▁Stuttgart ▁ 2 1 ▁is ▁a ▁railway ▁and ▁urban ▁development ▁project ▁in ▁Stuttgart , ▁Germany . ▁ ▁It ▁is ▁a ▁part ▁of ▁the ▁Stuttgart – A ugs burg ▁new ▁and ▁upgrad ed ▁railway ▁and ▁the ▁Main ▁Line ▁for ▁Europe ▁( Par is — V ien na ) ▁within ▁the ▁framework ▁of ▁the ▁Trans - Europe an ▁Network s . ▁ ▁Its ▁core ▁is ▁a ▁renew ed ▁Stuttgart ▁Haupt bahn hof , ▁among ▁some ▁ ▁of ▁new ▁rail ways , ▁including ▁some ▁ ▁of ▁t unn els ▁and ▁ ▁of ▁high - speed ▁lines . ▁ ▁The ▁project ▁was ▁officially ▁announced ▁in ▁April ▁ 1 9 9 4 . ▁ ▁Const ruction ▁work ▁began ▁on ▁ 2 ▁February ▁ 2 0 1 0 . ▁In ▁March ▁ 2 0 1 3 , ▁total ▁costs ▁were ▁officially ▁estimated ▁at ▁ 6 . 5 ▁billion ▁eu ros , ▁the ▁previous ▁estimate ▁being ▁ 4 . 5 ▁billion ▁eu ros ▁in ▁ 2 0 0 9 . ▁He ated ▁debate ▁en su ed ▁on ▁a ▁broad ▁range ▁of ▁issues , ▁including ▁the ▁relative ▁costs ▁and ▁benefits , ▁ge ological ▁and ▁environmental ▁concerns , ▁as ▁well ▁as ▁performance ▁issues . ▁ ▁As ▁of ▁ 2 0 1 9 , ▁the ▁start ▁of ▁operation ▁is ▁expected ▁in ▁late ▁ 2 0 2 5 , ▁versus ▁an ▁initial ▁estimation ▁of ▁ 2 0 1 9 ▁( made ▁in ▁ 2 0 1 0 ). ▁ ▁Con cept ▁ ▁The ▁concept ▁attempts ▁to ▁combine ▁plans ▁for ▁high - speed ▁links ▁from