Mixed bag from election results. The 2014 referendum on indexing the gas tax lost, but the "Millionaire's Tax" won, with both intended to fund the MBTA.
It's not a question of whether the path works next to the train - I'm sure it does. It's that the Greenway is a quiet gravel path through the (relatively recent, not very pretty) woods, and I think that if you took NUF residents to the new GLX Community Path and said you'd do something like that, they'd reject it flat-out. The Community Path is narrow and seems designed for speeding bikes with its double yellow line.
The nicer rail trails in the system - the Community Path through Davis and the Minuteman - don't share ROW with surface rail.