This chapter presents some of the results of a study project concerning the (pre-) feasibility of the development of the railway corridor no. IX in its section between the Greek port of Alexandroupolis in the north, and Moscow. The route of this corridor is: Alexandroupolis - Bucharest - Chisinaou - Kiev - Moscow, including a branch to Odessa. The aim of the work was to analyse the rail transport characteristics for passengers and goods along this 'southeast' section of corridor no. IX. The overall picture for passenger transport flows today is that there are very few truly international passenger flows, and these are low and decreasing in most sections of the corridor. The development of corridor no. IX into a credible transportation route for international freight and, to some extent, passenger transport is thus primarily an exercise in international cooperation and the ability of the 'partner' rail networks to adjust to the challenging requirements of modern railway transport.