The purpose of the study is to investigate the primary reasons for the feasibility of the combined movement of high-speed passenger and freight trains. The research includes the analysis and theoretical synthesis of materials related to the combined movement of high-speed passenger and freight trains in European Union countries. The combination of different train categories on high-speed rail lines is not only possible but also, under certain conditions, advisable. The main reasons for arranging sections of combined passenger and freight movement include overcoming contour or height obstacles and justifying investments in the construction of high-speed railways where the demand for passenger transportation is insufficient and profitability is ensured through additional income from cargo transportation. The combined movement of high-speed passenger and freight trains can reduce environmental impact by ensuring the efficient use of railway infrastructure and decreasing transport emissions. The authors have proposed a comprehensive approach to assessing the effectiveness of implementing the movement of high-speed passenger and accelerated freight trains, considering the net present value and ensuring the capacity of the double-track railway line during concurrent train movements. The research results enable enhancing the stability of railway transportation on high-speed railways.