People are waiting in line for a train.
People wait in line for underground for a train.
It does not indicate people are waiting in line for underground for the train.
exists e1 x1 x2 x3.(for(e1,x3) & n_train(x3) & in(e1,x2) & n_line(x2) & Actor(e1,x1) & v_wait(e1) & n_people(x1))
exists e1 x1 x2 x3 x4.(for(e1,x4) & n_train(x4) & in(e1,x3) & n_line(x3) & for(e1,x2) & n_underground(x2) & Actor(e1,x1) & v_wait(e1) & n_people(x1))