Lost you. You are covering over a museum railway floor? Or subfloor and you need a new finish floor to simulate an old railway station floor? This is a display exhibit so there will be no/minimal traffic on the floor itself? Exhibit is subject to indoor or outdoor climate?
As long as the wood is dry and not treated, pine, fir or cedar would all work and can be stained or otherwise finished immediately. Pine or fir would be cheaper than cedar.
As long as the wood is dry and not treated, pine, fir or cedar would all work and can be stained or otherwise finished immediately. Pine or fir would be cheaper than cedar.