Workers in hard hats at a railroad tracks construction site.
Some people are performing construction.
Workers in hard hats at construction site implies that they are performing construction at the site.
exists e1 s1 x1 x2 x3 x4 x5.(Theme(e1,x4) & Actor(e1,x1) & v_track(e1) & n_site(x4) & of(x4,x5) & n_construction(x5) & in(x1,x2) & at(x2,x3) & n_railroad(x3) & n_hat(x2) & a_hard(s1) & Theme(s1,x2) & n_worker(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_construction(x2) & n_people(x1))