The sign indicates a marker for The Arlington Line.
The sign is at a train station.
Signs are not only situated at a train station.
exists e1 x1 x2 x3 x4.(ne_org_line(x3) & (x3 = x4) & ne_org_arlington(x4) & n_sign(x1) & Theme(e1,x2) & Actor(e1,x1) & v_indicate(e1) & for(x2,x3) & n_marker(x2))
exists p1 x1.(n_sign(x1) & exists x2 x3.(at(x1,x2) & n_station(x2) & of(x2,x3) & n_train(x3)))