In 1909, a 22-year-old rocket pioneer named Robert Goddard — yes, that Goddard, the father of modern rocketry — sketched out a transportation system that could whisk passengers from Boston to New York in twelve minutes. His vehicle wouldn't fly. It would slide through an evacuated steel tube, magnetically levitated, hitting roughly 1,000 mph. Goddard never published the design; it was found among his papers after his death in 1945. Hyperloop, in other words, is more than a century old.

The idea is mechanically simple and physically brutal. At sea-level pressure, air resistance grows with the square of velocity — it's the dominant drag on any high-speed train and the reason the TGV plateaus around 200 mph in commercial service. Pump most of the air out of the tube, and that drag essentially disappears. What remains is a vehicle that, in theory, could exceed 4,000 mph using a tiny fraction of the energy a jet burns to do the same trip — because a jet must continually shove atmosphere out of its way.

The catch isn't physics. It's plumbing.

• A continental-scale tube must hold near-vacuum across thousands of kilometres while expanding and contracting with daily temperature swings.
• Any breach — a hairline crack, a careless backhoe, a small earthquake — sends a shockwave of in-rushing air down the tube at the speed of sound, hitting any vehicle inside like a wall.
• Emergency egress is, to put it gently, an unsolved problem. You cannot simply open a door at 0.001 atmospheres while traveling faster than a rifle bullet.

If the concept feels familiar, you've probably seen its tiny ancestor. The pneumatic tubes that shuttled cash canisters around department stores and hospitals well into the 1980s are a vactrain in miniature — Victorian-era infrastructure that briefly carried actual passengers in London's 1860s Crystal Palace pneumatic railway and beneath Broadway in Alfred Beach's secretly-built 1870 demonstration line. New York's mail moved this way for decades.

The modern revival began in 1972, when the RAND Corporation published a serious study of a coast-to-coast underground vactrain, and accelerated when Elon Musk's 2013 Hyperloop white paper rebranded the concept for the venture-capital era. A flurry of startups followed; most are now bankrupt or pivoting. Virgin Hyperloop conducted the only human test in 2020 — two passengers, 500 metres, 100 mph — and laid off most of its staff two years later. The physics remains sound. The economics, the safety case, and the geopolitics of digging a thousand-mile vacuum chamber across earthquake country remain very much not.

And yet the dream persists, because the math is genuinely seductive: a vactrain to London under the Atlantic would, on paper, take about 54 minutes — faster than most subway commutes within a single city.