Analysis of industrial injuries and assessment of the risk of injury to railway power supply workers

. The purpose of this study is to analyze industrial injuries and assess the risk of injury to railway power supply workers based on mathematical statistics. It is shown that the level of injuries of this category of employees is at a significant level (the frequency coefficient of general injuries is higher by 2.6 times, and the frequency coefficient of fatal injuries is 5.7 times relative to the corresponding frequency coefficients in general for JSC “Russian Railways”). Based on the research results, the main causes of accidents with a fatal outcome were: poor organization and planning of work, violations of the technological process, violations in the use of personal protective equipment, lack of supervision on the part of the contractor, violation of work rules at the height, the extension of work place. The assessment of the risk of injury of contact network of electricians showed two possible types of accidents with them: electric shock and falling from a height. The probability of accidents is 0.031 and 0.051, respectively, with the number of injuries for each of the received scenarios on the five-year planning horizon being 7.85 and 12.75, respectively. The presented approach to assessing injury risks, supplemented by the method of expert assessments, will allow identifying and evaluating specific hazards at the workplace of linear level enterprises, respectively, to increase the effectiveness of developing of programs to improve working conditions and safety, and the effectiveness of implementing of tools for managing professional risks in order to reduce industrial injuries of employees of power supply divisions.


Introduction
One of the most traumatic industries is the electric power industry, which is characterized primarily by the risk of electric injuries for working personnel [1][2][3]. A similar situation is developing in the structural divisions of JSC "Russian Railways", which are engaged in the operation and repair of power supply systems and are among the most traumatic.
The introduction of a professional risk management system (PRMS) is one of the ways to reduce occupational injuries [4][5][6][7][8][9]. In railway transport, the company began to actively implement the PRMS through the modernization of the occupational safety management system in 2013, and in 2018, JSC "Russian Railways" adopted the Vision Zero concept of zero injuries [10,11], aimed at achieving the goal of zero injuries with a fatal outcome.
Despite the current trend of reducing accidents in power supply divisions -linear structural divisions of Transenergo -a branch of JSC "Russian Railways", 21 employees were injured in 2018, 6 of them fatally. 24 employees were injured in 2017, 6 of them were fatal.
The purpose of the study is to analyze industrial injuries and assess the risk of injury to railway power supply workers based on mathematical statistics.

Materials and methods
The object of research was the risk of injury to employees of power supply divisions. Currently, a significant number of risk assessment methods have been developed, including professional ones [12][13][14][15]. To assess the risks of injury, JSC "Russian Railways" has developed a Methodology for analyzing and evaluating professional risks for employees of JSC "Russian Railways", which allows calculating risks based on existing statistics of industrial injuries. The calculation was made as follows. At the first stage, statistics were collected on cases of occupational injuries for a given profession (table 1).
When referring to the sources of the activation of harmful and dangerous production factors (HDPF column 5 of table 1) the following symbols are used: I1 -the man himself, his labor, the means of labor; I2 -human interaction with technology and the environment; I3-interaction of people of different professions; I4-other. The following scenarios described the occurrence of injury (table 2).  The probability calculation for the i-th scenario is performed in two steps: Step 1. Calculation of the value of the parameter ̂. The parameter ̂ is calculated using the formula (1): where is the number of injuries in the i-th scenario; T-observation period (10 years); N -average number of employees per year (50 people).
Step 2. Calculation of the probability of injury occurrence in the i-th scenario.
Probability is calculated using the formula (2): The calculation results are presented in table 4.
The probable number of injuries per year for the i-th scenario is calculated using the formula (3): The probable number of injuries for 5 years in the i-th scenario is calculated using the formula (4): Results and discussion Table 5 shows the analysis of industrial injuries of employees of power supply divisions in the context of regional directorates of Transenergo -a branch of JSC "Russian Railways" for the period 2017-2018.
Of the 21 workers affected in 2018: 7 were injured by electric shock, 3 of them were fatal; 6 -as a result of falling from a height (including 1-fatally); 2-fatally injured as a result of the collapse of the structure; 2 -as a result of the impact of flying objects; 2-as a result of falling while moving, 1 -as a result of being beaten by third parties; 1 -as a result of hand pressure during loading of supports. The frequency coefficient (FC general) of injuries in Transenergo, which takes into account the average number of employees, for 2018 was 0.59, which is 2.36 times more than the frequency coefficient for JSC "Russian Railways" as a whole (0.25). The frequency coefficient of fatal injuries (FC fatal) in 2018 was 0.17, which is 5.7 times higher than the coefficient of JSC "Russian Railways" (0.03). The dynamics of the coefficient of frequency of industrial injuries is presented in table 6. The main types of industrial accidents that occurred in 2018 were mechanical and electrical injuries (table 7). The main types of the damaging factor of mechanical injuries (bruises, fractures, etc.) are given in table 8. The most traumatic positions and professions continue to be the electrician of the ECHK, ECHS (table 9). The largest number of workers affected in the production during the analyzed period had a work experience of more than 15 years (table 10), on the other hand, the age of the largest group of injured people is in the range from 21 to 30 years (table 11).  Based on the research results, the main causes of accidents with a fatal outcome were: poor organization and planning of work, violations of the technological process, violations in the use of personal protection equipment, lack of supervision on the part of the contractor, violation of work rules at the height of the extension place of work.
An analysis of the inspections revealed systemic weaknesses in the organization of work on labor protection: unsatisfactory performance requirements telegrams, protocols for occupational injuries, disorders in the design of operational-technical documentation, the power supply circuit, and partitioning, conduct formal monthly and quarterly monitoring of labor protection in linear units, the poor quality checking of outfits by the heads and specialists of energy divisions.
The results of the assessment of the risks of injury to employees of power supply divisions can be used to improve the targeting of corrective measures in the field of labor protection.
However, the presented approach to risk assessment has a number of limitations. Using historical data on industrial injuries allows you to assess risks only within the company's existing statistics (usually at the central or regional management levels). There is not enough data at the linear level. There are a significant number of linear enterprises with zero level of industrial injuries for 10 years or more.
This approach does not allow identifying and evaluating specific hazards in line-level workplaces.
In our opinion, it is possible to remove these restrictions by supplementing the approach presented above with the method of expert assessments. The working group formed in the structural division, using the methods of expert assessments, can analyze and assess the risks of specific technological processes and jobs at the linear level.

Conclusion
Industrial injuries of employees of railway power supply divisions remain at a fairly high level. A typical accident is an electrical or mechanical injury to a contact network electrician under the age of 30 or with more than 15 years of experience. The presented approach to assessing the risk of injury, supplemented by the method of expert assessments, makes it possible to increase the effectiveness of developing injury prevention programs by improving the system of labor protection management. The latter allows the occupational safety specialist to increase the effectiveness of implementing tools for managing occupational risks in order to reduce occupational injuries of employees at power supply divisions.