the prussian eastern railway () was the railway in the kingdom of prussia and later germany until 1918. its main route, approximately long, connected the capital, berlin, with the cities of danzig (now gdańsk, poland) and königsberg (now kaliningrad, russia). at eydtkuhnen (now chernyshevskoye, russia) it reached the german empire's border with the russian empire. the first part of the line opened in 1851, reaching eydtkuhnen in 1860. by march 1880 the total route length reached , with a main parallel route in the south via bromberg (now bydgoszcz, poland) and thorn (now toruń, poland) to insterburg (now chernyakhovsk, russia). the lines were the first part of the later prussian state railways ().