Heavy Us Freight Downhill Braking

Discussion in 'TSW General Discussion' started by pterocles#7018, Mar 11, 2022.

  1. pterocles#7018

    pterocles#7018 Active Member

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    Hi, advise please the correct method of heavy freight downhill braking techinque.
    I usually start with dynamic, but after a while if the train is really heavy (loaded coal wagons) the train will accelerate. Then I usually start to add a bit of auto brake (initial reduction - 20%), then the train slows down quickly. So I play with the two brake types all the time what I belive is not really realistic.
     
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  2. breblimator

    breblimator Guest

     
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  3. breblimator

    breblimator Guest

    And do not forget to bail off when using dynamic brakes. BC has to be zero.
     
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  4. Lamplight

    Lamplight Well-Known Member

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    Long story short - if dynamics up to around B4 are enough then you can just stick with them (some railroads may have rules against this though). Otherwise, apply a minimum application with the auto brake and use the dynamics to fine-tune (while making sure to bail off the loco brakes). If you still need more than half of your dynamics, apply more air brakes and repeat.
     
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  5. pterocles#7018

    pterocles#7018 Active Member

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    Thank you Lamplight, always like to learn.
    Tomorrow i run another service to try the right way.
     
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  6. solicitr

    solicitr Well-Known Member

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    Also- very important: start with minimum reduction and then add brake pressure gradually as needed, because you don't want to reduce or release the train brake once set, until you're at the bottom of the grade. (in that connection, give the train brake time to actuate all the way back; don't just assume "that's not enough" a second after moving the handle. It takes time for a pressure reduction to propagate down a 1/2 mile or more of brake pipe)

    Also: especially on downgrades, a speed limit is not a target. In many cases (especially Sherman Hill), you do NOT want to be running down 1.5% at line speed, because your brakes can't hold the train at that speed. Back when Saluda Mountain was still active, NS took the downhill at all of 8 mph.
     
    Last edited: Mar 12, 2022
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  7. rebrecs

    rebrecs New Member

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    Realistic? Here is my theory. "If," these unreal trains are like actual trains, then what we have to do to bring them down the hill is realistic. If our unreal trains are not like actual trains, then everything is unrealistic to begin with so why bother worrying about it.
    I have never driven an actual train but I have brought a lot of unreal trains down steep grades. I find that twiddling the brakes, sometimes a lot, is unavoidable. This is because you will not find a combination of settings that will last for long. Whatever you do, your speed will in time begin to slow the train too much, or begin speeding up. Going down hill is certainly not time to kick back and read your cell phone messages.
    If things seem to be changing so fast you cant ever take your hands off (i.e. out of control) you are no doubt going too fast. Slow down and it will get easier. Wait until you can do everything on Sand Patch before you even try Sherman Hill. Those trains on SH are 11,000 tons and 1-1/2 miles long. One of them is 15,000 tons. Its a different ball game.
     
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  8. pterocles#7018

    pterocles#7018 Active Member

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    Fantastic, thank you.
    How about hill start? I struggled with it yesterday with a very heavy coal train on SPG. I finally managed to start but snading light was on for minutes.
     
  9. Dinosbacsi

    Dinosbacsi Well-Known Member

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    For hill starts apply the loco brake and release the train brake, so the cars behind you are free and it's only the locos holding the train. Then add throttle and slowly release the loco brakes as well.
     
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  10. pterocles#7018

    pterocles#7018 Active Member

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    And will the loco brake hold 10000t train without rolling back?
     
  11. Dinosbacsi

    Dinosbacsi Well-Known Member

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    It should. After all, the locomotives have enough grip to get the same train started or brake them just by the dynamic brakes (which obviously are loco-only brakes as well). So keeping the train in place should not be a problem either, yeah.
     
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  12. breblimator

    breblimator Guest

     
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  13. solicitr

    solicitr Well-Known Member

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    Holding a stopped train in place doesn’t require nearly as much force as stopping a moving one
     
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  14. DTG Matt

    DTG Matt Executive Producer Staff Member

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    My approach on transition from up-grade to down-grade is (while constantly monitoring speed):

    Reduce power as the train crests gradually, as you need less power as there's less of the train going up.
    Start dynamic braking once you're off power, again always aiming to maintain a sensible speed, start applying and increase as needed.
    Once you get beyond about B4, kick in a minimum set on the auto/train brake and ensure that the locomotive is bailed off
    Over the next few minutes as the air brakes take effect on the rest of the train you'll feel increased braking effect (somewhat mitigated by more of the train cresting the hill) - counter any excessive braking by reducing dynamic brake a bit.
    At some point, the whole train will be on the down-grade and depending on the amount of gradient you'll need to be applying more dynamics to maintain speed again.
    If you find you're needing excessive dynamics, drop in a little more auto brake (little!) and the counter the braking effect over the next few minutes by reducing dynamics a little again to keep it all balanced.

    It's a slow moving careful balancing game, if you stay on top of it you should never need to be making any quick, sudden or large changes, all small movements. Particularly for the train air brake, you want to be making small applications and feeling how its going remembering each change could take some minutes to fully reflect in the braking of the train as all the cars adjust their brakes. The worst thing you can do is apply too much air brake because US brakes cannot partially release - you may be able to counter it by reducing the dynamics a lot in exchange for losing a bit of your control over the train but if it comes to it, you are much safer letting the train come to a halt, holding on the loco brake while the brakes recharge and then setting off and trying again - don't release the air brakes on the run and hope you'll be able to use them properly before you're going too fast again.

    Remember that on the auto brake its not the position of the auto brake that determines the amount of braking, it's a complex combination of the brake pipe and service reservoirs on each car. If everything is fully pumped up then it works as you would expect - but if you release the brakes and then try to re-apply before they're all pumped back up you will get less brakes than you expect and need to push the auto brake lever further forwards to get similar levels of braking. Eventually, if you do this wrong enough times (and it doesnt take much) you will have lost your air (there is a railroaders expression for it I won't repeat here!) and your only safe option is to dump the emergency brakes and stop and then wait 15 minutes for it all to recharge or risk a runaway. Never let it get that far :)

    If you use the auto brake lever to set the ER down from say 90psi (the fully released) to say 80psi, then this will cause the BP (Brake Pipe) to gradually drop down to the 80psi, and as it drops 1psi the brake cylinders will be filled with 1psi out of the service reservoir on each freight car, which results in a 2.5psi application on brake cylinder (since that's smaller, so the same amount of air gives greater pressure). So your drop from 90 to 80 psi ended up in 25psi on the brake cylinder. Let's say that's too much and you now release the brakes. The ER rapidly jumps back to 90psi (it's job is to move quickly), the brake pipe begins pumping back out of the Main reservoir and going up slowly - it will be higher pressure at the front of the train vs the back - the increase in the brake pipe causes the brake cylinder on each freight car to vent completely - brakes are now off entirely - and the service reservoir begins charging up from the brake pipe.

    So, let's say the brake pipe at the front of the train is back at 90psi, and at the rear of the train its only at 82psi and you decide to make a new application of the brakes and you go for another 80psi - same as before.

    This time, the front of the train will see a 10psi drop and you'll get 25psi in the brake cylinders, but as you proceed towards the back of the train, you get less and less of a drop - to where the rear car is only seeing a 2psi drop, and that results in only 5psi in the back of the train.

    Instead of 100 cars at 25psi brake cylinder, you hopefully can see you now have considerably less! At this point you're running down the hill, speeding up in a way you weren't before, exclaiming about bad brakes and you push the brake to 70psi, another 10psi. This gets you 50psi (nearly full application) on the front and 30 on the rear - darn it, now we're over braking, release the brakes again. Except the rear of the train was down to 70psi now and the whole train will take even *longer* to recharge fully to 90psi than it did the first time - you're still going down the hill, you're accelerating, and you're in a death spiral of brake mismanagement that will surely mean you need more and more.

    Small changes, carefully reviewed, always leave yourself head room to correct with the dynamics, run to the speed of the train not the speed of the track, and if it goes wrong - STOP, pump up and try again.

    The SD70ACe on Sherman Hill begins to lose dynamic brake efficacy around 31mph so ideally you want to be under that. Once you get the hang of it you can probably run to 30mph but until then i'd strongly advise limiting yourself to 25 so you have headroom to pile on more dynamics to help buy you time on the air brakes. To give you an idea of how careful this balance is, on a stream when Sherman came out I was carefuly managing around 30mph down the grade but got distracted chatting with viewers - the grade changed very slightly and my speed crept up to 34mph, at this point I no longer had enough dynamics to maintain speed even on full dynamics and we were accelerating. I needed to slightly increase my auto brake to compensate and then use a little less dynamics once it'd recovered, but rather than worrying about overspeeding, I did it slowly, and brought the train back very gradually into its preferred speed of around 30mph which also meant I didn't sacrifice much dynamic brake handling.

    For those who don't "get" US Railroading, for me at least, perfecting the transition from up to down and then perfecting the downhill run is massively fun and an enormous challenge to get right and even once you're good at it you'll appreciate you have to watch it like a hawk to keep things running smoothly and safely.

    For hill starts, I will normally start ramping up the locomotive engines to prove power is going to be applied (nothing worse than starting the brake release and then you move the throttle and nowt happens...) but only to notch 1. I'll apply full independant brakes to hold the train and then start the full release on the automatic brake. You don't know what the line up ahead will bring, you might need to stop at a light or for another purpose so you shouldn't leave just because the train is now free running, you should wait for the rear brake pipe to have fully pumped back up to match the front at 90psi. Why? See above - if you get moving when the rear brakes are released which is probably going to be around 70-75 or something, you're basically running with next to no automatic brake available on the rear half of the train and you're setting off already in a bad brake situation. Wait. Every time thereafter that you apply the auto brake and it works smoothly and well you will thank yourself ;)

    Hope this is useful and apologies for the long post.

    Matt.
     
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  15. breblimator

    breblimator Guest

  16. Lamplight

    Lamplight Well-Known Member

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    Can we just appreciate the fact that Matt typed out what we were all probably a bit too lazy to type out on a Saturday resulting in a pretty comprehensive guide to US air brakes?
     
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  17. Calidore266

    Calidore266 Well-Known Member

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    If you want to see Matt demonstrating what he posted above, watch his Sherman Hill streams on YouTube, in which he narrates the process while doing it live. That greatly improved my Sand Patch driving.
     
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  18. OldVern

    OldVern Well-Known Member

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    I'm not sure if TSW does this, but in Run 8 if you apply the train brake while dynamics are engaged, the loco brake does not actually apply. Apparently this is correct and threw me at first, until I queried it on The Depot forum and confirmed actually the case.
     
  19. breblimator

    breblimator Guest

    Depends on the loco :)
     
  20. pterocles#7018

    pterocles#7018 Active Member

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    Thanks Matt for this detailed explanation, now I have a lot to think about.
    I have been practicing now for two days, not an easy job.
     
  21. pterocles#7018

    pterocles#7018 Active Member

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    I hope JustWentSouth dont't mind if I copy here what I have just found in another thread from last year.
    It can help understanding this topic (it helped me anyway).

    As you can see this is from Trains Magazin.

    9D1518B5-067C-4DDF-9F76-5BABBA11B2FE.jpeg
     
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  22. pterocles#7018

    pterocles#7018 Active Member

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    When I went over the crest yesterday after reading Matt's detailed comment, my train started to accelerate. I put dynamic notch 1...2.....3........4......finally 5, but in kept accelerating. No problem I thought, lets put automatic to minimal reduction and decrease dynamic. So I did.....auto to minimum.....dynamic down to 4...3....2....1......off........train just getting slower and slower........oooops I stopped. No worries let's do again......same process.....same result.
    It is important to note that the train was only partially downhill when I did this test. But: it was accelerating quickly 3/4 was still downhill and despite dynamic notch 5. As you guys wrote that I should not go over notch 4, I applied auto brake......train stopped.
    As soon as the whole train was over the crest all went fine.
    So now what? What did I do wrong while I was along the crest?
     
  23. breblimator

    breblimator Guest

    Practice makes the master :)
     
  24. solicitr

    solicitr Well-Known Member

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    Yup. Notice though the corollary to Diagram 4: the air that was in the brake cylinder was vented off to the atmosphere and is lost. It has to be replaced- but refilling the reservoir via the (small) refill groove is very slow. So, if you release brakes and shortly afterwards re-apply, instead of a 10-lb reduction you only have an 8.9-lb reduction, = 22 and a quarter pounds of brake force. And worse with each cycle. And that's just with a very modest 10-pound reduction; a full-service very much makes things worse, and it can take a very long time indeed before your brakes are fully charged again (your locos' air compressors are working at it, but it isn't fast). This is why, once your train brake is set, you don't want to release it again if you can help it.
     
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  25. breblimator

    breblimator Guest

    It is true. However, it is difficult to lose the brakes in TSW in this way. I didn't make it - maybe I didn't try hard enough :)
     
  26. DTG Matt

    DTG Matt Executive Producer Staff Member

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    You can certainly go above dynamic notch 4 - it's really about not *keeping* it there. Dynamic notch 8 is quite fierce braking at 30 mph.

    Just like when you're powering up a hill there are in reality limits to how long you want to keep at run8 the same applies to the dynamics.

    When i'm cresting the grade, I don't want to be setting the air until really we're fully on or the dynamics really are struggling, so i'll run up the dynamics as required to maintain speed and if i'm hitting 7 or 8 then it's time to think about that minimum set.

    Matt.
     
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  27. Lamplight

    Lamplight Well-Known Member

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    From what I found online, that doesn't seem to be the limiting factor though. An engineer said online that it's about having room to play with. If I'm already in B6 just to hold the train, then I don't have much of a "safety net" of fast applying (dynamic) brakes in case the gradient changes or I misjudged the situation. If I'm only in B4 though, then I can still quickly crank the dynamics way up if the situation calls for it.
     
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  28. paul.pavlinovich

    paul.pavlinovich Well-Known Member

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    You might find my TSW2 tutorial playlist handy https://youtube.com/playlist?list=PLWi4sYR9zXqWK563hAInWYVxlLeM8-JMb

    Particularly this Dynamic tutorial (It's Sandpatch but the same principles)

    Paul
     
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  29. paul.pavlinovich

    paul.pavlinovich Well-Known Member

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    Yep wiggle room is always needed. No-one wants to ride that rollercoaster. Here is your worst case scenario spelled out https://www.ntsb.gov/investigations/AccidentReports/Reports/RAR9002.pdf
    Essentially
    • Overloaded train with estimated instead of actual weights
    • No air brake test after re-assembling the consist
    • Lack of rest and at least one crew member sick
    • Train handed over on the move without completely stopping
    • No inspection of the train from the incoming crew
    • No hand over from the outgoing crew
    • Non functional dynamic brakes on one or more of the locomotives in the consist
    • Using all the dynamics that were available not realising they were well beyond their limits
    • Not using the service brake until it was way too late which meant it simply couldn't stop and rode the rest of the hill with melting brake blocks
    • Basically the train was a run-away before it left
    All those things are why you need wiggle room. In my second person training, its always emphasised - if in doubt and there's no communication happening in the cab "big hole" (apply emergency brake) and explain it to your driver after you're safely stopped. Better have a driver mad at you than dead.

    Paul
     
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  30. pterocles#7018

    pterocles#7018 Active Member

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    Thank you Paul, I have two questions.
    - It was advised earlier not to use dynamics over 4 - 5 , then you use Notch 8 (I understand there are 10 in your case). So is that allowed to use higher dynamics?
    - Also it was advised not to release automatic brakes until get down the grad what you released. Is that allowed?
    Cheers
     
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  31. breblimator

    breblimator Guest

    Depends on track layout, train weight, weather, experience, signalling, etc.

    Your objective is to maintain speed.

    Ther is no golden rule about notches, PSI, etc.

    There are some prohibitions: e.g. you cannot brake by setting the reverser in the direction opposite to the direction of movement, e.g. you cannot try to stop a train rolling backwards by setting the reverser to the forward plus power position. You have to use the brakes for this.
     
    Last edited by a moderator: Mar 15, 2022
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  32. hyperlord

    hyperlord Well-Known Member

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  33. solicitr

    solicitr Well-Known Member

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    How much dynamic to set is situational: the operative term, mentioned above, is "wiggle room" - do you have some extra braking left in reserve, considering the steepness of the grade, train weight and so on? This varies. If I know that I am on the ruling grade- say, down 1.6% on Sand Patch - and I can hold speed with X pounds of air plus dynamics in Notch 7, then fine, because it isn't going to get any steeper, and when it shallows out a bit I can pull way back on the dynamics without having to release the train brake.
     
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  34. driverwoods#1787

    driverwoods#1787 Well-Known Member

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    The 1989 Cajon Pass derailment with a natural gas pipeline rupture. Locomotives there were SD50 SD60 SD40-2 the difference between that one and the game is that the rear locomotives have drivers which is what the banking comm supposed to represent. Had there been multi-player since 2017-2019 the way it's going to work is the front player lead locomotive telling the rear players who are in the rear locomotives applying the brakes when the front locomotive driver does so.
     
    Last edited: Apr 2, 2022
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  35. solicitr

    solicitr Well-Known Member

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    El Cajon was a goat-rope for the reasons Paul listed: defective loco, inadequate handoff, sick crewman- but the first was the core reason, compounded by the others. That consist didn't have adequate braking for weight and grade, but they didn't know it. Had they known it (adequate handover, brake test), they would have stopped the train and either added traction or removed cars.
     
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  36. paul.pavlinovich

    paul.pavlinovich Well-Known Member

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    As mentioned by Bill solicitr it all comes down to the route. On Sherman I would behave differently and travel MUCH slower. On Sand Patch I'm happy running at (or over when no-one is watching) the speed limit. On Sherman I would not do that because it is so steep. Bill is also very correct that it comes down to route knowledge. If you know for absolute certain that you're holding the train with most of your dynamics and the route does not get any steeper and the weather is dry then go for it. You've still got your air to stop you if needed.

    On the air brakes, I differ from the approach Matt takes (which is fine, every task has many right ways of doing things) and is based on many discussions with engineers/drivers over the years. I use the air brake in the saw tooth method. The concept is you use the dynamics for most of your braking effort and in most places along the line dynamics will be enough to control you. As you start to creep up you would use more dynamics because they act quickly then come back down on the dynamics when you are able to. If the dynamics are not enough to control your speed then do a minimum brake application and let that sit for a few minutes so it has a chance to take effect. If that still doesn't control your speed then give it another squeeze and again let it sit for a few minutes. For these applications most people advise to bail off the locomotives to keep the dynamics effective but I've had conflicting advice here - some engineers say bail off always, others say bail off only if the loco goes into wheel slip. It may come down to the localised training and type of route those engineers/drivers run.

    With traditional Westinghouse (Wabco) air brakes after that initial set you've only got two or maybe three (if you're lucky) more applications you can make without pumping the train back up if you want your wiggle room. For this reason if the first two applications don't slow you down then you want to make your next application a full equalising application (often called full service) where the brake pipe and brake cylinder come to the same pressure and wait for the train to come to a stop. Once it stops apply your locomotive brake on full (and hope its enough to hold you) and release the train brake. It will take many minutes before the rear of the train is fully pumped up and ready to go. Then you can set off again. If the equalising doesn't stop you, on American Westinghouse you've got one last option - they have an emergency reservoir on each car, when you big hole it / go into emergency that last ditch application will apply the brakes on the cars. Note that the system is its own worst enemy as this emergency air is also used to more quickly release the brakes by helping to pump up the brake pipe.

    In the past retainers would have been applied to every carriage/car so that when the air brakes were applied they were physically constrained from completely releasing even with the brake pipe fully pumped back up. I cannot find anywhere that still does this due to modern composite brake shoes - happy to stand corrected - just because I've not found it doesn't mean it doesn't happen.

    On the baby railway where I operate we don't have dynamics, we only have the Westinghouse. We brake with one or two applications until the train is fully under control at about half line speed then fully release. We're only dealing with about 150 metric tons of locomotive and carriages though and the brake pipe is fully pumped in two minutes.

    breblimator you're absolutely correct on modern locomotives - interestinly using the reverser to brake was acceptable practice on steam engines and on some early railways the only brake you had.

    hyperlord you're welcome - I keep doing more, in fact I might do another one for Sherman because the need seems to exist and in places the future Horseshoe route is steeper so the same method can be applied there.

    driverwoods#1787 you are correct, the rear locomotive engineer (probably only one since the coupled locomotives are controlled together) would be applying dynamics when told to by the lead engineer by radio but the lead engineer would control the air brake in the entire train including those rear locomotives. The only exception is banking locomotives (sometimes called pushers) who generally are not connected through with the air. In modern times the computers on each locomotive would be talking to each other by radio to manage the descent and the engineer has much more complex options available like DPU fencing where as they crest a hill for example they might have the rear units pushing in Notch 8 while the front units are in dynamics starting to slow the head end. This is critical with long trains to avoid stretching the couplers so much that they break a knuckle and pull apart. Couplers are designed to fail this way because the alternative is to rip the draw bar out of the car. A knuckle can be (and usually is) replaced by the road crew.

    Paul
     
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  37. solicitr

    solicitr Well-Known Member

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    As I recall the report on the Cajon derailment, the trailing MU engineer panicked and (on his own) decided to pop the emergencies.
     
  38. solicitr

    solicitr Well-Known Member

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    With the caveat that increasing the train brake set without releasing costs you nothing- it's releasing the brakes that vents the system. I find on Sherman Hill, given a not-extravagantly-heavy train, I can hold 30 mph with an initial app plus a couple of pounds, plus dynamics. But I still have a lot of air in reserve to add more squeeze if I need it.
     
  39. hoagy

    hoagy Member

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    The first video linked in this topic used a phrase something like (from memory) "put your fence up". Any idea what that meant?! Sorry if I've misphrased it, but the word "fence" was deffo in there.
     
  40. breblimator

    breblimator Guest

    It is about using DPU in the advanced (different power/brake settings for particular locos) way. Not implemented in TSW.
     
    Last edited by a moderator: Mar 16, 2022
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  41. paul.pavlinovich

    paul.pavlinovich Well-Known Member

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    It might be terminology, but releasing puts air into the system - it releases from the brake cylinders but its going into the train brake pipe and auxiliary reservoirs on each car.

    Normally when you apply it will be in increments governed by the feed valve, most of the time this is 7 pounds.

    The rear helper doing it old style could pull their emergency valve without touching the brake stand and that would apply the emergency brakes from the rear travelling forwards. The lead locomotive would start to fight that application using its compressor, that would get awfully messy much like a break-away.

    hoagy old mate breblimator explained that well. In a massive train you might even have multiple sets of DPU doing different things although how one person keeps track of that in their head amazes me.

    Paul
     
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  42. hoagy

    hoagy Member

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    Thanks for the explanations, much appreciated.
     
  43. JustWentSouth

    JustWentSouth Well-Known Member

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    My bit of advice in this excellent thread: keeping a train stretched out over the crest requires that you don’t hit the crest at track speed and stay on minimum throttle as long as possible, ideally until the rear is over the crest. Then, you can slowly bunch up the train and begin braking with the dynamics.

    On SPG, I find myself using the saw tooth approach with the air because the minimum application is 9-10 pounds on the CSX stock in TSW; this will bring most consists to a halt going down the grade.

    For the SD70Ace, the minimum application is a more realistic 6-7 pounds of air which really allows you to dial in a speed. That’s why I was disappointed to see the SD70 mostly disappear from the SPG timetable. Hopefully, the locos for Horseshoe Curve will have the lower minimum set!
     
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  44. solicitr

    solicitr Well-Known Member

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    Except in the C40, which gets it right.

    Anyway, going down the grade eastbound, if with loaded coal or grain hoppers it takes minimum air (permanently) plus dynamics to hold. OTOH, empty, autorack and intermodal trains can be held with dynamics alone, unless all you have is two SD40s.
     
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  45. driverwoods#1787

    driverwoods#1787 Well-Known Member

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    For two SD-40s Eastbound trips try to make them light which means copying 1878 metric tons RRO petroleum train separation that their horsepower per ton handle without stalling at Start then apply the method described here.
     
  46. rebrecs

    rebrecs New Member

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    Admittedly, I have been driving for over a year using the dynamic break as primary and tapping the air break (auto-brake | train brake) as required. It always worked. However I was running the dynamic at 7 or 8. Though I never got in any real trouble, I was always concerned that I had no headroom if needed. But I kept to what I knew.
    In the early days, I experimented with setting the air brake as primary but abandoned it because I could not imagine that any friction brake could or should be left on for an extended time. I'm no expert in Train brake pads but running down Sand Patch or Sherman where they would need to stay engaged for 10+ miles seems a bit wrong to me. Does one expect to change brake pads at the end of each service? Not to mention the heat.
    I would expect they would get hot and quit working. I have not noticed any consideration for that in the physics model. Its like they are magic in the Sim. Last forever, work forever. I have had some conditioning to believe since neither my truck nor my motorcycle can go down long hills using a friction brake. Its a wreck waiting to happen. Trains are different. (I guess)
    So, when I'm wrong, I say so. I have started using a minimum application of air brakes and then adjusting with the dynamic breaks. Now I am going down hill with dynamic brake settings of like 2 or 3 instead of 7 or 8. It is a whole different experience and I love it. (got me some headroom)
    "I was wrong OK can I go now"
    But I would like to hear more about whether the pads have to be cooled down etc. or whether this "new way" is actually real world viable. I would think they would be less effective the hotter they got requiring the engineer to increase the application - and eventually they would just stop working ( within 10 miles for sure)
     
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  47. Lamplight

    Lamplight Well-Known Member

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    The video linked by breblimator in post #2 was done by an actual engineer, so yes, this is the real world practice. Requiring engineers to have a minimum air brake application on steep gradients is nothing out of the ordinary - there’s a similar rule in Germany above a certain gradient.

    As far as wear and tear goes: Obviously, it’s hard on the brakes. Seeing how the air brakes are not applied very hard (if everything goes right), the wear and tear is probably manageable though.
     
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  48. DTG Matt

    DTG Matt Executive Producer Staff Member

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    You've either got to use the friction brakes OR you have to have *all* your braking done at the front of the trains with all the wagons for a mile pushing up against them - which is probably not safe in reality.

    By using a minimum set of air balanced with dynamics, you have a nice balance of brakng with minimal wear and tear, and brake force distributed down the length of the train for much happier physics :)
     
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  49. solicitr

    solicitr Well-Known Member

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    True. Although IRL a mile-long consist would also have locos at the rear and probably also in the middle.
     
  50. paul.pavlinovich

    paul.pavlinovich Well-Known Member

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    Brake blocks are replaced very frequently. Even our baby 110 ton train sets on the heritage railway I work on has the brake blocks replaced roughly monthly, more often in summer when we run longer and heavier consists due to increased passenger numbers. Modern composite blocks last somewhat longer than old fashioned cast iron. Wheels will dissipate a lot of heat as long as you stay below the point where the grease in the bearings catches fire then all good :)

    If we had proper DPU in game then not all the dynamic braking would be at the front, even now the braking is a simulation of having a second crew in another set of locos at the back isn't too bad.

    It is important to keep the train either stretched or compressed - either should be ok from a physics perspective both in game and in reality. Having them bounce back and forth would set up standing waves which would likely at least brake couplers if not worse.
     
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