Factorio Forums

Suggestion is to add ladder and second (and more) floors to the game.
So, the game will run as it is in x*y directions, and it will be added - z direction - to up.

So we can do "buildings" with ladders to the upper or down floor.
What about mechanic: its difficult to add vertical pipes now, so let it be to pass all throw the ledders: let belts or pipes can be places on the ledder.
All of them, who came from ladder - can be visible in the second floor, when we switch screen to it.

So, now to do it needs:
1. switcher between floors. Currently all out of the floor let be "water", and just ledders to the ground floor.
2. ladders

some changes in mechanic to make "ladders" to work like resource-portals between different maps (each floor is like different map).

So the bases will be more compact, also, it'll be like more spaceship plane with multiple floors on it. I saw, the devs already done some test with this.

Surfaces [0.13]
https://mods.factorio.com/mods/Simcra/Surfaces

Surfaces_remake [0.15]
https://mods.factorio.com/mods/Erdbeerb ... ces_remake

Currently there are no actual plans on adding Z axis to the game. Maybe (hopefully) devs will consider adding something like bridges or tunnels for trains but thats it.
There might also be something like "pseudo 3D" (like old C&C where cliffs are just impassable tiles with cliff graphics).

Not at least in Factorio 1.0
Maybe in future but not now.

Actually the whole point of Factorio is making you solve puzzles such as how to fit particular task in a limited space with existing tools. So there is no point in removing it.
For now there are mods that can let you make things more compact.
The most advanced of them all is Factorissimo. This one allows you building mini-factories which are placed like common buildings but you can actually enter them and they are "bigger from the inside".