People waiting to get on a train or just getting off.
There are people waiting on a train.
waiting to get on a train or just getting off is a rephrase of waiting on a train.
(exists e1 p1 x1.(Topic(e1,p1) & Actor(e1,x1) & v_wait(e1) & exists e2 x2.(on(e2,x2) & n_train(x2) & Actor(e2,x1) & v_get(e2)) & n_people(x1)) | exists e3 s1 s2 x3.(a_just(s2) & Manner(e3,s2) & a_off(s1) & Manner(e3,s1) & Actor(e3,x3) & v_get(e3) & n_people(x3)))
exists p1 x1 e1 x2 x3 x4.((x1 = x2) & on(e1,x4) & n_train(x4) & Actor(e1,x3) & v_wait(e1) & (x2 = x3) & n_people(x2))