the line was extended from königsberg on 6 june 1860 to insterburg (polish: wystruć, russian: черняхо́вск) via gumbinnen (polish: gąbin, russian: гу́сев), trakehnen (polish: jasna polana, russian: я́сная поля́на) and stalluponen (nesterov, russian: не́стеров) and extended to eydtkuhnen (chernyshevskoye, russian: черныше́вское) on the russian frontier on 15 august 1860, a total distance of 153 km. transhipments and transfers took place at the station over the border then called virbalis in lithuanian (german: wirballen, russian: verzhbolovo, вержболово, polish: wierzbałowo), now called kybartai. later the gauge-conversion of carriages on through trains to the broad gauge tracks of the russian railways was carried out there. in 1871, the 34 km shorter schneidemühl–konitz–dirschau (now tczew) line was built parallel, bypassing bromberg. after the completion of these sections work began with duplicating the line from küstrin east. the route from berlin to kustrin however, was already duplicated. in addition, there were several sections of line built parallel with the main line over short sections.