Work in Progress -
I tried to model the entire area of Manhattan below Central Park in 3D but turns out the lines are too thin and the changes in elevations look to subtle when you zoom out in a bird's-eye view. So I had to exaggerate the width of the tracks. But after rebuilding the 2D lines in Rhino the lines look so wiggly, so it looks a little weird now. I will try to make a cleaner and neater version!