To ensure reliable and safe operation of the bridge structure throughout the life cycle, it is necessary to analyze and take into account many important factors, including the interaction of the main load-bearing structures. The presented work has new theoretical information, which gives the main provisions in the field of design of artificial structures for high-speed railroads. To analyze the system of a multi-span split bridge design using flexible intermediate supports of a flyover type, the Newton method (algorithm) is used. The basic data on the interaction of span structures and the design of flexible supports that are not taken into account in the design of facilities are not specified or regulated in the basic normative space, either by domestic JV standards or by foreign European EN standards, including national normative bases of the CIS countries. Harmonic analysis of the recording of the interaction of high-speed rolling stock and the joint operation of the main bridge structures of man-made structures is necessary for the design of high-speed railroads of transport infrastructure, especially in conditions of high-speed rolling stock. The article proposes a methodology for taking into account the interaction of the elements of the "bridge-train" system and determines the directions for further research to take into account the joint work and optimization of the basic designs of modern bridges and rolling stock in the region of high train speeds.