Complex sentence: The part of the railway south of Raasuli (Orekhovo) was on the Russian side of the Finnish-Russian border and was operated by at first by Nikolai Railway and later, after name change, the October Railway.
Split into simpler sentences: The part of the railway south of Raasuli (Orekhovo) was on the Russian side of the Finnish-Russian border. This section was operated by at first by Nikolai Railway and later, after name change, the October Railway.