Longer trains on the Northern line?

[rtt1928]

I was unsure where to put this and know that it may move, depending upon whether the mods/admins consider it has been opened in the wrong thread.

I was wondering whether the 1995 stock lends itself to 7 or 8 car operation and whether the Northern line platforms could accommodate 7 or 8 car 1995 stock trains as a way of increasing capacity on the NL in order to reduce overcrowding at the busiest periods of the day.

I am of course thinking of when the Jubilee line 1996 stock trains were lengthened to 7 cars and am wondering if something similar can be done for the Northern line. I am also aware that money (or the lack of) is the major constraint on what can be done.

[ducatisti]

they already stick over the ends at some platforms (Moorgate being the one that springs to mind), and I think they are on the limit for a lot more.
Unless you went back to the days of 9-car 38 stock and some cars only opening at certain stations, you'd not be able to. Well, maybe as and when walk-through stock is developed.

[i3lu]

Only deep level station fitted for 8 cars its Highgate. There are some platforms where are not enough 6 cars and they cut first/last set of doors, so the first/last carriage will be completely out of station. In my opinion, the trains for NLE must have access between carriages like S7/8 and it will be the best way for increasing capacity.

[Deleted]

TfL has no plans for extending the length of the 95 Stock (or at least there weren't 3 months ago). As has been said the platforms aren't long enough and extending them would be even more difficult than the work that was done on the circle line for S stock.

The trains for NLE/NLU2 will be very structurally similar to the existing fleet.

[North End]

Jan 23, 2017 13:30:33 GMT rtt1928 said:

I was unsure where to put this and know that it may move, depending upon whether the mods/admins consider it has been opened in the wrong thread.

I was wondering whether the 1995 stock lends itself to 7 or 8 car operation and whether the Northern line platforms could accommodate 7 or 8 car 1995 stock trains as a way of increasing capacity on the NL in order to reduce overcrowding at the busiest periods of the day.

I am of course thinking of when the Jubilee line 1996 stock trains were lengthened to 7 cars and am wondering if something similar can be done for the Northern line. I am also aware that money (or the lack of) is the major constraint on what can be done.

Absolutely no chance. The 95 stock was designed to fit inside the existing platforms, and they're already a tight fit in many locations. You simply couldn't add a car to the 95 stock as you would end up with the equivalent of one car in the tunnel at virtually every tunnel platform, plus slightly more in a few places. Plus there would be issues with siding berths in many locations.

Whilst shorter than a 59/72 stock train, remember that there were numerous locations where these trains stopped with either the cab in the tunnel or the rear doors in the tunnel, with cutting out being done by the motorman or guard as necessary. The only way Northern Line trains would be lengthened is if the 95 stock is replaced with a new design, pushing the length out to the maximum extent deemed possible. Returning to the length of a 59/72 stock train would introduce some challenges at many locations, although it probably could be done - albeit at some cost.

I should add the caveat that this all assumes no one in the future decides to carry out a programme of lengthening at almost every tunnel platform. Never say never, but the cost and disruption would be so enormous I don't think it's something LU has even contemplated to any serious extent.

With hindsight it's very fortunate the Jubilee Line was able to take 7 cars of 96 stock without major modification. Swiss Cottage and St. John's Wood could very easily have been built for 7 cars of 1938 stock, to match the rest of the Bakerloo Line, and the Baker Street to Charing Cross section may then have been built to match.

[philthetube]

59 stock used to stop with the front cab in the tunnel virtually everywhere, as this appears not to be allowed on a DOO train there is no chance of returning to 59 stock length.

[North End]

Jan 24, 2017 0:07:48 GMT philthetube said:

59 stock used to stop with the front cab in the tunnel virtually everywhere, as this appears not to be allowed on a DOO train there is no chance of returning to 59 stock length.

It does, sort of, happen on the S stock. Whether a Tube tunnel would be regarded as more unacceptable I don't know. Are there any places where S stock cuts out leading doors that the T/Op physically can't leave their cab via the side door?

[philthetube]

none I can think of, everywhere is wide enough to be able to climb out through the side cab doors. I can't think of any location, at or away from stations where you cannot climb out, even the tunnels north of Bakes street are wide enough.

[melikepie]

What are the platform constraints?

[North End]

Jan 24, 2017 1:34:40 GMT melikepie said:

What are the platform constraints?

Simply the fact that virtually every tunnel platform on the line would have to be extended by approximately 20 metres if you're to provide a length equivalent to the Jubilee Line. Bear in mind that you'll have to do this whilst keeping the railway running as far as possible, comply with all modern health & safety standards, and fit in your work around all the other tunnels that might be near to the platform ends. Also remember that there are normally gradients on the approach to and departure from platforms, in some cases with short sections which are very steep in railway terms, that would need to be dealt with somehow. Never say it'll never happen, but you're talking about *serious* money. Then when you've done this, you've got to fit a 400ft train in places like Tooting Broadway siding, which simply isn't going to happen without yet more tunneling work. Every stabling berth needs to be looked at, and I can more or less guarantee that a lot of places would need major work - places like High Barnet Sidings are already tight for space. This is before we make all the changes to the signalling etc.

[crusty54]

and the trains wouldn't fit in the depots

[Dstock7080]

Jan 24, 2017 0:38:07 GMT North End said:

Are there any places where S stock cuts out leading doors that the T/Op physically can't leave their cab via the side door?

Yes, there are stations where the driver cannot access the platform directly, J door and passenger doors required.

[alpinejohn]

This earlier thread may provide an insight as to how the pre war 9 car service operated a limited stopping service on the Northern Line with some cars cut out of service at the many shorter central area platforms.

districtdavesforum.co.uk/thread/12197/9-car-platforms

As others have said, never say never, as tunneling technology continues to develop dramatically allowing projects which would be far to difficult/costly to now be accomplished. Tunnelling straight under the Alps was for many years considered a pipe-dream and now its is reality.

The short answer is that if you just need to enhance the capacity of a railway, you look at the cheapest/easiest solutions first, moving only to implement more expensive solutions when those options have been exhausted. In terms of passenger carrying capacity, things like updating the signalling to allow more trains per hour has essentially the same effect as extending trains, hence TFL are rather keen to spend on signalling improvements. A similar theme underlies the idea of separating the CX/Bank services to effectively remove the bottle neck area delays where trains are routinely stalled waiting for their route to clear. Whilst separating the service may be less convenient for passengers, it should allow far better flow and greater throughput.

I suspect that the immense cost and disruption of extending all platforms to accommodate longer trains would be right at the very bottom of the list of options. Indeed I suspect that some limited dualling of central area platforms could be a better solution before ever going in that direction. Doubtless someone at TFL has carefully studied dwell times at most if not all central area stations to see if extended dwell times at a single station - such as Tottenham Court Road was causing massive delays to service on the whole of the rest of the line. If so there just might be a case for dualling the platforms (4 instead of 2) as this could be largely done without impact on day to day operations. Then by allowing following trains to effectively overlap at a bottleneck station, the problem of extended passenger dwell time will be largely removed. I suspect that dualling a couple of central stations would be a whole lot cheaper than modifying most if not all of them.

[Chris M]

There is also the potential option of adding a second platform to the opposite side of the train to separate alighting and boarding flows. Not cheap by any stretch of the imagination, but probably cheaper than a second running tunnel as well.

[Ben]

One of the issues on the SSR and the Pic was that OPO required drivers to be able to see CCTV monitors which were placed on platform ends. With in-cab CCTV that restriction is less important, so trains can once again stop with the front and rear portions of the outer cars in tunnel. If a safety case could be made for this on deep level lines, then you could start considering adding an extra car, with only the innermost door being on the platforms. But stabling would still be an issue, signalling berths would need to be assessed, possibly pointwork moved too. Then fleet mods to introduce the new car and more flexible SDO. Big money even without platform re-boring. I suppose though that at some point it'll become desirable. Its a pity that the fairly recently rebuilt platforms at London Bridge, Angel, Bank, dont make any passive provision.

[crusty54]

Jan 24, 2017 10:55:20 GMT Chris M said:

There is also the potential option of adding a second platform to the opposite side of the train to separate alighting and boarding flows. Not cheap by any stretch of the imagination, but probably cheaper than a second running tunnel as well.

The problem with this is that the majority of Northern line stations in Central London have platforms either side of central stairs. You would still have to excavate massive amounts of material and fit in (step free) access to any new platforms.

By far the better way is to split the Northern branches and with the Battersea extension a more intensive service could be provided.

[Chris M]

Indeed, but you would need to excavate approximately this amount of earth for platforms in new running tunnels, but you wouldn't have to excavate the running tunnels and step-plate junctions either side of the station as well.
I did say it would not be cheap, and I probably should said it would not be easy either (but neither would be the second running tunnel option). Yes, the best option in the medium term is splitting the branches (it's not feasible until after Camden is expanded, which is still a few years away from starting let alone finishing), but now is the time to start the outline planning for long-term upgrade options so that they can be delivered in 10 years when the demand forecasts indicate they will be needed in 10-15 years rather than delivered in 15 years when the forecasts say they will be needed in 1-2 (which is the best that's been achieved recently) or 5 years ago (as has more common).
What I mean is that you assess each station and find out what the approximate costs of schemes X, Y and Z each delivering a different increase in capacity, what side benefits they will bring, and what is required to deliver them. That way when the time comes to upgrade you can very quickly dust off the plans and assess the contemporary benefit-cost ratio and then start work on whichever is adjudged best, rather than having to start from scratch at that point.
Veering off-topic slightly but I believe that when the project to extend the DLR stations to three cars was assessing the stations, they also looked at what would be required to extend them to four cars. For example at Mudchute they extended the platforms northwards for three cars and (I guess) will have decided that the same option would be best if/when extending to four, and they will know that such will require track realingment for platform 3 and thus probably reprofiling of the embankment. Even if no detailed design work was done they don't need to spend time examining a southwards extension.

[alpinejohn]

The idea of longer trains is probably not going to fly given other cheaper ways to increase capacity.

I am however perplexed by the perceived "difficulty" at segregating the Northern branches at Camden Town. I think the existing tunnel configuration already allows this? If tomorrow the decision was made to split the routes then I suspect that all that is needed is to set the relevant points and eventually plain line them at a time when it is not in use. I am not aware of any stretch of track which both routes must use if the proposed split configuration was implemented even if the Northbound platform approaches get very, very close to each other.

Inherently the "Camden Town" problem seems entirely down to managing passenger volumes in a limited space. Currently there is one often grossly crowded central link passage between northbound platforms with a similar set up southbound. Add in people actually entering or leaving the station and the lurkers clogging the link corridor waiting by the Next train indicators and voila the central cross link appears to be the core problem.

OK a few "in the know" passengers know about and already use the poorly signed link passage at the south end of the platforms. Inherently the answer surely is to get on now and create additional large capacity links between the two north and southbound platforms which with suitable signage should handle most of the route interchange flows, and free up the central passage mostly for entry/exit. I recognise that TFL also want to make the site fully accessible, but given the local largely NIMBY perspective to planning permission applications for almost any surface level changes that dream seems a very long way off. However it would be rather difficult to find grounds to reject an application by TFL today to create additional inter platform passageways located so far below ground that few if any surface properties can hear the existing trains.

[crusty54]

Feb 9, 2017 11:25:52 GMT alpinejohn said:

The idea of longer trains is probably not going to fly given other cheaper ways to increase capacity.

I am however perplexed by the perceived "difficulty" at segregating the Northern branches at Camden Town. I think the existing tunnel configuration already allows this? If tomorrow the decision was made to split the routes then I suspect that all that is needed is to set the relevant points and eventually plain line them at a time when it is not in use. I am not aware of any stretch of track which both routes must use if the proposed split configuration was implemented even if the Northbound platform approaches get very, very close to each other.

Inherently the "Camden Town" problem seems entirely down to managing passenger volumes in a limited space. Currently there is one often grossly crowded central link passage between northbound platforms with a similar set up southbound. Add in people actually entering or leaving the station and the lurkers clogging the link corridor waiting by the Next train indicators and voila the central cross link appears to be the core problem.

OK a few "in the know" passengers know about and already use the poorly signed link passage at the south end of the platforms. Inherently the answer surely is to get on now and create additional large capacity links between the two north and southbound platforms which with suitable signage should handle most of the route interchange flows, and free up the central passage mostly for entry/exit. I recognise that TFL also want to make the site fully accessible, but given the local largely NIMBY perspective to planning permission applications for almost any surface level changes that dream seems a very long way off. However it would be rather difficult to find grounds to reject an application by TFL today to create additional inter platform passageways located so far below ground that few if any surface properties can hear the existing trains.

to split the branches does indeed need additional cross passages.

The latest proposal for the new entrance is the best yet and stands a better chance of getting approval. It includes lower cost housing to aid the process.

This will greatly improves flows around the station and make the split more viable.

Simply setting the points would not work.

[alpinejohn]

" simply setting the points would not work" Sorry I just want to understand what you mean? Are you saying there are track conflicts which need addressing? or, as I suspect, the track-work is not the problem, but the existing inter platform cross passageways cannot handle the additional interchange passenger flows.

[aslefshrugged]

To me the obvious problem with splitting the Northern Line is that there is only one depot on the south end of the line at Morden. I believe there will be a couple of sidings at Battersea where two trains could stable overnight but other than that they're going to have to wait for the first train to make the trip down from Golders Green or Edgware before they can send a third northbound.

[Chris M]

alpinejohn do take a look at the London Reconnections and Ianvisits articles about the Camden upgrade. The existing station is too small to cope with either the current interchange traffic or the current entry and exit traffic, let alone both together. TfL have learned the lessons of the first plan and the latest proposals will not face anywhere near the same objections (it's a different scale, in a different place, with very little demolition for example) and they are also applying for the planning permission for the over-site development (OSD) separately to the new entrance and below-ground works so any objections to the latter don't derail the former.

Doing only the below-ground works is not viable, as surface access would be needed anyway for construction access and emergency exits and so you'd be paying the majority of the costs for probably at most 50% of the benefits. Even if you could build just the below-ground passages with nothing at the surface, adding a new entrance to them later would be more expensive and more disruptive than doing them at the same time.

[melikepie]

If you ignore the problem of fitting longer trains in sidings, could a longer train be added if the train was walk through? That way it wouldn't matter so much if carriages were stuck in tunnels

[whistlekiller2000]

Feb 9, 2017 13:20:18 GMT melikepie said:

If you ignore the problem of fitting longer trains in sidings, could a longer train be added if the train was walk through? That way it wouldn't matter so much if carriages were stuck in tunnels

The problem with this is you can't really ignore not being able to fit them into sidings now can you? 

[aslefshrugged]

Feb 9, 2017 13:30:22 GMT whistlekiller2000 said:

Feb 9, 2017 13:20:18 GMT melikepie said:

If you ignore the problem of fitting longer trains in sidings, could a longer train be added if the train was walk through? That way it wouldn't matter so much if carriages were stuck in tunnels

The problem with this is you can't really ignore not being able to fit them into sidings now can you? 

Especially if one end of the train ends up over a set of points

[crusty54]

Feb 9, 2017 13:20:18 GMT melikepie said:

If you ignore the problem of fitting longer trains in sidings, could a longer train be added if the train was walk through? That way it wouldn't matter so much if carriages were stuck in tunnels

your idea would cause masses of delays at stations making the overall service far worse.

The problem of the last car at Baker Street eastbound illustrates the point. No doors can open. Serious confusion as new users don't realise the train is in the station.

[John Tuthill]

Feb 9, 2017 13:20:18 GMT melikepie said:

If you ignore the problem of fitting longer trains in sidings, could a longer train be added if the train was walk through? That way it wouldn't matter so much if carriages were stuck in tunnels

Apart from the additional unloading time it would incur

[North End]

Feb 9, 2017 13:20:18 GMT melikepie said:

If you ignore the problem of fitting longer trains in sidings, could a longer train be added if the train was walk through? That way it wouldn't matter so much if carriages were stuck in tunnels

The problem is that even one set of doors not opening causes problems by extending dwell times. This already happens at Camden Platform 4 in particular. Unfortunately, when you're into high frequencies only a few seconds is enough to become a constraint which constrains the whole line.

Likewise, the problem with splitting the service is that no matter how efficient the interchange arrangements are at Camden, it simply won't work if every trains has an extended dwell time whilst half the train empties out and another large batch join. The problem is that there aren't many good alternative ways of getting from the Edgware branch towards the city, so reality is a *lot* of people are going to want to make the change at peak times. Meanwhile, at off-peak times, the Charing Cross branch tends to be more popular from both northern branches. I can't see it going down too well for the Barnet branch to lose their off-peak direct Charing Cross service.

[norbitonflyer]

Feb 9, 2017 11:42:23 GMT alpinejohn said:

" simply setting the points would not work" Sorry I just want to understand what you mean? Are you saying there are track conflicts which need addressing?

No - if it wasn't for those pesky passengers you could split the service tomorrow. Indeed it has been done in the past when there were problems with the points at Camden.

[alpinejohn]

Feb 9, 2017 16:51:32 GMT norbitonflyer said:

Feb 9, 2017 11:42:23 GMT alpinejohn said:

" simply setting the points would not work" Sorry I just want to understand what you mean? Are you saying there are track conflicts which need addressing?

No - if it wasn't for those pesky passengers you could split the service tomorrow. Indeed it has been done in the past when there were problems with the points at Camden.

Thanks for the confirmation - I thought I had misunderstood something and some real track changes were needed to separate and enhance line capacity.


Apologies to the Mods I have a feeling this and related posts might be better split off into a new thread about Camden Town - even if it leaves the current "longer trains" thread a bit disjointed?



So about Camden Town and those pesky passengers..


Thanks to Chris M, I have spent a few hours ploughing through several interesting web articles and related papers and agree the new plans seem to have a reasonable chance of eventually getting the OK, even if the new plan still entails seeking some compulsory purchase powers and may also impact on one of the area's long established markets.

What worries me now, is the obvious disconnect between the Battersea extension opening date and the rework of Camden Town allowing the services to be separated. The Camden Town timeline is now : 2018 Public Enquiry : 2019 Govt decision/TWA : 2023-4 revamped station complete. Given recent history of TFL project timetable slippages(Croxley) I think those dates need to be seen as a very optimistic aspiration - with a fair prospect that the actual commissioning date could be a good few years later than TFL would like.

Those "aspirational" dates contrast sharply with Battersea where the starting gun has been fired and in large measure the planning roadblock has been cleared. So given a fair wind, their planned completion date of 2020 seems deliverable. Inherently how plausible is it to service the new extension without actually splitting the service?

One table in the "London Reconnections" paper caught my attention - the proportion of passenger traffic split between interchange, entry and exit. At present interchange is a relatively small share. This tempts me to consider hand-grenade throwing mode, and ask IF LUL really need to split the service from 2020, then perhaps the logical solution would be for LUL to totally close Camden Town for all entry/exit (except during emergency) until the renovation is complete. A less extreme alternative, might be to simply discover faults and unfortunately close down indefinitely all the existing escalators, as this would probably have a similar effect. Looking at the street plan there appear to be other tube and mainline stations within 15 minutes walking distance which could take up a lot of the slack (the time-frame apparently considered reasonable if/when Watford Met closes). Closing off street access would however ensure that interchange traffic would then have exclusive use of the existing passageways, and probably provide ample platform capacity for interchange without extended dwell times.

I doubt this approach would bode well with the good folk of Camden Town, but splitting the lines has been an integral part of the Battersea extension for a long while and if planning delays mean Camden Town station is not ready, then what else can they do?