Overhead Neutral Sections

Discussion in 'General Discussion' started by esgtee, Oct 14, 2020.

  1. esgtee

    esgtee Member

    Joined:
    Jul 20, 2020
    Messages:
    23
    Likes Received:
    34
    So when sim driving through neutral sections, I power off with pantograph raised like I was trained to on the WCML. But are there different standard ways (other lines or other countries) like lowering pantographs or powering through them with some automatic power cut-off?

    guardupfront
    This sounds like a railway pub quiz question. Which station on lines out of Waterloo has 25kv ac overhead? First I was thinking Wimbledon because of Croydon Tramlink, but that is 750dc overhead. Wracking my brain, and came up with... Reading?
     
  2. guardupfront

    guardupfront Active Member

    Joined:
    Jun 25, 2020
    Messages:
    169
    Likes Received:
    130
    Nailed it in one!
     
  3. brummie

    brummie Active Member

    Joined:
    Mar 18, 2018
    Messages:
    169
    Likes Received:
    57
    I would think they would do the same. Lowering then raising a pantograph for a neutral section would take a bit of time, and at speed would need meticulous timing. Much easier just to slip controller into neutral as lm sure you would agree.
    I think powering through them may cause a slight jolt, don't know really.
     
  4. guardupfront

    guardupfront Active Member

    Joined:
    Jun 25, 2020
    Messages:
    169
    Likes Received:
    130
    For DC there’s no actual requirement to stop taking power over gaps, but the professional driving policies of DC TOCs (mine included) make reference to reducing power to avoid jolts and surges when your train gets back on the third rail again.
    My main AC issue is that it’s significantly harder (AFAIK) to short circuit in an emergency than DC is, but the actual driving over the two is pretty much the same
     
  5. brummie

    brummie Active Member

    Joined:
    Mar 18, 2018
    Messages:
    169
    Likes Received:
    57
    Interesting. I think l might try that then, reduce power setting instead of going into neutral.
     
  6. 749006

    749006 Well-Known Member

    Joined:
    Dec 10, 2016
    Messages:
    8,420
    Likes Received:
    2,675
    In the UK when you go thru a Neutral Section there are track magnets on the sleeper ends either side
    The magnets trip the Automatic Power Cutoff - APC and the main breaker then reset without any action from the driver.
    It is modelled on a few routes such as WCML over Shap where the Class 87 has to be run down before the Neutral sections

    In Europe it is all at the Drivers command -
    At some places it is just necessary to shut off and open the breaker - other places the Panto must be lowered.
     
    • Like Like x 1
  7. brummie

    brummie Active Member

    Joined:
    Mar 18, 2018
    Messages:
    169
    Likes Received:
    57
    Hi Peter,
    Thats intetesting what you say. For simming purposes, what do you normally do when going over neutral sections, for example the class 350?
     
  8. esgtee

    esgtee Member

    Joined:
    Jul 20, 2020
    Messages:
    23
    Likes Received:
    34
    Yeah, I'm told powering through could make a jolt, but the main reason we're told to power off is to stop any arcing from wire to pantograph. This can chip the carbon strip on the pan, or worse cause damage like an air leak (compressed air is what raises it).

    For AC there are DEPs, for Network Rail specialists to earth it (I'm told) with big long poles. Is DC with that wooden bar thing?

    Now the 87 seems really weird to me. Tapping the transformer gradually, running up, running down, stepping down. I guess that's why you have the black neutral warning board. Back then with locos took some time to shut off power, these days it's 1 second to move the power/brake controller.
     
    Last edited: Oct 15, 2020
    • Like Like x 1
  9. Clumsy Pacer

    Clumsy Pacer Well-Known Member

    Joined:
    Dec 10, 2016
    Messages:
    2,956
    Likes Received:
    3,934
    Why would you need to short out OHLE in an emergency?
     
  10. esgtee

    esgtee Member

    Joined:
    Jul 20, 2020
    Messages:
    23
    Likes Received:
    34
    If the 3rd rail is accidentally re-energised, a short circuit to the -ve return path of the DC system causes the circuit-breakers at the substation to trip immediately, protecting personnel at a worksite or emergency scene. With overhead line isolation, they switch off the current first, but there's a residual voltage to get rid of. This is earthed to the running rail via specific catenary gantries, by using giant crocodile clips held on poles :D

    If you've got an emergency, and passengers have to be evacuated, you don't want 750Vdc or for that matter 25kVac to cook your customers!!!
     
    • Like Like x 2
  11. guardupfront

    guardupfront Active Member

    Joined:
    Jun 25, 2020
    Messages:
    169
    Likes Received:
    130
    sure is, the mighty Short Circuit Bar!

    25kV AC on a broken/dropped wire can arc up to 9 feet through the air to electrocute a person; I wouldn’t want to be doing an evacuation/examination of the line in the dark with the possibility of that happening. A poor VT crew many years back experienced that.
     
  12. 749006

    749006 Well-Known Member

    Joined:
    Dec 10, 2016
    Messages:
    8,420
    Likes Received:
    2,675
    Nothing :D
    If it is built in to the loco/unit I obviously use it but for a train without that system I don't bother.

    I have a CFR Route and I forgot about a Neutral Section and the systems said "Game Over"
    Must change that Scenario
     
  13. brummie

    brummie Active Member

    Joined:
    Mar 18, 2018
    Messages:
    169
    Likes Received:
    57
    I bet you were near to the end when you got the dreaded "Game Over" :D:D
     
    • Like Like x 1
  14. inversnecky

    inversnecky Well-Known Member

    Joined:
    Dec 26, 2020
    Messages:
    2,252
    Likes Received:
    841
    I’m just starting with 86s on WCML Shap.

    Is it the case, then, that not all the 25kV lines on TS routes have labelled Neutral Sections?

    Or if they do, it’s not ‘working’ like in the Shap route?

    Or is it more the case that it’s the trains used that have to have the scripting to recognise an NS and act accordingly?

    If the latter, then, they’d work everywhere with identified NSs?
     
  15. 749006

    749006 Well-Known Member

    Joined:
    Dec 10, 2016
    Messages:
    8,420
    Likes Received:
    2,675
    The working OHLE was only introduced with WCML over Shap and DTG have placed it in the WCML South route
    It is a Track Linked object and is unrelated to the actual Magnets you see
    Even if you see the Lineside signs the Neutral Section might not work - like on WCML North or on the ECML routes

    It is dependant on the loco/unit having the scripting and the track having the actuator

    Older locos like the original Class 86 and 87 do not see the magnets
    The Class 87 and possibly the Class 86 from WCML over Shap do see the Magnets
    The Class 86 AP Pack also sees the Magnets

    Most if not all Emus don't see the Magnets
     
    • Like Like x 1
  16. Clumsy Pacer

    Clumsy Pacer Well-Known Member

    Joined:
    Dec 10, 2016
    Messages:
    2,956
    Likes Received:
    3,934
    Ihe Class 350 from WCML Trent Valley has neutral section functionality, as does the Class 91 with the AP Enhancement Pack. Not sure if the 390 in WCML south does but I imagine it does.
     
  17. inversnecky

    inversnecky Well-Known Member

    Joined:
    Dec 26, 2020
    Messages:
    2,252
    Likes Received:
    841
    Thanks. I’ve still to explore much of these other routes. Do there’s no real way to know if the other route NLs work, without trying, I guess..
     
  18. atomicdanny

    atomicdanny Staff Member

    Joined:
    Mar 14, 2017
    Messages:
    391
    Likes Received:
    353
    The 390 and 350 in the WCML South route both work with Neutral sections (the WCML - South 350 is not based on the Trent Valley one - before someone says it :) )
     
    • Like Like x 1

Share This Page