Development of proposals for adapting the existing methodology for calculating the available throughput to the operating conditions of the railways of Uzbekistan, taking into account the factors that ensure traffic safety when passing high-speed passenger trains. Methods: Grapho-analytical approaches and a comparative analysis method were used to determine the throughput of railway lines with mixed train traffic. Results: The main factors influencing the capacity of lines, advantages and disadvantages for each existing method for determining the capacity of railway lines are given. To assess the quality of transportation processes on railway lines, experimental train schedules were constructed. Based on the analysis of their indicators, a formula was proposed for calculating the throughput on double-track lines when passing high-speed passenger trains. Practical significance: The application of the proposed methodology improves the calculations of the performance indicators of sections with an unparalleled train schedule.