There's plenty going on in terms of establishing more high-speed rail networks within the United States, and we see plenty of monorails at airports. Experimentation also continues with new technologies such as maglev trains that float to their destinations on magnetically charged runways. Of course, places such as Japan have had high-speed rail since the bullet trains began running in the 1960s.
But a novel approach was first attempted under the streets of New York, and may have even caught on if not for politics and an economic crisis that dried up funding. As far back as 1870, Alfred Ely Beach demonstrated and opened a subway line under Broadway that employed a large pneumatic tube to propel riders. Trains would be swished from stop to stop by air pressure, just as documents in plastic capsules are whisked around buildings or to bank tellers at drive-ins.
Wired ran this account of Beach's project on the 140th anniversary of the line's first launch, and there is a wealth of information maintained by Joseph Brennan at the Columbia University Website -- and lots of great illustrations.
As accounts have it, Beach constructed a tubular subway and station, with a train powered by a massive air blower at one end. The line ran for a couple of years, but Beach apparently had powerful interests arrayed against him -- and support from the state was vetoed. The Long Depression of the 1870s furthered curtailed his plans, and the tunnel was eventually closed.
The pneumatic-tube line built by Beach may have been centuries ahead of its time. Gravity-vacuum transit remains a mode that still entices thinkers looking for more efficient ways to move people from point to point. We have the big-budget government projects (such as $8 billion for high-speed rail), but perhaps the world needs more entrepreneurial thinkers and doers such as Alfred Beach to bring new concepts to reality.
(Trivia: the Beach Pneumatic Transit line was the inspiration for the band Klaatu's 1977 hit, "Sub-Rosa Subway." I first thought the concluding lyrics were "..it runs in tubes," which makes total sense, and hence, the inspiration for title to this article. It was only years later I found out the final lyrics were actually "to Brahmsian tunes." )