The Frankfurt ( Oder ) – Poznań line , which branches off the Lower Silesian-Mark line at Frankfurt ( Oder ) is part of an east-west link via Warsaw to Moscow . As Soviet troops advanced this line was rebuilt with ( ) for the supply of the Red Army , so that on 25 April 1945 the first Soviet military train could reach the Berlin city limits . On 28 June 1945 , the first passenger train ran from Moscow to the Silesian station . In order for Joseph Stalin to travel to the Potsdam Conference a track to Potsdam was also changed to Russian broad gauge . The broad gauge tracks were returned to standard gauge by 20 September 1945 in order to increase rail capacity
Potsdam Conference
Potsdam Conference
Berlin–Wrocław railway