People near railroad tracks in the woods.
People are by an airplane/
There is either a railroad or an airplane.
exists x1 x2 x3 x4.(n_wood(x4) & a_topic(x1) & near(x1,x2) & in(x2,x4) & n_track(x2) & of(x2,x3) & n_railroad(x3) & n_people(x1))
exists p1 x1.(exists x2.(by(x1,x2) & n_airplane/(x2)) & n_people(x1))