Due to territorial changes, the line now lies within five countries and crosses the eastern border of the European Union three times.

Passenger trains between Saint Petersburg and Warsaw used to travel through Brest instead and a new line called Rail Baltica is under development to improve the direct connection between Poland and Lithuania.

In February 1851 the Tsarist Government of Russia made a decision to build the St. Petersburg–Warsaw railway line with a length of approximately 1,250 kilometers.

The first section of the railway was completed in 1853 between Saint Petersburg and Gatchina, with daily scheduled train service started on 31 October 1853.

Since 2014 the line is being modernized to ultimately allow passenger trains to run at 200 km/h (125 mph) and freight trains at 120 km/h (75 mph), works include renewal of tracks and overhead lines, replacing level crossings with tunnels or overpasses and installation of ETCS level 2.

The original route continues south-west as PKP rail line 21 terminating at the Warszawa Wileńska station in Warsaw Praga district, without reaching the city center.

Instead a project called Rail Baltica is underway to upgrade existing infrastructure and build new standard gauge lines in order to improve the rail connection from Poland to Lithuania, Latvia, further to Estonia and eventually to Finland, running entirely within EU territory.