“This is accomplished by inserting the pig into a ‘pig launcher’… push it along down the pipe until it reaches the receiving trap – the ‘pig catcher’… there are “smart pigs” used to measure things… though some product can be lost when the pig is extracted… All systems must allow for the receipt of pigs at the launcher… pigs must be removed, as many pigs are rented… the pig can be ejected from the barrel and operators have been severely injured when standing in front of an open pig door… the pig is shuttled up and down… Modern intelligent pigs are highly sophisticated… Some smart pigs can combine technologies… the pig is unable to directly communicate with the outside world… It is therefore necessary that the pig use internal means to record its own movement during the trip… The original pigs were made from straw wrapped in wire… There are several types of pigs for cleaning… A pig has been used as a plot device in [the] James Bond film Diamonds Are Forever, where Bond disabled a pig… A pig was also used as a plot device in the Tony Hillerman book The Sinister Pig.”

My thanks to Duncsnoai Plover for drawing to my attention this exciting stuff about modern pigs (many of which are rented).