Abstract:
This method includes, the railway network being subdivided into resources ( 1  to  5 ) whereof the state is driven by a ground controller ( 11 ), and each vehicle including an onboard controller ( 21 ) capable of communicating with the ground controller ( 11 ), of:
       planning, by a regulating unit ( 31 ), of a vehicle&#39;s mission;   transmitting said mission to the vehicle ( 20 ), the onboard controller of which:
           identifies a group of resources permitting the vehicle to continue its mission;   reserves the identified resources with the ground controllers;   once all of the resources are allocated, interlocks each resource in a required state;   verifies that each resource is reserved and is in the required state; and, when this verification is positive,   extends permission for the vehicle to move on the path corresponding to said group of resources.

Description:
[0001]    This claims the benefit of French Priority Application FR 10 52472, filed Apr. 1, 2010 and hereby incorporated by reference herein. 
         [0002]    The invention relates to the field of methods and systems for managing the circulation of a vehicle on a railway network. 
         [0003]    In this document, the term “vehicle” refers to any vehicle capable of moving on a railway network, such as a train, tramway, or subway, for example. 
       BACKGROUND 
       [0004]    A railway network is made up of various elementary objects, such as a track section with two end points, a track section with three end points or coupled switches, a signaling element, etc. 
         [0005]    At a given moment, each object is in an interlocking state assuming a specific value among a plurality of predefined possible values. 
         [0006]    To date, an interlocking logic is used to authorize a vehicle to move safely along a route of the railway. The interlocking logic is implemented by centralizing equipment, hereinafter called control unit, which controls the interlocking state of all of the elements composing the network. 
         [0007]    The interlocking logic uses a route table that shows, for each possible route, the values of the interlocking states of the objects composing said route that must be simultaneously verified to authorize the vehicle to move safely on the considered route. The definition of the route table is a compromise between flexibility and operating possibilities, technical feasibility and cost, while also considering deadlocks between movements. 
         [0008]    It is the control unit that, each moment, selects a route for a vehicle, modifies the interlocking state of the objects composing that route in compliance with the conditions mentioned in the route table, then, after verifying compliance with those conditions, authorizes the vehicle to move on the route. 
         [0009]    The control unit thus manages the movement of all of the vehicles circulating, at any given moment, on the railway network. 
         [0010]    The complexity of the route tables and the need for them to guarantee safe movements on the railway network that they describe, require that the route tables be generated manually, by experts. As a result, the creation of the route tables is a very costly step in terms of resources. 
         [0011]    Lastly, this architecture does not permit to update easily an existing railway network. For example, the replacement or addition of an object must be followed by the rewriting of the route table and its qualification before it can be integrated at the control unit. 
       SUMMARY OF THE INVENTION 
       [0012]    The invention aims to remedy the abovementioned problems. 
         [0013]    It is an object of the present invention to provide a method for managing the circulation of vehicles on a railway network, characterized in that, the network being subdivided into a plurality of resources, each resource having an allocation state, assuming the value “allocated” or “unallocated,” and having an interlocking state, assuming one value from among a plurality of predetermined values, one or several resources being driven by a ground controller equipped with wireless communication means, a regulating unit capable of planning all of the movements of the vehicles circulating on the network, and being connected to fixed base stations, on the ground, including wireless communication means, and each vehicle circulating on the network including an onboard controller equipped with wireless communication means permitting to communicate with the ground controllers and base stations connected to the regulating unit, the method comprising:
       planning, by the regulating unit, of a mission assigned to a vehicle;   transmission of said mission from the regulating unit to the controller onboard said vehicle;   identification, for a given time slot of the mission, by the controller onboard said vehicle, a group of resources that, on the condition each of said resources is allocated to said vehicle and is in a required interlocking state, would permit said vehicle to continue said mission, by using a path on the network corresponding to said group of identified resources;   reservation of the identified resources, consisting, by implementing a predetermined protocol, in the onboard controller requiring, from each of the ground controllers associated with the resources of the group of identified resources, the specific allocation of said resource to said vehicle;   then, once all of the resources of said group have been allocated to said vehicle, the interlocking of the resources, consisting, by implementing a predetermined protocol, of the onboard controller requiring, from each of the ground controllers associated with the resources of said group of allocated resources, the modification of the interlocking state of said resource in compliance with the required interlocking states;   verification, by the onboard controller of said vehicle, that each of the resources of the group of identified resources has been allocated to it and is in the required interlocking state; and, when the result of this verification is affirmative,   extension of the authorization, by the onboard controller, for the vehicle to move on the path of the network corresponding to the group of identified resources, allocated and correctly interlocked.       
 
         [0021]    According to specific embodiments, the method includes one or several of the following features, considered alone or according to all technically possible combinations:
       the controller onboard a vehicle sends the regulating unit, via the base stations, information on the position and/or group of identified resources, and the planning uses this information to update the various missions assigned to the different vehicles circulating on the railway network;   the method also includes a step for releasing a resource allocated to a vehicle, consisting in that, by carrying out a predetermined protocol, the controller onboard said vehicle requires, from the ground controller associated with said allocated resource, that said resource no longer be allocated to it;   the step for identifying a resource takes into account, in addition to said mission, descriptive information of the network and instantaneous position information on the vehicle;   the identification step includes a step for estimating a speed profile of the vehicle along a path of the network corresponding to a group of potential resources, preferably to determine the required time slot associated with each resource of a group of identified resources;   the step for allocating an identified resource includes:   emitting, by the controller onboard a vehicle, a request asking for the allocation of said identified resource sent to the ground controller associated with that resource;   emitting, by said ground controller, an allocation response delivering the allocation state and/or the interlocking state of the resource;   verifying, by the onboard controller, that there is no pending reservation and/or that no interlocking has interlocking states that are incompatible with the requested interlocking states;   the step for engaging an allocated resource includes:   emitting, by the controller onboard a vehicle, a request asking for the interlocking of said resource allocated to said vehicle, sent to the ground controller who is associated with said resource;   verifying, by said ground controller associated with said resource, whether the interlocking parameters for the current state of said resource are different from the requested interlocking parameters, and, in the affirmative, driving the resource according to the interlocking parameters; and,   emitting, by said ground controller, an interlocking response indicating the instantaneous interlocking state of the resource;   the step for releasing an allocated resource includes:   emitting, by the controller onboard the vehicle, a request asking for the release of said resource allocated to said vehicle, sent to the ground controller associated with said resource;   verifying, by said ground controller associated with said resource, whether the latter is allocated to the vehicle and, in the affirmative, no longer allocating said resource to the vehicle;   emitting, by said ground controller, a release response indicating that the resource is no longer allocated to said vehicle.       
 
         [0038]    The invention also relates to a controller onboard a vehicle circulating on a railway network, the network being subdivided into a plurality of resources that respectively have an allocation state, assuming the value “allocated” or “unallocated,” and an interlocking state, assuming one value from among a plurality of predetermined values, one or several resources of the network being associated with a single ground controller, each ground controller including: radio communication means; processing means permitting to allocate the associated resource and order a change in the interlocking state of the associated resource; driving means capable of determining the instantaneous interlocking state of the associated resource and, on command by the processing means, driving the associated resource according to the interlocking parameters of a received interlocking request, the onboard controller includes:
       radio communication means permitting to exchange messages between the onboard controller and the ground controllers;   identification means permitting to identify a group of resources that, on the condition each of said resources is allocated to said vehicle and is in a requested interlocking state, would permit said vehicle to continue an mission, by taking a path on the network corresponding to said group of identified resources, the mission being managed by a regulating unit including planning means so as to manage, on the network scale, the movements of the vehicles and to create an mission for each of them, the regulating unit being connected to fixed base stations, on the ground, including wireless communication means permitting communication with the onboard controller to transmit the mission assigned to said vehicle;   allocation and release means permitting, from a group of identified resources, to generate resource allocation requests intended to be sent to the ground controllers associated with said identified resources, and to process resource allocation responses coming from said ground controllers, and permitting, from a group of allocated resources, to generate resource interlocking requests, which include interlocking parameters, intended to be sent to the ground controllers associated with these allocated resources, and to process resource interlocking responses coming from said ground controllers;   verification means permitting to verify that all of the resources of a group of identified resources have been allocated to said vehicle and all of the resources of a group of allocated resources are in the requested interlocking state.       
 
         [0043]    According to other specific embodiments, the onboard controller includes one or several of the following features, considered alone or according to all technically possible combinations:
       the allocation and release means are capable, based on a plurality of allocated resources, of generating resource release requests intended to be sent to the ground controllers associated with said allocated resources, and to process resource release responses coming from said ground controllers;   the controller includes positioning means capable of delivering instantaneous position information for said vehicle;   the controller includes a database including a detailed description of the resources composing the railway network;   the controller includes means for estimating a speed profile of the vehicle on a group of potential resources;   the controller includes at least one list corresponding to a group of identified resources, the list including, for each resource in the group:   a resource identification field;   preferably, a field corresponding to a required allocation time slot for the resource;   a field corresponding to the “allocated” or “unallocated” allocation state of the resource to the vehicle;   a field defining the required interlocking state for the resource; and,   an interlocking field corresponding to a flag indicating that the resource is indeed in the required interlocking state.       
 
         [0054]    The invention also relates to a ground controller capable of being associated with at least one resource of a railway network, the network being subdivided into a plurality of resources that respectively have an allocation state, assuming the value “allocated” or “unallocated,” and an interlocking state, assuming one value from amongst a plurality of predetermined values, and, onboard a train circulating on the network, an onboard controller including radio communication means and allocation and release means making it possible to generate a resource allocation request intended to be sent to the ground controller, or a resource interlocking request, which includes interlocking parameters, intended to be sent to the ground controller. 
         [0055]    The ground controller includes:
       radio communication means capable of receiving an allocation or interlocking request for the resource associated with the ground controller;   processing means capable of allocating the associated resource in compliance with a received allocation request and ordering a modification of the interlocking state of the associated resource in compliance with a received interlocking request;   driving means capable of determining the instantaneous interlocking state of the associated resource and, upon command from the processing means, driving the associated resource according to the interlocking parameters of the interlocking request.       
 
         [0059]    According to specific embodiments, the ground controller includes one or several of the following features, considered alone or according to all technically possible combinations:
       the ground controller includes an allocation table including a stack of cells, each cell containing either the value NULL, or the identifier for a vehicle to which the resource is allocated;   the ground controller includes, for the or each resource associated with it, an interlocking state table including as many fields as there are parameters completely characterizing the interlocking state of said resource.       
 
         [0062]    The invention also relates to a system for managing the circulation of vehicles on a railway network, characterized in that, the network being subdivided into a plurality of resources, each resource having an allocation state assuming the value “allocated” or “unallocated” and having an interlocking state, assuming one value from amongst a plurality of predetermined values, the system includes:
       i)- a plurality of ground controllers, each ground controller being a ground controller as described above;   ii)- an onboard controller onboard a vehicle, the onboard controller being an onboard controller as described above; and,   iii)- a regulating unit including planning means so as to manage, on the network scale, the movements of the vehicles and to create a mission for each of them, the regulating unit being connected to fixed base stations, on the ground, including wireless communication means permitting communication with the controller onboard a vehicle to transmit the mission generated by the regulating unit assigned to said vehicle.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0066]    The invention and its advantages will be better understood upon reading the following description, provided solely as an example and done in reference to the appended drawings, in which: 
           [0067]      FIG. 1  is a schematic view of a portion of a railway network on which a train circulates; 
           [0068]      FIG. 2  is a schematic illustration of the elements composing the system for managing the circulation of trains according to the present invention, and flows of data between said elements; 
           [0069]      FIG. 3  is a schematic illustration of the method for managing the circulation of trains carried out by the system of  FIG. 2 ; 
           [0070]      FIG. 4  is a schematic illustration of the interlocking phase of said method; and 
           [0071]      FIG. 5  is a schematic illustration of the release phase of said method. 
       
    
    
     DETAILED DESCRIPTION 
       [0072]      FIG. 1  shows a portion of a railway network  10 . 
         [0073]    The network  10  is subdivided into a plurality of objects that are, according to the invention, considered to be resources.  FIG. 1 , for example, shows four sections of track with two end points, referenced  1  to  4 , and one section of track with three end points, or switches, referenced  5 . 
         [0074]    The network  10  includes other resources, such as signaling elements, for example, which are not described or shown for the sake of clarity of this description. 
         [0075]    Each resource of the network  10  can be associated with one or several members  13 . A member  13  can have a sensor function relative to the value of a characteristic parameter of the resource. A member  13  may have an actuating function permitting to modify the value of the corresponding characteristic parameter. 
         [0076]    The instantaneous interlocking state of a resource is the combination of the values of several parameters permitting to completely characterize the state of the resource. 
         [0077]    For example, in the case of a track section with two end points, a member including an induction sensor capable of detecting the presence of a train on the track section permit to determine the “occupied” or “unoccupied” occupation state of that track section. 
         [0078]    Also for example, in the case of a signaling element, a member permit to modify the display state of the signaling element. 
         [0079]    In  FIG. 1 , a single train  20  is shown. But, at a given moment, several trains can circulate simultaneously on the network  10 . 
         [0080]    To manage the circulation of the trains on the network  10 , a system for managing the circulation of the trains  15  is implemented. 
         [0081]    The system  15  includes:
       a plurality of ground controllers  11 , called ROC (Radio Object Controller) hereinafter, each resource of the network being associated with an ROC;   a plurality of onboard controllers  21 , called boardboard controllers, a single boardboard controller  21  being placed onboard each of the trains  20  circulating on the network; and   a regulating unit  31 , capable of planning the circulation of the various trains  20  circulating on the network  10 .       
 
         [0085]    The principle of the invention lies in the fact that the circulation of trains is, on a first scale, planned by the regulating unit, and, on a second scale, smaller than the first, managed, safely, by each train&#39;s boardboard controller. 
         [0086]    The planning by the regulating unit  31  of the circulation of a train includes the development of a mission sheet that is then sent to the train&#39;s boardboard controller. 
         [0087]    The management by the boardboard controller of a train&#39;s circulation is done by implementing a protocol permitting to allocate, interlock, then release the necessary resources directly with the ROC with which they are associated. In this architecture, it is the boardboard controller that authorizes the movement, safely, of the train on the path made up of the resources allocated to the train and permitting it to continue the mission assigned to it. 
         [0088]    In the embodiment described in detail here, a resource of the network  10  is associated with a single ROC. However, alternatively, several resources  10  can be associated with a single ROC. Each ROC and each resource are characterized by a unique identifier, on the network  10 . In the following, one ROC per network resource is considered. 
         [0089]    An ROC  11  is a computer including storage means, computation means, and input/output interfaces. 
         [0090]    The purpose of an ROC  11  is to control the resource with which it is associated. An ROC is a machine connected, via a wired line that may for example be bidirectional, to the or each member of the resource with which the ROC is associated, so as to drive that resource. An ROC  11  is arranged physically close to the resource it controls. 
         [0091]    For resources not having a member to drive, the ROC can be placed anywhere. 
         [0092]    Each ROC  11  includes:
       radio communication means  110 , permitting to establish a wireless connection with radio communication means  210  equipping the boardboard controller  21  of a train  20 , then exchanging, over the established wireless connection, messages according to a predetermined communication protocol. The communication means  110  transfer only the message that include the identifier of the ROC  11  to the processing means  118 ;   driving means  112  permitting to drive the or each member  13  of the associated resource;   an interlocking state table  114 , including as many fields as there are characteristic parameters permitting to define the instantaneous interlocking state of the associated resource, a field of the table  114  being updated by the driving means  112  as a function of the data indicated by the member corresponding to said characteristic parameter;   an allocation table  116 , including a stack of cells, each cell corresponding to a reservation or an interlocking of the resource and being able to assume the value “0” when the resource is “unallocated,” or the identifier of a train when the resource is “allocated” to that train; and   processing means  118 , capable of reading and writing in the allocation table  116 , reading in the interlocking state table  114 , controlling the driving means  112  and the radio communication means  110 .       
 
         [0098]    The means  110 ,  112  and  118  are preferably implemented in the form of computer programs whereof the instructions are stored in the storage means of the ROC  11  and are capable of being executed by the computation means of the ROC  11 . 
         [0099]    A boardboard controller  21  is a computer including storage means, computation means, and input/output interfaces. 
         [0100]    Each boardboard controller  21 , and as a result each train, is characterized by a unique identifier on the network  10 . 
         [0101]    Each boardboard controller  21  includes:
       radio communication means  210 , permitting to communicate simultaneously with several ROCs  11 . Preferably, these communication means also permit to establish a wireless connection with a base station  32  that is connected to the regulating unit  31 ;   positioning means  211 ;   identification means  212  permitting to identify a group of resources of the network  10  that would permit the train  20  to continue the performance of its mission;   resource allocation and release means  213 ;   verification means  214 ; and   estimating means  218 .       
 
         [0108]    Preferably, these different means are implemented in the form of computer programs executed by the board controller  21 . 
         [0109]    Moreover, the storage means of the board controller  21  include a database  215  for describing the railway network  10  and a mission file  216  transmitted by the regulating unit  31 . 
         [0110]    The database  215  includes information providing a detailed description of the resources composing the network  10 . The database  215  thus includes, for each resource of the network  10 , the interlocking state of the resource and geographical positioning data for the resource, such as the geographic positions of the end points thereof. 
         [0111]    The mission file  216  includes information corresponding to the journey the train  20  must make through the network  10 . For example, the mission file  216  includes the departure point of the train  20 , the arrival point of the train  20 , and an ideal path through the network  10 , i.e. all of the track sections that permit to connect the departure and arrival points, as well as characteristic points such as the commercial stops including information on the arrival and departure times the train  20  must respect. 
         [0112]    Preferably, the positioning means  211  permit to determine the position of the head and the rear portion of the train  20 . 
         [0113]    Within a track section, the position of the train  20  can be determined precisely by taking into account a measurement of the distance traveled from a reference point, e.g. a beacon of the state of the art. 
         [0114]    The identification means  212  generate a list of resources  217 , based on the information contained in the database describing the resources  215 , in the mission file  216 , and the instantaneous position of the train given by the positioning means  211 . 
         [0115]    A list  217  corresponds to a group of resources that, if they were allocated to the train and if they were located respectively in a required interlocking state, would permit the train to continue its mission along a path of the railway network  10  corresponding to that group of identified resources. 
         [0116]    Thus, a list  217  includes one row per resource from the group of identified resources and columns respectively corresponding to:
       an identification field indicating the resource identifier;   a field corresponding to a required time slot (in one simple embodiment, all of the resources from a group are to be allocated to the train in the same time slot);   a field corresponding to the “allocated” or “unallocated” allocation state of the resources to the train  20  (when the list  217  is generated, this field assumes the value NULL);   a field defining the required interlocking state for said resource; and   an interlocking field, corresponding to a flag indicating that the resource is indeed in the required interlocking state (when the list  217  is generated, this field assumes the value NULL).       
 
         [0122]    The estimating means  218  are capable of determining at least one speed profile on a path corresponding to a group of potential resources. From this speed profile, the means  218  are capable of estimating the passage moments of the train at particular points of said path. As a function of these passage moments, the identification means  212  determine the time slot in which each resource must be allocated to the train. The time slot thus required can take into account suitable safety margins, in particular the time necessary for the interlocking of the resource. 
         [0123]    When the verification means  214  are executed, they determine whether all of the resources of a list  217  have indeed been allocated to the train  20 , and whether all of the resources of a list  217  have the required interlocking state. 
         [0124]    When the resource allocation/release means  213  are executed, they perform the allocation, interlocking, and release phases of a group of identified resources, according to the protocol described below, by reading and writing in a list  217 , by generating the messages to be transmitted to the ROCs, and by processing the messages coming from the ROCs, via the radio communication means  210 . 
         [0125]    The system for managing the circulation of trains  15  also includes a regulating unit  31 . 
         [0126]    The regulating unit  31  includes planning means  310  permitting, on the network  10  scale, to develop the missions of the different trains circulating on said network  10 . A train&#39;s mission is developed taking into account any restrictions imposed on the movement of the train in question, by the missions of other trains circulating on the network  10 . 
         [0127]    Preferably, a first train&#39;s mission is regularly updated so as, for example, to take into account an event affecting the performance of another train&#39;s mission, and thereby modifying the restrictions taken into account during the initial development of the first train&#39;s mission. 
         [0128]    The regulating unit  31  is connected, for example through a TCP/IP network  33 , to a plurality of fixed base stations  32  on the ground. Preferably, the base stations are distributed along the tracks of the network  10  to offer continuous coverage of the network  10 . The base stations  32  include communication means  320  adapted to communicate with the board controller  21  of a train circulating on the network  10 . Preferably, these radio communication means  320  are compatible with the radio communication means  210  of the board controller  21 . 
         [0129]    It is then possible to exchange data between the board controller  21  of the train  20  and the regulating unit  31 : in downlink communication, the regulating unit communicates, aboard, the mission file  216  for the train  20 , which it has just developed or updated; in uplink communication, the board controller  21  communicates its instantaneous position to the regulating unit  31  so that it can update the missions of the train  20  and of other trains circulating on the network  10 . 
         [0130]    The method for managing the circulation of trains on the network  10  implemented by the system  15  will now be described. 
         [0131]    The file  216  describing the mission assigned to the train  20  is downloaded by the onboard controller  21  from the regulating unit  31  via a base station  32 . This may be the first base station  32  that the train  20  encounters when it starts along the network  10 , for example, at the train station or the exit of a maintenance garage or a depot, the mission file  216  then corresponding to the mission initially assigned to the train  20 . It can also be an intermediate base station  32  for downloading a mission file corresponding to an update of the initial mission file. 
         [0132]    At this moment, the train  20  is circulating on a path of the railway network  10  described by a list  217   a  stored by the board controller  21 . This current path includes, for example, track sections  1  and  2 . 
         [0133]    To continue its movement and the performance of its mission, the method according to the invention provides a phase for allocating a group of resources and a phase for engaging the resources of the group of allocated resources. 
         [0134]    The allocation phase shown in  FIG. 3  includes the identification, then reservation of a group of resources. 
         [0135]    In an identification step a, the identification means  212  are executed. They use the mission file  216 , the database  215  for describing the resources composing the network  10 , the instantaneous position of the train  20  delivered by the positioning means  211 , to generate a group of potential resources. The identification means  212  call the estimating means  218  to develop, from this group of potential resources and for an upcoming required time slot, a group of resources identified as permitting the train to continue its mission by taking the path corresponding to those resources, on the condition that the latter have been allocated to the train  20  and are placed in a required interlocking state. The identification means  212  then generate a list  217   b  corresponding to said group of identified resources. 
         [0136]    For example, in  FIG. 1 , for the train  20  to continue performing its mission, the means  212  generate a list  217   b  indicating that section  3  must be allocated to the train and must be in the interlocking state defined by the direction of circulation, and that section  5  must be allocated to the train and must be in the interlocking state defined by the direction of circulation and the positioning state. 
         [0137]    Once the list  217   b  has been placed in the storage means of the board controller  21 , the allocation/release means  213 , which monitor the storage means of the board controller  21 , are executed in a step b for developing resource allocation request messages. The means  213  develop as many requests as there are resources in the list  217   b . Each request includes the identifier of the requesting train and the identifier of the requested resource. 
         [0138]    In step c, the communication means  210  of the board controller  21 , controlled by the means  213 , emit radio signals corresponding to the different resource allocation requests. 
         [0139]    In step d, the communication means  110  of an ROC  11  pick up the different radio signals received and only transmit the messages including the identifier for said ROC (identifier identical to that of the resource with which the ROC is associated) to the processing means  118 . 
         [0140]    In step e, the processing means  118  read the allocation table  116  to determine whether the resource can be allocated to the requesting train. 
         [0141]    In step f, only when the table  116  indicates that the resource does not have a pending reservation, the processing means  118  allocate the resource to the requesting train, writing the identifier of the requesting train in the cell of the table  116 . 
         [0142]    Once a resource has been allocated, it cannot be allocated to another train, as long as the train to which it has been allocated does not interlock it. 
         [0143]    In step g, the processing means  118  of the ROC  11  develop an allocation response message. This response includes the identifier of the requesting train, the identifier of the requested resource, and the current state of reservations and interlockings. 
         [0144]    In step h, the communication means  110  emit a radio signal corresponding to this allocation response. 
         [0145]    In step j, the communication means  210  of the board controller  21  pick up and decode the various signals that reach them, and only transmit the messages that include the identifier of the train  20  to the allocation/release means  213 . 
         [0146]    In step k, when the allocation response indicates that the requested resource has indeed been allocated to the train, the means  213  update the allocation field corresponding to that resource in the list  217   b . The “allocated” value (+1) is written in the resource&#39;s allocation field. 
         [0147]    When the allocation response indicates that the requested resource cannot be allocated to the train, the means  213  update the allocation field for that resource by writing the “unallocated” value (0) there. 
         [0148]    At the end of a predetermined duration after step c of issuing resource allocation requests, the verification means  214  are executed by the onboard controller  21  to verify whether, yes or no, all of the resources from the list  217   b  have indeed been allocated to the train  20 . The verification means  214  then test the value of the allocation field for each of the resources in the list  215  (step 1). 
         [0149]    In case of positive verification, indicating that all of the requested resources from the list  217   b  have been allocated to the train  20 , that no reservation is pending, and/or that no interlocking has interlocking parameters that are incompatible with the requested interlocking parameters, the group of identified resources is considered a group of allocated resources (step m) and the method goes to the interlocking phase, which will be described below. 
         [0150]    In case of negative verification, i.e. when at least one of the resources from the list  217   b  is indicated as not being able to be allocated to the train  20 , the identification means  212  are executed again to generate another list  217   c  corresponding to another group of identified resources. The information relative to the resources from the list  217   b  that could not be allocated to the train  20  may be used by the means  212  during this new identification of a group of resources (step a). 
         [0151]    In case of incomplete verification, i.e. when several allocation fields from the list  217   b  still include the value NULL (and no “0” value) when the verification occurs, additional time is given and the verification means  214  are executed again several moments later. The allocation/release means  213  may be executed again to carry out steps b and c on the resources from the list  217   b  that are not yet allocated to the train  20 . If, during the following verification, some of the allocation fields from the list  217   b  remain at a NULL value, the verification is considered negative, and the board controller  21  tries to identify another group of resources (step a). 
         [0152]    The interlocking phase, illustrated in  FIG. 4 , unfolds as follows: 
         [0153]    When a group of resources is indicated as being allocated, the board controller  21  executes the allocation/release means  213  to develop a plurality of resource interlocking request messages (step b′). The means  213  develop as many requests as there are resources in the list  217   b . Each resource interlocking request includes the identifier for the requesting train, the identifier for the requested resource, and the interlocking parameters required for that resource. 
         [0154]    In step c′, the communication means  210  of the board controller  21 , controlled by the means  213 , emit radio signals corresponding to the various resource interlocking requests. 
         [0155]    In step d′, the communication means  110  of an ROC  11  pick up and decode the different radio signals received and only transmit the messages including the identifier of the ROC  11  to the processing means  118 . 
         [0156]    In step e′, after having verified that the identifier of the requesting train mentioned in the request corresponds to the identifier indicated in the allocation table  116 , the processing means  118  compare the requested interlocking parameters with the parameters of the instantaneous interlocking state of the resource indicated in the state table  114 . If the instantaneous state parameters of the resource are different from the requested interlocking parameters, the processing means  118  control the driving means  112  of the members of the resource in compliance with the requested interlocking parameters. 
         [0157]    In step f1′, the or each member  13  modifies the value of the corresponding characteristic parameter according to the required state. 
         [0158]    In step f2′, the members  13  transmit the current values of the parameter to the driving means  112 , which update the state table  114 . 
         [0159]    In step g′, the processing means  112  develop a resource interlocking response message. This response includes the identifier of the requesting train, the identifier for the requested resource, and the instantaneous interlocking state of the resource read in the state table  114 . 
         [0160]    In step h′, the communication means  110  of the ROC  11  emit a radio signal corresponding to the interlocking response. 
         [0161]    In step j′, the communication means  210  of the board controller  21  pick up and decode the various signals that reach them, and only transfer the messages that include the identifier of the train  20  to the allocation/release means  213 . 
         [0162]    When the interlocking response indicates that the requested resource has been placed according to the requested interlocking parameters, the means  213  write, in the interlocking field corresponding to that resource, the value “1” (value k′). 
         [0163]    At the end of a predetermined duration after the transmission of the resource interlocking requests, the verification means  214  are executed to verify whether all of the resources from the list  217   b  have indeed been interlocked according to the requested interlocking parameters. The means  214  then test the value of the interlocking field of each of the resources from the list  217   b  (step 1′). 
         [0164]    When all of the resources are correctly interlocked, the verification means  214  authorize the train  20  to advance and start out on the path of the network  10  corresponding to the group of resources from the list  217   b  (step m′). 
         [0165]    When some of the resources are not correctly interlocked, the means  214  do not deliver the movement authorization and steps b′ and c′ may be iterated, at least for the incorrectly interlocked resources. 
         [0166]    Once the onboard controller  21  sees that the rear portion of the train  20  has crossed one of the resources from the list  217   b , the identification means  212  are executed again to identify the next path of the network to be used (return to step a) and the allocation/release means  213  of the onboard controller  21  are executed to release this resource from the list  217   b . This release phase can also take place on a list of resources that are identified, but have not been able to be allocated to the train. This release phase is shown in  FIG. 5 . 
         [0167]    In step b″, from the list  217   b , the means  213  develop resource release request messages. Each request includes the identifier for the requesting train, and the identifier of the resource to be released. 
         [0168]    In step c″, the communication means  210  emit radio signals corresponding to these requests to release resources towards the various ROCs  11 . 
         [0169]    In step d″, the communication means  110  of an ROC  11  pick up the different received radio signals and only transmit the messages including said ROC&#39;s identifier to the processing means  118 . 
         [0170]    In step e″, the means  118  process the release request by reading, in the allocation table  116 , the identifier of the train to which the resource was allocated. If the read identifier corresponds to the identifier of the train indicated in the request, the means  118  modify the allocation state (step f″) of the resource by writing the value “unallocated” in the cell of the allocation table  116 . 
         [0171]    Only at that moment, the resource is released if no other reservation and/or no other interlocking has been recorded. 
         [0172]    In step g″, the processing means  112  develops a release response message. This response includes the identifier of the requesting train and the identifier of the requested resource. 
         [0173]    In step h″, the communication means  110  of the ROC  11  emit a radio signal corresponding to the release request. 
         [0174]    In step j″, the communication means  210  of the board controller  21  pick up and decode the different received signals, and only transfer the messages that include the identifier of the train  20  to the allocation/release means  213 . 
         [0175]    When the release response indicates that the resource has been released, the means  213  write the value “2” in the allocation field for that resource (step k″). 
         [0176]    At the end of a predetermined period after step c″ for issuing resource release requests, the verification means  214  are executed to verify whether, yes or no, all of the resources from the list  217   b  have indeed been released. The verification means  216  then test the value of the allocation field for each of the resources of the list  217   b  (step 1″). 
         [0177]    In this method, there is no overbooking of a resource. On the other hand a resource can be interlocked by several trains for identical requested interlocking parameters. 
         [0178]    Moreover, there is no connection between two resources on the network. Only the simultaneous allocation of two resources to the same train creates a “virtual” connection between those two resources. 
         [0179]    Alternatively, the identification means  212  simultaneously identify several groups of resources corresponding respectively to alternative paths on the network, which the train can follow to perform its mission. Once the verification means  214  detect that groups of resources have been entirely allocated to the train  20 , the other groups are released by executing the release means  213  on each of the other lists of resources. 
         [0180]    In still another alternative, the identification means  212  implement an initial step for questioning the ground controllers  11  preset in the environment of the train  20  to determine the allocation state of the associated resources. This embodiment can advantageously be done using a protocol for exchanging request and response messages similar to the protocols previously described. Prior knowledge of the allocation state of the potential resources facilitates the identification strictly speaking of a group of identified resources.