I can’t speak for the STL end as I’ve not been there but the CHI end is pretty much all industrial. Not much population. Unless industry is the nimbies. Maybe but I kind of doubt it. It’s Metra’s Heritage Corridor and it’s the lowest ridership line.
Excluding Joliet which is also served by the Rock Island line only 100,000 people live in the towns along the line. And that’s over a 30 mile stretch again excluding Joliet.
And I suspect it’s the same on the STL end. Not much on the Illinois side of STL but industry.