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Coupler Physics

Discussion in 'Suggestions' started by Ben_Broomfield, Jun 13, 2019.

  1. Ben_Broomfield

    Ben_Broomfield Active Member

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    Hiya guys,

    One small tiny detail i wish was here is coupler physics - where the train/wagon/carriage coupler adapts to the load depending on gradient etc. By that i mean how the coupler acts, gathers the slack & makes it tight or has no slack on it and is loose.

    To make it more visually easier to understand i have the Class 40 heading out of Manchester with around 10 100T TEA Oil Tanks for Leeds. The gradient is around 1:50 out of Manchester which should put some strain on the consist.

    [​IMG]

    As you can see the wagons are not showing any weight physics - if there was, the coupler would be tight & taking on the strain of the load as the train goes up the gradient.

    I know its a small detail but that personally would make it more realistic & give a larger sense of the weight your train is pulling.

    Let me know what you think!

    Cheers guys :)
     
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  2. Anthony Pecoraro

    Anthony Pecoraro Well-Known Member

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    The American trains simulate slack.
     
  3. nne4229

    nne4229 Well-Known Member

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    Anthony what's with your replies all the time. You always have to say something that's way too basic or irrevilant/way too besides the point.
     
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  4. some1

    some1 New Member

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    I wonder if that's something on the roadmap somewhere, or did they just give up after initial implementation in CSX?

    Does anyone have any up to date info?
     
  5. Factor41

    Factor41 Well-Known Member

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    Anthony's point above is valid - if you nail the power or brake heavily on a loaded F40PH-2CAT on Peninsula Corridor, you can feel the ripple of momentum as the trucks pull against the slack, pick up speed and bump back into the loco, which I guess is exactly what the OP was looking for. If they can do it on the US routes, surely they can do it on any?
     
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  6. Anthony Pecoraro

    Anthony Pecoraro Well-Known Member

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    Headsway makes it more noticeable too.
     
  7. loader.tom

    loader.tom Member

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    That's a good point, and I thought about this whilst playing Main Spessart Bahn yesterday, whilst banking, it's great when the buffers compress. but the screw link coupler on the bogie tanks are the complete opposite than the OP's screenshot, they are always tense regardless of braking or taking power...etc
     
  8. Anthony Pecoraro

    Anthony Pecoraro Well-Known Member

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    I think it’s like that irl. I don’t know much about European trains, but I think they tighten the couplers so that that don’t move. On the UK freight trains in TSW, you do notice the slack too.
     
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  9. thearkerportian

    thearkerportian Well-Known Member

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    That's fairly close to the truth. You wouldn't want every single wagon to bump into one in front when the brakes are applied up front. After all, air pressure is coming from the (lead) loco, and needs a bit of time to work its way along the length of train, meaning that the forward cars start braking earlier than those further back.
     
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  10. loader.tom

    loader.tom Member

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    Of course, they'll be tightened up to some extent, but there's definitely still movement within the screw link. I just tried on the game now with a rake of bogie tanks, even setting back on the wagons, the coupling shouldn't be that ridged, there should be some (not a lot) movement still.
     
  11. Anthony Pecoraro

    Anthony Pecoraro Well-Known Member

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    Have you tried it on the BR Heavy Freight Pack?
     
  12. loader.tom

    loader.tom Member

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    Unfortunately not, other than GWR, the only British route I have is the Transpennine route which I got Saturday, I'll give that a go later today.
     
  13. Digital Draftsman

    Digital Draftsman Well-Known Member

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    Of course the coupling in the above image is wrong anyway as the locomotive screw-link coupling should be used, not the instanter coupling of the wagon. This is stated in the BR General Appendix of the time.
     
  14. synthetic.angel

    synthetic.angel Well-Known Member

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    I was quite surprised to see your picture. I had some very minor (and I really do mean very very minor) issues with some of the buffer and coupler physics/animations that I have seen/noticed, but this looks like a solid connection between a pair of container flats.... or the link in the middle might weigh about 1500 tonnes...? I had to check this out for myself, and was quite shocked to reproduce it for myself.

    This is poor. It simply isn't a simulation, in my opinion. And I am sure I have seen this kind of stuff modelled in simulations over ten years ago....? Isn't this really very basic stuff? You might see this in an early beta, but surely not a released product...? And released at an additional premium price...?

    Anyway - on a more positive note - check out the Clas 31 on TVL. I think you'll find the full physics in operation, as you would expect, on the train (including COG), the buffers, and the coupling (with the cement wagons, for example). I really wish DTG would apply some common standards to their products (or insist on a minimum standard, if developed by a 2nd party).
     
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  15. loader.tom

    loader.tom Member

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    I remembered someone saying CSX had coupler slack implemented, so for the first time I loaded it up and had a look. The physics are definitely better, 100%. However, when pulling away, the slack visually pulls the couplers out of place as seen below.

    When braking
    530070_20200122191437_1.png
    When pulling away.
    530070_20200122191407_1.png
     
  16. steadfast

    steadfast Member

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    3 turns of the coupling should be showing either side on a screw link. Too loose the wagons will snatch and there's a risk the coupling will jump off. Too tight and theres a risk of buffer lock, derailment or personal injury. With buffers touching on straight track, the coupling will sag slightly. With the coupling under tension, the buffer gap is an inch or two.
    Continental wagons have longer buffers, but the upper link on the coupling is longer too so three turns is still sufficient.
     
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  17. Trim

    Trim Active Member

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    The visual representation of three-link couplings in Northern Transpennine is certainly wrong, Here is a picture of the coupling between the second and third TEA 100-ton bogie tank wagons in an 18-wagon train pulling up Miles Platting bank:
    upload_2020-2-8_12-12-5.jpeg

    Here is the same coupling descending through Marsden. Just to make sure the couplings were compressed, I released the train brakes and applied full engine brakes (which admittedly are pretty useless on a class 40):
    upload_2020-2-8_12-16-41.jpeg

    However, although the visuals are wrong, the jolt you get in the cab seems spot on to me. The jerk is noticeably worse with longer and heavier trains, and is almost unnoticable with passenger trains which have buckeyes between coaches (although the coupling to the engine is a screw link).

    Personally, I am much more concerned with the feel of how the trains drive and the correct simuiation of railway operating practices, and am willing to put up with a whole load of graphical errors (provided signals are displayed correctly). However, I can understand why some people might not be happy with this, particularly if it is rendered correctly on other routes. For what it's worth, the VVV 12-ton ventilated van couplings in NTP are depicted exactly the same as the TEAs.
     
    Last edited: Feb 9, 2020
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  18. steadfast

    steadfast Member

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    In case anyone is unsure how they look, here's how a screw coupling that is slack should look. 3 turns either side, buffers compressed.
    IMG_20200209_122325_copy_2080x1560.jpg
    As the train pulls forward, the coupling goes tight. When stopping normally the coupling will be tight due to the wagons having greater brake force than the loco. However, if the driver uses some straight air loco brake to help stop, it normally bunches up and goes slack like the photo. You also need it slack to couple or uncouple
     
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