This "discussion" betrays a fundamental difference in the way such matters are seen between the old world and the new. Being in the old world we generally work on the basis that, for instance, if a locomotive needs a new boiler it will get a new boiler, ditto wheels, tanks, etc. The National Railway Museum has its own rules which generally mean major replacements are a no-no. I understand this position which normally applies to anything unique.
Buildings pose a different problem - it is okay to preserve (freeze) a building in a particular time frame but if it's a workshop you'll either preserve it (i.e it is of no use for modern purposes) or you'll use it having complied with all the modern rules that apply. If the building is "listed" then generally you will be able to do little or nothing to it - the fact that you own it doesn't mean anything!
Gavin
Linslade
Bedfordshire
UK
Garratt Locomotives
[
www.beyergarrattlocos.co.uk]