INCREMENT OF RAILWAY LINE CAPACITY

As amount of transportation increases capacity in some railway infrastructure places becomes insufficient. Usually increment of number of tracks in all or part of an overloaded line seems the most simple and clear solution. However investments into infrastructure are very large and expansion of infrastructure in populous territories may be impossible. Therefore all means enabling limitation or avoidance of infrastructure development or reconstruction have to be discussed. The main parameter influencing railway line capacity is difference in train speeds. Increasing the difference between the highest and the lowest train speed, feasible line capacity decreases. Reduction of the difference between train speeds enables increment of railway line capacity without changing infrastructure. A research estimating variables that determine commercial speed of trains and their importance is presented in the article. The commercial speed of trains depends on rolling stock traction and characteristics of breaking system, stoppage duration and some traffic control conditions. To decrease the difference between the train speeds the speed of the slowest trains has to be increased but the speed of the high speed trains must not be decreased. The freight trains and the passenger trains that stop in the intermediate stations very often are the slowest ones in the mixed traffic railway lines. Influence of different variables is evaluated using sensitivity analysis thus estimating potential increase in capacity. In the research examples of AB "Lietuvos gelezinkeliai" (SC "Lithuanian railways") infrastructure are used. After obtaining the results actions for increment of district capacity are suggested, without changing infrastructure parameters. The methodology assumes that the railway system consists of three main components: infrastructure, rolling stock and organizational traffic control means. When optimizing the railway transport system, interaction of the three components must be considered.