SEPTA owns the entire line, including a few former station sites. They still own the station site in newtown, but only one branch of the wye that was there. The rest of the wye is on private property. They also own part of the the former yard site that served the now gone agway.
Legally the line is out of service, not abandoned. If it were abandoned legally, any portions with trails etc would have to be purchased outright. That has not happened.
I still have hope for service restoration. The big issue is that it'd have to be done as one whole chunk at once, because no single station between fox chase & newtown added up would garner the needed rider numbers. That, plus you want to rebuild the track beds & replace any bridges at the same time, that way once everything is done, service can commence along the whole line on the first day.
Next stop the square, journal square station next!