PNEUMATIC TUBE SYSTEMS
HISTORY

The first street tube to be laid in London was put into service in 1853 by the International Telegraph Company through their engineer, Mr. Latimer Clark.  It ran from the Telegraph Centre to the Stock Exchange. In 1870, Dr. C. Siemens completed work for the Post Office on tubes to Charing Cross and Temple Bar and Mr. Varley, whose name was given to the standard test for line faults, was responsible for the introduction, in 1858, of compressed air working.

By 1875 the Post Office was operating in London 25 tubes totaling nearly 18 miles m length and all except those installed by Siemens were of lead.  Siemens used iron, but the rust problem seems to have been serious and eventually to have caused lead to be adopted as the standard material.

An unusual sidelight on the faulting practice of the 1870's is provided by two methods advocated for dealing with carriers which had jammed. In Paris the position of such carriers was determined by firing a pistol near the mouth of the tube and timing the period that elapsed before the echo was heard. Half this time multiplied by the velocity of sound gave the distance to the fault. The excitement of the method was doubtless one of its attractions for the volatile Parisians.  In this country the method was even more drastic. Each tube was provided with a connection to the water main and when a blockage occurred it was cleared by flooding the tube and using the mains pressure to force the carrier past the obstruction. No details are available of the use made of the device, but it is not difficult to imagine some amusing repercussions.

It is also interesting to note that in the United States Post Office Department put into service the first of a number of 6in. diameter tubes for the transmission of mails. Prior to this, pneumatic street tubes had only been used successfully for telegrams and the like. By 1908, 150 tons of mail (or 17 per cent. of the total weight) was moved each day by U.S. tubes at a speed of about 30 miles per hour, and by 1918 8in. diameter tubes were in use and were favorably reported upon. ·

Almost from the beginning two sizes of street tube were standard in this country, viz. 2.25in. and 3in. diameter and there is little difference between the standard construction methods employed to-day and those of 50 years ago. In fact some of the tubes installed under the City streets about 1880 are still in use. The system working from the Central Telegraph Office now comprises some 70 tubes with lengths up to 2.5 miles.

The London pneumatic street tube system was out of use after the destruction of the Central Telegraph Office in 1940 and the damage, by enemy action in WW2, which it sustained during the years that followed accumulated, until in 1943 it was found that it would be a major task to make the tubes fit to carry traffic.

Before reconditioning and repair work could be started a complete survey and considerable testing was essential and the opportunity was taken to include some tests of a fundamental character.

Last revised: December 30, 2023