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Vactrain
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Vactrain
A vactrain (or vacuum tube train) is a proposed design for very-high-speed rail transportation. It is a maglev (magnetic levitation) line using partly evacuated tubes or tunnels. Reduced air resistance could permit vactrains to travel at very high (hypersonic) speeds with relatively little power—up to 6,400–8,000 km/h (4,000–5,000 mph). This is 5–6 times the speed of sound in Earth's atmosphere at sea level.
In 1799, George Medhurst of London conceived of and patented an atmospheric railway that could convey people or cargo through pressurized or evacuated tubes. The early atmospheric railways and pneumatic tube transport systems (such as the Dalkey Atmospheric Railway) relied on steam power for propulsion.
In 1888, Michel Verne, son of Jules Verne, imagined a submarine pneumatic tube transport system that could propel a passenger capsule at speeds up to 1,800 km/h (1,100 mph) under the Atlantic Ocean (a transatlantic tunnel) in a short story called "An Express of the Future".
The vactrain proper was invented by Robert H. Goddard as a freshman at Worcester Polytechnic Institute in the United States in 1904. Goddard subsequently refined the idea in a 1906 short story called "The High-Speed Bet", which was summarized and published in a Scientific American editorial in 1909 called "The Limit of Rapid Transit". Esther, his wife, was granted a US patent for the vactrain in 1950, five years after his death.
In 1909, Russian professor Boris Weinberg built the world's first model of his proposed version of the vactrain at Tomsk Polytechnic University. He later published a vactrain concept in 1914 in the book Motion without friction (airless electric way).
In 1955, in his novel The Magellan Nebula, Polish science-fiction writer Stanisław Lem wrote about an intercontinental vactrain called "organowiec", which moved in a transparent tube at a speed higher than 1,666 km/h (1,035 mph). In April 1962, the vactrain appears in the story "Mercenary" by Mack Reynolds, where he mentions Vacuum Tube Transport in passing.
During the 1970s, a leading vactrain advocate, Robert M. Salter of RAND Corporation, published a series of elaborate engineering articles.
An interview with Robert Salter appeared in the Los Angeles Times (June 11, 1972). He discussed, in detail, the relative ease with which the U.S. government could build a tube shuttle system using technologies available at that time. Maglev being poorly developed at the time, he proposed steel wheels. The chamber's door to the tube would be opened, and enough air admitted behind to accelerate the train into the tube. Gravity would further accelerate the departing train down to cruise level. Rising from cruise level, the arriving train would decelerate by compressing the rarefied air ahead of it, which would be vented. Pumps at the stations would make up for losses due to friction or air escaping around the edges of the train, the train itself requiring no motor. This combination of modified (shallow) gravity train and atmospheric railway propulsion would consume little energy but limit the system to subsonic speeds, hence initial routes of tens or hundreds of miles or kilometers rather than transcontinental distances were proposed.
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Vactrain
A vactrain (or vacuum tube train) is a proposed design for very-high-speed rail transportation. It is a maglev (magnetic levitation) line using partly evacuated tubes or tunnels. Reduced air resistance could permit vactrains to travel at very high (hypersonic) speeds with relatively little power—up to 6,400–8,000 km/h (4,000–5,000 mph). This is 5–6 times the speed of sound in Earth's atmosphere at sea level.
In 1799, George Medhurst of London conceived of and patented an atmospheric railway that could convey people or cargo through pressurized or evacuated tubes. The early atmospheric railways and pneumatic tube transport systems (such as the Dalkey Atmospheric Railway) relied on steam power for propulsion.
In 1888, Michel Verne, son of Jules Verne, imagined a submarine pneumatic tube transport system that could propel a passenger capsule at speeds up to 1,800 km/h (1,100 mph) under the Atlantic Ocean (a transatlantic tunnel) in a short story called "An Express of the Future".
The vactrain proper was invented by Robert H. Goddard as a freshman at Worcester Polytechnic Institute in the United States in 1904. Goddard subsequently refined the idea in a 1906 short story called "The High-Speed Bet", which was summarized and published in a Scientific American editorial in 1909 called "The Limit of Rapid Transit". Esther, his wife, was granted a US patent for the vactrain in 1950, five years after his death.
In 1909, Russian professor Boris Weinberg built the world's first model of his proposed version of the vactrain at Tomsk Polytechnic University. He later published a vactrain concept in 1914 in the book Motion without friction (airless electric way).
In 1955, in his novel The Magellan Nebula, Polish science-fiction writer Stanisław Lem wrote about an intercontinental vactrain called "organowiec", which moved in a transparent tube at a speed higher than 1,666 km/h (1,035 mph). In April 1962, the vactrain appears in the story "Mercenary" by Mack Reynolds, where he mentions Vacuum Tube Transport in passing.
During the 1970s, a leading vactrain advocate, Robert M. Salter of RAND Corporation, published a series of elaborate engineering articles.
An interview with Robert Salter appeared in the Los Angeles Times (June 11, 1972). He discussed, in detail, the relative ease with which the U.S. government could build a tube shuttle system using technologies available at that time. Maglev being poorly developed at the time, he proposed steel wheels. The chamber's door to the tube would be opened, and enough air admitted behind to accelerate the train into the tube. Gravity would further accelerate the departing train down to cruise level. Rising from cruise level, the arriving train would decelerate by compressing the rarefied air ahead of it, which would be vented. Pumps at the stations would make up for losses due to friction or air escaping around the edges of the train, the train itself requiring no motor. This combination of modified (shallow) gravity train and atmospheric railway propulsion would consume little energy but limit the system to subsonic speeds, hence initial routes of tens or hundreds of miles or kilometers rather than transcontinental distances were proposed.