The team and their teams; all together not less than 250 experts working for leading companies in the field couldn't give one clear answer.
One quick look at #Ramsis Railway Station on any building that has the logo of the Egyptian Railway Company would give the short sharp answer.
2- Long living.
3-Easy to maintain.
This doesn't only define a criterea for selecting materials, but also defines the pool to pick from.
Anyway, I still agree that one or more of the #QRail (Interior Design Experts) may still prioritize the aesthetics in a railway station and say the he doesn't like the Look And Feel of the station. Although that this would sound neive to the majority of the field professionals, but simply sir a beautiful design shapes the right materials into a beautiful architecural space. If you think you can disagree with this primitive rule, Apple for an architectural school then.
For the amazing geometry with the right materials, see the Google images of Sweden Metro stations as an example.