Workers fix train tracks.
People repair tracks.
Workers that fix train tracks are people who repair tracks.
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_fix(e1) & n_track(x2) & of(x2,x3) & n_train(x3) & n_worker(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_repair(e1) & n_track(x2) & n_people(x1))