People watch as two trains run on tracks.
People watch as two trains careen off some tracks.
If trains run on tracks they do not careen off them.
exists e1 p1 x1 x2.(exists e2 x3 x4.(on(e2,x4) & n_track(x4) & Actor(e2,x3) & v_run(e2) & n_train(x3) & card_eq_2(x3)) & as(e1,p1) & Theme(e1,x2) & Actor(e1,x1) & v_watch(e1) & n_thing(x2) & n_people(x1))
exists e1 p1 x1 x2.(exists e2 s1 x3 x4.(a_off(s1) & Manner(e2,s1) & Theme(e2,x4) & Actor(e2,x3) & v_careen(e2) & n_track(x4) & n_train(x3) & card_eq_2(x3)) & as(e1,p1) & Theme(e1,x2) & Actor(e1,x1) & v_watch(e1) & n_thing(x2) & n_people(x1))