This line was a new section of main being put into service, after it's pigged a couple times and it appears pretty clean it gets a 24 hour air test than tied into the existing system and gassed. even though their new epoxy coated steel pipes there not straight from the mill. they have rust in them, they also get all sorts of crap in them, dirt, rocks, sticks, animals, you name it. all that stuff can build up and clog valves, taps and regulators.
The ones Ken refers to are usually high tech having electronics, sensors and recorders. on in service transmission lines there used to detect corrosion, pipe wall thickness, dents and other possible defects.
Blowing pigs thru new lines is the only fun part involved.