TL;DR
The great tunnels of the next decade are being dug right now: a new rail line under the Hudson, a concrete tube laid piece by piece on the floor of the Baltic, a 2030s railway beneath the Alps. But the machines that dig them have become a pressure point. From Nov. 18 China will require export licences for tunnel boring machines, the same kind of lever it has used on rare earths, and India, which imports many of them, answered within days that it will build its own. For anyone waiting on a faster train or a new subway line, the timeline now depends on trade policy as much as on rock and concrete.
Below the line, for paid subscribers: The full story: where it stands, how we got here and what's dated next; our Odds board on 5 milestones, starting with "The second Hudson boring machine starts digging by 2026"; and every source.