NoaB

Unless you have a central AC in your home, AC units usually look like in this photo. Each room would have one. Big rooms might have 2 or more. I did notice ACs do breakdown multiple types a year. But I'm not sure if it is because of sand or simply because of overuse. (You cant live without AC. houses and apartments are compartmentalized with doors so you can close off rooms and have their AC off) Siemens markets their Riyadh Metro Trains as having "Special filters and sealing systems also prevent sand from entering the vehicle components and passenger compartment." (and I assume Bombardier and Alstom are doing similar things. They also building trains for the project) Btw are we going off topic?😅

In Riyadh? It's sunny all year with almost no humidity. I think it rains there less than a few times a year. And it actually snows a tiny bit once every few years. I wouldn't know too much. I lived in Jeddah, where its sunny all year, rains about 5 times per year, and the humidity is always over 80%. Almost no weather. (Nobody looks at the forecast)

The Riyadh Metro currently unders construction is covering the concrete with some sort of panels that have the line color on it. The exposed concrete is also painted white. Some of the concrete viaducts pieces come curved. (first image)