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What signalization system does luas use?

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  • 28-08-2017 5:00pm
    #1
    godtabh
    Moderators, Science, Health & Environment Moderators Posts: 23,204 Mod ✭✭✭✭


    I have an issue with the signalization of a luas crossing.

    Something has changed such that I could be sitting at a light for up to 5 mins waiting for two Luases to pass.

    I'd like to know how the Luas signal works so I can raise my concerns with TII.


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    #2
    cherryghost
    Moderators, Technology & Internet Moderators Posts: 17,133 Mod ✭✭✭✭cherryghost


    Where did you get stuck?


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    #3
    godtabh
    Moderators, Science, Health & Environment Moderators Posts: 23,204 Mod ✭✭✭✭godtabh


    I'd rather not give the location but its on the Green Line near Brides Glen


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    #4
    Ben D Bus
    Registered Users Posts: 2,114 ✭✭✭Ben D Bus


    godtabh wrote: »
    I'd rather not give the location but its on the Green Line near Brides Glen

    I don't think anyone will be able to identify you based on where you cross the Luas line!


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    #5
    godtabh
    Moderators, Science, Health & Environment Moderators Posts: 23,204 Mod ✭✭✭✭godtabh


    Where the crossing is has nothing to do with the question asked. I could have said at stillorgan.


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    #6
    LXFlyer
    Registered Users Posts: 17,562 ✭✭✭✭LXFlyer


    Ben D Bus wrote: »
    I don't think anyone will be able to identify you based on where you cross the Luas line!

    It has to be at Laughanstown - that's the only crossing near Brides Glen, which to be fair, would have near single figure cars crossing it each day.

    It could be a technical fault OP - get in touch with TII.


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    #7
    Pelvis
    Closed Accounts Posts: 1,758 ✭✭✭Pelvis


    Not sure what you expect to achieve, they're not going to change the signalling system for you. I had the same issue on a bus commute once that involved crossing a dart line, was a monumental pain in the balls. But if the choice is between slowing down a few hundred people in a luas/dart compared to a few dozen in cars, then the choice is obvious.


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    #8
    LXFlyer
    Registered Users Posts: 17,562 ✭✭✭✭LXFlyer


    godtabh wrote: »
    Where the crossing is has nothing to do with the question asked. I could have said at stillorgan.

    Hardly a need for a state secret style approach though?

    The location could have everything to do with it - line of sight or other issues.


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    #9
    godtabh
    Moderators, Science, Health & Environment Moderators Posts: 23,204 Mod ✭✭✭✭godtabh


    Again my question is what system is used. The crossing location or what I hope to achieve isn't really relevant


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    #10
    LXFlyer
    Registered Users Posts: 17,562 ✭✭✭✭LXFlyer


    godtabh wrote: »
    Again my question is what system is used. The crossing location or what I hope to achieve isn't really relevant

    Again - the location could everything to do with it.


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    #11
    CramCycle
    Moderators, Sports Moderators Posts: 24,515 Mod ✭✭✭✭CramCycle


    Is your issue that you think it does not need to be a red light for the full time? 5 minutes seems long but there maybe no choice. I would just contact them to query it. Maybe ask if they can check is there a signal fault as the light does not allow crossing even though you have times a 5 minute gap between crossing LUASs.
    They will either fix it or say that for safety reasons there is nothing you can do. After that your best option is too leave 5 minutes earlier.


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    #12
    godtabh
    Moderators, Science, Health & Environment Moderators Posts: 23,204 Mod ✭✭✭✭godtabh


    CramCycle wrote: »
    Is your issue that you think it does not need to be a red light for the full time? 5 minutes seems long but there maybe no choice. I would just contact them to query it. Maybe ask if they can check is there a signal fault as the light does not allow crossing even though you have times a 5 minute gap between crossing LUASs.
    They will either fix it or say that for safety reasons there is nothing you can do. After that your best option is too leave 5 minutes earlier.


    More or less. It appears that one arm of the junction is held back longer than it should be. Straight stretch of track so I don't think safety is an issue.

    A similar situation in road lights could easily be spec'd away


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    #13
    MrMorooka
    Registered Users Posts: 710 ✭✭✭MrMorooka


    It's probably just a track circuit. So you have to wait for the trams to leave the section and the circuit to clear before the lights can change. Presumably they could change the position of the circuit so the section is shorter or something.


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    #14
    jimmycrackcorm
    Registered Users Posts: 14,330 ✭✭✭✭jimmycrackcorm


    godtabh wrote:
    Something has changed such that I could be sitting at a light for up to 5 mins waiting for two Luases to pass.

    What makes you think it is the LUAS signal that is at fault, and not the timings on the traffic lights?


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    #15
    Cordell
    Registered Users Posts: 5,840 ✭✭✭Cordell


    I'd like to know how the Luas signal works so I can raise my concerns with TII.
    Luas passes through the administrative areas of Dublin City Council, South Dublin County Council and Dún Laoghaire Rathdown County Council. At signal controlled road junctions the Automatic Vehicle Locator System (AVLS) interfaces with the road traffic controller to afford a level of priority to the trams

    AVLS usually means a receiver in between the tracks and a transponder on the undercarriage of the tram - if nothing changed dramatically in the last 15 years or so. Normally it will be one ahead of the junction to ensure safe green light, and one after the tram clears the junction. Of course, particulars of the junctions will dictate the details of the solution. Track circuits are usually instaled for point switch safety only.


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    #16
    L1011
    Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 67,854 Mod ✭✭✭✭L1011


    If it is a quiet junction and you're left waiting; its more likely that you're not hitting the vehicle detection loop properly than anything else.


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    #17
    LXFlyer
    Registered Users Posts: 17,562 ✭✭✭✭LXFlyer


    godtabh wrote: »
    More or less. It appears that one arm of the junction is held back longer than it should be. Straight stretch of track so I don't think safety is an issue.

    A similar situation in road lights could easily be spec'd away

    So we are talking somewhere presumably along Ballyogan Road given the reference to "the arm of the junction".

    The fact that there is a junction at the crossing is relevant - you didn't say that in your original post.

    As someone else has stated it could well be a traffic signal issue rather than the LUAS signalling system.

    I really fail to see the need to be so cloak and dagger about this.


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    #18
    Victor
    Registered Users Posts: 78,290 ✭✭✭✭Victor


    My initial suspicion is that the induction loop on the road isn't being triggered. There is also the possibility that is is only set to trigger when X number of cars are queuing.

    https://en.wikipedia.org/wiki/Induction_loop
    MrMorooka wrote: »
    It's probably just a track circuit. So you have to wait for the trams to leave the section and the circuit to clear before the lights can change. Presumably they could change the position of the circuit so the section is shorter or something.
    This seems to make sense as their RTPI is quite coarse and signalling based, not GPS based.
    jimmycrackcorm wrote: »
    What makes you think it is the LUAS signal that is at fault, and not the timings on the traffic lights?
    The traffic lights are run by the signalling system, which is probably tied to SCATS, but not for standalone junctions. I don't know how accurate the map is.

    https://en.wikipedia.org/wiki/Sydney_Coordinated_Adaptive_Traffic_System
    http://www.dublindashboard.ie/dublindashboard/ScatsMap.html


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    #19
    HonalD
    Closed Accounts Posts: 1,288 ✭✭✭HonalD


    godtabh wrote: »
    I have an issue with the signalization of a luas crossing.

    Something has changed such that I could be sitting at a light for up to 5 mins waiting for two Luases to pass.

    I'd like to know how the Luas signal works so I can raise my concerns with TII.

    OP, talk to TII or DLRCC and they'll be glad to check out if there is a fault.

    I would though suggest that your estimate of "up to 5 mins" is not accurate. Human behaviour would suggest that, in general, a wait of 300 seconds would not be tolerated by motorists. The temptation to either a) cross the tracks without a green light or b) be so pissed off that you ring TII immediately (rather than post on boards.ie) would kick in before you had accurately determined that the wait was 5 minutes. Also, if it happened again, you'd be less likely to wait....and so on and so on......

    But you are the only person who can speak on the delay as I am just surmising. ;)


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    #20
    Jamie2k9
    Registered Users Posts: 10,673 ✭✭✭✭Jamie2k9


    Really can't see it been a fault, lots of quiet junctions will hold traffic when trams are approaching where as the busier ones will only hold traffic if a tram is almost at the signal. You see it in town where an outbound tram will have been cleared with an inbound maybe 10 seconds sway from the same junction and getting held but the opposite quiet ones.

    Up to 5 minutes is probably 3 minutes in reality unless the OP has timed it exactly which is pretty normal.


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    #21
    godtabh
    Moderators, Science, Health & Environment Moderators Posts: 23,204 Mod ✭✭✭✭godtabh


    For what it's worth I met with TII yesterday professional on a different matter. I have their full specs now.


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    #22
    Dardania
    Registered Users Posts: 3,612 ✭✭✭Dardania


    godtabh wrote: »
    For what it's worth I met with TII yesterday professional on a different matter. I have their full specs now.
    Care to share some details?


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    #23
    godtabh
    Moderators, Science, Health & Environment Moderators Posts: 23,204 Mod ✭✭✭✭godtabh


    I haven't read it yet


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