Everbody wants goods opportunity so they relocate to diff city... Many bihari are also there in kolkata so if they get this faster connectivty to kolkata why don't they will prefer this train... For people of katihar/araria/purnea/bhagalpur and some part of nepal also... If they want to go kolkata by flight he will have to go bagdogra airport and from there to bagdogra to kolkata he must loose there 10hr .... So in that comaprsion he will definetly prefer vande bharat because it will tak only 6hr to sealdah