EVALUATION OF THE EFFICIENCY OF THE TRANSPORTATION OPERATION OF ELECTRIC LOCOMOTIVES ON THE FLAT SECTION OF THE RAILWAY

ABSTRACT

The results of the investigation of energy indicators of hauling electric locomotives hauling and kinematical parameters of the freight train movement on validation is given without stoping and with stoping on the virtual plain of railway district. The research results were obtained in the form of tabular data, graphical dependencies and regression equations designed to determine the main indicators of the transportation operation of electric traction locomotives on virtual and, identical to them, real flat sections of the railway and are recommended for implementation into the practice of specialists of the locomotive complex of the Uzbek railways.

АННОТАЦИЯ

Представлены результаты исследований по обоснованию энергетических показателей перевозочной работы локомотивов электрической тяги без остановок и с остановками на виртуальном равнинном участке железной дороги. Результаты исследований получены в виде табличных данных, графических зависимостей и уравнений регрессий, предназначенных для определения основных показателей перевозочной работы локомотивов электрической тяги на виртуальных и, идентичным им, реальных равнинных участках железной дороги и рекомендуются для внедрения в практику работы специалистов локомотивного комплекса узбекских железных дорог.

Keywords: investigation, result, the freight train, the electric locomotive, railway track, parameter, the stage, analysis, the station, time, speed, plain, virtual.

Ключевые слова: исследование, результат, грузовой поезд, электровоз, железнодорожный путь, параметр, разъезд, анализ, станция, время, скорость, равнинный, виртуальный.

Introduction

To ensure the efficient operation of railway transport, a high level of renewal of rolling stock fleets, modernization and strengthening of the infrastructure of related organizations, and development of the technical base for repair production are required.

To implement the above, it is necessary to conduct scientific research on the regulatory and methodological framework aimed at substantiating the parameters of the main indicators of operational readiness, reliability, safety and resource of traction rolling stock, taking into account the infrastructure of railway transport associated with the organization of the transportation process.

Increasing the capacity of electric railways (including Uzbek ones) can be achieved by increasing the volume of cargo and the number of passengers, as well as introducing promising resource-saving technologies into the work of railways. Therefore, it is very important to develop and use optimal modes of freight transportation, with economical consumption of energy resources for train traction and in compliance with the safety of train traffic. Optimization of freight transportation regimes will enhance the operational activities and capacity of electrified sections of railways.

Theoretical and experimental studies, which are carried out at the Department of Locomotives and Locomotive Economy of the Tashkent State Transport University, are aimed at substantiating the parameters of the movement of freight traffic, and at the rational use of electric locomotives.

Tasks and methods of research

The results of research work of foreign scientists Alekseeva T. L., Savoskin A.N., Elshibekov A. M., Cheremisina V. T., Natesan P., Bueno A. [6-10,13] ndoubtedly have scientific and practical value for the operation of rail transport. However, these works do not address the issues of substantiation of the kinematic parameters of the main energy indicators of freight traffic. In these works, there are no calculations of the efficiency of using electric locomotives in the territory of Uzbekistan.

Calculations must be made for different types and for different structures of cargo, on different sections of the route in terms of complexity. There are four types of track profile [1]: flat, hilly, hilly-mountainous and mountainous, which affect the traction quality of freight traffic. The purpose of the study is a theoretical substantiation of the energy efficiency indicators of the use of freight electric locomotives of the VL80^S series on a flat section of the track.

The calculations presented in the article are a logical continuation of the studies of one of the authors of this article [2-4].  Therefore, the already existing methods [9, 11] of the theory of locomotive traction were taken as the basis of the research algorithm. The material and technological conditions of freight traffic on a straight section of the track are taken from statistical data [2,5]. The object of study is electric locomotives of the 3VL80^S series of various weights, and a straightened section of the railway.

The subject of the study is the main energy indicators of the 3VL80^S electric locomotive. Their effectiveness, in quantitative and monetary terms, on a given section of the path. The energy and performance indicators of the studied freight electric locomotive 3VL80^S, taking into account the design features, are given in detail in previous works by one of the authors of the article [8]. The characteristic of the straightened track profile of the flat section of the railway is given in [2,3].

Results and analysis of the study

Energy performance indicators of the use of a three-section electric locomotive 3VL80^S, on a flat area, depending on various transportation conditions, are given in Table. 1 (in quantitative and monetary terms). Calculations are given for movement without stops, and with stops, at intermediate stations. The index "*" (asterisk) indicates the cost of funds (the cost of electrical energy), including value added tax.

Table 1.

Indicators of the transportation work of electric locomotives 3VL80^S on a flat section of the railway track

The dynamics of the averaged values, kinematic parameters of the movement of freight trains, and the parameters of the energy indicators of the freight traffic of 3VL80^S electric locomotives, depending on the mass of the train (for two types of rail transportation), is shown in fig. 1 and fig. 2. The average values were taken in the range from Q₁ = 2500 t to Q₃ = 3500 t (the mass of a freight train), for two different types of traffic, as arithmetic mean values.

Figure 1. Averaged kinematic parameters of motion freight train on a flat section of the railway

Figure 2. Average еnergy еfficiency рarameters electric locomotives 3VL80^S on the flat section of the railway

The authors of the article analyzed the effectiveness of the use (quantitative and qualitative components) of the 3VL80^S electric locomotive, on a given, flat area, in the process of transporting various types of cargo. The obtained parameters were compared with similar values for a unified freight train.

The results of the traction calculation obtained by one of the authors of the article [10] and the data in Table 1 for a freight train with a unified mass Q₂=3000 t and a constant number of axles (m = 200) show the following results:

1. The average total train travel time is 0.492 h (0.572 h), a decrease in train mass by ∆Q = 500 t leads to a decrease in the total train travel time by 0.68 (0.58) percent, and with an increase in train mass by ∆Q = 500 t, an increase in this time by 1.35 (2.62) percent;
2. Technical speed of the train with a similar change the mass of the composition tends to increase and decrease within the same limits, and, on average, it is equal to 89.50 (76.64) km / h;
3. The average train travel time for acceleration - deceleration is 0.0283 h, a decrease in the mass of the train by ∆Q = 500t leads to a decrease in the time for deceleration by 1.76 percent, and the time for acceleration remains unchanged with an increase in the mass of the train by ∆Q = 500t the time of the train to accelerate - deceleration increases by 8.82 percent;
4. The total and specific average consumption of electric energy for train traction is 2306.11 (2603.71) kWh and 17.74 (19.88) Wh/t km, respectively. The total and specific average costs of electric energy correspond, respectively, to 200723 (226684) soums and 4551.5 (5136.6) soums - excluding VAT and 240757 (271828) soums and 5459.3 (6164.9) soums - including VAT;
5. An increase in the mass of the composition by ∆Q = 500 tons contributes to an increase in the total consumption of electricity by 10.24 (7.86) percent, however, the specific consumption of electricity in this case decreases by 3.45 (7.52) percent, and a decrease in the mass of the composition by ∆Q = 500t provides a reduction in the total and an increase in the specific consumption of electricity, respectively, by 4.35 (7.72) and 14.80 (10.73) percent;
6. Reducing the mass of the composition by ∆Q = 500t leads to a decrease in the total and specific cost by an average of 4.35 (7.72) percent, and with an increase in the mass of the composition by ∆Q = 500t, these indicators increase by an average of 10.24 (7.86) percent;
7. Reducing the mass of the train by ∆Q = 500t leads to a decrease and an increase in the use of traction modes [1], as well as idling and braking [2], respectively, by 2.67 (3.05) percent, and with an increase in the mass of the composition by ∆Q = 500 tons, on the contrary, there is an increase and decrease in these indicators by 5.57 (1.83) percent;
8. The travel time of the train in the idling and braking mode, as well as in the traction mode, varies, respectively, from 0.245 h (0.266 h) to 0.178 h (0.246 h) and from 0.273 h (0.302 h) to 0.32 h (0.341 h). With an increase in the mass of the train by ∆Q = 500t, there is a decrease in the travel time of the train in the idling and braking modes, as well as its increase in the traction mode, respectively, by 0.025 h (0.004 h) and 0.032 h (0.019 h). The travel time of the train in the idling and braking mode increases, and in the traction mode it decreases by 0.015 h (0.016 h) and 0.015 h (0.019 h), respectively, with a decrease by ∆Q = 500 tons of the mass of the train.

Values in parentheses are for traffic conditions with stops at an intermediate station.

Based on the results of the calculations, graphs of the parameters of the main indicators of freight transportation of 3VL80^S electric locomotives on the flat section of the railway were built. According to the graphs, you can calculate the value for any i - th mass Q of a freight train (in brackets - traffic conditions with a stop at an intermediate station). In formulas (1) - (10) it was obtained: R² = 1.0 - a sufficient value of the approximation reliability (the necessary reliability condition is R²≥0.8). An asterisk "*" - movement with stops at an intermediate station. Sign two asterisks "**" - movement taking into account value added tax (VAT). The value of Q_i = 1,2,3 is an indicator of the traction calculation option.

Technical speed of the train V_т, km/h

V_т = –0,295 Q_i² + 0,275 Q_i + 90,33 ∕ V_т^* = – 0,755 Q_i² + 1,805Q_i + 76,55     (1)

Total train travel time t_x, min

t_x = 0,1Q_i² – 0,1Q_i + 29,3 ∕ t_x^* = 0,35 Q_i² – 0,85Q_i + 34,6                  (2)

Train travel time in traction mode t_т, min

t_т = 0,5Q_i² – 0,6 Q_i + 16,5 ∕ t_т^* = 1,15Q_i² – 0,7Q_i + 17,0              (3)

Train running time at idle and braking modes t_хх,т, min

t_хх,т = – 0,4Q_i² + 0,5Q_i + 12,8 ∕ t_хх,т^* =  0,35Q_i² – 2Q_i + 17,6           (4)

Total electricity consumption per trip A, kWh

А = 66,655,6Q_i² – 101,62Q_i +2198,3 ∕ А^* = 1,82Q_i² + 195,53Q_i +2204,2         (5)

Specific electricity consumption per trip a, Wh/tkm gross

а = 0,97Q_i² – 5,44Q_i + 24,09 ∕ а^* = 0,315Q_i² – 3,055Q_i + 24,52           (6)

Total cash costs of С_Э, sum

С_Э = 5801Q_i² – 8842Q_i + 191336 ∕ С_э* = 152,5Q_i² + 17038Q_i + 191837        (7)

Total cash costs С**_Э including VAT, som/km

С**_Э = 6959Q_i ² – 10609Q_i + 229500 ∕ С_Э** = 190Q_i² + 20413Q_i + 230115*  (8)

Reduced monetary costs of с_Э, som/km

с_Э = 131,6Q_i² – 200,7Q_i + 4338,8 ∕ с_Э^* = 10,3Q_i² + 359Q_i + 4370,5           (9)

Reduced cash costs ce** including с_э**, som/km

с_э** = 157,85Q_i² – 240,75Q_i + 5204,3 ∕ с_Э** = 4,3Q_i² + 462,9Q_i + 5218**    (10)

It follows from the analysis of the equations that the dynamics of parameters, the dependence of the change in the mass of a freight train is described by a polynomial of the second degree. The exception is the travel time of the train, in traction mode, with a stop at an intermediate station (linear dependence).

The authors of the article studied various conditions for organizing the movement of freight trains. Regression equations are obtained, and the numerical values of the parameters of the main indicators of transportation work, and the efficiency of the use of electric locomotives 3VL80^S, on the flat section of the railway are substantiated. The following conclusions can be drawn:

• It follows from the analysis of the equations that the dynamics of parameters, the dependence of the change in the mass of a freight train is described by a polynomial of the second degree;

• The exception is the travel time of the train, in traction mode, with a stop at an intermediate station (linear dependence);
• The consumption of electrical energy spent on the movement of the 3VL80^S electric locomotive directly depends on the operating time of power energy systems, that is, in the traction mode, the reduction of which will lead to a decrease in the mechanical operation of the electric locomotive and will reduce the consumption of electrical energy;
• The consumption of electrical energy spent on deceleration - acceleration, at each stop of a freight train at an intermediate station or a separate point, ranges from 119.1 kWh / ost (Q₁ = 2500t) to 156.9 kWh / ost (Q₃ = 3500t ), and on average it is 148.8 kWh/rest;
• An increase in the volume of transportation work by 3VL80^S electric locomotives contributes to an increase in the efficiency of using these electric locomotives, in operating conditions, regardless of the type of freight train traffic.

As a result of the research, the authors of the article substantiated the kinematic parameters of the movement of freight trains and the parameters of the energy efficiency indicators of 3VL80^S electric locomotives in the form of tables and graphs. Regression equations have been obtained to determine the main indicators of the transportation work of the studied electric traction locomotives on virtual and, identical to them, real flat sections of the railway.

Conclusion

The obtained result of the research is logically consistent with the research [7-10,13]. They can be applied in practice, when evaluating the efficiency of traction and energy characteristics of electric traction locomotives on flat areas. The results of the study are recommended for implementation on the Uzbek railway.

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