Nationalisation was like much in the late 40'ies and 50'ies a consequence of coming out of 7 years of fully mobilised war footing. Yes with some ideology thrown in (but did Churchill privatise them, no, so lets not get to bogged down in that).
However, way back in the day, the original robber barons ran a pretty tight ship. So suggesting the nationalisation was a intentional and economically founded decision to intervene in a market that was prone to failure. Is not borne out by the evidence.
The real issue, as I've been saying is that we really have improved on the infrastructure since the last generation of robber barons.
Considering the importance of an efficient and affordable railway network a a island that's now heavily urbanised and probably cannot afford any more motorways, or that many cars for that matter. Getting bogged down with partisan ideological nonsense, is hardly productive at a time when we need to be.
So shall we stop aruging past each other as to the 'justest' system of the railways and start looking to the most efficient system.