Russia is offering to build more railways into Central Asia and help upgrade the local railways there. Russia has an edge because those railroads were built by Russians and long run by Russian trained personnel. Russia sees itself as defending a trade monopoly it long enjoyed. Yet the Central Asian states are no longer part of Russia and more than willing to entertain competing bids.
Something Russia does not like to discuss openly is the fact that Chinese railroads extending into Central Asia would make it easier for China to carry out major military operations in the area. With rail lines extending deep into Central Asia China could more easily threaten a long feared invasion of Russia to take back the eastern territories that many Chinese believe are theirs. Such an invasion is unlikely as long as Russian nuclear weapons can hit China (via missile or bomber). But if that threat were diminished, a rail network in Central Asia that is connected to China would be a much more fearsome prospect for Russia. In the meantime, such a railroad is going to hurt the Russian economy because Chinese firms will have cheaper access to Central Asia and will likely drive out more expensive Russian products.