Wheel Slip In Tsw Feels Very Predictable/simplified?

Discussion in 'Train Sim World Discussion' started by londonmidland, Nov 16, 2022.

  1. londonmidland

    londonmidland Well-Known Member

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    I'd like to ask, has wheel slip been set up in a realistic way in TSW, or is it just the same generic value for all trains?

    I ask because when driving the Electrostar, which is notorious for slipping in real life, even at slow speeds, it seems like in TSW it has just been set up to slip based on the notch/power you apply. In real life I believe the onboard computers will individually control each axle to prevent slipping.

    So, a common theme I seem to encounter with the Electrostar during poor adhesion when driving it in TSW:
    - Depart in notch 1: Never have issues with wheel slip
    - Depart in notch 2: Never have issues with wheel slip
    - Depart in notch 3: ALWAYS experience wheel slip
    - Depart in notch 4: ALWAYS experience wheel slip

    So it seems like it has been set up to simply just react to the notch you depart in, as opposed to having any sort of variable, based on track conditions. Also, to recover from wheel slip, all I have to do is notch down and it IMMEDIATLY stops and accelerates normally.

    Similarly, when braking, I rarely have any issues slowing the Electrostar down. Even when braking harshly, there's little to no wheel slide/wheels locking up. Its almost like the wheels are glued to the tracks, with perfect adhesion.

    So I'd like to ask, is this just a case of Simugraph not being set up advanced enough for the Electrostar when it comes to wheel slip and slide?
     
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  2. graham.haddon

    graham.haddon Active Member

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    Some locomotives/units seem better than others in the wheel slip simulation department. For instance the 465/9 is very good.
    But I don't really know how it works in the more simplified and/or older units. I know track conditions play a big role in how easily locomotives slip.
     
  3. rennekton#1349

    rennekton#1349 Well-Known Member

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    Wheel slip does feel predictable in tsw for each of the trains. You have to reach a certain speed to go to higher notches to not get wheelslip. Some have no wheelslip at all even in adverse weather. Some only have wheelslip when braking harshly in rainy weather.
     
  4. arek#2842

    arek#2842 Well-Known Member

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    Yep, wheelslip never caused me any trouble when driving any passenger train. All you need to remember is not to start from too high notch and not to break too harsh when approaching the stop.

    Can't tell about freight trains though as I'm not driving many of them, only compeleted freight runs on NTP and there the wheelslip was not any challagne to overcome at all as well.
     
  5. breblimator

    breblimator Guest

    This feels scripted for all German trains too. For example, if it is wet, and tractive effort per axe is 30kN+, we got wheel slip everytime in the same moment, etc. Schematic like train :)
     
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  6. deeuu#6908

    deeuu#6908 Active Member

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    The physics involved with wheelslip are pretty predictable, it's not like a car where the input of power is granular (at least not on trains with power notches), the the coefficient of friction is pretty much either wet or not, not like a road where the CoF changes wildly, and the weight of the train doesn't change that much (passengers are a small percentage of the overall weight), you could quite easily write a short equation to find the point where the wheels would slip vs not, power over this, slip, power under this, no slip.
    I'm not a train driver so I don't know how realistic it is, but from someone who has a physics degree, it doesn't appear to be glaring (waits for a train driver to come along and blow my ramblings out of the water!)
     
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  7. tsw2

    tsw2 Well-Known Member

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    Yeahy the simulation seems rather terrible often. With the 101 for example you will basically always get wheel slip if you go above 75% throttle and summer or rainy autumn make zero difference.... something is wrong here.

    Basically it's seems scripted and all the talk about "Simugraph" seems just for show...
     
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  8. ARuscoe

    ARuscoe Well-Known Member

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    I'm fairly sure this has limited implementation within TSW so I would imagine the "to slip or not to slip" is almost like a switch
    Certainly when I'm driving in low adhesion it's almost metronomic "notch 2 to 15mph, notch 3 to 30..." no matter what I'm driving
     
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  9. rennekton#1349

    rennekton#1349 Well-Known Member

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    Well the 101 does have super slip which is a normal part of the train as said by tsg. So you aren't supposed to apply full power from the start. It's not 'wheelslip' but the game shows it as being wheelslip
     
  10. argh.bailey

    argh.bailey Member

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    I can't say I have experienced anything other than it purely being based on throttle notch & current speed. That is of course except the 313 which seems to have a massive jerk & wheel slip every time you increase power.

    I do have a vague memory from when I first started with TSW that the 166 felt quite good, with the hissing & ticking of the WSP when trying to brake a bit too hard. That might be more down to it having a noticeable effect rather than a better simulation.

    Some form of unpredictability would be great and would really keep you on your toes in bad weather. Recently playing SEHS felt a bit tame roaring into stations in brake notch 3 in the snow just because you could.
     
  11. tsw2

    tsw2 Well-Known Member

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    The 101 drives very different in Zusi and of course I don't apply 100% throttle to get moving...
     
  12. guardupfront

    guardupfront Active Member

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    Wheelslip isn’t a simple science in reality and tbh there are so many variables that DTG won’t have a hope of *accurately* representing just how random sometimes it can be.
    That being said, the fact they’ve even tried to is a start and it can be tweaked as new ways to measure factors develop.

    In reality I’ve had the worst days with a terrible unit and not slipped once, and I’ve had a good unit that has almost come to a stand because it’s slipped and slid until it started to lose speed. There are many factors both on train and on route to consider, it’s a big ask for realism, and may not even be enjoyable if you get your gaming validation from being anywhere near on time at your destination…
     
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  13. guardupfront

    guardupfront Active Member

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    As a physics grad, you’ll probably understand the mechanisms way better than we do tbh! We only see the what, not the why (only our perception of why)!
     
  14. DominusEdwardius

    DominusEdwardius Well-Known Member

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    TSW implementation isn't "wrong" persay, but the adhesion could probably do with a bit of randomness to it. Currently it is a specific value which does vary with wetness/Snow. Say it is 0.1 in the wet, it is entirely correct that a unit would slip say in notch 3 and not in notch 2 because each throttle notch on modern stuff usually will give a certain tractive effort value. Going from Notch 2 to 3 may cause the tractive effort to exceed the adhesion limit and cause it to slip. TSW is entirely correct here, what it could do with is a bit of noise to vary it randomly between say 0.07 and 0.13 so when it is low Notch 2 may cause it to slip.

    Really its just a product of how modern units are controlled really!
     
  15. tsw2

    tsw2 Well-Known Member

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    I don't notice a difference between raining autumn and clear summer most of the time. It's the same value always
     
  16. matt#4801

    matt#4801 Well-Known Member

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    It's not perfect but in real life on trains with notches you will always know for example out of station A with gradient of X in snowy conditions you will get away with notches 1 and 2 but pushing it up to 3 will always make it slip and this is recreated quite accurately and is different between conditions though I've no experience with most the trains in game so can't say every train is perfect to how it reacts in real life. Its the braking which needs significant work as wheel slide doesn't seem to exist.
     
  17. solicitr

    solicitr Well-Known Member

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    The 101 is a special case, because it's designed (IRL) with limited wheelslip as a feature. Often you'll get the HUD slip indication when the loco is doing what it's supposed to be doing.
     
  18. solicitr

    solicitr Well-Known Member

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    As far as a train is concerned, wet is wet; there's not really a "wetter = more slip" situation.
     
  19. guardupfront

    guardupfront Active Member

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    Okay, this isn't true. There are definitely degrees of wet. Sometimes harsh rain means less slip as contaminats are washed away and light drizzle can be a nightmare.
     
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  20. tsw2

    tsw2 Well-Known Member

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    There is 100% wet and wetter...
    For example, leaves on the track during autumn generate much more slip. Not simulated in TSW at all currently
     
  21. Maik Goltz

    Maik Goltz Well-Known Member

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    Zusi can't simulate super-slip. TSW can do it. The oddity of it is that you have only one type of slip indicator in TSW yet (what is totally ok because super-slip is a rar thing and does not need a special indicator in a game that has one loco with such a system).

    As already explained a lot in the forums, i will do it for you again, in a short. The difference between slip and super-slip is the fact that super-slip is expected, allowed and intended on that loco. In the real loco it switches the ability on when you put the throttle above about 75% from about 85kph (the max-force speed of that loco). In TSW its a bit different as it was not easy to get it running at all in the limited amount of time that was given to develop it. So, it starts there at about 60% throttle and at any speed. You surely can put the lever to 100% in the 101 and it will not slip but super-slip. You can clearly see that, because it does not lose much TE. It still speeds up fast, even if the HUD indicator says it's slipping. Try it. Other locos would lose the whole TE and basically slow down to a stop when you don't stop the slipping by reducing the applied power.

    Also need to say, that super-slip on the 101 is not used anymore todays. For different reasons, but mainly because of material wearing and resonance of the wheels what can cause problems with other parts.
     
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  22. tsw2

    tsw2 Well-Known Member

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    If it is not used in current 101s I would have the super slip rather not implemented at all.
    It's a bit annoying the way it currently works since you basically never can go over 75% throttle until you reach 100 kmh without the train slipping heavily and the indicator going berserk
    But if this is realistic it's of course ok.
     
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  23. Maik Goltz

    Maik Goltz Well-Known Member

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    You didn't understand what i said. The train is not heavily slipping. It just super-slips, so you get max-TE onto the tracks with a bit of slip and that indicator on. The wheels are not much slipping at all. Compare to other locos. When they slip, the produce lesser or even zero TE then. The 101 still accelerates like crazy when slipping (because it's intended to do so and is not wheelslip as expected from other locos).
     
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  24. ARuscoe

    ARuscoe Well-Known Member

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    This isn't my understanding of the situation, and in fact it's less about "wetness" and more a case of "interruption of friction"
    Steel wheels on steel rails means that friction is hard to come by so slipperiness such as oil, contaminants or leaf mulch will certainly cause trains to lose grip on the rail. Heavy rain would wash much of these issues away so although the rail would be wet, and this would reduce friction somewhat it's much WORSE when it's only a little wet, but much more slippery
     
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  25. guardupfront

    guardupfront Active Member

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    This hits the nail on the head from my personal experience
     
  26. cwf.green

    cwf.green Well-Known Member

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    Slip (sometimes called creep) is a measure of the difference between the rotational speed of the wheels and the translational (linear movement along the track) speed. Think of it this way, if the wheels are rotating at 100 km/h but the train is only moving at 70 km/h you have wheel slip.

    Adhesion depends on this slip speed (or slip percentage). For very small amounts of slip the adhesion actually increases, but then it goes down (looks like a bulge with the top around 2.5-5% slip percentage). Here's an example of what I mean.


    Locomotives with super slip/creep control takes advantage of this by intentionally slipping just a few percent. This is what the BR101 does. Like Maik mentioned, TSW simply displays the "wheel slip" indication if the slip is above some percentage, but that means it shows the wheels slipping even for super slip.

    Also TSW wheel slip is not "on or off", it is based on the "wetness" by interpolating between two values (max and min adhesion). If I recall correctly the minimum adhesion is not for maximum wetness (i.e. pouring rain) but rather for some smaller wetness level (corresponding to drizzle or maybe just moisture, can't remember).
     
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  27. breblimator

    breblimator Guest

    But is it possible for the track to be more or less slippy or just in slippy or not state? BR o7
     
  28. DTG Matt

    DTG Matt Executive Producer Staff Member

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    Speaking to drivers, and has been explained above, in reality, and in the sim, "a little light rain" is a lot more slippy than "a whole ton of storm" - because a light rain adds to the film of crud on the track, but a whole ton of storm washes and cleans the track somewhat, actually reducing the problem (though its still worse than it being dry of course).

    The graph is max adhesion at dry, rapidly escalating to poor adhesion for a low wetness, dropping back to not-bad adhesion with more wetness. Snow is more simple, it's just bad. :)

    Track in the game, and in reality, is never "slippy on / off".

    BUT as also explained above, it's an immensely complex subject.

    Matt.
     
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  29. bescot

    bescot Well-Known Member

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    I do like the 323 during wheelslides. Although I didn't hear the WSP clicking during braking in heavy rain it was clearly doing something as the regen kicks in and out and is replaced by full air brake. Nice.
     

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