US3836768A - Centralized traffic control system for railroads - Google Patents

Centralized traffic control system for railroads Download PDF

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Publication number
US3836768A
US3836768A US00291519A US29151972A US3836768A US 3836768 A US3836768 A US 3836768A US 00291519 A US00291519 A US 00291519A US 29151972 A US29151972 A US 29151972A US 3836768 A US3836768 A US 3836768A
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United States
Prior art keywords
control
track
indication
switch
field
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US00291519A
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English (en)
Inventor
J Clarke
J Jacobus
E Lager
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SASIB SpA
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General Signal Corp
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Application filed by General Signal Corp filed Critical General Signal Corp
Priority to US00291519A priority Critical patent/US3836768A/en
Priority to CA176,608A priority patent/CA961969A/en
Priority to ZA737224*A priority patent/ZA737224B/xx
Priority to NL7312631A priority patent/NL7312631A/xx
Priority to AR250182A priority patent/AR200497A1/es
Priority to FR7334022A priority patent/FR2208812B1/fr
Priority to MX006107U priority patent/MX3060E/es
Priority to AU60558/73A priority patent/AU486463B2/en
Priority to IT7329272A priority patent/IT1001550B/it
Priority to GB4462773A priority patent/GB1452328A/en
Application granted granted Critical
Publication of US3836768A publication Critical patent/US3836768A/en
Assigned to SASIB S.P.A. reassignment SASIB S.P.A. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: GENERAL SIGNAL CORPORATION, A CORP. OF NEW YORK
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L25/00—Recording or indicating positions or identities of vehicles or trains or setting of track apparatus
    • B61L25/06—Indicating or recording the setting of track apparatus, e.g. of points, of signals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L21/00—Station blocking between signal boxes in one yard
    • B61L21/06—Vehicle-on-line indication; Monitoring locking and release of the route
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L27/00—Central railway traffic control systems; Trackside control; Communication systems specially adapted therefor
    • B61L27/20—Trackside control of safe travel of vehicle or train, e.g. braking curve calculation

Definitions

  • ABSTRACT A centralized traffic control system for governing from a central office a plurality of groups of track switches and signals which are disposed along a stretch of railway track.
  • a plurality of switch means designates a selected control for any switch or signal in any selected group.
  • an indication storage means is provided at the central office which is responsive to the conditions of the track switches and signals at each of the field stations and also responds to indicate the occupancy of the associated trackway.
  • the indication storage means may drive a cathode ray tube display.
  • An electonic digital computer which includes means for storing a program comprising a plurality of subroutines each of which is associated with a corresponding one of the groups of switches and signals, also known as field stations.
  • a program comprising a plurality of subroutines each of which is associated with a corresponding one of the groups of switches and signals, also known as field stations.
  • I8 I9 40 Location Address WN WR 6N GS GB '82 4
  • FIG. 7 H Switch lsorresgonaence Set Deloyed Code Start Request Reset South Sig nol Coll Set North Signal Coll Reset North 4 Signal Coll 1 Signal Call 306 Set Signal Stop 00 ll Reset North Slqnol Call 307 l Reset Code Set South Stort Request Reset Siqno I -3OO Stop Coll Reset Delayed Code Start Request FlG.7C.
  • the central office includes not only a plurality of levers and switches for designating a particular control at any selected one of the field stations, but also comprises indication means for designating visually the status at each moment of each of the various switches and signals at the various field stations as well as indicating those track sections along the trackway which are at any time occupied by a train.
  • the present invention provides a centralized traffic control system wherein electronic digital computer techniques are provided in connection with the transmission of controls from central office to field stations, the receipt of indications from the field stations, and the display of indications on a visual display means.
  • the present invention contemplates that, instead of providing an elongated display panel on which is displayed the conditions of the entire stretch of railway track in question, there will be provided for an operator instead a plurality of cathode ray tube displays, at least one of which will indicate the general layout of the tracltway for the system and will thus constitute, in effect, a fixed display, while a further cathode ray tube displays thereon the layout of the trackway and the location of the switches and signals for a particular siding, or even more particularly for a particular end of a designated siding.
  • a keyboard Associated with the cathode ray tubes is a keyboard on which the operator may designate that particular siding or siding end which he wishes to view at any time.
  • the electronic computer apparatus of the invention Upon appropriate actuation of the keys, the electronic computer apparatus of the invention will retrieve from a memory the desired display to appear on the cathode ray tube, and distinctive indications will be provided on such tube to indicate not only the operated conditions of the track switches and signals at the particular called-for location but also the occupancy of the track section or sections which are associated with that siding.
  • the apparatus of this invention also provides that, through the use of electronic computer techniques, the permissibility of a designated control will be checked prior to transmission thereof to a designated field station. More particularly, the storage apparatus associated with the electronic computer will store therein a plurality of decision tables, each of which is associated with a particular field station. When the operator designates a particular field station as the intended recipient of a control for a switch, signal, or the like, the decision table appropriate to that particular designated field station will then be designated, such sub-routine being the one which is peculiar to the particular switch or signal which is to be operated.
  • each field station will be interrogated and an indication will be transmitted from such interrogated field station back to the central office. It is further contemplated that such received indication code will be checked with the information then already stored in the indication storage means of the computer to determine whether any change in the indication has taken place. Upon the detection of such a change, an appropriate processing will take place so that ifa display of that location is called for it will indicate up-to-date information.
  • FIG. 1 is a perspective drawing of a typical operators console
  • FIG. 2 illustrates the various keys on the keyboard comprising a part of the apparatus of FIG. 1'
  • FIG. 3 is an enlarged view of the three cathode ray tube displays which are made available to the system operator;
  • FIG. 4 is a general block diagram of the apparatus of the invention.
  • FIG. 5 is a flow chart for the centralized traffic control system program routine of this invention.
  • FIG. 6A is a representation of a portion of the indication file
  • FIG. 6B is a representation of a portion of the control file
  • FIGS. 7A and 7B are, respectively, flow charts of the maintainer call on and off routines of the decision table
  • FIGS. 7C and 7D are, respectively, flow charts ofthe switch reverse and switch normal routines of the decision table
  • FIGS. 7E and 7F are, respectively, flow charts of the signal north and signal south PB routines of the decision table
  • FIG. 70 is a flow chart of the signal stop PB routine of the decision table
  • FIG. 7H is a flow chart of the switch correspondence routine of the decision table
  • FIG. 7 is a flow chart of the switch track occupancy indication change routine of the decision table
  • FIG. 8 is a track plan for locations 40, 41 and 42',
  • FIG. 9A shows the different switch display configurations
  • FIGS. 9B and 9C are respectively, displays for switch normal and switch reverse conditions
  • FIG. 9D illustrates a signal cleared over a reversed switch with track occupancy
  • FIG. 9E is a flow chart for the display routine.
  • FIG. 1 A typical operators console is shown in FIG. 1.
  • This apparatus comprises a desk-like console 10 on whose upper surface are supported three separate viewing screens 12, 14, and 16, and a keyboard 18.
  • An operator positioned at the console has displayed before him on the viewing screens 12 and 16 a visual display of the entire trackway under his control together with indications concerning the presence of trains on the trackway.
  • On the center display screen 14 is displayed an enlarged portion of the trackway, which enlarged portion may comprise, for example, a single siding or perhaps even only one end of a single siding.
  • the particular trackway configuration displayed thereon corresponds to a preselected portion of the overall trackway displayed on the two outlying screens 12 and 16.
  • the portion which is to be shown in greatly enlarged form on the center screen 14 is selected by the operator by appropriate designation on the keyboard 18.
  • the operator designates a particular siding or end of a siding to be displayed on the center panel 14, he may call up such display and there will then be displayed on the center screen 14 not only the track configuration but also the locations and conditions of the switches and signals associated therewith as well as the occupancy conditions of the associated track sections.
  • FIG. 2 A detailed illustration of the arrangement of the keyboard 18 of FIG. I is shown in FIG. 2.
  • a plurality of keys is illustrated much in the manner of a typewriter keyboard except that the key layout is different from that of a standard typewriter.
  • the key at the right-hand side and at the topmost row is designated as LOC.
  • the next lower row of keys is provided a series of keys for each of the ten digits from zero through nine.
  • the row of keys just mentioned is used in combination with the LOC key 20 in the following manner.
  • the operator will then first depress the numbered keys 1 through 0 in accordance with the field station or location to be selected.
  • the first step will be to depress the LOC key 20 and thereafter to depress the keys numbered 4 and l in that order in the topmost row of numbered keys.
  • FIG. 3 shows that the center display unit 14 may be so arranged as to display thereon theconfiguration of the end only of a single siding, and it will be understood that this will generally involve only a single track switch.
  • the system is not intended to be limited to this but, may instead be arranged so that the center display tube will display thereonan entire siding and/or one or more crossovers, etc. in which event a plurality of switches and signals will be displayed. It is for this reason that the second row of keys on the keyboard of FIG. 2 provides for thedesignation of switch normal and switch reverse controls to as many as five different switches.
  • the pair of keys 28 and 30 is required, key 28 upon actuation initiating a controlfor switch'l to be normal, and key 30 upon actuation initiating a control for switch 1 to be operated to thereverse condition.
  • control keys lncludedalso in the second row of control keys are a-key26 which will designate that the snow-melting apparatus at'thefield station is to be placed into operation, and a further key 48 which designates at a selected "field station a maintainer call directing maintenance personnel to call in for instructions.
  • the third row of keys in FIG. 2 is provided for the control'of-the signals at afield station, and each of these keys 50, 52,34, 56 and 58 is associated with a pair of related keys in the next row below.
  • key 50 designating thatsignal l is to be controlled to display a stopjndication is associated with keys 60 and 62.
  • the three keys 50, 60 and 62 provide for the transmission of controls to signal '1 'to display, respectively, .a-stop indication, a clearing of signal 1 forieftboundwtraffic, and a clearing of signal 1 for right-bound traffic. Similar groupings of three keys are shown in FIG. 2, each one associated with a different signal.
  • FIG. 4 shows in block diagram form control apparatus for an entire CTC system.
  • the apparatus at the control office (enclosed in the dotted line 100) provides the capability of controlling each of aplurality of field stations in a CTC system, in this case, FSl-FSN.
  • Each of the field stations,FSl, PS2 FS'N receives control signals, over the communication line wires 101 to control the respective switches and signals at that location in response to the received controlsignals.
  • the field stations send indications to the central ot'fice,.again via communication line wires 101, in accordance with the actual operatedposition of switches and the condition of the signals at that location. Since applicant'sinvention is not directed to novel field station apparatus, no further description of the field station apparatuswillbe given here, and reference is made to US. Pat. 'No. 2,907,980 for a description of such a conventional field station.
  • the apparatus at the central office 100 can be broken down functionally into three subsystems.
  • the first subsystem is ahuman-machine communication system
  • the second is a control office-field station communication system
  • the third is the decision making apparatus responsive to the other two subsystems to perform the necessary logical functions.
  • the human-machine communication subsystem comprises the CRT display 102 and the control keyboard 103, which is shown in more detail and explained with reference to FIG. 2.
  • Control keyboard 103 may be a standard keyboard which converts depression of a key into electrical signals representative of that key.
  • the signals generated by the control keyboard act as inputs to the logical apparatus of the third subsystem.
  • the human operator In order for the human operator to control intelligently the apparatus in the field station through his operation of the control keyboard, he must have up-to-date information onthe condition of particular switches, signals, and location of the trains in the system.
  • the CRT display 102 is provided which is enabled to display the conditions at a particular location, when directed by proper operation of the controlkeyboard, through operation of the third subsystem which, in storing information about each location, is capable of controlling the CRT 102 to display the information from any selected location.
  • the second subsystem is a field station-central office communication system which is representedby code converter 104.
  • This apparatus receives control signals as generated by the decision making subsystem, converts them for efficient transmission over communication wires 10] and for proper reception at the particular field stations.
  • the code converter In addition to transmitting control signals from the third subsystem to the field station, the code converter also receives indication signals from these field stations and transmits them to the third subsystem, the logical apparatus.
  • the third subsystem which has been termed the logical apparatus, has beenshown, for ease of representation, as a central processing unit 105 with its internal memory 106 and an additional bulk memory 107.
  • the central processing unit 105 may be characterized as the hub of the entire system, receiving information from a number of devices with respect to desired controls, receiving field station indications, performing the necessary logical functions in order to generate the proper control signals, and properly storing the information received from the field stations so that it is retrievable.
  • the central processing unit 105 performs all of these functions as directed by a program designed to direct it to respond properly and perform the necessary functions, which program will be described in detail later.
  • the central processing unit 105 and its internal memory 106 have been shown enclosed for the reason that they are generally manufactured, sold and used as a unit. Applicant had found that the Nova Computer Model 1200, manufactured by Data General Corp. is suitable for the present purposes. This is generally referred to as a "mini computer by reason of its word length of 16 bits. Other minicomputers could be used instead of the Nova and indeed, a full size computer, i.e. one whose word length is 32 bits and up, could be used instead. By reason of its limited internal memory 106, applicant finds it necessary to employ an auxiliary bulk memory 107.
  • the particular Nova computer used by applicant has an internal memory composed of ferrite cores. This is not essential to applicants invention and other internal memories could be used, such as solid state memories. Furthermore.
  • Each of the devices connected to the central processing unit I is treated by that unit as either input. output, or input/output.
  • the keyboard is an input unit
  • the CRT display is an output unit
  • the code converter and auxiliary bulk memory 107 are input/output units.
  • FIG. 5 is a flow diagram for the portion of the program which responds to signals related to the operation ofthe CTC system itself, as opposed to basic computer operating and house keeping signals designed to enable the machine to coordinate its activities.
  • FIG. 5 it will first be helpful if we consider how the computer memory is allocated, both the internal memory and the bulk memory and how the system generally operates.
  • the chart below illustrates that the internal memory of the computer is allocated to contain a number of tables and files, in addition to the program.
  • Control File Code Start (FIG. 68) File The program sequencer has reference to the operating system which will not be further described as it forms no part of applicants invention.
  • the CTC routine is shown in FIG. 5.
  • One of the files located in the internal memory is allocated to store at any time one of a plurality of decision tables. At this point it should be noted that a different decision table is provided for each field station.
  • all decision tables are located in the bulk memory. Only when a particular decision table is needed is it loaded into the internal memory of the machine from the bulk memory. Therefore, internal memory space need only be allocated for one such decision table.
  • Additional files in the internal memory are the digital input file, in which are placed the inputs received by the computer from the keyboard. Another file is the indication file, which is further illustrated in FIG. 6A.
  • FIG. 8 illustrates a track plan for a portion of the right-of-way which is to be controlled from the control office.
  • the vertical dotted lines in FIG. 8 denote the limits of the separate field stations.
  • FIG. 8 thus shows three field stations 40, 41 and 42.
  • Each of these field stations has a plurality of track signals and may have one or more track switches associated therewith. For each of these switches. signals. at various field stations. the computer must have available to it the current operational status of each device. and the indication file performs this function. i
  • FIG. 6A is divided into two halves. the left relating to the address and the right relating to the contents. As is well known. only the information in the right-hand portion is actually stored in the internal memory. Furthermore, the address in FIG. 6A, such as address 40. does not refer to an absolute address in the internal memory of the computer but merely refers to an address in the indication file in which is contained information related to field station 40. Each separate item corresponds to a bit of information. and is so stored. The particular bit address for each location is definitive of what the information represents. For instance. what is represented as bit 3 for field stations 40 and 41, (TK). is related to track occupancy. However. this same bit address for field station 42 relates to the normal position of switch number 2.
  • TK field stations 40 and 41
  • bit addresses for the particular items of information shown in FIG. 6A are merely examples. and the assignment of these bit locations and their representation can be varied in accordance with the operation of the particular computer shown. its internal memory, or the arrangement of information in the transmission system coupling the central office and the field stations.
  • the indication information received from the field stations over the communication lines is not transmitted to the indication file immediately. Instead. the indication input is transmitted to an indication input file which is structured similarly to the file shown in FIG. 6A.
  • One of the subroutines in the program compares the indication input file with the indication file and notes any indication changes; such changes are then stored in an indication change file.
  • the indication file is then updated so as to represent the latest information.
  • the indication change file which registers those indications that have most recently changed, forms a further input to the CTC subroutine which will be discussed in more detail later.
  • a further file. allocated in the internal memory of the machine. is a control file. shown in Table 1 above.
  • Table 1 A further detailed showing of the control file bit allocations is shown in FIG. 6B which has many similar characteristics to FIG. 6A.
  • Each address 40-42 refers to the field stations 40-42 shown for purposes of explanation in FIG. 8.
  • the contents of the control file do contain the location address as shown in FIG. 6B. This enables the communication system to transmit the address of the field station to which the controls are directed prior to transmission of the control signals themselves.
  • the control file stores controls which are to be transmitted to the respective field stations.
  • WN refers to a control to operate the track switch to its normal condition
  • WR refers to a control for the switch to its reverse condition
  • GN refers to a control to clear the signal for northbound traffic
  • GS refers to a control to clear the signal for southbound traffic, etc. Since location 42 is more complex than either location 40 or 41, we find that its control file makes provision for the control of two switches, W1 and W2, and also two signals, G1 and G2.
  • the remaining files in the internal memory to be discussed are the code start file, the flag file, and the answer back file.
  • the operator At the completion ofthe operators manipulation of the keyboard, in order to initiate the transmission of a control code to the field station, the operator must depress the code start button. However, prior to the actual transmission of the proper code, certain logical operations will have to take place. Therefore, in order to retain the indication that the operator has operated the code start button, a code start file is available to store the indication of a code start request along with the field station address to which the control is directed.
  • the flag file is another file for maintaining intermediate indications which are not yet fully processed. For instance, as will be explained below, prior to the transmission of a signal call, two logical operations have to take place. The first checks the propriety of the signal call against the conditions in the field related to traffic conditions. The second logical check is a track switch correspondence check, i.e. a check to determine, preparatory to the clearing of a wayside signal, that any associated track switch or switches are in the appropriate operated condition.
  • One of the functions, therefore, of the flag file is to store the intermediate signal requests, after their propriety has been approved, but prior to the time switch correspondence has been checked.
  • the switch request when a switch request is made, and approved, it is then stored in the control file for transmission to the field.
  • a signal request is made, and its propriety is approved by the decision table routines shown in FIGS. 70 and F, it is stored in the flag file. Only when the switch correspondence has been checked and determined is the signal request transferred from the flag file to the control file for transmission to the field.
  • the flag file can contain other information such as track blocking which is related to conditions in the field, but which is not received as an indication from the field station. Track blocking would be effected, for instance, if work was being done on a particular track section.
  • the answer back file is loaded under the particular conditions defined below.
  • a signal request cannot be translated into a signal call due to lack of switch correspondence, this is noted in the code start file by clearing the code start request and setting a delayed code start request.
  • the code start file is checked to see if a delayed code start request is pending. If it is, then the location number is inserted in the answer back file. This indicates that the flag file should be checked for a signal request for that location and switch correspondence should again be checked to see if the signal request can be translated from a signal request to a signal call for transmission to the field.
  • the CTC subroutine performs logical operations when the computer recognizes either a digital input, such as in input from the keyboard of FIG. 2, or indication change. Thus, the computer normally traverses the loop, checking for the various possible inputs.
  • the other mode of operation is for the field stations to transmit indications to the computer when, and only when, the status of one of its switches, signals, or track occupancy conditions changes.
  • the computer receives indications from a field station only when one of the indications at that station has changed.
  • the program which directs the computer would have to be slightly different for the different modes.
  • the communication program is arranged to sequentially interrogate each of the field stations while in the latter mode no such sub-routine is required.
  • the indications received are not all necessarily new information, some may be the same indications that are already stored in the computer from a previous indication transmission.
  • the indications received are applied to an indication input file where they are compared, on a bit-by-bit basis with the indica tions already contained in the indication file for that location.
  • the changed indication information is then stored in an indication change file for subsequent processing.
  • the instant invention is disclosed with a program operating under the first mode of operation, that is, the polling mode.
  • the CTC routine shown in FIG. is performed.
  • the program simply loops repeatedly through the routine.
  • the frequency at which the program is scanned is sufficiently high to permit at least one complete program scan between any two consecutive key actuations.
  • the communication routine is interlocked with the running of the CTC routine in the following manner: When an indication change is detected, the information is stored in the indication change file. This file is checked by the CTC routine of FIG. 5 on each program scan.
  • the indication change file is cleared so that a subsequentlydetected indication change can be inserted. If the communication system detects an indication change at a time when the indication change file is storing a previous indication change, the communication system ceases operating and waits until it can insert the lastfound indication change into the indication change file before proceeding to poll another field station.
  • FIG. 5 discloses a flow chart for the CTC sub-routine which handles the logical processes related to clearing signals, throwing switches, and keeping track of train positions such that an orderly routine is possible.
  • this drawing shows the CTC routine for interpreting keyboard inputs and indication changes and providing an output to the communications system to properly control the respective switches and signals at the various field stations.
  • This routine can be executed either periodically, i.e. for instance, every milliseconds, or it can be executed on a freerunning or repetitive basis. In the latter event, as soon as one scan through the routine is ended, a subsequent pass is initiated.
  • the first decision point 200 checks whether a transfer to or from bulk memory is in progress: if it is, the rest of the program is inhibited until the transfer is completed. Decision point 201 determines whether a push-button entry from the keyboard has been detected.
  • decision point 202 determines whether or not the decision table related to the selected group is in the internal memory; if not, the indicated transfer is made.
  • the next program function 203 is to find the decision table address which corresponds to the push-button input. The manner in which this function is accomplished will be described in relation to the decision tables which are found in FIG. 7.
  • the decision table processor at 204 takes over and performs the logical functions necessary to determine whether or not the selected controls are permissible.
  • the reentrant loop 205 provides a means whereby the program can perform this process for a number of pushbutton entries prior to entering the next step of the program.
  • function 206 clears the push-button entry flags and the location number inasmuch as they are no longer needed.
  • the entry flag is a reference to a bistable device associated with the keyboard which is set when the keyboard has input information to transmit to the computer. Once this input has been handled, as explained above, the flag is cleared.
  • the program next determines, at decision point 207, whether the code system is busy so as to provide the capability of transmitting controls. It will be recalled that the code system continually polls the field stations for transmission of indications to the central office. When the transmission of controls is taking place, the address associated with the field station which is to receive the controls is contained in a register. If no such communication is taking place, the register is cleared. The decision point 207 then merely requires the computer to check that particular register for the presence of an address. Subsequent to each indication communication with any field station, there is a period of time during which no communication takes place, and during this time the code system is not busy. If that is determined to be the case, the next decision point 208 determines if any code starts are wanted.
  • the last key is a code start key to indicate that he wants the controls transmitted and he is finished with that particular location.
  • the decision point 208 determines whether or not the code start button has been pushed. If it has, the next function 209 is to generate the location number associated with the field station to which the controls inputted at the keyboard are to be transmitted. The next decision point 210 determines whether the decision table associated with that location are in the internal memory of the machine. if it is not, the appropriate transfer is made and at function 211 the decision table takes over to determine switch correspondence. This is another decision table function and will be explained in relation to FIG. 7 which illustrates the details of the decision table.
  • switch correspondence is determined then, at function 212, the code system's busy indicator is set and the controls resident in the control tile for this location are subsequently outputted to the field.
  • decision point 213 in the program determines whether any indications have changed. if they have, decision points 214 determines whether the decision tables associated with the locations where the changed indications originated from are in the internal memory. If they are not, the appropriate transfer is made from the bulk memory.
  • the next function to be performed is to determine the address of the decision table associated with the changed indication, for processing.
  • the manner in which this is handled, as in the case of function 203, will be explained in relation to FIG. 7 with respect to the decision table and its operation.
  • the decision table processor at function 216, performs the necessary logical operations upon the changed indications.
  • the re-entrant loop 217 is provided to handle all of the changed indications at a particular location. When each of these has been handled and no further change indications are found, the program goes on to function 218 to determine if the code system is busy. This function is similar to the code system busy check at function 207.
  • the functions 211 and 222 are decision table processor functions which determine switch correspondence, i.e., the switch actually being in the position it is called for.
  • the answer back file is loaded when a switch indication change is detected with reference to a location having a delayed code start request pending.
  • the location number is generated for the relevant location at function 220. Any necessary decision table transfer is made at decision point 221.
  • Function 222 is a switch correspondence check which will cause a control code transmission at 223 if correspondence is detected. if no correspondence is detected, no changes are made in the various files. After the control code transmission or if no correspondence is detected the main scan is completed.
  • FIG. 5 Although the explanation of FIG. 5 is now complete, it is still necessary to explain how the decision table processor functions to determine on a logical basis the permissibility of a particular control inputted to the keyboard.
  • the particular decision table processors come into play at four separate locations in the flow diagram of FIG. 5.
  • Functions 203 and 204 in response to a keyboard input, first determine the address of the appropriate decision table input and then check the permissiblity of this control.
  • Functions 215 and 216 respond to an indication change, first to locate the address of the appropriate decision table and then process that information as necessary.
  • the functions performed by the processors at 211 and 222 are identical; in both cases the decision table determines whether the switches are in correspondence so as to enable the transmission of a signal control.
  • Function 203 in response to depression of the keyboard by the operator, the digital input file is filled in accordance with the particular keys depressed.
  • Function 203 merely counts the non-filled locations in the digital input file and determines which of the digital input file locations are filled in response to a key depression. The count at the time a non-zero location is detected determines which of the keys had been depressed. For the location 41 illustrated in FIG. 8 which has one switch and one signal, there are eight possible digital inputs.
  • the input determines the appropriate address, in the decision table, to process the initiation of that control.
  • the possible digital inputs are "maintainer-call on push-button, "maintainer-call off pushbutton”, “switch 1 normal push-button”, switch 1 reverse push-button", signal 1 stop push-button, signal 1 north push-button", signal 1 south pushbutton, and code start push-button.
  • the decision table incorporates a subroutine for each of these possi ble keyboard inputs as well as a subroutine for each of the possible indication change inputs and a further subroutine to check the switch correspondence. Each decision table is tailored for the particular field location it is related to.
  • location 41 has only one switch and one signal and therefore need only provide for the eight possible keyboard inputs relating to that switch or that signal
  • other locations with more switches and more signals would have a more extensive decision table based upon the track configuration for that location and the associated adjacent locations.
  • each of the subroutines comprises either decision points or the setting or resetting of various memory locations.
  • the decision points relate to the status of the control and indication files which reflect the controls which are to be sent and the status of the equipment in the field.
  • the particular bit location at which information is stored is determined by the particular field location. That is, a particular bit location for one field location may store a track occupancy indication whereas the same bit location for another field station may store a signal indication.
  • the bit locations in the control file are also dependent upon the particular field station to which they refer.
  • the decision table then incorporates not only the particular logical queries which are to be asked, but also indicates the location in memory at which the answer will be found. Because of the answer-back mode of operation, switch and signal call (controls) information will be located in the output file. Track switch requests relate to keyboard inputs and will be found in the digital input file. A wayside signal control inputted at the keyboard will be found in the digital input file and is termed a signal flag. The signal request, that is, a signal control which has been found permissible but not transmitted for lack of switch correspondence will be found in the software flag file.
  • the decision table operation makes use of four dif ferent operations.
  • the first is a branch which is capable of branching to either of two different locations, the first being an absolute location specified by the instruction, the second being to branch to a location a specified number of memory locations from the existing location.
  • the set instruction causes the machine to put a l at a particular bit location
  • the reset instruction causes the computer to clear or reset a particular bit location.
  • the fourth instruction is a test instruction which identifies a particular bit to be tested and carries with it two alternative subsequent instruction addresses. If the bit is set, one of these instruction addresses is effective, while if the bit is not set, the other instruction address is effective.
  • the decision table makes reference not only to the various files associated with the particular location to which the control will be directed, but also makes reference to the files associated with adjacent locations.
  • the first step in this subroutine 225 is to reset the call designated as the "maintainer-call-off". This is a reference to the control file and is merely designed to maintain logical consistency inasmuch as we will be setting the call designated as the maintainer-call-on" in step 226. This will result in, for instance, putting a l in bit location 11 and a 0 in bit location 12, in FIG. 6B.
  • the third step of this subroutine 227 is to reset the "maintainer-caIl-on push-button flag. This has reference to the digital input file, which initiated the subroutine. Thus, at this point, the control file has been set for a transmission to the field of a maintainer call on call as indicated by the keyboard input.
  • the subroutine is now complete and step 228 returns through re-entrant path 205 to search for further inputs from the keyboard.
  • FIG. 7B shows a subroutine if the maintainer-callof push-button had been depressed, including steps 229, 230, 231 and 232.
  • This subroutine performs the exact opposite of the subroutine shown in FIG. 7A, setting bit 12 and resetting bit 11 in the control file FIG. 6B for subsequent transmission to the field station.
  • FIGS. 7C and show the subroutine performed if a switch position push-button had been actuated.
  • the program checks to see whether the switch had been locked or blocked and, if not, sets the appropriate switch call in the control file and resets the push-button flag in the digital input tile and then returns to the main program, its function having been accomplished.
  • FIG. 7E shows the program subroutine for handling a north signal pushbutton request, that is, a request by the operator to clear the north signal.
  • the first decision point 233 is to check whether the track within that lo cation is occupied. If it is, then the signal will not be cleared, the subroutine jumps to point A in the program, resetting the signal north push-button flag at 247, and returns through 248 to the main program. However, if the track is not occupied, the program next determines at 234 whether a south signal had been requested for that location. If it had, the program again jumps to point A.
  • the program determines at 235 whether the switch is called normal and, if it is, then determines at 244 whether the main track between locations 40 and 41 is blocked. If it is blocked, the program then jumps to point A again. If it is not blocked, the next decision point 245 determines whether the traffic on the main track between locations 40 and 41 is north. If it is, the north signal request is set at 246 and the north signal push-button flag is reset at 247, and the program returns to the main through 248. If the machine has not determined that the traffic on the main track between locations 40 and 41 is north, then the next decision point 246 is to determine whether switch 40, i.e., the switch at location 40, is called reverse.
  • the next decision point 250 determines whether switch 40 is in the reverse position and, if it is, then the main track between locations 40 and 41 has its main traffic set north at 253 and its main traffic south reset at 242.
  • the program sets the north signal request for location 41 at 246, and proceeds through the program from point A. This portion has, in effect, determined that the switch at location 40 is in the reverse position, thus any traffic travelling south from location 39 would be shunted onto the siding and, therefore, with the switch at location 41 in the normal position, the signal at location 41 can be cleared north safely.
  • switch 40 determines at decision point 249 whether a south signal is requested at location 40. lf it is, then the north signal at location 41 cannot be safely cleared and the program jumps to point A resetting the north signal push-button flag at 247 and returning to the main program through 248. if switch 40 was not called reverse and there was no south signal request for signal 40, then the program determines at 250, if switch 40 is actually in the reverse position; if it is not, the program then determines at 251 if 40 south approach is indicating an approach. If it is, again, the north signal at location 41 cannot be safely cleared and thus the program returns to reset the north signal push-button flag at 247 and returns to the main program through 248.
  • the program resets at 252 the main track between locations 40 and 41 as south and sets at 253 that traffic as north, also sets the north signal request at 246, resets the north push-button flag at 247, and returns to the main program at 248.
  • switch 41 had not been called normal, the program determines at 236 if the switch was called reverse; if not, the program jumps to point A since the switch had been called neither reverse nor normal and the signal cannot be cleared. If the switch was called reverse, the next decision 237 point checks whether the traffic on the siding between locations 40 and 41 is north. If it is, the signal can be safely cleared as above. However, if it is not, the program determines at 238 ifthe switch at location 40 is called normal. If it is, the next decision point 240 determines if the switch 40 is actually normal; if it is, then the signal can be safely cleared. Therefore, the 40-41 siding traffic south is reset at 242, the 40-41 siding traffic north is set at 243 and the signal 41 north request is set as before. In effect, the program has determined that with the switch at location 41 in the reverse position and the switch at location 40in the normal position any southbound traffic coming from location 40 will travel on the main track and thus the north-bound traffic travelling on the siding track can be safely accommodated.
  • switch 40 was not called normal, the program then determines at 239 if the 40 south signal had been requested. lf it has, then the north signal cannot be cleared for the siding track and thus the program jumps to point A to reset the north push-button flag without setting the north signal request. if no south signal had been requested for location 40, the program next determines at 240 if the switch at location 40 is in a normal position. If it is not, the program must next determine at 241 if the 40 south approach is stuck, and if it is, it again jumps to point A in the program.
  • the siding between locations 40 and 41 has its traffic set north at 243 and its south traffic reset at 242.
  • the signal request is then set at 246, the push-button flag reset at 247, and the program returns to the main through 248 having completed its function.
  • the subroutine shown in FIG. 7F will determine the propriety of clearing the signal south with respect to the conditions at locations 41 and 42.
  • Location 42 is relevant inasmuch as that is the next-adjacent section in the route.
  • the first decision point 254 is to determine whether track section 41, adjacent the switch at location 41, is occupied. If it is, the program skips to point A to reset the south signal push-button flag 275 and return through 276. In effect, the program has determined it is not safe to clear the south signal at location 41 as the track adjacent the switch at location 41 is occupied.
  • the push-button flag in the digital input file has been reset at function 275 but nothing further is accomplished and therefore the signal will not be cleared.
  • decision point 255 determines whether the main track between locations 41 and 42 is blocked. If it is, again, the south signal at location 41 cannot be cleared, and therefore the program again skips to point A shown in FIG. 7F. If, however, the track is not blocked, decision point 256 determines if the main traffic between locations 41 and 42 is south.
  • decision point 260 determines whether the switch 42-2 is in the reverse position. This switch is identified in FIG. 8 as 42-2. If this switch is in the reverse position, then decision point 261 determines if the siding track at location 42, that is, track 42-2, is occupied. If it is, then the signal south cannot be cleared as, with switch 42-2 in the reverse position, the south traffic would be shunted onto the siding. Occupation of the siding therefore prohibits clearing the south signal under these conditions and the program skips to point A.
  • decision 262 determines if the switch 42-2 is called normal. If it is, then a decision point 263 determines if switch 42-1 is called reverse. Switch 42-1 is so designated in H6. 8.
  • switches at location 42 are controlled as two units. Only two situations can occur: either the location is treated as a siding as locations 40 and 41, or it is treated as a cross-over in which case, for north traffic, switch 42-1 would be reversed as would the next switch in the north direction, whereas the third switch in that direction would be normal.
  • switch 42-2 would be reverse, the next switch in the south direction would be reverse, and the next-following switch in the south direction would be normal. Therefore, identification of two switch positions is sufficient to describe the field conditions. Therefore. if decision point 263 determines that switch 42-1 is not called reverse it must determine, at decision point 264, if the 42-1 north signal is requested. If it is, then of course the south signal at location 41 cannot be cleared as a northbound train will be coming through on the main track. Therefore, the program skips to point A and refuses the south signal request. If, however, switch 42-1 is either called reverse or there is no 42-1 north signal request, then decision point 265 determines if switch 42-1 is reverse.
  • switch 42-2 had been called normal, then it is appropriate to approve the signal request and therefore function 272 resets 41-42 traffic as north, function 273 sets 41-42 traffic as south, function 274 sets 41 south signal request in the flag file, and function 275 resets the signal south push-button flag in the digital input file.
  • switch 42-1 was not in the reverse position, then it is necessary to determine if the 42-] north approach is stuck. If it is, then it would not be appropriate to clear the south signal at location 41 and the program skips to point A to refuse the request. However, if the 42-1 north approach is not stuck as determined at decision point 266, then it is appropriate to clear the south signal at location 41 and the program accomplishes this through functions 272 through 276.
  • decision point 267 determines if switch 42-1 was not called normal. If, however, decision point 267 determined that switch 42-1 was not called normal, then decision point 270 determines if the 42-1 north signal had been requested. If it had, the program skips to point A, refusing the request. Decision point 271 determines if the 42-1 north approach is stuck which would be another reason for refusing the south signal request at location 41. If it is, the program again skips to point A and refuses the request. If decision points 270 and 271 determine that the north signal at 42-1 had not been requested and the north approach at 42-1 was not stuck, then it is appropriate to clear the 41 south signal and this is again accomplished through functions 272 through 276.
  • the routine shown in FIG. 7F determines, based upon the conditions at location 41 and 42, if it is appropriate to clear the south signal as requested. If it is, the 41 south signal request is set in the flag file and the flag related to this signal south in the digital input file is reset. As has been explained above, however, the control file is not changed inasmuch as switch correspondence would have to be checked before clearing the signal in the field.
  • the address located at function 203 in FIG. 5 would refer the program to the subroutine shown in FIG. 7G.
  • This subroutine would ensure a signal stop call by resetting the north signal request 280, resetting the south signal request 281, resetting the north signal call 282, and resetting the south signal call 283.
  • the signal requests which are reset by 280 and 281 appear in the flag file and the calls reset at 282 and 283 appear in the control file.
  • the signal stop call in the control file is set, and the signal stop flag in the digital input file is reset at 285.
  • the subroutine is completed at 286 and exits to the main routine.
  • code start request The remaining possible digital or keyboard input is a code start request. This merely sets a code start request in a code start file with the address of the appropriate field location for which the code start is requested. Inasmuch as the code start is the last key depression for the transmission of a control for any one location, this key depression, after setting the code start request, clears all entry flags in the digital input file and also clears the location number initially inserted by the operator and, as shown in FIG. 5, the routine proceeds with function 207.
  • the decision points 290 through 293 determine whether the switches are in correspondence. If the switch is called normal and it is normal, decision points 290 and 291 are effective to step the program up to decision point 294. If the switch is called reverse and it is reverse, decision points 292 and 293 will again step the program up to decision point 294. If the switch is neither called normal nor called reverse then, regardless of the switch condition, no signal will be cleared as the program steps to point B shown in FIG. 7H. If the switches are not in correspondence, decision points 291 or 293 will determine this and step the program to point A shown in FIG. 7H.
  • decision point 294 determines if a north signal has been requested. This, as explained above, involves a reference to the flag file to determine if a signal has been requested and if such request is permissible as determined by the operation of the routine shown in FIG. 7E. It will be recalled that successful completion of this subroutine sets the north signal request at function 246. If such a north signal had been requested and the switches had been in correspondence, then the south signal call is reset and the north signal call is set by functions 298 and 299. Again, setting a signal call refers to setting a particular bit location in the control file for output to the field.
  • decision point 302 determines whether or not this is a delayed code start request.
  • a delayed code start request is merely a flag in the code start file which indicates a code start had been requested but the switches were not yet in correspondence. As such, every time the program goes through function 208, in FIG. 5, such a delayed code start would be detected and, at that time, if the switch was then in correspondence, the controls would be outputted. If the decision point 302 determines this is not a delayed code start request, then such a flag is set by function 303 to indicate that there is a signal request but that the switches are not yet in correspondence and therefore the signal call cannot be set.
  • functions 304, 305 and 306 reset the north signal call, reset the south signal call, and set the signal stop call, and then the program steps through functions 307 and 308 as before. If, however, a delayed code start request had already been set as determined by decision point 302, the program merely returns through function 308.
  • the switch correspondence routine illustrated in this figure determines whether the switches are in the proper position for the signal requests to be transmitted to the field.
  • the new indication is also transmitted to the indication file to keep that file up-to-date.
  • the track occupancy change causes the routine of FIG. 7.! to be performed.
  • the first function of this routine is to reset the change flag, function 310, which clears the indication change file.
  • Decision point 311 determines whether or not the track section is occupied: if it is not, the routine is completed and a return is made through function 316. However, if the change was from an unoccupied to an occupied section, then functions 312 through 315a are performed to reset the north and south signal requests, north and south signal calls, and set the signal stop call.
  • a CRT display unit for displaying the conditions of the system in the field.
  • standard panel displays can be operated as shown for instance in US. Pat. No. 2,967,232.
  • the CRT display enables a compact unit to display all the necessary information.
  • applicants system employs at least two different types of CRT displays. The first gives an overall general picture of the traffic layout without detailed information as to specific positions of switches and signals and train indications. When an operator desires to work with a particular field station, he first keys in the number of that location to cause the second CRT to display that location only.
  • This second display includes all the detail that is necessary for proper operator action in response to changing conditions in the field.
  • the display will indicate not only switch positions, signal conditions, but also track occupancy.
  • a standard CRT display is utilized which is capable of displaying a specific number of lines, each line consisting of a predetermined number of character positions.
  • the cyclic storage device associated with the CRT display stores the library of characters that is capable of being displayed and it also stores control codes to synchronize the CRT scan with the reading of the characters, one at a time, from the storage device. In this manner, the characters can readily be regenerated on the CRT screen as they are cyclically read from the display storage unit.
  • the particular CRT display used with applicants invention generates a track plan by the use of five different types of characters.
  • Each character is a straight line, the first being a line running up and to the left, the second a line running down and to the left, the third a line running up and to the right, the fourth a line running down and to the right and the fifth is a horizontal line.
  • any track plan can be produced by the use of these five characters.
  • any track plan can be written on a CRT screen.
  • Each of the locations has associated therewith a number identifying the type of track plan at that location.
  • the CRT will display, in the cyclically regenerated fashion, a track plan for that location.
  • the display must show a number of switches and there are four different types of switches, as shown in FIG. 9A.
  • the CRT is also capable of displaying a double instead of a single line.
  • the double line at 320 in FIG. 98 indicates that the switch illustrated was in the normal position
  • the double line 325 in FIG. 9C indicates the switch in

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Train Traffic Observation, Control, And Security (AREA)
US00291519A 1972-09-22 1972-09-22 Centralized traffic control system for railroads Expired - Lifetime US3836768A (en)

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Application Number Priority Date Filing Date Title
US00291519A US3836768A (en) 1972-09-22 1972-09-22 Centralized traffic control system for railroads
CA176,608A CA961969A (en) 1972-09-22 1973-07-17 Centralized traffic control system for railroads
ZA737224*A ZA737224B (en) 1972-09-22 1973-09-11 Centralised traffic control system for railroads
NL7312631A NL7312631A (es) 1972-09-22 1973-09-13
AR250182A AR200497A1 (es) 1972-09-22 1973-09-20 Aparato para control de trafico ferroviario
MX006107U MX3060E (es) 1972-09-22 1973-09-21 Mejoras a un sistema centralizado de control de transito de ferrocarriles
FR7334022A FR2208812B1 (es) 1972-09-22 1973-09-21
AU60558/73A AU486463B2 (en) 1972-09-22 1973-09-21 Centralized traffic control system for railroads
IT7329272A IT1001550B (it) 1972-09-22 1973-09-24 Sistema per il controllo centraliz zato di traffico ferroviario
GB4462773A GB1452328A (en) 1972-09-22 1973-09-24 Centralised traffic control system for railroads

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US00291519A US3836768A (en) 1972-09-22 1972-09-22 Centralized traffic control system for railroads

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US3836768A true US3836768A (en) 1974-09-17

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AR (1) AR200497A1 (es)
CA (1) CA961969A (es)
FR (1) FR2208812B1 (es)
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IT (1) IT1001550B (es)
MX (1) MX3060E (es)
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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3976272A (en) * 1974-11-18 1976-08-24 General Signal Corporation Control system for railroads
US4005392A (en) * 1974-08-02 1977-01-25 Toray Industries, Inc. Method and apparatus for detecting and recording abnormal conditions in the operation of spinning machines
US4015804A (en) * 1974-05-15 1977-04-05 International Standard Electric Corporation System for the demand-dependent control of guided vehicles
US4023753A (en) * 1974-11-22 1977-05-17 International Standard Electric Corporation Vehicle control system
US4041470A (en) * 1976-01-16 1977-08-09 Industrial Solid State Controls, Inc. Fault monitoring and reporting system for trains
US4092731A (en) * 1976-01-12 1978-05-30 Siemens Aktiengesellschaft Device for suppressing multiple registrations in a data store
US4122523A (en) * 1976-12-17 1978-10-24 General Signal Corporation Route conflict analysis system for control of railroads
US4247897A (en) * 1979-10-25 1981-01-27 Westinghouse Electric Corp. Train vehicle control microprocessor power reset
US4349196A (en) * 1980-02-08 1982-09-14 Smith Engineering Computer control toy track system
US5050823A (en) * 1989-11-30 1991-09-24 General Signal Corporation Radio-based railway switch control system
US5301906A (en) * 1992-06-17 1994-04-12 Union Switch & Signal Inc. Railroad interlocking control system having shared control of bottleneck areas
US5751569A (en) * 1996-03-15 1998-05-12 Safetran Systems Corporation Geographic train control
US6366930B1 (en) 1996-04-12 2002-04-02 Computer Associates Think, Inc. Intelligent data inventory & asset management systems method and apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1604492A (en) * 1978-05-30 1981-12-09 Westinghouse Brake & Signal Railway control systems

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2914662A (en) * 1955-09-26 1959-11-24 Gen Railway Signal Co Switch and signal control system for railroads
US2967232A (en) * 1957-03-20 1961-01-03 Gen Railway Signal Co Switch and signal control system for railroads
US3351907A (en) * 1963-05-03 1967-11-07 Warner Swasey Co Machine tool control system having means for ignoring invalid command signals
US3706073A (en) * 1965-11-12 1972-12-12 Mini En Electric Graphic display apparatus for direct analysis of electric power systems

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH349294A (de) * 1956-06-26 1960-10-15 Siemens Ag Elektrisches Eisenbahnstellwerk

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2914662A (en) * 1955-09-26 1959-11-24 Gen Railway Signal Co Switch and signal control system for railroads
US2967232A (en) * 1957-03-20 1961-01-03 Gen Railway Signal Co Switch and signal control system for railroads
US3351907A (en) * 1963-05-03 1967-11-07 Warner Swasey Co Machine tool control system having means for ignoring invalid command signals
US3706073A (en) * 1965-11-12 1972-12-12 Mini En Electric Graphic display apparatus for direct analysis of electric power systems

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4015804A (en) * 1974-05-15 1977-04-05 International Standard Electric Corporation System for the demand-dependent control of guided vehicles
US4005392A (en) * 1974-08-02 1977-01-25 Toray Industries, Inc. Method and apparatus for detecting and recording abnormal conditions in the operation of spinning machines
US3976272A (en) * 1974-11-18 1976-08-24 General Signal Corporation Control system for railroads
US4023753A (en) * 1974-11-22 1977-05-17 International Standard Electric Corporation Vehicle control system
US4092731A (en) * 1976-01-12 1978-05-30 Siemens Aktiengesellschaft Device for suppressing multiple registrations in a data store
US4041470A (en) * 1976-01-16 1977-08-09 Industrial Solid State Controls, Inc. Fault monitoring and reporting system for trains
US4122523A (en) * 1976-12-17 1978-10-24 General Signal Corporation Route conflict analysis system for control of railroads
US4247897A (en) * 1979-10-25 1981-01-27 Westinghouse Electric Corp. Train vehicle control microprocessor power reset
US4349196A (en) * 1980-02-08 1982-09-14 Smith Engineering Computer control toy track system
US5050823A (en) * 1989-11-30 1991-09-24 General Signal Corporation Radio-based railway switch control system
US5301906A (en) * 1992-06-17 1994-04-12 Union Switch & Signal Inc. Railroad interlocking control system having shared control of bottleneck areas
US5751569A (en) * 1996-03-15 1998-05-12 Safetran Systems Corporation Geographic train control
US6366930B1 (en) 1996-04-12 2002-04-02 Computer Associates Think, Inc. Intelligent data inventory & asset management systems method and apparatus
US6847982B2 (en) 1996-04-12 2005-01-25 Computer Associates Think, Inc. Intelligent data inventory and asset management system method and apparatus

Also Published As

Publication number Publication date
IT1001550B (it) 1976-04-30
GB1452328A (en) 1976-10-13
FR2208812A1 (es) 1974-06-28
CA961969A (en) 1975-01-28
NL7312631A (es) 1974-03-26
AR200497A1 (es) 1974-11-15
ZA737224B (en) 1974-08-28
FR2208812B1 (es) 1977-09-09
MX3060E (es) 1980-03-13
AU6055873A (en) 1975-03-27

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