I used to think opening a station at St Clears would be a good idea, now I'm not so sure.
The area's railways look to be in a tight spot to me. Cardiff generally seems to be a more important destonation than Swansea now, yet it is the line to Swansea they are improving (Gowerton redoubling, which in itself is great news) with no indication on whether the line to Cardiff (the Swansea district line) will retain it's full capability so services can be introduced in future. Any loss of the potential of the Swansea district line would just be part of a tripple-whammy (maybe even quadrupal), hitting the competitiveness of rail in the area very hard.
As SWWITCH says here:
http://www.assemblywales.org/calendar-document-content?id=58373 "A comparison of journey times between rail and road shows that rail continues to be competitive on the main east-west rail route from Swansea to Haverfordwest. It is likely that the rail route between St Clears and Haverfordwest will become increasingly less competitive when the recently announced improvements to the A40 trunk road at Llanddewi Velfrey and Robeston Wathen are completed".
The A40 Llanddewi Velfrey works would make the double-whammy, the tripple-whammy being diversion of the main road to Pembroke and Tenby between St. Clears - Red Roses onto a faster alignment. And quadrupal? Loss of the Intercity services due to
IEP▸ not being able to fit through Narberth tunnel.
I don't know about the Pembroke branch (it might not be competitive anyway, but the new road certainly won't help either way) but I think there are two options to keep rail time competitive on the Milford - Swansea route.
1. Restrict Clunderwen and Clarbeston Road to a 2-hourly stopping service from Milford Haven to Swansea alongside 2-hourly services to both Milford and Fishguard which don^t call at Clunderwen and Clarbeston Road. This would give an hourly service non-stop from Whitland to Haverfordwest / Fishguard & Goodwick, allowing for trains to reach 90mph between Whitland and Clarbeston road (with a linespeed upgrade required of course).
2. Don^t build the A40 bypass, which saves the cost of upgrading the railway to 90mph and the cost of the bypass. Much the better option in my opinion, since it means the money can be used to improve public transport in another way (St. Clears station perhaps, or a waiting room at Whitland).
Anyway, that was a bit off-topic but my point is we are going to have enough problems keeping the route competive without introducing extra stations. I think St. Clears has more justification for a station than Clunderwen though, why did they close the one but not the other? Both should still be open.
If you can sort the time problem (knock 10mph off the road speed limit perhaps, hint-hint) then I'd very much like to see Pembroke Dock/Milford Haven - Swansea stoppers calling at St. Clears, alongside faster trains from Milford and Fishguard to further afield that don't call.