What does the United States Patent and Trademark Office status 604 Abandoned after inter partes decision mean for the trademark? Is the trademark in the public domain or so clouded that it could be used as such? Does the original claimant involved have more rights or explicitly zero rights to the mark than a third party?
The concrete reason I ask is the monthly transit pass I happened to buy today uses the old Pennsylvania Railroad PRR trademark as the authenticity hologram. (The transit agency, SEPTA, was a customer of the PRR and its successor, Conrail, 1962-1982, and currently leases track from another PRR successor, Amtrak, but is not itself a successor to the PRR bankruptcy) A little googling found the Justia link above, showing this status change very recently, in October 2015. I naturally wonder what this means.
Is SEPTA in the clear? Given decades of operating agreements, they may have explicit unexpired contract rights to use logos in printed schedules or fare media without owning them?
How about historical rail collectors who paint the PRR livery and logo on rail equipment?
If I, wholly unrelated, wanted to make PRR memorabilia (or hypothetically paint a PRR logo on a van then employ it as an Uber or similar to trade on the 150 year transportation history of the mark) does the abandoned trademark status permit this?