▁from ▁all ▁directions ▁( from ▁Berlin , ▁Fl ens burg , ▁Lü beck / W ism ar / R ost ock / Str als und / S ass nitz , ▁Han over ▁and ▁Bre men ). ▁With ▁the ▁division , ▁the ▁Berlin – H amb urg ▁line ▁lost ▁its ▁importance , ▁and ▁the ▁traffic ▁to ▁and ▁from ▁Hamburg ▁was ▁now ▁concentr ated ▁mainly ▁in ▁the ▁north - s outh ▁direction . ▁While ▁the ▁Hamburg – H an over ▁line ▁was ▁elect r ified ▁in ▁ 1 9 6 5 ▁and ▁the ▁Hamburg – Bre men ▁line ▁was ▁elect r ified ▁in ▁ 1 9 6 8 ▁and ▁both ▁lines ▁were ▁later ▁upgrad ed ▁for ▁spe eds ▁up ▁to ▁ 2 0 0   km / h , ▁there ▁were ▁no ▁similar ▁projects ▁on ▁the ▁Berlin – H amb urg ▁line . ▁▁ ▁In ▁ 1 9 7 6 ▁the ▁line ▁was ▁re - open ed ▁from ▁Nau en ▁to ▁the ▁newly ▁re - est ab lished ▁border ▁crossing ▁at ▁Sta aken , ▁providing ▁a ▁more ▁direct ▁line ▁to ▁Hamburg . ▁In ▁the ▁ 1 9 7 0 s ▁the ▁line ▁between ▁Nau en ▁and ▁Ludwig sl ust ▁( and ▁continu ing ▁to ▁Sch wer in ▁on ▁the ▁Ludwig sl ust – W ism ar ▁line ) ▁was ▁re built ▁as ▁two ▁tracks . ▁ ▁Sub urban ▁traffic ▁ ▁Berlin ▁The ▁sub urban ▁line ▁of ▁the ▁Berlin - H amb urg ▁railway , ▁serving ▁Nau en , ▁had ▁been ▁part ▁of ▁the ▁Berlin ▁sub