There are several people standing on the platform waiting for the subway or train.
a group of people walking down the street
People walking down the street contradicts with people standing on the platform.
exists p1 x1 x4 x5.((n_subway(x5) | n_train(x5)) & n_platform(x4) & exists e1 e2 s1 x2 x3.((x1 = x2) & for(e1,e2) & for(e2,x5) & Actor(e2,x3) & v_wait(e2) & on(e1,x4) & Actor(e1,x3) & v_stand(e1) & (x2 = x3) & n_people(x2) & a_several(s1) & Theme(s1,x2)))
exists e1 x1 x2 x3 x4.(n_street(x4) & a_topic(x1) & of(x1,x2) & down(e1,x4) & Actor(e1,x3) & v_walk(e1) & (x2 = x3) & n_people(x2) & n_group(x1))