What we all want is more services, yet the existing network is full so therefore you have to expand it to allow for things to take alternative routes even if the ultimate destination is the same.
It is all very well singing the praises of "High Speed" rail, but that costs even more than a normal line to design, build and run as it requires far more detailed operation including in cab signalling, which conventional lines don't, then there's the extra cost of rolling stock to go with it too.
There are plenty of old routes down here which could be used to take traffic off of the roads, including some relatively simple ones, such as redoubling the line from Castle Cary to Yeovil and Weymouth, it is strangled by the single line sections, a chord to/from the Castle Cary line to the Waterloo line (Bradford Abbas side & there used to be one!) and from the Waterloo line to Weymouth line would make journeys from Wiltshire/Devon to Dorset Coast a cinch. The A37 is a nightmare journey from Bristol to Weymouth, a journey that is going to be quite popular in the next 18 months, as will a journeys from the other parts of the West.
Another couple of lines that would be useful is are the ones from Kenilworth to Berkswell, ideal for diverting freight or passenger services away from Coventry & Rugby to Leamington Spa, yes it would need to be realigned at the Leamington end due to redevelopment, but again ideal for diverting freight or passenger services and freeing up capacity, recent events on both the East & West Coast mainlines would have shown how useful the Waverley line would have been.
It is only when you start looking a bit more carefully at putting some of the smaller lines back in do you get the "bigger picture" and find that you can actually increase capacity exponentially.
The railway is not all about making money, it never will make a profit, it will always require some kind of subsidy and all the time things like the RHA exist a select few government minions and their paymasters will always see to that, it's about opening the country up again, keeping car usage to a minimum and being kinder to the environment, especially with petrol & diesel costs going through the roof!
We are now finding out what Dr Beeching and his cronies inflicted on the country was absolute folly and it is time to not only to rebuild the smaller (call them feeder or cross country branches if you like) but enhance the GWML, MML, West Coast, East Coast & East Anglia mainlines too.