If I were going to attempt this, I would invest in TransDEM, and georeference the TransDEM data with google Earth. Without looking, I know that the yard would lend itself to building it in parts; I would look for obvious "seams" to use to divide it. I've absolutely no doubt that, even if T:ANE won't run a route containing the yard, that at some point down the road, a version of Trainz will be able to run it, and if you start building it now, you just might have it done about the time a version of Trainz can run it.
But also, maybe you could be a successor collaborator to the work Mikeaust started.
ns