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Tsw 2 Adhesion.

Discussion in 'PC Discussion' started by jeanmarc094, Sep 9, 2020.

  1. jeanmarc094

    jeanmarc094 Active Member

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    Why is there adhesion in the underground part of bakerloo??? turn that off.
     
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  2. Inkar

    Inkar Well-Known Member

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    Guess you mean that you get "rain" and "snow" adhesion when the train is in the underground section of the Bakerloo line. Yep, I think we should get "dry" adhesion when the train is underground, no matter what the weather conditions are outside.
     
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  3. jeanmarc094

    jeanmarc094 Active Member

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    yes
     
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  4. londonmidland

    londonmidland Well-Known Member

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    Perhaps this is a limitation of TSW 2? So the game cannot differentiate between tunnels and open surfaces?

    Although saying that, it knows not to rain or snow inside tunnels so I’m not too sure why adhesion effects are happening in the underground sections?
     
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  5. LimitedEdiition

    LimitedEdiition Well-Known Member

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    This is one of those tricky things where there's more nuance than just "no adhesion in tunnels." In New York City, when it rains, some subway/underground railroad tracks have visible run off from storm drains that may cause wet conditions underground. Also a LIRR employee that shares a Discord server I'm in, mentioned that there was an instance (although they are rare), where an M7 had such severe wheelslip, that it overshot by 7 cars, because it was snowing at East New York (pretty much an underground station). When there are wet conditions, they can still affect underground tunnels.
     
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  6. breblimator

    breblimator Well-Known Member

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    I am afraid DTG did't know that :) But, superb history!
     
  7. mokady

    mokady Member

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    First of all this new "Adhesion" thing in TSW 2 is ofc broken.
    CSX HH for example:
    - You have 3 options: dry rail, wet and snow
    - As far as I know they just made 3 limits and after you reach them, You get wheel slip (AC44CW has around 370kN at snow and 500kN on dry rail).
    - Dynamic braking is completely broken. You get wheel slip while using it (it is impossible in real life). It is also "inverted". On AC44CW the faster you go, the less force they produce which is ofc incorrect. We ended up with "simulation" that gives you 100kN at 70 mph, 400kN at 2mph and when you got to 0 mph it drops from 400kN to 0 kN in one second making wheel slip in process and spining (yes spining!) wheels at 200 mph for about half a second. This show that DTG doesnt care about their products and they have 0 Quality Check.
    - Not to mention sanding doesnt do anything. You get wheel slip at 400 kN and cant get up grade? Good luck beasue sanding isnt working exept that you can press button. :)
     
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  8. breblimator

    breblimator Well-Known Member

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    Why are you destroying my dreams? :D
     
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  9. mokady

    mokady Member

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    I am so fed up with this "game" that I will write a long post about overall "state" of this game. I preordered first CSX HH release (I dont even know how long ago it was) and all I see that it is worse than before. But I need to make some research so "they" cant say I'm wrong in any way.
    There is one truth about everything: WE ARE TESTERS. They dont have any beta release becasue EVERYTHING is in BETA but we pay for it. :(
     
  10. breblimator

    breblimator Well-Known Member

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    Mostly you're right, but I think it's still a very good train game ;)
    EDIT: I try to forget about ALL THESE LITTLE PROBLEMS...
     
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  11. rat7_mobile

    rat7_mobile Active Member

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    PS. For all kind of software, it is now the norm to use the end users as beta testers, and I am not pointing to any developer or company in particular
     
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  12. TheShotte

    TheShotte Active Member

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    I'm too tired right now to argue this post completely, but either you had wheelslip cause you were applying other brakes or maybe you had the MU switch set to Trail or something, or otherwise were doing something without full knowledge. I've used them and never, ever had wheelslip hauling 5 to 7k tons. Also, sanding does indeed work, but it's not a miracle fix. If you're screwing up, you're screwing up.
     
    Last edited: Sep 10, 2020
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  13. byeo

    byeo Well-Known Member

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    It's a known issue, I raised a ticket with DTG about it and had this response yesterday:

    Hello,

    Thank you for contacting us regarding an issue with TSW2.

    Unfortunately, there is a known issue regarding wheel slip in the Underground of the Bakerloo Line, when it is raining. We value your feedback and please accept our apologies for any inconvenience caused. This issue has been documented and flagged for further investigation by the development team. At this time we do not have any further updates.

    Please monitor our official community channels for updates to this product.

    This concludes our support on this matter and ticket will now be closed. Please feel free to contact us again if you need any help with any other matter.

    Kind regards,

    Chris
    Customer Support Advisor
    Dovetail Games Customer Support
     
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  14. graeme.norton1

    graeme.norton1 New Member

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    As you say you don't get wheelslip when in dynamic braking but you certainly get wheel slide in dyno, to much dyno poor rail conditions wheel locks and you slide.
     
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  15. jeanmarc094

    jeanmarc094 Active Member

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    cool
     
  16. mokady

    mokady Member

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    Yep and game shows me "200 mph" for 1 sec and you can also see this when in external camera. Even if it was possible to get wheels "locked" than it should be giving 0 mph (wheels not spining).

    You are one of "them". Sanding doesnt work in CSX HH. You can get wheel slip without any problem on dry rail with everything setup correctly. I was playing CSX HH from it's original release and it is getting worse.
    Also:
    -lights dont flash when you use horn in AC44CW
    -distance counter doesnt work in AC44CW
    -horn sequence button doesnt work in AC44CW
    - "applied handbrake" icon on back panel is non-stop highlighted even if everything is released - also in AC44CW

    I dont drive SD40 that much so I dont know what is broken in this loco but I bet it is same scale as for AC44CW

    So go on and defend this poor example of a train sim.

    Once again, this is REMASTERED CSX HH :)
     
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  17. maxipolo12

    maxipolo12 Active Member

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    Please add the flags for old DLCs in the menu !
     
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  18. conrail

    conrail New Member

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    I have a lot of fun.

    The defense rests.
     
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  19. LimitedEdiition

    LimitedEdiition Well-Known Member

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    Anyone know if the trains from the second wave of preserved content all have adhesion physics?
     
  20. fanta1682002

    fanta1682002 Active Member

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    class 31 m3
     
  21. Inkar

    Inkar Well-Known Member

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    I think there is no difference between the first wave and the second wave.
     
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  22. jeanmarc094

    jeanmarc094 Active Member

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    YES THIS!!!!!!!!!!!!!
     
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  23. TheShotte

    TheShotte Active Member

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    One of who? People that doesn't believe in something unless provided evidence to the contrary, who does not consider a post by some salty dude as such? I know 100% that sanding works, and you're talking trash, either because you don't know any better or because you're straight up lying. If I'm led to believe that you are lying about 1 part of your post, the rest of your post regardless of what it is is automatically discredited. Again, sanding is not a miracle fix, just like in the real world, too much torque is too much torque, also, AFAIK you might be using the wrong Sanding button and sanding the train instead of the loco wondering why it's doing nothing to your traction. In any case, please provide some evidence (feel free to record video), otherwise, to me, whatever you say holds little weight.
     
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  24. davidh0501

    davidh0501 Well-Known Member

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    Ofc there is moisture in the underground.
    Bakerloo even had flood doors installed at the start of the war in case german bombs breached the banks of the Thames.
     
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  25. cwf.green

    cwf.green Member

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    So which one is it? First you said it is "impossible" to get wheel slip using dynamic brakes and now you are agreeing with the other guy that it's possible.

    You have a very confused understanding of physics. Other than that wheel slip won't occur at the exact same tractive effort level every time, basically everything you said above is incorrect.

    1. Of course dynamic brakes can cause wheel slipping, why wouldn't they? As long as the force is larger than the normal force multiplied by the coefficient of friction you have wheel slipping. Tell me why this can't occur for braking?

    2.
    And why is this incorrect? Do you expect the brake force to be 400 kN at 70 mph? Do you expect it to be 400kN at 0?
     
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  26. DTG Natster

    DTG Natster Community Manager Staff Member

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    Please try to not to get into an argument with other users while expressing your opinions, absolutely nothing wrong with a debate but please keep it polite with each other.
     
  27. cwf.green

    cwf.green Member

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    Not sure if this was aimed at me. I tried to reply in a blunt/straight forward way but not rudely, since I felt a lot of false statements were made in a self-sure manner. Perhaps I miscalculated and it crossed over into rude territory.

    Back to the topic at hand: I have noticed something very neat with the way the adhesion is simulated in TSW2 (not saying it is without fault) and that is that the coefficient of friction seems to depend on the speed, which is actually realistic. This means that if you need 280 kN to slip from start you may slip at 250 kN at 60km/h and 220 at 80km/h and so on. So you can be safe from slipping at a certain throttle setting but then get caught at higher speeds if you were just on the edge.

    I have a suspicion that this dependence is still linear like the one for braking, which I think is wrong although I have less detailed information about the adhesion dependence of speed compared to the shoe-wheel friction dependence of speed, but it is still nice to see something in the right ballpark being implemented.
     
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  28. Dinosbacsi

    Dinosbacsi Well-Known Member

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    Dynamic brakes can't cause wheelslip, as dynamic brakes simply are not able to get a wheel stopped. This is the reason trains that usually use dynamic brake for slowing down (like the M7 or the M3) still need air brakes to stop completely, as at low speeds the dynamic brake does nothing.

    Go drive the M7 on LIRR and see how it will use electric brakes for slowing down, then it will apply the air brakes automatically under 6mph to stop. Because electric/dynamic brakes by themselves cannot get a wheel stopped. So obviously they can't cause wheelslip either, which is pretty much the reason they use them on freight locomotives on downhills in the first place.
     
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  29. LeadCatcher

    LeadCatcher Well-Known Member

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  30. stujoy

    stujoy Well-Known Member

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    I’m assuming you’re referring to wheel-slide not wheel-slip. A wheel doesn’t have to be completely stopped to be sliding along the track, it just needs to be rotating more slowly than it would be with full grip on the rails. If the braking force is enough for grip to be lost due to poor adhesion then the wheels will slide along the track until the braking force reduces and grip is regained. It is also possible for the wheels to completely stop once the grip is lost causing true wheel-slide.
     
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  31. cwf.green

    cwf.green Member

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    You raised some interesting points, but ultimately I'm not sure I'm convinced. As long as you make the velocity of the wheel in the fixed train frame lower than the velocity of the whole train you would cause a slide, don't you think? This does not require the wheels to completely lock up.

    EDIT: I see that Stujoy basically said the same before me xD
     
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  32. Dinosbacsi

    Dinosbacsi Well-Known Member

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    They are talking about completely stopped wheels in this case though, not wheels slowly rotating. And dynamic brakes, as far as I know, will never be able to completely stop a rotating wheel.

    The only "exception" I can think of is trains with automatic brakes like the LIRR M7 or similar modern EMUs, if the dynamic brakes slow the wheel down into a slipping and slowly rotating state (as you mentioned), then because the train think it's going slow it applies the air brakes, therefore really locking up the wheels. Though I think most modern trains should have protection against this, I don't know.
     
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  33. Callum B.

    Callum B. Well-Known Member

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    DC motors can't, but AC motors can. GEVOs actually have "roll-back protection" whereby the electric motors will prevent the train from rolling backwards on a hill using rheostatic braking force until the prime mover produces enough amps to propel the train uphill. Refer to LeadCatcher's PDF link (around page 18) for more a little more info. DC motors taper off below 15 MPH whereas AC motors are actually capable of bringing a train to a stop--albeit slower than air braking below 3 MPH. AC motors taper off linearly at about 0.3 MPH.
     
    Last edited: Sep 14, 2020
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  34. cwf.green

    cwf.green Member

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    I had a discussion with someone about this a while ago. If the generators (what the motors essentially are during dynamic braking) are actually providing force at 0 velocity, wouldn't that imply that they are in fact acting as motors and powering (but in reverse)? If you think about it, when speed is zero there is no kinetic energy to convert to heat (resistors) by way of electrical energy.
     
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  35. TheShotte

    TheShotte Active Member

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    Yeah this sounds right. That's why you don't use Dynamic Brakes to stop your train, but rather to slow it down.
     
  36. mokady

    mokady Member

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    I will read this in free time but if You have some time just test how dynamic braking works now in CSX HH (TSW2). They generate more force the slower You go which is total BS (tested on AC44CW). Also maybe dynamic braking can couse micro wheel lockup but I am almost sure it cant block it for more than few miliseconds because if wheels dont spin than AC motor would not produce any resistance. It is similar situation if You are sitting on a chair and in the same time trying to lift it up.

    As far as I remember BR 185 has properly modelled dynamic braking and of course the slower you go the lower force is generated by motors.
     
  37. cwf.green

    cwf.green Member

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    We've already had this discussion. AC4400 are AC locomotives as the name implies, they will produce max brake force down to a very low speed. So it is *not* "total BS". Your comment about the lockup is system level specific not a statement about the fundamental physics.

    If the brake force of the dynamic brakes is higher than M*g*µ then the wheel velocity will be lower than the locomotive velocity which is by definition a slip ({F_traction or F_brake} > F_normal). The wheels will keep decelerating due to the dynamic brakes now lowering the angular momentum of the wheel/traction motor moving parts rather than the train momentum until the wheel velocity is low enough for dynamic brakes to fade out.
     
    Last edited: Sep 18, 2020
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  38. Anthony Pecoraro

    Anthony Pecoraro Well-Known Member

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    A fix for this dynamic brake issue is on the roadmap.
     
  39. 7orenz

    7orenz Well-Known Member

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    So, am I the only idiot who like and have a fun with the new adhesion physics? :D

    Off course, I suppose we are still far from the real life "details" but the new adhesion system, generally, looks very good :)
     
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  40. kylel2036

    kylel2036 Well-Known Member

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    Nope you aren't the only idiot :). The physics are interesting to say the least
     
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  41. davidh0501

    davidh0501 Well-Known Member

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    Since I’ll never ride in the cab of an AC4400 I won’t seek perfection in the modelling.
    As long as it’s a reasonable approximation I’m happy.
    Suspect it varies amongst machines due to age, servicing, wear & tear etc. anyway.
     
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  42. mokady

    mokady Member

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    I read this paper and now I start to undestand that in AC you control frequency with VFD so if your speed is going down locomotive will adjust frequency for the motors. But still how you can manage to have this much braking force at near 0 mph is beyond me.

    Ok so next question about sanding. Does it work or not? I tried to use it and it had no effect on max traction force I could produce.
     
  43. LeadCatcher

    LeadCatcher Well-Known Member

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    In the scenarios where I have utilized sanding, it appears to work. You still have to use power judiciously and can’t expect that you can add massive amount of power immediately as you can on locomotives that have anti slip systems, but it does allow a little more aggressive throttle than without sand.
     
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  44. cwf.green

    cwf.green Member

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    Good question about the brake force at zero. You cannot regenerate kinetic energy as electrical energy if there is no kinetic energy so no generator will work at 0 velocity. However, what you can do is to simply drive the motors in reverse. So the "brakeforce" at zero is simply just reversed motor force or motors giving torque in the opposite direction.

    EDIT: Quote taken from wikipedia section on VFD:
    "Torque generated by the drive causes the induction motor to run at synchronous speed less the slip. If the load drives the motor faster than synchronous speed, the motor acts as a generator, converting mechanical power back to electrical power. This power is returned to the drive's DC link element (capacitor or reactor)."
    My understanding from this explanation is that if load drives the motor slower than the synchronous speed the motor will act as a pure motor, but during the deceleration you can vary the frequency to gain regenerative braking even for relatively low speeds.

    I'm not sure about the sanding, I'd have to check it. Best way is to brake the train and then just pull on it with the locomotive until it slips and then engage sanding and see if you get traction again. If the train is un-braked you might have force fade from the power curve and that might trick you that sanding is working.
     
    Last edited: Sep 19, 2020
  45. mokady

    mokady Member

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    I think that I read every possible train braking manual that is on internet for train engineers in US and every single one states that AC motors can have full DB as far as to near 0 mph. Also sanding (in real ES44DC/AC) works only until you reach 15 mph or when computer detects wheel slip (either DB or normal operation) and have 3 or 4 steps of dealing with it. Reading this paper you posted helped a lot.

    I was wrong and You guys were right !


    I think this is how Electric Parking Works, it is applying some current to motors (it can of course work like You described but dont we all have caution signs near throttle that before changing to DB the throttle must be 10 sec on idle? It could be too rapid change for electronic equpiment).
    If we are talking about stopping moving train than VFD will just lower frequency of stator to some max value (page 80 graph shows that when going 60 mph it was around 40 Hz and when modelled train stopped it was almost 0 Hz). This is explained from 16 page. Graph on 18 suggest that rotor must spin 15% faster than stator field is rotating (VFD controls it) to have max DB force. It is quite genius and it shows how VFD changed how AC motors are used today. I watched whole video about how VFDs are working.
     
    Last edited: Sep 19, 2020
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  46. cwf.green

    cwf.green Member

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    Hey, no problem. Most of this stuff is super esoteric so it is quite expected to miss details etc.

    By the way, I found a video that I thought was super cool on youtube. Some lunatic made a homebuilt VFD from a function generator (I think) and an AC motor etc. It basically sounds like your garden variety subway train:
    I love it.
     
    Last edited: Sep 27, 2020
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