Assuming I am looking at the same document, I'm not sure what the lines on the map are supposed to represent. For the most part, it seems to show the current service pattern (eg. Aberystwyth to Shrewsbury shown as a dashed line; assumed to mean 2-hourly service, with upgrade to hourly described in text) but Cardiff to Cheltenham is a solid line (which I guess means hourly) despite the current 2hr gaps in the timetable.
Regardless of the map, regrettably there doesn't seem to be any enhancements planned for Pembrokeshire in the new franchise beyond reinstatement of the community rail partnership. Fishguard could well be left with the gap of over 5 hours in daytime services and Haverfordwest with the current 2-hourly service that does not feature an arrival from Milford Haven in the morning peak despite the traffic jams that frequently build up (Haverfordwest seriously needs some bus lanes which given the lack of space probably means closing certain roads to private motor vehicles). Even the key interchange station, Whitland, seems likely to be left as a windswept halt with no facilities despite being over the border in Carmarthenshire.
I don't think the Pembroke & Tenby (P&T) is an easy route to timetable; I'd like to see the following services between Carmarthen and Llanelli, with most of these continuing at least as far as Whitland:
- 1tph FAST to/from Cardiff (calling only at Port Talbot and Llanelli)
- 1tph Semi-Fast to/from Swansea (calling at Gowerton, Llanelli, Pembrey & Burry Port)
- 1tph All-Stops to/from Swansea
In order for this to work with Carmarthen-Swansea at a frequency of roughly every 30 minutes there needs to be a dynamic loop between Kilgetty and Narberth and the Tenby loop is near-useless. It would still only be a 2-hourly service between Whitland and Pembroke Dock; going hourly as far as Tenby would mean the unit would sit at Tenby for ages; it could get to Pembroke Dock and back in that time, going hourly on the whole branch, except that you'd need another new loop for that to work.
The P&T has alot of stops, which don't help, and going via Tenby is quite indirect compared to the road if you're going between Pembroke and Carmarthen. The slow journey times make it probably harder to justify an hourly service, because you've lost some of the potential traffic already due to the slowness. Once you get to Carmarthen, rail is at a further geographical disadvatage at the moment since almost all the trains go via Swansea which adds 15 minutes at least. That's why I have the hourly Cardiff-Carmarthen FAST on my list above.
On the topic of the London - Pembroke Dock services; when I was at Carmarthen earlier there was quite a crowd waiting on platform 1, with the staff making manual announcements for everyone to stay behind the yellow line. The heavily delayed (35 late according to Real Time Trains) 12:47 GWR service to Pembroke Dock eventually arrived and when it was gone most of the crowd had too.