I suppose as a last resort it could be delisted or handed over to a preservation trust of some kind.
What I've been told about News Street is that staff are afraid to even drill a hole in the wall to put up a shelf etc because of the amount of asbestos in the building.
For it's long term future it would have to find a new use post 2017, even if as a signalling museum of some kind, otherwise it will just have the bare minimum of maintenance work carried out on it by NR.
Maintaining something like the preserved Exeter West is relatively easy compared to New Street with its six floors and lift etc. If nothing else I hope the top floor operating room is preserved, although I imagine the gold fish will not form part of the listing!
As this article in today's Daily Mail illustrates, listing guarantees little: http://www.dailymail.co.uk/news/article ... tures.html
The box celebrates its 50th anniversary next year and it's interesting to see that much of the old layout (ground frames and sidings etc) can still be made out even though they have had vinyl put over them or, in the case of Stechford, something that looks like Tipex put over them to blank them out!