Have written software for a pig tracking company for the past few years. I'm always surprised at the amalgamation of low and high tech. On the one hand, some pigs can detect leaks in the line and map the pipe's dimensions. On the other hand, the industry often takes speed measurements via listening for a pig to pass a weld joint (which you can hear from far away) with a stopwatch.

The pig does often get stuck, so much so that there's a "Pig Stopped" button which influences ETAs. Every blue moon a pig really gets stuck for days or breaks in the pipe. Techs might have to use estimated locations and dig in someone's back yard.

Years into our contract, my girl friend was reporting on something farming related and said "hey can I pick your brain on raising pigs, I know you've been working with those farmers". Different type of pig tracking