"American Heritage Railways Inc. has decided to
permanently cease operations and close Mt. Rainier Railroad for the foreseeable future." (emphasis added)
I would say that closing for good is a pretty accurate title for this thread. I assume the name Mt. Rainier Railroad belongs to American Heritage so any operation that arises from the ashes will have a new name. Remember, it was the Mt. Rainier Scenic Railroad before American Heritage took over.
One would hope that the Washington Forestry Museum would be able to resume operation at some point in the future, but the reason they turned the operation over to American Heritage was they were not succeeding financially. With American Heritage exiting, I'm not sure what path forward exists.
Michael Allen