Elon Musk sent yet another cryptic tweet Friday about his plan to connect Washington DC and New York City via Hyperloop.
The Tesla and SpaceX CEO clarified that he had received “verbal approval… at the federal level,” to dig a massive tunnel for the high-speed transit system, which would also stop in Philadelphia and Baltimore. The entire trip, he said, would take just 29 minutes.
But it’s still unclear what “verbal approval” means. On Thursday, the Department of Transportation referred Business Insider to a White House spokesperson who said there have been “promising conversations” about the project.
“We have had promising conversations to date, are committed to transformative infrastructure projects, and believe our greatest solutions have often come from the ingenuity and drive of the private sector,” a White House spokesperson wrote in a statement.
But Musk still has a ways to go before receiving city and state approval.
“Still a lot of work before formal, written approval, but this opens door for state & city discussions,” Musk tweeted Friday morning.
New York and Philadelphia city representatives told Business Insider that they have not been in talks with Musk or The Boring Company about the proposed project.
Musk visited the White House on three separate occasions this year when he sat on President Donald Trump’s economic advisory board and the Manufacturing Jobs Initiative. He left both advisory councils after the US withdrew from the Paris Climate Agreement in June.
A Hyperloop is a high-speed transportation system that Musk outlined in a “white paper” in 2013. It would work by shooting pods through a vacuumed-sealed tube at speeds up to 700 mph.
Hyperloop One, a startup independent from Musk’s Boring Company, completed the first successful test of a Hyperloop system earlier this month. The pod, however, only reached 70 mph and travelled for 5.3 seconds.
Musk’s Boring Company is focused on digging tunnels to support various forms of transportation.
Musk has said the tunnel would be used to transport people and cars via an electric skate.
The Boring Company is in “preliminary” talks with Chicago Mayor Rahm Emanuel about digging a tunnel that would connect downtown Chicago with O’Hare International Airport.
Musk said in late June that he has had “promising conversations” with LA Mayor Eric Garcetti about building a tunnel between Los Angeles International Airport and Union Station, a main transit hub that connects Los Angeles to distant suburbs. Garcetti said he was considering using Musk’s tunnel to support a high-speed rail connection.
Although the LA tunnel would support a high-speed rail, Musk’s Thursday announcement marks the first time the company has teased digging a tunnel to support a Hyperloop.
Tunnel-boring is a notoriously expensive process, but the company is looking to cut down costs by building a machine that can dig and place reinforcements in the wall at the same time, Musk said during an April TED Talk. Tunnelling machines traditionally dig for half the time and then go back to add reinforcements, a longer and costlier process.
The Boring Company has already completed its first tunnel segment in Los Angeles on SpaceX’s property. For any of Musk’s plans to be fully realised, he will need to secure permits through city and state representatives.