High Speed Two (HS2) discussion

[Batman]

At the moment it's all my fantasy, but is has good foundation in proposals mentioned by the DfT and Network Rail, "Sending WCML services" down through Crossrail.

From what I have read of the likes of Crossrail 2, this would be running from Clapham Junction onto the Lee Valley Lines out of Liverpool Street, and won't be touching Ex. Euston services.
In addition to this, the pressure is needing to be taken off Euston ASAP, and the Crossrail 1 lines at Old Oak Common can easilly be linked for something under the £100m mark into the WCML via Willesden Junction, using the southernmost set of lines, making use of the current underpass at Wembley, with the extension of the F Sidings and an additional bridge to access the DC lines I'm estimating at under £50m, the expensive part of linking in the DC lines would be all the platform extensions required.

Regarding 'overloading' the number of passengers being taken away from Euston directly is not THAT significant, but the problem can come from loadings in central London stations in the evening peak, as they may be waiting on platform for up to 15mins for a service, with differing services running out of the Western end of Crossrail.

Now, this will be a problem whatever happens, the Eastern end shouldn't have too many problems with only two destinations and standard calling patterns, but the Western End will have groups of 4tph service groups. Such as 4tph to Heathrow, 4tph to Maidenhead, 4tph to Slough etc. One would hope this would give a standard set of Calling Branches, each running at 4tph, shown on the crossrail map.

The same deal with Thameslink, I can see massive problems with platform crowding, but with regards to on train crowding, I can't see this happening as much as platforms, but the timetables need to run properly.

Say for example, we have this kind of core 4tph patterns, with each 'route' running at a minimum of 4tph.

So on the Western End, we'd have: (Assuming a Reading extension, and West Drayton being dropped, or enhanced)

4tph Heathrow Airport (All with the same calling pattern)
4tph Maidenhead (All with the same calling pattern)
4tph Reading (All with the same calling pattern)

Giving 12tph.

Then over to the WCML

4tph to Tring, possibly terminating 2tph at Watford Junction.

Overall now having 16tph, still with 8tph to assign from the core 24tph.

So we could use West Drayton for another 4tph, send services via Northolt and electrify the Chiltern to High Wycome for 4tph, or use the DC lines for 4tph.

Basically, we need platforms big enough to store 6 trains worth of passengers that will be travelling beyond Old Oak Common, or if only 4 groups will do this and 2 groups will terminate at Paddington or OOC, then 4 trains worth of pax travelling beyond OOC. With an assumed capacity of each train being 1000 pax, but only approximately half of these (pure estimate) travelling beyond Paddington, we'd need platform space to store some 2000 passengers and enable flow of all core station passengers that don't care what train they're getting on.

Now, one could reduce the 'standing passengers' by having more services, running onto the outer core routes, for example:

8tph will run to Airport Junction and 8tph to Watford Junction, with the majority of commuting passengers jumping ship before the end of these outer core sections, meaning that the core station platforms will only need to hold two or three units worth of passengers, with the only people needing to wait for more than 7.5mins being those travelling beyond the outer core stations on each branch.

Either way, I fear I've lost most people here and any further discussion will be by prompt.

And finally, I'm not worried about Central London capacity any more so than that of the Thameslink Network...

Again sounds like good stuff. Is this intended to be in place of Crossrail 2&3 or alongside it. I.e, will the number of passengers it removes from Euston be greater than the number of passengers introduced by HS2?

I'd forgotten about how close Old Oak Common will actually be to Willesdon junction, so it should be done for less than £1bn.

And is there enough capacity on the Chiltern line to run an extra 4tph to High Wycombe and will it require loops at some station or full scale 4 tracking? And would those service be ones diverted from Marylabone?

And there would be some passengers waiting at central London cross rail station for upto 30 minutes in the evening peak because you've only got 2tph running to Tring, and on the High Wycombe branch, I doubt you could justify more that 2tph calling at Denham, Denham Golf Club and Seer Green even in the peaks.

So let's see if I've got this right. From central London crossrail stations, heading west in the evening peak there would be;

4tph to Maidenhead.
4tph to Heathrow.
4tph to Reading.
4tph to High Wycombe.
4tph to Wembley Central.
6tph tp Watford Junction (4 stopping, 2 semi-fast)
2tph to Tring.

And as a quick post script, electrification from Ruislip to High Wycombe would do wonders to the business case for electrifying the rest of the Chiltern mainline.

 

[Nym]

Eeeerrrr....

Something like that, if I was setting up the timetable from near scratch it would look something like this for the 4tph service groups (all services would be within a 4tph service group and depart at the same xx:nn, xx:nn+15, xx:nn+30 and xx:nn+45 times for a regular service interval (similar to how the met line operates it's branches). This is after some more thinking...

Peak / Off Peak

Watford Branch:

4tph Tring (All AC Slow Stations) / 2tph Tring & 2tph Watford Junction (All AC Slow Stations)


"Brunel" Branch:

(Note, I AM using the specified service levels to work this out, and some semi sensible headways, perenthesis indicate peak only calls.)
Crossrail Spec Base: 4tph Maidenhead, 4tph Heathrow, 2tph West Drayton

4tph Heathrow (Connect): Paddington, OOC, Ealing Broadway, Southall, Hayes and Harlington, Heathrow Central, Heathrow T4 (Peak), Off Peak all stations.
4tph Maidenhead: Paddington, OOC, (Ealing Broadway), Hayes and Harlington, West Drayton, Iver, Langley, Slough, Burnham, Taplow, Maidenhead
4tph Reading: Paddington, OOC, Ealing Broadway, Hayes and Harlington, Slough, Maidenhead, Twyford, Reading.
4tph West Drayton (Peak Only): All stations from Paddington.

That leaves 4tph to send somewhere, now, I'm of the opinion that Crossrail with 16tph on the Paddington Slows will shove it to capacity in the peaks, off peak dropping to 12tph (and 20 or 16tph in the Crossrail Core anyway).

The remaining 4tph, could form the DC line services as previously discribed, but would require platform extensions on this route, but IMO wouldn't be able to justify the electrification of the Chiltern Line from Northolt on their own, if the core was to run at 28 or 30tph (not inconceivable) then the intergration of a chiltern line or two at 4tph each (possibly Ammersham & Alyesbury) would be a nice option.

The Eastern end I am tending to ignore at the moment, as we are all aware that one can push 16tph on each of the pretty isolated Eastern Branches allowing disposal of 32tph from the core with ease, especially the Abbey Wood branch that remains an isolated network with two terminating platforms available, and additional platforms to send services onwards to Gravesend (and one would hope, intergrating with Ebbsfleet International by moving walkway from Northfleet station) providing better interchange with HS1 and HS2 (at OOC) for Crossrail, allong with the inclusion of the ovious facilties at Stratford International, also acting to provide a P&R facility (if 8tph where to continue from Abbey Wood to Gravesend via Ebbsfleet) for the Docklands and City at Ebbsfleet, with shiney new rolling stock...

Again, long post, sorry...

EDIT: As you can proberbly tell, I do put a fair amount of thought into these posts, and it's nice to know someone does actually make it to the end of them sometimes, and apologies for the poor spelling, the spell checker is being installed, I promise.

PS: It would be in addtion to Crossrail Two, I can't see Crossrail Three happening until after HS2 is open, one major project in london at once (ex. HS2) so if we have Crossrail One doing the WCML, GWML and GEML Inners with the Abbey Wood Branch for good measure, I was under the impression that Crossrail Two would be taking services from Clapham Junction and tunneling via Euston onto the Lee Valley Lines. Working off this publication http://www.transportxtra.com/magazines/local_transport_today/news/?id=28776 and the 2011 LSE RUS from NR.

I think the recent changes to the route to include Euston are causing confusion for many, not just on this forum, but the route will remain safeguarded as Chelsea - Hackney (Clapham Jcn - Lee Valley Lines) but will be diverted in Central London to include Euston as a calling point.

 

[Batman]

Ok, this is all getting a bit complex now when it come to deciding which projects should be given priority, so probs best if we leave it to the politicians. But I do think that at least some crossrail/LU projects should be linked in with HS2 and should be treated as a higher priority then the HS2 extensions to Manchester and Leeds.

 

[HSTEd]

I know the consensus is that a HSL to Scotland via Newcastle would have trouble building an economic case because the modal share of rail is already sufficiently high that additional traffic from eliminating aerial travel on the Scotland-London route would be insufficient to fill the several 400m trains per hour neccesary for the project to break even.

But what about offering lots and lots of marginal cost seats to try and break the express coach market and reduce the demand for car journies in the north east?

Since we would have at most 4tph to Scotland and Newcastle you could build a Shinkansen style line with stops every 20 or so miles without interfering with high speed operations.

You could essentially eliminate the ICEC franchise from the ECML north of York, and that would allow all sorts of interesting things to happen with freight and local trains.

 

[mr_jrt]

Nym - Nicely thought out work there.

I'm a big fan of the Chiltern options but I agree that they wouldn't fill up straight away. I do feel that there is suppressed demand though, and I think that patronage would build up enough to justify 6-8tph over a few years, but I'd minimise the dedicated infrastructure connecting to the WCML (i.e. make it as cheap as possible and live with the compromises) as I think there's scope to run out of capacity once patronage on the GWML and the other branches pick up, and there are other options for the WCML which the Chiltern and GWML routes just don't have, (i.e. a CR3 tunnel to Waterloo).

I suspect the DC lines option would probably cost just as much as the Chiltern one though - you'd probably have to re-electrify it with AC (unless you accepted dual voltage operation), you'd have to lengthen all the platforms, and resignal everything, which are largely the issues with the Chiltern route. It's far more likely that they would just hook up to the slow lines instead as you'd be pretty much good to go on day one.

On a tangent, there's an interesting opportunity that would present itself over time for a DC Watford Junction - Primrose Hill - Dalston Junction - Peckham - Clapham Junction - Hampstead Heath - Dalston Kingsland - Stratford spiral, serving both Willesden and Dalston (tenuously) twice. It's obviously a tad long though, and even the shorter route of Watford - New Cross is still quite long, so lopping off Wembley - Watford and giving Crossrail north of there is an interesting thought for both of those concepts.

Anyway, cheers for the posts, I found them interesting.

 

[D365]

Is there actually any need for Crossrail 3, at least in terms of diverting Watford DCs through Euston, when services could be taken over by Crossrail 1 and Bakerloo services. Crossrail stock, like Thameslink and most modern EMUs, are DC compatible.

A lot can be done with 16tph spare (up to 28tph 12 car if upgraded) spare on the western side. We need to think outside the box, like Nym

 

[Nym]

A lot can be done with 16tph spare (up to 28tph 12 car if upgraded) spare on the western side. We need to think outside the box!

I have been...

We don't need a "Crossrail" to feed into the Euston lines, as it can be taken by XR1, as can the Chiltern lines.

Just to go round the circle line...

Paddington: Crossrail One Confirmed
Marylebone: Crossrail One Possible via Old Oak Common
Euston: Crossrail One Possible via Old Oak Common (Linking in at Willesden Junction)
St Pancras: Thameslink
Kings Cross: Thameslink
Moorgate: (No issues, or Thameslink)
Liverpool Street Lee Valley / Anglia Lines: Crossrail Two
Liverpool Street Stratford Lines: Crossrail One Confirmed
Waterloo: Crossrail Two
Victoria, London Bridge, Blackfriars, Cannon Street, Charring Cross: Thameslink

The only station not linked by a CLRL (Cross London Rail Link) after Thameslink, Crossrail One and Crossrail Two (Clapham Junction to Lee Valley, possible extras at each end) will be Fenchurch Street... (As far as I know)

 

[Waverley125]

I'd think with regard to the 16tph spare there might well be 'express' services running out to Heathrow from a turnback on the Eastern side. Also, there are plenty of branches that could be incorporated into Crossrail. Greenford, Marlow, Heathrow, Windsor & Eton Central, Henley & Reading could all be termini. At 4tph that's 24tph right there. Not only that, but the NNML could be converted to XR use, and run out to Gerrards Cross, taking over all stops on the Chiltern main line south of there.

 

[D365]

The problems I see with Crossrail taking over HEx are how ticketing would work (non-express passengers would have to be kicked off at Paddington or possibly OOC) and whether BAA would be prepared to give their own service up. I guess the 332s could be reformed and sold off to Northern if this does happen.

In terms of HS2, although this is a while into the future, I wonder how a HS service to/from Heathrow would operate.

 

[Waverley125]

tbh I'd expect it simply to work as Heathrow getting double-frequency trains with the same fare all the way through, rather than a premium on express tickets. Not only would it maintain an HX service, but it'd increase capacity on XRW, as the HX's could run on the fasts, rather than the dedicated XR lines.

The 332s would certainly be welcome in West Yorks, given they'd give us the rolling stock to operate most of the commuter lines into Leeds using electric traction.

 

[nerd]

http://www.liverpooldailypost.co.uk...-on-the-32bn-high-speed-track-99623-31869489/

Interesting that it would appear that there has been a continuing debate within DfT over the merits of a west-of-Stoke and east-of-Stoke alignments for Phase 2. We know that HS2 lted prefered east-of-Stoke - shorter overall, quicker to Manchester; but it seems that ministers (or maybe just Greening) were attracted by west-of-Stoke - quicker to Scotland.

It seems that someone may be looking to bounce McLoughlin into a west-of-Stoke announcement.

 

[HSTEd]

Because there will ever actually be a HSL to Scotland via Carlisle >.<

They throw away tangible benefits for benefits that make no sense.

 

[Chris125]

A lot can be done with 16tph spare (up to 28tph 12 car if upgraded) spare on the western side. We need to think outside the box, like Nym

It needs to be remembered that the GWML relief lines will have to be shared with other services including freight and wont be fitted with ATO - extending services turning back at Paddington will almost certainly require a dedicated pair of tracks. That may be possible as far as OOC but unlikely much beyond there.

Because there will ever actually be a HSL to Scotland via Carlisle >.<

They throw away tangible benefits for benefits that make no sense.

I think the idea is a west-of-Stoke route would be quicker for trains to Scotland (and Liverpool) via the WCML.

Chris

 

[LNW-GW Joint]

http://www.liverpooldailypost.co.uk...-on-the-32bn-high-speed-track-99623-31869489/

Interesting that it would appear that there has been a continuing debate within DfT over the merits of a west-of-Stoke and east-of-Stoke alignments for Phase 2. We know that HS2 lted prefered east-of-Stoke - shorter overall, quicker to Manchester; but it seems that ministers (or maybe just Greening) were attracted by west-of-Stoke - quicker to Scotland.

It seems that someone may be looking to bounce McLoughlin into a west-of-Stoke announcement.

The Post has a biassed view (what would you expect?) but if true seems to mean that they intend to follow roughly the current WCML alignment to Crewe and Manchester, thus avoiding much of the outcry about a new route.
There would have to be a new route Armitage-Norton Bridge to avoid the existing sinuous route through Stafford, but from there onwards it's pretty straight.
A Crewe bypass towards Manchester might be needed.

 

[nick.c]

West of Stoke would certainly attract fewer environmental objections. I think that Network Rail had roughly mapped out a 14 mile Stafford by-pass, now replaced by the Norton Bridge development, that could be used. West of Stoke would also make a Stoke / Crewe regional station easier to develop.

 

[Waverley125]

West of Stoke will allow trains to reach Liverpool faster, and, in all honestly, there bloody well ought to be an HS spur into Liverpool as well as Manchester.

As for going to Scotland via Carlisle, I'm not sure this is as far-fetched as some suggest. If the route was to have a 'South Manchester' (i.e. Manchester Airport) station, bypass Manc City Centre to the West, then have a 'North Manchester' (i.e. Preston) station to serve both urban Lancashire & northbound passengers out of Manc.

There's then a 90 mile run to Carlisle, possibly with a station at/Near Kendal 'Lake District Parkway' halfway, and a 95 mile run to Glasgow. At an average speed of 200mph, a non-stop Glasgow-Manchester run would take just over an hour, against 3 hours now, while a stopping run would take maybe 90 minutes. Huge benefits to North Cumbria & the borders, as well as making the lake district a lot more accessible, and allowing quick commuter flows into Manchester & Glasgow from Carlisle.

 

[nick.c]

A few years ago Greengauge21 commissioned a study by MVA into Anglo-Scottish route options, and a "West Coast" route appeared to be the best option as it would serve Glasgow and Edinburgh equally well and could use substantial stretches of (upgraded) existing infrastructure.

 

[HSTEd]

A few years ago Greengauge21 commissioned a study by MVA into Anglo-Scottish route options, and a "West Coast" route appeared to be the best option as it would serve Glasgow and Edinburgh equally well and could use substantial stretches of (upgraded) existing infrastructure.

For the anglo-scottish route in isolation it is the least worst option.

But unfortunately very few people live between Manchester and the Scottish Central belt. The only route for which you can patch together a business case is the east cost, because there are several million extra people there who can have journies on the system too.
--- old post above --- --- new post below ---

West of Stoke will allow trains to reach Liverpool faster, and, in all honestly, there bloody well ought to be an HS spur into Liverpool as well as Manchester.

As for going to Scotland via Carlisle, I'm not sure this is as far-fetched as some suggest. If the route was to have a 'South Manchester' (i.e. Manchester Airport) station, bypass Manc City Centre to the West, then have a 'North Manchester' (i.e. Preston) station to serve both urban Lancashire & northbound passengers out of Manc.

There's then a 90 mile run to Carlisle, possibly with a station at/Near Kendal 'Lake District Parkway' halfway, and a 95 mile run to Glasgow. At an average speed of 200mph, a non-stop Glasgow-Manchester run would take just over an hour, against 3 hours now, while a stopping run would take maybe 90 minutes. Huge benefits to North Cumbria & the borders, as well as making the lake district a lot more accessible, and allowing quick commuter flows into Manchester & Glasgow from Carlisle.

Unfortunately few people live in North Cumbria and that side of the Borders, whereas an East coast route starting in Leeds can tap the rather large populations in the North East such as on Tyneside and Teeside.

 

[nick.c]

If my memory is correct the Greengauge21 research identifying that the "West Coast" route appeared to be the best option for an Anglo-Scottish HSL reached that conclusion despite the relative paucity of people living in Cumbria and the Scottish Borders.

 

[ainsworth74]

That depends on what criteria they're using to determine the best option. If they're looking purely at Anglo-Scottish traffic then the West Coast probably is better.

 

[HSTEd]

If my memory is correct the Greengauge21 research identifying that the "West Coast" route appeared to be the best option for an Anglo-Scottish HSL reached that conclusion despite the relative paucity of people living in Cumbria and the Scottish Borders.

Greengauge 21 also posits that there would be sufficient demand in Newcastle and the like to support a HSL to Newcastle anyway.

It is highly unlikely however that you could build a business case for a Newcastle route in isolation of Scottish traffic, which means you go via Newcastle or HSR does not secure that business at all.

 

[MidlandMainlie]

Greengauge 21 also posits that there would be sufficient demand in Newcastle and the like to support a HSL to Newcastle anyway.

It is highly unlikely however that you could build a business case for a Newcastle route in isolation of Scottish traffic, which means you go via Newcastle or HSR does not secure that business at all.

The report is here if anyone would like to read it

http://www.greengauge21.net/publications/fast-forward-a-high-speed-rail-strategy-for-britain/

What they argued for was a HSL duplicating the WCML all the way to Edinburgh and Glasgow, followed eventually by a second HSL via Cambridge, Nottingham, Sheffield, Leeds and Newcastle with extra services running along an upgraded ECML to Scotland. With planning of the Y network for HS2 this second HSL will never be built as Greengauge have proposed (IMO if HS rail ever is built to Scotland and if more services are needed to be run in the future than can be accommodated on the Core of the Y than a second alignment following the M1 should be built to link up with the eastern arm of the Y south of East Midland Station (possibly with a parkway station near Leicester)).

 

[nick.c]

Agreed....Irrespective of whether future HS Anglo-Scottish services should be routed along the West or East coasts (or some other alignment) - perhaps a more important issue is whether there needs to be a second north - south HSL from London joining the HS2 Eastern branch somewhere in the East Midlands. Unfortunately the current HS2 Phase 2 proposals only allow for 6 tph from London along the north eastern branch - and most of these will serve Leeds and Newcastle. The result is that Nottingham, Derby and Sheffield will lack frequent direct HS services to their city centres - and of course Leicester will be missed entirely.

A second HSL could solve this - and I'm sure will be built if HS2 proves to be a success.

 

[tbtc]

Unfortunately few people live in North Cumbria and that side of the Borders, whereas an East coast route starting in Leeds can tap the rather large populations in the North East such as on Tyneside and Teeside.

...but as I've said before, by the time you start trying to serve Teesside and other places then you lack the "High Speed" aspect - compared to running fast up the west (the lack of people living nearby isn't an issue if you are trying to build a High Speed line - otherwise why not stop several times between London and Birmingham?)

 

[HSTEd]

...but as I've said before, by the time you start trying to serve Teesside and other places then you lack the "High Speed" aspect - compared to running fast up the west (the lack of people living nearby isn't an issue if you are trying to build a High Speed line - otherwise why not stop several times between London and Birmingham?)

The reason that stopping several times between London and Birmingham is impractical is not because that would stop it being high speed, but because it would kill capacity on such a heavily loaded line.

A HSL to scotland would have far fewer trains on it and would be able to operate stopping and fast trains very easily, with the "stopping" trains still being faster than the conventional "fast" trains, this is what Shinkansen do every single day in Japan.

(We would be down to about 9tph at most on the HSL to Scotland, which is Shinkansen level traffic densities)

 

[Invincibles]

They do similar in China with no problems, in many cases the slower trains are marketed as such (with cheaper tickets).

However all trains are run with stock capable of doing 300kmph and as such when the "slow" trains are out on the running lines they do not obstruct anything else.

I will still contend we ought to be looking at skip stops to allow stations every 20 miles or so, with very few trains making a 100 mile run with no stop (rather like Shanghai to Nanjing is only done non stop once an hour - most trains stopping two or three times)

I would suggest 1 fast train to Edinburgh and 1 to Glasgow with stops at Birmingham and Manchester only is enough. Indeed they could even alternate with the other making stops at "Stoke" and "Carlisle" as well as something in the Chilterns.

I am not convinced that a line terminating in Newcastle would not be viable, given a similar construction of skippable stops between Newcastle and Leeds there are a lot of places to be served.

 

[Waverley125]

as has been said, the East & West Coast alignments are not competing with one another.

Leeds-Newcastle-Edinburgh will provide for fast journeys between those three cities, as well as Newcastle & London, will relieve the northern ECML (great news for Middlesborough, Northallerton, Darlington, Sunderland, Morpeth & stations north of Newcastle).

The Western alignment will allow for the fastest possible trains between London & Scotland.

As for the 'other lines' the projects I see being worthwhile are

Two Cities: Glasgow-Edinburgh
East Coast: Edinburgh-Dundee-Aberdeen
Triangle: Glasgow-Dundee
Birmingham Avoider: Nottingham-Chilterns avoiding Birmingham.

That's basically all done for the North, then you're looking at going to Bristol & Wales, as well as Exeter, Plymouth & Cornwall.

 

[Joseph_Locke]

Err, can I just observe that 200mph running Manchester - Glasgow without tilt (as the HS2 stock is advertised to be) on the current route will require a completely new alignment from Farnworth to Euxton, through Preston, most of Carnforth to Carlisle and most of Gretna to Glasgow.

How is this good?

 

[HSTEd]

as has been said, the East & West Coast alignments are not competing with one another.

Leeds-Newcastle-Edinburgh will provide for fast journeys between those three cities, as well as Newcastle & London, will relieve the northern ECML (great news for Middlesborough, Northallerton, Darlington, Sunderland, Morpeth & stations north of Newcastle).

The Western alignment will allow for the fastest possible trains between London & Scotland.

As for the 'other lines' the projects I see being worthwhile are

Two Cities: Glasgow-Edinburgh
East Coast: Edinburgh-Dundee-Aberdeen
Triangle: Glasgow-Dundee
Birmingham Avoider: Nottingham-Chilterns avoiding Birmingham.

That's basically all done for the North, then you're looking at going to Bristol & Wales, as well as Exeter, Plymouth & Cornwall.

Building one HSL to Scotland is a dodgy proposition, building two is Ludicrous, there is just not enough traffic. (Two trains per hour to Newcastle, one to Edinburgh on the East Coast and then one to Glasgow on the West Coast?)

For the cost of increasing the Glasgow travel time by just eleven minutes a route up the East Coast gets you a high speed rail link between Edinburgh and Glasgow and to Newcastle almost for "free".
The amount of track you actually need to build only increases by about 20 miles because there are no branches.

NOTE: Multiple units in the Shinkansen/395 style with N700 level top speeds could do the Edinburgh-Glasgow run in about 19 minutes non stop, or 24 minutes with an intermediate stop at Falkirk or similar.
Which rather changes the nature of the Central Belt in my opinion.

 

[Waverley125]

And then, remembering that some trains don't actually go to London

1tph Sheffield-Newcastle (XC)
1tph Leeds-Newcastle (XC)
1tph Leeds-Newcastle (TPE, thought to increase to 2 with additional paths through Huddersfueld)
1tph Manchester-Glasgow*
1tph-Birmingham-Glasgow*

*and consider demand to run both hourly to Edinburgh as well.

So let's call that a starting out point of 5tph on the NW arm and 5tph on the NE arm.

plus greater demand for both London-Newcastle, London-Glasgow and London-Edinburgh train travel as the train, at 2.5 hours approx, becomes much faster than air travel on centre-to-centre journeys.

It's not lunacy to accept that the northern and southern halves of an HSL to Scotland are motivated by different objectives and benefits. The southern half is all about capacity, freeing up paths on already well-used journeys. The northern half is about reducing journey times and encouraging modal shift from road and air to rail travel.