New York also used pneumatic tubes for the postal service, but they were replaced with mail-trucks. My understanding is that the empty tubes themselves have bee

New York also used pneumatic tubes for the postal service, but they were replaced with mail-trucks. My understanding is that the empty tubes themselves have been repurposed to carry fiber-optics cables for trading firms and the like. Heck, the first New York City subway (the Beach Pneumatic Railway) (a) was pneumatic (b) was an abuse of a permit to build a pneumatic tube under Broadway. There were also open-air pneumatic railways ("atmospheric railways") in a few places, including in the UK -- they used a piston in a small tube to drive the car from underneath, sort of like a cable car ... but they didn't have good rubber, had to rely on leather seals that were plagued with inflexibility and rat problems. Then they invented the electrical multiple-unit train... bo-ring. :b