With the shed finished I built a concrete base to surround the track inside the shed. I started out with a sub-base of 3/16 MDF to bring it up to the height of the cork roadbed then I glued on offsets to bring the base even with the track ties.
Once satisfied with the fit I took the individual pieces and painted them 'concrete'. I used an awl to make the expansion lines and the cracks. Once the concrete color dried I went over the expansion lines and cracks with an India Ink/water wash.
I had two platforms I bought from Crescent Motor works a while back. I added a brown wash to them then glued on details from a box of 'nick knacks'. there is some Preiser and some Woodland Scenics in there. The platforms are not glued to the base. I will wait till I can back in an locomotive to ensure nothing hits.
The shed will not be glued to the base for maintenance reasons. I still need to add some tanks (as the guru Alan Graz says 'a building ain't a building without a tank or two'.