For example, a 32 mile old railroad in Santa Cruz, CA that is being revitalized for electric trains AND getting a bike path built alongside it: https://www.railandtrail.org/discover.html
Common sense either you need to
1. shrink the train (and what more than "light rail" speaks to the pain and embarrassment that accompanies crawling back from automobile culture)
2. expand the right-of-way
3. commit to turning over the trail once the rail is reconstructed
Which is it?
I live near a rail line that was converted to a multi use trail and as part of the conversion process there had to be a decision made about past encroachment onto the right of way — mostly homeowners who had pushed their property boundaries closer to the actual rail. Looking at the planning maps it was surprising how wide the path is, but I suspect that it is to allow for the embankments and cuttings needed to keep a railroad level (or at least to keep grades within tolerance)
The Rail Trail will be within a mile of 92 parks, 44 schools and half the county’s population. In addition to the 32 mile Rail Trail spine, the MBSST Network Master Plan includes 18 miles of spur trails connecting the Rail Trail with other destinations.