I am not attempting to discourage anything just something I did and it has caused issues for me. In your second picture the track looks to be close to the edge. Especially coming off a curve there is a potential for a devastating drop. Also it is hard to tell from the pictures but make sure you tunnel entrance and exit are tall enough. I had a bridge that I made the height based on my F3 and a steamer that I had at the time. Unfortunately several boxcars and other rolling stock hit. If I had it to again I would make all the underpasses around 4 inches.