Nick finally found out what undercity work was.
So, it was putting grips onto the underside of the city.
The more Nick thought about it, the more sense it actually made.
They would need to expand the city again at some point, and they couldn't just attach a single layer of steel. That would be far too unstable.
The floor of the outer city was made of three layers, and all three layers added together were about a meter thick.
The upper layer was made of the big metal plates that the people walked on.
The middle layer was made of big and robust steel beams.
The lower layer was made of the same metal plates as the upper layer.
Originally, the entire floor of the Outer City was made of these layers, but the floor of the Dregs deteriorated over the years.
Parts of the Dregs had only had a single layer of metal plates and grates.