To save having the same discussion/argument with different people, here's my view of XC (and XC through Leeds in particular); feel free to shoot it down...
At the moment there are the following long distance services north of Birmingham each hour
- Nottingham
- Nottingham
- ECML via Doncaster
- ECML via Leeds
- Manchester
- Manchester
- WCML via Wigan
- Liverpool
- Liverpool
...so that's
nine trains per hour to the north
At the moment there are the following long distance services south of Birmingham each hour (excluding London services):
- Bournemouth
- Reading (bi-hourly to Southampton)
- Plymouth
- Exeter
- Cardiff
...so that's
five trains per hour to the south
I'm not including the TfW services (since they were never Cross Country and are never going to be integrated with non-Welsh services) or the Leicester - East Anglia services (again, never Cross Country under BR, don't run cross-Birmingham)
Some of the services are part of the "proper" XC franchise, some of the services are part of the "ex Central Trains" franchise ( some people don't like to think Nottingham - Cardiff as "real" XC), some of the services are ones which were part of XC at one stage (Liverpool, WCML via Wigan).
There are also some places that
had a direct Birmingham service post-privatisation but no longer have a direct Birmingham service under any operator (Bolton, Swindon, Brighton, Gatwick, Ramsgate etc)
So there's a clear imbalance between north and south. Everything becomes a zero-sum-game. If you are keeping everything simple clock face hourly (which seems necessary on today's modern railway - we can't fit lots of randomly timed paths through New Street.
Some of the services have changed several times - e.g. Virgin settled down to 3tp2h on the Newcastle - Bristol corridor and 3tp2h on the Manchester to Reading corridor, with a bi-hourly Newcastle - Reading service and a bi-hourly Manchester - Bristol service - but at other times there were no Mancehste trains to the South West as 75% of Bristol trains were to/from Newcastle and the other 25% were "WCML via Wigan". Links between places hundreds of miles apart were chopped and changed and the world kept turning.
If there are going to be five long distance trains per hour from one side of Birmingham to the other then some places are going to miss out entirely (e.g. currently Liverpool) whilst other places are limited to just one destination (e.g. Doncaster only has trains towards Reading, Nottingham only has services towards Cardiff).
For example, all Leeds services currently go to Plymouth, all Doncaster services go to Reading/ Southampton, no Yorkshire services go to Coventry or Bournemouth - that's just how it is - it's not because Reading people prefer to go to Doncaster than to Leeds, it's just a case of tying up two paths at Birmingham. I think that some people assume that, because a service links two places, there must be significant demand between two places, rather than just operational convenience
Look at Metrolink; there's no reason for the Oldham services to go to the Airport/ Bury/ Media City, it's just that there are a certain number of paths through Victoria and a certain number of paths through Cornrbrook and a certain number of paths through Piccadilly Gardens - but the number of people doing journeys like Ashton to East Didsbury will be pretty insignificant).
Same with TPE - there's no reason why Scarborough trains go to Liverpool rather than Manchester Airport or terminating in Piccadilly, or Middlesbrough trains go to the Airport rather than Liverpool or terminating at Piccadilly, or Hull trains just terminate at Piccadilly rather than extending to the Airport or Liverpool... it's just that there are long distance five trains per hour through the "core" and that's how the cookie crumbled
BR provided a lot of links, but BR had space on emptier lines to do these things. Like the way that they ran some Newcastle - Birmingham services via both Leeds and Doncaster (nice to have direct links to lots of places, but not very fast for longer distance passengers). But then BR used to do things like running Glasgow - Portsmouth via Liverpool (which is another awkward time penalty but presumably ticked a lots of boxes). We don't have space to do this kind of thing nowadays, we have clock face patterns on most lines so any XC services need to fit in around these - e.g. there's only one path an hour through Leeds at the moment so if you have an hourly service from/via Leeds to Birmingham then it can't really serve Gatwick/ Bournemouth/ Plymouth/ Cardiff - BR tried to maintain all of those links but it isn't feasible (in the way that Manchester Metrolink wouldn't work if you tried to give Oldham an hourly service to the Airport/ East Didsbury/ Eccles/ Trafford Centre etc)
We keep having these threads where people obsess about the links between places hundreds of miles apart, as if there's some huge reason why (e.g.) Leeds needs/ "deserves" a direct hourly service to (e.g.) Plymouth. IMHO the passenger numbers between Edinburgh/ Glasgow/ Newcastle/ Leeds/ Doncaster/ Manchester/ Liverpool etc and Bournemouth/ Plymouth/ Cardiff etc will be so low that it doesn't matter whether the hourly Leeds service ties up with the hourly Bournemouth service or the hourly Plymouth service or the hourly Cardiff service
Long distance journeys are great, but a lot more people do journeys of under ninety minutes - maybe you don't like the idea of an "InterCity" TOC doing something as mundane as Leeds to Sheffield (though these are, erm, cities), and we should skip various intermediate stations, but there's no necessarily going to be additional paths to replace the local links, and you'll just hit the next bottleneck, so your suggestion for avoiding Tamworth/ Burton/ Chesterfield etc will just mean an extra five/ten minutes waiting at Sheffield for the existing path north, whilst inconveniencing people at Tamworth etc.
XC have stated that Leeds - Sheffield is their busiest section (when applying for at least some of the "via Doncaster" services to be diverted via Leeds) - as someone who used to commute on that service etc day, I have no reason to doubt them! But Sheffield commuters like me or Leeds people wanting to use their only link to the Midlands are fighting for seats with longer distance passengers - running the Edinburgh trains via Leeds is a regrettable step, since it means a slower journey for Glasgow/ Edinburgh/ Berwick - Sheffield/ Derby/ Birmingham journeys (twenty minute time penalty) as well as pushing those passengers onto the already-busy Leeds service. Normally, if you've got two trains per hour on a route you try to balance out the passenger numbers (e.g. the Waverley - Falkirk High - Queen Street services generally stop at either Linlithgow *or* Croy, rather than one doing both stops which would mean unbalanced durations leading to unbalanced departure times and unbalanced passenger numbers)
So, do you run both services via Leeds (which would balance journey times to make it half hourly south of Newcastle, but mean all Newcastle/ York - Sheffield/ Derby/ Birmingham journeys are the longer of the two durations - and keep clogging up the ECML north of York - but you'll struggle for paths east of Leeds - maybe you'd have to cut at least one of the TPE services on that section)?
Or run both services via Doncaster (which would mean a half hourly service south of Newcastle and all journeys at the shorter of the two durations, but removing West Yorkshire from the XC map and leaving the West Yorkshire - Sheffield/ Midlands passengers crammed onto a Northern 158?).
Or extend the "via Donny" service to Scotland whilst cutting the "via Leeds" service at Leeds, thus putting all the Edinburgh/ Newcastle passengers on the Doncaster service, freeing up a lot of seats for Leeds passengers (esp as you'll free up around three Voyagers)?
I'd go for the third option - it's not perfect but it removes trains from the sections with too many
trains per hour (east end of Leeds, ECML north of York) and puts more seats on the section with too few
seats per hour. What's the alternative? Keep cramming long distance passengers through the east end of Leeds and on the busiest bit of the franchise through Wakefield whilst we wait for the eastern leg of HS2 to be built? Well, I admire your optimism...
I often wonder if XC could avoid Sheffield altogether and go via The Barrow Hill Line to Leeds or Doncaster?
I wonder what the time saving/penalty would be for that?
(I genuinely don't know - it's more direct to go straight down the Rother Valley from Chesterfield to Rotherham but I don't think it's a particularly fast alignment - but even if it wasn't, the crawl into/ through/ out of Sheffield Midland must be painfully slow for some longer distance passengers - I'm "lucky" in that I only see one side of it on my journeys)