Still closed, probably until Summer/Fall of 2017. They do have several of the trains out in the stations (at least New Orleans Square that I know of) and you can go up and look at them and talk to the engineers.
They said down "about a year" and closed Jan '16. Unsubstantiated rumors have said April '17...most are guessing spring/summer as mentioned above but noting official.
It is possible for guests to go up and pull a whistle near the train parked at the New Orleans Square station -- that could be what was audible on a blog post. The whistle is part of an engine cut-away that guests can look at. It is also possible to sit in the very front of the train (which is normally much too hot for guests to be allowed near) and talk with a conductor about how the train works.
I wish they would allow guests to walk through the Grand Canyon and the dinosaurs part of the train route (though maybe they are working on that, too?). That is my favorite part of the train ride.