Accidentally bumping into Newton yesterday, we had a whole train ride to discuss something that came to our mind. Here's a scratch from today:
img removed

I have no proof yet but Newton said Peter wanted to abandon refined materials and having everything built up from raw material. Yeah, okay. Maybe this is wrong, dunno ;)
So, this idea is the... automatic settlement system or somewhat.

The Trails
I think we almost agree that idea didn't hit the spot. So the rails have to be on the wall/tunnel/midair. I got this thought from Zelda. Precisely, from the spinner. There are basically two parts of what the rail is made of:
The rail part, some bars to cling to: img removed
The crossing, something round, gearwheel-like: img removed

To construct your railway, you build a crossing and however connect it with an existing crossing (thinking still in progress...) (maybe with a line?). The railway can point in any direction. A connection between two crossings is always straight. You create your network by constructing crossing. And of course with:

The Railway Station
Something round, looking like any thing where you can engage the 'gearwheel movement system'. The flag is to show what status the station is in (think of the signal): img removed
Here you can latch the lorries. The status thing, I think there are two options suitable: 1 - Drop load and return to your starting point, 2 - Stop & disengage

Movement
I favour the following: you push a lorry to the station, engage it and the select an ending station (click through, whatever, the viewport hopping to the stations or so).  The lorry starts moving automatically, searching its way throught the network. I think something else is possible with a lot of options at every crossing with levers and stuff.
Movement should be quick, so it's fun! And why it's fun? Because you can take the ride, too, of course! Clonks can drive inside the lorries - awesome!

Signs
I draw this on the scratch. This is kinda of a bonus to the whole railway system. You can build signs along the rail. We thought of the following:
- Drop load
- Drop objects of kind x (selectable)
- Wait until something's dropped into you
See the draft for an example. Another one goes with another bonus:
- shoot at angle x (see below)

Connection to buildings
It should be possible to connect your buildings to the rails. Thus automate your production. Here's an example:
You construct your sawmill, connect the rails, push in a lorry. Then you have the following options:
- automatic drop, whenever you drop a tree in it, it starts the lorry dropping the wood off whereever you wanted it to do this
- whenever another building demands wood, the sawmill will let it go

So this is what happens in your automatic settlement (I take the CR buildings as examples):
- you go to your anvil, want to produce a sword
- anvil try and finds metal, nothing there
- anvil informs the foundry, need metal
- ore is stored in the foundry, automatically driven there from your mine where you mined it
- foundry informs the sawmill, need wood
- wood is stored inside the sawmill, because you stuffed some trees in there, the sawmill starts a lorry with wood
- foundry produces metal, then starts a lorry, too (lorry was stored in there, the one from the sawmill returned earlier)
- finally you have some metal at your anvil, fully automatic!

Yeah, I think you got the clue

What else?!
I mentioned it above. What about a railway cannon. Automatic mining with the 'shoot at angle x' sign. Automatic attacks. Whatever!