many people wait for the train.
Some people are waiting for the orange train.
Just because people are waiting for the train does not mean the train is orange. It could be any color.
exists e1 x1 x2.(n_train(x2) & for(e1,x2) & Actor(e1,x1) & v_wait(e1) & n_people(x1) & n_quantity(x1))
exists e1 x1 x2 x3.(n_train(x2) & of(x2,x3) & n_orange(x3) & for(e1,x2) & Actor(e1,x1) & v_wait(e1) & n_people(x1))