Logistic indicators of locomotives of diesel traction in Marokand-Kattakurgan section of Uzbek railway

. The results of a study on the substantiation of the parameters of the logistical indicators of rail freight traffic implemented by diesel locomotives of the UzTE16 M 3 series when moving with stops on the hilly-mountainous section of Marokand - Kattakurgan of the Uzbek railway are presented. The research methodology is a graphical method for solving the differential equation of train movement in the accepted range of changes in the mass of the composition of freight trains as a result of the implementation of which the authors obtained complete and reduced kinematic parameters of the movement of freight trains per one kilometer of the railway track and the parameters of the logistic indicators of the energy efficiency of these diesel locomotives in the form of tabular data, graphical dependencies, as well as regression equations with the subsequent development of nomograms for their calculation. The results of the study can be used by specialists of the Bukhara locomotive depot, which will allow them to develop recommendations for saving diesel fuel by the diesel locomotives under study, considering various conditions for organizing rail transportation of goods.


Introduction
At present, «Uzbekiston Temir Yullari» JSC is carrying out widespread intensive electrification of Uzbek railways [1,2], approximately 90% of the total length of sections of which will already be electrified by 2030 and, in this regard, is actively replenishing the operating fleet of electric traction locomotives due to passenger and freight, passenger and cargo Chinese electric locomotives of the new generation «Uzbekistan».
Moreover, the demand for locomotives of diesel traction does not weaken.Still, it continues to remain at a fairly high level, including, first of all, this applies to three-section mainline (train) freight diesel locomotives of the UzTE16M3 series [2], which account for approximately 30 percent of the total operating fleet of locomotives of diesel traction of «Uzbekiston Temir Yullari» JSC.
Studies on the justification, analysis, and evaluation of the effectiveness of the use of these diesel locomotives in real operating conditions on sections of the Uzbek railways of different degrees of complexity, taking into account the main indicators of transport the author [26,27] shows that these works did not consider the issues of substantiating the main logistical indicators of transport logistics, such as the technical speed and travel time of freight trains at different operating modes of the diesel generator set, the amount of natural diesel fuel consumption for train traction in quantitative and monetary terms, and their impact on the energy efficiency of the use of traction rolling stock, including diesel, on the sections of Uzbek railways, was not assessed, taking into account the degree of complexity their profile railway track.In addition, these studies do not reflect the issues of substantiating the logistics indicators that characterize the stopping process of the movement of freight trains and the transportation work of diesel traction locomotives in real operating conditions.

Objects and methods of research
The present research continues the work [2,3] and is devoted to the study of the conditions of transportation operation of three-section mainline (train) freight diesel locomotives of the UzTE16M3 series during the movement of freight trains with stops at separate points in real operating conditions on a given (accepted by the authors) real section Marokand -Kattakurgan of the Uzbek Railway.
The purpose of this study is to substantiate the indicators of the transport logistics of the movement of freight trains and the logistics indicators of the transportation work of diesel traction locomotives in quantitative and monetary terms on a real, hilly-mountainous section of the Uzbek Railway.
To implement this study, the authors performed a series of traction and energy calculations based on the corresponding algorithm for performing traction calculations developed by the author [26], initial data, methods of the theory of locomotive traction, and the object and subject of research [1,27].
The object of the study is freight trains with different masses of trains and three-section mainline (train) freight diesel locomotives of the UzTE16M3 series, as well as the hilly and mountainous section of the Marokand -Kattakurgan of the Uzbek railway.
The subject of the study is the logistic indicators of the transport logistics of the movement of freight trains with the organization of stops at intermediate stations and the main logistic indicators of the energy efficiency of using the diesel locomotives under study on the hilly-mountainous section of the railway in quantitative and cost (monetary) terms.
The design of diesel locomotives of the UzTE16M3 series, their traction and energy characteristics are covered in [27], and the parameters of the straightened track profile of the hilly-mountainous section of Marokanda -Kattakurgan are given in the study [1].

Results and their discussion
The main indicators of the transport logistics of the movement of freight trains and the transportation work of diesel locomotives of the UzTE16M3 series during the movement of freight trains with stops at the Marokand -Kattakurgan section of the Uzbek railway are shown in Table 1.Also, this table shows the average and, taking into account studies [28], the average values of the parameters of the above indicators for two types of traffic (with stops and without stops at intermediate stations), and the latter were calculated as arithmetic averages in the accepted range of changes in the mass of compositions of freight trains.The methodology for evaluating the effectiveness of the studied UzTE16M3 diesel locomotives carried out in the implementation of rail transportation of different ways and types of cargo in freight movement on a given, high-speed railway section Marokand -Kattakurgan provided for a comparison between themselves of the average and averaged values of the above-mentioned indicators of transport logistics.Analysis of the average values of the main kinematic and energy indicators of transport logistics of the accepted object of study, taking into account the values for both types of movement in real operating conditions, allows us to draw the following conclusions: -the magnitude of the change in the speed of movement and consumption of diesel fuel, which are the main indicators of the transport logistics of the transportation process, depends on the type of movement of freight trains and does not depend on the composition and structure of the transported cargo; -the amount of diesel fuel consumed by the diesel locomotive under study directly depends on the duration of the diesel generator set under load; -operation of the diesel engine at idle helps to reduce the amount of diesel fuel consumed by the diesel locomotive under study in the route of the rolling stock; -the amount and cost of consumed diesel fuel are reduced with a decrease in the mass of the freight train; -an increase in the mechanical work of forces acting on a freight train occurs with an increase in the operating time of the investigated diesel locomotive in the mode traction and the composition mass of the freight train; -the mechanical work of forces on freight trains increase with decreases in the operating time of the diesel generator set of the diesel locomotive under study in modes idling; -improving the efficiency of rail freight transportation directly depends on the increase in the volume of transportation work performed by the studied diesel locomotives and the load on the axles of wheelsets of freight trains and does not depend on the composition and structure of the transported cargo, as well as of the type of freight train traffic; -each decrease in the number of wagons in a freight train contributes to an increase in the specific consumption of diesel fuel for train traction and a decrease in cash costs for rail transportation of goods; -the total and specific cost of freight rail transportation increases with an increase in the mass of freight trains.
Similarly to studies [2,3,27], by processing in the Microsoft Excel Office environment the values of the above indicators of transport logistics of movement of freight trains by diesel locomotives UzTE16M3, regression equations were obtained to calculate their values for real conditions organizing of freight traffic with stops with a sufficient value of the approximation reliability R 2 = 1.0 for each i -th mass of the composition Qi of a freight train on the section Marokand -Kattakurgan of the Uzbek railway.Total train travel time tt tr, min: Train travel time in mode traction ttr, min: Train running time at idle and braking modes tid.,br, min: tid,br = -0.625QiSpecific consumption of conventional diesel fuel еsp, kg / 10 4 t km brutto: еsp = 0.875Qi 2 + 0.345Qi + 31.09(7) Total cash costs Сd.f, thousand soums: Specific cash costs сt, thousand soums / km: Analytical dependencies (1) -( 9) are in good agreement with the studies [2,3,27,28] and confirm that the parameters of the main indicators of transport logistics during the movement of the studied diesel locomotives UzTE16M3 with stops on section Marokand -Kattakurgan of "O'zbekiston temir yo'llari» JSC with a change in the compositions mass of a freight train are described by a polynomial of the second degree.
The kinematic parameters of the transport logistics of the movement of a freight train with stops at intermediate separate points and the logistic indicators of the efficiency of the transportation work of three-section mainline (train) diesel locomotives UzTE16M3 with a specific uniform distribution of their values for each stop at an intermediate station are given in table 2.
In Table 2 the negative sign (minus) predetermines only the reduction (decrease) in the technical speed of movement of the freight train in the process of decreasing the mass of composition of the train and nothing more; that is, this sign characterizes only a decrease in the value of the main indicator of the mentioned transportation work and does not affect the absolute values of the technical speed of movement.The averages in said Table 2 were calculated as arithmetic average values.Fig. 1 and Fig. 2 show the dynamics of changes in the indicators of transport logistics of the movement of a freight train with different masses of trains and energy efficiency of the use of diesel locomotives UzTE16M3 on the hilly-mountainous section Marokand -Kattakurgan of the Samarkand -Navoi -Bukhara railway line of "O'zbekiston temir yo'llari" JSC depending on the load on the axles of the wheel sets of the train, taking into account its reduction.
The above parameters of logistic indicators were determined for one stop of a freight train; however, for a more "visual" image in Fig. 2, the values of the total and specific consumption of full-scale diesel fuel, as well as of the reduced cash costs, were increased, respectively, by two, four and one and a half times.
In addition, for one stop of a freight train at an intermediate station, a siding, or a separate point, we have the following data‫׃‬ -the value of the total and specific consumption of natural diesel fuel is, respectively, 36.423kg and 2.357 kg/10 4 t km gross (Q1 = 2500 t), 39.917 kg and 2.153 kg/10 4 t km gross (Q2 = 3000 t) and 41.187 kg and 1.907 kg/10 4 t km gross (Q3 = 3500 t); -the average value of the total (full) and specific consumption of full-scale diesel fuel for train traction per one kilometer of the railway track is approximately 2.33 kg/km and 0.151 kg / 10 4 t km gross: km (Q1 = 2500 t); 2.47 kg/km and 0.133 kg/10 4 t km gross: km (Q2 = 3000 t) and 2.64 kg/km and 0.122 kg/10 4 t km gross: km (Q3 = 3500 t).
-the average value of the reduced cash costs (expenses) for train traction per one kilometer of the railway track is approximately 4.128 thousand soums/km (Q1 = 2500 tons); The results obtained by the authors of this stage of the research showed a fairly high convergence and are in good agreement with the research data [2, 3, 27, 28, etc.]; therefore, they can be used in assessing the fuel-energy efficiency of locomotives of diesel traction on real hilly-mountainous sections of the railway track.

Conclusion
1.As a result of the modernization of the diesel generator set of diesel locomotives UzTE16M3 by replacing the diesel engine 10D100 of diesel locomotives 3TE10M with diesel 5D49, taking into account new auxiliary diesel systems, were obtained traction and energy characteristics and traction properties of these of the diesel locomotives modernized of a higher level and quality, ensuring their normal operation on sections of the Uzbek railways of varying degrees of difficulty, including hilly -mountainous.2. Within the range of changes in the mass of the freight train composition accepted by the authors with a constant number of axles in the composition, the logistic indicators of the movement of freight trains and the transportation work of the investigated diesel locomotives UzTE16M3 along the route on the real, hilly-mountainous section Marokand -Kattakurgan of the Uzbek railway were obtained.3. It is proved that the dynamics of changes in the above logistic indicators depending on the composition mass of the freight train is described by a polynomial of the second degree, and the regression equations obtained by the authors to determine their numerical values will allow us to correct systemic measures and identify further ways to economically use full-scale diesel fuel for train traction for linear enterprises of the locomotive complex "Uzbekiston temir yo'llari" JSC. 4. The research results obtained by the authors are recommended for practical use by specialists in the locomotive economy related to the issues of substantiating differentiated consumption rates of fuel and energy resources for train traction.

Fig. 1 .
Fig. 1.Indicators of transport logistics of movement of freight train on section Marokand -Kattakurgan: ∆Vt is technical speed of movement; train running time -general ∆tt tr, in traction mode ∆ttr, in idling and braking mode ∆tid br

Table 1 .
Indicators of transport logistics of diesel locomotives UzTE16M3 on high-speed section

Table 2 .
Main indicators of transport logistics of freight trains on section Marokand -Kattakurgan,