If you bypass cities, you have to run more services. That it's more efficient to run HSR services isn't relevant here when comparing your point-to-point approach against what I'm discussing.
Actually it is
very relevant - because the costs of running a set have now dropped sufficiently that the capital cost of the infrastructure is the dominant factor.
Which means we can trade off lower set effficiency in favour of greater efficiency of capital investment and still come out with a net gain.
For example, in your idea, you would use something like a Class 395 Javelin as the 'HS3' train and have >2tph between each city pair. The staffing costs of a single Javelin carrying ~300 people isn't any different to the cost of staffing a 200m set carrying 550 people or, with DOO, a 400m set carrying 1100 people. You need more trains and more crews to move the same number of people (read: ticket fares and economic impact) yet individually, each city pair gets a worse service.
You would likely use something like the 100m set from CAF (the
Oaris) rather than a Javelin for reasons that I will soon demonstrate.
Let's say you have four northern city complexes (Liverpool, Manchester, Leeds, York/Newcastle (as York can certainly be a through station it can use Newcastle trains)). All of those can only be practical as termini - Liverpool and Newcastle because they are ends of the line, Manchester because it can either use the HS2 approach at zero cost or because it will need two billion pound+ tunnel approaches and a hugely expensive new station (as Victoria is kind of stupid because it would miss out on major connectivity at Picadilly) and finally Leeds because there is nowhere near enough spare capacity on the eastern approach, again neccesitating massive tunneled approaches and a new station location that can be avoided if you simply use the HS2 approach and the HS2 York access spur.
If we take these four termini - and you want to go excessive and have four trains per hour between every pair - this will require you to have 12tph into each termini - still within the likely capabilities of the HS2 approaches at Leeds and Manchester and thus requiring no additional infrastructure at those sites beyond some new platforms that if specced in now can be relatively inexpensively included in the new stations being constructed.
Additionally the number of actual sets required for this enormously intensive timetable is not necessarily as large as it appears - as Liverpool-Newcastle/York trains would stop maybe twice during their journey (York and Manc Airport for example) they could keep up to speed for long journeys and thus could utilise higher speeds than 230km/h practically.
With clever design of the infrastructure the trains could access the 'unlimited speed' route which could be arrnaged along the HS3 corridor without disadvantage to HS2 trains. 320km/h would be easily achievable, which means Newcastle-Liverpool journey times of an hour are within reach.
And with lower capital costs than the through route proposal that requires lower speeds.
All this will reduce the number of trainsets required and the number of vehicles required to a level comparable to using longer trains on 'strung together' journeys - I will spec an example timetable to demonstrate this if you give me a couple of hours.
We also have to spec for the enormous transport growth that will occur between these cities once the system is in place - it gets to the point that the Universities of Manchester, Leeds and maybe even York could merge into a single multi campus university and have students commute between them.
If you string together services such as Liverpool-Manchester-Leeds-Newcastle, the number of tph that you need to run to move the same number of people will reduce, thus reducing operating costs. At the same time, that reduced operating cost, and need for fewer trains, makes it much easier to increase frequency once passenger loadings require it, as each extra train per hour's capacity can be shared by a small increase in numbers of people going to each individual city along the route. If you've got a 3tph point-to-point service from Liverpool to Leeds, for example, then you need to wait until there is an absolute need for 4tph on the Liverpool-Leeds line alone before you can increase frequency. Frequency is probably going to be the single most important aspect of the HS3 idea, as there is no point in there being a fast route if the trains don't come frequent enough to make any appreciable difference in total door-to-door journey time.
But frequency is cheap thanks to the enormous train/hour capacity available to modern railways and the fast cycle times of trains and crews thanks to the high speed.
It will not be able to overcome the titanic capital costs. (Which still have to be paid back over the trial period even if they are near zero interest, as they are now).
The Government has basically infinite money to spend on worthwhile investments. This is why it can afford Crossrail 1, which has a huge upfront cost but one that is necessary for the scheme to work. They could have saved billions off the cost by making different decisions but these decisions would then have made the line work less well, and meant less economic return. There is nothing impossible about getting a proper HS3 route sorted that will run through the middle of Manchester and Leeds. Thankfully, unlike HS2 or Crossrail, it will be possible to stage the work so that benefits can be seen more quickly and more cheaply without harming the long-term efficiency of the idea. The first stage could be to build a new pair of tracks from the east of Victoria to wherever in Leeds it would be possible to connect into the existing lines and use existing stations. Then you just link up other sections of the route, like from Liverpool to west of Victoria, allowing 'HS3' services to spend more and more time on dedicated tracks at higher speeds. Once the time is right to rebuild Victoria, it can be done to provide that set of segregated platforms for the 'HS3' services.
But, despite low interest costs, the capital repayments would be so enormous as to render the idea less beneficial than the point to point approach.
And capital costs have to be go through trial-by-media, which makes them very difficult to obtain.
EDIT: And here is a
very calculation I did for illustration purposes:
Crude drawing on a map generates these approximate distances for a Point-to-Point system:
Liverpool* - Newcastle > 287km - ~60 minutes each way - ~ 2.5 hour cycle time - 10 sets
Liverpool* - Leeds > 135km - ~40 minutes each way - ~ 2 hour cycle time - 8 sets
Liverpool* - Manchester > 75km ~ 25 minutes each way - ~ 1.25 hour cycle time - 5 sets
Manchester - Leeds > 90km - ~ 30 minutes each way - ~ 1.5 hour cycle time - 6 sets
Manchester - Newcastle > 220km - ~ 50 minutes each way - ~ 2.3 hour cycle time - 10 sets
Leeds - Newcastle > 160km > ~45 minutes each way - ~ 2 hour cycle time - 8 sets
Total: 47 sets - 188 vehicles
* Liverpool approach is northerly into Exchange simply because this is the approach I favour and no captive route seems to have won consensus - it is also rather cheap as it appears to requrie almost no tunneling at all.
If we go with the straight through approach we only have one train service:
Liverpool - Manchester - Leeds - Newcastle (via York) > ~270km.
Which is shorter than the point to point's longest stretch, but your travel time will be something like 2 hours end to end once you account for the lower speed running of the through line proposal and the multiple additional stops.
(That still has you averaging a similar speed to a WCML express - so obviously still fast).
That means you will have something approaching a five hour cycle time, requiring close to 20 sets.
So you appear to have a drastically lower set requirement (20 v 47), however you must fit everyone travelling east or west out of any city in the system into that one set, whereas the other spreads all the passengers across three.
So we willl (conservatively) increase the train length to 8 vehicles, which boosts your set equivalent requirement to ~ 40.
So you only save 17% of your rolling stock requirement.
Staff costs are actually largely negligible in a DOO operated ATO high speed system simply because staff costs generally on the railway are almost negligible.
In return for this modest increase in rolling stock costs and significant increase in staff costs I have slashed the capital cost of the project and shortened journey times significantly over the longer legs.