Denver Airport Luggage system. A "PRT" for luggage this MASSIVE FAILURE is well documented by many scholars as a famous engineering cock-up, like replacing the air traffic control system, and the FBI computer systems.

United Airlines dumped 186 million US dollars in debt on the public by
declaring bankruptcy and threatening to dump Denver as a hub unless the
public was to eat the debt on the luggage "PRT" system after they shut it
down as a drain on resources. It cost a million a month for the luggage
eater to run and also cost United its baggage handling reputation.

It has all the earmarks of a PRT project. guideways, autonomous pods,
on demand service, scams, techno-hubris and, of course, not working.

Proponents always say the same thing of PRT failures: "that's not REAL PRT."