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PC Lirr M7-different Speed Limits Atcvshud

Discussion in 'Technical Reports' started by m.poznan, Sep 12, 2020.

  1. m.poznan

    m.poznan Member

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    Dont know if its a bug, but running my first service today, and decided to run with all saftey sytems enabled.
    With ATC enabled the speeds on the HUD and on the ATC dont match, either they are higher on the HUD or on the ATC or the other way around. Could it be a bug, or just my poor understanding of the ATC system?

    In the picture below its visible that the HUD states a higher speed then the ATC, and going over 16MPH will trigger an emergency stop!

    Untitled.png
     
  2. matjamca

    matjamca Well-Known Member

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    The safety system and track speeds will vary. You have to follow the lowest speed, whether that’s on the safety system or the HUD.

    In your picture, the safety system is telling you to do 15mph regardless of track speed. That’s the speed you must follow or you will get the emergency brakes applied.
     
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  3. m.poznan

    m.poznan Member

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    Yeah, i do get that, but, in the drive, there was a reversed instance, where the saftey systems permitted a higher speed then the HUD, so in that case, do i follow the ATC or the HUD, i know that there are instances whith PZB where the speed commanded by PZB will be lower then HUD, but i thought that ATC worked differently?

    Also with ATC speeds, there is absolutley no way to make stations on time, not even remotley, so that has me wondering as well.
     
  4. matjamca

    matjamca Well-Known Member

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    If the ATC gives a higher speed than the track speed, you should follow the track speed.
     
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  5. paul.pavlinovich

    paul.pavlinovich Member

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  6. m.poznan

    m.poznan Member

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    I mean, it could be, on the other hand, driving with PZB you can also get a similar scenario where the PZB commands a lower then track speed.. Im really not that good with the saftey systems to be able to tell if it really is a bug or just the way its ment to be!
     
  7. matjamca

    matjamca Well-Known Member

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    It’s not a bug. You always drive at the lowest speed. ATC or Track.
     
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  8. Dinosbacsi

    Dinosbacsi Well-Known Member

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    It is not a bug, that is how ATC on the LIRR works. There is a track speed limit and an ATC speed limit, and you always follow whichever is the lowest in the given situation.
     
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  9. ZeenozPlays

    ZeenozPlays Well-Known Member

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    As everyone else has said, it’s not a bug. That’s how the ATC works, it works independently from the track speed, meaning, the ATC can show a 40 MPH Limit, while track speed is 15 or vice versa. The ATC relies solely on the signals.
     
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  10. ixofxiii

    ixofxiii Active Member

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    I also agree. It's not a bug. Welcome to ATC on the LIRR. Here's the best bet:
    Always go the lower speed of the two. Get a feel for what limits are where.
     
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  11. m.poznan

    m.poznan Member

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    Thank you to all of you for the comments, ill surely try to play by the book, and listen to ATC :D
     
  12. Noah Berger

    Noah Berger New Member

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    You are in Km/h... The Trains Screen is in MPH...
     
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  13. Rudolf

    Rudolf Well-Known Member

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    ACT and speed limits at LIRR form a weird combination. I really do not understand the way US engineers designed this, assuming the implementation in TSW is correct. It is as mad as allowing trains longer than platform length to stop at some of the short platforms. Not sure if this is realistic as well. You would net expect this at abuy line, or maybe the guard will keep those doors closed somehow?
     
  14. ZeenozPlays

    ZeenozPlays Well-Known Member

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    It is realistic, the conductor just wouldn’t open the doors that are out of the platform.
     
  15. cwf.green

    cwf.green Member

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    Speed you follow = min{ATC Speed, Track Speed}
     
  16. malikrthr

    malikrthr Well-Known Member

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    Yes, similar to Metro North, there is a track speed limit and signal speed limit. With ATC Active (Automatic Train Control) you follow the lower speed between signal speed and track speed. Your signal speed limit will be shown on the in cab display. If the train travels above the indicated in cab signal speed, the alerter will sound. If the alerter is not acknowledged within a few seconds, the train's emergency brakes will be activated.
     
    Last edited: Sep 17, 2020
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