I believe anyone in a train like this, during an accident, wouldn't feel a thing and would be considerably more than dead long before all the parts would stop moving from such a wreck.
99% would die of heart attacks long before they became mush I guess.
I don't think we can do fast trains until we kill off terrorists but we might have better luck in Canada. Hudson's Bay is becoming a warm weather ice free port for much of the year and improved rails are planned to ship Midwest grain to Europe via RR to Hudson's Bay and then by ship.
That's remote country and Canada has far fewer enemies. The other idea is an old one but would connect almost the entire world. Canada could probably help with some of the costs. Their prairies would use the same markets. Then there's Russia, South Korea and China and perhaps Japan.