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Level Crossings @ Lansdowne, Sandymount, Sydney Parade: Excessive Length of Time Down

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Comments

  • #62
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,204 CMod ✭✭✭✭magicbastarder


    blobert wrote: »
    I've recently moved to live right beside Sydney Parade train station.
    you recently moved to somewhere with possibly the best train service in the country, and are now finding fault with how the trains are impacting your life.

    land values along that line are higher because of the train service, but if you're not actually using the train, you may have spent more than you needed to, because you're essentially paying for a service you don't seem to use all that much?
    it's like moving out beside the airport and being surprised that planes make noise on takeoff.

    we have good friends living within spitting distance of one of these level crossings; i've never heard them complain of it being an issue for them. but i suspect that's a consequence of adaptation; they probably just know to expect it and get on with things.


  • #63
    trellheim
    Registered Users Posts: 5,854 ✭✭✭trellheim


    Perhaps press for a pedestrian overbridge and the level crossings removed with your council and TD

    This topic comes up time and again here, it was a long running problem at Reillys bridge in Cabra/Ratoath road until... guess what... a brand new overbridge was built and the Level crossing eliminated , now you never hear about it. Have a long long read back here ( there were many posts about it ) and do the research

    Sam Russell is trying to point you at the same solution for Merrion Gates ... so why not read up on that, you seem to want to know the details so why not look into it , as I said the railways been there for 185 years


  • #64
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,204 CMod ✭✭✭✭magicbastarder


    magicbastarder wrote: »
    we have good friends living within spitting distance of one of these level crossings; i've never heard them complain of it being an issue for them. but i suspect that's a consequence of adaptation; they probably just know to expect it and get on with things.
    an aside - we reasonably regularly head out to our friends and it's a running joke with myself and my wife that our presence activates the level crossing we have to cross to get to our friends' house (we're lucky that we have a bus service that only leaves us with about 500m walk in total to get there).
    i'd say in the last ten times we've approached that level crossing, the gates have come down with us only a very short distance away, on at least half the occasions.


  • #65
    Sam Russell
    Moderators, Science, Health & Environment Moderators Posts: 19,335 Mod ✭✭✭✭Sam Russell


    trellheim wrote: »
    Perhaps press for a pedestrian overbridge and the level crossings removed with your council and TD

    This topic comes up time and again here, it was a long running problem at Reillys bridge in Cabra/Ratoath road until... guess what... a brand new overbridge was built and the Level crossing eliminated , now you never hear about it. Have a long long read back here ( there were many posts about it ) and do the research

    Sam Russell is trying to point you at the same solution for Merrion Gates ... so why not read up on that, you seem to want to know the details so why not look into it , as I said the railways been there for 185 years

    Here is a link to a thread on Infrastructure that deals with it.

    https://www.boards.ie/vbulletin/showthread.php?p=101479541


  • #66
    lucernarian
    Registered Users Posts: 9,235 ✭✭✭lucernarian


    goingnowhere wrote: »
    Line speed limit is 100kph and has been for 35 years and trains passing through Merrion Gates assuming they get clear signals (as is the design) should be at above 90kph)

    The rules on the DART are based on
    1. Level crossing must be CCTV inspected and are interlocked with the signaling system
    2. Full overlap protection is provided, so if gates are open, train is halted 200m from gates

    Elsewhere in the world (where the instances of level crossing accidents are much greater) the gates are timed to drop and be down 30 seconds before a train passes based on the fastest train


    For Merrion Gates the logic is

    Depart Blackrock, train gets a yellow signal which enforces a 50kph limit before Booterstown
    Loss of 30 seconds due the enforced speed limit due signals protecting Merrion Gates.
    Stops in Booterstown with a red signal.
    Doors open
    Merrion Gates are requested based on a timer
    Sydney Parade gates requested based on a timer
    Gates close and are confirmed closed by CCTV
    Signal clears to Yellow, next signals are Red (BN33), Red (BN31)
    Driver moves off
    Sydney Parade gates are confirmed closed by CCTV
    Signal clears to Green, next signals are Double Yellow (90kph), Yellow (50kph) this gives a profile where the permitted speed is greater than the braking curve
    DART even if it has past the first signal will pick up that the signal was retrospectively Green and give the driver 100kph
    Train arrives Sydney Parade with gates down and a yellow signal, the yellow signal is because Sandymount gates are not down
    Timer runs to call Sandymount gates
    Sandymount gates are confirmed closed by CCTV
    Train departs, the signal at Sydney Parade will move to double yellow (90kph)
    Next signal is yellow as Serpentine Ave gates are not closed, these trigger


    There is an upgrade to the DART ATP system coming which should allow DART trains to travel much faster when faced with restrictive signals, giving a braking curve based on the red signal ignoring all others instead of the current static speed control system which was very clever for 1984 but is prehistoric by current standards but still exceptionally reliable
    Thanks for the detailed explanation!


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  • #67
    Sam Russell
    Moderators, Science, Health & Environment Moderators Posts: 19,335 Mod ✭✭✭✭Sam Russell


    Irish Rail cannot be expected to upgrade their signaling systems just because there is an advance in technology. The Dart was designed and implemented in 1982 and uses technology that was OK for that time. The original Dart service was a two car train service every 15 or 20 mins, but now is an eight car service with a ten minute frequency in both directions.

    The gates at SP close 3 minutes before a NB and 2 mins before a SB, so they could be down for five minutes per ten minutes. If the service improves to 8 services per hour per direction, the level crossings will barely open. What will we do then?


  • #68
    CatInABox
    Moderators, Computer Games Moderators, Recreation & Hobbies Moderators Posts: 10,225 Mod ✭✭✭✭CatInABox


    Sam Russell wrote: »
    The gates at SP close 3 minutes before a NB and 2 mins before a SB, so they could be down for five minutes per ten minutes. If the service improves to 8 services per hour per direction, the level crossings will barely open. What will we do then?

    Indeed, Irish Rail have stated in their DART expansion plans that their eventual ambition is to increase the frequency of service to every 5 minutes. That's a minimum of 12 trains per hour per direction, not including any of the commuter trains either. If they don't remove the crossing before then, then the crossings simply won't open at all.


  • #69
    blobert
    Registered Users Posts: 1,495 ✭✭✭blobert


    goingnowhere wrote: »
    Line speed limit is 100kph and has been for 35 years and trains passing through Merrion Gates assuming they get clear signals (as is the design) should be at above 90kph)

    The rules on the DART are based on
    1. Level crossing must be CCTV inspected and are interlocked with the signaling system
    2. Full overlap protection is provided, so if gates are open, train is halted 200m from gates

    Elsewhere in the world (where the instances of level crossing accidents are much greater) the gates are timed to drop and be down 30 seconds before a train passes based on the fastest train


    For Merrion Gates the logic is

    Depart Blackrock, train gets a yellow signal which enforces a 50kph limit before Booterstown
    Loss of 30 seconds due the enforced speed limit due signals protecting Merrion Gates.
    Stops in Booterstown with a red signal.
    Doors open
    Merrion Gates are requested based on a timer
    Sydney Parade gates requested based on a timer
    Gates close and are confirmed closed by CCTV
    Signal clears to Yellow, next signals are Red (BN33), Red (BN31)
    Driver moves off
    Sydney Parade gates are confirmed closed by CCTV
    Signal clears to Green, next signals are Double Yellow (90kph), Yellow (50kph) this gives a profile where the permitted speed is greater than the braking curve
    DART even if it has past the first signal will pick up that the signal was retrospectively Green and give the driver 100kph
    Train arrives Sydney Parade with gates down and a yellow signal, the yellow signal is because Sandymount gates are not down
    Timer runs to call Sandymount gates
    Sandymount gates are confirmed closed by CCTV
    Train departs, the signal at Sydney Parade will move to double yellow (90kph)
    Next signal is yellow as Serpentine Ave gates are not closed, these trigger


    There is an upgrade to the DART ATP system coming which should allow DART trains to travel much faster when faced with restrictive signals, giving a braking curve based on the red signal ignoring all others instead of the current static speed control system which was very clever for 1984 but is prehistoric by current standards but still exceptionally reliable

    Thanks very much for the very detailed reply, I appreciate it.

    A lot of it is a bit too technical for me, just looking to understand it on a very basic level.

    I'm still somewhat in the dark as to how the signal to close the junction gates is given.

    For the DART you say when the DART is stopped in Booterstown (last station before Merrion Gates) the gates are requested "on a timer". Does this happen when it drives over the tracks there or some other system? If so are there 2 different systems that close the gates, one for DART and one for other trains.

    What I'm still hoping to get at is what it is that triggers the junctions closing and how possible it is to change that without massive effort, ie if a train driving over somthing at Booterstown station is what triggers the Merrion Gates closing can this in theory be moved.

    The fact that the line limit is 100kmph would very much tie in with my belief that that's a big cause of the problem as is, that the system is set up to be safe for 100kmph trains and hence the massive delay between barriers going down and train actually arriving.

    Again I'd agree that the closing of these junctions and building of a bridge as planned previously makes complete sense and I'll try to lobby to get this done. But I'm also aware of the level of slowness of anything being done on an infrastructure basis (ie we could be a long time waiting) so it might make sense to first do any quick fixes that are less work than building bridges/underpasses if they are possible.


  • #70
    goingnowhere
    Registered Users Posts: 4,131 ✭✭✭goingnowhere


    The trigger point for the gates is a function of the train type

    The trigger can either be a train passing a fixed point or a fixed time after it past a fixed point. The signalling system is split into sections so the borders between sections may not match with the optimum trigger points so a timer is used, based on last known position

    In the case of the DART area everything is scheduled by a computer based on the above triggers, the computer accounts for the need to ensure a minimum opening time for the gates as well as allowing only a single train in each direction per closure. Its non trivial.


  • #71
    trellheim
    Registered Users Posts: 5,854 ✭✭✭trellheim


    But I'm also aware of the level of slowness of anything being done on an infrastructure basis (ie we could be a long time waiting)

    ummm.... was it not the locals that kiboshed Merrion Gates programme last time ... its not the State or CIE/IR you are waiting on here


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  • #72
    MJohnston
    Registered Users Posts: 10,489 ✭✭✭✭MJohnston


    blobert wrote: »
    it might make sense to first do any quick fixes that are less work than building bridges/underpasses if they are possible.

    Buddy, I hate to tell you, but this right here is a big problem with your thinking. Reducing safety and efficiency of rail services would not be a fix. It'd be a cludge, a bad compromise. What you're proposing would be breakages - they'd make the system worse to benefit a tiny few at the expense of a large majority.

    I don't know why you would ever expect support for these proposals on a forum like this! You might be better off contacting the AA or some other car user lobby group.


  • #73
    machaseh
    Registered Users Posts: 777 ✭✭✭machaseh


    If you just go by train rather than by car, you won't have to wait at the level crossing !


  • #74
    blobert
    Registered Users Posts: 1,495 ✭✭✭blobert


    goingnowhere wrote: »
    The trigger point for the gates is a function of the train type

    The trigger can either be a train passing a fixed point or a fixed time after it past a fixed point. The signalling system is split into sections so the borders between sections may not match with the optimum trigger points so a timer is used, based on last known position

    In the case of the DART area everything is scheduled by a computer based on the above triggers, the computer accounts for the need to ensure a minimum opening time for the gates as well as allowing only a single train in each direction per closure. Its non trivial.

    Thanks very much for the reply on this.

    Its sounds as though the complex part of this is having all the variables working together, ie if you change somthing it does not break somthing else.

    But would I be correct in saying if you were to make changes to it the main expense would be moving the fixed point signals, ie the timer changes would just be a chase of changing somthing from 60 to 30 seconds on the system?

    While it might be non trivial to do in terms of the level of complication, I'm guessing the actual cost in €€€ terms would be very low, certainly vs the cost of building tunnels under junctions?


  • #75
    cdaly_
    Registered Users Posts: 6,440 ✭✭✭cdaly_


    CatInABox wrote: »
    Indeed, Irish Rail have stated in their DART expansion plans that their eventual ambition is to increase the frequency of service to every 5 minutes. That's a minimum of 12 trains per hour per direction, not including any of the commuter trains either. If they don't remove the crossing before then, then the crossings simply won't open at all.
    blobert wrote: »
    Thanks very much for the reply on this.

    Its sounds as though the complex part of this is having all the variables working together, ie if you change somthing it does not break somthing else.

    But would I be correct in saying if you were to make changes to it the main expense would be moving the fixed point signals, ie the timer changes would just be a chase of changing somthing from 60 to 30 seconds on the system?

    While it might be non trivial to do in terms of the level of complication, I'm guessing the actual cost in €€€ terms would be very low, certainly vs the cost of building tunnels under junctions?
    See CatInABox's reply above...


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