Capsule Pipelines – Teens

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Pipelines are long lengths of tube. Liquids (such as water) or gases (such as air) move along the tubes, transporting the liquid or air from one end to the other.

Pipelines can be found in most places. When you turn on a cold water tap you allow water to flow through many miles of pipeline which link you to the place your water comes from. Oil and gas are sometimes transported hundreds of miles by pipeline, for example, from oil wells to ports or oil refineries.


Half of all freight in large cities is moved by pipeline. For example, 210 tonnes of water is transported by pipeline to each person living in New York, every year. If there are 18 million people living in New York, and a large road tanker can carry 35 tonnes, how many road tanker journeys would be needed each year to replace the pipelines?

Think about it…

There are probably lots of different pipes near to you now. Most are hidden below ground or hidden behind walls. What are these pipes transporting?

What would happen if there were no pipelines? What new journeys would you have to make?

Pipelines were probably not in your list of three types of transport. Why not? Do you think it is because you can not see or hear them like you can a car or a train? Do you think it is because people do not complain about them causing delays or being unreliable?

Capsule Pipelines

Image: A capsule pipeline as a transport system.
The diagram shows a capsule pipeline as a simple transport system. The pipe runs between two terminals: one loads the cargo, the other unloads it. A capsule runs along the pipe between the terminals. The capsule contains the cargo that is being moved.

Normal pipelines can not transport solid goods; they can not transport people. Some solid goods can be mixed with a liquid or a gas and transported along a pipeline. This is normally called slurrying. Solid goods like grain or china clay can be slurried. Most solid goods can not be transported in this way.

The alternative is to put goods (or people) into a sealed container, a capsule. The capsule is then transported along the pipeline. When the capsule reaches the destination, the goods are removed from the capsule.

Capsule pipelines are used like a railway. You get into the railway carriage at a station. The carriage moves along the railway track till it reaches the next station, where you get out.

How is the capsule actually made to move along the pipeline? One of three different technologies are used.

The most common technology is the use of air, called pneumatics. The capsule has the same diameter (width) as the pipeline, so not much air can get past it. Air is pumped into the pipeline behind the capsule. Sometimes air is pumped out of the pipeline in front of the capsule. The force of the air behind the capsule is greater than the force of air in front of the capsule. The capsule moves forward.

Water can be used to push capsules along, instead of air.

The newest technology uses complicated sets electric cable, which act like sets of magnets. These magnets constantly pull the capsule forward along the pipe. These work like ‘mag-lev’ trains.

Think about it…

Why can most solid goods be not put straight into a pipeline? Why do they need to be placed inside a capsule?

Capsules that carry heavy goods sometimes have wheels. Why?

What would happen if you put several capsules in the same pipeline? How much more air would you need to pump in to get several capsules to move at the same speed as one capsule? Can you think of a better way to solve this problem?


Image: A modern pneumatic transfer system in operation.
You are most likely to see capsule pipelines in shops or banks. If you look closely you might spot this: the capsule being dropped into the pipeline. What would happen if there was no capsule pipeline here? (picture source: D.D. Lamson)

Capsule pipelines could be used to transport almost anything. They are actually used to transport very little.

The most common use is to transport small items short distances within buildings, or between two buildings that are close together. Some of the capsules used are as small as your hand, most are a little larger. They are made of plastic and have screw tops to allow the items they are transporting to be put inside. The capsule is feed into a pipeline. Air is used to move the capsule along the pipeline to another location, somewhere in the same building. Capsules travel at about 5 metres per second.

Hospitals use these to move medical samples from the wards, where the patient gives the sample, to test laboratories, where the sample is tested. Banks, supermarkets and other shops use these to move cash (coins and banknotes) from check-outs to safe storerooms. Some offices and factories use them to transport paper documents.

If these systems did not exist the items would have to be transported by hand. The journey would take longer, it would be less safe, and would take more time for the staff. Like all pipelines, capsule pipelines are normally well hidden, but keep looking, and eventually you will find one.

Much larger capsule pipelines are used to move rock or stone from mines to rock crushing machines. The pipelines are more than one metre wide, with several sets of capsules being moved at once. The capsules are made of metal, with rubber tyres which allow the capsule to travel to move more easily within the pipeline. The longest capsule pipeline is in Georgia (in the former U.S.S.R.), which is 49 kilometres long. Capsules take about an hour to travel from one end to the other. There are only a few large capsule pipelines currently in use in the world.

Think about it…

What do you think are the advantages and disadvantages of using capsule pipelines to move items around buildings? What are the alternatives?

If capsule pipelines can be used to transport almost anything, why are they only used for certain journeys and goods? Do the different journeys and goods they are used for have anything in common with one another?


Image: Pneumatic Despatch Company's prototype system.
The picture shows the London Pneumatic Despatch Company’s prototype. The capsule (left) is being loaded before being pushed into the pipeline (right). Between 1860 and 1874 the company started building a network of pipelines to transport freight across London. It started before any of the London Underground railway lines were built. Unfortunately the system was so slow and expensive the Post Office preferred to continue using carts. The pipeline was often flooded by the River Fleet, which caused the freight to arrive at its destination wet. The materials and technology used were not good enough. (picture source: Beach)

Pneumatic (air powered) capsule pipelines were invented by George Medhurst in 1810. He originally thought they would be used to transport people who would travel in capsules as large as railway carriages. He decided that people would not like travelling inside pipes and invented ‘atmospheric’ railways instead.

At the start of the 1800s the only way to send a message over a long distance was by posting a letter. Around 1850 the telegraph was introduced. This allowed messages to be sent over electric wires. In London, England, all messages from other towns and countries came to a central office, where they were written down.

Mr Latimer Clark built a capsule pipeline to transport cards (with the messages written on them) from the central office to the London Stock Exchange. Many of the messages were bound for the Stock Exchange. Messages were placed in small felt bags and transported through pipelines that were only 1 1/2 or 2 inches (about 5 cm) wide.

Over the next 100 years the pipeline networks were expanded. Pipelines linked local offices within large cities. Most large cities in Europe and Eastern America had these ‘telegram conveyors’, as the Victorians called them. They were well used until new ways of sending messages over telephone wires became available in the 1960s.

During the 1900s the capsule pipelines started to appear in large department stores in towns an cities, for moving money around.

The Victorians also built capsule pipelines for transporting passengers and freight within cities. These were not successful. Only one company (see right) built more than one route. Experimental passenger capsule pipelines were abandoned, and underground railways were built instead.

In the 1960s, 1970s and 1980s the technology used in pneumatic capsule pipelines was improved by people working in the U.S.S.R., Romanian, North America, Japan and England. New capsule pipelines were built to transport rocks and other minerals. These capsule pipelines work well, but they have only replaced other types of transport in a few places.

Think about it…

Victorian telegram conveyors were very important for transporting messages for over 100 years. Why do you think they have been forgotten? Did the people reading the telegram messages know how they had been transported? Did they need to know?

Larger Victorian capsule pipelines for transporting freight were unsuccessful because of the poor technology they were using. Do you think that if the Victorians had the technology we now have, they might have built more capsule pipelines? Could they have replaced trains, cars and lorries?

The Future

Image: Tubexpress.
The picture shows a proposed capsule pipeline for moving goods between cities. The most likely capsule pipelines to be built in the future will be for transporting goods. Why? Maybe it is easier to plan the transport of goods than plan the transport of people. (Picture source: Tubexpress)

Capsule pipelines have advantages over other types of transport. Here are seven advantages:

  1. They can make better use of energy than most other types of transport.
  2. They can use any type of energy source – they are not reliant on petrol or diesel to power their engines.
  3. They do not pollute the air they travel through.
  4. Pipelines can be built underground, which keeps the space above the ground for people and means people do not have to see or hear them.
  5. They can be very fast, maybe even faster than the fastest aeroplane – less time would be spent travelling.
  6. They can be controlled by computer, without the need for people to drive them – people can do other things instead.
  7. They are likely to be safer to use than roads.

So why are we not using them now? They cost a lot of money to build. A very large number would be needed to replace other types of transport.

Most people like the idea of capsule pipelines. Nobody can explain why. They sometimes appear in science fiction.

Some people believe they have a future. Some people believe they are just a ‘pipe dream’, an unattainable or fanciful hope or scheme.

Think about it…

Do capsule pipelines have a future, or are they a ‘pipe dream’?

Are there any disadvantages to using capsule pipelines instead of other types of transport?

Think of all the journeys you make. If all the journeys were made by capsule pipeline, how many pipelines would need to be built? Where would they go to, and how long would they be?

Find out more

If you want to find out more please browse this website. For other places to look on the internet browse the library.

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