The role of the Trans-Siberian main railway is considered related to interaction between the West and the East of Eurasia. The stages of formation of a transport-economic belt along the Trans-Siberian main railway and its branches are distinguished. The main features of long-term development of the Trans-Siberian main railway, its new branches, and also the Russian mega project "Integrated Eurasian infrastructural system" are presented. The comparative characteristic of a zone of influence of the Trans-Siberian main railway and a New Silk Road in the People's Republic of China is given. General environmental issues in the development of transcontinental Eurasian transport-economic belts are singled out. The authors believe that despite some competition to the Trans-Siberian Main Railway in the Eurasian transport transit, realization of the New Silk Road project will bring obvious socio- economic and environmental benefits for participating countries through formation of the zone of the sustainable development along this transport corridor. Finally, it will undoubtedly contribute to achievement of closer economic integration and greater security in Eurasia.