 Complete the following phrase:  After the Russian Revolution, several lines of the MoscowKazan and SyzranVyazma routes were added to the SyzranZlatoust Railway. The network was renamed after Valerian Kuybyshev in 1936 as was the city of Samara. In 1989, the railway was the site of the worst train disaster in the history of the Soviet Union resulting in 575 deaths see 