Agree on the adverse abandonment - though it's relatively rare. The issues in the lawsuits seem to be related to abandoning & removing the track, then trying to do a trail. STB seems to support this. Most railroads, however, do not own their r/w - they have an easement. When they abandon the line the easement goes away. That's what happened with P&SR south of Sebastopol - some people wanted to make it a trail but the county was informed very clearly that the landowners wanted it back (though it took a while to figure out the chain of title in some cases). If the county wanted it they could buy it, for a suitable price. So the line went away though in Google Maps satellite view and even in a few spots on the ground you can still see it. Apparently STB and friends are being told much the same thing in court.

Leads me to wonder if the trails people along the Placerville Branch above Folsom have thought it out fully. They're pushing politically and in the media to replace most of the tracks with a trail. How much of the line is fee title and how much is easement? I suspect mostly the latter - since that's the way it was usually done until very recently - in which case they might have some trouble making the trail work (how much is the county willing to pay?) but the excursion rail/speeder folk (since the tracks were never removed at least below Shingle Springs) might have an easier time of it.