Right now, govt. is focusing on ndls-bct and ndls-hwh routes only bcoz by any means it wants to reduce the travel time of both these routes to an overnight journey so that it could regain it's consumers lost to Airways. upgrading tracks in ndls-mas roue to handle 200km/hr train will not reduce the travel time to an overnight journey so right now it's not in the priority list. This is the ultimate reason.