Elon Musk first started the idea of a high-speed hyperloop transport system between cities way back in 2013, but he left it to other companies to develop the idea further. Fast forward to 2017, when Musk announced that would build a hyperloop system after all, starting with the New York to Washington D.C. route. Now, Musk has tweeted that The Boring Company will attempt to build a working hyperloop "in the coming years."
As a reminder, hyperloop is a system that runs pods with passengers or cargo through low-pressure tubes at speeds up to 800 MPH. It's an idea that could work in theory, but it's never been proven to run at anything close to those speeds in practice.
Musk noted that hyperloop would be the fastest way of getting from one city center to another for distances less than 2,000 miles, with Starship being faster for longer journeys. He also noted that "underground tunnels are immune to surface weather (subways are a good example), so it wouldn’t matter to hyperloop if a hurricane was raging on the surface. You wouldn’t even notice."
In the coming years, Boring Co will attempt to build a working Hyperloop.— Elon Musk (@elonmusk) April 24, 2022
From a known physics standpoint, this is the fastest possible way of getting from one city center to another for distances less than ~2000 miles. Starship is faster for longer journeys.
In fact, Paris subways are susceptible to flooding when the Seine river is high, for instance, and the New York subway system flooded during Hurricane Sandy, as TechCrunch noted. Still, perhaps hyperloop could be designed to be flood-resistant.
Meanwhile, Musk founded the Boring Company in late 2016 as a way to dig tunnels efficiently for cars and high-speed trains. That company recently received a big cash injection that valued it at around $5.7 billion, but it has yet to complete any significant projects, apart from the Las Vegas LVCC Loop with 1.7 miles of tunnels. (It has announced, but shelved or cancelled several other projects).
There's an obvious synergy between hyperloop and The Boring Company. It could become a lot more practical once the company finishes development of Prufrock-3, a machine that will supposedly be able to dig seven miles of tunnel per day. That's about fifty times faster than the company's current Prufrock-2 machines that can do just one mile of tunneling per week.