A vehicle, in particular a rail vehicle, for a bidirectional operation at a nominal travelling speed, in particular above 160 km/h to 200 km/h, in a respective direction of travel, comprising - at least one vehicle module (102; 202; 302; 402) with a wagon body (103; 203; 303; 403) being supported on a running gear configured to run on a track defining a track level; - said vehicle module (102; 202; 302; 402) defining a longitudinal direction, a transverse direction and a height direction; - said wagon body (103; 203; 303; 403) having an outer skin (103.4; 203.4; 303.4; 403.4) defining a generally prismatic body section and a non-prismatic laterally tapering head section (103.2; 203.2; 303.2; 403.2) located at one of its ends; - said vehicle module (102; 202; 302; 402), at a transition between said body section, and said head section, having a maximum vehicle height dimension above said track level in said height direction; - said wagon body (103; 203; 303; 403), in an upward facing part of said head section, having a flow separation section (103.6; 203.6; 303.6; 403.6) comprising a flow separation device (103.7; 203.7; 303.7; 403.7), in particular a flow separation edge (103.9; 203.9; 303.9; 403.9); - said flow separation device (103.7; 203.7; 303.7; 403.7), in particular, said flow separation edge, in a transversally central area of said wagon body (103; 203; 303; 403) and at least in an activated state, being located at a flow separation height in said vehicle height direction; - said flow separation device (103.7; 203.7; 303.7; 403.7) providing a persistent separation of an upper fraction of an airflow from said outer skin (103.4; 203.4; 303.4; 403.4) of said wagon body (103; 203; 303; 403) when said vehicle module (102; 202; 302; 402) runs at said travelling speed with said head section (103.2; 203.2; 303.2; 403.2) forming a trailing end of said vehicle module (102; 202; 302; 402); characterized in that - said flow separation device (103.7; 203.7; 303.7; 403.7), at least in said activated state, defining a generally concave flow separation section of said outer skin, - said flow separation height ranging up to 50% to 65% of said maximum vehicle height dimension, preferably from 25% to 50% of said maximum vehicle height dimension, more preferably from 30% to 46% of said maximum vehicle height dimension, even more preferably from 33% to 39% of said maximum vehicle height dimension. - at least one vehicle module (102; 202; 302; 402) with a wagon body (103; 203; 303; 403) being supported on a running gear configured to run on a track defining a track level; - said vehicle module (102; 202; 302; 402) defining a longitudinal direction, a transverse direction and a height direction; - said wagon body (103; 203; 303; 403) having an outer skin (103.4; 203.4; 303.4; 403.4) defining a generally prismatic body section and a non-prismatic laterally tapering head section (103.2; 203.2; 303.2; 403.2) located at one of its ends; - said vehicle module (102; 202; 302; 402), at a transition between said body section, and said head section, having a maximum vehicle height dimension above said track level in said height direction; - said wagon body (103; 203; 303; 403), in an upward facing part of said head section, having a flow separation section (103.6; 203.6; 303.6; 403.6) comprising a flow separation device (103.7; 203.7; 303.7; 403.7), in particular a flow separation edge (103.9; 203.9; 303.9; 403.9); - said flow separation device (103.7; 203.7; 303.7; 403.7), in particular, said flow separation edge, in a transversally central area of said wagon body (103; 203; 303; 403) and at least in an activated state, being located at a flow separation height in said vehicle height direction; - said flow separation device (103.7; 203.7; 303.7; 403.7) providing a persistent separation of an upper fraction of an airflow from said outer skin (103.4; 203.4; 303.4; 403.4) of said wagon body (103; 203; 303; 403) when said vehicle module (102; 202; 302; 402) runs at said travelling speed with said head section (103.2; 203.2; 303.2; 403.2) forming a trailing end of said vehicle module (102; 202; 302; 402); characterized in that - said flow separation device (103.7; 203.7; 303.7; 403.7), at least in said activated state, defining a generally concave flow separation section of said outer skin, - said flow separation height ranging up to 50% to 65% of said maximum vehicle height dimension, preferably from 25% to 50% of said maximum vehicle height dimension, more preferably from 30% to 46% of said maximum vehicle height dimension, even more preferably from 33% to 39% of said maximum vehicle height dimension.