Business magnate and inventor Elon Musk tweeted that he has received “verbal” government approval for his tunnel-building company to construct infrastructure for a hyperloop transportation system connecting Washington, D.C., Baltimore, Philadelphia and New York City.

Hyperloop is a mode of transportation championed by Musk that propels pods through low-pressure tubes. The low air resistance and reduced friction allows the pods to hit blazing speeds of more than 700 mph. Musk suggested the hyperloop…