Review article

The article considers the regularities of town-planning development from1900 to the beginning of 1941 of Saint-Petersburg-Petrograd-Leningrad and its agglomeration. Priority value of formation and improvement of transport and engineering infrastructure of the city and region in their spatial and functional interrelation referring to the indicated period is emphasized. On the basis of complex studying of contemporary archive records, stages of design options formation are studied, as well as multiple (for decades) accumulation of ideas concerning different spheres, such as town-planning, transport, and infrastructure. The sequence and possibilities of implementation of design offers are highlighted regarding the considered stage of region development. It is revealed that, despite the replacement of the imperial power with the Soviet power, Leningrad (called Petrograd till 1917) managed to keep the traditional line of spatial development considerably "crystallized" in the planning and transport-engineering infrastructure components. The latter, performing not only especially utilitarian functions, obtained a backbone status, defining the formation and preservation of the unique Saint-Petersburg town-planning code.