Not quite ready to give up on using MDF just yet, I cut two 2' x 4' sheets of 3/4" MDF and glued them together. After painting that slab, I installed the legs hardware on the bottom.
While I liked the hand-laying method I used before, it is very time-consuming. So, since these were experiments, I decided to just buy five pieces of flextrack. I glued them to the slab to form the track under the coal tipple.
I built a skeleton mock-up of the coal tipple based on the design diagram I have of the Hazel Mine in Canonsburg, PA. This was to verify the position of the tracks and to make sure that it cleared engines on the tracks. I did paint the top of the slab, but in the end this proved to be too top-heavy and heavy in general. So, this idea was scrapped as well.