Signal identifications

Discussion in 'Infrastructure & Stations' started by rdeez, 19 May 2015.

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  1. rdeez

    rdeez Member

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    Passing through the newly re signalled Wolverhampton the other day got me wondering. In 'existing' signalling setups - PSBs, lever frame boxes etc - the origin of the signal prefixes is usually the box name, Wolverhampton was WV, Gloucester is G etc. The new signals at Wolverhampton are WS xx and BS xx. I'm sure there's a logic to the labelling but what it is eludes me...can anyone enlighten me?
     
  2. swt_passenger

    swt_passenger Veteran Member

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    Usual alternative seems to be the initial letters of locations at either end of the line - so could it be e.g. Wolverhampton to Stafford for WS
     
  3. rdeez

    rdeez Member

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    Ah, you might be on to something there - it might have been "BW" at the Birmingham end of the station, not BS. I only got a glance. And that makes sense
     
  4. LNW-GW Joint

    LNW-GW Joint Established Member

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    Wolverhampton PSB was actually WN.
    Somehow the LMR ended up with Willesden, Wolverhampton and Warrington PSBs on the WCML all prefixed WN.
    At least now there's only Warrington.
    This site has all the details, old and new: http://www.railwaycodes.org.uk/signal/signal_boxesw.shtm
    The system means essentially that signals on the line from A to B are prefixed AB.
    I think BS is really BW (Birmingham-Wolverhampton).
    The way it is split up might also be something to do with the specific workstation control area in the new SCC/ROCs.
    Reading has ended up with "T", for Thames Valley I suppose.

    The WR method from Paddington was M or R (for Main or Relief line), prefixed with U or D (Up or Down) and followed by the milepost number.
    That way you could immediately locate signal UM30 on the Up Main near Twyford.
    I don't know if any of that will be retained in the new signalling.
     
    Last edited: 19 May 2015
  5. Tio Terry

    Tio Terry Member

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    PSB's used to use the first and last letters of their names - hence the 3 WN's on the former LMR - but I'm not sure what they are doing with ROC's.
     
  6. Railsigns

    Railsigns Established Member

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    That numbering system was only used for automatic signals.
     
  7. Nippy

    Nippy Member

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    And not being kept under the re-signalling as all automatics are replaced by signals that can be controlled to danger.

    Some may be kept where they are re-controlled only.
     
  8. swt_passenger

    swt_passenger Veteran Member

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    They'll probably use a different plan for each ROC on present form. That 'A<>B' style as used in the recent WCML and WM changes discussed earlier might not even be planned for anywhere else at all?

    I guess we'll see in due course...
     
  9. Deepgreen

    Deepgreen Established Member

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    I'm guessing that on this basis the new 'TL' prefix on signals around London Bridge means Three Bridges to London Bridge? I had initially assumed it was 'Thameslink'.
     
  10. A-driver

    A-driver Established Member

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    Round there the T just prefixes the original letter. So TL/TVC/TVS means three bridges London Bridge/three bridges vic Central/three bridges vic suburban etc
     
  11. swt_passenger

    swt_passenger Veteran Member

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    No, I'm starting to think it is only safe to assume that 'A<>B' style in the one area, i.e. the WCML and its associated routes.

    I think A-driver possibly hasn't quite got the whole meaning across, in this case it isn't Three Bridges TO London Bridge, but rather that part of the original London Bridge area is now controlled AT Three Bridges.
     
  12. A-driver

    A-driver Established Member

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    Yes-just re read my post and I didn't really explain the crucial bit that TL means three bridges London Bridge signal box panel in effect-so the current London Bridge/Victoria C or S signal box but now three bridges. Very simple really but surprisingly difficult to explain by typing!
     
  13. edwin_m

    edwin_m Veteran Member

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    The re-signalling of the former Trent box area also has prefixes that approximately represent the key places the section links together. I suspect the IDs have gone away from signalbox names because (a) many sections will be re-controlled to ROCs while keeping the same signalling, and they don't want to have to renumber everything and brief all drivers on the change, and (b) the ROCs will control such large areas that more distinction between their routes is seen as helpful.
     
  14. LNW-GW Joint

    LNW-GW Joint Established Member

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    For what it's worth, Shrewsbury-Crewe has been prefixed SC but is part of the Wales ROC.
    On the other hand in the same ROC Newport is NT and Cardiff is CF.
     
  15. Railsigns

    Railsigns Established Member

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    The 'A<>B' numbering style is mandatory for modular signalling schemes.
     
  16. swt_passenger

    swt_passenger Veteran Member

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    Thanks for that. What proportion of future schemes will be modular, do you think?
     
  17. The Planner

    The Planner Established Member

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    Stoke Derby is meant to be modular.
     
  18. collexions

    collexions Member

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    Of current CP5 live schemes the following are 'modular':
    > Derby - Stoke
    > Chester - Llandudno
    > East Nottingham

    That's under 10% of current schemes.

    Future schemes... seemingly no more common looking into CP6 workbank.
     
  19. MarkyT

    MarkyT Established Member

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    In more modern schemes (last 20 years or so) all 'autos' were actually 'controlled' or at least manually replacable by signaller using an individual or group replacement switch (or equivalent screen symbol) anyway. From a technical perspective there is little difference in the design, but it has been decided in recent schemes that the distinction between passable and non-passable signals, as they are defined in the rule book today, will not be made , thus all new signals are plated as non-passable. That is possible because today's verbal communication methods are so much more reliable and diverse, so the need to allow drivers to make a decision on their own to pass a red in some circumstances is becoming obsolete.

    The A<>B method is supposed to be default for new schemes and it works well on long trunk lines divided up into sections between significant nodes, but it can be rather complicated and possibly confusing at very complex junction sites between multiple routes, where a single geographic 'area code' based around a node or group of nodes might be more appropriate. That ideally still wouldn't be based on the control centre name itself, although due to project practicalities (especially where large areas of re-control are concerned) it could end up that way. The recent and ongoing East Kent resignalling uses the prefix EK which was a new code all to be controlled by the new Gillingham centre and the sectional appendix refers to this as East Kent Signalling Centre (EK). In theory, that area might be transferred to an EK set of desks anywhere, as could the related NK group of numbers, covering the Dartford area to Strood, and extending on to the Medway Valley, soon to be also controlled from Gillingham. The Dartford - Strood NK desks are currently at Ashford, and the move does not require a prefix change. Sectional Appendix refers to control for this area by Ashford IECC (NK).

    A coincidence

    Yes that's it. Keeping existing numbering is essential for re-control. You can subtly tweak the prefix as here, but relay equipment is all labeled up, and drawings and schedules tagged and numbered, using codes based on the particular signal numbers, so keeping the same numbers saves an immense amount of fairly pointless tedious design work with an inherent potential for human error. Clearly it's a little easier with SSI systems. There's still a lot of labelled bespoke wiring in lineside cabinets and all the related drawings though, so if there's no significant change to the track layout and signal positions. It's a lot easier to keep the same signal and point numbers and the same old interlocking configuration data, even if installed in new physical interlocking computers.

    Yes I think that's the intention whatever detailed method is used. Renumber once for all perpetuity, whatever happens with future ROC strategy and any intermediate temporary control locations.
     
    Last edited: 22 May 2015
  20. TDK

    TDK Established Member

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    The lettering refers to the route from A to B in general and also refers to a certain panel station in the box so from instance BS is Birmingham to Stafford and controlled by a different signaller then say OS that is Oxley to Shrewsbury, this is also noticeable when contacting the box where the signaller will answer "west Midlands Oxley Panel" for instance.
     
  21. Railsigns

    Railsigns Established Member

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    No; it refers only to the section of route. If a change of prefix happens to coincide with a change of workstation area, then it will be purely coincidental.
     
  22. edwin_m

    edwin_m Veteran Member

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    The signal number also used to identify it in the SSI identity and data files (without a prefix I think, as no signal number would be duplicated within the same interlocking). Changing this data triggers a whole mountain of safety-critical checking and sign-off, so that's unlikely to happen either.
     
  23. 30907

    30907 Established Member

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    In pedant mode, VS was Vic South Eastern (Vic Chatham would have been more accurate but obviously confusing!)
     
  24. A-driver

    A-driver Established Member

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    Ok, not arguing but when I signed roads down there I was always taught (and even the routes maps stated) that it was suburban, not southeastern.
     
  25. 30907

    30907 Established Member

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    In which case you may well be right, as the WTT Vic Suburban book covered all its routes and a bit more.
     
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