I try to be pragmatic about all the nationalisation/privatisation stuff - I'll believe in whatever works best - in the context of the billions of pounds of money sloshing around the industry each year, I'm not worried about the fact that TOCs need new uniforms for their staff every seven years or the fact that there are multiple teams of people responding to tweets (even under a centrally controlled nationalised system, you'd presumably want local teams responding to local problems/ incidents).
I guess the question for me then is what size is most efficient for a TOC? And do you measure that by revenue/ number of carriages/ number of staff?
e.g. you can have a twelve coach EMU with one member of staff on board or a single carriage 153 that requires two members of staff, so I don't know whether it'd be better to try and split the (five? ten? twenty? thirty?) TOCs based on revenue/ carriages/ staff?
I don't have a "feel" for how many TOCs there ought to be but in the interests of keeping things competitive enough to encourage firms to bid (i.e. not so huge that only two or three companies would be able to take them on, but not so insignificantly small that it's not worth going through all of the tender process) and to avoid the issues of feast/famine then maybe enough TOCs so that there's a new TOC every four to six months and each franchise lasts seven to ten years - which would mean in the region of twenty franchises? That way each TOC should be a reasonable size and you'd not have a period where no franchises were let for long periods? But I've no black/white opinion over one number being particularly better than another - I only suggestion twenty-ish to keep things fluid and balanced - anything shorter than seven years means little time for improvements and anything longer than ten years risks stagnation and no incentive to keep up the momentum of the first few years. You could get lucky with a Chiltern but also end up lumbered with a badly written franchise like the first Wales & Borders one, so a seven-to-ten years period feels about right.
If you're looking at changing some existing TOCs without any huge changes to timetables/ ordering new trains etc then I certainly agree with splitting up TPE - it's got three independent "arms", which have very little to do with each other - it'd be easy to give the WCML services to Avanti, give the Huddersfield services to Cross Country/LNER and give the oft-forgotten Hope Valley service to EMR/ Northern.
If you don't give the Huddersfield services to LNER then you could certainly give the Northern services around Newcastle/ Middlesbrough to LNER (operationally separate
In a united Britain, Wales & Borders ought to be split along the old "Wales & West'/ "Central Trains" "FNW" lines, but I appreciate that it'd be far too politically sensitive to do anything about it
Beyond that, you're talking about splitting services up to suit boundaries. e.g. any "east"/"west" split of Northern would mean questions about which side got what (go back to the RRNE/RRNW days and chop routes like Leeds - Chester?). I could see merit in splitting XC with Avanti getting the full "Manchester - Reading" corridor and the "Derby - Cheltenham" corridor to EMR, but that'd be major surgery!
But any railway is going to be split into several divisions - look at how our "National" Health Service has the same back office functions provided in many many places - it'd be impossible to run a nationalised railway without significant devolution/ "silos" - anyone is welcome to kid themselves that a twenty first century "BR" would be one big happy family but look at any major public/private bureaucracy to see how split it would all be. Also, if you're going to have compensation an "delay repay" etc then you're going to have to accept paying lots of people to calculate the losses and attribute them to a business unit - it's going to be messy whichever way you want to split things up.
(and also, often it's the people who claim that the only reason BR closed one route in the 1960s instead of a parallel one was because of some long standing enmity dating back to the "big four" days twenty years earlier, who are the ones who like to pretend that BR wouldn't have had the petty divisions and squabbles that the current privatised model has... let's not bother, eh?)
