Yes, of course the A55 improvement have contributed to this. In exactly the same way a new railway will attract new usage. Rail useage is growing hand over fist at present and now is the time to capitalise on that. It will also offer an alternative route to mid wales (albeit a long way round) when that bridge near Newtown collapses or floods again as it did in the mid 90s when I was at uni in Aberystwyth!
I agree that a reinstated line would attract new usage, but I don't think it will be anywhere near a level required to justify the huge expense that would be involved.
This is not comparable tot he Borders reopening in Scotland. Carmarthen isn't Edinburgh!
It's clearly never going to make a return on the capital investment of reinstatement, but I suppose the question is could it cover it's operating costs? With ETCS and minimal station staff, the operating costs could be held down, I suppose.
And since CPOs would be required to get the trackbed back, you could always buy the trackbed to Newcastle Emlyn and offer that to Gwili as compensation!
Dealing with the Gwili isn't the greatest problem! The biggest problem is that since hardly any line in wales covers its operating costs, there is now ay that any government of nay political hue is going to sanction this at the moment or in the short or medium term.
There is no way on earth that the reopened line will cover its costs, so quite apart from funding the track relaying, purchase of land and construction of stations, the government would be basically committing itself to increasing the money required to run the railway every year on top of that.
A friend of mine who works for the police in a specialised role and is based in Cardiff has to attend meetings in Bangor. He had been using an airline flight that went from Cardiff to RAF Valley on Anglesey, and said the main other users of this flight were Welsh Assembly people who I suspect have duties in either Caernarfon or Bangor.
Point is, I deduce from this activity that the main road up the coast to Aber maybe isn't too good, and as others have mentioned it is a long way round to go via the Welsh Marches line and down the North wales coast.
But whether a reinstated line would generate traffic en-route is a different matter. Otherwise, South Wales to Caernarfon and Bangor is presumably a "time" issue.
The point is that anyone driving from Cardiff to Bangor wouldn't go via Aberystwyth in any case.
Time wise, a traveller from Cardiff would have to go to Carmarthen ( say 2 hours) then up the reopened line to Aber (say 1.5 hours, then on to Machynlleth to connect with the Cambrian Coast line (say another 0.5 hours, then up to somewhere unspecified (maybe Afon Wen and another expensive reopened line to Caernarfon and Bangor (another 2 hours?) so at 6 hours to Bangor the route wouldn't even be that competitive time wise with going via Shrewsbury!
There's simply no justification for this reopening in the way these things are currently looked at. Other projects will have greater benefits and lesser costs attached to them. That's just the way it is, sorry.