Could the Crossrail 2 route be improved?

[lukazade]

I recently read this blog post about an improved Crossrail 2 route, which is supposedly much cheaper to build. It seems to make sense to me, but this is real crayonista territory, so I'm wondering what people with actual railway experience think of the idea.

Crossrail 2 as currently planned doesn't seem to be going anywhere this half of the century, so should it be redesigned to save costs?

A better Crossrail 2

How to help London grow while saving money

springbett.substack.com

 

[HSTEd]

I can't see how this is going to be any cheaper than the proposed route.
The disruption and other costs from trying to rebuild Clapham Junction is going blow this scheme up by itself.

Plus the desire to permanently cripple the line through reuse of legacy infrastructure.

 

[Crithylum]

I don't see how Finsbury Park needs a forth (or fifth counting canal tunnels) connection to the area around St Pancras. I don't think another overlapping route would have a favourable CBR compared to upgrading the Piccadilly line. The Dalston plan would likely also alleviate Finsbury Park, as the Victoria line loses its Tottenham Hale/Seven Sisters monopoly on non-Liverpool Street central London destinations, as well as a TFL takeover likely resulting in ECML stopper improvements. However, XR2 is certainly not the cheapest way of getting more than 2tph to certain stations.

I strongly disagree that Finsbury Park is better for connectivity. Every new connection is just a duplicate (South Tottenham does not need XR2 to be rebuilt). Dalston would provide NEW useful connections. This would actually improve connectivity. Linked is a video roughly about this topic.

 

[Mr. SW]

I thought the whole idea of Crossrail 2 was to bring relief to the lines around Finsbury Park and Clapham Junction, not add to it.

This is very bad.

 

[cle]

I think the inclusion of Angel and Dalston or Hackney are also to 'share the love' to parts of London which are growing / very popular, but underserved. ELL/NLL links at Dalston give it the edge I think.

For that same reason, I'd be tempted to miss TCR and have a station at Holborn instead, before going direct to Angel. I am not convinced we need KXSP either. Or a Chancery Lane/Farringdon manifestation under Leather Lane, if a CR1 link is deemed essential - - - but spreading the benefits of transit across the CBD vs more concentration.

We'll end up with TCR, KXSP and Stratford having every link, and nowhere else seeing improvements, it's too concentrated. Nobody is now decrying the Victoria line/Oxford Circus miss of Crossrail, and very helpful that has been too.

 

[SynthD]

There are, somewhere, hundreds of pages of research into why the route is the best. As every suggestion here, including the blogpost, are near the route, I suspect they were considered and turned down for good reasons.

 

[Crithylum]

Nobody is now decrying the Victoria line/Oxford Circus miss of Crossrail

That is not my personal sentiment. However my "solution" would've been a travolator from the eastern end of Bond Street, given that Hanover Square exit is actually closer to Oxford Circus than Bond Street tube. Not really a proper additional station.

For that same reason, I'd be tempted to miss TCR and have a station at Holborn instead, before going direct to Angel. I am not convinced we need KXSP either. Or a Chancery Lane/Farringdon manifestation under Leather Lane, if a CR1 link is deemed essential - - - but spreading the benefits of transit across the CBD vs more concentration.

I don't think that Holborn would have a significant benefit, given that it is only 650m from TCR, so there would be some overlap in where they serve. Another factor is that the Piccadilly will be connected at St Pancras, and possibly Green Park, if scoped in. Personally I would value an XR1 connection much more, and I would expect that to be a more significant flow (although I don't have data to back that up).

My wildcard suggestion would be to scrap Victoria (and Chelsea), and instead have Green Park and Sloane Square. A southerly entrance to Sloane Square would serve a similar purpose to Chelsea station. It would make connections to Southeastern less convenient with an additional change at Green Park, but add connections to the Jubilee and Piccadilly lines. I guess it is a question of whether Victoria or Green Park spaghetti is worse. Although this scheme seems like a way of overcrowding the Victoria line. Maybe now that I think about it Victoria and Green Park would be best. Rambling over.

 

[cle]

That is not my personal sentiment. However my "solution" would've been a travolator from the eastern end of Bond Street, given that Hanover Square exit is actually closer to Oxford Circus than Bond Street tube. Not really a proper additional station.

I don't think that Holborn would have a significant benefit, given that it is only 650m from TCR, so there would be some overlap in where they serve. Another factor is that the Piccadilly will be connected at St Pancras, and possibly Green Park, if scoped in. Personally I would value an XR1 connection much more, and I would expect that to be a more significant flow (although I don't have data to back that up).

My wildcard suggestion would be to scrap Victoria (and Chelsea), and instead have Green Park and Sloane Square. A southerly entrance to Sloane Square would serve a similar purpose to Chelsea station. It would make connections to Southeastern less convenient with an additional change at Green Park, but add connections to the Jubilee and Piccadilly lines. I guess it is a question of whether Victoria or Green Park spaghetti is worse. Although this scheme seems like a way of overcrowding the Victoria line. Maybe now that I think about it Victoria and Green Park would be best. Rambling over.

For me, it's the walkable employment, and Sloane Square scores very low there - obviously plus the connections.
Especially if we are thinking fewer, double-ended stations, to increase catchment. Which is more obvious with longer trains.

Victoria extending to St James Park is interesting - as the Victoria Street area in between has a ton of employers, before you end up in a new sphere of a lot of Westminster jobs. I'd say you could close St James Park although the heritage people would shriek.

But I think serving Victoria from the South West - and Clapham Junction - will help the Victoria line itself massively. And having a Vic-Oxford St hop removes a large demand generator for the Victoria line at Victoria, probably a big single seat transformation vs a Victoria change. In turn, I think the Euston/KXSP complex would have plenty of capacity, especially if Euston Square was fully integrated to Euston LUL - to enable CR1 to maybe go direct to Angel from TCR and save a billion or two.

 

[Bald Rick]

Much of this was looked at, and found to be more expensive or effectively impossible.

Just one examl,e - its sounds simple to ‘rebuild Clapham Junction above ground’ - but the cost of that alone would be billions. Then there is the disruption on top. And then there’s the minor point that there’s nowhere to put a portal between Clapham Junction and Victoria.

 

[Mr. SW]

Getting around tunnels at Kings Cross and Victoria will force the line to go extremely deep. HS2 as planned will be deep enough as it is.

 

[carto_graph]

Author here! I've written two blogposts about this already, here and here that go into more detail about my crayon. Very happy to receive constructive feedback!

Responding to a few specific points:

I can't see how this is going to be any cheaper than the proposed route.
The disruption and other costs from trying to rebuild Clapham Junction is going blow this scheme up by itself.

Plus the desire to permanently cripple the line through reuse of legacy infrastructure.

There are four choices:

1. Don't build Crossrail 2, which is what we're currently doing.
2. Build Crossrail 2 but don't stop at Clapham Junction.
3. Build an underground station at Clapham Junction.
4. Use the existing above-ground platforms at Clapham Junction. This would entail severing the Croydon – Watford service that uses platforms 16 and 17. The five island platforms on the southern side of the station (7–16) would then have two tracks for each of: SWML fast; SWML slow; XR 2; BML fast; BML slow. Platform 17 would be put out of service. The tunnel portal to go to Victoria would probably be where the Parkfield Industrial Estate is.

I think we can agree that (1) and (2) are undesirable. So the question is, (3) or (4). In my view we should simply go with the cheaper. I suspect that redesigning the throat of CLJ is likely to be cheaper than a full-fat underground station, but very happy to be proven wrong!

Second, "legacy infrastructure" is a misnomer. I'm proposing re-using legacy alignments – when you've replaced all the track and all the signals the line is a bit of a Ship of Theseus. Today's SWML shares only the alignment in common with the line built in the 1800s!

In other words, if we can fit in extra tracks next to existing alignments, or in disused alignments, then we should do so unless tunnelling genuinely would be cheaper.

I don't see how Finsbury Park needs a forth (or fifth counting canal tunnels) connection to the area around St Pancras. I don't think another overlapping route would have a favourable CBR compared to upgrading the Piccadilly line. The Dalston plan would likely also alleviate Finsbury Park, as the Victoria line loses its Tottenham Hale/Seven Sisters monopoly on non-Liverpool Street central London destinations, as well as a TFL takeover likely resulting in ECML stopper improvements. However, XR2 is certainly not the cheapest way of getting more than 2tph to certain stations.

I strongly disagree that Finsbury Park is better for connectivity. Every new connection is just a duplicate (South Tottenham does not need XR2 to be rebuilt). Dalston would provide NEW useful connections. This would actually improve connectivity. Linked is a video roughly about this topic.

The reason to go by Finsbury Park rather than Dalston is simple: cost. This allows us to re-use the formerly six-track alignment north of the Copenhagen Tunnel. Rebuilding Finsbury Park (which has a disused platform on the western side) will obviously be disruptive and time-consuming, but it should be cheaper than building an underground station.

Going via Finsbury Park also makes it easier to relieve the Piccadilly Line without building underground stations at Wood Green / Turnpike Lane + Ally Pally. As long as London spends £800 mn on building a single Crossrail station, we need to be tight-fisted about doing anything underground.

There are, somewhere, hundreds of pages of research into why the route is the best. As every suggestion here, including the blogpost, are near the route, I suspect they were considered and turned down for good reasons.

If our institutions of government were competent, we would have Nordic infrastructure costs (or lower-than-Nordic costs, Denmark and Sweden's costs have been inching upwards in the last decade).

Less flippantly, everybody can agree on one thing: TfL have failed to get Crossrail 2 built, largely because it is so expensive. It's as much of a line on a map as my proposal.

I don't think that TfL were explicitly optimising for low costs, whereas I am. They might have been optimising for BCR, but that's conceptually very different: if a project costs £45 bn then it will have a BCR > 1 so long as it produces benefits greater than £45 bn. But that doesn't mean the Treasury will be willing to spend £45 bn, whatever the BCR.

In my view, costs are the correct thing to be optimising for. Given the political and institutional environment we're operating in, we won't get anything built unless we can bring construction costs down. We can't just blame "Treasury Brain" for blocking big rail infrastructure projects: yes, the Treasury's rules probably probably should be reformed, but we have to operate in the Britain we actually live in.

Again, happy to be corrected. If a TfL insider tells me that the decision-making process actually was optimising for low cost above all else, then I will of course believe them. But I would be astounded, and would have to rethink a lot of my prior beliefs about railways, given some of the choices made in respect of the current XR 2 route.

 

[SynthD]

Getting around tunnels at Kings Cross and Victoria will force the line to go extremely deep.

I don’t know tunnel depths, but I thought the point of safeguarding was that sufficient space at a sensible depth is assigned to this project. Going another route likely means going deeper than is advisable.

 

[HSTEd]

Just one examl,e - its sounds simple to ‘rebuild Clapham Junction above ground’ - but the cost of that alone would be billions. Then there is the disruption on top. And then there’s the minor point that there’s nowhere to put a portal between Clapham Junction and Victoria.

I remember spending quite a long time looking at the railways in South London with Google Earth whilst doing crayonista doodles.

The number of places where you can put a tunnel portal in South London is really rather restricted, far more than you might expect.
The very high road densities and tendencies of railways to run on viaducts really does a number on that.

I agree that it seems unlikely that two Crossrail scale underground platforms and some tunnel is going to get close to the cost of a giant reconstruction of Clapham Junction - if such a reconstruction is even possible without mass compulsory purchase and demolition.

 

[NorthLondoner]

I'm curious to know if it's feasible to shelve the New Southgate branch assuming upgrades on the Piccadilly Line take place bringing in sufficient demand as well possibly some enhancements to the Great Northern routes.

Though the Great Northern has it's own story to tell.

 

[Sad Sprinter]

I remember spending quite a long time looking at the railways in South London with Google Earth whilst doing crayonista doodles.

The number of places where you can put a tunnel portal in South London is really rather restricted, far more than you might expect.
The very high road densities and tendencies of railways to run on viaducts really does a number on that.

I agree that it seems unlikely that two Crossrail scale underground platforms and some tunnel is going to get close to the cost of a giant reconstruction of Clapham Junction - if such a reconstruction is even possible without mass compulsory purchase and demolition.

Ah yes, the 2010-2013 days of frenzied Crossrail mapping. I spent most of A-Level history sketching out my preferred route for Crossrail Line 9 or whatever. Great times and great discussion on multiple different forums - not least London Recconections which was approaching its glory days at the time.

 

[A S Leib]

I am not convinced we need KXSP either

Wasn't part of the reasoning behind Euston – King's Cross St. Pancras the need for extra capacity to / from HS2?

 

[D365]

In other words, if we can fit in extra tracks next to existing alignments, or in disused alignments, then we should do so unless tunnelling genuinely would be cheaper.

How many ”cross-city” rail projects around Europe and Australia are taking this approach? It’s not cheap to build new infrastructure alongside a working mainline.

For example, Munich is constructing a new pair of tunnels for their ”Second S-Bahn”, even where it parallels the existing alignment between Hauptbahnhof and Laim.

 

[deaglun]

I’m new here so please don’t be mean, but could it not be cheaper to build the stretch from Seven Sisters to Wood Green and Alexandra Palace on the surface? Most of the old palace gates line is just allotments. There are some blocks of flats (two of which I’ve previously lived in). Would have to level shopping city and the flats above too but that’s potentially on the cards anyway.

 

[cle]

Wasn't part of the reasoning behind Euston – King's Cross St. Pancras the need for extra capacity to / from HS2?

Once Leeds/York and then East Midlands Parkway were killed, this is less relevant. Folks will use St P and Kings X as today, and use the tubes, per today. Similar , adjacent complex, but not quite eh same as arriving into HS2 Euston with all the WCML people.

This was for Euston specifically, which now won't carry the whole of the north. KXSP has far more onward options - the SSL and Thameslink, plus a renewed Piccadilly which will be on fire by then, no poor taste jokes intended.

And the OOC / Crossrail 1/3 number, I think is very conservative.

 

[HSTEd]

I’m new here so please don’t be mean, but could it not be cheaper to build the stretch from Seven Sisters to Wood Green and Alexandra Palace on the surface? Most of the old palace gates line is just allotments. There are some blocks of flats (two of which I’ve previously lived in). Would have to level shopping city and the flats above too but that’s potentially on the cards anyway.

Looking at the route you would probably need a lot of demolition to get through to Alexandra Palace on the surface.
A surface station at Alexandra PAlace would also provoke a very disruptive reconstruction of the station which can be avoided if you just tunnel through.

A continuous tunnel also allows the tunnel boring machines to be launched from New Southgate, where there seems to be a lot more room than there would be further into London

 

[Basil Jet]

I'm curious to know if it's feasible to shelve the New Southgate branch assuming upgrades on the Piccadilly Line take place bringing in sufficient demand as well possibly some enhancements to the Great Northern routes.

About 10 years ago, the team said that the main reason to go to New Southgate was to put a depot there. I am surprised that land to build a depot can't be found somewhere between Northumberland Park and Enfield Lock.


I went to a public meeting in Wimbledon about a decade ago in which I suggested that there was no point in demolishing Wimbledon town centre to build new tunnel platforms when there are surface platforms on the fast lines which are never used except during tennis. I suggested that a new straighter mainline could be tunnelled from Clapham Junction to Hersham with optional platforms at Kingston to take all of the fast trains well away from Wimbledon, allowing Crossrail 2 to put twice as many stopping services through Wimbledon without the demolition of a single blade of grass in the Wimbledon area. The previously subdued crowd suddenly became very enthusiastic, but the panel refused to discuss it and just said it's too late to change the plan now.

 

[SynthD]

I don't think that TfL were explicitly optimising for low costs, whereas I am. They might have been optimising for BCR, but that's conceptually very different: if a project costs £45 bn then it will have a BCR > 1 so long as it produces benefits greater than £45 bn. But that doesn't mean the Treasury will be willing to spend £45 bn, whatever the BCR.

In my view, costs are the correct thing to be optimising for. Given the political and institutional environment we're operating in, we won't get anything built unless we can bring construction costs down. We can't just blame "Treasury Brain" for blocking big rail infrastructure projects: yes, the Treasury's rules probably probably should be reformed, but we have to operate in the Britain we actually live in.

That's a shift away from what the industry tells us is the goal, though I do see why you've made the jump. If you hadn't done so, and stuck with BCR, would you alter the route differently?

I suggested that a new straighter mainline could be tunnelled from Clapham Junction to Hersham with optional platforms at Kingston to take all of the fast trains well away from Wimbledon

To repeat the earlier sticking point, where did you put the CLJ portal?

 

[Bald Rick]

I’m new here so please don’t be mean, but could it not be cheaper to build the stretch from Seven Sisters to Wood Green and Alexandra Palace on the surface? Most of the old palace gates line is just allotments. There are some blocks of flats (two of which I’ve previously lived in). Would have to level shopping city and the flats above too but that’s potentially on the cards anyway.

There is nowhere to put a portal at Seven Sisters, and the old Palace Gates line is almost entirely covered with residential property, much of it high density. Property costs alone would be astronoical.

I went to a public meeting in Wimbledon about a decade ago in which I suggested that there was no point in demolishing Wimbledon town centre to build new tunnel platforms when there are surface platforms on the fast lines which are never used except during tennis. I suggested that a new straighter mainline could be tunnelled from Clapham Junction to Hersham with optional platforms at Kingston to take all of the fast trains well away from Wimbledon, allowing Crossrail 2 to put twice as many stopping services through Wimbledon without the demolition of a single blade of grass in the Wimbledon area. The previously subdued crowd suddenly became very enthusiastic, but the panel refused to discuss it and just said it's too late to change the plan now.

That was looked at, because lots of people suggested it. As I said above, there’s no where at Clapham you can build one portal, let alone two. And the existing station couldnt deal with the passenger numbers. And it was also much more expensive, and took much longer. Not a lot going for it, except that the shopping centre wouldnt have to be demolished, but the owners wanted that anyway IIRC.

 

[haltendehand]

A few points, from south to north:

• Where would you put the tunnel portals for Wimbledon fast lines tunnel? Note that the industrial estate where Network Rail Wimbledon DU is is already pencilled in for a reversing siding (https://crossrail2.co.uk/wp-content/uploads/2016/10/Wimbledon.pdf)
• Wimbledon currently has a 4-platform cut and cover station below the existing one pencilled in. At the moment, with present passenger levels, it is already overcrowded at peak times. Putting XR2 on two platforms and dumping many millions additional passengers a year on the current minuscule concourse would be absolute carnage
• To add two tracks Wimbledon - Clapham you'd need to rebuild 10 road bridges completely, take about 200 back gardens, demolish at an absolute minimum around 30 houses (many historic, some listed) and very likely many more for adequately large worksites. You're also rebuilding Earlsfield at viaduct level, demolishing at least quite a few shops, for absolutely no local gain. Politically, this combination of things, in this area, is virtually impossible. The closest example I can find is EWR's proposal to six-track the Midland Main Line through Bedford, which will demolish about 1 short street of houses. That's in Bedford (not Wimbledon...) and is still incredibly controversial and may well not go ahead
• At Clapham Junction, again, adding additional interchange traffic on to an existing narrow platform and on to the interchange corridors is complete madness. I'm not exaggerating when I say that the station will have to be closed more often than it is open. Remember the prospect of additional crowding from a branch of an Underground line (with a fraction of passengers of CR2) was considered so terrifying an idea that a far better BCR for not much more tunnelling was forfeited
• Also at Clapham, the bottom two platforms are not 'rarely used' - there is extensive freight traffic along here, as this is the only connection between the Brighton Main Line and the West London Line (and therefore the West Coast Main Line). Many of these wait around at Clapham for up to 20 minutes, including in peak time, because every single other inch of the existing rail network is so tightly constrained there's nowhere to wait
• So you need an additional two platforms at least at Clapham. You can't put these at ground level because you'd need an additional 2 approach tracks, at least for a while, and the brand new development just east of the southern throat makes this virtually impossible

As for the central section, I completely disagree a new station at Green Park makes any sense. The purpose of the exercise is not to duplicate the Victoria Line exactly. The Victoria Line already exists and is very efficient at what it does. Stations at the Angel (not that it would be possible with your route) or at Dalston makes vastly more sense in opening up opportunities for new journeys and relieving several lines at once (Victoria + Northern, Victoria + Overground). These are nowadays huge attractors and originators of journeys anyway, not any longer backwaters vs the West End.

Equally, duplicating the Victoria Line exactly north of Finsbury Park seems foolish - whilst there is some crowding here, that corridor is already well served by the Victoria Line, so you'd massively overprovide capacity Finsbury Pk - Tottenham Hale. Why build new trackage to achieve very little?

Now for the northern part:

• The portal out of Kings Cross would require demolition of some of Gifford St, but this is very minor. The far bigger issue is that rebuilding the North London Line bridge (and possibly the High Speed tunnel entrance) is going to be exceptionally difficult. You'd also need to build a site compound, probably at the back of Gifford St and accessed through it
• Once you come out of Copenhagen Tunnel to the north, there is not now any space for 6 tracks because of the Holloway flyover there, built in the 70s. You'd have to reorganise Kings Cross entirely (again) if you wanted to demolish that. The alternative is to demolish Cally Road station and the very large block of flats above Tesco Express and rebuild the road bridge over the railway
• It'd be tricky to fit the new tracks behind the large new blocks of flats in Hornsey Street - at an absolute minimum you'd pay out millions for blighting the flats, more likely you'd have to demolish those too
• You'd have to rebuild an underbridge and an overbridge further along
• There is adequate space further along to rearrange the tracks at the current junction of ECML and the Northern City Line, so that's probably doable
• Finsbury Pk station is already very overcrowded and would require a full rebuild. Even then, there's just no way you can fit four additional platform faces + tracks into the complex (I assume you want to fit the flying junction between the two CR2 branches south of Finsbury Pk), especially with the new block of flats just to the west
• Where would you fit the tunnel portal north of Finsbury Park? Would you take some of the park for it? That's likely to be very unpalatable locally and even nationally given the loss of amenity space and trees
• Rebuilding the entire area around Seven Sisters and the junction (complicated by the need for the freight curve on to the GOBLIN there) will be very expensive and difficult
• Further along, you'd again have to demolish two blocks of flats to fit in two further tracks alongside the GOBLIN
• You'd also have to demolish a very significant part of the industrial estate at Tottenham High Cross to fit a flying junction into there
• Where would you fit the platforms at Tottenham Hale?

Generally, the Finsbury Park - Tottenham Hale section is particularly weak - note a tunnel portal on Crossrail cost nearly £200m - that's the price of a new fully underground station. Building two new tunnel portals just to then also demolish lots of buildings and rebuild a lot of railway without any of the benefits of additional connectivity you'd get from running eg via Dalston would be very poor value for money.

 

[Technologist]

In other words, if we institutions of government were competent, we would have Nordic infrastructure costs (or lower-than-Nordic costs, Denmark and Sweden's costs have been inching upwards in the last decade).

Less flippantly, everybody can agree on one thing: TfL have failed to get Crossrail 2 built, largely because it is so expensive. It's as much of a line on a map as my proposal.

Unfortunately this is the only way that we can actually get lots of rail built. There isn't magical path which will achieve high benefits at low costs. The costs need to be addressed directly, not can just railing against the existence of the treasury being a solution.

Treasury has written big cheques for rail projects before and success tends to reinforce success.

The way to do this is to do cost/ organisational innovation on a smaller scale project (e.g. vertically integrate, bring design in house, set up your own modular factory, actually have leeway to shoot for the moon and hit the stars) then scale this up to a low £billions scale project and then go begging for a cross rail 2 amounts of money.

In hindsight the best way to build HS2 would have been to actually build the easiest 2-3 bits of a hypothetical national high speed network first and try out the contracting/engineering approach on those projects.

 

[HSTEd]

- At Clapham Junction, again, adding additional interchange traffic on to an existing narrow platform and on to the interchange corridors is complete madness. I'm not exaggerating when I say that the station will have to be closed more often than it is open. Remember the prospect of additional crowding from a branch of an Underground line (with a fraction of passengers of CR2) was considered so terrifying an idea that a far better BCR for not much more tunnelling was forfeited
- Also at Clapham, the bottom two platforms are not 'rarely used' - there is extensive freight traffic along here, as this is the only connection between the Brighton Main Line and the West London Line (and therefore the West Coast Main Line). Many of these wait around at Clapham for up to 20 minutes, including in peak time, because every single other inch of the existing rail network is so tightly constrained there's nowhere to wait

Crossrail 2 is probably essential if we want to relax the situation enough at Clapham Junction for a proper rebuild, and get us that Northern Line extension.

 

[JonathanH]

Crossrail 2 is probably essential if we want to relax the situation enough at Clapham Junction for a proper rebuild, and get us that Northern Line extension.

Given that Crossrail 2 in any form now seems unlikely to be built in the commuting lifetime of anyone currently working, a Clapham Junction rebuild must be even less likely. The level of technological and other change in that time means what may seem essential now isn't by that time.

I can't see government policy moving towards new build railway projects anytime soon. It is really hard to see it getting onto the agenda for spending priorities for a good while.

 

[Basil Jet]

As I said above, there’s no where at Clapham you can build one portal, let alone two.

I'm sure you're right, but on an aerial photo the east side of Windmill Road / Spencer Park seems to have enough room for a double track mainline portal the size of the Pudding Mill Lane one. The west side past Wandsworth Prison seems to have enough room for the Crossrail 2 double track portal. Temporary flat junctions could access either portal, and be removed (or rarely used) as soon as both tunnels were operational.

 

[Basil Jet]

I'm sure you're right, but on an aerial photo the east side of Windmill Road / Spencer Park seems to have enough room for a double track mainline portal the size of the Pudding Mill Lane one. The west side past Wandsworth Prison seems to have enough room for the Crossrail 2 double track portal. Temporary flat junctions could access either portal, and be removed (or rarely used) as soon as both tunnels were operational.

... should have said "east side past Wandsworth Prison"

 

[MPW]

If the tunnel took the longer distance routes instead of suburban could there be fewer stations? The suburban frequencies could still be enhanced in that case.