Have you tried ogauge forums O Gauge Railroading On Line Forum: Forums ? I do most of my buying and swapping on there. I've got a few different Pennsy passenger sets i was thinking of selling if your interested.
Not sure of the track O or what it is, but I do have some old Lionel stuff from the 50's laying around somewhere, including like 100 pieces of track. Is that what you are looking for?