In spy war-themed movies, there is often such a "magical information transmission scene": the contact person puts the top-secret information into a cylindrical capsule and quickly transmits the information to the recipient through a pipeline. For example, in the "Fast Pursuit" series starring Keanu Reeves, the killer group issued a pursuit warrant in this way. This "black technology" of pneumatic transmission pipelines is not a movie fiction, they have been widely used since the first industrial revolution, and based on this technology, New York has also created a large and complex postal system.
According to the American magazine "Smithsonian", the pneumatic transmission piping system was created by the Scottish inventor and mechanical expert William Murdoch in the early 19th century, and its working principle is to use air pressure to push objects from one end of the pipe to the other, and the transmission efficiency at that time was far greater than that of manual and horse-drawn carriages. However, the application scenarios of this technology are limited, and it is only suitable for conveying small objects over short distances, such as important documents, cash, etc.
In the Victorian period of England, this type of pipe was used to transmit telegraphs: in 1853, a pneumatic pipeline connected the London ** Exchange and the British Telegraph Company, so that the latter could get the latest financial information as soon as possible, and then pass it on to those who subscribed to the financial information service.
At the end of the 19th century, the pneumatic transmission system was "carried forward" by the Americans who pursued efficiency, and many cities in the United States prepared to build a "pipeline mail" system, including Chicago, Boston, Philadelphia, etc. New York City has the most well-developed piping system, and in Manhattan, pneumatic transmission pipes buried underground form a "loop" that almost covers the entire area, connecting 22 post offices. There is also a "feeder line" that connects the General Post Office in Lower Manhattan with Brooklyn. In October 1897, Chauncey Deep, a Republican congressman from the United States, presided over the unveiling ceremony of New York's "pipeline mail" system, saying that "speed determines happiness and civilization" and "the success or failure of New York depends on efficient and fast communication".
During the first test run of the system, Deepp sent a parcel from the New York Post Office to the New York Agricultural Exchange, containing a Bible wrapped in an American flag, a copy of the U.S. Constitution, and a few other items. The distance between the two places is about 2 kilometers, and it takes less than 3 minutes to reach the destination after the package is delivered. Then, people tried to mail other items with great interest, including clothing, candlesticks, and fragile items such as champagne and eggs, and even mailed a black cat, all of which arrived at their destination intact, but the black cat looked a little "dizzy" when it arrived, and the experiment was a great success.
Since then, the "Pipeline Post" has been operating in New York for half a century, with a total length of about 43 kilometers and millions of letters and parcels "sent" every day. In order to accommodate the size of the pipe, all mail should be able to be packed in a cylindrical capsule 60 cm long and 20 cm in diameter. The container weighs about 20 pounds, can hold 400 letters at a time, and can travel at speeds of up to 30 kilometers per hour in the pipeline. At peak times, the postal system delivers an average of one package every six seconds.
The New York Times reported that sending a letter inside a pipeline is actually a lot like "firing a gun", the capsule is fast, it gets a little hot when it arrives at its destination, and there is a layer of lubricating oil on its surface to ensure that the package is not bothered by friction. The shipping operators at that time were figuratively called "rocket launchers". By the mid-20s, as many as 55 percent of all mail in New York was sent and received through these pipes, and road transmission was the second option.
However, the development of the "Pipeline Post" has not been smooth sailing, and the facility, which is buried between 1 and 5 meters underground, will inevitably have technical failures. In February 1898, a capsule containing a large number of letters accidentally cracked in the middle of delivery, and more than 600 letters were destroyed. In March of the same year, a pipeline was shut down due to its damp location. Many in the U.S. Congress began to question the efficiency of the "pipeline post", and between 1901 and 1902, Congress stopped allocating funds to operators, resulting in a complete shutdown of the pipeline system. In 1903, the pipeline system, which had just resumed operation, caused another fatality: two maintenance workers went to clear a blockage in the pipeline, due to a misunderstanding, the mail operator sent ** package during the repair process, one was injured, and one unfortunately died.
During the First World War, the United States** once again completely suspended the "pipeline mail" business in order to save money. Because the cost of this service is staggering, the average cost per mile for a pipe hire alone (1 mile is about 1.).6 km) on up to 1$70,000, about $500,000 today, and that doesn't include labor costs, routine maintenance expenses, etc. After the end of World War I, only two cities, New York and Boston, resumed this service.
However, with the popularization of automobiles, road transportation has increased its transportation capacity, and pipeline transportation has completely lost its cost performance. The New York Postal Service did the math in the 50s of the last century, saying that the city only needs to add two postal trucks to completely replace the "pipeline post", because the operating cost of the former is only 2$50,000, the latter as much as $1 million. So at the end of 1953, the pneumatic transmission system ended its 56-year life and withdrew from the stage of history.
However, this set of "black technology" created in the steam age often appears in film and television works, creating a sense of mystery for the audience across the era. (Liu Haoran).