I guess this thread just comes down to what your priority for rail investment ought to be:
- Trying some sort of "SimCity" programme to regenerate the poorest areas/ regions
- Trying to colour in as much of the map as possible so that as many people are within a few miles of a train station as possible
- Trying to recreate as many old lines as possible
- Trying to take as many cars off the road as possible
- Trying to provide a diversionary alternative to existing routes
- Trying to run the most efficient railway by a certain metric (maybe the most passengers per mile compared to overall subsidy required)
Some improvements can tick more than one box - e.g. the Borders line rebuilt an old line whilst also bringing thousands of people within a few miles of a railway - but we could make a lot of other improvements for the sake of the £400m spent on the Borders line and it's worth considering the opportunity cost.
Looking at the "Waverley Line" figures, you've got around 1,200 departing passengers per day spread between the three Borders stations. Spread those over the daily departures and you're talking thirtysomething passengers per train (assuming that everyone from Tweedbank, Gala and Stow are travelling into Midlothian/ Edinburgh). Some services will be busier than others, sure, but still... thirtysomething passengers on each service into and out of the Borders... it's not huge, is it?
Some people will consider that the price is worth it (though I suspect that the same people would think that the price was worth it regardless), some people would put "reconnecting small towns" and "putting more people within a shorter distance of a train station" as goals in themselves, but for £400m we could have got a lot more cars off the road and put a lot more people on public transport elsewhere in the country.
For example, the Edinburgh Trams cost about twice the cost of the Borders line (both went over-budget and took longer than expected so please spare me the "we shouldn't invest in trams because such projects are over-budget...) but carry over five million passengers a year (in comparison, the three Borders station have under a million passengers a year). And the trams seem to be growing and growing whilst the railway figures look closer to plateauing. Now, I'm not claiming the Edinburgh Trams as a perfect example of how a project should be managed but it's worth comparing two schemes in the same corner of the UK.
Looking at these figures, I'd be tempted to argue that extending the tram to Leith would be more efficient than trying worrying about Hawick/ Carlisle - the population of Leith is maybe half that of the entire Borders region but with much greater population density so much easier to serve with public transport (funny how we get excited about giving ten thousand people in rural towns a train station within a few miles of their houses but ignore areas of large population like Leith that aren't so quaint and rural...).
But, I'm trying to be rational and compare numbers - some people see reinstating an old line as an end in itself - some people put unquantifiable value/benefits on colouring in bits of the map - it just makes it impossible;e to have a rational argument with them when they've got their minds made up already.