You guys started me down this technological rat hole
There are plenty of engineering seeds for Verne’s idea—
Joining is left vague in proposals like Col. Pierce (he seems to be a bit of a P.T. Barum) –his proposal was to cross san fransciso bay about 4 miles
In 1861 to 1890 there were some short range pneumatic people systems but these were too rigid for across the Atlantic tube
Verne’s futuristic design
Verne’s design would at least have the strength and flexibility but joining is vague except some type of “screw system.”
Here some notes on 1861 london tube
1861 Trial Puematic tube
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“In the summer of 1861 passengers on the steamboat to Chelsea watched with interest the experiments held on the bank of the Thames. Near the open quay which adjoined the premises of the Southwark and Vauxhall Waterworks near Battersea pier they could, see exiting
an engine house, about 450 yards (0.4km) of black, iron tubing half sunk in the ground. First taking a winding turn, it then followed the bank of the river. Through the 2’ 9” (759mm) high and 2’ 6” wide (836mm) iron tube, four-wheeled carriers were blown.
The Pneumatic Despatch Company built an experimental tube on the banks of the Thames at Battersea, adjacent to the Victoria railway bridge. Illustration from The Illustrated London News, 24 August 1861
The tube itself was formed of sections of cast iron, nine feet (2.74m) long, nearly an inch (25mm) in thickness. Each was cast in one piece, weighed about a ton (907kg) and resembled a D lying on its side. Sections were fitted into each other with a socket
joint packed with lead.
Quent socket lead joint goes back to the Roman bridge builders –it would not be feasible for transatlantic tube construction
Within the tube were cast raised ledges 2″ (51mm) wide and 1″ (25mm) high. These formed the rails on which the carriages