Here's a recentish article from SCMP. Sounds like they've got the route planning mostly done and are pushing ahead with the technical issues. Article says that Hyperloop tech is still in the early stages and many technical challenges lay ahead. We probably won't hear much more about it until the major tech breakthroughs are already made and tested because the Chinese state sector doesn't blow its trumpet until the project is almost done.

Seems like high level people from state and SOE organizations are involved so at least it's unlikely to be a startup grift.