The paper considers main works on the history of Trans-Siberian Railway construction written by the Russian and Western authors. Main attention is paid to historiographical discussions on the main reasons for the railroad construction. In the Pre-revolutionary most of such debates were initiated by the Siberian regionalists who opposed the railroad's proponents. Soviet historians at first neglected modernization effects of the railway construction, but after the Great Patriotic War and the construction of BAM in 1970s they paid more attention to the history of Trans-Siberian Railway. Western studies were usually based on the “modernization approach”. Some researchers analyzed mostly economic reasons for the railroad's construction, while others demonstrated the role of strategic, military and political factors. Such controversies were greatly determined by the multi-functional nature of the Trans-Siberian Railway serving at the same time strategic, military and economic interests of Russia. At the same time such debates proved that the more objective and unbiased analysis of Siberia’s social and economic development in the pre-revolutionary period is needed.