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.
Mods introducing new content into the game.
Trains are great, but what if they could do even more?
I mean, use in recipes already crafted rails? Including modifier rails, like in this mod: https://mods.factorio.com/mods/Hermios/RailPowerSystem