Are the poles heading towards properties? Or taking the cable back to the exchange?
If the former, then they could be replacing D-side cables, or at least a segment of the cables. But it would be strange to go via the FTTC cabinet.
The latter seems even less likely. E-side cables really wouldn't go via the FTTC cabinet.
It could be that they're having to replace *everything* that were underground at that point - D-side and Tie-cable, at the least. That could explain it.
If it were fibre, then someone could have ordered FTTPoD, and this is a segment of the build. But it would be strange to involve *either* cabinet then - you'd expect just the manholes to be involved.