Line reopening would be an enormous boost to Wales
Source: Patrick Adams
My understanding is that a new more direct route will be used between Carmarthen and Pencader. A new route into Aberystwyth itself will also be needed.
The original Victorian line was designed for slow steam traction, where gradients were more of an obstacle than curves. Modern trains and construction methods should enable a modern railway with faster journeys. This should be an enormous boost to the economy of that part of Wales, if it ever happens.
Re: Route study confirmed for Carmarthen to Aberystwyth re-opening