Senior Curator Julian describes the second experiment with the pneumatic tube system.

In the first part of this new blog series, I wrote about the beginnings of The Pneumatic Railway. This week I look at the second extension of the railway.

The Pneumatic Despatch Railway conducted initial trials of a sealed pneumatic railway, where carriages were moved under pressure of air, above ground at Battersea in 1861. Following these trials, the company lay an underground tube between the sorting room at the Post Office’s North West District Office (NWDO) at Eversholt Street to beneath Platform One of the London & North Western Railway at Euston Station. This first carried mails beneath the streets of London from 20 February 1863.

Various problems were encountered in the running of the railway and this first section had to be abandoned and last carried mail in October 1866. However, the company was not prepared to simply abandon their ambitions and pushed on with their an extension to their original plans. An application had been submitted to the Commissioners of Sewers of the City of London to lay a tube through Holborn, Skinner Street and Newgate Street- ‘to a station to be established at or near the end of the General Post Office in St. Martin’s-le-Grand’.

The large station at Holborn was the terminal for the second, larger pneumatic tube built by the Pneumatic Despatch Company

This second underground tube was of a larger size than the first, being increased to a height of 4’ and width of 4’ 6” (1219mm by 1372mm). Corresponding larger wheeled carriages were also introduced; the rail gauge for these was 3’ 8 ½” (1130mm). The Times reported on 20 November 1863 that the tube ran at a depth of between 11′ 6″ to 18’6″ (3.5m to 5.6m). Laying of the tube proceeded at a rate of 50 yards (46m) per day and construction caused great inconvenience to the public when the streets were opened up. Tenants on the Duke of Bedford’s estate protested and the tube was forced to be routed via the more circuitous route of Tottenham Court Road.

The Illustrated London News had reported on 18 November 1865 that the underground railway from Euston to Holborn measured a distance of 3080 yards (2816m). The new section extended a further 1685 yards (1541m) to the General Post Office in St. Martin’s-le-Grand. The tightest curve on the line was that approaching the Holborn pneumatic exchange station with a 70′ (21.3m) radius. Holborn station was described as being of a considerable size. A gallery looked down on a brick floor supporting lines of rails. White jacketed engineers operated the machinery, pushing the rail carriages and their loads into the mouths of the pneumatic tubes, afterward closing angled, iron folding doors to maintain the six ounces of pressure per square inch within (0.365psi). These doors opened on the approach of carriages by means of a spring lever underlying the rails that gave way under the weight of the train. Each carriage end had a raised hood or flange of india-rubber, a natural rubber harvested from the rubber tree, which was shaped to correspond with the shape of the inner surface of the tube. This provided the seal and enabled the carriages to be moved under air-pressure.

The engine room at Holborn was supplied with three Cornish boilers, each 30′ long and 6′ 6″ diameter (9.1m x 2m), supplying steam to a steam engine. This was fitted with a pair of 24″ cylinders with a 20″ stroke (610mm x 508mm). The engine drove a fan, similar to that at installed at Euston, but now measuring 22′ 6″ (6.86m) diameter.

A large crowd of interested onlookers observed the proceedings on the first day of operation of the second pneumatic railway built by the Pneumatic Railway Company. Illustration from The Illustrated London News supplement, 18 November 1865

On its opening day in 1865, various ‘scientific gentlemen’ were invited to attend and inspect the apparatus. Needless to say, having observed the successful passage of the railcars, the party were soon clamouring to be transported themselves, they were warned that the line had not been constructed with a view to passenger traffic and that they may find the journey ‘a little rough’. Tarpaulins were used to cover the majority of the men as they squeezed themselves into the carriages, lying on bags of shingle that were being used to represent the mail bags the planed on carrying in the near future.

“the sensation at starting, and still more so on arriving, was not agreeable. For about a quarter of a minute in each case there was a pressure upon the ears suggestive of a diving bell experience… and a cold draught of wind upon the eyes… the air within the tube was by no means foul or disagreeable; here and there a strong flavour of rust was encountered”


The rust was a result of water ingress when the tubes were laid. Upon reaching the Euston station, the ‘excursionists’ inspected the smaller tube and returned to Holborn in the same manner.

The Pneumatic Despatch Company’s station at Holborn became a popular place for an inquisitive public to visit to observe proceedings. If they were important enough, or perhaps paid for the privilege, some would make the journey themselves through the tube. Clutching a tallow candle to their chest, occasionally extinguished by the passage of air, the more frequent passengers became familiar with the rise, fall and bends of the journey and they reported hearing the sound of horse’s hooves on the cobbles above. Prince Napoleon and his Secretary were amongst the passengers carried.

Much to their annoyance the Post Office was required under Act of Parliament to provide an area of the basement of the St. Martin’s-le-Grand office for the company to build a terminus there despite there being no actual commitment to use the pneumatic service to transport mail. The underground termini when built measured 59’ by 19’ (18m x 5.8m) with an 8’ 6’’ (2.6m) ceiling. Constructed at the southern end of the GPO East building, rent was fixed at £350 per annum.

Detail from plan of underground station at the General Post Office, St. Martin’s-le-Grand. Drawn by Latimer Clark, March 1870 © The Postal Museum (POST 30/766)

The combined route of the two railways across London eventually stretched from Eversholt Street down Seymour Street under Euston Station, along Drummond St, turning into Hampstead Road, continued the length of Tottenham Court Road, under New Oxford Street, deep beneath the viaduct at Holborn (to avoid the sewers laid there), a steep incline below Farringdon Street, the speed of the carriages carried them up to a shallower level below Newgate Street (rising from a depth of 25’ to 14’ (7.6m x 4.26m) at the east end of Newgate) and to the General Post Office in St. Martin’s-le-Grand; almost two and three-quarters of a mile (4.4km) in total. No. 245 Holborn was the central station where carriages were passed from one set of rails to another.

Map of the route of the Pneumatic Despatch Company lines. From the report of the Committee appointed by the Postmaster General to consider the question of the transmission of mails in London by Pneumatic Tubes or Underground Electric Railways, February 1911

In early 1872, W.H. Barlow, the consulting engineer for the Midland Railway Company, inspected the pneumatic tubes. He concluded that the system was not suitable for transporting light loads at high speed, being more suited to carrying heavy loads at low speed. Two trains of 12 tons (12.2 tonnes) could be bought from the General Post Office to Holborn in nine minutes; a train of 24 tons (24.39 tonnes) could take the mail forward to Euston in the same time. All it needed was for the Post Office to commit to utilising the system. Although the second tube had been completed throughout its length by 1866, experimental use for mail did not commence until 1872 and continual use not until 1 December 1873. Two tunnels had been built, one for the Up traffic, the other for Down mail. Straight parts were built of cast iron sections and the bends of brick. Trains from Euston and the General Post Office were drawn to Holborn by vacuum and were propelled in the opposite directions by pressure.

Two pneumatic tubes in tunnel beneath Holborn. Various cables, pipes and wires were routed through the tunnel over the years © BT Neg No 5705

The larger carriages used in the second railway weighed twenty-two cwt. (1.1 tonne) and were each 10′ 4″ (3.2m) in length. Goods and parcels could be carried for the public and local businesses but it was a prestigious Post Office contract that the company wanted. Mails were only released to the Pneumatic Despatch Company following increasing pressure on the Post Office from their Chairman, the Duke of Buckingham. During early experimentation mails had taken around nine minutes to travel from one end of the line to the other and were conveyed in only one direction. There were soon reports that transit times had slipped, usually taking 17 and occasionally 18-20 minutes. Mail bags were also occasionally received wet from the water seeping into the tubes. The relationship, such that it was, between the Company and the Post Office rapidly soured:

“Ever since its formation the Company has persisted in its reports and published notices, and in every possible way, in affecting an intimate connection with the Post Office and in implying that its enterprise has been undertaken expressly for the benefit of it, and almost at the specific wish of the Department. The very opposite is the fact. The Post Office has used every endeavour to keep clear of all engagement with the company: it simply promised in the early stages of the case that whenever the system was actually in successful use for the public business it would consider whether the tubes could be advantageously used for the conveyance of mails”

John Tilly, Secretary

Letter to the Postmaster General, 8 July 1874


It was found that the time taken to convey mail bags from the sorting office to the mouth of the tube, hand over to the Company men, transport them by tube, and convey them from the tube to the platform, was so great that it was almost the same as transit via horse-drawn mail cart.

Conveying bags free of charge, in 1874 the Pneumatic Despatch Company tried to force the issue. They stated that nearly £200,000 had been expended on the system, their protestations continued- unless the Post Office transferred enough volume of mail to the tube to make the tube remunerative, they would be forced to cease operations. The Post Office refused and conveyance of mail stopped on 31 October 1874. Mails were simply switched to mail carts and messengers. Both the railway companies and the large road parcel carriers had also declined to adopt the pneumatic system being provided and the Pneumatic Despatch Company quietly closed its doors.

Location of the Pneumatic Despatch Company station at the General Post Office, St. Martin’s-le-Grand. Drawn by T.A.Dash, Office of Works © The Postal Museum (POST 30/766)

The rent due by the Company for their use of the premises at St. Martin’s-le-Grand fell due. From an initial £612-10s, arrears quickly rose to £1225. A winding up order for the Company was issued in 1875 however there were some difficulties in actually identifying the named company and individuals responsible for the accumulated debt. On 26 May 1876 the Secretary of the Pneumatic Despatch Company handed over the keys to the office, requesting that the Post Office forego the rent arrears. Reluctantly accepting the situation, the Post Office knocked down the building to provide additional room for mail vans and carts. They used the underground chamber for storing wood and coal. An inventory was carried out of the Pneumatic Despatch Company premises in June 1876. This made a very short list and all items were sold by auction.

Receipt for rent paid by the Pneumatic Despatch Company for use of their premises at the General Post Office, St. Martin’s-le-Grand, London. 4 October 1872 © The Postal Museum (POST 30/766)

When the Post Office used the pneumatic tubes from 1863 to 1866 and from 1872 to 1874, it was primarily letters that were transported. The Post Office didn’t actually commence a Parcels Post in the UK until 1883, however the pneumatic underground system had become known as the ‘Parcels Tube’. It is this title that was invariably used in the following years whenever references were made to both of the pneumatic railways.

More Pneumatic Proposals

The failure of the Pneumatic Despatch Company did little to dissuade others as to the merits of the pneumatic tube system and in 1876 a Mr H Temple Humphreys, County Engineer for Galway suggested the construction of a submarine tunnel for the transmission of mail between England and France. His proposal involved the use of shuttle shaped carriers fitted with electro-magnetic wheels running on two rails lying in the bottom of a line of pipes. He received a reply from the office of the Postmaster General informing him that in light of the recent experiments with the pneumatic system, the Post Office was disinclined to ‘entertain any further experiments in that direction’. This did little to put off Humphreys who made further proposals in 1887.

A rather wonderful system of rectangular tubes, 2’ 6″ by 2’ (76cm x 61cm), and running beneath pillar boxes was suggested by a Mr Duggen. These would incorporate an endless chain of galvanised iron tram wagons. It was envisaged that letters posted into the boxes would fall into the trams. His idea was also turned down.

Possibly the most practical suggestion was that put forward in 1895 by a W. Pugh, a clerk in the office of the Post Office Controller, who suggested that the London Offices be connected by 2’ (61cm) square rectangular tubes through which short trains drawn by electric motors could convey mails. He was informed that his proposal was not feasible.

Suggestion for an electrified Post Office railway put forward by W. Pugh in 1895

The same year, the engineer George Threlfell made an inspection of much of the second tube railway however he couldn’t view the portion lying in the dip below Holborn Viaduct which was found to be full of water. Threlfell proposed electric traction by means of a copper strip laid in a trough between the tracks. Current would be picked up by roller contact supplying an electric motor drawing seven railcars. He estimated speeds of up to 40mph (64kph) with loads of seven tons (6.4 tonnes) of mail.

It was concluded that the tube would require a large expenditure to put it in order for propulsion of railcars by electricity. Memories of their recent use of the tube still rankled with the Post Office and the proposal was not realised. Also in 1895, the Batcheller Pneumatic Tube Company offered to connect the London District Offices by pneumatic tube and claimed to have purchased all of the interests of the defunct Pneumatic Despatch Company. They inspected the old parcel tubes in 1899-1900. The president of the company reported that not only was there a break in the tunnel between the main Post Office and the Holborn office caused by the City’s main sewer cutting through it, but there was also an unfinished section further on. As usual, proposals came to nothing.

The story of the Pneumatic Despatch Railway does not end there however. Having lain dormant for years, the abandoned tube came to the public’s attention in spectacular fashion- the Holborn Explosion. My next blog shall look at these tragic events.

– Julian Stray, Senior Curator

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