A fine way of making a larger Railroad setup, is using modules.
On our Modelrailway Club in Venlo (NL), called MGV, we are no exception.
These modules are moveable, also to shows, and easy to acces for every detail while construction is going on.
For coupling of railpower and a low current (it is all leds !) 12 or 16V we use a simple connector board.
Each side of these modules has this board installed, and short 5 wire cables are used for interconnection.
On the module itself, these boards are interconnected.
Installation of a large setup is now pretty simple.
Just running LocoNet cables from one module to the next,(we are using GCA LocoNet network for many years already on three large layouts)
and the 5 wire cable from above and all connections are settled.
This board is a D.I.Y. project, no boards available.
Board is single sided and on Eurocard PCB contains 10 items.
You can make your own standard of how and which connections are made and used.