New tube for London stock

New trains will in the future move away from traditional design standards. There has always been rolling changes in standards on the tube normally starting with an innovation on one particular stock shifting to the design of others. An example is the innovation of externally hung doors first introduced on the 1992ts. When that became the new design standard is has been a feature of all since introduced featured on the 95/96/09 and S7+8 stocks. The new Piccadilly trains will likely serve as the first of the newest generation of walkthrough double door trains. All trains will more than likely follow this. 

They will be of a different design according to the NFTL feasibility report  "NTfL has identified that it is possible to provide an inter-car gangway by altering the Tube train design to incorporate an articulated configuration with more, shorter carriages. By positioning the vehicle bogies under the ends of two adjoining cars, the relative vertical and lateral movement of the carriage ends is significantly reduced." 

This is not just about the positioning of doors but a move to a new design of train . The double doors will obviously help handle the crowds if 33-36 TPH that is to be handled by the comparatively older Bakerloo, Central, Piccadilly and W&C lines when compared to the Victoria. The design will also allow trains to travel at higher speeds on all the lines they serve with smaller cars allowing trains to negotiate the tight junctions and bends that exist on the lines they serve. The Jubilee will be no exception. 

At a late stage in development it was decided that S stock should provide level access to platforms, and this has generally been achieved with adjustment to track and platforms. This results in larger gaps on curves, and train-based gap fillers were considered but dismissed due to additional points of failure. A trial is planned at Baker Street of a platform based active gap filler, and these are planned for the next generation tube trains at places like Bank (Central). However, it is not considered possible to lower the floor level due to already restricted space, and they will cover the platform edge similar to current trains. The plans for eventual full auto-operation include raising all platforms to the new train heights, as well as PEDs, but that would be sometime in the future!

Japan is now quite advanced in installing PEDs, some on lines with mixed stock. They have designed PEDs which can cope with these dynamically, recognising which type of stock is arriving.

So the existing PEDs on the Jubilee could be replaced with such as these before new stock is introduced, allowing an extended period for the changeover.

I can confirm that an awful lot of research work went into door positions, widths, vestibule and standback dimensions on the NTfL design brief and specs - to balance loading & station dwell times along with the engineering desire for shorter car 'units' that could be seen to effectively allow the use of a 'modular' design to suit the subtly different parameters for the various lines it was initially intended for.

The 'window' look - well, yes, it is an aesthetic and visual hint at some of the train architecturer than we knew 'worked' on older stock and that we where concerned we'd 'lost' on newer trains (such as the Vic line). But we were determined it wasn't a 'slavish take' on say the '38-TS.

It was driven by a desire to have smaller and non-curved window glass/units as on, eg the 92-ts, they are expensive and 'complex' to replace with sometimes longer periods OOS than you'd want. Against that we didn't want long, low windows as a) on the surface sections as well as in tube platforms you can't easily see out (although it mitigates somewhat against solar gain) and b) the car interior started to visually appear 'compressed' and so potentially subliminally unwelcoming. One thing we looked at with 'squarer' windows was it was simpler to supply and repair (potentially a cassette system), it gave a more regular rythmn to the train's interior architecture, especially when seen against the seat height, seat back and upstand dimensions and their relationship.

There was also the case that for both body strength and stability, along with the need to have enough vertical space to feed particularly the handled air flow, more 'uprights' may be needed - although this also has to be considered against the dimensions of body pillare adjacent to doorways.

This ain't the place to discuss the S-stock's car lengths/door positions and the fact that it ended up being effectively designed to cause more issues on certain platforms - it always struck me that it was as if some of the basic infrastructure requirements were not factored in or were dismissed by 'oh we can sort that'as if a magic engineering solution to reconstruct Baker St or Farringdon would appear.

PEDs - it was pertinent as to possible Piccadilly line deployment - there were some big ticket issues seemingly developing around such stuff as tube platform constructions and edge weight loadings, full height/half height, just tube not surface platforms and quite how you would manage the mixed fleet utilisation you'd find as you infiltrated new stock in with old. Then again, RATP seem to have managed some slick 'conversions'. Not sure where LU now stand on that issue - the money for the trains is now hard to find, let alone the signalling upgrade that was originally part of the 'package' so PEDS.....

Pretty small car windows, so is the small light fitted above them needed to boost any external light? That will result in uneven lighting in adjoining seats!

Evening all - and yes, as surmised, the window glass panels would not actually be squared off - quite how, with shading/stippling, etc, as used on current stocks, they are presented would be an issue for detailed design with the builders. The 'look' is of course down to individual's aesthetic tastes and reactions; as I mentioned some of the parameters that went into the design proposals were an attempt to consider the whole interior as an holistic environment as we'd become concerned that some of the proportionality and relationships between key elements of the interior could be reconsidered and made to work better.

Re; lighting - the 'back lighting' is there primarily not because of window size as such as in tube sections there's no light anyhow, but we had feedback and evidence that in a crowded tube train (no jokes please) with standing passengers in front of seated ones, deep shadows occur so, if you're seated and say trying to read, the light levels are poor to patchy. The back light is intended to assist this as well as help accentuate the car 'shape'.

The W&C only has five trains at present. I doubt there is room for ten - the end to end journey time of less than five minutes implies a headway of about one minute, and/or some very short dwell times at the termini.

As the picadilly has only 78 trains at peak now on current timetable and can only just cope with that many i assume the 94 trains are for 36tph 

An economic case for replacement of the Bakerloo fleet has yet to be made, and yet the TfL Programmes and Investment Committee on 20 July 2020 are advised that due to their age, Bakerloo line trains complete a Programme Lift cycle approximately every 15 months, whilst the latest trains only undertake this after ten years! Currently it seems the Bakerloo trains will just continue as heritage trains do, with maintenance as required!

Could there be a pause in the new stock?


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Could the 1973 stock when replaced on the Piccadilly line be used on the Bakerloo line ?

Agreed the Bakerloo stock has potentially got less mileage on the clock and has had extensive works. It also has more capacity I would imagine too.

The first 1983 tube stock did underscoring on the Bakerloo to check the gauge. This was to ensure clearances for the diversionary route to Elephant and Castle. I don't recall whether the train went to Queens Park though. Longer cars would be an issue at the curved platforms.

Also a 1973 tube stock car has been a regular visitor in the guise of the track recording train.

As others have said, 1973 tube stock is hardly any younger than 1972 tube stock, but has arguably had a harder life.