The above mentioned trackwork project is still in effect, on Mondays through Thursdays until a time later this month. According to the releases, the CAROLINIAN is supposed to operate one hour behind schedule.
The fact that it has been observed running three to five hours behind, despite its only running within North Carolina (Rocky Mount-Charlotte) indicates that there is more at play here. CSX, for one thing, has had heat-related speed restrictions all week in much of its service area. If the PALMETTO (which carries CAROLINIAN passengers from Northeast Corridor points to Richmond) is being delayed south of Washington, then that is delaying the departure from RVR of the substitute bus (which has no heat restrictions on I-95), and that in turn is delaying the RMT departure of the CAROLINIAN even more than intended.