I don't know whether TfL has the same sort of specs as the TOCs giving capacity requirements at various times of day, of if they do, who set's them. TOCs have the DfT's expectations whereas TfL might be more self specifying as I doubt the DfT has anywhere near as much knowledge of true metro performance. Inevitably stock that has such diverse passenger demands has to offer a compromise, however despite many opinions expressed here about the wisdom of double-ended routes, the costs of terminating facilities in central London means that a well designed through service is both far more efficient yet has considerably lower costs.
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Nym
Established Member
As I’ve said many times…
999666 / TRC666 is NOT a standard 73 Trailer. The dynamic profile is very different
It did cross my mind that some wag would mention it, but for completeness the Circle line (no comparison to a linear route) should be added and possibly the Bakerloo, (which doesn't really have much of an off-peak flow from central London to Elephant and Castle).
Yes,
But it still fits. It is still a 73TS car.
Altering dynamic profile is relatively insignificant.
They have not chopped out several metre of body length - which is what the comment to which I was responding had suggested needed for 2024TS.
notverydeep
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TfL doesn't have explicit capacity requirements and specifies its own services and hence capacity (so no PIXC, that is Passengers In eXcess of Capacity) measure). The capacity of a train service is hard to define exactly. A maximum number of people that can be accomodated will depend on passengers willingness to be crowded. From demand data it can be concluded that in the most disrupted, busy situations the limit is around 5 passengers per square metre, with 4 / square metre the more normal maximum at peak times. For safety planning, 7 passengers per square metre is the convention, but there is no evidence of this being achieved as an average across a train (even though it may occasionally feel like it). It would be analogous to the 'how many students can fit in an old-style mini competitions with people having to carefully arrange themselves. Much earlier in my career I can remember a test with a DLR train at Beckton where some students were paid to do an exercise of this type!
The objective of service specification is to maximise social benefit, normally by minimising customer generalised journey time (within the network's capability and available resources of course). Forgive me if you are already familiar with the concept of generalised journey time, but this is where the journey time includes a valuation of the 'weightings' that customers attach to different elements of journey time, as well as the value of non-time elements. An example of weightings would be that an average customer prefers a minute spent on a moving train compared to a minute waiting at the platform, or a minute in a seat compared to a minute standing on a crowded train. Non time elements includes things like how comfortable the seats are, the fare paid and how secure they feel on board.
The DfT does set the framework by which these things are evaluated through its Transport Analysis Guidance (https://www.gov.uk/guidance/transport-analysis-guidance-tag). TfL then uses a document called the Business Case Development Manual to implement this framework on its own projects (linked here: https://tfl.gov.uk/corporate/transp.../foi-request-detail?referenceId=FOI-4306-1718). This expands on the DfT guidance includes parameters specific to metro operation and TfL that are set by TfL using its own research or research it has commissioned. The specification of new train types would follow this framework of evaluation and TfL's normal governance processes. The National Rail network has its own version of the framework called the Passenger Demand Forecasting Handbook (PDFH), some details here: https://www.raildeliverygroup.com/pdfc/about-the-pdfh.html.
Completely agree with you on double-ended routes. These make much better use of Central London infrastructure and train fleets, hence the Elizabeth line and proposed Bakerloo line extension and Crossrail 2. The weakness of Thameslink in this context, is that it is trying to serve a selection of more regional markets (almost Inter-City in the case of Brighton to Cambridge), where customers have a higher expectation of comfortable seating, toilets etc. that are less important for metro trips. As you say - almost all services end up being a compromise between the competing needs of different passenger groups...
[apologies for the essay!]
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Don't apologise for the lengthy post, it's very informative - stuff that generally isn't accessible to lay persons, (which includes me). Whilst I hadn't heard of the term, 'generalised journey time', I can appreciate that the more intensive a service is, the more factors not instinctively associated with a passenger's view of journey time come into play, but I would maintain that services that feed the needs of metropolitan London are unlike those of any other part of the UK, and that difference tends to slant the type of analysis of generalised journey time where some weightings become either total or conversely negated.
Unlike most UK railway systems, but in common with some similar world city networks, there are absolute parameters that are practically fixed, in particular line capacity, (where an unacceptable cost would be needed to increase the infrastructure's contribution). This is especially acute in London with it's pioneer underground railways, and relatively constrained national rail early industrial revolution loading gauge. LU has for many years operated trains that have the smallest cross section, are maxed out for capacity in the peaks by seating that preserves the maximum standing room, runs maximum trains length consists (even dwells where both end cabs are completely within the tunnels), to timetables with the tightest headways. So however much value a few passengers place on having a seat for a relatively short journey, (ignoring more selective preferences for transverse arranged seats), the option of satisfying those special preferences are crowded out by the absolute requirement that the trains deliver on the fairly basic need to just get passengers to their destinations.
absolutelymilk
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Anybody know how either the max acceleration or max power output compares to the previous stock? Trying to get a sense of how much quicker journeys will be
torontoaddick
Member
Acceleration will be capped to be the same as the existing trains until a new signalling system is installed on the line.
Nym
Established Member
Not to be purely argumentative. But you're wrong.
In addition to it not being the same size. There are some significant issues with depot space on the line that are not simple to solve. London Road depot cannot accept any additional length on 1-4 road, and if one did any form of refurbishment on the depot, 1-4 road would be rendered non-usable. In short, the Bakerloo Line extension would be needed to access the additional depot space for any, and I mean ANY extra length of stock to be able to be used. Then add to this, there isn't any more space for additional roads at any of the Bakerloo's existing depots.
Oh, and Croxley is dead now so no chance of a depot up there combined with a re-extension to Watford.
At university (alas) some 40-50 years ago we used to call it "perceived journey time". There are comparable issues on road, a minute waiting in a traffic queue is perceived longer than a minute driving along, hence drivers will prefer a longer distance route where they keep moving.
A notable one for public transport is the break point between needing a timetable for a specific journey, compared to just "turn up and go" for the next one, which varies depending on various criteria.
On the matter of local routes across, say, inner London, it has long been preferable to operate these across from one side to the other, so as some get off others get on, maximising the usage. This particularly drove the design of early urban bus services, and thus it is quite contrary how London buses have gone the other way in recent years, most no longer crossing the centre, leading to all sorts of inefficiencies, it seems just for the convenience of arranging franchise contracts run out of one depot. Such London bus routes long ran out of two depots, one each side of the centre.
That's not unique to London, many city bus services do t go across the centre, or have stopped doing so.
When I first went to Nottingham university in the early 2000s, many bus services went across the city. That was stopped en masse, the reason cited was that traffic congestion in the city centre made the timetable unreliable. By splitting the services, so the theory was, the timetable would be more robust.
absolutelymilk
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Thanks, why is that? Do you know when the new signalling system is planned for? (I'm assuming there isn't already a thread for that). Do you know what the acceleration/max power output will be once the new signalling system is installed?
There are no plans with a timeline for a new signalling system on the line. An interim control system upgrade was completed in 2018 which has improved reliability. Works are currently ongoing to ensure the signals are compatible with the new rolling stock, the primary difference people will notice is relocation of signals and installation of co-acting signals.
Was that the replacement of the punched card readers etc with digital control of points and signals? ISTR reading an article years ago talking about how many of the junctions were still controlled with paper tape and punched card machines saying back to the 1930s.
ThameslinkUser
Member
Yes.
Not quite. Firstly the programme machines and punch roll used on the Piccadilly dated from the 1960s and not the 1930s. The physical punch roll was replaced at most sites with a digital equivalent as part of the CTFS system developed and installed by Tube Lines over a decade ago. This has further been surplanted with the Picu system which you can read more about here
bluegoblin7
Established Member
Ish.
Physical control of points and signals across the Piccadilly line is from Interlocking Machine Rooms containing, by and large, Westinghouse V-style lever frames. These were remotely supervised from Earl's Court control room, with local programme machines calling the relevant routes as necessary. Things could also be controlled directly via buttons at Earl's Court. The programme machines and associated systems at Earl's Court were the main source of unreliability. The Programme Machines used punched rolls of plastic to call the routes per standard LUL practice, although many had been bodged to have some level of digital interaction in recent years.
Supervision of the local sites was moved to the new control room at South Kensington in 2019 as part of the PICU (Piccadilly Interim Control Upgrade) programme. This replaced the majority of Earl's Court and the programme machines, but retains the existing local interlockings with no substantial changes to these as part of PICU. Other changes have taken place as part of other works.
FWIW, the Control Room at South Kensington went live in Spring 2018 rather than 2019, although it wasn’t fully commissioned until 2019, most of the line moved there in 2018.
Late reply but wouldn't the train have an induction loop for those with hearing aids?
I actually feel the r211 trains have a good information display system. The digital maps are good on screens, the sides the door open on are visual and a dot matrix display for signposting stations.
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absolutelymilk
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Is this for all the time or only when they're on time, i.e. will they have the same schedule but if they're running late they can use the same power, or will the power be capped to be exactly the same at all times?
bluegoblin7
Established Member
All the time, it will be a permanent cap lifted only if new signalling is provided.
Nym
Established Member
Until new signalling, re-acceleration rate is one of the parameters of the signalling system so any changes to train performance would need re-signalling of any speed control on approach loops. (Among many many other things.)
If I recall correctly, the acceleration rate of the S8 stock, at the time of introduction, was capped roughly to the rate of the then, by comparison, sluggish A60/62 stock. The rate of acceleration was eventually increased (around 2015?) to a rate which is most certainly far superior to the A stock. a few years following withdrawal. As far as I am aware, this was done under the same signalling system which remains in place today (asides from the areas now under ATO).
I assume the same could be done for the 24ts, where the acceleration can be increased to something superior to the 73 stock, but not as great as under a new signalling system, once the old stock is withdrawn.
I assume the same could be done for the 24ts, where the acceleration can be increased to something superior to the 73 stock, but not as great as under a new signalling system, once the old stock is withdrawn.
Nym
Established Member
The timing loops on SSL were adjusted and the TrackLink III tags used to tell the train how hard it can drive if I'm remembering correctly.
100andthirty
Member
S stock was set for two lowish performance levels on the old signalling system and full performance on the new signalling. In principle it was A stock acceleration and top speed north of Baker St and C Stock acceleration (slightly higher) and top speed (lower) everywhere else. Switching was carried out though the Correct Side Door Enable/End Door Cutout system.
As I understand it, some years since I was last involved, these different performance options don't exist for the Piccadilly line.
As I understand it, some years since I was last involved, these different performance options don't exist for the Piccadilly line.
To be quite honest, it was only after the introduction of the S8 stock that one really realised how slow the A stock was in taking off, having been used to it for years.
The 73 stock acceleration is far better (compared to the A stock) and decent enough for modern standards, so not such a big deal I think as the new stock will probably perform to the upper level of a 73.
Regardless though, it's honestly such a waste to not have trains perform to their full performance for such a long time!
The 73 stock acceleration is far better (compared to the A stock) and decent enough for modern standards, so not such a big deal I think as the new stock will probably perform to the upper level of a 73.
Regardless though, it's honestly such a waste to not have trains perform to their full performance for such a long time!
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Not necessarily, the additional cost for slightly raised power would be a small proportion of the whole cost - a benefit would be potentially greater reliability, sufficient performance to sustain services during a single or even multiple drive chain failures, and longer life between overhauls/replacement.
Between Hammersmith and Barons Court where the 73 and S Stock often run side by side, there's not really much in it acceleration wise, I would actually guess braking makes more of a difference! The S Stock looks like it can brake later, as you'd hope from a 40 year newer model
