The people are walking by the train tracks.
There are people walking.
People are walking other are walking by the train tracks.
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 p1 x1 e1 x2 x3.((x1 = x2) & Actor(e1,x3) & v_walk(e1) & (x2 = x3) & n_people(x2))