Patent Publication Number: US-10783785-B2

Title: Train presence detection apparatus

Description:
FIELD 
     The present invention relates to a train presence detection apparatus that determines whether a train is present in a designated section. 
     BACKGROUND 
     There is known a conventional technique for detecting whether a train is present in a specific section. In order to detect the presence of a train, it is necessary to specify a position where the train is present. As a technique for specifying a position where a train is present, there is disclosed a train that includes a train position specifying unit that specifies an absolute position of the train using wireless communication. (See, for example, Patent Literature 1). 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Patent Application Laid-open No. 2003-306146 
     SUMMARY 
     Technical Problem 
     In a line section formed in a loop, however, when a section is designated by two different end points, two designated sections are assumed. Consequently, even when an absolute position of a train is determined as in Patent Literature 1, it is impossible to determine whether the train is present in the designated section, which is a problem. 
     The present invention has been made to solve the above-described problem, and an object thereof is to provide a train presence detection apparatus capable of determining whether a train is present in a designated section designated in a line section formed in a loop. 
     Solution to Problem 
     In order to achieve the above object, a train presence detection apparatus according to an aspect of the present invention includes: an information acquisition unit to acquire position information on a first end point and a second end point located in a first line section formed in a loop and virtual block presence/absence information indicative of whether a virtual block indicating a specific position in the first line section is included in a designated section that is any of a first section and a second section in which the first end point and the second end point are located at both ends; a designated section determination unit to determine which of the first section and the second section is the designated section on a basis of the position information on the first end point and the second end point and the virtual block presence/absence information acquired by the information acquisition unit; and a presence determination unit to determine whether a train is present in the designated section determined by the designated section determination unit. 
     Advantageous Effects of Invention 
     The train presence detection apparatus according to an aspect of the present invention includes: an information acquisition unit to acquire position information on a first end point and a second end point located in a first line section formed in a loop and virtual block presence/absence information indicative of whether a virtual block indicating a specific position in the first line section is included in a designated section that is any of a first section and a second section in which the first end point and the second end point are located at both ends; a designated section determination unit to determine which of the first section and the second section is the designated section on a basis of the position information on the first end point and the second end point and the virtual block presence/absence information acquired by the information acquisition unit; and a presence determination unit to determine whether a train is present in the designated section determined by the designated section determination unit. Consequently, it is possible to determine the designated section designated in the first line section formed in a loop and to determine whether a train is present in the designated section. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating an example of a configuration of a train presence detection apparatus according to a first embodiment of the present invention. 
         FIG. 2  is a diagram illustrating examples of blocks and a virtual block set in a first line section formed in a loop. 
         FIG. 3  is a diagram illustrating a state in which the first line section formed in a loop illustrated in  FIG. 2  is one-dimensionally expressed. 
         FIG. 4  is a diagram illustrating an example of a case where the side that includes the virtual block is a designated section. 
         FIG. 5  is a diagram illustrating an example of a case where the side that does not include the virtual block is a designated section. 
         FIG. 6  is a diagram illustrating an example of a block sequence of the designated section illustrated in  FIG. 4 . 
         FIG. 7  is a diagram illustrating an example of a block sequence of the designated section illustrated in  FIG. 5 . 
         FIG. 8  is a flowchart illustrating an example of a flow of processes performed by the train presence detection apparatus according to the first embodiment of the present invention. 
         FIG. 9  is a diagram illustrating an example of a hardware configuration that implements the train presence detection apparatus illustrated in  FIG. 1 . 
         FIG. 10  is a block diagram illustrating another example of the configuration of the train presence detection apparatus according to the first embodiment of the present invention. 
         FIG. 11  is a block diagram illustrating an example of a configuration of a train presence detection apparatus according to a second embodiment of the present invention. 
         FIG. 12  is a diagram illustrating an example of a data configuration including virtual block presence/absence information stored in a sensor information database. 
         FIG. 13  is a block diagram illustrating another example of the configuration of the train presence detection apparatus according to the second embodiment of the present invention. 
         FIG. 14  is a block diagram illustrating still another example of the configuration of the train presence detection apparatus according to the second embodiment of the present invention. 
         FIG. 15  is a diagram illustrating an example of the virtual block in a case where a second line section formed in a loop is connected adjacent to the first line section. 
         FIG. 16  is a block diagram illustrating an example of a configuration of a train presence detection apparatus according to a third embodiment of the present invention. 
         FIG. 17  is a diagram illustrating examples of blocks set in the first line section formed in a loop and direction information. 
         FIG. 18  is a diagram illustrating an example of a case where the designated section is located in a clockwise direction from the first end point to the second end point. 
         FIG. 19  is a diagram illustrating an example of a case where the designated section is located in a counterclockwise direction from the first end point to the second end point. 
         FIG. 20  is a flowchart illustrating an example of a flow of processes performed by the train presence detection apparatus according to the third embodiment of the present invention. 
         FIG. 21  is a block diagram illustrating an example of a configuration of a train presence detection apparatus according to a fourth embodiment of the present invention. 
         FIG. 22  is a diagram illustrating an example of a data configuration including direction information stored in the sensor information database. 
         FIG. 23  is a block diagram illustrating another example of the configuration of the train presence detection apparatus according to the fourth embodiment of the present invention. 
         FIG. 24  is a block diagram illustrating an example of a configuration of a train presence detection apparatus according to a fifth embodiment of the present invention. 
         FIG. 25  is a diagram illustrating an example of a configuration in which a third line section, through which a train can enter the first line section, is connected to the first line section. 
         FIG. 26  is a flowchart illustrating an example of a flow of processes performed by the train presence detection apparatus according to the fifth embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of a train presence detection apparatus according to the present invention will be described with reference to the drawings. 
     First Embodiment 
       FIG. 1  is a block diagram illustrating an example of a configuration of a train presence detection apparatus  1  according to a first embodiment. As illustrated in  FIG. 1 , the train presence detection apparatus  1  includes an input reception unit  2  that receives input of information; an information acquisition unit  3  that acquires various types of information; a designated section determination unit  4  that determines, on the basis of the information acquired by the information acquisition unit  3 , a designated section designated in a loop line section L 1  that is a first line section formed in a loop; a presence determination unit  5  that determines whether a train  20  is present in the designated section determined by the designated section determination unit  4 ; an approach determination unit  6  that determines whether the train  20  is approaching the designated section; a train control unit  7  that generates train control information for controlling the train  20  traveling in the loop line section L 1 ; and a track database  8  that stores route information that is information on a route on which the train  20  travels. In the present embodiment, an example will be described in which the train presence detection apparatus  1  is configured from a ground apparatus  10  that performs wireless communication with the train  20  via a ground wireless apparatus  9 . However, the train presence detection apparatus  1  of the present invention is not limited thereto, and may be configured to include an on-board apparatus  21  included in the train  20  as described later or the ground apparatus  10  and the on-board apparatus  21 . 
     The input reception unit  2  is used for receiving information input by an operator, for example. The input reception unit  2  includes, for example, a mouse, a keyboard, and a touch panel, and the operator inputs various types of information, operation commands, and the like. In order to designate a designated section in the loop line section L 1 , the input reception unit  2  receives input of position information on a first end point P 1  and a second end point P 2  located at both ends of the designated section and virtual block presence/absence information that indicates whether a virtual block VB indicating a specific position in the loop line section L 1  is included in the designated section. The input reception unit  2  outputs, to the information acquisition unit  3 , the received position information on the first end point P 1  and the second end point P 2  and the received virtual block presence/absence information. The designated section is, for example, a temporary speed limit section that is a section in which the train  20  needs to be decelerated to a temporary speed limit or a train protection section that is a section in which entry of the train  20  needs to be prohibited. 
       FIG. 2  is a diagram illustrating examples of blocks and a virtual block set in the first line section formed in a loop.  FIG. 3  is a diagram illustrating a state in which the first line section formed in a loop illustrated in  FIG. 2  is one-dimensionally expressed.  FIG. 4  is a diagram illustrating an example of a case where the side that includes the virtual block is a designated section.  FIGS. 2 and 3  illustrate a virtual block VB and multiple divided blocks [B 1001 ] to [B 1010 ] that are set in the loop line section L 1 . Information on such blocks [B 1001 ] to [B 1010 ] and the virtual block VB is stored, for example, in the track database  8 . In  FIG. 2 , numerals in balloons attached to reference points of the blocks [B 1001 ] to [B 1010 ] on the loop line section L 1  indicate kilometrage at the reference points of the blocks [B 1001 ] to [B 1010 ]. The position information on the first end point P 1  and the second end point P 2  is expressed, for example, by a block number and an intra-block position. For example, as illustrated in  FIG. 4 , the position information (kilometrage) on the first end point P 1  is expressed as 240 obtained by adding 40 that is a coordinate value at the intra-block position in the block [B 1003 ] to 200 that is kilometrage (coordinate value) at a reference point of the block [B 1003 ]. The position information (kilometrage) on the second end point P 2  is expressed as 800 obtained by adding 0 that is a coordinate value at the intra-block position in the block [B 1009 ] to 800 that is a coordinate value at a reference point of the block [B 1009 ].  FIG. 2  illustrates an example in which a coordinate value is set such that it decreases when the train  20  travels in a clockwise direction and increases when the train  20  travels in a counterclockwise direction. Since all the blocks [B 1001 ] to [B 1010 ] have a length of “100” in  FIG. 2 , the block [B 1001 ] has a coordinate value of 0 to 100, the block [B 1002 ] has a coordinate value of 100 to 200, the block [B 1003 ] has a coordinate value of 200 to 300, the block [B 1004 ] has a coordinate value of 300 to 400, the block [B 1005 ] has a coordinate value of 400 to 500, the block [B 1006 ] has a coordinate value of 500 to 600, the block [B 1007 ] has a coordinate value of 600 to 700, the block [B 1008 ] has a coordinate value of 700 to 800, the block [B 1009 ] has a coordinate value of 800 to 900, and the block [B 1010 ] has a coordinate value of 900 to 0 in the illustrated example. The coordinate of a terminating end of each block and the coordinate of a starting end of a block adjacent thereto indicate the same position. The way of setting blocks is not limited to the above. Although a coordinate value is set such that it decreases when the train  20  travels in the clockwise direction and increases when the train  20  travels in the counterclockwise direction in  FIG. 2 , there is no limitation thereto. The coordinate value may be set such that it increases when the train  20  travels in the clockwise direction and decreases when the train  20  travels in the counterclockwise direction. 
     The virtual block VB is a point that indicates a specific position in the loop line section L 1 . The virtual block VB indicates, for example, a predetermined fixed position in the loop line section L 1 , and in the present embodiment, as illustrated in  FIG. 2 , the virtual block VB is set at a position of a kilometrage of 0, which is a connection point between a start point and an end point of the loop line section L 1 . The position where the virtual block VB is set is not limited to the connection point between the start point and the end point of the loop line section L 1 , and the virtual block VB may be set at any position in the loop line section L 1  as long as position information is known in advance. In addition, the position information on the first end point P 1  and the second end point P 2  is not designated as a coordinate value of the virtual block VB. That is, the first end point P 1 , the second end point P 2 , and the virtual block VB are all set to have different coordinate values. When it is desired to designate either the first end point P 1  or the second end point P 2  as the coordinate value of the virtual block VB, the position information on the first end point P 1  or the second end point P 2  may be designated such that the virtual block VB is included in the designated section with allowance. The virtual block presence/absence information is information that indicates whether a virtual block is included in a designated section that is any of a first section A 1  and a second section A 2  illustrated in  FIG. 2  in which the first end point P 1  and the second end point P 2  are located at both ends. 
     As illustrated in  FIG. 1 , the information acquisition unit  3  acquires the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information that are input information received by the input reception unit  2 . The information acquisition unit  3  outputs the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information thus acquired to the designated section determination unit  4 . In addition, the information acquisition unit  3  acquires, from the track database  8 , route information that indicates a route on which the train  20  travels. The information acquisition unit  3  outputs, for example, the acquired route information to the approach determination unit  6 . The route information includes information on a traveling section of the train  20  and information on a traveling direction (clockwise or counterclockwise direction) of the train  20 , and is expressed, for example, by a block number. A route R 1011 , which is an example of the route information illustrated in  FIG. 3 , represents route information in accordance with which the train  20  travels the blocks [B 1001 ], [B 1002 ], and [B 1003 ] in this order (counterclockwise direction). Although the present embodiment indicates an example in which the track database  8  is provided in the ground apparatus  10 , the track database  8  may be provided outside the ground apparatus  10 . In addition, the information acquisition unit  3  acquires presence position information on the train  20  from the train  20  via an on-board wireless apparatus  22  and the ground wireless apparatus  9 . The information acquisition unit  3  outputs the acquired presence position information on the train  20  to the presence determination unit  5 . Although only one train  20  is illustrated in  FIG. 1 , actually, there are a plurality of trains  20  that travel in the loop line section L 1 , and the information acquisition unit  3  acquires the presence position information from each train  20  as well as a train ID for identifying each train  20 . Although the present embodiment indicates the example in which the information acquisition unit  3  acquires information from the train  20  via the ground wireless apparatus  9 , there is no limitation thereto, and the information acquisition unit  3  may be configured to acquire information via a wired connection. 
     The designated section determination unit  4  determines which of the first section A 1  and the second section A 2  is the designated section on the basis of the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information acquired by the information acquisition unit  3 . Only with the position information on the first end point P 1  and the second end point P 2  indicating the positions of both ends of the designated section, it is impossible to determine which of the first section A 1  and the second section A 2  is the designated section as illustrated in  FIG. 2 . Therefore, the virtual block presence/absence information that is information indicating whether the virtual block VB is included in the designated section is used in the train presence detection apparatus  1  according to the present invention. Thus, when information indicating that the designated section includes the virtual block VB is acquired as the virtual block presence/absence information, for example, the designated section determination unit  4  determines, as illustrated in  FIG. 4 , that the first section A 1  that is the side that includes the virtual block VB is the designated section.  FIG. 5  is a diagram illustrating an example of a case where the side that does not include the virtual block is the designated section. When information indicating that the designated section does not include the virtual block VB is acquired as the virtual block presence/absence information, the designated section determination unit  4  determines, as illustrated in  FIG. 5 , that the second section A 2  that is the side that does not include the virtual block VB is the designated section.  FIG. 6  is a diagram illustrating an example of a block sequence of the designated section illustrated in  FIG. 4 .  FIG. 7  is a diagram illustrating an example of a block sequence of the designated section illustrated in  FIG. 5 . When the designated section is determined, the designated section determination unit  4  generates a block sequence of a section (designated section) between two points that are the first end point P 1  and the second end point P 2 , as illustrated in each of  FIGS. 6 and 7 . 
     The presence determination unit  5  determines whether the train  20  traveling in the loop line section L 1  is present in the designated section determined by the designated section determination unit  4 . The presence determination unit  5  determines whether the train  20  is present in the designated section on the basis of the presence position information on the train  20  acquired by the information acquisition unit  3  and the information on the designated section determined by the designated section determination unit  4 . 
     The presence position information is information on the position of the train  20  in the loop line section L 1 , and is expressed, for example, by a block number and an intra-block position similarly to the position information on the first end point P 1  and the second end point P 2 . Although not illustrated in detail, for example, when the train  20  passes a ground coil installed at a starting end of each of the blocks [B 1001 ] to [B 1010 ] set in the loop line section L 1 , a pickup coil in the train  20  detects ground coil information. The ground coil information is received as pickup coil information in the on-board apparatus  21  included in the train  20 . The on-board apparatus  21  detects the position of the ground coil by the pickup coil information, uses an absolute position of the ground coil as a reference position, and calculates a travel distance from the reference position, for example, on the basis of speed information detected by a rate generator attached to an axle, thereby obtaining an intra-block position that is a position of the train  20  in a block. Thus, the on-board apparatus  21  can obtain the presence position information on the train  20  to which the on-board apparatus  21  belongs. The ground coil is not limited to being installed at the starting end of each of the blocks [B 1001 ] to [B 1010 ]. There may be cases where the ground coil is installed at a fixed-distance interval, where one ground coil is installed every multiple blocks, or where the ground coil is installed at a position other than the starting end of each of the blocks. The method for obtaining the presence position information on the train  20  is not limited to the above, and a conventionally known method can be used. 
     The on-board apparatus  21  adds the presence position information on the train  20  and the information on the traveling direction of the train  20  to information on a train ID for identifying the train  20  to which the on-board apparatus  21  belongs, for example, and outputs the above pieces of information to the on-board wireless apparatus  22 . The on-board wireless apparatus  22  transmits information including the presence position information on the train  20  received from the on-board apparatus  21  to the ground wireless apparatus  9 . The ground wireless apparatus  9  transmits information including the presence position information on the train  20  received from the on-board wireless apparatus  22  to the information acquisition unit  3  of the train presence detection apparatus  1  (ground apparatus  10 ). Thus, the information acquisition unit  3  acquires the presence position information from the train  20  via the ground wireless apparatus  9 . In the train  20 , the pickup coil that detects ground coil information is provided on both a lead vehicle and a tail vehicle, and thereby a front end position and a rear end position of the train  20  can be obtained. In addition, one of the front end position and the rear end position of the train  20  may be obtained by providing the pickup coil to one of the lead and tail vehicles of the train  20 , and the other of the front end position and the rear end position may be obtained by performing calculation using the train length. 
     For example, when the designated section determination unit  4  determines that the first section A 1  illustrated in  FIG. 2  is the designated section as illustrated in  FIG. 4 , the presence determination unit  5  determines whether the presence position (kilometrage) of the train  20  is included in the block sequence of the designated section (first section A 1 ), thereby determining whether the train  20  is present in the designated section. More specifically, the presence determination unit  5  determines whether kilometrage at either the front end position or the rear end position of the train  20  is less than or equal to kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to kilometrage (800) at the position of the second end point P 2  thereof, and when the kilometrage at either the front end position or the rear end position of the train  20  is determined to be less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof, the presence determination unit  5  determines that the train  20  is present in the designated section A 1 . 
     When the presence determination unit  5  determines that the train  20  is not present in the designated section, the approach determination unit  6  determines whether the distance from the train  20  to a starting end point is within a specific range, the starting end point being any of the first end point P 1  and the second end point P 2  that is closer to the train  20  in the traveling direction of the train  20 . Even in a case where the train  20  is not present in the designated section, when the designated section is the temporary speed limit section or the train protection section, there may be a case where it is necessary to reduce the traveling speed of the train  20  or to stop the train  20  when the train  20  approaches the designated section. Therefore, the approach determination unit  6  determines whether the train  20  is approaching the designated section. 
     For example, on the basis of the route information that indicates a route on which the train  20  travels, the approach determination unit  6  determines whether the distance from the train  20  to the starting end point is within a specific range, the starting end point being an end point of the designated section closer to the train  20  in the traveling direction. The approach determination unit  6  determines whether the starting end point of the designated section is included in the route on which the train  20  travels, the route being indicated by the route information, and when the starting end point of the designated section is included in the route on which the train  20  travels, the approach determination unit  6  determines that the train  20  is approaching the designated section. For example, as illustrated in  FIG. 4 , a train  20   b  is not present in the designated section A 1 . However, the train  20   b  is present in the block [B 1004 ], and the route information in accordance with which the train  20   b  travels is a route R 1018  and indicates a travel route from kilometrage (500) at a position of a terminating end of the block [B 1005 ] to kilometrage (200) at a position of a starting end of the block [B 1003 ] in the clockwise direction. Therefore, the approach determination unit  6  determines that the route R 1018  of the train  20   b  includes the first end point P 1  (kilometrage is 240) that is a starting end point of the designated section A 1 , and the train  20   b  is determined to be approaching the designated section. On the other hand, a train  20   c  is present in the block [B 1006 ], and the route information in accordance with which the train  20   c  travels is a route R 1017  and indicates a travel route from kilometrage (700) at a position of a terminating end of the block [B 1007 ] to kilometrage (400) at a position of a starting end of the block [B 1005 ] in the clockwise direction, as illustrated in  FIG. 3 . Therefore, the approach determination unit  6  determines that the route R 1017  of the train  20   c  does not include the first end point P 1  (kilometrage is 240) that is the starting end point of the designated section A 1 , and the train  20   c  is determined to be not approaching the designated section. The method for determining by the approach determination unit  6  whether the train  20  is approaching the designated section is not limited to a method based on the route information. For example, whether the train  20  is approaching the designated section may be determined by calculating the distance from the front end position of the train  20  to the starting end point of the designated section and determining whether the distance falls in a specific distance range set depending on the types of the designated section or the like. 
     The train control unit  7  generates train control information for controlling the train  20 . The train control information generated by the train control unit  7  is transmitted to the train  20  via the ground wireless apparatus  9 . In the train  20 , the on-board wireless apparatus  22  receives the train control information sent from the ground wireless apparatus  9 , and the on-board wireless apparatus  22  outputs the train control information to the on-board apparatus  21 . The on-board apparatus  21  performs control of travel and the like of the train  20  on the basis of the train control information received from the on-board wireless apparatus  22 . The train control information includes, for example, temporary speed control information for decelerating the train  20  to a temporary speed limit and train protection information indicating an entry prohibited section for the train  20 . The train control unit  7  generates train control information on the basis of the determination result of the presence determination unit  5  or the approach determination unit  6 . When it is determined by the presence determination unit  5  that the train  20  is present in the designated section or it is determined by the approach determination unit  6  that the train  20  is approaching the designated section, the train control unit  7  generates train control information for performing travel control such that the traveling speed of the train  20  is reduced to a specific speed or lower or train control information for stopping the train  20 , for example, depending on the types of the designated section. 
       FIG. 8  is a flowchart illustrating an example of a flow of processes performed by the train presence detection apparatus  1  according to the first embodiment of the present invention. Hereinafter, the flow of processes performed by the train presence detection apparatus  1  will be described with reference to the flowchart of  FIG. 8 . In the train presence detection apparatus  1  according to the present embodiment, as illustrated in  FIG. 8 , the information acquisition unit  3  first determines whether the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information, which are input information received by the input reception unit  2 , have been acquired (S 101 ). When the information acquisition unit  3  determines that the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information have not been acquired (S 101 : No), the information acquisition unit  3  again determines whether the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information have been acquired (S 101 ). That is, the information acquisition unit  3  repeats the determination of S 101  until the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information are acquired. When the information acquisition unit  3  determines that the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information have been acquired (S 101 : Yes), the information acquisition unit  3  outputs the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information thus acquired to the designated section determination unit  4 . 
     On the basis of the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information received from the information acquisition unit  3 , the designated section determination unit  4  determines which of the first section A 1  and the second section A 2  in which the first end point P 1  and the second end point P 2  are located at both ends is the designated section, and generates a block sequence indicating the section (designated section) between two points that are the first end point P 1  and the second end point P 2  (S 102 ). 
     The presence determination unit  5  determines whether the front end position or the rear end position of the train  20  is included in the block sequence of the designated section on the basis of the presence position information on the train  20  acquired by the information acquisition unit  3  and information on the designated section determined by the designated section determination unit  4  (S 103 ). For example, as illustrated in  FIG. 4 , when the designated section determination unit  4  determines that the first section A 1  illustrated in  FIG. 2  is the designated section, the presence determination unit  5  first determines whether kilometrage at the front end position of the train  20  is less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof. When the presence determination unit  5  determines that the kilometrage at the front end position of the train  20  is less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof (S 103 : Yes), the presence determination unit  5  determines that the train  20  is present in the designated section A 1  (S 104 ), and ends the presence detection process performed by the train presence detection apparatus  1 . That is, as illustrated in  FIG. 4 , a train  20   a  present in the block [B 1002 ] whose kilometrage is 100 to 200 is determined by the presence determination unit  5  to be present in the designated section A 1 . 
     On the other hand, when the presence determination unit  5  determines that the kilometrage at the front end position of the train  20  is not less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  and not greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof, the presence determination unit  5  next determines whether the kilometrage at the rear end position of the train  20  is less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof. When the presence determination unit  5  determines that the kilometrage at the rear end position of the train  20  is less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof (S 103 : Yes), the presence determination unit  5  determines that the train  20  is present in the designated section (S 104 ), and ends the presence detection process performed by the train presence detection apparatus  1 . However, when the presence determination unit  5  determines that the kilometrage at the rear end position of the train  20  is not less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  and not greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof, that is, when the presence determination unit  5  determines that neither the kilometrage at the front end position of the train  20  nor that at the rear end position thereof is included in the designated section A 1  (S 103 : No), the presence determination unit  5  determines that the train  20  is not present in the designated section (S 105 ). That is, as illustrated in  FIG. 4 , the train  20   b  present in the block [B 1004 ] whose kilometrage is 300 to 400 and the train  20   c  present in the block [B 1006 ] whose kilometrage is 500 to 600 are determined by the presence determination unit  5  not to be present in the designated section A 1 . 
     When the presence determination unit  5  determines that the train  20  is not present in the designated section (S 105 ), then the approach determination unit  6  determines whether the starting end point that is an end point of the designated section closer to the train  20  in the traveling direction of the train  20  is included in the route on which the train  20  travels, the route being indicated by the route information (S 106 ). For example, when the train  20   b  is present in the block [B 1004 ] as in illustrated in  FIG. 4 , the route information in accordance with which the train  20   b  travels is the route R 1018  and indicates a travel route from the kilometrage (500) at the position of the terminating end of the block [B 1005 ] to the kilometrage (200) at the position of the starting end of the block [B 1003 ] in the clockwise direction, and therefore, the approach determination unit  6  determines that the first end point P 1  (kilometrage is 240) that is the starting end point of the designated section A 1  is included in the route R 1018  of the train  20   b  (S 106 : Yes). Then, the approach determination unit  6  determines that the train  20   b  is approaching the designated section A 1  (S 107 ), and ends the presence detection process performed by the train presence detection apparatus  1 . 
     On the other hand, for example, when the train  20   c  is present in the block [B 1006 ] as in illustrated in  FIG. 4 , the route information in accordance with which the train  20   c  travels is the route R 1017  and indicates a travel route from the kilometrage (700) at the position of the terminating end of the block [B 1007 ] to the kilometrage (400) at the position of the starting end of the block [B 1005 ] in the clockwise direction as illustrated in  FIG. 3 , and therefore, the approach determination unit  6  determines that the first end point P 1  (kilometrage is 240) that is the starting end point of the designated section A 1  is not included in the route R 1017  of the train  20   c  (S 106 : No). Then, the approach determination unit  6  determines that the train  20   c  is not approaching the designated section A 1  (S 108 ), and ends the presence detection process performed by the train presence detection apparatus  1 . 
     In the present embodiment described above, the train presence detection apparatus  1  (ground apparatus  10 ) includes a processor, a storage circuit, a receiver, and a transmitter, and each operation can be implemented by software.  FIG. 9  is a diagram illustrating an example of a hardware configuration that implements the train presence detection apparatus  1  illustrated in  FIG. 1 . The train presence detection apparatus  1  illustrated in  FIG. 9  includes a processor  101 , a storage circuit  102 , a receiver  103 , a transmitter  104 , and an input unit  105 . The processor  101  uses received information to perform calculation and control by software, and the storage circuit  102  stores received information or information and software necessary for the processor  101  to perform calculation and control. The receiver  103  is an interface for receiving information from the outside. The transmitter  104  is an interface for transmitting information to the outside. The input unit  105  is an input interface for receiving input of various types of information. A plurality of individual processors  101 , storage circuits  102 , receivers  103 , transmitters  104 , and input units  105  may be provided. The input reception unit  2  illustrated in  FIG. 1  is realized by the input unit  105 . The information acquisition unit  3  is implemented by the processor  101  and the receiver  103 . The designated section determination unit  4 , the presence determination unit  5 , and the approach determination unit  6  are implemented by the processor  101 . The train control unit  7  is implemented by the processor  101  and the transmitter  104 . The track database  8  is implemented by the storage circuit  102 . 
     The train presence detection apparatus  1  according to the first embodiment of the present invention includes the information acquisition unit  3  that acquires position information on the first end point P 1  and the second end point P 2  located in the loop line section L 1  and virtual block presence/absence information that indicates whether the virtual block VB indicating a specific position in the loop line section L 1  is included in a designated section that is any of the first section A 1  and the second section A 2  in which the first end point P 1  and the second end point P 2  are located at both ends; the designated section determination unit  4  that determines which of the first section A 1  and the second section A 2  is the designated section on the basis of the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information acquired by the information acquisition unit  3 ; and the presence determination unit  5  that determines whether the train  20  is present in the designated section determined by the designated section determination unit  4 . Consequently, it is possible to determine the designated section designated in the loop line section L 1  and to determine whether the train  20  is present in the designated section. 
     The train presence detection apparatus  1  according to the first embodiment of the present invention includes the input reception unit  2  that receives input of the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information, and the information acquisition unit  3  acquires the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information received by the input reception unit  2 . Consequently, it is possible to acquire information on an appropriate designated section in accordance with a situation. 
     According to the train presence detection apparatus  1  of the first embodiment of the present invention, the input reception unit  2  is provided in the ground apparatus  10  that performs wireless communication with the train  20 . Consequently, it is possible to input information on an appropriate designated section in accordance with a situation in the loop line section L 1 . 
     The train presence detection apparatus  1  according to the first embodiment of the present invention includes the approach determination unit  6  that, when the presence determination unit  5  determines that the train  20  is not present in the designated section, determines whether the distance from the train  20  to a starting end point is within a specific range, the starting end point being any of the first end point P 1  and the second end point P 2  that is closer to the train  20  in the traveling direction of the train  20 . Consequently, even in a case where the train  20  is not present in the designated section, when the designated section is the temporary speed limit section or the train protection section, it is possible to determine whether the train  20  is approaching the designated section. 
     In the present embodiment, the description of the train presence detection apparatus  1  is given by taking the example in which the train presence detection apparatus  1  is configured from the ground apparatus  10  that performs wireless communication with the train  20  via the ground wireless apparatus  9 , but there is no limitation thereto.  FIG. 10  is a block diagram illustrating another example of the configuration of the train presence detection apparatus according to the first embodiment of the present invention. As illustrated in  FIG. 10 , the on-board apparatus  21  included in the train  20  may be configured as the train presence detection apparatus  1 . Regarding configurations and the like similar to those of the train presence detection apparatus  1  illustrated in  FIG. 1 , same reference numerals are given thereto, and detailed descriptions thereof will be omitted. 
     The train presence detection apparatus  1  illustrated in  FIG. 10  includes a presence position calculation unit  11  that acquires presence position information on the train  20 , in addition to the input reception unit  2  that receives input of information, the information acquisition unit  3  that acquires various types of information, the designated section determination unit  4  that determines a designated section designated in the loop line section L 1  on the basis of the information acquired by the information acquisition unit  3 , the presence determination unit  5  that determines whether the train  20  is present in the designated section determined by the designated section determination unit  4 , the approach determination unit  6  that determines whether the train  20  is approaching the designated section, the train control unit  7  that generates train control information for controlling the train  20  traveling in the loop line section L 1 , and the track database  8  that stores route information that is information on a route on which the train  20  travels. 
     For example, when the train  20  passes the ground coil installed at the starting end of each of the blocks [B 1001 ] to [B 1010 ] set in the loop line section L, the presence position calculation unit  11  receives ground coil information detected by the pickup coil in the train  20  as pickup coil information, detects the position of the ground coil by the pickup coil information, uses an absolute position of the ground coil as a reference position, calculates a travel distance from the reference position, for example, on the basis of speed information detected by a rate generator attached to an axle, and obtains an intra-block position that is a position of the train  20  in a block, thereby calculating presence position information on the train  20  to which the presence position calculation unit  11  belongs. The presence position calculation unit  11  outputs the calculated presence position information on the train  20  to the information acquisition unit  3 . 
     Although not illustrated in detail, the train presence detection apparatus  1  may be configured as a train control system including the ground apparatus  10  and the on-board apparatus  21 . When the train presence detection apparatus  1  is configured as the train control system including the ground apparatus  10  and the on-board apparatus  21 , a configuration may be employed in which, for example, the ground apparatus  10  has functions of the input reception unit  2 , the information acquisition unit  3 , and the designated section determination unit  4 , and the on-board apparatus  21  has functions of the presence determination unit  5 , the approach determination unit  6 , the train control unit  7 , the track database  8 , and the presence position calculation unit  11 . In such a case, in the train presence detection apparatus  1 , the input reception unit  2  of the ground apparatus  10  receives input of the position information on the first end point P 1  and the second end point P 2  located at both ends of the designated section and the virtual block presence/absence information that indicates whether the virtual block VB indicating a specific position in the loop line section is included in the designated section, and outputs the above pieces of information to the information acquisition unit  3 . The information acquisition unit  3  acquires the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information that are input information received by the input reception unit  2 , and outputs the above pieces of information to the designated section determination unit  4 . On the basis of the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information acquired by the information acquisition unit  3 , the designated section determination unit  4  determines which of the first section A 1  and the second section A 2  is the designated section, generates a block sequence of the section (designated section) between two points that are the first end point P 1  and the second end point P 2 , as illustrated in each of  FIGS. 6 and 7 , and transmits the block sequence to the on-board apparatus  21  via the ground wireless apparatus  9 . When the on-board apparatus  21  receives, via the on-board wireless apparatus  22 , information on the block sequence indicating the designated section generated by the designated section determination unit  4 , the presence determination unit  5  may determine whether the train  20  is present in the designated section by determining whether the presence position of the train  20  is included in the block sequence indicating the designated section. 
     Second Embodiment 
     Next, a train presence detection apparatus  1   a  according to a second embodiment of the present invention will be described.  FIG. 11  is a block diagram illustrating an example of a configuration of the train presence detection apparatus according to the second embodiment of the present invention. As illustrated in  FIG. 11 , the train presence detection apparatus  1   a  includes, instead of the input reception unit  2  included in the train presence detection apparatus  1  illustrated in  FIG. 1  according to the first embodiment, a sensor  12  that detects a state in the loop line section L or around the loop line section L and a sensor information database  13 . Regarding configurations and the like similar to those of the train presence detection apparatus  1  according to the first embodiment of the present invention, same reference numerals are given thereto, and detailed descriptions thereof will be omitted. 
     Multiple sensors  12  are installed at specific intervals in the loop line section L 1  or around the loop line section L 1 , for example, and each sensor  12  detects a state in the loop line section L 1  or around the loop line section L 1 . Examples of sensors usable as the sensors  12  include a wind speed sensor that detects a wind speed around the loop line section L 1 , a rock fall detection sensor that detects occurrence of a rock fall on a slope or the like along the loop line section L 1 , a seismic sensor that detects occurrence of an earthquake in an area around the position of the loop line section L 1 , a liquid level sensor that detects the height or the like of the water surface of a river that the loop line section L 1  crosses or a river along the loop line section L 1 , and various types of weather sensors that detect the amounts of snowfall, rainfall, and the like in the loop line section L 1  or around the loop line section L 1 . When any sensor  12  detects a specific state for which travel control of the train  20  needs to be performed, the sensor  12  transmits, to the information acquisition unit  3  via the ground wireless apparatus  9 , its own sensor ID the sensor  12  has. An example of the specific state when the sensor  12  is a wind speed sensor is a state in which wind is blowing at a speed higher than a predetermined wind speed. 
       FIG. 12  is a diagram illustrating an example of a data configuration including the virtual block presence/absence information stored in the sensor information database. For example, as illustrated in  FIG. 12 , the sensor information database  13  stores, in association with the sensor ID, the position information on the first end point P 1  and the second end point P 2  located at both ends of the designated section and the virtual block presence/absence information indicating whether the virtual block VB is included in the designated section. In the train presence detection apparatus  1   a , when the sensor  12  detects a specific state and when the information acquisition unit  3  receives the sensor ID from the sensor  12 , the information acquisition unit  3  accesses the sensor information database  13  on the basis of the received sensor ID, and acquires the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information indicating whether the virtual block VB is included in the designated section, where the position information and the virtual block presence/absence information correspond to the received sensor ID. Thus, the train presence detection apparatus  1   a  can determine the designated section by the designated section determination unit  4  similarly to the train presence detection apparatus  1  illustrated in  FIG. 1 . The position information on the first end point P 1  and the second end point P 2  is not designated as a coordinate value of the virtual block VB, similarly to the train presence detection apparatus  1  according to the first embodiment. That is, the first end point Pl, the second end point P 2 , and the virtual block VB are all set to have different coordinate values. When it is desired to designate either the first end point P 1  or the second end point P 2  as the coordinate value of the virtual block VB, the position information on the first end point P 1  or the second end point P 2  may be stored such that the virtual block VB is included in the designated section with allowance. Although only one sensor  12  is illustrated in  FIG. 11 , multiple sensors  12  are installed at specific intervals in the loop line section L 1  or around the loop line section L 1 , and different types of multiple sensors  12  may be installed in accordance with a situation of a place where the loop line section L 1  passes.  FIG. 11  illustrates the example in which the sensor information database  13  is provided in the ground apparatus  10 , but the sensor information database  13  may be provided outside the ground apparatus  10 . Although  FIG. 11  illustrates the example in which the information acquisition unit  3  acquires information from the sensor  12  via the ground wireless apparatus  9 , there is no limitation thereto, and the information acquisition unit  3  may be configured to acquire information via a wired connection. Components from which the information acquisition unit  3  acquires the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information are not limited to the input reception unit  2  and the sensor information database  13 , and the information acquisition unit  3  may be configured to acquire the above pieces of information from another device or the like. 
     The train presence detection apparatus  1   a  according to the second embodiment of the present invention includes the sensors  12  each of which detects a state in the loop line section L 1  or around the loop line section L 1  and the sensor information database  13  that stores, in association with an ID each sensor  12  has, the position information on the first end point of P 1  and the second end point P 2  and the virtual block presence/absence information. When any sensor  12  detects a specific state, the information acquisition unit  3  acquires the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information from the sensor information database  13  on the basis of the ID the sensor  12  has. Consequently, it is possible to determine the designated section efficiently in accordance with a state in the loop line section L 1  or around the loop line section L 1  detected by the sensor  12 . 
       FIG. 13  is a block diagram illustrating another example of the configuration of the train presence detection apparatus according to the second embodiment of the present invention. Similarly to the train presence detection apparatus  1  according to the first embodiment, the train presence detection apparatus  1   a  according to the second embodiment may also be configured to include the sensor information database  13  in the on-board apparatus  21  included in the train, as illustrated in  FIG. 13 , in addition to the information acquisition unit  3 , the designated section determination unit  4 , the presence determination unit  5 , the approach determination unit  6 , the train control unit  7 , the track database  8 , and the presence position calculation unit  11 . In the train presence detection apparatus  1   a  illustrated in  FIG. 13 , when the sensor  12  detects a specific state for which travel control of the train  20  needs to be performed, the sensor  12  transmits its own sensor ID the sensor  12  has to the on-board wireless apparatus  22  via the ground wireless apparatus  9 , and the on-board wireless apparatus  22  transmits the sensor ID to the information acquisition unit  3 . Then, the information acquisition unit  3  accesses the sensor information database  13  on the basis of the received sensor ID, and acquires the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information indicating whether the virtual block VB is included in the designated section, where the position information and the virtual block presence/absence information correspond to the received sensor ID. Thus, the train presence detection apparatus  1   a  illustrated in  FIG. 13  can determine the designated section by the designated section determination unit  4 . Although not illustrated in detail, the train presence detection apparatus  1   a  may also be configured as a train control system including the ground apparatus  10  and the on-board apparatus  21  similarly to the train presence detection apparatus  1  according to the first embodiment. 
       FIG. 14  is a block diagram illustrating still another example of the configuration of the train presence detection apparatus according to the second embodiment of the present invention. In the train presence detection apparatus  1   a  illustrated in  FIG. 14 , for example, the sensor  12  has stored in advance the position information on the first end point Pl, the position information on the second end point P 2 , and the virtual block presence/absence information in a storage unit (not illustrated), and is configured to transmit the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information to the information acquisition unit  3  via the ground wireless apparatus  9  when a specific state is detected. Thus, in the train presence detection apparatus  1   a  illustrated in  FIG. 14 , although the ground apparatus  10  does not include the sensor information database  13 , the information acquisition unit  3  can acquire the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information. 
       FIG. 15  is a diagram illustrating an example of a virtual block in a case where a loop line section L 2 , which is a second line section formed in a loop, is connected adjacent to the loop line section L 1 . Although  FIG. 2  illustrates the example in which the virtual block VB is set in one loop line section L 1 , for example, as illustrated in  FIG. 15 , when the loop line sections L 1  and L 2  different from each other are adjacently connected, the virtual block VB may be set at a connection point where the loop line sections L 1  and L 2  are connected. Thus, the loop line section L 1  and the loop line section L 2  can share and use the virtual block VB, and thereby the number of virtual blocks VB can be reduced by one as compared with a case where the virtual block VB is provided in each of the loop line section L 1  and the loop line section L 2 , which is efficient. 
     Third Embodiment 
     Next, a train presence detection apparatus  1   b  according to a third embodiment of the present invention will be described.  FIG. 16  is a block diagram illustrating an example of a configuration of the train presence detection apparatus according to the third embodiment of the present invention.  FIG. 17  is a diagram illustrating examples of blocks set in the first line section formed in a loop and direction information. In the train presence detection apparatus  1   b  according to the third embodiment of the present invention, as illustrated in  FIGS. 16 and 17 , the input reception unit  2  receives input of the position information on the first end point P 1  and the second end point P 2  located in the loop line section L 1 , and input of the direction information for indicating in which direction (clockwise or counterclockwise direction) from the first end point (starting end) P 1  to the second end point (terminating end) P 2  the designated section is located, the designated section being any of the first section A 1  and the second section A 2  in which the first end point P 1  and the second end point P 2  are located at both ends, and the information acquisition unit  3  acquires the position information on the first end point P 1  and the second end point P 2  and the direction information received by the input reception unit  2 . Regarding configurations and the like similar to those of the train presence detection apparatus  1  according to the first embodiment of the present invention, same reference numerals are given thereto, and detailed descriptions thereof will be omitted. 
     In the train presence detection apparatus  1   b , the designated section determination unit  4  determines which of the first section A 1  and the second section A 2  is the designated section on the basis of the position information on the first end point P 1  and the second end point P 2  and the direction information acquired by the information acquisition unit  3 . It is impossible to determine which of the first section A 1  and the second section A 2  is the designated section only with the position information on the first end point P 1  and the second end point P 2  indicating the positions of both ends of the designated section, as illustrated in  FIG. 17 . Therefore, the train presence detection apparatus  1   b  uses the direction information for indicating in which direction (clockwise or counterclockwise direction) from the first end point P 1  to the second end point P 2  the designated section is located. 
       FIG. 18  is a diagram illustrating an example of a case where the designated section is located in a clockwise direction from the first end point to the second end point.  FIG. 19  is a diagram illustrating an example of a case where the designated section is located in a counterclockwise direction from the first end point to the second end point. For example, when the designated section determination unit  4  acquires, as the direction information, information indicating that the designated section is located in the clockwise direction from the first end point P 1  to the second end point P 2 , as illustrated in  FIG. 18 , the designated section determination unit  4  determines that the first section A 1  that is located in the clockwise direction from the first end point P 1  to the second end point P 2  is the designated section. Alternatively, when the designated section determination unit  4  acquires, as the direction information, information indicating that the designated section is located in the counterclockwise direction from the first end point P 1  to the second end point P 2 , as illustrated in  FIG. 19 , the designated section determination unit  4  determines that the second section A 2  that is located in the counterclockwise direction from the first end point P 1  to the second end point P 2  is the designated section. In addition, when the designated section is determined, the designated section determination unit  4  generates a block sequence of the section (designated section) between two points that are the first end point P 1  and the second end point P 2 , as illustrated in each of  FIGS. 6 and 7 , similarly to the train presence detection apparatus  1  illustrated in  FIG. 1 . The presence determination unit  5  determines whether the presence position (kilometrage) of the train  20  is included in the block sequence generated by the designated section determination unit  4 , thereby determining whether the train  20  is present in the designated section. 
       FIG. 20  is a flowchart illustrating an example of a flow of processes performed by the train presence detection apparatus according to the third embodiment of the present invention. Hereinafter, the flow of processes performed by the train presence detection apparatus  1   b  will be described with reference to the flowchart of  FIG. 20 . In the train presence detection apparatus  1   b  according to the present embodiment, as illustrated in  FIG. 20 , the information acquisition unit  3  first determines whether the position information on the first end point P 1  and the second end point P 2  and the direction information, which are input information received by the input reception unit  2 , have been acquired (S 201 ). When the information acquisition unit  3  determines that the position information on the first end point P 1  and the second end point P 2  and the direction information have not been acquired (S 201 : No), the information acquisition unit  3  again determines whether the position information on the first end point P 1  and the second end point P 2  and the direction information have been acquired (S 201 ). That is, the information acquisition unit  3  repeats the determination of S 201  until the position information on the first end point P 1  and the second end point P 2  and the direction information are acquired. When the information acquisition unit  3  determines that the position information on the first end point P 1  and the second end point P 2  and the direction information have been acquired (S 201 : Yes), the information acquisition unit  3  outputs the position information on the first end point P 1  and the second end point P 2  and the direction information thus acquired to the designated section determination unit  4 . 
     On the basis of the position information on the first end point P 1  and the second end point P 2  and the direction information received from the information acquisition unit  3 , the designated section determination unit  4  determines which of the first section A 1  and the second section A 2  in which the first end point P 1  and the second end point P 2  are located at both ends is the designated section, and generates a block sequence indicating the section (designated section) between two points that are the first end point P 1  and the second end point P 2  (S 202 ). 
     The presence determination unit  5  determines whether the front end position or the rear end position of the train  20  is included in the block sequence of the designated section on the basis of the presence position information on the train  20  acquired by the information acquisition unit  3  and the information on the designated section determined by the designated section determination unit  4  (S 203 ). For example, as illustrated in  FIG. 18 , when the designated section determination unit  4  determines that the first section A 1  illustrated in  FIG. 17  is the designated section, the presence determination unit  5  first determines whether kilometrage at the front end position of the train  20  is less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof. When the presence determination unit  5  determines that the kilometrage at the front end position of the train  20  is less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof (S 203 : Yes), the presence determination unit  5  determines that the train  20  is present in the designated section A 1  (S 204 ), and ends the presence detection process performed by the train presence detection apparatus  1   b . That is, as illustrated in  FIG. 17 , the train  20   a  present in the block [B 1002 ] whose kilometrage is 100 to 200 is determined by the presence determination unit  5  to be present in the designated section A 1 . 
     On the other hand, when the presence determination unit  5  determines that the kilometrage at the front end position of the train  20  is not less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  and not greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof, the presence determination unit  5  next determines whether the kilometrage at the rear end position of the train  20  is less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof. When the presence determination unit  5  determines that the kilometrage at the rear end position of the train  20  is less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof (S 203 : Yes), the presence determination unit  5  determines that the train  20  is present in the designated section (S 204 ), and ends the presence detection process performed by the train presence detection apparatus  1   b . However, when the presence determination unit  5  determines that the kilometrage at the rear end position of the train  20  is not less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  and not greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof, that is, when the presence determination unit  5  determines that neither the kilometrage at the front end position of the train  20  nor that at the rear end position thereof is included in the designated section A 1  (S 203 : No), the presence determination unit  5  determines that the train  20  is not present in the designated section (S 205 ). That is, as illustrated in  FIG. 17 , the train  20   b  present in the block [B 1004 ] whose kilometrage is 300 to 400 and the train  20   c  present in the block [B 1006 ] whose kilometrage is 500 to 600 are determined by the presence determination unit  5  not to be present in the designated section A 1 . 
     When the presence determination unit  5  determines that the train  20  is not present in the designated section (S 205 ), then the approach determination unit  6  determines whether the starting end point that is an end point of the designated section closer to the train  20  in a traveling direction of the train  20  is included in the route on which the train  20  travels, the route being indicated by the route information (S 206 ). For example, when the train  20   b  is present in the block [B 1004 ] as in illustrated in  FIG. 17 , the route information in accordance with which the train  20   b  travels is the route R 1018  and indicates a travel route from the kilometrage (500) at the position of the terminating end of the block [B 1005 ] to the kilometrage (200) at the position of the starting end of the block [B 1003 ] in the clockwise direction, and therefore, the approach determination unit  6  determines that the first end point P 1  (kilometrage is 240) that is the starting end point of the designated section A 1  is included in the route R 1018  of the train  20   b  (S 206 : Yes). Then, the approach determination unit  6  determines that the train  20   b  is approaching the designated section A 1  (S 207 ), and ends the presence detection process performed by the train presence detection apparatus  1   b.    
     On the other hand, for example, when the train  20   c  is present in the block [B 1006 ] as in illustrated in  FIG. 17 , the route information in accordance with which the train  20   c  travels is the route R 1017  and indicates a travel route from the kilometrage (700) at the position of the terminating end of the block [B 1007 ] to the kilometrage (400) at the position of the starting end of the block [B 1005 ] in the clockwise direction, and therefore, the approach determination unit  6  determines that the first end point P 1  (kilometrage is 240) that is the starting end point of the designated section A 1  is not included in the route R 1017  of the train  20   c  (S 206 : No). Then, the approach determination unit  6  determines that the train  20   c  is not approaching the designated section A 1  (S 208 ), and ends the presence detection process performed by the train presence detection apparatus  1   b . The train presence detection apparatus  1   b  according to the third embodiment described above can also be implemented by a hardware configuration similar to that of the train presence detection apparatus  1 . 
     The train presence detection apparatus  1   b  according to the third embodiment of the present invention includes the information acquisition unit  3  that acquires position information on the first end point P 1  and the second end point P 2  located in the loop line section L 1  and direction information for indicating in which direction from the first end point P 1  to the second end point P 2  the designated section that is any of the first section A 1  and the second section A 2  in which the first end point P 1  and the second end point P 2  are located at both ends is located; the designated section determination unit  4  that determines which of the first section A 1  and the second section A 2  is the designated section on the basis of the position information on the first end point P 1  and the second end point P 2  and the direction information acquired by the information acquisition unit  3 ; and the presence determination unit  5  that determines whether the train  20  is present in the designated section determined by the designated section determination unit  4 . Consequently, it is possible to determine the designated section designated in the loop line section L 1  and to determine whether the train  20  is present in the designated section. 
     In the present embodiment, the description of the train presence detection apparatus  1   b  is given by taking the example in which the train presence detection apparatus  1   b  is configured from the ground apparatus  10  that performs wireless communication with the train  20  via the ground wireless apparatus  9 , but there is no limitation thereto. The on-board apparatus  21  included in the train  20  may be configured as the train presence detection apparatus  1   b , similarly to the train presence detection apparatus  1  illustrated in  FIG. 10 . The train presence detection apparatus  1   b  may be configured as a train control system including the ground apparatus  10  and the on-board apparatus  21 . 
     Fourth Embodiment 
     Next, a train presence detection apparatus  1   c  according to a fourth embodiment of the present invention will be described.  FIG. 21  is a block diagram illustrating an example of a configuration of the train presence detection apparatus according to the fourth embodiment of the present invention. As illustrated in  FIG. 21 , the train presence detection apparatus  1   c  according to the fourth embodiment of the present invention includes, instead of the input reception unit  2  included in the train presence detection apparatus  1   b  illustrated in  FIG. 16  according to the third embodiment, the sensor  12  that detects a state in the loop line section L 1  or around the loop line section L 1  and the sensor information database  13 . Regarding configurations and the like similar to those of the train presence detection apparatus  1   b  according to the third embodiment of the present invention, same reference numerals are given thereto, and detailed descriptions thereof will be omitted. 
     Multiple sensors  12  are installed at specific intervals in the loop line section L 1  or around the loop line section L 1 , for example, and each sensor  12  detects a state in the loop line section L 1  or around the loop line section L 1 . Examples of sensors usable as the sensors  12  include the wind speed sensor, the rock fall detection sensor, the seismic sensor, the liquid level sensor, and the various types of weather sensors described above. When any sensor  12  detects a specific state for which travel control of the train  20  needs to be performed, the sensor  12  transmits, to the information acquisition unit  3  via the ground wireless apparatus  9 , its own sensor ID the sensor  12  has. 
       FIG. 22  is a diagram illustrating an example of a data configuration including direction information stored in the sensor information database. For example, as illustrated in  FIG. 22 , the sensor information database  13  stores, in association with the sensor ID, the position information on the first end point P 1  and the second end point P 2  located at both ends of the designated section and direction information for indicating in which direction (clockwise or counterclockwise direction) from the first end point P 1  to the second end point P 2  the designated section that is any of the first section A 1  and the second section A 2  in which the first end point P 1  and the second end point P 2  are located at both ends is located. In the train presence detection apparatus  1   c , when any sensor  12  detects a specific state and when the information acquisition unit  3  receives the sensor ID from the sensor  12 , the information acquisition unit  3  accesses the sensor information database  13  on the basis of the received sensor ID, and acquires the position information on the first end point P 1  and the second end point P 2  and the direction information, where the position information and the direction information correspond to the received sensor ID. Thus, the train presence detection apparatus  1   c  can determine the designated section by the designated section determination unit  4  similarly to the train presence detection apparatus  1   b  illustrated in  FIG. 16 . 
     The train presence detection apparatus  1   c  according to the fourth embodiment of the present invention includes the sensors  12  each of which detects a state in the loop line section L 1  or around the loop line section L 1  and the sensor information database  13  that stores, in association with an ID each sensor  12  has, the position information on the first end point of P 1  and the second end point P 2  and the direction information, and when any sensor  12  detects a specific state, the information acquisition unit  3  acquires the position information on the first end point P 1  and the second end point P 2  and the direction information from the sensor information database  13  on the basis of the ID the sensor  12  has. Consequently, it is possible to determine the designated section efficiently in accordance with a state in the loop line section L 1  or around the loop line section L 1  detected by the sensor  12 . 
     Similarly to the train presence detection apparatus  1  according to the first embodiment, the train presence detection apparatus  1   c  according to the fourth embodiment may also be configured to include the sensor information database  13  in the on-board apparatus  21  included in the train, in addition to the input reception unit  2 , the information acquisition unit  3 , the designated section determination unit  4 , the presence determination unit  5 , the approach determination unit  6 , the train control unit  7 , the track database  8 , and the presence position calculation unit  11 . In such a case, similarly to the train presence detection apparatus  1   a  illustrated in  FIG. 13 , for example, a configuration is employed in which when the sensor  12  detects a specific state for which travel control of the train  20  needs to be performed, the sensor  12  transmits its own sensor ID the sensor  12  has to the on-board wireless apparatus  22  via the ground wireless apparatus  9 , and the on-board wireless apparatus  22  transmits the sensor ID to the information acquisition unit  3 . The train presence detection apparatus  1   c  may also be configured as a train control system including the ground apparatus  10  and the on-board apparatus  21 . 
       FIG. 23  is a block diagram illustrating another example of the configuration of the train presence detection apparatus according to the fourth embodiment of the present invention. In the train presence detection apparatus  1   c  illustrated in  FIG. 23 , for example, the sensor  12  has stored in advance the position information on the first end point Pl, the position information on the second end point P 2 , and the direction information in a storage unit (not illustrated), and is configured to transmit the position information on the first end point P 1  and the second end point P 2  and the direction information to the information acquisition unit  3  via the ground wireless apparatus  9  when a specific state is detected. Thus, in the train presence detection apparatus  1   c  illustrated in  FIG. 23 , although the ground apparatus  10  does not include the sensor information database  13 , the information acquisition unit  3  can acquire the position information on the first end point P 1  and the second end point P 2  and the direction information. 
     Fifth Embodiment 
     Next, a train presence detection apparatus  1   d  according to a fifth embodiment of the present invention will be described.  FIG. 24  is a block diagram illustrating an example of a configuration of the train presence detection apparatus according to the fifth embodiment of the present invention.  FIG. 25  is a diagram illustrating an example of a configuration in which a third line section L 3 , through which a train can enter the first line section L 1  formed in a loop, is connected to the first line section L 1 . As illustrated in  FIG. 24 , the train presence detection apparatus  1   d  according to the fifth embodiment of the present invention further includes a connection point presence/absence determination unit  14  in addition to the configuration included in the train presence detection apparatus  1  illustrated in  FIG. 1  according to the first embodiment. Regarding configurations and the like similar to those of the train presence detection apparatus  1  according to the first embodiment of the present invention, same reference numerals are given thereto, and detailed descriptions thereof will be omitted. 
     In the train presence detection apparatus  1   d , the track database  8  stores connection point position information in advance, in addition to the route information. The connection point position information is information that indicates, as illustrated in  FIG. 25 , the position of a connection point P 3  where the loop line section L 1  that is a first line section formed in a loop and the third line section L 3  through which a train can enter the loop line section L 1  are connected. The connection point position information is expressed, for example, by a block number and an intra-block position, similarly to the position information on the first end point P 1  and the second end point P 2 . For example,  FIG. 25  illustrates an example in which the connection point position information is expressed as  580  obtained by adding 80 that is a coordinate value at the intra-block position in the block [B 1006 ] to 500 that is kilometrage (coordinate value) at a reference point of the block [B 1006 ]. The third line section L 3  is not particularly limited as long as a train can enter the first line section L 1  therethrough, and the third line section L 3  may be a line section formed in a loop. 
     As illustrated in  FIG. 24 , the information acquisition unit  3  of the train presence detection apparatus  1   d  can acquire route information and connection point position information from the track database  8 . The connection point presence/absence determination unit  14  determines whether the connection point P 3  is located in the designated section. For example, when the designated section determination unit  4  determines that the first section A 1  that includes the virtual block VB illustrated in  FIG. 25  is the designated section, the connection point presence/absence determination unit  14  uses the connection point position information to determine whether the position (kilometrage) of the connection point P 3  is included in the block sequence of the designated section (first section A 1 ) illustrated in  FIG. 4 , thereby determining whether the connection point P 3  is located in the designated section A 1 . In the example of  FIG. 25 , when the designated section determination unit  4  determines that the first section A 1  is the designated section, the connection point presence/absence determination unit  14  determines that the connection point P 3  is not located in the designated section A 1  because kilometrage (580) at the position of the connection point P 3  is not included in the block sequence of less than or equal to the kilometrage (240) at the position of the first end point P 1  of the designated section A 1  illustrated in  FIG. 4  or greater than or equal to the kilometrage (800) at the position of the second end point P 2  thereof. Alternatively, when the designated section determination unit  4  determines that the second section A 2  that does not include the virtual block VB is the designated section, the connection point presence/absence determination unit  14  determines that the connection point P 3  is located in the designated section A 2  because the kilometrage (580) at the position of the connection point P 3  is included in the block sequence from the kilometrage (240) at the position of the first end point P 1  of the designated section A 2  illustrated in  FIG. 5  to the kilometrage (800) at the position of the second end point P 2  thereof. 
     An approach determination unit  6   a  determines whether the train  20  is approaching a designated section. When the connection point presence/absence determination unit  14  determines that the connection point P 3  is located in the designated section, the approach determination unit  6   a  determines whether a distance D from the train  20  traveling from the third line section L 3  toward the loop line section L 1  to the connection point P 3  is within a specific range. Even in a case where the train  20  is not traveling in the loop line section L 1  but traveling in the third line section L 3 , when the connection point P 3  to the loop line section L 1  the train enters is located in the designated section that is a temporary speed limit section or a train protection section, there may be a case where it is necessary to reduce the traveling speed of the train  20  or to stop the train  20  when the train  20  approaches the designated section. Therefore, the approach determination unit  6   a  determines whether the train  20  traveling from the third line section L 3  toward the loop line section L 1  is approaching the designated section. 
     For example, as illustrated in  FIG. 24 , the approach determination unit  6   a  can determine whether the train  20  is approaching the designated section by using the presence position information and the connection point position information. The approach determination unit  6   a  uses, for example, the presence position information and the connection point position information to calculate the distance D from the front end position of the train  20  to the connection point P 3 , and determines whether the distance D falls in a specific distance range set depending on the types of the designated section and the like, thereby determining whether the train  20  is approaching the designated section. The method for determining whether the train  20  is approaching the designated section performed by the approach determination unit  6   a  is not limited to the above method. For example, the route information that indicates a route on which the train  20  travels and the connection point position information may be used to determine whether the connection point P 3  is included in a route on which the train  20  travels, the route being indicated by the route information, and when the connection point P 3  is included in the route on which the train  20  travels, it may be determined that the train  20  is approaching the designated section. 
     When it is determined by the presence determination unit  5  that the train  20  is present in the designated section or when it is determined by the approach determination unit  6   a  that the train  20  is approaching the designated section, the train control unit  7  generates train control information for performing travel control such that the traveling speed of the train  20  is reduced to a specific speed or lower or train control information for stopping the train  20 , for example, depending on the types of the designated section. The train control information generated by the train control unit  7  is transmitted to the train  20  via the ground wireless apparatus  9 . 
       FIG. 26  is a flowchart illustrating an example of a flow of processes performed by the train presence detection apparatus  1   d  according to the fifth embodiment of the present invention. Hereinafter, the flow of processes performed by the train presence detection apparatus  1   d  will be described with reference to the flowchart of  FIG. 26 . In the train presence detection apparatus  1   d  according to the present embodiment, as illustrated in  FIG. 26 , the information acquisition unit  3  first determines whether the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information, which are input information received by the input reception unit  2 , have been acquired (S 301 ). When the information acquisition unit  3  determines that the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information have not been acquired (S 301 : No), the information acquisition unit  3  again determines whether the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information have been acquired (S 301 ). That is, the information acquisition unit  3  repeats the determination of S 301  until the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information are acquired. When the information acquisition unit  3  determines that the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information have been acquired (S 301 : Yes), the information acquisition unit  3  outputs the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information thus acquired to the designated section determination unit  4 . 
     On the basis of the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information received from the information acquisition unit  3 , the designated section determination unit  4  determines which of the first section A 1  and the second section A 2  in which the first end point P 1  and the second end point P 2  are located at both ends is the designated section, and generates a block sequence indicating the section (designated section) between two points that are the first end point P 1  and the second end point P 2  (S 302 ). 
     The presence determination unit  5  determines whether the front end position or the rear end position of the train  20  is included in the block sequence of the designated section on the basis of the presence position information on the train  20  acquired by the information acquisition unit  3  and the information on the designated section determined by the designated section determination unit  4  (S 303 ). When the presence determination unit  5  determines that the kilometrage at the front end position or the rear end position of the train  20  is included in the designated section (S 303 : Yes), for example, the presence determination unit  5  determines that the train  20  is present in the designated section (S 304 ), and ends the presence detection process performed by the train presence detection apparatus  1   d.    
     When the presence determination unit  5  determines that neither the kilometrage at the front end position of the train  20  nor that at the rear end position thereof is included in the designated section (S 303 : No), the presence determination unit  5  determines that the train  20  is not present in the designated section (S 305 ). 
     When the presence determination unit  5  determines that the train  20  is not present in the designated section, next, the connection point presence/absence determination unit  14  determines whether the connection point P 3  is located in the designated section (S 306 ). When the connection point presence/absence determination unit  14  determines that the connection point P 3  is located in the designated section (S 306 : Yes), the approach determination unit  6   a  determines whether the distance D from the train  20  traveling from the third line section L 3  toward the loop line section L 1  to the connection point P 3  is within a specific range (S 307 ). 
     When the approach determination unit  6   a  determines that the distance D from the train  20  to the connection point P 3  is within the specific range (S 307 : Yes), the approach determination unit  6   a  determines that the train  20  is approaching the designated section (S 308 ), and ends the presence detection process performed by the train presence detection apparatus  1   d.    
     On the other hand, when the approach determination unit  6   a  determines that the distance D from the train  20  to the connection point P 3  is not within the specific range (S 307 : No), the approach determination unit  6   a  determines that the train  20  is not approaching the designated section (S 309 ), and ends the presence detection process performed by the train presence detection apparatus  1   d . When the connection point presence/absence determination unit  14  determines that the connection point P 3  is not located in the designated section (S 306 : No), the approach determination unit  6   a  determines that the train  20  is not approaching the designated section (S 309 ), and ends the presence detection process performed by the train presence detection apparatus  1   d.    
     In the flowchart illustrated in  FIG. 26 , the example is illustrated in which the presence determination unit  5  determines that the train  20  is not present in the designated section (S 305 ), and then the connection point presence/absence determination unit  14  determines whether the connection point P 3  is located in the designated section (S 306 ). However, in the train presence detection apparatus  1   d , after the process of S 305 , the approach determination unit  6   a  may determine whether the starting end point that is an end point of the designated section closer to the train  20  in a traveling direction of the train  20  is included in a route on which the train  20  travels, the route being indicated by the route information, similarly to the process of S 106  illustrated in the flowchart of  FIG. 8 , and when the approach determination unit  6   a  determines that the starting end point of the designated section is not included in the route on which the train  20  travels and which is indicated by the route information, the processes after the process of S 306  may be executed. 
     The train presence detection apparatus  1   d  according to the fifth embodiment of the present invention includes the connection point presence/absence determination unit  14  that, when the presence determination unit  5  determines that the train  20  is not present in the designated section, determines whether the connection point P 3  where the loop line section L 1  and the third line section L 3  are connected is located in the designated section; and the approach determination unit  6   a  that, when the connection point presence/absence determination unit  14  determines that the connection point P 3  is located in the designated section, determines whether the distance D from the train  20  traveling from the third line section L 3  toward the loop line section L 1  to the connection point P 3  is within a specific range. Consequently, even in a case where the train  20  is not traveling in the loop line section L 1  but traveling in the third line section L 3 , when the connection point P 3  to the loop line section L 1  the train enters is located in the designated section, it is possible to determine whether the train  20  is approaching the designated section. 
     In the present embodiment, the description of the train presence detection apparatus  1   d  is given by taking the example in which the train presence detection apparatus  1   d  is configured from the ground apparatus  10  that performs wireless communication with the train  20  via the ground wireless apparatus  9 , but there is no limitation thereto. The on-board apparatus  21  included in the train  20  may be configured as the train presence detection apparatus  1   d , similarly to the train presence detection apparatus  1  illustrated in  FIG. 10 . The train presence detection apparatus  1   d  may be configured as a train control system including the ground apparatus  10  and the on-board apparatus  21 . When the train presence detection apparatus  1   d  is configured as the train control system including the ground apparatus  10  and the on-board apparatus  21 , a configuration may be employed in which, for example, the ground apparatus  10  has functions of the input reception unit  2 , the information acquisition unit  3 , and the designated section determination unit  4 , and the on-board apparatus  21  has functions of the presence determination unit  5 , the approach determination unit  6   a , the train control unit  7 , the track database  8 , and the presence position calculation unit  11 . 
     Regarding the train presence detection apparatus  1   d , the example is indicated in which the input reception unit  2  receives the input of the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information. However, similarly to the train presence detection apparatus  1   a  according to the second embodiment, the train presence detection apparatus  1   d  may include, instead of the input reception unit  2 , the sensor  12  that detects a state in the loop line section L or around the loop line section L, and the sensor information database  13 . Alternatively, similarly to the train presence detection apparatus  1   a  illustrated in  FIG. 14 , a configuration may be employed in which the sensor  12  stores the position information on the first end point Pl, the position information on the second end point P 2 , and the virtual block presence/absence information in advance, and the position information on the first end point P 1  and the second end point P 2  and the virtual block presence/absence information are transmitted to the information acquisition unit  3  via the ground wireless apparatus  9  when a specific state is detected. 
     The present invention is not limited to the above embodiments, and each embodiment can be appropriately modified or omitted without departing from the scope of the concept of the present invention. 
     REFERENCE SIGNS LIST 
       1  to  1   d  train presence detection apparatus;  2  input reception unit;  3  information acquisition unit;  4  designated section determination unit;  5  presence determination unit;  6  approach determination unit;  10  ground apparatus;  12  sensor;  13  sensor information database;  14  connection point presence/absence determination unit;  20  train;  21  on-board apparatus; A 1  first section; A 2  second section; L 1  first line section; L 2  second line section; L 3  third line section; P 1  first end point; P 2  second end point; P 3  connection point.