In terms of Uckfield - Lewes, we don't know whether the route could have been made to cover its operating costs before closure. It was never singled. The stations at Isfield and Barcombe Mills were never de-staffed. Infact, the whole Hurst Green to Lewes section was considered for closure, and this was found to be too problematic and had to be reprieved North of Uckfield, so would have had to have found savings anyway.
This whole narrative that "there was no other option to closure" isn't borne out by history, as there clearly was an alternative for cases such as Hurst Green to Uckfield from an operational point of view.
As I've said, the impression I get is that the British Railways Board really was committed to creating an economically viable railway network. If the goal was just to close things, they'd have been able to get rid of a lot more. That some sections proposed for closure on economic grounds were reprieved doesn't disprove that - the economies made on those sections may very well just have reduced losses to a palatable level.
Do we
know that it couldn't be made to pay? No, of course not. But the available statistics supported a view in 1963 that it didn't pay its' way. In 2008, with operating economies compared to the pre-closure line and national rail passenger numbers about 35% higher than in 1963, it could. Anything in between is supposition. Given that passenger levels fell consistently from the early 1960s to the late 1970s, didn't really start recovering until 1993, and took until 2000 to get back to pre-Beeching levels, assuming that an operating ratio from 2008 applies to the 1970s and 1980s is decidedly optimistic.
On a very cursory assessment, even with economies I suspect that the line would have become totally uneconomic in about 1972, might just about have covered its' costs for a few years in the late 1980s, but wouldn't really have started paying its' way until 1997.
From a political point of view, the alternatives were cancelling some debt and supporting socially necessary services. These were both changes that were brought in, in the late 1960's.
They were indeed. In fact, the line you keep referencing was closed after the debts were written down and support for socially necessary services became available. The decision to close the line was taken after studies into the potential for economies. It still closed. The line was given every chance to prove that it could be worked at a reasonable cost, but never did.
True, they never actually tried working it as a single line - but they didn't need to, the costings could have been done fairly accurately and the traffic levels were known. There was no point spending money on an experiment if all the evidence suggested that the line would still prove uneconomic.
There's no question that marginal lines were a large proportion of the closures. York - Beverley was clearly marginal and that was a worked example. I've seen referance that the Swanage branch actually made money, yet it was closed to satisfy the requirement to get rid of milage.
More likely, it was closed because of faulty data, or because other factors made the Swanage line impracticable. I don't argue that all the closures were correct, only that they were made with the best interests of the railway at heart.
You don't. You lose the structure that imposes this self-destructive debt bondage in the first place.
Not an option. The railway couldn't force the government to hand it a blank cheque. The British Railways Board was required to run the railways as an economically self-sustaining operation, and that meant servicing their debts.