However it feels inconsistent to me that a foundation platform can hold a train and another else. Trains are heavy and involve lots of forces, so why couldn't it hold something else too?
No worries if you don't want to, just making a request.
I don't know, maybe there's something very specific and unintuitive about Fulgora that makes it easier to specifically build railway on top of oil, and needing to mix together all sorts of materials using cryotechnology to support everything else. Realism was never very big in Factorio anyway...