The development of railway transport in Ukraine is associated with the improvement of transportation along the routes of pan-European transport corridors, improving rail connections with the countries of the European Union and domestic transportation. This requires the renewal of traction rolling stock, the current technical condition of which does not meet modern indicators of fuel efficiency and environmental friendliness. An analysis of traction rolling stock from world manufacturers shows the interest of railway operators in locomotives with dual-mode power supply. Such locomotives are able receive power both from the contact network and a diesel generator. This provides a number of advantages, the key among which is a reduction in the cost and transportation duration. The designs of ALP-45DP locomotives manufactured by Bombardier Transportation, Vectron Dual Mode manufactured by Siemens Mobility, EURODUAL and Class 93 manufactured by Stadler are considered. It’s demonstrated that locomotives with dual-mode power supply are based on the design and components of serial locomotives. This reduces the cost of the explored locomotives, simplifies maintenance and ensures high reliability. At the same time, the presence of dual-mode power supply has influenced the application of specific design and circuit solutions. Energy storage systems, including plug-in accumulators, are promising for use on locomotives with dual-mode power supply. The use of accumulators allows both to accumulate energy during braking and power the locomotive systems, and to store energy from low-cost sources. This reduces the cost of fuel and energy resources. Basing on the analysis fulfilled, the structure of the traction system for a domestic locomotive with dual-mode power supply, which can be created by modernizing existing locomotives, is proposed and substantiated.