Pneumatic tubes (or capsule pipelines; Lamson tubes) are systems in which cylindrical containers are propelled through a network of tubes by compressed air or by vacuum. They are used for transporting solid objects, as opposed to more generic pipelines, which transport gases or 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 Some of these systems grew to great complexity, but they were eventually superseded by more modern methods of communication and courier transport, and are now much rarer than before.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.
Pneumatic capsule transportation was originally invented by Phineas Balk in 1806. 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 1800s for transport of heavy freight. It was once envisioned that networks of these massive tubes might be used to transport people.
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 While its use for communicating information has been completely superseded by electronic systems, pneumatic tubes are still widely used for transporting small valuable objects, or where convenience and speed in a local environment is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.
In Britain, the House of Commons telephone and computer exchange also has a pneumatic tube system in place.
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 1800s and was later developed by the London Pneumatic Dispatch 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 mothballed indefinitely.
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.
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:
In 1861, the Pneumatic Despatch Company built a system large enough to move a person, although it was intended for parcels. The October 10, 1865 inauguration of the new Holborn Station 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 Whitehall Pneumatic 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.
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.
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.
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 20th 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". (In the same year of writing as Orwell's book (1949) Robert A. Heinlein's 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.
In 1985, the movie Brazil, which has similar themes to Nineteen Eighty-Four, 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 the devilish Mr. Roarke via a pneumatic tube from a dusty old travel agency, making the tube seem not so much bureaucratic as sinister.
The failure of pneumatic tubes to live up to their potential as envisioned 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 spit 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 the American television show Lost, The DHARMA initiative research Pearl 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.