The study is devoted to the history of the design and construction of the Baikal-Amur Mainline, its significance for the economy, politics and defense of the country. The authors provide a historical overview of the topic under study, present various points of view on the construction of the project at different stages of the socio-political and economic development of the state in the 19th century, the 1930s–1950s, and during the period of the beginning of the construction of the BAM in the 1970s. The highway, originally designed as a backup for the Trans-Siberian Railway, had established itself as a powerful domestic defense project by the time construction began. During the period of the beginning of operation and until the 2000s, the highway was considered a low-traffic line. However, in recent years, the BAM project has become a powerful locomotive for the development of the east of the country and all of Russia as a whole. Along with the development of the extractive industries in the areas of gravity of the highway, the BAM is becoming the largest transit corridor in Eurasia. Currently, there is a "turn in the vector of the country's development to the East." However, a major problem in the development of the entire Eastern transport polygon as a whole and the BAM in particular is the weak development of the transport infrastructure compared to that in the European part of the country. The paper discusses the progress of strengthening the project under consideration (construction of additional artificial structures, second tracks, extension of station tracks, electrification along the entire length, etc.), prospects for further development of the highway in the near and distant future, including for increasing the connectivity of the territory of Russia. Today, BAM is understood as a large-scale railway development project - a latitudinal element of the transport grid of Siberia and the Russian Far East, the construction of which is a strategic goal of the country in the long term. BAM is being transformed from an auxiliary line into a truly instrument for the country's survival in a hybrid war with the collective West.