New York’s Pneumatic Transport
Pneumatic technology powers the movement of solid objects through enclosed channels using air as a medium. Pipeline conveying systems transport loose bulk material, such as grains or powders, at industrial plants and construction sites. Tube systems with capsule carriers deliver documents and packages at institutional and commercial facilities, including hospitals, retail stores and drive-through banks. Miles of underground pipes once sent mail speeding through city-scale networks.
Lamson Tubes
In the 1880s William Stickney Lamson of Lowell, Massachusetts began manufacturing mechanical cash railway systems for retail stores. The Lamson Company first provided gravity propelled carriers on rail or wire lines that connected sales counters with back-room cash offices. Developing into an international supplier serving department stores and businesses, Lamson became famous for its pneumatic systems “for conveying papers and merchandise.” In 1911 the New York Public Library opened its main branch, at 42 Street and 5th Avenue, with a network of 3-inch Lamson tubes running call slips through its seven floors of stacks. A similar pneumatic system is installed at the NYPL Science, Industry and Business Library, which opened in 1998.
The Pneumatic-Tube Postal System
Application of pneumatics for purposes of transport appeared in the early nineteenth century. In London in 1810, mechanical engineer and manufacturer George Medhurst proposed in a pamphlet, “A new method of conveying letters and goods with great certainty and rapidity by air.” This alternative to wheeled and waterborne modes was realized by J. Latimer Clark, a civil engineer working on submarine telegraphy, with a patent for “conveying letters or parcels between places by the pressure of air and vacuum.” In 1853 Clark had the first pneumatic tube system constructed in London, a 675-foot pipeline from the central telegraph office to the stock exchange.
On this success the London postal service developed an underground network of 3-inch diameter tubes linking telegraph and post offices that enabled quick delivery of telegrams and letters. Other British and European cities adopted pneumatic mail systems, notably Berlin (1865), Paris (1866), Vienna (1867) and Prague (1899). London’s network grew to 75 total miles by the 1930s. The 280-mile Paris poste pneumatique—in operation through 1984—was able to route carriers automatically. The 37-mile Prague system continued service the longest, until 2002. After visits to investigate European systems in 1873, Western Union Telegraph introduced commercial pneumatic tube service in the United States.
In 1892 the U.S. Postmaster General received congressional approval “to examine into the subject of a more rapid dispatch of mail matter between large cities and post-office stations and transportation terminals located in large cities by means of pneumatic tubes.” A half- mile test line was implemented in Philadelphia the following year under contract with the Pneumatic Transit Co. of New Jersey. Large double 6-inch tubes routed first-class letters back and forth between the central post office and the East Chestnut Street (Bourse) branch. In 1897 the Post Office initiated development of a more extensive underground system in Philadelphia on a provisional basis, followed by the opening of tube service in New York, Boston, Chicago and St. Louis. Plans for pneumatic mail lines in Baltimore, Cincinnati, Kansas City, Pittsburgh and San Francisco were never implemented.
The underground pneumatic tube system of the New York Post Office began operation on October 15, 1897 and continued until 1953. Officially known as postal route 507011A, in 1950 it consisted of 27 miles of two-way lines, connecting the General Post Office at 33rd Street and 8th Avenue with 21 local offices in Manhattan and the Brooklyn General Post Office. The system expedited transmission of first-class and special delivery mail inbound, outbound and within the city as an alternative to surface transport through congested daytime traffic. With 17 hours of operation daily Monday through Friday, plus Saturday morning service 5 to 10 A.M., about six million pieces of mail per day traveled by tube. Cast-iron pipes 8 inches in diameter were buried 3 to 10 feet below streets, at times within or below subway tunnels, and went above ground along the cables of the Brooklyn Bridge.
About 140 postal employees operated a store of approximately 1,600 carriers that could be dispatched one every twelve seconds. Steel cylinder carriers 24 inches long could carry roughly 400 letters and weighed 30 pounds when full. An originating carrier would be filled with bundled letters or small parcels from a door at one end of the cylinder, labeled and launched. When it landed on the receiving apron at the next station it would be checked and sent on until its marked destination was reached. An average of 95,000 carriers were handled daily. Test carriers were circulated before beginning service every morning, and perforated decoy cylinders containing oil were sent out regularly to lubricate the cast iron.
The Post Office Department leased the physical infrastructure of New York’s pneumatic tube system annually from a contracted corporation. The New York Mail and Newspaper Transportation Company, owned by the American Pneumatic Tube Service Co., installed and maintained pipe, machinery and power plants for the greater extent of the system’s history. Segments of pipeline were aligned with spigot-and-socket joints and fastened with a bolted flange. Transmitter and receiver apparatus at each station sent, accepted and relayed carriers from one point to the next. 11 stations housed electric generators that powered rotary blowers and air compressors, which regulated velocity at 30 miles an hour.
By the 1950s the relatively low cost of trucking mail superseded the substantial expenses of leasing and powering a pneumatic system. The Postmaster General suspended tube service in Manhattan indefinitely on December 12, 1953. Service to Brooklyn had been discontinued the previous year when pipelines were removed for bridge reconstruction.
Transporting mail by pneumatic tube was more successful in New York than any other city in the U.S. A 1949 evaluation of the system found that 60% of mail was handled during hours of pneumatic service, 50% of which was then dispatched underground. The high volume of mail combined with the slow rate of truck travel through the city made the system a valuable auxiliary. Travel by tube was estimated to be 2-1/2 times faster than motor vehicle service in the areas where tubes were in operation. Pneumatic service was suspended in all cities for congressional review beginning in 1919, and was reinstated only in New York in 1922 and Boston in 1926.
