Hyperloop
A wonderful proposal and inspiring: I think the air bearing, partially evacuated tube and axial flow compressor powered by onboard battery are an innovative combination worth exploring,  and I am sure with the correct leadership and political will could produce a really useful enhancement of transport infrastruture. However on reading many of the comments bemoaning current state of construction in the US, as well as unions and vested interests; had to provide this quote of Machiavelli's:
It ought to be remembered that there is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in the introduction of a new order of things. Because the innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may do well under the new. This coolness arises partly from fear of the opponents, who have the laws on their side, and partly from the incredulity of men, who do not readily believe in new things until they have had a long experience of them.