Thinking of Rolling stock - Anglia will be releasing tranches of 153's and 156's - which could potentially allow a cascade to / within Wales to good effect.
Not sure about 153s, since Northern, Anglia and Great Western have all decided they would rather see the back of them than make them compliant with TSI-PRM regulations. ScotRail might be releasing 5x class 156 in December 2018 though, added to the 9 units from Anglia in late 2019 that's 14 units. 9 could cover a half-hourly Swansea-Whitland service with a new passing loop needed between Kilgetty and Narberth and one every two hours extended to each of Fishguard, Milford and Pembroke Dock. That would release a 175 or two from the Manchesters west of Swansea, and the three 150s on the SWA-PMD service. Essentially, the 14 156s might just be enough to allow the 8 153s to go for scrap, but EMT are likely to need these 14 units to replace their 153 fleet, unless they use 170s to do that (I wonder what LM are going to do about their Sprinters).
If anyone does decide to turn the 153s back into 155s and make them compliant with the TSI-PRM regulations, how long would such a project take?
I don't think it would be feasible to reinstate the old direct link from the Neath Valley into Neath GWR station but instead I suggest a new single track route
Interesting suggestion, but I don't see the need since the way I look at it the Vale Of Neath line is a 'Swansea ValleyLine', running into a 'Swansea Docks' station near the Fabian Way Park & Ride site. Of course you will need a tram from there into the city centre, unfortunately I cannot see a way of extending heavy rail into Swansea propper.
yes, understood. But that does not solve the issue of what i've termed the 'Class B' stations. Would your semi-fast trains attract enough passengers without serving the likes of Bucknell and Knucklas?
You're right, it doesn't do anything for the Class B stations. I think I did consider a every-two-hours stopping service from Shrewsbury to Knighton/Knucklas, with fast through trains to Swansea in some of the other hours, but for some reason discounted it. Maybe it didn't work with the positions of passing loops.
I'd be happy to be proved wrong (really), but I'd wager the returns on beefing up Llandovery-Llandeilo-Ammanford-Swansea services (especially the last two) would be far more immediate and sustainable than struggling to implement a comprehensive through service upgrade as per your TT.
You are absolutely going to get more revenue from regular commuters than occassional leisure traffic, so you are probably correct that Ammanford-Swansea services would be a bigger win in terms of revenue, but in terms of giving the entire line a chance of being seen as a useful asset I really think a number of through (semi-)fast services are absolutely necessary. My general feeling is that railways are better at providing long-distance fast links than they are at rural all-halts services (like the HOWL currently is). Buses don't need stations and aren't slowed quite as much by having to stop, so can stop everywhere more effectively than trains.
There's also the fact that going via Swansea and Cardiff is a heck of a long way round if heading to Scotland or the north of England, and there seems to be something about linking Manchester with Milford Haven. The old Manchester and Milford railway company failed of course, yet years later Milford Haven has through services to/from Manchester every two hours via a crazy indirect route! My music teacher has also asked me if there's a sensible way of getting to Manchester from S.W. Wales and I've said the only remotely logical route would be the HOWL, but of course there's a missing link between Carmarthen and Llandeilo which would be very hard to justify. If a bus service from Carmarthen connected into my proposed fast services at Llandeilo the journey to Shrewsbury could be done in under 3 and a half hours, only 15mins faster than some of the current through services I'll admit but it shows that there may be some potential in long-distance links via the HOWL.
I think stub services are the best option for the HOWL, especially because Sugar Loaf and Cynghordy stations are dead and there probably isn't a demand for more services between Llandrindod and Llandovery, compared to northbound and southbound respectively.
I think there could be demand for both, there may be more demand on the stub services yes but I prioritise the faster through service for some reason. That might be because, looking at Google Maps, Ammanford to Swansea currently takes 32min by car and 52min by train. That might not be a problem in the peaks, when road congestion could give rail the upper hand, but doesn't look like a recipe for strong off-peak use.
In terms of Llangennech and Bynea, the railway will probably never be able to compete with the bus service. I think you'd need a Swansea type metro service stopping here to get passengers to change their journey habits, though you could have trains scheduled to stop here on the SDL.
That's another part of the puzzle which is my lack of enthusasim for a 'stub service' at the southern end of the HOWL. Giving Llangennech and Bynea an enhanced service would make it harder to withdraw close those two stations, allowing the HOWL to do something about that journey time disadvantage into Swansea. Trains would take the SDL's viaduct over the Loughor then head south to Gowerton over a new line serving the eastern edge of Gorseinon, leaving nothing to serve Llangennech and Bynea unless you brought a tram-train up the cycle track from Killay to Gowerton then over the new viaduct to Llanelli. Being a tram, perhaps it could run to the centre of Llangennech via Llanelli bus station and Parc-Y-Scarlets rather than using the current out-of-town station. That last bit is probably pie-in-the-sky, but I just like throwing it out there.
I am sure you are right on the timings of any pilot fast Carmarthen -Newport service - I think I was influenced by my memories of a 'peak' relief service from the mid-70s. AFAIR we had a 14.50-ish ex Swansea to Newport, Cl 47 non-ETH with Mk 1 stock, which returned from Newport at around 17.00, arr Swansea 18.20 or so. 