A crowd of people are standing on a train platform are unconcerned as a train passes them by.
A group of people are waiting for their train.
Standing on a train platform as a train passes by does not imply waiting for their train necessarily.
exists e1 p1 s1 x1 x2 x3 x4 x5.(on(e1,x3) & exists e2 s2 x6.(a_by(s2) & Manner(e2,s2) & Theme(e2,x1) & Actor(e2,x6) & v_pass(e2) & n_train(x6)) & n_thing(x1) & as(s1,p1) & Theme(s1,x5) & a_unconcerned(s1) & (x3 = x5) & n_platform(x3) & of(x3,x4) & n_train(x4) & Actor(e1,x1) & v_stand(e1) & of(x1,x2) & n_people(x2) & n_crowd(x1))
exists e1 x1 x2 x3.(for(e1,x3) & n_train(x3) & of(x3,x1) & n_thing(x1) & Actor(e1,x1) & v_wait(e1) & of(x1,x2) & n_people(x2) & n_group(x1))