Construction workers building a railroad.
Workers are building train tracks.
Construction workers are workers, and building train tracks implies building a railroad.
exists e1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_build(e1) & n_railroad(x3) & n_worker(x1) & of(x1,x2) & n_construction(x2))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_build(e1) & n_track(x2) & of(x2,x3) & n_train(x3) & n_worker(x1))