OPERATIONAL DISTRIBUTION OF THE TRAIN TRAFFIC VOLUME ON THE SECTIONS OF RAILWAY OPERATING DOMAIN Purpose

Purpose. The task of the operational distribution of train traffic volume on the sections of operating domain is the optimization one. It is solved in the operational conditions by the dispatch station. The article sets the problem of formalizing and finding the new ways to solve this urgent problem. Methodology. A new approach to solving the problem of operational distribution of train traffic volume on the sections of the rail network with a choice of routes for all train traffics was proposed. Findings. A study of possible routes for the train traffic handle on the operating domain used for mass freight transportations between Krivyi Rih and Donbas was carried out. The use of the proposed method allowed us to obtain a rational distribution of trains on the rail network sections. Originality. The method of train traffic volume distribution in the network under operational conditions was improved. The method, as opposed to the current one allows one to select the route of separate units handle (according to the criteria of the weighted average cost for 1 ton of cargo). Practical value. The use of the proposed technology of the operational distribution of train traffic volume will increase the efficiency of the railways in general and ensure the competitiveness of rail transportations. The methodology implementation involves the use of railway dispatch station for the automated workplaces with appropriate informational support.


Introduction
Formation of profitable mechanism in the field of freight transportation in the conditions of transport market functioning involves minimizing of their costs.This requires the development of both new technologies and new approaches to the organization of the train traffic volume, operational management improvement [2,7].Selection problem of the rational traffic volume distribution over the network sections is the optimization one.A considerable number of scientific papers is devoted to its solution.[1,5,6,9,10].The scientists solved this problem in the conditions of motion in the network of indivisible elements (liquid, gas, etc.) and separate units of the traffic volume (trains, cars).Other papers propose the solution of this problem in the conditions of owner interest of separate network sections.
General distribution of train traffic volume over railway domain can be implemented according to the criterion of total profits of railways and it can be directed to the railway profitability increase.But in the conditions of constant change of train situations in the domain sections the obtained distribution may be ineffective.That is why train dispatchers have to correct it in conditions of operational change of train situation and to determine the rational routes for train handling according to additional selection criteria.

Purpose
The purpose of the article is the search for new approach concerning solution of the urgent problem of operational distribution of train traffic volume over the sections of railway network with a choice of routes for all traffic units.

Methodology
The weighted average cost of 1 ton of cargo in the freight train set is proposed to use as the selection criterion.This criterion can ensure handle of more valuable cargo weight on the fastest routes.This allows the increase of cargo turnover at the sections and speed up the movement of circulating assets of cargo owners.
Each cargo owner tends to accelerate the turnover of their funds by the reduction of procurement time, manufacturing of cargo transportation and sales, so the delivery speed of cargo is very important in the period of its life cycle.
where A -is a daily train traffic in one direction of the given cargo type, weight; q -is the average loading of the car on the direction, tn; т c -is a weighted average cost for the one ton of cargo, grn; ст d -is a discount rate; дост t -is the average time of cargo when moving from the dispatch station to the destination one.The weighted average cost of one ton of cargo is determined using the formula [5]: where j -is a cargo type; j α -is a cargo share of the j type from the total cargo volume in the train; вантj c -is an average cost of the j cargo.

Findings
The operating domain connecting the industrial regions of Kryvyi Rih and Donbas is the research object.The Fig. 1 shows the network sections that can be used for train handling.Each section is described by the length parameters and the number of trains running in the doubled and nonpaired directions.
For the operating domain the structure of cargo volume was analyzed, the costs for each cargo type and the general traffic volumes with the distribution according to the cargo type was determined [3].On the basis of the obtained data the weighted average cost for 1 tn of cargo in the particular train was determined.It is equal в 3 020 C = grn/tn.In addition to solve the problem the daily cargo volume according to the cargo type and the term of train running in the particular route were determined.Results of expense calculations for customers of cargo in motion depending on handle routes are shown in Fig. 2.
Analysis of the calculations shows that the cargo cost has quite a significant impact on costs of cargo owners.Reduce in transportation term by 1-3 hours may cost cargo owners several thousand UAH excluding the expenses for rolling stock.For the railway, in turn, it is more profitable to retain customers, transporting cargo of great cost because the rates for transporting are proportional to the cost.So it is recommended to pass the trains with more expensive cargo by the shortest routes.

Originality and Practical Value
The method of train traffic volume distribution in the network in operational conditions was improved.As opposed to the existing ones it allows choosing a route for handle of separate units of traffic volume according to the criterion of 1 ton of weighted average cost of the cargo in train set.when the problem arises, dispatchers are governed by regulatory documents (Plan for Train Formation, Schedule of train movement, etc.), which can not account all the changes of the train situation on the handle routes.First of all this affects the reduction of operation performance and the level of railway profitability.When the problem of distribution can not be solved by recommendations of regulatory documents, dispatcher takes operational decision on train distribution based on his own experience, but not always it gives maximal results.
As for the rationalization of freight trains handle it is proposed to take into account such criterion as the weighted average cost for 1 ton of cargo in the train and the load capacity of handle route sections.That is, when the problem of the separate train handling arises, the possible routes of the train running between stations of departure and destination are determined.The period of train running for each route is estimated using a model of railway domain or its separate directions [4, 8, 11, 12 13], load capacity of the section and weighted average cost for 1 ton of cargo in the train.This should provide the appropriate software equipment for AWM (automated work place) of dispatcher.According to these criteria, trains with more expensive cargo are departed by the shortest routes considering the load capacity of route sections.Research shows that with the load capacity of the shortest route section of 85% and up, it is excluded from the priority variants and can be used in accordance with appropriate load capacity of all other routes only.
For the railway domain between the stations Kryvyi Rih Sortuvalnyi -Yasynuvata the main routes of freight trains running and the total period of running for a separate train with standard loading of sections, as well as the total operating costs for one train handle on the routes of running were determined.
Graphical comparison of routes is presented in Fig. 3.
Based on the obtained dependencies, one can conclude that it is reasonable to handle the trains with more expensive cargo on routes 2 and 3.Although they are not the shortest and the fastest the total operating costs are much lower than the faster routes 6 and 7.The train handle on routes 1, 4 and 5, which differ by significant cost and long period of transportation is not reasonable at all.First of all it is caused by the fact that the sections with diesel locomotive traction are included into the route.Therefore, one should handle the trains with relatively low weighted average cost for 1 ton of cargo in the train on these routes.These routes should only be used when the other ones are loaded.The general distribution of train traffic volume on the domain sections is presented on Fig. 4.

Fig. 1 .
Fig. 1.General structure of operating domain and amount of freight train traffic according to directions

Fig. 3 .
Fig. 3. Comparison of the possible routes for traffic volume handle in the domain: a -total lengthes of routes in the domain; b -time histograms of the freight trains depending on the routes of running; c -histogram of operating costs for one train handle depending on the routes of runningTaking into account the multiple circuit of railways and a large number of variants for handle of the particular train, the train and road dispatchers should cope with the task of determining the optimal route for a separate train and improvement of general operation performance of the domain sections.Most often,

Fig. 4 .
Fig. 4. Rational distribution of train traffic volume on domain.а/c -distributed number of freight trains / maximum number of freight trains, which can be handled on the section including technical equipment and volumes of passenger trains traffic Prof. V. I. Bobrovskiy, D. Sc. (Tech); Prof. Ye. S. Aleshynskiy, D. Sc. (Tech) recommended this article to be published