As you say Bow Street is a useful stop but I think the case for re-opening Carno is even stronger. It really is ridiculous that there are no stations at all between Caersws and Machynlleth making life very difficult for those who can't or don't drive. Numbers at Carno would never be huge given how sparsley populated the area is but the lack of stations along the Cambrian mainline compared to the Cambrian Coast is very striking.
I agree, in that I think Carno (done correctly) could be a very valuable stop on the Cambrian.
It definitely needs good, free, parking to be valuable so that even those who do drive can see it as a good place to catch the train. The parking situation at Caersws (and even Newtown and Welshpool) isn’t great really and I wouldn’t be surprised if some are out off by it.
But living in the area and driving through Caersws to get to Mach for work each day, if you can’t or don’t drive, life is difficult due to being in rural wales and having a station at Carno wouldn’t make a huge difference unless you live near.
One of the biggest issues with reopening Carno is timings.
Adding Bow street removed a few minutes off the Turnaround time at Aberystwyth and Carno would take even more.
In the down direction the line speed at Carno is 120Kph (approx 75mph) and then picks up to 130KPH (80mph) towards tallerdig.
Compared to Bowstreet where line speed is 90Kph (55mph).
Fortunately there are some fancy new trains with much better acceleration and braking due next year that will almost certainly reduce the section times as well as being a lot faster to boot up the onboard ERTMS when turning around at Aberystwyth which would make Carno much more viable from a timings perspective in my opinion.
Then there is the debate around whether or not you make it a single platform like bow street, or do you make it a loop. A loop could be single platform like Dovey junction or 2 platforms like Newtown.
Making it 2 platforms like Newtown and scheduling trains to cross there instead of Tallerddig would be best in my opinion, always better to be stuck in a platform than in the middle of nowhere in my opinion.
But it certainly could provide much needed, additional year round revenue for the Cambrian.