Not "new" tech
Ms. Osborne wrote:
"One day soon, it may not be an impossibility that trains traveling through vacuum tunnels...."
Sorry to tell you but the "Great Bird of the Galaxy" Gene Roddenberry used that tech in one of his "post-Star Trek" movies. He wrote a story that was made into a movie in 1973 called "Genesis II" where they had "sub-shuttles" that ran in straight lines through the Earth's crust. The only apparent difference was that, if these tunnels were vacuums, it didn't show that. They had "open air" platforms, similar to a subway platform.
As for this scramjet being allowed to disintegrate, considering that it had to be carried aloft to 50,000 feet under a B-52, it probably had no landing gear to save weight. Less weight means faster acceleration, higher altitude, and greater speed. At the lower speeds after the test, this craft may not have sufficient control surfaces to safely land the craft. The only bad thing about that is being unable to recover any of the surface materials to examine them for the effects of the high speed air on them.
