The people are walking by the train tracks.
A train speeds past people walking near the tracks.
Walking by train tracks does not imply the train speeds past.
exists e1 x1 x2 x3.(n_track(x2) & of(x2,x3) & n_train(x3) & n_people(x1) & by(e1,x2) & Actor(e1,x1) & v_walk(e1))
exists e1 e2 s1 x1 x2 x3 x4.(n_track(x4) & Theme(e2,x2) & Actor(e2,x1) & v_speed(e2) & near(e1,x4) & Actor(e1,x3) & v_walk(e1) & (x2 = x3) & n_people(x2) & a_past(s1) & Theme(s1,x2) & n_train(x1))