Metrorex approves pre-feasibility study for Bucharest Metro Line 4 extension, Romania June 30, 2018 | Europe News The Technical-Economic Council of Metrorex has approved the pre-feasibility study for Bucharest Metro Line 4 (M4) extension. Feasibility study is expected to be completed by 2019. Both the studies hav... This content is available to only subscribers. Username or E-mail Password Remember Me Forgot Password