Journal of Physics: Conference Series

2131 (2021) 042096
IOP Publishing
doi:10.1088/1742-6596/2131/4/042096
3
2. Materials and methods 
The assessment of the reliability of the train radio communication network can be carried out using a 
complex indicator - the availability factor. Since the TRC network is a system consisting of many 
elements, then its readiness can be found, taking into account the availability factors of all elements of 
this system. These elements are: 
– command station (CS), 
– stationary radio stations (SRS), 
– portable radio stations (PRS), 
– wired channel (WC), 
– radio channel (RC). 
The listed elements of the PRS system correspond to the readiness factors: 
– equipment (SC – K
SC
, SRS – K
SRS
, PRS – K
PRS
); 
– wired communication channel – K
WC
; 
– radio channel – K
RC
. 
When assessing the availability factor of a wired communication channel, all failures are taken into 
account: conversion equipment, linear equipment, cable, power supply devices. 
The availability factor of a radio channel is determined by the radio coverage readiness – the 
probability that the signal level at the input of the receiver of a mobile radio station at a certain point 
of reception will be sufficient to ensure reliable radio communication. 
It is possible to organize communication channels of the following types between individual 
subscribers of PRS networks: 
1 – train driver-– train driver; 
2 – train driver– train station attendant; 
3 – train driver– train dispatcher; 
4 – train dispatcher – train station attendant. 
The most important and longest channel is the third type, that is, the communication channel 
between the train dispatcher and the train driver. It is used to control the movement of trains with 
guaranteed safety of train traffic. The structure of a communication channel of this type includes the 
largest number of elements in comparison with channels of other types. 
Since the elements of the train radio communication network, forming the channel between the 
train dispatcher and the train driver, are located sequentially, the value of the availability factor K of 
this channel will be determined by the product of the availability factors of all the network elements 
located sequentially: 
𝐾 = К
𝐶𝑆
⋅ К
𝑊𝐶
⋅ К
𝑆𝑅𝑆
⋅ К
𝑅𝐶
⋅ К
𝑃𝑅𝑆
The values of the readiness factors of individual elements of the PRS network can be either 
specified in the relevant regulatory documents, or estimated experimentally (according to statistical 
data, if any) or calculated theoretically. 
So, the availability factors of certain types of equipment - radio stations, command stations, can be 
determined on the basis of the MTBF prescribed in the documentation for the equipment, as well as 
the permissible recovery time. 
The availability factor of wired channels in railway communication networks, as a rule, has a very 
high standardized value. This is achieved, among other things, through the widespread use of technical 
diagnostics of the telecommunications network, multiple reservation of information transmission 
routes, the use of effective methods of protection against cyber attacks [8-15]. 
The availability of a radio channel, described by the coefficient of availability of the channel for 
radio coverage, can be found from the results of measurements of the dependence of the signal level at 
the input of the mobile radio station on the track coordinate, carried out using a laboratory car. 
The second method for determining the availability factor for radio coverage is a theoretical 
calculation, which can be performed using the industry-wide methodology for calculating the 
characteristics of a technological railway radio communication channel in force in Russia. 

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Intelligent Information Technology and Mathematical Modeling 2021 (IITMM 2021)
Journal of Physics: Conference Series
2131 (2021) 042096
IOP Publishing
doi:10.1088/1742-6596/2131/4/042096
4
A feature of train radio communication networks from the point of view of calculating the 
availability of communication channels is the dependence of the composition of the channel elements 
on the location of the mobile subscriber, that is, the mobile radio station. In this case, some of the 
elements - a command station, a wire channel (in the general case), a mobile radio station - remain 
unchanged elements with constant availability factors, and some of the elements - stationary radio 
stations, a radio channel, change during the movement of a mobile subscriber along the railway 
section (Figure 3). 
In other words, we can assume that when the mobile radio station moves along the railway section, 
the virtual key switches, sequentially creating a communication channel between the mobile radio 
station and each next stationary radio station located along the section.