Rooftop Enhancements (or basement) like solar panels or basement boilers

Rooftop and/or basement enhancements to buildings.
- Rooftop: Rain catch, solar panels, wind turbines, train terminals, exhaust stacks, greenhouses
- Basement: Boiler room for steam, water cistern, storage, subway terminal, gas injection pump
- Elevated or underground connection points for supplies (conveyors/tubes).
Could be starting point for true vertical stacking production (structures above/below other structures.