Co-acting signals at different points on the line

Discussion in 'Infrastructure & Stations' started by Muzer, 19 Sep 2019.

  1. Muzer

    Muzer Established Member

    Messages:
    2,718
    Joined:
    3 Feb 2012
    When Waterloo station's lower-numbered platform were rebuilt a couple of years back, some of them were provided with a gantry for the signals. This gantry also spans platforms 7 and 8, but these platforms are longer than the rest, so the front of the platform protrudes beyond the gantry and a long train would be stopped in front of it. As a result, co-acting signals were installed in the six-foot, but unlike normally they were installed at different points along the line to the main signals, since they had to be in front of the longest trains to use platforms 7 and 8.

    Other than the London Underground (where there is an example at Chesham), are there any other examples of this in the country?
     
  2. Registered users do not see these banners - join or log in today!

    Rail Forums

     
  3. Surreytraveller

    Surreytraveller Established Member

    Messages:
    1,545
    Joined:
    21 Oct 2009
    There's a few on the North Kent (can't remember where off the top of my head)
     
  4. ComUtoR

    ComUtoR Established Member

    Messages:
    6,321
    Joined:
    13 Dec 2013
    Location:
    UK
    I can't think of any on the North Kent :/
     
  5. Surreytraveller

    Surreytraveller Established Member

    Messages:
    1,545
    Joined:
    21 Oct 2009
    Chatham Mainline I think there's one at Gillingham? I thought there might be some further towards London - Woolwich maybe? Can't remember
     
  6. ComUtoR

    ComUtoR Established Member

    Messages:
    6,321
    Joined:
    13 Dec 2013
    Location:
    UK
    EK4110

    I checked the map and couldn't see one at either Woolwich stations. Not the worlds best map; because The Co-Actor at Waterloo East isn't listed !
     
  7. Llama

    Llama Established Member

    Messages:
    1,562
    Joined:
    29 Apr 2014
    Bradford Interchange had one installed at the end of platform 1 last October when it was resignalled. It is referred to as a 'stand out signal' with a separate ID (MM6251) to the normal platform signal (MM6261) but providing the same movement authority so the official literature says.
     
  8. moggie

    moggie Member

    Messages:
    378
    Joined:
    2 Jan 2010
    Location:
    West Midlands
    Indeed, EK4110 but there's nothing particularly unusual in terms of the positioning, provided to mitigate the sub-optimal sighting of the main head on the left hand bend approach obscured by station structures.

    I understand the Waterloo signals are staggered some longitudinal distance apart which attracted some ire from the drivers staff side at the time. I'd say they are somewhat unique in this respect.
     
  9. edwin_m

    edwin_m Veteran Member

    Messages:
    17,270
    Joined:
    21 Apr 2013
    Location:
    Nottingham
    This would be the more usual arrangement, also seen at Liverpool Street and Manchester Piccadilly and many other places where there is a set of points near the platform end and a full length train would foul them. The first signal coming out of the platform will only clear if the second one is clear, and will never show a less restrictive aspect. These aren't actually co-actors.
     
  10. macka

    macka Member

    Messages:
    26
    Joined:
    4 Oct 2012
    A longer platform may have one or two of these signals when the platform is often used by shorter trains and the platform signal is out of view. A few platforms working like this still exist at Glasgow Central but some signals has already been replaced by banner repeaters.
     
  11. Llama

    Llama Established Member

    Messages:
    1,562
    Joined:
    29 Apr 2014
    @edwin_m ,
    Those are a different type of signal, effectively a mid-platform signal, they each convey individual movement authorities to a driver. You are right however that a train proceeding from say platform 12 at Piccadilly will only be able to do so when both that signal and the one at the end of platform 9 are clear, but that is to do with the fact that the first signal is two aspect able to show red/green only (with subsidiary for shunts) so the interlocking dictates that they can only show a clear aspect once the platform starting signal at the end of platform 9 is also showing a proceed aspect.

    Platforms 3 and 4 at Lime Street had exactly the same setup as at Piccadilly prior to last year's resignalling.

    For normal moves a train would receive a clear signal (green) at say MP380 on platform 12. This signal, like MP378, MP376 or MP390 which is the 'first' signal on platform 9, can only show red, green or a subsidiary proceed aspect. They have their own right-away indicators. The next signal after a train has left platform 12 is MP374 which is a three aspect signal at the end of platform 9 which must be displaying a proceed aspect but that signal does not repeat the same indication or movement authority as that received at say MP380 on P12. A driver will only receive their indication of route from MP374, and MP374 obviously might show a single yellow aspect.

    The signals at the end of platform 1 at Bradford both show the same indication - if MM6261 is showing single yellow aspect then MM6251 also shows a single yellow aspect etc. just like a co-acting signal would, but the signals are not in the same plane, they are two chains apart. Drivers are aware that both signals there provide the same movement authority.
     
    Last edited: 20 Sep 2019
  12. edwin_m

    edwin_m Veteran Member

    Messages:
    17,270
    Joined:
    21 Apr 2013
    Location:
    Nottingham
    Thanks for the clarification. As far as I can remember the ones at Liverpool Street are the same as you describe at Bradford and I think their separation is similar too.
     
  13. plymothian

    plymothian Member

    Messages:
    648
    Joined:
    26 Sep 2010
    Location:
    Plymouth
    Penzance platform 4 has a co-acting on the signal gantry angled down towards the driving cab.
     
  14. 4-SUB 4732

    4-SUB 4732 Member

    Messages:
    824
    Joined:
    7 Jan 2018
    These ones were the cause of very large issues between ASLEF and NR from memory as their argument was the train shouldn't be starting ahead of the main aspect. Seems fair to me.
     
  15. 4-SUB 4732

    4-SUB 4732 Member

    Messages:
    824
    Joined:
    7 Jan 2018
    There's the one protecting Blackheath Junction on the up Bexleyheath, L310 or whatever it is. End of Kidbrooke Tunnel.
     
  16. ComUtoR

    ComUtoR Established Member

    Messages:
    6,321
    Joined:
    13 Dec 2013
    Location:
    UK
    TL460 (I think) As you say, 'Up Bexleyheath' not the 'North Kent'.

    I don't know enough about signally specifics to say for sure but when it got installed (very recently) I get the impression that it's 'backwards' The main signal is on the gantry and is aligned so that the Driver can see it through the tunnel. The new Co-Actor is placed (rather stupidly) where the normal placement of a signal would be (on the left).
     
  17. carriageline

    carriageline Established Member

    Messages:
    1,827
    Joined:
    11 Jan 2012
    Correct. I believe L460 was a multi SPAD. Am I right I’m saying as you come out of the tunnel, you are on a curve. That combined with the tunnel made a signal on the left hand side hard to see, which is why it’s on the right. Makes sense.

    But perhaps having the signal on the right caused confusion, hence it being SPAD. The co-actor was probably then installed to give a clearer understanding on the signal? IE once your out of the tunnel, it’s clear on what aspect applies to the down line?
     
  18. edwin_m

    edwin_m Veteran Member

    Messages:
    17,270
    Joined:
    21 Apr 2013
    Location:
    Nottingham
    If we're now talking co-actors in general Nottingham has one at right angles to the track, in a bay platform that's only just long enough for a 4-car where it shines through the cab window.
     
  19. ComUtoR

    ComUtoR Established Member

    Messages:
    6,321
    Joined:
    13 Dec 2013
    Location:
    UK
    It's a pretty sharp turn and only 20mph. The placement made perfect sense but when you came to a stand, the signal effectively disappeared as it was off set by quite a factor.

    More a sighting issue but I'd accept confusion as a factor too. Very easy to miss and/or disregard anything not in your direct line of sight.

    If it wasn't hidden by the curve I'd agree. If you are pulling round the curve and are sighting the new Co-Actor then you have just had a SPAD. The signal is so badly sighted it isn't worth having.

    NR love to hide signals behind walls, curves, buildings, bridges....

    Can you SPAD a Co-Actor ?
     
  20. Joseph_Locke

    Joseph_Locke Established Member

    Messages:
    1,831
    Joined:
    14 Apr 2012
    Location:
    Within earshot of trains passing the one and half
    On behalf of those who design such things for a living, your statement is at least a crass exaggeration.
    The industry spends a lot of time and effort not doing these things.
     
  21. class 9

    class 9 Member

    Messages:
    475
    Joined:
    18 Nov 2010
    There’s one at Worksop station.
     
  22. ComUtoR

    ComUtoR Established Member

    Messages:
    6,321
    Joined:
    13 Dec 2013
    Location:
    UK
    Firstly in a thread about using co actors see the humor. Remind me what they are designed for..
    Secondly, No offense intended, my apologies if you felt that way.

    Now to the point.

    There are many signals that are indeed 'hidden' or very poorly sighted. Some cause Drivers to read across or read through. Whilst I accept the human factors involved, there is no denying the signals are poorly placed.

    We had a SPAD a couple of years ago at a junction. The signal concerned is well known for poor sighting. As is typical, a banner was installed AFTER the event. No proactive steps were ever taken and nothing is done until after an incident happens. The banner they have put in, again, might as well not exist because its been put in at the most stupid place. Granted it will have been placed specifically to whatever standards there are but if you don't see it until its too late, then its kinda pointless. What should happen is that it is brought forward so that you can actually use it to confirm the aspect and take action if required.

    Grove Park is infamous for its crap sighting. You sit at the platform at Hither Green and you have to remind yourself each time that the signals you are seeing are not yours. Why ? Because the one you want is hidden behind a gantry. Because you always sight the signal behind the one you need you can see a green in front of a Red.

    Maybe that's because or historic placement..

    Have a look at our new installations. Signals are still placed where you can't see them. Cue more SPAD(s) ! London Bridge at Corbetts Lane. What person installed that abomination. The junction indicator is hidden behind the gantry ! Guess what happens. Yep, wrong routes. It's a 60mph approach and you can't see the indicator you need :/

    Tunnels are fun too.

    We have a couple of tunnels where the signal sighting is amusing. Again, I will accept that there are various factors involved and we are constrained by infrastructure etc but you drive through the tunnel and suddenly, out of nowhere, a signal will appear to drop down from the roof. This signal is invisible on approach and its another set of signals where your sight line sees the one behind. You also get tunnels where because of the gradient you also see the one behind you need.

    I get there are standards and I get there are infrastructure constraints but this does mean that signals are behind curves, bridges etc.
     
  23. Joseph_Locke

    Joseph_Locke Established Member

    Messages:
    1,831
    Joined:
    14 Apr 2012
    Location:
    Within earshot of trains passing the one and half
    Forgive me, but the implication was that we didn't care.

    However, how many of the examples were sighted and built in the RT/NR era? Not many, I'd guess, which was my point - in a properly designed scheme there should be no need for co-acting signals or ROL / PROL nonsense, though I'll grant that high(er) speeds drive banner provision on a lot of routes, but even then it would only be a last resort after trying to find a banner-free solution.
     
  24. ComUtoR

    ComUtoR Established Member

    Messages:
    6,321
    Joined:
    13 Dec 2013
    Location:
    UK
    Not a clue. I've been driving for 15+ years and most were there before I even started.

    But our new schemes all have sighting issues. The route learning packs that are issued before, during and after the works all contain sighting issues. Corbets Lane is brand new. We sit in the briefs and within a few drives you are just saying 'someone is gonna SPAD that' and they invariably do. Seriously, take a cab ride down Spa Road and play hunt the junction indicator at Corbets. Or take the diveunder from Lewisham and play 'guess which signal is mine' but watch out for the Dinosaur

    Grove Park is being resignalled and I am physically dreading it.

    Don't know what these are. (thanks in advance)

    The new banner protecting Nunhead only came about after an incident. The railway as a whole is not proactive. Even when things are reported, nothing happens until there is an incident. Whenever I am asked to check sighting issues by the Signaller the default is 'can you see it at the magnet' If you don't see it by the magnet, it's pretty much too late. Yes people should be driving based on the previous signal. Where we are adapting to banners and poor sighting it just causes delays. A banner can have a positive effect by allowing an earlier point to accelerate.

    I don't mind a banner because I can accept the constrains of infrastructure or landscape. We have a couple of signals that are literally behind bridges. Even when the area was re-signaled, they just get replaced. I find it very odd that the ones that were in plain sight on a straight bit of track were moved a few foot yet the one behind a bridge is left.

    Blackheath had a banner installed when it was re-signalled, yet they could have shifted the signal slightly to the right (as Catford Bridge/Greenhithe) It's also approach control so the banner becomes pretty insignificant and you learn to ignore it.

    Part of the problem is that once the signal goes in, it stays there. Any sighting issues or infrastructure problems and it just becomes part of the route risk. WE are moving to an era where there is supposed to be a better relationship between TOC and NR but I see these new schemes going in and I just think that nobody has seen it from the Drivers perspective.
     
  25. pompeyfan

    pompeyfan Established Member

    Messages:
    2,866
    Joined:
    24 Jan 2012
    Talking about being reactive rather than proactive, off indicators are another that could be resolved easily. There’s still a few of the old stencil type indicators that are impossible to see and could quite easily be replaced, and invariably are after a couple of tips on the red.

    talking of newer signalling issues, Portsmouth Area resignalling scheme put 11 signals in 1m 32ch, 5 of them are between Portsmouth harbour and Portsmouth and Southsea. A 12 car will occupy 3 signal sections when waiting for a platform at the harbour. Crazy waste of money.
     
  26. MarkyT

    MarkyT Established Member

    Messages:
    3,984
    Joined:
    20 May 2012
    Location:
    Torbay
    Including those daft down direction running in signals on the back of Portsmouth Harbour's platform starter gantry. It was in my opinion a rather poor interpretation of standards that had recently changed after a number of platform collisions associated with permissive running. The new idea at the time was to reduce the distance as much as possible from the signal authorising a permissive call on or shunt towards an occupied platform. Having signals in these positions at through stations can make some sense as they're also of use for closing up following trains, but at a terminal they are utterly pointless. More recent schemes have not been so profligate with the numbers of signals as engineers have interpreted the standard in different ways and the relevant clauses have also been revised to be more clear as to what is reasonable. Unfortunately the Portsmouth scheme was being developed just at the time when the standard changed and there were no precedents for how to interpret it.
     

Share This Page