In an alternate universe, there's a 600-mph underground missile train between NYC and Philly

In John B. Prather's 1945 paper New York-Philadelphia Vacuum Tunnel, Preliminary Design Features and Economic Analysis, the author proposes building a screaming vacuum train that will blast between Philadelphia and NYC in 20 minutes. Up yours, New Jersey Turnpike!

Here are the details from John Ptak of Ptak Science Books:

[H]is proposal was to build this tunnel 100' down through bedrock when it could be found, a level hundred-feet below the surface, from NYC to Philadelphia. The tube would accommodate an aluminum-shelled 400'-long train that would be hauling 350 people and 175 tons of freight at speeds of 400-600+ mph, making the run between the two cities in about 20 minutes. Not bad. He figures too that all of the freight could be offloaded in 7.5 minutes. This would make for a very busy train, though Prather doesn't tell us how many runs a day it would be making. This was all preliminary.

The 16.2'-wide tunnel would be 456,720 feet long, and would cost $173 million to excavate and $41 million to line with cement—according to the author. The total cost for the ordeal would be about $334 million and would take 6 years, start to finish—that includes all of the tunneling, which would swallow/excavate/face 300' per day.

The train's terminals were Madison Avenue and 42nd Street in New York and Broad and Market in Philadelphia. It's unclear if Prather consulted a geologist (or at least got a second opinion from an engineer) on his schematics. Still, it's a project that deserves to be in the Annals of Weird Never-Was Mass Transit Projects. Read more about Prather's vacuum train here.