Pneumatic tubes (or capsule pipelines; also known as Pneumatic Tube Transport or PTT) are systems in which cylindrical containers are propelled through a network of tubes by compressed air or by partial vacuum. They are used for transporting solid objects, as opposed to conventional pipelines, which transport fluids. Pneumatic tube networks gained great prominence in the late 19th and early 20th century for businesses or administrations that needed to transport small but urgent packages (such as mail or money) over relatively short distances (within a building, or, at most, within a city). Some of these systems grew to great complexity, but they were eventually superseded by more modern methods of communication and courier transport, and are now much rarer than before. However, in some settings, such as hospitals, they remain of great use, and have been extended and developed further technologically in recent decades.
A small number of pneumatic transportation systems were also built for larger cargo, to compete with more standard train and subway systems. However, these never gained as much popularity as practical systems.
Historical use 
Pneumatic capsule transportation was originally invented by William Murdoch. Though a marvel of the time, and a successful sideshow, it was considered little more than a novelty until the invention of the capsule in 1836. The Victorians were the first to use capsule pipelines to transmit telegraph messages, or telegrams, to nearby buildings from telegraph stations.
While they are commonly used for small parcels and documents – now most often used as cash carriers at banks or supermarkets – they were originally proposed in the early 19th century for transport of heavy freight. It was once envisaged that networks of these massive tubes might be used to transport people.
Current use 
The technology is still used on a smaller scale. While its use for communicating information has been completely superseded by electronic systems, pneumatic tubes are still widely used for transporting small valuable objects, or where convenience and speed in a local environment is useful.
In the United States, a large number of drive-up banks use pneumatic tubes to transport cash and documents between cars and tellers. Most hospitals have a computer-controlled pneumatic tube system to deliver drugs, documents and specimens to and from laboratories and nurses' stations. Many factories use them to deliver parts quickly across large campuses. Many larger stores use systems to securely transport excess cash from checkout stands to back offices, and to send change back to cashiers. NASA's original Mission Control Center in Houston, Texas had pneumatic tubes connecting controller consoles with staff support rooms. Denver International Airport is noteworthy for the large number of pneumatic tube systems, including a 25 cm diameter system for moving aircraft parts to remote concourses, a 10 cm system for United Airlines ticketing, and a robust system in the parking toll collection system with an outlet at every booth.
Pneumatic tube systems are used in science, to transport samples during neutron activation analysis. Samples must be moved from the nuclear reactor core, in which they are bombarded with neutrons, to the instrument that records the resulting radiation. As some of the radioactive isotopes in the sample can have very short half-lives, speed is important. These systems may be automated, with a magazine of sample tubes that are moved into the reactor core in turn for a predetermined time, before being moved to the instrument station and finally to a container for storage and disposal.
Until it closed in early 2011, a McDonald's in Edina, Minnesota claimed on its receipts to be the "World's Only Pneumatic Air Drive-Thru," sending food from their strip-mall location to a drive-through in the middle of a parking lot.
In postal service 
Pneumatic post or pneumatic mail is a system to deliver letters through pressurized air tubes. It was invented by the Scottish engineer William Murdoch in the 19th century and was later developed by the London Pneumatic Despatch Company. Pneumatic post systems were used in several large cities starting in the second half of the 19th century (including an 1866 London system powerful and large enough to transport humans during trial runs – though not intended for the purpose), but were largely abandoned during the 20th century.
It was also speculated that a system of tubes might deliver mail to every home in the US. A major network of tubes in Paris was in use until 1984, when it was finally abandoned in favor of computers and fax machines. In Prague, in the Czech Republic, a network of tubes extending approximately 60 kilometres in length still exists for delivering mail and parcels. Following the 2002 European floods, the Prague system sustained damage, and operation was halted until recently when Czech start up Lime & Tonic revived the Prague pneumatic postal system to integrate their reservations system with their merchants.
Pneumatic post stations usually connected post offices, stock exchanges, banks and ministries. Italy was the only country to issue postage stamps (between 1913 and 1966) specifically for pneumatic post. Austria, France, and Germany issued postal stationery for pneumatic use.
- Historical use
- 1853: linking the London Stock Exchange to the city's main telegraph station (a distance of 220 yards (200 m) )
- 1861: in London with the London Pneumatic Despatch Company providing services from Euston railway station to the General Post Office and Holborn
- 1865: in Berlin (until 1976), the Rohrpost, a system 400 kilometers in total length at its peak in 1940
- 1866: in Paris (until 1984, 467 kilometers in total length from 1934)
- 1875: in Vienna (until 1956)
- 1887: in Prague (until 2002 due to flooding), the Prague pneumatic post
- 1897: in New York City (until 1953)
- other cities: Munich, Rio de Janeiro, Buenos Aires, Hamburg, Rome, Naples, Milan, Marseille, Melbourne, Boston, Philadelphia, Chicago, St. Louis
In public transportation 
- 19th century
In 1812, George Medhurst first proposed, but never implemented, blowing passenger carriages through a tunnel. Precursors of pneumatic tube systems for passenger transport, the atmospheric railway (for which the tube was laid between the rails, with a piston running in it suspended from the train through a sealable slot in the top of the tube) were operated as follows:
- 1844–54: Dublin and Kingstown Railway's Dalkey Atmospheric Railway between Kingstown (Dún Laoghaire) and Dalkey, Ireland (1.75 mi (2.82 km))
- 1846–47: London and Croydon Railway between Croydon and New Cross, London, England (7.5 mi (12.1 km))
- 1847–48: Isambard Kingdom Brunel's South Devon Railway between Exeter and Newton Abbot, England (20 mi (32 km))
- 1847–60: Paris–Saint-Germain railway between Bois de Vésinet and Saint-Germain-en-Laye, France (2 km (1.2 mi))
In 1861, the London Pneumatic Despatch Company built a system large enough to move a person, although it was intended for parcels. The inauguration of the new Holborn Station on 10 October 1865 was marked by having the Duke of Buckingham, the chairman, and some of the directors of the company blown through the tube to Euston (a five-minute trip).
The 550-meter Crystal Palace pneumatic railway was exhibited at the Crystal Palace in 1864. This was a prototype for a proposed Waterloo and Whitehall Railway that would have run under the River Thames linking Waterloo and Charing Cross. Digging commenced in 1865 but was halted in 1868 due to financial problems.
In 1867 at the American Institute Fair in New York, Alfred Ely Beach demonstrated a 32.6 m long, 1.8 m diameter pipe that was capable of moving 12 passengers plus a conductor. In 1869, the Beach Pneumatic Transit Company of New York secretly constructed a 95 m long, 2.7 m diameter pneumatic subway line under Broadway, to demonstrate the possibilities of the new transport mode. The line only operated for a few months, closing after Beach was unsuccessful in getting permission to extend it – Boss Tweed, an immensely powerful local politician, did not want it to go ahead as he was intending to personally invest into competing schemes for an elevated rail line.
- 20th century
In the 1960s, Lockheed and MIT with the United States Department of Commerce conducted feasibility studies on a vactrain system powered by ambient atmospheric pressure and "gravitational pendulum assist" to connect cities on the East Coast of the US. They calculated that the run between Philadelphia and New York City would average 174 meters per second, that is 626 km/h (388 mph). When those plans were abandoned as too expensive, Lockheed engineer L.K. Edwards founded Tube Transit, Inc. to develop technology based on "gravity-vacuum transportation". In 1967 he proposed a Bay Area Gravity-Vacuum Transit for California that would run alongside the then-under construction BART system. It was never built.
- 21st century
Research into trains running in partially evacuated tubes is continuing. For further information see Vactrain.
Technical characteristics 
Modern systems (for smaller, i.e. "normal" tube diameters as used in the transport of small capsules) reach speeds of around 7.5 m (25 ft) per second, though some historical systems already achieved speeds of 10 m (33 ft) per second. Further, modern systems can also be computer-controlled, allowing, among other things, the tracking of any specific capsule. Varying air pressures also allow capsules to brake slowly, removing the jarring arrival that used to characterise earlier systems and make them unsuitable for fragile contents.
In fiction 
When pneumatic tubes first came into use in the 19th century, they symbolized technological progress and it was imagined that they would be common in the future. Jules Verne's Paris in the Twentieth Century (1863) includes suspended pneumatic tube trains that stretch across the oceans. Albert Robida's The Twentieth Century (1882) describes a 1950s Paris where tube trains have replaced railways, pneumatic mail is ubiquitous, and catering companies compete to deliver meals on tap to people's homes through pneumatic tubes. Edward Bellamy's Looking Backward (1888) envisions the world of 2000 as interlinked with tubes for delivering goods, while Michel Verne's An Express of the Future (1888) questions the sensibility of a transatlantic pneumatic subway. In Michel & Jules Verne's The Day of an American Journalist in 2889 (1889) submarine tubes carry people faster than aero-trains and the Society for Supplying Food to the Home allows subscribers to receive meals pneumatically.
Later, because of their use by governments and large businesses, tubes began to symbolize bureaucracy. In George Orwell's Nineteen Eighty-Four, pneumatic tubes in the Ministry of Truth deliver newspapers to Winston's desk containing articles to be "rectified". Robert A. Heinlein's 1949 novella Gulf offered a more neutral view of their use in general postal delivery.)
In a sequence from the 1968 film Baisers volés (Stolen Kisses), François Truffaut shows the fast transportation of a letter through the underground pneumatic tubes system in Paris. (This scene was later parodied in The Simpsons episode "Marge Gets a Job".)
In 1985, the movie Brazil also used tubes (as well as other anachronistic-seeming technologies) to evoke the stagnation of bureaucracy. At the start of each episode of the 1998 television series Fantasy Island, a darker version of the original, bookings for would-be visitors to the Island were sent to Mr. Roarke via a pneumatic tube from a dusty old travel agency.
The 1994 film version of The Shadow includes a sequence in which the camera follows a message capsule as it speeds through a pneumatic tube system. The implication is that the Shadow maintains a private network of tubes for the transportation of secret messages.
The failure of pneumatic tubes to live up to their potential as envisaged in previous centuries has placed them in the company of flying cars and dirigibles as ripe for ironic retro-futurism. The 1960s cartoon series The Jetsons featured pneumatic tubes that people could step into and be sucked up and swiftly spat out at their destination. In the animated television series Futurama, set in the 31st century, large pneumatic tubes are used in cities for transporting people, whilst smaller ones are used to transport mail. The tubes in Futurama are also used to depict the endless confusion of bureaucracy: an immense network of pneumatic tubes connects all offices in New New York City to the "Central Bureaucracy", with all the capsules being deposited directly into a huge pile in the main filing room, with no sorting or organization.
In Ghostbusters II, the "river of slime" under New York city is found by the Ghostbusters boys to be flowing through an old pneumatic tube line – a reference to the Beach Pneumatic Transit tube.
In the 1998 PC game Grim Fandango, Pneumatic tubes play a role in the part of the story that takes place at Manny's office.
In the American television show Lost, the DHARMA Initiative's Pearl research station has a pneumatic tube system. The character Locke put his drawing of the blast door map in the tube without a capsule. It was sucked up into the tube, indicating the system still functioned. The tube from the Pearl leads to a capsule dump.
In Kurt Vonnegut's Slaughterhouse-Five pneumatic tubes are used as a way to transport information from one place to the next when covering news articles.
In the popular video game Bioshock, pneumatic tubes are used to transport various items throughout the fictional city of Rapture. In Portal and Portal 2, two other popular games, Aperture Science uses Pneumatic tubes to transport larger-scale objects such as boxes of all kinds throughout their enrichment center.
Douglas Adams's 1998 computer game Starship Titanic features the "Succ-U-Bus" in almost every room – being a pneumatic pipe transport system which goes all around the ship; players must understand and use the Succ-U-Bus in order to progress and solve the puzzles. Umberto Eco in his novel The Prague Cemetery has one character, Simonini, send a "petit blue message by pneumatic post". Presumably these messages were on small pieces of blue paper.
See also 
- Pipeline transport
- Prague pneumatic post, the world's last preserved pneumatic mail system
- Garbage collection
- Lamson Engineering Company Ltd
- "Gone with the wind: Tubes are whisking samples across hospital". Stanford School of Medicine. 2010-01-11. Retrieved 12 February 2010.
- Buxton, Andrew (2004). Cash Carriers in Shops. Princes Risborough: Shire Publications. ISBN 978-0-7478-0615-8.
- Becker, D.A. (22 June 10, 1998). "Characterization and use of the new NIST rapid pneumatic tube irradiation facility". Journal of Radioanalytical and Nuclear Chemistry 233: 155–160.
- "Pneumatic Air Drive-Thru McDonald's". Waymarking website. Retrieved 12 February 2010.
- "Czech start wins 19th century technology". Retrieved 12 February 2010.
- "Prague's pneumatic post". Telefónica O2 Czech Republic. 2002. Archived from the original on 2010-01-09. Retrieved 12 February 2010.
- George Medhurst, Calculations and remarks tending to prove the practicability ... of a plan for the rapid conveyance of goods and passengers upon an iron road through a tube of 30 feet in area, by the power and velocity of air, London: 1812
- Hadfield, Charles (1967). Atmospheric Railways. Newton Abbot: David & Charles. ISBN 0-7153-4107-3.
- Allen, Oliver E. "New York's Secret Subway". AmericanHeritage.com website. Retrieved 12 February 2010.
- "Capsule Pipelines – Mainland Europe". Capsu.org website. Retrieved 12 February 2010.
- Bellamy, Edward (1888). [[Looking Backward]], Chapter X. Wikilink embedded in URL title (help)
- Verne, Michel (1888). An Express of the Future.
- Verne, Jules; Verne (1889). The Day of an American Journalist in 2889. Michel.
London Midland Magazine – February 1963 – article on the Pneumatic Dispatch Railway in London
|Wikimedia Commons has media related to: Pneumatic tube|
- Site describing Pneumatic Trash and Linen Systems, with photos
- Describes Paris pneumatic post, also mentions others
- Dial Switches Message Tubes 1951 article that describes with photos and drawing the basics of how the system operates
- Site describing pneumatic post systems in England, France, Berlin, the US, and Prague, with photos
- Article describing the pneumatic post system in Prague
- Pneumatic mail article from the U.S. National Postal Museum
- The pneumatic dispatch... (1868) by Alfred Beach (scanned pages)
- Beach Pneumatic Alfred Beach's Pneumatic Subway and the beginnings of rapid transit in New York
- Futuristics: Pneumatic Transportation (contains historical illustrations)
- Capsule Pipelines: includes extensive historical documentation
- Components of a pneumatic tube system
- Archibald Williams, "Pneumatic Mail Tubes". Complete description and history in ordinary language. In The Romance of Modern Mechanism: With Interesting Descriptions in Non-Technical Language of Wonderful Machinery and Mechanical Devices and Marvellously Delicate Scientific Instruments, Etc., Etc. Philadelphia: Lippincott, 1907. Reprinted by Nabu Press, 2010. ISBN 1-146-99537-7.
- Pneumatic Tube System - How it works