PC Ntp Class 47 Braking Is Erratic And Not Correct.

Discussion in 'Technical Reports' started by ghawk2005, Jan 14, 2021.

  1. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    The Class 47 (and Class 45 too) train brake does not behave correctly at all. When you click initial setting it goes sometimes to 21psi, sometimes 33, and sometimes 40. It is all over the place. Then after you apply initial, and progress it a bit further the needle ends up way off the gauge. The Class 47 in the West Somerset Railway seems to behave correctly, but not the North Transpennines version. This needs to be thoroughly investigated and tested properly because I am not the only one who has noticed this disaster!!

    Does anyone else find this ?
     
  2. DominusEdwardius

    DominusEdwardius Well-Known Member

    Joined:
    Dec 8, 2016
    Messages:
    198
    Likes Received:
    251
    You are more than likely misusing the air brake, what has probably happened is you have put the brake handle into the release position and overcharged the brakepipe then applied it within about 4 minutes of using the release position. When you overcharge the brakes and do not let the overcharge bleed off they will apply much more harshly than they're supposed to.

    For example making an initial application will always drop the brake pipe to around 66psi, with the brake overcharged to say 75psi this is an approximate 9psi pressure reduction to the initial application pressure of 66psi. This is the equivalent of dropping the brake pipe normally from 72psi to 63psi, which is almost a 50% application of the brake! More to the point to get the brake off again you will have to increase the brake pipe back above 75psi to get it off again.

    The release position should not be used at all except to release a suspected sticking brake, since this is very unlikely unless you've previously misused it by applying when an overcharged you shouldn't ever use the position really. If you do accidentally or otherwise use the position you must leave about 4 minutes before reapplying the brake.

    The reason this does not occur on the WSR Class 47 is simple, it is operating with vacuum brakes. When operating on vacuum brakes the above does not apply as the air braked portion of the locomotives brake distributor is being rendered inoperative and so release position can be used freely (which is used to speed up the locomotives brake exhausters). The same is true for the NTP 47 and 45 if operating on vacuum brakes.
     
    • Like Like x 2
    • Helpful Helpful x 2
  3. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    This makes sense, and I have considered this may be the case, and I would believe you IF when selecting ‘Running’ it did actually release the brakes but it doesn’t. It pulls it back to about 19psi. (As far as I understand it, ‘Running” should reduce the pressure to almost 0psi so the brakes are effectively release yes? This doesn’t happen.... I don’t think. I will for sure try it again so thanks for the suggestion.
    Will report back later.

    Cheers
    Gary
     
  4. Lamplight

    Lamplight Well-Known Member

    Joined:
    Aug 20, 2020
    Messages:
    2,327
    Likes Received:
    3,744
    Running doesn‘t release the brakes if you overcharged them before (and didn‘t wait fir it to bleed off).
     
  5. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    I have tried it again, and it works perfectly providing you never use the release or overcharge option. I accidently did it and once I did it was game over. The brakes stuck on 4-6psi, the initial application was crazy again and despite waiting for 10 minutes it never went back to normal.

    I did see a Fix in the Roadmap about the 47 brakes being stuck on and it was due to be worked on, so maybe it was that ?
     
  6. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    Waited ages and it never returned to ‘before using overcharge’
     

    Attached Files:

  7. Lamplight

    Lamplight Well-Known Member

    Joined:
    Aug 20, 2020
    Messages:
    2,327
    Likes Received:
    3,744
    Just to make sure it‘s not user error: You have to release the brakes using overcharge (after they were overcharged) until the brake cylinder is empty. Then, you have to wait until the brake pipe pressure has returned to normal levels. In the situation of your screenshot (as far as I can tell from a single screenshot), the brakes won‘t ever fully release again until you follow these instructions.
     
  8. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    Yes I have tried that many times to no success. After releasing, I wait, and all that happens is the brakes creep back on again to 4-6psi and the behaviour never returns to normal.
     
  9. Lamplight

    Lamplight Well-Known Member

    Joined:
    Aug 20, 2020
    Messages:
    2,327
    Likes Received:
    3,744
    One last question: Do you hold release/overcharge for an extended amount of time, or do you put it in release/overcharge and immediatly return the handle to running?
     
  10. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    Tried both holding for a while, Then just flicking it in briefly.

    Tried again, released as instructed, then just waited .... the lowest the BP gauge got was 73, down from 77, then brakes still stick back on again even without me doing anything.
    Is there a compressor or blower I need to turn on or something ?
     
  11. Lamplight

    Lamplight Well-Known Member

    Joined:
    Aug 20, 2020
    Messages:
    2,327
    Likes Received:
    3,744
    I don‘t think so.
    It does appear to be a bug then. I‘m sorry if this felt a bit like an interrogation, but I wanted to make sure it‘s not a user error since many people have problems using overcharged brakes correctly. Thanks for your input.
     
  12. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    No, it was very insightful and I really appreciate your kind input. I have certainly learnt something today, but yes unfortunately it does seem to be a bug. I even tried shutting down the whole loco and restarting etc. Nothing has worked other than exiting the game

    I really hope DTG sort this soon.
     
  13. DominusEdwardius

    DominusEdwardius Well-Known Member

    Joined:
    Dec 8, 2016
    Messages:
    198
    Likes Received:
    251
    Ah yes the 47 does currently knacker itself if you use the release position at all, that one is scheduled for a fix. In the mean time just try to avoid at all costs using the release position even briefly.
     
  14. KiwiLE

    KiwiLE Well-Known Member

    Joined:
    Jul 27, 2018
    Messages:
    330
    Likes Received:
    445
    I remember having to hold the (air) train brake in overcharge for a minute IRL...Is that modelled Dom?
     
    Last edited: Jan 15, 2021
  15. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    Ohh that’s interesting. I will try that just for curiosity. Thanks
     
  16. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    Nope - doesn't work. Tried it several times.

    I have also tested the Class 31, 37, 33 and all have similar braking systems as far as I understand? They all work as expected and fine from what I have witnessed. It is only the Class 47 and Class 45 that have the issue. Definitely a bug!!
     
    • Like Like x 2
    • Helpful Helpful x 1
  17. DTG Natster

    DTG Natster Producer Staff Member

    Joined:
    Sep 2, 2020
    Messages:
    1,554
    Likes Received:
    10,948
    This is a known issue and we have a fix. We are aiming to release asap, ideally for the next update however that's not certain.
     
    • Like Like x 2
  18. squerble

    squerble New Member

    Joined:
    Mar 8, 2020
    Messages:
    10
    Likes Received:
    18
    Any chance I can bump and ask why the fix hasn't been released yet? Hit this problem myself yesterday so it's disappointing to see the fix was ready nearly a year ago but still hasn't found its way in :(
     
  19. Clumsy Pacer

    Clumsy Pacer Well-Known Member

    Joined:
    Dec 10, 2016
    Messages:
    2,920
    Likes Received:
    3,895
    I've just tested it and it seems to be fine. Putting the brake just into running releases it, and putting it into release/overcharge, the BP gradually fell to 73 (not 72), but briefly putting it in first application then putting it in running has fixed that and it was back to 72. Didn't find the brakes creeping on either.
     
  20. ghawk2005

    ghawk2005 Well-Known Member

    Joined:
    Nov 20, 2020
    Messages:
    415
    Likes Received:
    795
    I posted this ages ago and since then I have found that yes ‘running’ works fine. Release/overcharge makes it go loopy
     

Share This Page