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Proposals for the Upgrade of the Sub-surface Lines

By District Dave

with comments and updates added by Tubeprune


District Dave writes:

I am sure that many of you will be aware that there has, in the recent past, been a major restructuring of London Underground recently under the much-heralded ‘Public Private Partnership’ (PPP).  I do not think there is anyone who uses London Underground who would not agree that the system is in need of major financial investment – many of the trains are in need of replacement, signalling systems are outdated and tracks require major renewal.

Much has been written about this and can be found on the web, so I am not going to comment further, other than to say that, in its simplest terms, the idea is that the infrastructure and assets of London Underground have been leased off to private consortia for the next thirty years. It is the responsibility of these consortia to upgrade and renew these assets and provide the means to an improved service to the travelling public. The ‘operational’ side of London Underground – and this effectively means those of us who are actually involved in the ‘provision’ of the service – remains in public ownership. This is really putting the situation at its simplest and, if you are not aware of more details, I would urge you to do some research on the topic.  Start on this site at the FAQs on the PPP page.

There is a wide divergence of opinion as to the rights and wrongs of PPP, but it is now in place and a reality and what follows is an overview of the plans as they affect the Sub-surface lines.  But even though the money is now available, there can be no magic fix – building a whole new railway is in itself a massive undertaking but renewing one whilst keeping it running (as far as possible) at the same time is even more complex.  There can be no overnight quick fix and what I want to try to convey here is the complexity of the whole programme, the timescales that will be involved and what will hopefully be the outcome at the end of it all.

Many of the details that follow in this article are drawn from a document that outlines London Underground’s ‘vision’ for the Sub-surface Lines.  I’ve used this as the basis of this article but I've tried to explain areas which, in the main document, make a number of assumptions and expand into more detail than is, in my opinion, relevant here whilst at the same time trying to avoid internal jargon and ‘corporate speak’.  So this is not simply a copy of the document but my précis, with my own comments and expansions added as I have felt appropriate in its preparation.  Similarly I have not reproduced many of the statistics or any of the graphical commentaries as these are going into too much of the minutiae of the matter.  Some of the matters addressed are also my own interpretation of the content of the document.

Sub-surface Lines

So that you can appreciate correctly the parts of London Underground that are being discussed here I’ll define what makes up the ‘Sub-surface Lines’.  They are comprised of the Metropolitan, District, Hammersmith & City and Circle Lines – in essence all the lines that do not run through ‘deep tube’ tunnels and who operate (currently) the A, C and D Stock trains.  The observant amongst you may notice that there is no mention of the East London Line.  The ELL is not included within the scope of the review, I assume because it is currently the subject of a whole programme of renewal and extension and although, clearly, a Sub-surface line, falls outside the scope of this programme. 

Programme for Peak Service Change

It is generally considered that the service provision on the Subsurface railway (SSR) will change more than on any other line on London Underground as a result of PPP. 

Tubeprune comments that, curiously, the Metronet and London Underground PPP teams refer to the sub surface network as "SSL" or Sub Surface Lines.  MetronetSSL is the official infrastructure company name.  SSR was the old term originally used in the days when it was offered to Railtrack.  They eventually refused it when they realised that they couldn't run the Heathrow Express to the City and operate the existing frequencies as well.  They thought it was like Thameslink.

It is intended that SSR service frequencies will improve and the services will also change from that offered at the present time – probably the most radical change will be that the Circle Line will, effectively, disappear.  The following will outline the phases of the upgrade.

This is interesting, since LU tried to get rid of the Circle in the early 1990s.  One Underground official suggested a "panhandle" service.  It wasn't really a panhandle, more of a crossed loop.  Trains would run from Hammersmith to Whitechapel via Shepherds Bush, Baker Street, Liverpool Street, Tower Hill, S. Kensington, High Street, Baker Street, Liverpool Street and Aldgate East.  They would reverse at Whitechapel and then take the same route back to Hammersmith via Liverpool Street, Edgware Road, S. Kensington, Tower Hill, Liverpool Street, Baker Street and Shepherds Bush.  It was tried on a number of Notting Hill festival days but the conservative elements within LUL effectively killed it.  It need two extra trains to run but it put a turnround time into each Circle trip.  It was also disliked by the crews since each round trip was about 3˝ hours - two of these, with a meal break, would make a complete duty within an 8-hour day.

The Situation Today

As I mentioned above, the SSR is made up of four services but, to put more detail on this, the following list shows the make up of the total service during the ‘peaks’: 

  • The Metropolitan Line utilises 44 A stock trains each having a total capacity of 1,048 passengers.

  • The District Line utilises 67 D Stock trains each having a capacity of 968 plus 10 C Stock trains each having a capacity of 1,014.

  • The Hammersmith & City line utilises 15 C Stock trains The Circle Line utilises 14 C Stock trains.

These provide a total of 150 trains in service in the central area of London providing 28 trains per hour (tph). The total daily kilometrage approaches 62,000 km.

A word of warning on the train capacity figures shown here.   The passenger capacity of a train is calculated by adding the number of passengers who could fit into the standing area to the number of seats.  In the Underground's calculation, they use a figure of 7 passengers per square metre of available standing area.  Now, imagine a square metre and then try to get 7 people, with briefcases and handbags, to stand it it.  No?  Can't imagine it?   Quite right too.  People just won't do it under normal conditions.  It's much more like 4 per square metre. 

Another thing to bear in mind is that the train is not evenly loaded along its full length.  A good example can be seen on the Victoria Line every day, where many of the station exits are at the south end of the platforms and the trains are packed at that end but with room for more at the north end.  

So, any attempt to relate LU's capacity figures with what actually happens on the train needs to be looked at with a serious reality check.  Thus, in the case of the District, the D Stock capacity is really not more than 673 or 70% of the planner's figure, assuming it is equally loaded throughout, which it isn't.

The Proposals to be Implemented by 2011

Through improvements to signalling systems (though not replacement at this stage), many of which are aimed at relieving various locations and areas that, at the moment, cause delays to services, it is intended that the peak services will be increased to 30 tph from the existing 28 tph. It is also intended that the Circle and Hammersmith & City Line services will have been replaced by what is being called a ‘T Cup’ service, the yellow line shown in Fig. 1 below.

T-Cup Service Plan.gif (4439 bytes)
Fig. 1: Diagram showing the proposed "T-Cup" service, in yellow, which will replace the Circle service.

The T-Cup service will run from Hammersmith to Edgware Road via Tower Hill, that is, trains will start at Hammersmith, go via Edgware Road and Liverpool Street round what is currently known as the ‘Outer Rail’ and then, on arrival back at Edgware Road, the trains will reverse and follow the reverse path back to Hammersmith.  The intention is to create a recovery period (i.e. a layover point) in the trip, which the Circle line does not currently have and which causes many of its problems.  At the present time trains operating the Circle Line simply go ‘round and round’, so once running late there is nowhere that lost time can be caught up, unless the controller decides to ‘reform ‘ (renumber) all the trains, thus putting them back on time.

The Hammersmith & City line service between Liverpool Street and Barking will no longer exist.  The H & C service will reverse at Aldgate.  The Metropolitan's Barking service will be covered by extending the Metropolitan Line services beyond Liverpool Street to Barking.

In Tubeprune's view, the new service proposals present a very risky strategy.  First, the number of trains passing though Praed Street Junction will increase from the present 22.5 to 30, in each direction in each hour.  With delays at Edgware Road caused by crew changes, where the allowance is at least 60 seconds for each train stopping, the effect will be to lock up the junction at regular intervals.  It happens now, so what the result will be will be after a 25% increase in the number of trains is anyone's guess.  With new "safety" restrictions on signalling design and higher train speeds, it is likely that eastbound trains will have to be held at Praed Street home signal rather than the station home signal just outside Edgware Road station. This will lose a train berth and further restrict capacity.

In addition, the plan is to reverse 15 trains an hour at Edgware Road (the "T-Cup and Wimbledon services) in two platforms.   With crossover clearance times, each train will get less than 6 minutes standing in the platform.  This will require split second timing and very close supervision, something the Underground doesn't do well at the moment.

The second issue is the plan to extend Metropolitan services to Barking.  This was predicted by Tubeprune and described here.  It was tried before in 1939 and failed then because another flat junction is put into the route of a long service (over an hour in each direction from Watford or Uxbridge) and this will cause delays over the whole of the sub surface network.  Good metro planning requires that services are kept short, not made longer and less manageable.  It will also require the route to Barking to be gauged for A Stock running, since the stock is currently barred east of Aldgate because of infringements at St Marys, Whitechapel, near Bow Road, Barking and Dagenham. 

On top of all this, LU proposes to introduce the T-Cup service in 2009, before any C Stock replacement trains are delivered.   Where they will get the additional 8 trains they require is a mystery because the 8 additional trains ordered from Metronet are 8-car trains ordered for the Barking extension service.  The plan is that all the A Stock will be replaced before the C Stock (after all, it is older) and the signalling immunisation required for the new AC traction drive system is planned on that basis.

New Trains

By this time, the D Stock fleet will have been refurbished to extend their service life and to improve the ‘ambience’ of the type. Delivery will have commenced of a new fleet of trains for the whole of the SSR.   The plan is for the A Stock to be replaced first,

It is intended that there will be a ‘uniform’ stock for all the SSR lines that will offer improved top speed and comfort.  The new stock will also be equipped with Automatic Train Operation (ATO) and Automatic train Protection (ATP) equipment, although signalling will need to be upgraded before these capabilities can be used.  The provision of air-conditioning is also a possibility.

There are two major factors that will need to be taken into account as far as the new trains are concerned: At present the length of the three stocks varies considerably. The A Stock is comprised of 8 cars, each approximately 51ft in length.  The C Stock trains are made up of 6 cars, also approximately 51ft and the D Stock trains comprise 6 cars, each approximately 60ft in length.  The seating configuration of each of the three stocks also differs greatly – the A Stock has a relatively high number of seats, the C Stock relatively few.  The D Stock falls between the two.

It is intended that the first of these factors will be overcome by making all car lengths 51ft (approx.).  Trains for the Metropolitan Line will be 8 cars, as at present.  The trains for the ‘T Cup’ service (C Stock replacement) will be made up of 6 cars – again as at present.  The D Stock replacement will be 7 cars, which will roughly equate to the length of the existing trains.

How the second factor is to be addressed though is less clear. Whether there will be a standard interior layout irrespective of the route on which the train is being operated or perhaps there could be an airliner-style facility to reconfigure the interiors according to the route operated by being able to slot in or out seating as deemed appropriate for the route.  Personally I think this is unlikely, the plans to date seem to suggest a compromise seating arrangement. I am sure this will become clearer once the plans for the trains are more advanced.  (It has been confirmed to Tubeprune that a uniform seating layout is the plan at present).

One matter that is clear though is that each car will have three sets of double doors – a major problem with the D Stock is the single leaf door configuration which are slow to open and close and which result in extended ‘dwell times’ at stations.  By 2011, the total number of trains in service will have risen to 173 and – as implied above – will be a mix of the old and new fleets.  The projection is that the District line will require two more trains, the new ‘T Cup’ service a further five and the Metropolitan Line a further sixteen to allow for the extended service to Barking. (Current stock delivery plans do not quite line up with this).

Proposals to be Implemented by 2014

It is anticipated that, by 2014, further improvements will have allowed a further increase in the number of trains operating between Uxbridge and Barking by 4tph.  This should result in a train frequency on what is today the north part of the Circle Line to 34tph.  By the end of this phase the A and C Stocks will have been withdrawn from service.  If the D Stock is not replaced yet, where will the two extra trains required for the 2011 services described above come from?

It is also expected that the ATO and ATP will be able to be utilised over the parts of the lines solely operated by the new trains. The total number of trains in service is envisaged to be 180 and only new trains would operate on the northern parts of the lines.  This should allow improved running times that should then reduce the number of trains required to be in service by about ten.  At this point and, as implied by the introduction of ATO/ATP, new signalling systems will have been installed and become operational.

It is intended that a new Service Control Centre to be located at Neasden will by now be operational, at least for the Northern services. Ultimately this centre will be the control point for all the SSR lines, meaning that Earls Court, Baker Street and all the existing small signal cabins will be decommissioned.

Tubeprune is told by informed sources that the PPP contract calls for two control centres.  Don't put all your eggs into one basket, seems to be the word here.

Proposals to be Implemented by 2017

The introduction of the final part of the plan will allow an increase of about 4tph between Wimbledon and Barking, increasing the South Circle capacity to 34tph to match that on the Northern Circle.  It also increases the service from the City to Barking to 34tph, which is an increase of 10tph over the situation today.

The control and signalling systems, the track and the fleet will, by now, all have been upgraded.  All sections will now be controlled from Neasden (doubtful) and all trains running under ATO/ATP.   Total trains in service will now be in the region of 180, all new stock.   District Line services will use all the final increase in the number of trains.


At this point I’ll briefly summarise what all this has brought about, in terms of trains in service and the kilometrage achieved. Today the SSR has 150 trains in service, covering 62,000km each day.  At the end of all this there will be 180 trains in service, a 20% increase, covering a total of 73,700km each day, an increase of 18.9%.  So, those are the plans as to what the SSR services will look like at the end of the programme but there are some pretty radical changes proposed.


The question of the refurbishment, upgrading and renewal of stations is outside the terms of reference of this article, but, of course, the changes will have an impact on stations.  It is well known that commitments have been given that there will be improvements to stations and there are several major projects already underway and a number of other projects have been announced.  But many stations have been neglected for many years. 

I assume that there is a similar plan in place for a programme of station refurbishment in the same way that the report around which I base this article.  However, anyone who uses London Underground on a regular basis and particularly during the ‘peaks’ will be only too well aware that many stations are currently extremely congested, to the point that crowd control measures have to be put into effect on more or less a daily basis at some key interchange points and trains instructed to non-stop for safety reasons.  A lack of station capacity could seriously affect the benefits that the improved train service will offer.  Steps are being taken to ensure that station capacity does not detract from the introduction of the train service upgrade.  This will include forecasts for future demand at stations, assessments of where it is anticipated crowding will increase and the effect this will have on journey times and to consider and amend (if necessary) the station decongestion programme that is already in place.  Other day-to-day station activities will need to be re-examined if the upgraded service is to be fully realised.

Staff Management, Deployment & Training

So, what of the people at the ‘sharp end’ of the train service – the Train Operators?  What will the effect of all this be on them?  It appears that there could well be quite a few changes.   But it doesn’t appear to be all bad news.  At the moment there are a total of 906 Train Operators required for the lines making up the SSR – at the end of the whole programme this is expected to have increased to 1,006 as would be suggested by the increased number of trains that the plan envisages actually putting on the railway.  

The statistics apparently show that the effective driving time per running duty has dropped over the last seven years by about 6%.   I presume this loss of efficiency has come about through the reduction in the working week and the time spent not driving when on meal break (this is 30 minutes plus ‘walking time’ but it is not unusual that the time spent off a train could be up to an hour – therefore the excess is considered as ‘lost’ time).   There is also a concern that this could also be affected with the introduction of ‘family friendly rostering’ which is intended to complement LU’s ‘work-life balance’ policy – a matter I may comment on elsewhere at some future time.

Further matters are also being considered.   The introduction of a uniform rolling stock could offer the possibility of greater flexibility of routes covered, subject of course to appropriate road training having been given.  There is also the matter of Train Operator depots.  Currently there are seven on the SSR but it is considered that they are not ideally located in view of the changes outlined above.  The plan at the moment is actually for the number to increase and for there to be some relocation to the various termini – the idea of this being that it would get away from the problems of a train occupying a platform on the ‘running line’ whilst waiting for a crew relief and thus preventing trains behind it running through in the event of a late relief or non-availability of a driver and so on.  Of course, other ‘train and signal related’ grades will be affected too – and during the implementation there will be implications as far as training staff in new equipment too.

In conclusion, I emphasise that all that I’ve outlined is very much that – it’s been written from a blueprint, which I’m sure will be amended and fine tuned as time progresses but I hope that it has been of interest and at least gives an idea of how the future of the SSR at least is expected to evolve.  As, when and if further news, changes or amendments come to hand, I will try to keep this up to date as far as possible. 

Further reading is available from Metronet.  Images on the Metronet site give an impression of the interior and exterior views of the proposed new rolling stock.   These trains will be built by Bombardier.  The interior view suggests that the trains will have ‘walk through’ cars, whether this proves to be a reality or not only time will tell.  There are clearly advantages to this configuration but, in the light of the need to make trains up in different lengths dependant on route, can this be achieved whilst retaining flexibility?  Yes, if you plug in your laptop after reforming the train in the depot so that you can tell it how long it is and make the ATP will work properly.

For more information go to District Dave's website.


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