DESCRIPTION
CONTROL TRANSMISSION DEVICE, MAINTENANCE COMMUNICATION DEVICE, TRAIN MAINTENANCE COMMUNICATION PROGRAM, AND TRAIN
MAINTENANCE SYSTEM
Field
[0001] The present invention relates to a control transmission device, a maintenance communication device, a train maintenance communication program, and a train maintenance system for a train.
Background
[0002] Various instruments mounted on railroad cars need to regularly undergo maintenance and inspection.
[0003] Patent Literature 1 discloses a system for performing maintenance and inspection by using wireless local area network (LAN) communication between a central control device and a wireless-enabled portable terminal device held by an inspection operator.
Citation List
Patent Literature
[0004] Patent Literature 1: Japanese Patent Application
Laid-open No. 2003-344227
Summary
Technical Problem
[0005] However, the above-mentioned conventional
technique has a problem in that the portable terminal can
operate the central control device by wireless
communication but cannot operate on-board devices by
wireless communication.

[0006] The present invention has been made in view of the above, and an object thereof is to enable wireless communication between a portable terminal and on-board devices, and enable wireless connection to a train composition to be subjected to maintenance even in the presence of a plurality of train compositions.
Solution to Problem
[0007] In order to solve the above-mentioned problem and achieve the object, a control transmission device according to the present invention is mounted on a train and includes: a port connectable by wire to an external terminal; a train composition number notification unit that provides notification of a train composition number of the train; and a wireless network ID reception unit that receives a wireless network ID for constructing a wireless network, and the wireless network ID received by the wireless network ID reception unit is generated based on the train composition number provided by the train composition number notification unit.
Advantageous Effects of Invention
[0008] The present invention can achieve the effect of enabling wireless communication between a portable terminal and on-board devices, and enabling wireless connection to a train composition to be subjected to maintenance even in the presence of a plurality of train compositions.
Brief Description of Drawings
[0009] FIG. 1 is a schematic diagram illustrating a configuration of a train maintenance system according to an embodiment.
FIG. 2 is a block diagram illustrating a configuration

of the train maintenance system according to the embodiment.
FIG. 3 is a flowchart illustrating the operation of a control transmission device according to the embodiment.
FIG. 4 is a flowchart illustrating the operation of a maintenance communication device according to the embodiment.
FIG. 5 is a flowchart illustrating the operation of the control transmission device according to the embodiment.
FIG. 6 is a diagram illustrating an example of a tablet terminal in the embodiment.
FIG. 7 is a diagram illustrating a general configuration of hardware that implements the maintenance communication devices and the control transmission devices illustrated in FIG. 2 in the embodiment.
Description of Embodiments
[0010] Hereinafter, a control transmission device, a maintenance communication device, a train maintenance communication program, and a train maintenance system according to an embodiment of the present invention will be described in detail based on the drawings. The present invention is not limited to the embodiment.
[0011] Embodiment.
FIG. 1 is a schematic diagram illustrating a configuration of a train maintenance system according to an embodiment of the present invention. The train maintenance system 10 illustrated in FIG. 1 includes a tablet terminal 1, maintenance communication devices 2a and 2b, and control transmission devices 3a and 3b.
[0012] The tablet terminal 1 is a portable terminal capable of wirelessly communicating with the control transmission devices 3a and 3b using a wireless network constructed by the maintenance communication devices 2a and

2b. On the tablet terminal 1, screens that are the same as or similar to the screens of cab monitors (not illustrated) in cars 4a and 4b are displayed. Because the tablet terminal 1 has portability, an operator who performs maintenance work can check the screens displayed on the cab monitors while visually monitoring the operation of instruments.
[0013] The maintenance communication devices 2a and 2b are devices that construct a unique wireless network 5 for each train composition to be subjected to maintenance. The maintenance communication device 2a is mounted on the car 4a, and the maintenance communication device 2b is mounted on the car 4b.
[0014] The control transmission devices 3a and 3b are car electrical devices each correspondingly mounted on the cab monitors. A train 4 equipped with at least the control transmission devices 3a and 3b includes the car 4a equipped with the control transmission device 3a and the car 4b equipped with the control transmission device 3b. The cars 4a and 4b are cars of the same train composition. When the car 4a is the lead car, the car 4b is the last car, and when the car 4b is the lead car, the car 4a is the last car. Note that the control transmission device 3a is connected by wire to the maintenance communication device 2a which is an external terminal, and the control transmission device 3b is connected by wire to the maintenance communication device 2b which is an external terminal.
[0015] The train maintenance system 10 illustrated in FIG. 1 is used for maintenance and inspection of a train, i.e. railroad cars, at a railyard. Recent railroad cars include a system that allows the operation states of the control transmission devices 3a and 3b, car electrical devices provided in the train, to be checked on the cab

monitors installed in the car 4a and the car 4b, respectively, and allows each of the car electrical devices to be controlled through corresponding one of these cab monitors. Each of the control transmission devices 3a and 3b returns screen configuration data necessary for display on the corresponding cab monitor in response to a request from the cab monitor. The control transmission devices 3a and 3b can also respond to requests for screen configuration data from devices other than the cab monitors. For example, each of the control transmission devices 3a and 3b responds to a request from the tablet terminal 1. However, in many cases, each of the control transmission devices 3a and 3b does not have an instrument for constructing a wireless network or a wireless communication function. Accordingly, each of the control transmission devices 3a and 3b is enabled to wirelessly communicate with the tablet terminal 1 that is a portable terminal, by being connected to the complementary maintenance communication devices 2a and 2b, respectively.
[0016] In such cases, it is necessary to construct a wireless network for use by the tablet terminal 1 and the maintenance communication devices 2a and 2b. However, in the case of railroad car maintenance at a railyard, a plurality of train maintenance systems operates on adjacent pit tracks. Thus, the train maintenance system 10 has the configuration illustrated in FIG. 2 so as to discriminate the wireless network of each train composition.
[0017] FIG. 2 is a block diagram illustrating the configuration of the train maintenance system according to the embodiment of the present invention. The illustration of the train maintenance system 10 in FIG. 2 contains a detailed configuration of the maintenance communication device 2a and the control transmission device 3a in the car

4a illustrated in FIG. 1. Because the configuration of the car 4b is similar to the configuration of the car 4a, it is not depicted in detail. In the following description, components in the car 4a may be assigned the ordinal number “first”, and components in the car 4b may be assigned the ordinal number “second”. The cars 4a and 4b are cars of the same train composition. The car 4a is the lead car, and the car 4b is the last car.
[0018] The maintenance communication device 2a includes a wireless network ID generation unit 21 and a wireless network ID acquisition unit 22. The wireless network ID generation unit 21 generates a wireless network ID using the train composition number as a key in order to construct a unique wireless network for each train composition. The wireless network ID acquisition unit 22 acquires a wireless network ID from a wireless network ID transmission unit 33 or the control transmission device 3b in the car 4b where the other cab is located. An example of a wireless network ID is a service set identifier (SSID).
[0019] Here, wireless network IDs in the present embodiment will be described. In the present embodiment, the wireless network ID generation unit 21 generates a wireless network ID each time it is needed. As an example, the train composition number and other variables are included in the variables of a calculation formula stored in the wireless network ID acquisition unit 22, and a wireless network ID is generated each time it is needed.
[0020] The train 4 includes a plurality of cars. Therefore, in the case where Wi-Fi (registered trademark) wireless communication is performed, for example, when the maintenance communication device is installed in the cab of the lead car 4a alone, radio waves may not reach the cab of the last car 4b. Thus, as illustrated in FIGS. 1 and 2,

the maintenance communication devices are installed in both of the cabs of the lead car and the last car, and use the same wireless network ID. In this case, the maintenance communication devices 2a and 2b must recognize that they are connected to the same train composition, and must share the corresponding wireless network ID to construct a wireless network. Therefore, the control transmission device 3a includes the wireless network ID transmission unit 33, and the maintenance communication device 2a includes the wireless network ID acquisition unit 22. The wireless network ID transmission unit 33 transmits the wireless network ID received by a wireless network ID reception unit 312 to the other control transmission device 3b mounted on the train 4 that is the same train composition.
[0021] When detecting the connection of the maintenance communication device 2a, the control transmission device 3a checks whether the wireless network ID reception unit 312 has already received a wireless network ID from the other control transmission device 3b. When the wireless network ID reception unit 312 has not received a wireless network ID, the wireless network ID generation unit 21 generates a wireless network ID and displays a readable image on the cab monitor. The wireless network ID transmission unit 33 transmits this wireless network ID to the control transmission device 3b. When the wireless network ID reception unit 312 has already received a wireless network ID, when the connection of the maintenance communication device 2a to the control transmission device 3a is detected, the wireless network ID acquired by the wireless network ID acquisition unit 22 is used to construct a wireless network. That is, the wireless network is constructed with the already received wireless network ID without activating the

wireless network ID generation unit 21. In this manner, between the maintenance communication devices connected to the separate cabs of the same train composition, a wireless network unique to the train composition can be constructed with the same wireless network ID. The notification of the train composition number is triggered by the connection of the maintenance communication device 2a to a port 36a of the control transmission device 3a.
[0022] As described above, in the case where Wi-Fi (registered trademark) wireless communication is performed, when the maintenance communication device is installed in the cab of the lead car 4a alone, radio waves may not reach the cab of the last car 4b. Specifically, suppose that the train 4 has ten cars. In this case, the total length of the train 4 is 200 to 300 m. The radio waves from the maintenance communication device installed in the first car, namely, the lead car, are estimated to reach up to the third car, and the radio waves from the maintenance communication device installed in the tenth car, namely, the last car, are estimated to reach up to the eighth car. Extension antennas can be installed in the fourth to seventh cars to deliver radio waves throughout the train 4, thereby enabling wireless communication.
[0023] The control transmission device 3a includes a new connection determination unit 31, a wireless network reading conversion unit 32, the wireless network ID transmission unit 33, a tablet response unit 34, a radio wave intensity determination unit 35, and the port 36a connectable by wire to an external terminal. Note that the control transmission device 3b differs from the control transmission device 3a only in that the control transmission device 3b includes a port 36b connectable by wire to an external terminal, instead of the port 36a.

[0024] The new connection determination unit 31 includes a train composition number notification unit 311 and the wireless network ID reception unit 312. The train composition number notification unit 311 stores the train composition number, and notifies the wireless network ID generation unit 21 of this train composition number when the control transmission device 3a and the maintenance communication device 2a are newly connected. The wireless network ID reception unit 312 receives the wireless network ID generated by the wireless network ID generation unit 21. [0025] The wireless network reading conversion unit 32 converts the wireless network ID received by the wireless network ID reception unit 312 into an image readable by a camera provided in the tablet terminal 1. The camera provided in the tablet terminal 1 reads this image, whereby the tablet terminal 1 is connected to the wireless network of the train composition to be subjected to maintenance. The image converted by the wireless network reading conversion unit 32 can be, for example, a one-dimensional or two-dimensional barcode. This image is displayed on the cab monitor screen (not illustrated) and read by the camera of the tablet terminal 1. Then, the tablet terminal 1 is connected to the wireless network to be used. Although the wireless network reading conversion unit 32 is not an essential component, the wireless network reading conversion unit 32 can facilitate the acquisition of the wireless network ID by the tablet terminal 1 in this manner. [0026] Note that the wireless network reading conversion unit 32 may convert the wireless network ID into a sound recognizable by the microphone of the tablet terminal 1. In this case, it is sufficient that the cab monitor (not illustrated) is configured to reproduce this sound when the screen of the cab monitor is manipulated. The wireless

network ID transmission unit 33 transmits the wireless network ID to the control transmission device 3b in the car 4b where the other cab is located.
[0027] The tablet response unit 34 includes a data transfer time measurement unit 341 and a history statistics management unit 342. The data transfer time measurement unit 341 measures the data transfer time for communication of a data request of a fixed size from the tablet terminal 1 to the control transmission device 3a. Such communication is performed at regular intervals between the tablet terminal 1 and the control transmission device 3a. The history statistics management unit 342 records the time for communication measured by the data transfer time measurement unit 341. The radio wave intensity determination unit 35 periodically inquires of the history statistics management unit 342 about the time for communication with the connected tablet terminal 1 based on a preset threshold value. When the time for communication is less than the threshold value, the radio wave intensity determination unit 35 outputs, to the maintenance communication device 2a, an instruction to disconnect from the wireless network, and terminates the connection to the tablet terminal 1.
[0028] A portable terminal represented by the tablet terminal tries to maintain the connection to the currently connected maintenance communication device even when the radio wave intensity is weak, and tries to establish a connection to another maintenance communication device once the currently connected maintenance communication device is disconnected. Therefore, even when the radio wave intensity is weak, the tablet terminal does not try to connect to a maintenance communication device with higher radio wave intensity unless the currently connected

maintenance communication device is completely disconnected. Consequently, a delay may occur in displaying a screen on the tablet terminal. According to the present embodiment, the tablet response unit 34 and the radio wave intensity determination unit 35 can select and connect to a maintenance communication device with higher radio wave intensity, thereby avoiding a delay in displaying a screen on the portable terminal. Although the tablet response unit 34 and the radio wave intensity determination unit 35 are not essential components, they can help the tablet terminal 1 connect to a maintenance communication device with higher radio wave intensity in this manner. Alternatively, connectable maintenance communication devices may be displayed on the screen of the tablet terminal 1 so that the user can select a maintenance communication device with higher radio wave intensity.
[0029] The tablet response unit 34 and the radio wave intensity determination unit 35 are not necessarily configured as illustrated in FIG. 2 and may be provided in the maintenance communication device 2a.
[0030] FIG. 3 is a flowchart illustrating the operation of the control transmission device 3a according to the embodiment. Specifically, FIG. 3 illustrates how the new connection determination unit 31, the wireless network reading conversion unit 32, and the wireless network ID transmission unit 33 operate. First, when the process is started, the new connection determination unit 31 starts waiting for a connection request from the maintenance communication device 2a (S1), and determines whether the maintenance communication device 2a has responded (S2).
[0031] When no response is received from the maintenance communication device 2a (S2: No), the new connection determination unit 31 continues waiting for a connection

request. When receiving a response from the maintenance communication device 2a (S2: Yes), the new connection determination unit 31 determines whether there is a wireless network ID already acquired (S3).
[0032] When there is a wireless network ID acquired (S3: Yes), the wireless network ID transmission unit 33 sends and transmits the acquired wireless network ID to the maintenance communication device 2a and the maintenance communication device 2b (S4). When there is no wireless network ID acquired (S3: No), the train composition number notification unit 311 of the new connection determination unit 31 sends the train composition number to the maintenance communication device 2a (S5). Then, the new connection determination unit 31 determines whether the maintenance communication device 2a has responded (S6).
[0033] When no response is received from the maintenance communication device 2a (S6: No), the train composition number notification unit 311 of the new connection determination unit 31 sends the train composition number again to the maintenance communication device 2a (S5). When receiving a response from the maintenance communication device 2a (S6: Yes), the wireless network ID reception unit 312 of the new connection determination unit 31 receives a wireless network ID (S7).
[0034] Then, the wireless network ID transmission unit 33 transmits the wireless network ID to the control transmission device 3b in the car 4b where the other cab is located (S8). After transmitting the wireless network ID, the new connection determination unit 31 starts waiting for a response from the maintenance communication device 2a
(S9). Then, the new connection determination unit 31 determines whether the maintenance communication device 2a has responded (S10). When receiving a response from the

maintenance communication device 2a (S10: Yes), the new connection determination unit 31 continues waiting for a response (S9). When no response is received from the maintenance communication device 2a (S10: No), the new connection determination unit 31 discards the wireless network ID held inside (S11) and ends the process.
[0035] FIG. 4 is a flowchart illustrating the operation of the maintenance communication device 2a according to the embodiment. Specifically, FIG. 4 illustrates operation of the wireless network ID generation unit 21 and the wireless network ID acquisition unit 22. First, when the process is started, the maintenance communication device 2a sends a connection request to the control transmission device 3a
(S21). Then, the maintenance communication device 2a determines whether the train composition number has been received (S22).
[0036] When the train composition number has been received (S22: Yes), the wireless network ID generation unit 21 generates a wireless network ID using the train composition number as a key (S23). Then, the maintenance communication device 2a constructs a wireless network with the generated wireless network ID (S24), and the wireless network ID generation unit 21 sends the generated wireless network ID to the control transmission device 3a (S25). When the train composition number has not been received
(S22: No), the wireless network ID acquisition unit 22 determines whether a wireless network ID has been received
(S26).
[0037] When a wireless network ID has not been received
(S26: No), the process returns to S21. When a wireless network ID has been received (S26: Yes), the maintenance communication device 2a connects to the wireless network which has already been constructed with the acquired

wireless network ID (S27). After sending the generated wireless network ID to the control transmission device 3a (S25) or after connecting to the wireless network having the acquired wireless network ID (S27), the maintenance communication device 2a starts waiting for a response from the control transmission device 3a (S28). The maintenance communication device 2a then determines whether the control transmission device 3a has responded (S29). [0038] When receiving a response from the control transmission device 3a (S29: Yes), the maintenance communication device 2a continues waiting for a response from the control transmission device 3a (S28). When no response is received from the control transmission device 3a (S29: No), the maintenance communication device 2a disconnects from the wireless network (S30) and ends the process.
[0039] FIG. 5 is a flowchart illustrating the operation of the control transmission device 3a according to the embodiment. Specifically, FIG. 5 illustrates an exemplar operation of the tablet response unit 34 and the radio wave intensity determination unit 35. First, when the process is started, the tablet response unit 34 starts waiting for a transmission control protocol (TCP) connection request (S41), and the tablet response unit 34 determines whether a request from the tablet terminal 1 has reached the control transmission device 3a via the maintenance communication device 2a (S42).
[0040] When no request is received from the tablet terminal 1 (S42: No), the tablet response unit 34 continues waiting for a TCP connection request. When receiving a request from the tablet terminal 1 (S42: Yes), the data transfer time measurement unit 341 of the tablet response unit 34 records the connection start time (S43). The

tablet response unit 34 starts waiting for a TCP disconnection request (S44), and determines whether a request from the tablet terminal 1 has reached the control transmission device 3a via the maintenance communication device 2a (S45).
[0041] When no request is received from the tablet terminal 1 (S45: No), the tablet response unit 34 continues waiting for a TCP disconnection request. When receiving a request from the tablet terminal 1 (S45: Yes), the data transfer time measurement unit 341 of the tablet response unit 34 records the connection end time (S46). Then, the tablet response unit 34 calculates the throughput based on the connection start time and the connection end time (S47), and stores the calculated throughput value in the history statistics management unit 342 of the tablet response unit 34 (S48). After that, the radio wave intensity determination unit 35 determines whether the calculated throughput value is less than a past throughput value set as the threshold value (S49). When the calculated throughput value is not less than the past throughput value set as the threshold value (S49: No), the current connection is to be maintained. Therefore, the process returns to S41. When the calculated throughput value is less than the past throughput value set as the threshold value (S49: Yes), the current connection is not to be maintained. Therefore, the radio wave intensity determination unit 35 causes the maintenance communication device 2a to disconnect the wireless communication with the tablet terminal (S50) and ends the process.
[0042] FIG. 6 is a diagram illustrating an example of the tablet terminal 1 according to the embodiment. The tablet terminal 1 illustrated in FIG. 6 includes a screen 1a and a button 1b. The screen 1a in FIG. 6 shows as an

example that the train 4 has five cars. FIG. 6 illustrates each of the cars constituting the train 4, the on/off state of indoor lights in each car, the on/off state of air conditioners in each car, the on/off state of blowers in each car, and the on/off state of on-board display devices in each car. The image on this screen is similar to the image displayed on the cab monitor. The word “similar” as used herein does not necessarily mean that the image on this screen is exactly the same as the image displayed on the cab monitor, but means that the image is shown such that the state of each instrument can be checked and manipulated through the displayed image. As illustrated in FIG. 6, on the screen 1a of the tablet terminal 1, an image similar to the image displayed on the cab monitor can be displayed. Therefore, an operator who performs maintenance work can check the screen displayed on the cab monitor with the tablet terminal 1 while visually monitoring the operation of instruments.
[0043] FIG. 7 is a diagram illustrating a general configuration of hardware that implements the maintenance communication devices 2a and 2b and the control transmission devices 3a and 3b illustrated in FIG. 2 in the embodiment. The hardware 40 illustrated in FIG. 7 includes a processor 41 and memory circuitry 42, which are connected to a bus. The processor 41 performs, by software, calculations and control using data obtained from the bus. The memory circuitry 42 stores data and the software that are necessary for the processor 41 to perform calculations and control. Such software can be, for example, a train maintenance communication program for operating the control transmission device and the maintenance communication device as described with reference to FIGS. 3 to 5. In a case where each of the maintenance communication devices 2a

and 2b is realized by the hardware 40, the processor 41 reads a calculation formula stored in the memory circuitry 42 and performs calculations based on the train composition number obtained from the bus to generate a wireless network ID. In a case where each of the control transmission devices 3a and 3b is realized by the hardware 40, the processor 41 outputs the train composition number, which is data stored in the memory circuitry 42, to the bus, and adds a destination to the wireless network ID, which is data acquired from the bus, for output to the bus. Note that an example of the hardware 40 is a computer.
[0044] According to the present embodiment described above, all the cars of the same train composition can use the same wireless network ID that is generated each time it is needed. Therefore, it is possible to prevent erroneous connection to wireless networks of adjacent pit tracks at a railyard. The prevention of erroneous connection to wireless networks of adjacent pit tracks enables simultaneous maintenance work at pit tracks adjacent to one another.
[0045] In the embodiment described above, the maintenance system including the control transmission devices and the maintenance communication devices has been described. However, the present invention is not limited to this, and the control transmission devices may include maintenance communication units that implement the maintenance communication devices.
[0046] The configuration described in the above-mentioned embodiment indicates an example of the contents of the present invention. The configuration can be combined with another well-known technique, and a part of the configuration can be omitted or changed in a range not departing from the gist of the present invention.

Reference Signs List
[0047] 1 tablet terminal; 1a screen; 1b button; 10 train maintenance system; 2a, 2b maintenance communication device; 21 wireless network ID generation unit; 22 wireless network ID acquisition unit; 3a, 3b control transmission device; 31 new connection determination unit; 311 train composition number notification unit; 312 wireless network ID reception unit; 32 wireless network reading conversion unit; 33 wireless network ID transmission unit; 34 tablet response unit; 341 data transfer time measurement unit; 342 history statistics management unit; 35 radio wave intensity determination unit; 36a, 36b port; 4 train; 4a, 4b car; 40 hardware; 41 processor; 42 memory circuitry; 5 wireless network.

WE CLAIM:
1. A control transmission device mounted on a train, the
control transmission device comprising:
a port connectable by wire to an external terminal;
a train composition number notification unit to provide notification of a train composition number of the train; and
a wireless network ID reception unit to receive a wireless network ID for constructing a wireless network, wherein
the wireless network ID received by the wireless network ID reception unit is generated based on the train composition number provided by the train composition number notification unit.
2. The control transmission device according to claim 1,
wherein
the notification of the train composition number is provided when the external terminal is connected to the port.
3. The control transmission device according to claim 1,
comprising
a wireless network ID transmission unit to transmit the wireless network ID received by the wireless network ID reception unit to another control transmission device mounted on the train of a same train composition.
4. The control transmission device according to any one
of claims 1 to 3, comprising, for wireless communication
over the wireless network:
a data transfer time measurement unit to measure a ratio between an amount of data communication and a

transfer time; and
a history statistics management unit to record a communication history provided by the data transfer time measurement unit.
5. The control transmission device according to claim 4,
comprising
a radio wave intensity determination unit to monitor the communication history recorded in the history statistics management unit, and determine whether the ratio measured by the data transfer time measurement unit is equal to or more than a preset threshold value.
6. The control transmission device according to any one
of claims 1 to 5, comprising
a wireless network reading conversion unit to convert the wireless network ID into an image readable by a camera or a sound recognizable by a microphone.
7. A maintenance communication device comprising:
a wireless network ID generation unit to receive a train composition number of a train and generate a wireless network ID using the received train composition number as a key; and
a wireless network ID acquisition unit to receive a wireless network ID generated externally.
8. The maintenance communication device according to
claim 7, wherein
for the wireless network ID, the wireless network ID generated by the wireless network ID generation unit or the wireless network ID acquired by the wireless network ID acquisition unit is used.

9. A train maintenance communication program for causing
a computer to execute:
a step of determining whether there is a wireless network ID of the train composition that is already acquired;
a step of constructing, when there is the wireless network ID of the train composition which is already acquired, a wireless network using the wireless network ID; and
a step of generating, when there is no wireless network ID of the train composition which is already acquired, a wireless network ID using a train composition number of the train as a key, and transmitting the wireless network ID to another cab.
10. A train maintenance system comprising:
a control transmission device mounted on a train, the control transmission device including a port connectable by wire and a train composition number notification unit to provide notification of a train composition number of the train; and
a maintenance communication device including a wireless network ID generation unit to receive the train composition number provided by the train composition number notification unit and generate a wireless network ID using the received train composition number as a key.
11. The train maintenance system according to claim 10,
wherein
the train composition number notification unit notifies the maintenance communication device of the train composition number when being connected to the maintenance

communication device.
12. The train maintenance system according to claim 11,
wherein
the control transmission device includes a wireless network ID reception unit to receive the wireless network ID generated by the wireless network ID generation unit.
13. The train maintenance system according to claim 12,
wherein
the control transmission device includes a wireless network ID transmission unit to transmit the wireless network ID received by the wireless network ID reception unit to another control transmission device mounted on the train of a same train composition.
14. The train maintenance system according to any one of
claims 10 to 13, wherein
the maintenance communication device includes a wireless network ID acquisition unit to receive a wireless network ID generated by another maintenance communication device connected to the another control transmission device.
15. The train maintenance system according to claim 14,
wherein
the maintenance communication device constructs a wireless network using the wireless network ID generated by the wireless network ID generation unit or the wireless network ID acquired by the wireless network ID acquisition unit to perform wireless communication.
16. The train maintenance system according to claim 15,
wherein

the control transmission device includes:
a data transfer time measurement unit to measure a ratio between an amount of data communication and a transfer time;
a history statistics management unit to record a communication history provided by the data transfer time measurement unit; and
a radio wave intensity determination unit to monitor the communication history recorded in the history statistics management unit, and determine whether the ratio measured by the data transfer time measurement unit is equal to or more than a preset threshold value.
17. The train maintenance system according to claim 16, wherein
the radio wave intensity determination unit outputs a command to disconnect the wireless communication to the maintenance communication device in response to determining that the ratio measured by the data transfer time measurement unit is less than the preset threshold value.