Elon Musk’s tunnel-boring project has received more vague government approval for its equally vague plans to build an underground hyperloop between New York and Washington, DC. Last week, Washington, DC’s Department of Transportation issued a preliminary permit to Musk’s Boring Company to start digging at an abandoned lot in the northeast section of the city, according to The Washington Post.

Exactly how much digging — how deep and how long — is still unclear. A spokesperson for the Boring Company did not immediately respond to a request for comment, although they did tell the Post that the lot on New York Avenue could be a stop along a theoretical East Coast hyperloop.

“upbeat but noncommittal”

In comments to the Post, city officials were “upbeat but noncommittal” about the project. “We’re just beginning, in the mayor’s office, our conversation to get an understanding of what the general vision is for Hyperloop,” a spokesperson for DC mayor Muriel Bowser said, adding, “We’re open to the concept of moving people around the region more efficiently.”

Last summer, Musk tweeted that he’d received “verbal [government] approval” to build a hyperloop connecting New York City, Philadelphia, Baltimore, and Washington, DC. Later it was revealed that Musk had pitched the idea to White House adviser (and presidential son-in-law) Jared Kushner, who offered a tacit endorsement. The Boring Company has also received support from Maryland governor Larry Hogan, whose administration rolled out a welcome mat and provided a utility permit. Ground has yet to be broken on any of these projects.

Out west, the Boring Company has broken ground, and it’s currently digging a two-mile “test tunnel” underneath SpaceX’s headquarters in Hawthorne, California. The company is also seeking approval for a proposal to dig a 6.5-mile “proof-of-concept” tunnel underneath Los Angeles. This new, longer stretch would be used to perform verification tests of all the necessary systems, like electric “skates” to whisk riders in their cars to their destination, but also the equipment and processes being used to build the tunnels in the first place.

Of course, transportation experts question whether tunnels are really an answer to the quandary of overcapacity, in addition to questioning Musk’s claims that he can dig tunnels faster and at a fraction of the cost of traditional boring technology. The Boring Company has yet to publicly prove its claims.