Trans-Siberian Railway men and ammunition coming from west to east would have to wait in the sidings, whilst troops and injured personnel in a troop train travelling from east to west went along the line. Thus the Japanese were quickly able to advance whilst the Russians were awaiting necessary troops and supplies. After the Russian Revolution of 1917, the railway served as the vital line of communication for the Czechoslovak Legion and the allied armies that landed troops at Vladivostok during the Siberian Intervention of the Russian Civil War. These forces supported the White Russian government of Admiral Alexander Kolchak, based in
Trans-Mongolian Railway line began in 1947, reaching Ulan Bator from the north in 1950 and the Chinese border in 1955. Before that the only railways in Mongolia had been a line (opened in 1938) connecting the coal mines at Nalaikh to the capital and a Soviet-built freight-only branch (completed in 1939) from Borzya on the Trans-Siberian Railway to Bayantümen, Dornod near Choibalsan in north-eastern Mongolia. Russian Irkutsk State University of Railway Engineering opened its Ulaanbaatar branch in June 2009. The Mongolian Railway company "Mongolyn Tömör Zam" carries 80% of all freight and 30% of all passenger transport within Mongolia. In the aftermath