Elon Musk tweeted last week that he has gotten preliminary approval for a Hyperloop tunnel on the East Coast, running from NY to DC, via Philadelphia and Baltimore. Just received verbal govt approval for The Boring Company to build an underground NY-Phil-Balt-DC Hyperloop. NY-DC in 29 mins. — Elon Musk (@elonmusk) July 20, 2017 29 minutes …