while FARL can place Straight Waterways, it can't properly read the re-skinned Chain/Signal Buoys as Rail Signals, so it throws the following error with the shown-in-hand blueprint (Signal on left, Rail Signal on right, Floating Power Pole on right)
https://i.imgur.com/ClsquF9.png

I gave it a quick try and fixed the error, but CargoShips seems to mess with signal positions, resulting in more FARL errors down the line.
I'll give it more of a try over the weekend.

it might have to do with Waterways being 4-wide instead of the vanilla rail 2-wide

I gave it a go a week ago, and i'm afraid it will have to wait for the rewrite of FARL i have planned for July.