Many people looking at an old locomotive.
There is a group of people
Many people in one location, as they'd have to be to look at a locomotive, would be called a group.
exists e1 s1 x1 x2.(at(e1,x2) & n_locomotive(x2) & a_old(s1) & Theme(s1,x2) & Actor(e1,x1) & v_look(e1) & n_people(x1) & n_quantity(x1))
exists p1 x1 x2 x3.((x1 = x2) & of(x2,x3) & n_people(x3) & n_group(x2))