Someone on this forum, or maybe it was another forum, used post offices to flatten a hill ! That's wild. If I remember right he started at the base of the hill, right next to the track, and moved upslope deleting each post office after building it. Many, many, many, many post offices later he had flattened the hill.
And...then he posted screen shots of flying trains! Apparently he stopped a train on a hill, flattened the hill with P.O.s and the train was left suspended in mid-air. He posted pics of 2 or 3 trains 'flying'.
Now, is this cheating? Not sure, but it tells me this guy had a lot of time on his hands which he didn't know what to do with.