a field station connected by a plurality of line wires, a switch control lever and a signal control lever at said ofiice, a track section and associated track switch at said station, signals associated with said track switch, means controlled by the operation of said switch control lever for energizing a first line circuit including one of said line wires from a first source of current at said office, a switch control relay responsive to the energization of said first linecircuit from said first source of'current for con trolling the operation of said track switch, means controlled by the operation of said signal control lever for energizing a second line circuit including another of said line wires from. said first source of current, means responsiveto the energization of said second line circuit from said first source of current for controlling the operation of said signals, means responsive to the energization of said second line circuit for transferring said oneline wire from said first line circuit to a third line circuit, means for transmitting indications of the condition of said signals over said third linecircuit from a second source of current at said station, means for transmitting indications of the condition of said track section over said second line circuit from said first source of current, a 5

fourth line circuit including a third one of said line wires, means responsive to the energization of said first line circuit from said first source of current for preparing said fourth line circuit for I,

the transmission of switch indications, and means in for transmitting indications of the position of said track switch over said fourth line circuit only when said switch control relay and said track switch are in corresponding positions.

7. In a centralized trafilc controlling system for 5 railroads, a control oifice and a field station connected by a plurality of line wires, a switch control lever and a signal control lever at said oflfice,

a track section and associated track switch at said station, an approach track section, signals asso 12o ciated with said track switch, means controlled by the operation of said switch control lever for energizing a first line circuit including one of said line wires from a first source of current at said,., ofiice, means responsive to the energization of said first line circuit from said first source of current for controlling the operation of said track switch, means controlled by the operation of said signal control lever for energizing a second line l.

circuit including another of said line wires from l) said first source of current, means responsive to the energization of said secondline circuit from said first source of current for controlling the operation of said signals, means responsive to the.

energization of said second line circuit for trans a;

ferring said one line wire from said first line circuit to a third line circuit, means for transmitting indications of the conditions of said signals over said third line circuit from a second source of current at said station, means for transmitting 4 line circuit including a third one of said line Wires. :5

8. In a centralized trafiic controlling system for railroads, a control office and a field station connected by a plurality of line wires, a switch control lever and a signal control lever at said ofiice H a track section and'associated track switch at go said station, a plurality of approach track sections, signals associated with said track switch, means controlled by the operation of said switch control lever for energizing a first line circuit including one of said line wires from a first source .2);

of current at said ofiice, means responsive to the energization of said first line circuit from said first source of current for'controlling' the oper ation of said track switch, means controlled by the operation of said signal control lever for en 9 ergizing a second line circuit including another 7 of said line wires from said first source of current, means responsive to the energization of said second line circuit from said first source of cur-l.

means responsive to the energization of said sec- 0nd line circuit for transferringsaid one line wire from said first line circuit to a third line circuit, means for transmitting indications of the, conditions of said signals over said third line circuit from a second source of current at said station, and means for transmitting indications of said approach sections over a fourth line circuit including a third one of said line wires.

rent for controlling the operation of said signals,

9. In a centralized traffic controlling system for railroads, a control oifice and a field station connected by a plurality of line wires, a switch control lever and a signal control lever at said office, a track section and associated track switch at said station, a plurality of approach track sections, signals associated with said track switch, means controlled by the operation of said switch control lever for energizing a first line circuit in cluding one of said line wires from a first source of current at said ofiice, means responsive to the enrgization of said first line circuit from said first source of current in controlling the operation of said track switch, means controlled by the operation of said signal control lever for energizing a second line circuit including another of said line wires from said first source of current, means responsive to the energization of said second line circuit from said first source of current for controlling the operation of said signals, means responsive to the energization of said second line circuit for transferring said one line wire from said first line circuit to a third line circuit, means for transmitting indications of the conditions of said signals over said third line circuit from a second source of current at said station, means for transmitting indications of said approach sections over a fourth line circuit including a third one of said line wires, and means for preventing the transmission of said approach indications when said first line circuit is energized from said first source of current.

10. In a centralized trailic controlling system for railroads, a control Mice and a field station connected by a plurality of line circuits, means including a switch control lever for distinctively controlling a track switch at said station by distinctively energizing a first one of said line circuits at said office, normal and reverse switch position indicating signals in said oifice, a switch position indicating relay in said office, means for distinctively energizing said relay from energy applied to a second one of said line circuits at said station in accordance with the position of said track switch, and circuit means both for sticking said relay and energizing the proper normal or reverse switch position indicating signal over circuits selected by said relay and said lever.

11. In a centralized traffic controlling system for railroads, a control ofiice and a field station connected by a first and a second line circuit, a switch control lever at said office arranged to control the operation of a track switch at said station over said first line circuit, a switch position indicating relay at said ofiice, a stick circuit for said switch position indicating relay arranged to be deenergized by a change in position of said lever, a pick-up circuit for said switch position indicating relay including said second line circuit and momentarily energized in accordance with the operated position of said track switch only when said track switch and said lever are in correspondence, means for energizing said stick circuit only when said lever and said switch position indicating relay are in correspondence, and switch position and correspondence visual indicating means energized over said stick circuit.

12. In combination, a control lever and a track switch connected by a first line circuit including one line wire, a switch position indicating relay associated with said lever and connected to a switch position indicator associated with said track switch by a second line circuit including another line wire, means for transmitting switch controls from said lever to said track switch over said first line circuit, means for transmitting switch position indications from said indicator to said switch position indicating relay over said second line circuit, a plurality of insulated track sections associated with said track switch, a plurality of track occupancy indicating relays associated with said control lever, a rectifier means, and means for transmitting track occupancy indications from said track sections to said track occupancy indicating relays over a third line circuit including said another line wire by way of said rectifier means.

13. In combination, a control lever and a track switch connected by a first line circuit including one line wire, a switch position indicating relay associated with said lever and connected to a switch position indicator associated with said track switch by a second line circuit including another line wire, means for transmitting switch controls from said lever to said track switch over said first line circuit, means for transmitting switch position indications from said indicator to said switch position indicating relay over said second line circuit, a plurality of insulated track sections associated with said track switch, a pluw rality of track occupancy indicating relays assonals to said signal indicators over a fourth line circuit including said one line wire.

14. In combination, a control lever and a track switch connected by a first line circuit including one line wire, a switch position indicating relay associated with said lever and connected to a switch position indicator associated with said track switch by a second line circuit including another line wire, means for transmitting switch controls from said lever to said track switch over said first line circuit, means for transmitting switch position indications from said indicator to said switch position indicating relay over said second line circuit, a plurality of insulated track sections associated with said track switch, a plurality of track occupancy indicating relays associated with said control lever, a rectifier means, means for transmitting track occupancy indications from said track sections to said track occupancy indicating relays over a third line circuit including said another line wire by way of said rectifier, signals associated with said track switch, signal indicators associated with said lever, means for transmitting signal indications from said signals to said signal indicators over a fourth line circuit including said one line wire, and means for transferring said one line wire from switch control to signal inzhcation transmission and said another line wire from switch position indication to track occupancy indication transmission.

15. In combination; a switch machine for operating a track switch; a control lever having two extreme positions for governing the operation of said switch machine to either of two extreme positions; indication means for indicating the position of said switch machine and the track switch; a polar neutral stick relay; a pick-up circuit for said stick relay closed only when and only momentarily each time said control lever and said indication means are operated into corresponding positions; stick circuit means for said stick relay including its own winding, its own neutral front contact and a contact on said control lever closed only when said lever and the polar contacts of said'stick relay are in corresponding positions; and a plurality of indicators selectively energized over said stick circuit means whereby a distinctive indication is displayed each time said control lever, said switch machine and the track switch are operated into corresponding positions and the displayed indication is annulled each time said control lever is moved to a new position.

16. In combination; a railway track switch; a plurality of signals for governing the movement of trafiic over the switch; switch and signal control relays adjacent the switch; a first wire, a second wire, a third wire and a common return wire extending from the switch to a remote point; switch and signal indication relays and electro-responsive selector means at said remote point; means for energizing the switch control and switch indication relays over said first and said second wires respectively and said common return wire when the electro-responsive means is deenergized; means for energizing the signal control relay and the electro-responsive means over said third wire and said common return wire; and means for energizing the signal indication relay over said first wire and said common return wire when the electro-responsive means is energized.

17 In a centralized traific controlling system for railroads, a control oflice and a field station connected by a first and a second line wire, control means including a switch control lever at said ofiice arranged to control the operation of a track switch at said station over a first line circuit including said first line wire, a switch position indicating relay at said oflice, a pick-up circuit for said switch position indicating relay including said second line wire and momentarily energized in accordance with the operated position of said track switch only when said track switch and said control means are in correspondence, a stick circuit for said switch position indicating relay energized only when said lever and said switch position indicating relay are in correspondence, switch position and correspondence visual indicating means energized over said stick circuit, means for at times switching said second line wire from said switch position indicating relay to a circuit portion including a trafiic condition receiving device, and means for energizing said circuit portion in accordance with trafiic conditions at said station.

18. In a centralized traffic controlling systeyn for railroads, a power operated track switch, switch control means including a control lever for governing the power operation of said track switch, a relay which must be deenergized to allow said control lever to govern said track switch, a pick-up circuit for said relay energized only when said track switch is in correspondence with said switch control means and only when said lever is capable of controlling said track switch, and stick circuit means for said relay deenergized by movement of said lever.

19. In a centralized traffic controlling system for railroads, a power operated track switch, switch control means including a lever for governing the power operation of said track switch, a polar-neutral relay which indicates the normal or reverse position of said track switch, a pickup circuit for said relay energized with one polarity or the other momentarily each time and only when said track switch operates into correspondence with the normal or reverse position of said control means, and stick circuit means for said relay energized only when said lever is in a normal or reverse position corresponding to the normal or reverse position indicated by said relay.

NEIL D. PRESTON.

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