Update: looks like they’re floating the idea of extending the Piedmont up the S-Line. The article @apbassett linked here includes this quote from the NCDOT Rail Director:
“We applied this year for an FRA federal-state partnership construction grant for the (17-mile) S-Line segment from Raleigh to Wake Forest, N.C. The goal is to develop serviceable sections that will allow extending Piedmont service north,” says Orthner, pointing out, “it is the most complicated segment where we have already received federally-matched grants for highway grade separation construction.”