Llanigraham
On Moderation
If the point of this is to restore a link between North and South Wales that wouldn't require going through England, looking at old maps shows a second link going through Radnorshire, connecting into what is now the Heart of Wales Line near Builth Wells. I assume the geography there is even worse, though?
That is the old Cambrian Railways line. Again the majority of it was single track with severe inclines and curves. Very little is now extant and what does remain has been built over in many areas, plus it passes through even less populated areas.
At the southern end it would need an extension to Abergavenny to join the Newport - Hereford line, and would need a reversal at Moat Lane Junction where it joins the current Cambrian line.
