Add some beautiful bridge-rails (wood, iron, stone-brick) that can be placed on water, and change default Big-electric-pole and rail-signals to be placeable on water.
I started to use Cave mod and i get the idea to use FARL with your beautiful bridges to feel something like a TBM (tunnel boring machine).
But build bridges underground...
ITS NOT FUCKING IMMERSIVE !!!
Can you be a very nice modder and make a tunnel like railway? it will look very cool and very Immersive!
Sorry my grammar, english isnt my native language.