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.
Example
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?