Originally Posted by Pooka

And as far as the corrosive oil eating up the line.....

The line is protected in a number of ways. On the outside it is coated and made waterproof. On the inside it is treated with a chemical injected into the pipeline that is an anti-corrosive, and the inside is cleaned out about once a month by running a scraper through it with brushes to clean the inside. These are known as 'Pigs' due to the 'oinking' sound they make as they scoot down the line. Yup, you can hear and sometimes feel them go by.

About every two years a 'Smart Pig' is run through the line that picks up on eat up spots inside the line. When a bad spot is discovered the line is shut down at the moment of discovery. There is no lee-way on this. It is shut down within seconds of the data being read if there is a bad spot. To ignore this is a Criminal offense.

And then it is dug up, repaired, and tested before it can be restarted.

The line will wear out, usually in about sixty years, and need to be replaced.