Send it Through the Tube

The pneumatic tubes at the bank are intriguing things, especially to a child. Mommy puts the check in the bottle, sticks it in the machine, whirring sound, wait, wait, whirring sound, and there is a wad of cash and some Dum-Dums. Pure magic.

But have you ever said to yourself, I have seen these things at the banks forever, when in the world did somebody come up with this?

This sort of delivery system has really been around quite a long time, and occasionally even comes up as a mass transit revolution, complete with self-advertising Wikipedia editor. The first major application of the idea came thanks to the London Pneumatic Dispatch Company in 1859 starting with an initial investment of £25,000. A test system was constructed in Battersea, in south-east London in 1861. The tube was an oblong shape of approximately 30 in x 33 in, and the 3 ton capsules were moved by pressure created by a 30 horse-power engine with 21 foot diameter fan.

The first permanent line was installed between Euston station of the London and North Western Railway, and the North West District Post Office, a distance of just 1/3 of a  mile. One cart could cover the length of the tube with 35 bags of mail in 1 minute.

In a news report of the day, one journalist described the system’s operation thusly:

“Within the modest brick shed near the bottom of Euston Square, there is the mouth of the tube, and there are the travelling trucks, ready to be thrust into it; and as we look, a bell rings at some distance up the rail – this is a signal that a mail-train has arrived at the Camden station, and that it will speedily be at Euston Square. At this signal we hear a shovel of coke thrown into a furnace, a small steam-enging begins to beat swiftly, and a whirring sound is heard within a great iron case which is noticed on the side of the shed. This, we are informed, is the pneumatic wheel – the mouth, in fact, which is to propel or draw the trucks through the tube. The wheel is twenty-one feet in diameter, and is composed of two discs of iron, not placed quite parallel to each other, but tapering off from the axis to periphery. These discs are braced together by spoke-like partitions, and these partitions communicate with an opening for the entrance of air about the axis. As this wheel rapidly revolves, the air is sucked in at its centre, and thrown off in a perfect gale at its open rim or edge. This gale is not allowed to disperse itself, however, but when any work has to be done, is confined within a paddle-box, and allowed to pass out at the will of the engineer through a pipe in connection with the great pneumatic despatch tube. In like manner, the air that is sucked in at the axle is all conducted from the despatch-tube by a similar pipe. Here, then, we have the means of pulling or pushing the travelling carriages along their subterranean road, and as we speak we see it in operation: for a mail-guard opens a door, throws in two or three mail-bags just snatched out of the guard’s van as it rolls into the [mainline] station, the iron carriages are shoved into the tube, the air-tight door at its mouth is closed, and the engineer, with a turn of a lever, directs a torrent of air upon them, and we hear them rumbling off on their subterranean journey at a rate, we are informed, of twenty miles an hour. Ere we have done looking and wondering, we notice that a water gauge, on which the eye of the engineer has been fixed, becomes depressed at one arm and elevated at another. “It has arrived” he says; and almost ere he has said it, a bell connected with an electric telegraph warns him that the attendant at the other end of the tube is about to thrust the carriage into the tube on its return journey. It has been pushed along, as we have said, by the pressure of air thrown out by the wheel, but it has to be pulled back by suction; the value of the suction-pipe, in the connection with the centre of the disc, is accordingly opened, and speedily we hear a hollow rumbling, and out shoots the carriage, ready once more for fresh bags.”

There were several other lines built in the ensuing years, but the Post Office never really saw the time/cost savings that they hoped for. In 1874 the system was shut down, although the tunnels remained for at least 20 years. At least one attempt was made to re-capitalize the company in the hope that the Post Office would bring back the pneumatic cars, but it never happened. Most of the tunnels appear to have been filled in during the late 1920s due to a gas explosion in one causing them to be noted as a safety concern. Two of the cars still exist, one in the Museum of London and the other at the British National Railway Museum at York.

Image and information sources here and here.