The Future of Sucking, Part II--Supersonic Travel Tunnel

JF Ptak Science Books    Post 2090 (continuing an earlier post)

I found a report by John Prather in 1945 continues a sluggish history of underground high-speed travel. There's a scifi story by Jules Verne's son, Michael, Un Express de l'avenir (An Express of the Future), written in 1888, and a 1913  novel Der Tunnel by Bernhard Kellermann, and a very pretty example, a New York-Los Angeles bullet train as found in Modern Mechanix in 1948:

There's also a very fine effort described in the wonderful Improbable Research website, an 1825 effort, describing a 5-minute ride from London to Edinburgh.

John B. Prather launched an idea in 1945 for building a high-speed pneumatic passenger/freight train connecting New York City to Philadelphia.  His New York-Philadelphia Vacuum Tunnel, Preliminary Design Features and Economic Analysis (the original available on our blog bookstore) was exceptionally hearty. The idea is interesting in a removed, lets-not-do-it way because, well, it just doesn't seem to make sense in the long run, at least beyond the building of the thing to show that it could be done.  And I don't doubt that could be the case--I just don't know why it was necessary. 

Mr. Prather's approach seems to be the work of an engineer, or at least he had some help.  I doubt though that he had any help from a structural engineer or site geologist--his 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. 

I don't see, really, how this could be so narrow a tunnel--I'm not an engineer but it would seem that wear, heat and the abuse and so on that a massive and dense 400'-long missile going 400+mph would require something that was more than 125% of the width of its trains. 

There is however  precedence for a massive tunnel of something like this size being built in something like this time--the Delaware Aqueduct is 82 miles long and 13 feet wide, and was built during the Second World War (1939-1945) , so, perhaps if enough people and money were thrown at a project like the vacuum tunnel could actually be built (barring geological problems). 

But it would all be worth it:  Prather suggests that the overall revenue from the operation of the train to be $196 million/year with $32 million in yearly operating expenses.  Which means that the whole thing could be paid for in three years or thereabouts.  So if the things was started in 1946, it would all be finished and paid for by 1956.

I can understand his thinking, though, especially when you consider the impact of the year (1945) in which this paper was written.  The U.S. was came away from WWII by far more strong than any country on Earth, with its GDP being about 50% of that of the entire world--on the other hand, the federal deficit was 125% of the GDP, so perhaps in addition to being in an extraordinary position, investment was also somewhat gunshy.  And of course there's the problem of whether Prather's idea made any sense at all.  But I can understand the high times during which his project was announced. 

I've looked at a number of proposals like this over the course of this blog--like almost filling up the Narrows between Staten Island and Manhattan with an airport and seaport, and making a series of transoceanic airports for flights between the continents, and dropping a gigantic shell filled with people from the top/interior of the Eiffel into a narrow hole filled with water, and covering Midtown Manhattan with a rooftop airport, and covering Midtown Manhattan with a glass-ish dome, and so on--and I know that it is good for at least one thing:  superb classroom discussion fodder of why something like this does or doesn't make good physical/economic etc. sense.

 

 

Comments

[John McKay]

I like the Modern Mechanix train. We need more bubble canopies on things.

[Jeff Donlan]

I agree with Mr. McKay -- bubble canopies are cool. Especially two. Also, what is the proposed propulsion? I presume the vacuum is to precede the train and reduce wind resistance, but something else is needed to get to 400 mph.