Future crossrails in London?

[tasky]

Thameslink, Crossrail, and Crossrail 2 all take a similar approach of connecting up two suburban lines on opposite sides of London that would run into termini, and linking them through a tunnel with some intermediate stations.

So for Crossrail that's the slow GWML lines that would have terminated into Paddington, and the Essex lines into Liverpool Street; I believe Thameslink more or less connected London Bridge trains with Great Northern/MML; Crossrail 2 would take some Waterloo suburban services from the SWML and connect them to the West Anglia mainline.

Are there any other crossrails that would make sense? Is there a case for linking up lines that run into Charing Cross or Marylebone? Taking some services from Victoria to somewhere?

The three drivers for this kind of project seem to be that it's easier than creating new terminal capacity in central London, also provides useful connections for suburban commuters, while at the same time creating effectively a new intra-urban express tube line while it's in the city.

What other crossrails might be a good idea?

 

[JonathanH]

What other crossrails might be a good idea?

It really doesn't matter - there is zero chance of Crossrail 2 being built let alone any future ones.

 

[swt_passenger]

There was a thread early last year to discuss proposals for a Crossrail 3:
https://www.railforums.co.uk/threads/where-would-you-like-to-see-crossrail-3-go.160483/
All a bit early really, as JonathanH just pointed out.

 

[ijmad]

It really doesn't matter - there is zero chance of Crossrail 2 being built let alone any future ones.

I'm not sure I'd say zero. Low for the moment, but in better times the idea is bound to come around again. London will likely need the capacity before 2050. Besides, this is a speculative ideas forum.

My thoughts:

TfL's prediction of peak time loadings in 2040 show there are still capacity issues East-West during the peaks. The Jubilee Line and Crossrail's Abbey Wood branch are both at capacity. 12tph on the eastern Crossrail branches may look inadequate very quickly.

So I like to imagine a scheme where the full 24tph from the current Crossrail core goes to Abbey Wood and beyond (Dartford, Ebbsfleet, Gravesend as planned, maybe more) while the Shenfield branch is connected to a second core through London. Call it Crossrail 1X.

• A good place to site the interchange between 'Crossrail 1' and 'Crossrail 1X' would be under Limehouse. This could be redeveloped in to a larger interchange for passengers coming off LTSR services.
• The route could then follow the river. Stops might include Cannon Street (with Bank interchange too?), a stop near the old Aldwych station (perhaps using its entrance for lift access), Charing Cross (re-using the old Jubilee line infrastructure), Victoria (for CR2).
• Then let's give West London some much needed love, by having it take over the Wimbledon branch of the District Line (which featured in many old CR2 plans and is forecast to be near capacity soon enough). Maybe some trains could also go to Clapham Junction via the West London Line.

You could do with 8 carriage trains here to avoid costly platform extensions for the ex-District Line section. 8 carriages x 24tph is far more capacity than 9 x 16tph which is what the Shenfield branch will get for now, and slightly more than 11 x 16tph if Crossrail ever goes max length.

The freed up capacity on the District Line could bring considerable opportunities. You'd have 24tph from the city coming out of Earls Court, sending 12tph to Richmond / Ealing Broadway would be a solid capacity increase. The current 8tph Wimbleware service could be diverted to Kensington Olympia.

 

[MidlandMainlie]

Wasn't there some talk of linking Crossrail to the WCML slows in the Old Oak Common area to divert services away from Euston for HS2. Seems to have died a death unfortunately.

 

[kevin_roche]

Wasn't there some talk of linking Crossrail to the WCML slows in the Old Oak Common area to divert services away from Euston for HS2. Seems to have died a death unfortunately.

Originally there was a plan to run trains to Milton Keynes.

From wikipedia.

Network Rail's July 2011 London & South East Route Utilisation Strategy (RUS) recommended that a short railway line could be built to connect the West Coast Main Line (WCML) with the Crossrail route. This would enable train services that currently run between Milton Keynes Central and London Euston to be re-routed via Old Oak Common to serve central London, Shenfield and Abbey Wood.
The report argued that this would free up capacity at Euston for the planned High Speed 2, reduce London Underground congestion at Euston, make better use of Crossrail's capacity west of Paddington, and improve access to Heathrow Airport from the north.[152] Under this scheme, all Crossrail trains would continue west of Paddington, instead of some of them terminating there. They would serve Heathrow Airport (10 tph), stations to Maidenhead and Reading (6 tph), and stations to Milton Keynes Central (8 tph).[153]

In August 2014, a statement by transport secretary Patrick McLoughlin indicated that the government was actively evaluating the extension of Crossrail as far as Tring, with potential Crossrail stops at Wembley Central, Harrow & Wealdstone, Bushey, Watford Junction, Kings Langley, Apsley, Hemel Hempstead and Berkhamsted. The extension would relieve some pressure from London Underground and London Euston station while also increasing connectivity. Conditions to the extension were that any extra services should not affect the planned service pattern for confirmed routes, as well as affordability.[154][155] This proposal was shelved in August 2016 due to "poor overall value for money to the taxpayer".[156]

I suspect that may get resurrected if HS2 get Cancelled or delayed. A relief for congestion on trains from Milton Keynes might be welcomed by those who use them.

 

[Terry Tait]

Linking the GEML to Southeastern by means of a tunnel from London Liverpool Street to London Bridge would be very welcome for the journeys I make which are usually Staplehurst to Southend or Bishops Stortford.

 

[JonathanH]

Wasn't there some talk of linking Crossrail to the WCML slows in the Old Oak Common area to divert services away from Euston for HS2. Seems to have died a death unfortunately.

I suspect that may get resurrected if HS2 get Cancelled or delayed. A relief for congestion on trains from Milton Keynes might be welcomed by those who use them.

The problem with the WCML isn't Euston though, is it. So using Crossrail for WCML services doesn't help with running more trains to Milton Keynes, especially given the rolling stock used which isn't as long as 240m and isn't suited to longer journeys.

 

[ijmad]

The problem with the WCML isn't Euston though, is it. So using Crossrail for WCML services doesn't help with running more trains to Milton Keynes, especially given the rolling stock used which isn't as long as 240m and isn't suited to longer journeys.

I seem to recall it being suggested purely as a possible way to take pressure off Euston when they thought there was going to be a major station rebuild (along with the new HS2 platforms) because this would shut various groups of platforms for a while.

 

[swt_passenger]

I seem to recall it being suggested purely as a possible way to take pressure off Euston when they thought there was going to be a major station rebuild (along with the new HS2 platforms) because this would shut various groups of platforms for a while.

Yes, IIRC it provided little or no additional services on the WCML slows, it just moved some existing services onto Crossrail.

It wouldn’t be an “additional Crossrail” either, in the context of the current thread...

 

[ijmad]

The LTSR seems like a strong candidate for cross-London services. Not only does it provide useful express services from many parts of the easternmost edges of London itself, its current peak frequency of 21tph in to Fenchurch Street is a good core frequency for a Crossrail (plus a few), and a lot of its services operate in a very metro-like way already. Plus Fenchurch Street is a weird terminal station and could do with shutting in favour of something better connected to the tube.

CR1 is relieving Paddington and Liverpool Street, and CR2 will relieve Waterloo. Thameslink was a game changer for Kings Cross and London Bridge and has had some impact on travel patterns in to Charing Cross and Cannon Street. HS2 will bring big changes to Euston.

What terminal remains that (a) is poorly connected to the rest of London's transport infrastructure, (b) is in need of modernisation, and (c) has growing customer demand and (d) could provide useful relief to other tube lines.

Perhaps the answer is Marylebone?

The corridor suggested for Horizon DLR extension (Bank, City Thameslink, Holborn) might be a good start and then perhaps Warren Street and Baker Street to create further interchange opportunities before joining the existing line.

Metropolitan Line services would be diverted to just Uxbridge and Watford (ideally Watford Junction!), the new Crossrail line fully taking over the westernmost pair of tracks north of Harrow-on-the-Hill, and providing services for Amersham (and the Chesham branch) before going on to Aylesbury. Extra Uxbridge trains allow all Piccadilly Line services to terminate at Rayners Lane all day, segregating the tube lines and allowing trackbed adjustments to end compromise height platforms and provide level access.

On the Chiltern Main Line, we'll take over service to Oxford (why not, it's not much further than Reading?) and Aylesbury via Princes Risborough. Track will be shared with longer distance services still in/out of Marylebone initially, but possibly diverted to a simple two-platform terminus at Old Oak Common.

 

[Mag_seven]

It really doesn't matter - there is zero chance of Crossrail 2 being built let alone any future ones.

Indeed they will look at Crossrail 1 and think, "once bitten, twice shy".

 

[tranzitjim]

How easy would it be to merge the Sub-Surface lines with the non-underground network such as the Overground network?

Can you fit a full sized Overground train through the sub-surface tunnels?

Should a plan be done, to replace, or enlarge the deep-tube tunnels with full sized tunnels. That would increase the capacity of those lines somewhat.

 

[Flinn Reed]

Suggestion for a Crossrail 3 route - as with other suggestions I would utilise the Metropolitan Line, being unusual as a tube line by going quite far out of Greater London, as well as having semi-fast/fast services in the peaks.

I would divert Met line services via a new tunnel north of Finchley Road, but keeping an interchange at Marylebone/Baker Street at new platforms. If possible, some Chiltern stopping services could divert into the Met Line platforms at Baker Street, improving capacity at Marylebone for longer distance services.

The next stop could be Tottenham Court Road, creating a major hub interchange between the three crossrail routes. Then either Blackfriars or City Thameslink for interchange with ThamesLink, as well as serving the west part of the City. Then a combined new interchange of Fenchurch Street / Tower Hill / Tower Gateway - this would improve connectivity to Fenchurch Street and relieve the Central/Circle/District lines to/from the City.

The tunnel would then go south of the river, serve a new station around new developments at New Bermondsey, with interchange to the Overground, then emerge out of ground with the lines out of London Bridge - taking over a selection of Southern and/or Southeastern metro services, relieving pressure around London Bridge.

I would also use this as an opportunity to rationalise and simplify the remaining sub-surface lines. The District line can be seen as confusing, but is not as easy to split as the Northern line as some Wimbledon services continue via Victoria. Also, the Circle Line is a useful connection around central London, but the frequency is relatively low for journeys where only the circle can be used.

My suggestion would be to have 3 lines, all with a service pattern of around 12tph - this combination would maintain similar frequencies along all sections of the existing subsurface routes. The Circle Line would run as now, from Hammersmith and around the city, but terminating at High Street Kensington, using two of the four platforms there**. Removes the confusion around the Circle Line at Paddington and Edgware Road.

The District Line would run from Upminster, through central London and Earl's Court, with most trains terminating at Richmond. With the Piccadilly set to take over the Ealing branch, the Richmond branch would gain an increased frequency, with some trains terminating early (maybe somewhere around Turnham Green).

A third line would replace the H&C line, running as the proposed 'Wimbleware' from Wimbledon to Edgware Road, then continuing to Barking via Kings Cross and Liverpool Street.

** I would withdraw the Olympia shuttle, in favour of passengers changing for the Overground at West Brompton. The shuttle is infrequent anyway, and can be quite underused.

 

[MarlowDonkey]

Can you fit a full sized Overground train through the sub-surface tunnels?
.

The A60/A62 stock was reputedly the highest and widest of any stock in Great Britain. So anywhere they could go, Overground trains could too.

 

[JKF]

The problem with taking over underground lines would be the huge disruption while they were converted. Central ones carry a huge number of passengers and wouldn’t be easily accommodated elsewhere.

 

[Bald Rick]

The key problem with any of this is finding sufficient space underground for stations. You need a 300 metre long, 50 metre wide (nearly) straight (nearly) level area with no major obstructions, that can’t be more than about 50 metres deep. And it needs two separate links to the surface, one at each end, that can safely accommodate the number of people expected to use it - and these links also need to be clear of any major obstructions.

Finally it needs to be able to be joined to the next station, which meets the same criteria, by a tunnel with a reasonable alignment that is also free of any major obstructions.

You won’t find anywhere in the Liverpool St / Bank / Moorgate area, nor near Tottenham Court Road, that meets this requirement.

 

[PeterC]

Its fun to get the crayon box out, I do it often enough myself, but really you first need to decide what the objective is and stick to it. If you don't you end up with daft results like metro trains without toilets running all the way to Reading.

 

[JonathanH]

If you don't you end up with daft results like metro trains without toilets running all the way to Reading.

Which isn't a problem because there are other options for passengers at that end of the line.

 

[PeterC]

Which isn't a problem because there are other options for passengers at that end of the line.

Did I not make my point clear or are you just ignoring it for the sake of a snide response?

 

[HSTEd]

The key problem with any of this is finding sufficient space underground for stations. You need a 300 metre long, 50 metre wide (nearly) straight (nearly) level area with no major obstructions, that can’t be more than about 50 metres deep. And it needs two separate links to the surface, one at each end, that can safely accommodate the number of people expected to use it - and these links also need to be clear of any major obstructions.

I am not convinced that the depth requirement is a particularly onerous one now.
The primary volume in a traditional underground station is the access tunnels and the concourse and things like that.
With the development of technologies like ThyssenKrupp's "MULTI", it will allow a considerably more cross-section efficient access to deep tunnels.

The example of Barcelona's Line 9 does also demonstrate the possibility of putting all of the station infrastructure inside the tubular bore that contains both tracks, which also provides a lot of ventilation space and the potential for escape walkways in both directions from the station.

Either way, whilst there is no room for "conventional" stations in central london, with sufficient money I would not rule out simply going deeper.
The Moscow Metro has stations as deep as 84 metres after all.

 

[JonathanH]

Did I not make my point clear or are you just ignoring it for the sake of a snide response?

No. I was just expressing my opinion that
a) I don't see the use of 345s on services to Reading as being daft
b) there are other options for travellers beyond Maidenhead if they need to use a toilet
c) there are other options to travel on a train with different seats.

345s terminating at Maidenhead and a shuttle train from Maidenhead to Didcot would have been a much worse idea than running 345s through to Reading.

 

[Bald Rick]

I am not convinced that the depth requirement is a particularly onerous one now.
The primary volume in a traditional underground station is the access tunnels and the concourse and things like that.
With the development of technologies like ThyssenKrupp's "MULTI", it will allow a considerably more cross-section efficient access to deep tunnels.

The example of Barcelona's Line 9 does also demonstrate the possibility of putting all of the station infrastructure inside the tubular bore that contains both tracks, which also provides a lot of ventilation space and the potential for escape walkways in both directions from the station.

Either way, whilst there is no room for "conventional" stations in central london, with sufficient money I would not rule out simply going deeper.
The Moscow Metro has stations as deep as 84 metres after all.

Sorry but that’s just not right. We are talking very high capacity railways, with stations that need vertical capacity of over 500 people a minute each way. No lift system can do that, to that depth, within a reasonable footprint. Even Willy Wonka would struggle.

Barcelona Line 9 has rather less than half the capacity of a Crossrail, and has no stations with anywhere near the likely usage of a station in the City of London.

Railways must be designed for the number of passengers that use are expected to use them, and that includes station circulation space, vertical access, emergency acces and other factors.

 

[The Ham]

Sorry but that’s just not right. We are talking very high capacity railways, with stations that need vertical capacity of over 500 people a minute each way. No lift system can do that, to that depth, within a reasonable footprint. Even Willy Wonka would struggle.

Barcelona Line 9 has rather less than half the capacity of a Crossrail, and has no stations with anywhere near the likely usage of a station in the City of London.

Railways must be designed for the number of passengers that use are expected to use them, and that includes station circulation space, vertical access, emergency acces and other factors.

You could probably increase lift capacity of you had lifts that could share shafts.

As an example if you had an up shaft and a down shaft you could have more than 2 lifts in that space, so you could have a lift loading at the bottom, a lift going up, a lift unloading at the top, a lift loading at the top a lift going down and a lift unloading at the bottom. (If you had through loading/unloading you could even have it that pairs of lifts traveled together with the first in the pair doing the over movement before opening the doors and the second doing it after closing the doors, that would be 8 lifts in 2 shafts).

Depending on the length of the trip up/down you could even have more lifts.

That's assuming an up and over then back down again loop type design, if you went more complex you could have an up and down shafts with left/right "platforms" for the lifts to pull into which would limit the risk of loading/unloading issues backing the system up. Assuming 2 lifts traveling up and 2 down with 4 at the top and 4 at the bottom (lift platforms configured in a LW or LWJ shape with the shafts to the lower points of th W) that's 10 or more lifts in two shafts, yes you'd need more space but only at the top/bottom and only by spreading it out along a platform or a ticket hall.

At the out end of the LW or LWJ you would have a setup like this with it repeating for the number of lift platforms that you have so as to allow through loading/unloading:

. . . . P. . . . L. . . . A. . . T. . . . F. . . . O. . . . R. . . M.
Loading [ ] unloading [ ] loading [ ] unloading
. . . . . . . . \ . . . . . . . . . . | . . . . . . . ./
. . . . . . . . ==================
. . . . . . . . . . [ Up ] . . . [Down]

Depending on "ground level" space you could have a pair of shafts for each platform (assuming platforms outside of the tracks) with a crossover route between the platforms (either up or down) to allow for double backing and maintenance/failure of one set of lifts.

P.S. I'm not Willy Winker, but using his glass elevator concept which can move in many ways it isn't that difficult to increase the moving capacity of a pair of shafts beyond that which a pair of lifts can carry.

 

[Bald Rick]

You could probably increase lift capacity of you had lifts that could share shafts.

As an example if you had an up shaft and a down shaft you could have more than 2 lifts in that space, so you could have a lift loading at the bottom, a lift going up, a lift unloading at the top, a lift loading at the top a lift going down and a lift unloading at the bottom. (If you had through loading/unloading you could even have it that pairs of lifts traveled together with the first in the pair doing the over movement before opening the doors and the second doing it after closing the doors, that would be 8 lifts in 2 shafts).

Depending on the length of the trip up/down you could even have more lifts.

That's assuming an up and over then back down again loop type design, if you went more complex you could have an up and down shafts with left/right "platforms" for the lifts to pull into which would limit the risk of loading/unloading issues backing the system up. Assuming 2 lifts traveling up and 2 down with 4 at the top and 4 at the bottom (lift platforms configured in a LW or LWJ shape with the shafts to the lower points of th W) that's 10 or more lifts in two shafts, yes you'd need more space but only at the top/bottom and only by spreading it out along a platform or a ticket hall.

At the out end of the LW or LWJ you would have a setup like this with it repeating for the number of lift platforms that you have so as to allow through loading/unloading:

. . . . P. . . . L. . . . A. . . T. . . . F. . . . O. . . . R. . . M.
Loading [ ] unloading [ ] loading [ ] unloading
. . . . . . . . \ . . . . . . . . . . | . . . . . . . ./
. . . . . . . . ==================
. . . . . . . . . . [ Up ] . . . [Down]

Depending on "ground level" space you could have a pair of shafts for each platform (assuming platforms outside of the tracks) with a crossover route between the platforms (either up or down) to allow for double backing and maintenance/failure of one set of lifts.

P.S. I'm not Willy Winker, but using his glass elevator concept which can move in many ways it isn't that difficult to increase the moving capacity of a pair of shafts beyond that which a pair of lifts can carry.

I understand all this, but even with all that, how long does it take to load / unload at each end? Using ski lift technology as a comparator, the largest detachable gondolas are the size of a very large lift, have large wide openings for the doors, and take about 20-30 seconds to load / unload (including door opening / closing), overlapping the loading / unloading with the next one simultaneously whilst moving slowly. They go off at a headway of around 30 seconds. The very best of these manages under 6000 people an hour each way. If a lift system could match that (which I very much doubt), then a central London Crossrail station would need at least 5 of them. And that would be an awful lot of space required at ground level, let alone the tunnelling necessary to do it.

 

[HSTEd]

Sorry but that’s just not right. We are talking very high capacity railways, with stations that need vertical capacity of over 500 people a minute each way. No lift system can do that, to that depth, within a reasonable footprint. Even Willy Wonka would struggle.

Except this is not traditional 19th Century lift system.
A MULTI system can provide vehicles cycling every 15s per shaft pair, since they use linear motors do vehicles go up one side and down the other.

We will have two pairs of shafts for each platform, so four in total at the least. That is sixteen lifts up and down per hour.

So to reach your target you only need 30 people in each lift, which is actually a reasonable number.
And since its. 200m platform at least 3 pairs is reasonable so we can meet your service spec with a lift out of service.

Deep station access is one of the primary roles invisaged by ThyssenKrupp.
It isn't a lift as we would understand it, its a very high capacity vertical APM.

Barcelona Line 9 has rather less than half the capacity of a Crossrail, and has no stations with anywhere near the likely usage of a station in the City of London.

Railways must be designed for the number of passengers that use are expected to use them, and that includes station circulation space, vertical access, emergency acces and other factors.

And the relatively puny 12m TBM is rather far from the state of the art now. We can have 15-18m bores now.

Which means we can have even larger platforms, and escape routes you could drive an ambulance down.

Big bore TBMs will change the world

 

[Bald Rick]

Except this is not traditional 19th Century lift system.
A MULTI system can provide vehicles cycling every 15s per shaft pair, since they use linear motors do vehicles go up one side and down the other.

We will have two pairs of shafts for each platform, so four in total at the least. That is sixteen lifts up and down per hour.

So to reach your target you only need 30 people in each lift, which is actually a reasonable number.
And since its. 200m platform at least 3 pairs is reasonable so we can meet your service spec with a lift out of service.

Deep station access is one of the primary roles invisaged by ThyssenKrupp.
It isn't a lift as we would understand it, its a very high capacity vertical APM.


And the relatively puny 12m TBM is rather far from the state of the art now. We can have 15-18m bores now.

Which means we can have even larger platforms, and escape routes you could drive an ambulance down.

Big bore TBMs will change the world

As I said, I understand all of that.

A 15 second cycle time for, say, 30 people a ‘cabin’ simply isn’t practical (doors open, load up, doors warning, doors close, ‘cabin’ moves clear, next cabin moves into place). Allowing for doors being held, slow boarders (not everyone can speedwalk into a lift), it would be nearer 30 seconds, which is what Thyssen quote for larger systems, and is consistent with the tube lift systems today, ie time from lift arriving to lift departing.

That means you need 8-9 lift shafts up, and the same down. Plus a maintenance spare pair. Plus emergency stairs. Plus separate fire access. That is a phenomenal amount of volume between the surface and the platforms where there can’t be anything ‘immovable’ in the way. And a lot, lot more digging than ‘normal’ Crossrail stations. Of course it would be possible, but it would be likely to be impractical. Non starter.

 

[The Ham]

As I said, I understand all of that.

A 15 second cycle time for, say, 30 people a ‘cabin’ simply isn’t practical (doors open, load up, doors warning, doors close, ‘cabin’ moves clear, next cabin moves into place). Allowing for doors being held, slow boarders (not everyone can speedwalk into a lift), it would be nearer 30 seconds, which is what Thyssen quote for larger systems, and is consistent with the tube lift systems today, ie time from lift arriving to lift departing.

That means you need 8-9 lift shafts up, and the same down. Plus a maintenance spare pair. Plus emergency stairs. Plus separate fire access. That is a phenomenal amount of volume between the surface and the platforms where there can’t be anything ‘immovable’ in the way. And a lot, lot more digging than ‘normal’ Crossrail stations. Of course it would be possible, but it would be likely to be impractical. Non starter.

I'm still not sure that you are understanding the sort of system which is being talked about, this video should help:

By being able to move the cars sideways you aren't limited by the loading/unloading times.

In fact you could have a car which is stopped indefinitely and it only have a fairly small impact on the capacity of the system.

It means that you could have lift cars going up one shaft with the gap between them down to the time needed to move the car ahead out of the way. Which would also be the time needed to move it into place in the shafts behind the car ahead.

 

[HSTEd]

As I said, I understand all of that.

A 15 second cycle time for, say, 30 people a ‘cabin’ simply isn’t practical (doors open, load up, doors warning, doors close, ‘cabin’ moves clear, next cabin moves into place). Allowing for doors being held, slow boarders (not everyone can speedwalk into a lift), it would be nearer 30 seconds, which is what Thyssen quote for larger systems, and is consistent with the tube lift systems today, ie time from lift arriving to lift departing

That means you need 8-9 lift shafts up, and the same down.

It is possible for each shaft pair to have more than one vehicle loading/unloading at each end at once though.
For example an I shaped system would have two vehicels loading or unloading at each end at once, with the cabins moving off to the sides of the lift shaft pairs before opening their doors.
It won't get to double the speed but it will certainly be much faster than a single system.

So probably 5-6.

Plus a maintenance spare pair. Plus emergency stairs. Plus separate fire access. That is a phenomenal amount of volume between the surface and the platforms where there can’t be anything ‘immovable’ in the way. And a lot, lot more digging than ‘normal’ Crossrail stations. Of course it would be possible, but it would be likely to be impractical. Non starter.

I question the utility of an emergency staircase for a deep level tube station.
People climbing 25 stories to escape (50m or more) is going to be extremely slow, and that is without assuming people abandoning bags on the stairs as they begin to tire or panic and people simply giving up the climb half way up because they are too old/unfit/whatever to make it to the top. In the world trade centre attacks progress rates of 0.2m/s have been estimated, and that was in the descent.


The easiest way to provide a seperate fire access and a redundant escape route would proabbly be to bore an adjacent service tunnel and use that to allow the fire brigade or emergency services to rapidly reach the incident, whilst also allowing for redundant escape routes from the station.
The cost of providing the LFB with two new stations near the ends of the service bore is likely to be negligible compared to the cost of the rest of the scheme.

Combined with diverse back up supplies for the lifts in the stations (battery banks from different manufacturers most likely, as well as taps from local DNO supplies and the traction supplies) it seems likely the best option is to simply evacuate to adjacent stations through the main and service tunnels.

1500m or so to the adjacent stations might seem a long way, but given that it is near, or totally, flat I think the usable throughput is likely to be higher than anything you can achieve with staircase escape routes.
Especially as trains/service vehicles can be used to assist the evacuation.

 

[The Ham]

If space at ground level was an issue you could always have lifts to an existing lower level of an existing station (which would aid with transfers between services and then use the existing/upgraded routes to ground level.

Such upgraded routes may require the use of adjacent retail units (which often flank tube stations).

However it does lead to the question, could it be better to have fewer stations along such a deep line? In that if it's going to take (say) up to 5 minutes from ground level to departure on the next train and then a few more minutes back up again then the time saving over walking 1.5km is going to be fairly small.

Given that few are likely to be on the outer edges of the line and being able to get exactly where they want to on the tube network anyway, what's the likely penalty for changing to get to a station between two of the Crossrail X stations?

Especially given that it would mean that overall many journey times would be faster by not needing to stop at quite so many stations.

As an example a North South line calling at

Waterloo
China Town (about 0.3 miles from, and between, Leicester Square and Tottenham Court Road)
Euston

For those going short distances they would just use the existing services whilst those going longer distances would benefit from the faster journeys until they switched to the existing network.

With the above example you could have a 500m moving walkway to link to the two nearby stations. You could even consider a link to Covent Garden & Soho.

In doing so you could be within 5 minutes of quite a large area in an area which isn't traditionally well served by the tube network. You also put Soho and China Town on the tube map.

By having those walkways you reduce the capacity constraints at the main access point as the passenger loads are more spread out.