Could Double Deck trains be viable in the UK?

[Bletchleyite]

you say that DD trains can only improve capacity by 40%, but if a line is at absolute saturation as regards tph physically able to use the line then surely putting DD's on and INCREASING capacity by 40% should be welcomed...

A UK DD would be too narrow for 3+2 seating, regular UK rolling stock is only just wide enough for it and a DD would be narrower. If you have a simple 64 seat TSO (2+2 throughout) and made that 3+2, that's a 25% uplift already (80 seats). You can easily squash in a few more rows by using thin seat backs to get the other 15%. So it's much easier to get your 40% uplift by other means.

Buses are different in that because a DD bus doesn't have to be any narrower than a SD bus, you come very close to doubling seated capacity by adding an upstairs.

Though I do think it's poor the way we give scant or no consideration to loading and unloading times on buses in the UK, which leads to the single door layout which is hopelessly impractical for busy routes unless they are of the very traditional non-cross-city "suburbs to bus station" kind where the door is effectively only being used in one direction at any given time.

 

[Teflon Lettuce]

A UK DD would be too narrow for 3+2 seating, regular UK rolling stock is only just wide enough for it and a DD would be narrower. If you have a simple 64 seat TSO (2+2 throughout) and made that 3+2, that's a 25% uplift already. You can easily squash in a few more rows by using thin seat backs to get the other 15%. So it's much easier to get your 40% uplift by other means.

yes, but as can be seen from the Thameslink thread where thinner, more upright seats have been introduced, this "uplift" in capacity is going down like a lead balloon... as it did when buses turned to this idea when it was used to counteract the drop in capacity caused by DDA..
In any case, if you increase the capacity of an sd without adding in more doors then it slows down boarding and alighting, due to a greater number of passengers per door...
Also on many of the lines that are at saturation point already {especially in the south east} already operate with 3+2 stock so that option isn't available in any case.... so that leaves 2 options open... either double the number of decks or double the number of tracks... now as I asked in my previous post... knowing the land prices in London and the South East, and knowing that a lot of land would have to be purchased at a premium due to things already being built on that land... which would be cheaper?

The truth is that all the evidence that DD's wouldn't work in the UK is based on one flawed, poorly executed experiment.

 

[JonasB]

It's not about running more trains, the task is to carry more passengers. As this discussion has largely demonstrated, double deck trains may hold more passengers per train but normal passenger behaviour negotiating narrow stairs, queueing to get on or off and turning up on the platform in larger numbers means that the higher capacity trains cannot run as frequently as well engineered single deck trains which have a slightly lower capacity per train, (i.e. a double deck train will only give about 40% more capacity than a single deck).
As for your assertion that running double deck trains is cheaper than extending platforms, that is only true if the line structure gauge will allow passage of those trains. In the UK, it would mean rebuilding most overbridges, and many underbridges, moving every platform away from the running rails and as for tunnels! Despite the need for some stations to be modified or even rebuilt, longer platforms is nowhere near as expensive unless you only consider running double deck trains across the Fens and the Somerset levels.

I interpreted the original question as why double deckers are seen as a solution in other countries, but english is not my native language.

It has been discussed here after an order for new double deck local trains was placed. And it seems like a good idea, they can only run two trains per hour in each direction, there are a lot of other trains on the line. And they can't run longer trains without extending the platforms, which would cost more and take a lot longer. And double deck trains is no problems on the Swedish loading gauge.

 

[Dr Hoo]

The thing is, if you design a double deck train with WIDE stairways and WIDE doors... add in a one-way flow through the carriage... and even add platform on BOTH sides of each track... then the DD train will load/ unload as fast, if not faster, than an SD train... as has been amply proved with buses the speed of boarding/ alighting has nothing to do with whether a vehicle is sd or dd but more to do with how many doors, position of doors and width of doors... in fact, as has been proved with buses an all seated DD will have dwell times shorter than a standee sd with the same number of passengers... due to the passengers wishing to board/ alight NOT having to fight their way past standees...

you say that DD trains can only improve capacity by 40%, but if a line is at absolute saturation as regards tph physically able to use the line then surely putting DD's on and INCREASING capacity by 40% should be welcomed...

out of interest... IF a line needs more capacity what is more expensive... converting the line to DD with the existing number of tracks? or doubling the number of tracks? Considering land prices in the places where this is likely to be needed then I'm guessing DD is the way forward...
but then again that would just be too "continental" for us Brits!

I suggest that you think about a typical British route that superficially might be a candidate for DD - say Victoria to places in the South London suburbs. I am being kind as there are no electric wires to raise. To get the benefits of optimised ‘wide’ trains you need to cut all the platforms back significantly, which then leaves the problem of ‘residual’ ordinary trains. Many stations have canopies that would also have to go and there are many overbridges crammed with cables and pipes that often already have unsatisfactory highway geometry (and station buildings in some cases). The newly narrowed platforms have, at the same time, to be enhanced to accommodate much greater surges of passengers heading for exits, subways and footbridges. Think of places like Tulse Hill and Norwood Junction. Some significant widening of the railway corridor would be necessary in some cases, even for the same number of tracks.
Many under bridges have girders that could not accommodate the new wider rolling stock, so would also need complete rebuilding. Besides the cost the works would cause massive disruption and couldn’t all be done at the same time anyway.
I am not a betting man but your “guess” might just turn out to be wrong.

 

[Teflon Lettuce]

I suggest that you think about a typical British route that superficially might be a candidate for DD - say Victoria to places in the South London suburbs. I am being kind as there are no electric wires to raise. To get the benefits of optimised ‘wide’ trains you need to cut all the platforms back significantly, which then leaves the problem of ‘residual’ ordinary trains. Many stations have canopies that would also have to go and there are many overbridges crammed with cables and pipes that often already have unsatisfactory highway geometry (and station buildings in some cases). The newly narrowed platforms have, at the same time, to be enhanced to accommodate much greater surges of passengers heading for exits, subways and footbridges. Think of places like Tulse Hill and Norwood Junction. Some significant widening of the railway corridor would be necessary in some cases, even for the same number of tracks.
Many under bridges have girders that could not accommodate the new wider rolling stock, so would also need complete rebuilding. Besides the cost the works would cause massive disruption and couldn’t all be done at the same time anyway.
I am not a betting man but your “guess” might just turn out to be wrong.

But, by the same measure, if the number of tracks between any 2 points are at saturation point... to the point where the only other option would be to add extra tracks then what would the cost of THAT be? what is the current cost of land in London per acre? then of course there are all the thousands of homes that would need to be compulsory purchased {at a premium price} Can you imagine the outcry if, in some of the "posher" parts of London and the south east it was announced "we're doubling the tracks... it's the only way forward... we're gonna demolish x thousand homes to do it"?

No, it wouldn't get through would it? so what other options are left? Rail apartheid by putting the fares up so high that demand is restricted only to the super rich whilst everyone else slums it on commuter coaches? I think it's going to be a situation soon in many parts of the commuter network of "double deck" or "strangle".... then again I suppose we could instead build new lines underground... but how much does THAT cost per mile?

 

[Dr Hoo]

But, by the same measure, if the number of tracks between any 2 points are at saturation point... to the point where the only other option would be to add extra tracks then what would the cost of THAT be? what is the current cost of land in London per acre? then of course there are all the thousands of homes that would need to be compulsory purchased {at a premium price} Can you imagine the outcry if, in some of the "posher" parts of London and the south east it was announced "we're doubling the tracks... it's the only way forward... we're gonna demolish x thousand homes to do it"?

No, it wouldn't get through would it? so what other options are left? Rail apartheid by putting the fares up so high that demand is restricted only to the super rich whilst everyone else slums it on commuter coaches? I think it's going to be a situation soon in many parts of the commuter network of "double deck" or "strangle".... then again I suppose we could instead build new lines underground... but how much does THAT cost per mile?

At least the underground lines (or other capacity contributors such as the DLR) have *relatively* little disruption to the conventional network. They also provide the chance to reconfigure the network towards current travel patterns, e.g. Docklands, airports, high speed links, and away from historic constraints such as the Thames, the array of peripheral termini and minimal heavy rail in ‘The City’.
Simply having trains with 40% more passengers suddenly alighting at Victoria would hardly be ‘solving’ the capacity challenge.

 

[Teflon Lettuce]

At least the underground lines (or other capacity contributors such as the DLR) have *relatively* little disruption to the conventional network. They also provide the chance to reconfigure the network towards current travel patterns, e.g. Docklands, airports, high speed links, and away from historic constraints such as the Thames, the array of peripheral termini and minimal heavy rail in ‘The City’.
Simply having trains with 40% more passengers suddenly alighting at Victoria would hardly be ‘solving’ the capacity challenge.

no, admittedly using DD trains to solve a capacity issue does have the danger of just moving the capacity bottleneck further down the line... but, to a layman, it seems that DD trains are just dismissed out of hand as "just not the British way of doing things"
As I've asked a number of times... what are the differences in cost/ mile between doubling existing routes, Double decking those routes and building entirely new routes underground...

The fact that I still haven't been given even a vague answer to the question means that DD trains have been dismissed out of hand by the powers that be without even so much as a feasibility study... let alone a costing study... having been done!

 

[swt_passenger]

no, admittedly using DD trains to solve a capacity issue does have the danger of just moving the capacity bottleneck further down the line... but, to a layman, it seems that DD trains are just dismissed out of hand as "just not the British way of doing things"
As I've asked a number of times... what are the differences in cost/ mile between doubling existing routes, Double decking those routes and building entirely new routes underground...

The fact that I still haven't been given even a vague answer to the question means that DD trains have been dismissed out of hand by the powers that be without even so much as a feasibility study... let alone a costing study... having been done!

Have you read the report I linked to?

 

[Teflon Lettuce]

Have you read the report I linked to?

I have to admit, no due to time pressures... however you cited a cost of £1 billion to DD London- Brighton... how much would it cost to add another 2 tracks beside the existing trackbed? or 2 build a totally new alignment between London and Brighton... I think both would cost a lot more than £1 billion....

 

[Dr Hoo]

I have to admit, no due to time pressures... however you cited a cost of £1 billion to DD London- Brighton... how much would it cost to add another 2 tracks beside the existing trackbed? or 2 build a totally new alignment between London and Brighton... I think both would cost a lot more than £1 billion....

One last try:
It isn’t simply about increasing the capacity of existing corridors, at least in cities. (Things like four tracking the Trent Valley were about speed differentiation rather than capacity per train.)
If you think about new rail development around London in the last 50 or so years it has mainly about creating new corridors.
Victoria Line - interchanges and new Thames tunnel
Jubilee Line - interchanges, Docklands and four new Thames crossings
HS1 - speed differentiation, interchange at King’s Cross and new Thames Tunnel
Overground orbital - interchanges and effectively two new high-capacity Thames crossings
Thameslink - spreading loads across multiple ‘terminals’, interchange and far more effective Thames crossing
DLR - Docklands, interchanges and two new Thames crossings
Heathrow Airport - new heavy rail and underground tunnels (not surface links) to new traffic objective
Crossrail - spreading loads across multiple terminals, direct services, Docklands and Heathrow plus yet another Thames crossing
Emirates Airline - Docklands and new Thames Crossing

Seems to be a bit of a pattern emerging?

 

[Teflon Lettuce]

One last try:
It isn’t simply about increasing the capacity of existing corridors, at least in cities. (Things like four tracking the Trent Valley were about speed differentiation rather than capacity per train.)
If you think about new rail development around London in the last 50 or so years it has mainly about creating new corridors.
Victoria Line - interchanges and new Thames tunnel
Jubilee Line - interchanges, Docklands and four new Thames crossings
HS1 - speed differentiation, interchange at King’s Cross and new Thames Tunnel
Overground orbital - interchanges and effectively two new high-capacity Thames crossings
Thameslink - spreading loads across multiple ‘terminals’, interchange and far more effective Thames crossing
DLR - Docklands, interchanges and two new Thames crossings
Heathrow Airport - new heavy rail and underground tunnels (not surface links) to new traffic objective
Crossrail - spreading loads across multiple terminals, direct services, Docklands and Heathrow plus yet another Thames crossing
Emirates Airline - Docklands and new Thames Crossing

Seems to be a bit of a pattern emerging?

none of the examples you've quoted are anything to do with what I am asking about though, are they? they are all about creating NEW links.. what I am talking about is where a line is full to capacity between 2 defined points... say Brighton and Victoria... it then becomes a choice between 3 options...
1. Increasing the number of tracks between those 2 points
2. Creating a totally new link which, in these days of "environment sensitivity" will involve many miles of tunnel {see HS2 debate on this matter}
3. Double decking the trains

As I've REPEATEDLY said... because of the prohibitively high land prices in London and South East option 1 would probably be prohibitively expensive. Ditto option 2... with the added expense of all those miles and miles of tunnelling to factor in...

Are you really telling me that, given those FACTS that spending limited amounts of money to allow Double Deck trains on existing pathways would be MORE expensive than option 1 or 2?

 

[swt_passenger]

I have to admit, no due to time pressures... however you cited a cost of £1 billion to DD London- Brighton... how much would it cost to add another 2 tracks beside the existing trackbed? or 2 build a totally new alignment between London and Brighton... I think both would cost a lot more than £1 billion....

Personally I have no idea what anything might or might not cost. But you seem to think no one has ever thought of this before. I think some of NR’s more recent route studies also discuss the pros and cons.

 

[Peter Mugridge]

To get the benefits of optimised ‘wide’ trains you need to cut all the platforms back significantly, which then leaves the problem of ‘residual’ ordinary trains.

That bit could be solved by fitting retractable platform edges, but that would carry with it the very clear problem that it's more mechanical things to go wrong.

The newly narrowed platforms have, at the same time, to be enhanced to accommodate much greater surges of passengers heading for exits, subways and footbridges. Think of places like Tulse Hill and Norwood Junction. Some significant widening of the railway corridor would be necessary in some cases, even for the same number of tracks.

Very true, and the widening wouldn't just be to ensure the platforms can cope with the passenger volume; it's not just the platform edges that need to be trimmed back to allow proper double deck stock width at full depth, but the track centers may well need moving further apart at some locations. As an example - a class 444 is 2.80m wide; a Z20500 is 2.846m wide. Not a huge difference, but probably enough to cause the kinematic envelopes to clash in more than a few locations.

 

[Dr Hoo]

none of the examples you've quoted are anything to do with what I am asking about though, are they? they are all about creating NEW links.. what I am talking about is where a line is full to capacity between 2 defined points... say Brighton and Victoria... it then becomes a choice between 3 options...
1. Increasing the number of tracks between those 2 points
2. Creating a totally new link which, in these days of "environment sensitivity" will involve many miles of tunnel {see HS2 debate on this matter}
3. Double decking the trains

As I've REPEATEDLY said... because of the prohibitively high land prices in London and South East option 1 would probably be prohibitively expensive. Ditto option 2... with the added expense of all those miles and miles of tunnelling to factor in...

Are you really telling me that, given those FACTS that spending limited amounts of money to allow Double Deck trains on existing pathways would be MORE expensive than option 1 or 2?

I am not aware that simply moving a lot more people between Brighton station and Victoria station has ever been identified as a distinct problem requiring an isolated solution.
I am, however, aware that along the route many more people have wanted to access Gatwick Airport from places such as London Bridge, Blackfriars, City Thameslink, Farringdon, King’s Cross, Kensington Olympia, Reading, Guildford, etc.
I am also aware that a growing number of people travel into East Croydon where the station already suffers from narrow crowded platforms that don’t need to be made any narrower and have 40% more people thrown at them. I am aware that two more platforms are needed to allow faster acceptance of trains (as at London Bridge) but there wouldn’t be room for these if the existing platforms had to be made wider. A pressing need at Croydon was for better passenger distribution - hence Tramlink.
DD is a classic example of a simplistic solution looking for a simple problem. It has nothing to offer to complex problems such as those found in the South East of England.

 

[Teflon Lettuce]

I am not aware that simply moving a lot more people between Brighton station and Victoria station has ever been identified as a distinct problem requiring an isolated solution.

Good grief... did I say there was?!? I just picked those 2 places as an example!

I am, however, aware that along the route many more people have wanted to access Gatwick Airport from places such as London Bridge, Blackfriars, City Thameslink, Farringdon, King’s Cross, Kensington Olympia, Reading, Guildford, etc.

None of which, as far as I am aware are on the route between Victoria and Brighton.. therefore isn't an argument against using DD's as a solution to the hypothetical question I asked!

I am also aware that a growing number of people travel into East Croydon where the station already suffers from narrow crowded platforms that don’t need to be made any narrower and have 40% more people thrown at them. I am aware that two more platforms are needed to allow faster acceptance of trains (as at London Bridge) but there wouldn’t be room for these if the existing platforms had to be made wider. A pressing need at Croydon was for better passenger distribution - hence Tramlink.

Of course, I would expect the costings for DD conversion to include any remodelling of stations needed to make DD's viable!

DD is a classic example of a simplistic solution looking for a simple problem. It has nothing to offer to complex problems such as those found in the South East of England.

As opposed to the "we don't do DD in Britain, so DD operation is a total non-starter so we won't even cost it" stance that you take... it's quite obvious from your replies that, even if converting a line to DD operation was cheaper than any other solution at a factor of 1:100 you would still say that it isn't an option...

I've also noted that you still haven't provided a single FACT about the relative costs... which is the question I keep asking....

 

[Dr Hoo]

As a non-engineer I am the wrong person for you to ask about project costs.
However, after a 40-year career in the rail industry, involved in various ways with many projects I did learn not to waste precious technical resources on development of schemes for which there was no clear rationale.

If you can identify a point-to-point corridor where there is a straightforward choice between more conventional trains needing additional tracks over a material distance and the same number of optimised DD trains fitting existing track capacity (albeit accompanied by major station modifications as well as tunnel enlargement, replacing OHLE, etc.) where there is no obvious case for linking with other schemes, traffic developments and so forth I am sure that some other members of this well-endowed forum might be able to hazard a guess at some costings.
But first you need to name your line.

 

[Shaw S Hunter]

Perhaps members might like to read this webarchive.nationalarchives.gov.uk/+/http:/www.dft.gov.uk/about/strategy/whitepapers/whitepapercm7176/railwhitepapersupportingdocs/provevalddtrains.pdf, a Network Rail report from way back in 2007 but commissioned by the DfT. It considered at least some of the issues being discussed here, in particular the options and costs of even longer trains or possible double-decking. One of the case studies was even London-Brighton!

The double-deck options were for nothing more ambitious then GB or GC gauges. GB would restrict lower deck seating to 2+1 with upper deck at 2+2. GC would be one seat wider on each deck. These were compared to having 16-car trains. Essentially GC DD appeared the most expensive option. But which came out cheapest depended on the route suggesting that in some situations GB DD was at least worth considering. However the report did not consider the additional track options. Anyone looking at this report for costings should of course bear in mind its age.

 

[Teflon Lettuce]

Perhaps members might like to read this webarchive.nationalarchives.gov.uk/+/http:/www.dft.gov.uk/about/strategy/whitepapers/whitepapercm7176/railwhitepapersupportingdocs/provevalddtrains.pdf, a Network Rail report from way back in 2007 but commissioned by the DfT. It considered at least some of the issues being discussed here, in particular the options and costs of even longer trains or possible double-decking. One of the case studies was even London-Brighton!

The double-deck options were for nothing more ambitious then GB or GC gauges. GB would restrict lower deck seating to 2+1 with upper deck at 2+2. GC would be one seat wider on each deck. These were compared to having 16-car trains. Essentially GC DD appeared the most expensive option. But which came out cheapest depended on the route suggesting that in some situations GB DD was at least worth considering. However the report did not consider the additional track options. Anyone looking at this report for costings should of course bear in mind its age.

only had a chance to take a quick glance at the moment... but table 1.1 makes for interesting reading... it seems to point to the answer to my question... that the case for DD operation is, much like everything else in public transport, a case of "horses for courses"... sometimes it will give the best value for money, other times it will be a poor investment... Compare the figures for options London- Brighton and London- Colchester...

which brings me back to the original reason why I posed the question of DD operation... why is there a blanket "no" to such operation in this country? after all I thought Government rules stipulate that the best value for money should ALWAYS be sought... if there's a policy to not even consider DD operation on any given route project then how can Network Rail be so certain that it is delivering best value for the billions of pounds of taxpayer's money it spends?

 

[swt_passenger]

Perhaps members might like to read this webarchive.nationalarchives.gov.uk/+/http:/www.dft.gov.uk/about/strategy/whitepapers/whitepapercm7176/railwhitepapersupportingdocs/provevalddtrains.pdf, a Network Rail report from way back in 2007 but commissioned by the DfT. It considered at least some of the issues being discussed here, in particular the options and costs of even longer trains or possible double-decking. One of the case studies was even London-Brighton!

The double-deck options were for nothing more ambitious then GB or GC gauges. GB would restrict lower deck seating to 2+1 with upper deck at 2+2. GC would be one seat wider on each deck. These were compared to having 16-car trains. Essentially GC DD appeared the most expensive option. But which came out cheapest depended on the route suggesting that in some situations GB DD was at least worth considering. However the report did not consider the additional track options. Anyone looking at this report for costings should of course bear in mind its age.

I did post that link already, back on page 1 - post #9. The main proponent of DD here subsequently said he hadn’t read it a few days later - posts #68/69.

I’m out.

 

[pdeaves]

(I have only skimmed this thread, so I apologise if this point has already come up).

One way to get faster access/egress to double deck trains would be to have double deck platforms. That could also be used for crowd control if not all stations have an upstairs platform. Upper deck for A, B, D and F; lower deck for A, B, C, D, E and F. If you rebuild stations in this way, you would put platform edge doors to obviate the new fall risk.

Clearly the trains themselves would still need stairs inside for emergencies.

 

[NSEFAN]

only had a chance to take a quick glance at the moment... but table 1.1 makes for interesting reading... it seems to point to the answer to my question... that the case for DD operation is, much like everything else in public transport, a case of "horses for courses"... sometimes it will give the best value for money, other times it will be a poor investment... Compare the figures for options London- Brighton and London- Colchester...

which brings me back to the original reason why I posed the question of DD operation... why is there a blanket "no" to such operation in this country? after all I thought Government rules stipulate that the best value for money should ALWAYS be sought... if there's a policy to not even consider DD operation on any given route project then how can Network Rail be so certain that it is delivering best value for the billions of pounds of taxpayer's money it spends?

It's not so much a case of a blanket ban on DD stock, more that in most cases there's so much legacy infrastructure that it's almost never going to be good value for money trying to resolve that. Combine this with the need to then also manage extra passengers at the terminus stations, and also the high risk involved in upgrading an operational railway, it starts to become more sensible to just build new lines (hence Crossrail 1 and beyond).

 

[Teflon Lettuce]

It's not so much a case of a blanket ban on DD stock, more that in most cases there's so much legacy infrastructure that it's almost never going to be good value for money trying to resolve that. Combine this with the need to then also manage extra passengers at the terminus stations, it starts to become more sensible to just build new lines (hence Crossrail 1 and beyond).

but if you look at table 1.1 in the link above you will see that in one case study it shows that conversion to DD operation DOES give best value for money, even with the neccessary works to make it possible... and surely the £1-2 billion it would cost to do a conversion is MUCH better value for money than the MULTIPLE BILLIONS it costs for a totally new line?

 

[Clip]

but if you look at table 1.1 in the link above you will see that in one case study it shows that conversion to DD operation DOES give best value for money, even with the neccessary works to make it possible... and surely the £1-2 billion it would cost to do a conversion is MUCH better value for money than the MULTIPLE BILLIONS it costs for a totally new line?

You are fighting a good fight here but your use of caps is impressive.

However - I see what you are saying about the costs but people along the line you chose in your hypothetical would have to lose their homes and the railway would encroach on to other homes which are currently blocked from the railway by the first row and thus a lot of unhappy people and I really wouldn't like the chaos that would ensure at Clapham Junction for these works either as it would also have a knock on effect to the SWR lines too I would imagine and for the length of time the work would take to upgrade would certainly not make the venture worthwhile

 

[NSEFAN]

but if you look at table 1.1 in the link above you will see that in one case study it shows that conversion to DD operation DOES give best value for money, even with the neccessary works to make it possible... and surely the £1-2 billion it would cost to do a conversion is MUCH better value for money than the MULTIPLE BILLIONS it costs for a totally new line?

If the numbers in that table include all the relevant costs, then yes it would be better value, although only because the existing trains are already 12 car and full. In the longer term, if growth continues then a new line will eventually be needed anyway, but then predicting the longer term is quite difficult (unless we can build triple decker trains? )

There is also a political dimension to this. The disruption caused by such an upgrade may not be politcally acceptable, even though logic says its the best value way forward. I don't think GTR or AGA passengers could stomach additional closures, given the severe problems faced over the past few years.

 

[Teflon Lettuce]

If the numbers in that table include all the relevant costs, then yes it would be better value, although only because the existing trains are already 12 car and full. In the longer term, if growth continues then a new line will eventually be needed anyway, but then predicting the longer term is quite difficult (unless we can build triple decker trains? )

There is also a political dimension to this. The disruption caused by such an upgrade may not be politcally acceptable, even though logic says its the best value way forward. I don't think GTR or AGA passengers could stomach additional closures, given the severe problems faced over the past few years.

Thing is, the more I look at the report then the less it looks like a feasibility study... more a "let's work out all the arguments against" study... seems to me that the person{s} tasked with writing it were trying their hardest to justify their already set opinion... and not approach the subject with an open mind.

 

[Shaw S Hunter]

Thing is, the more I look at the report then the less it looks like a feasibility study... more a "let's work out all the arguments against" study... seems to me that the person{s} tasked with writing it were trying their hardest to justify their already set opinion... and not approach the subject with an open mind.

Whether or not that is true there is the historical tendency of the DfT to simply say "that's too difficult" in response to various issues. And the politicians have been equally guilty. There were certainly times when BR was effectively instructed to introduce inflation-busting fare rises as a way of choking off demand to avoid dealing with capacity issues. More recently it's clear that a policy of "let them stand" holds sway. Overcrowding is not unique to this country but the extent to which it is officially tolerated, or even encouraged, is much greater than in most other countries.

Coming back to the report it made no attempt to weigh up the costs of building new tracks/routes nor to assess the long-term impact of the severe disruption arising from enabling double-decking. I would suggest that the experience of WCRM is still sufficiently fresh in the memory that similar large-scale rebuilding exercises will remain off the table for many years to come.

 

[Teflon Lettuce]

You are fighting a good fight here but your use of caps is impressive.

However - I see what you are saying about the costs but people along the line you chose in your hypothetical would have to lose their homes and the railway would encroach on to other homes which are currently blocked from the railway by the first row and thus a lot of unhappy people and I really wouldn't like the chaos that would ensure at Clapham Junction for these works either as it would also have a knock on effect to the SWR lines too I would imagine and for the length of time the work would take to upgrade would certainly not make the venture worthwhile

I'm not sure what you mean.. why would a conversion to DD mean knocking down homes? IF you increase the number of tracks or create a totally new route then you have to do so, but DD's operating on existing number of tracks don't use up any extra land..

 

[Peter Mugridge]

I'm not sure what you mean.. why would a conversion to DD mean knocking down homes? IF you increase the number of tracks or create a totally new route then you have to do so, but DD's operating on existing number of tracks don't use up any extra land..

The below quote from an earlier post of mine might be what he's thinking of - in most places with just two tracks, or even four, the extra width required wouldn't be that much, but where there are a large number of tracks and there are homes very close to the existing boundary fence, it is quite possible that the formation may need widening enough to result in demolition on one side of the line. It's not just the extra 5cm or so width of the train, that's 10cm extra per pair of tracks and that's direct width, not taking into account any additional kinematic envelope allowances, so in practice you'd probably need an extra 20cm width per pair of tracks. Multiply that by the number of tracks in the vicinity of the major termini and junctions and you're very easily looking at needing width equal to an extra track. In some locations that's going to put the side of a train within touching distance of some of the closer properties.

it's not just the platform edges that need to be trimmed back to allow proper double deck stock width at full depth, but the track centers may well need moving further apart at some locations. As an example - a class 444 is 2.80m wide; a Z20500 is 2.846m wide. Not a huge difference, but probably enough to cause the kinematic envelopes to clash in more than a few locations.

 

[Teflon Lettuce]

The below quote from an earlier post of mine might be what he's thinking of - in most places with just two tracks, or even four, the extra width required wouldn't be that much, but where there are a large number of tracks and there are homes very close to the existing boundary fence, it is quite possible that the formation may need widening enough to result in demolition on one side of the line. It's not just the extra 5cm or so width of the train, that's 10cm extra per pair of tracks and that's direct width, not taking into account any additional kinematic envelope allowances, so in practice you'd probably need an extra 20cm width per pair of tracks. Multiply that by the number of tracks in the vicinity of the major termini and junctions and you're very easily looking at needing width equal to an extra track. In some locations that's going to put the side of a train within touching distance of some of the closer properties.

it's still a lot less land than either increasing the number of tracks or building a totally new line though isn't it? And I took his argument to be that going for DD would lead to too much disruption/ land grab to be acceptable to the local residents

 

[Peter Mugridge]

it's still a lot less land than either increasing the number of tracks or building a totally new line though isn't it? And I took his argument to be that going for DD would lead to too much disruption/ land grab to be acceptable to the local residents

I'd say that's true because unless you went for tidal flow you'd need a minimum of two extra tracks for any conventional widening wouldn't you?