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PC Sand Patch Grade, U876-b - Coal - Loading At Shaw Mine

Discussion in 'Technical Reports' started by Bassarnis, Aug 28, 2020.

  1. Bassarnis

    Bassarnis Member

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    When first loading in you are asked to move to a point and start loading coal. You are given the AC4400CW locomotive which has low speed control making it ideal to load the wagons. There are 2 issues that arrise.

    Issue 1: The banking locomotive (which you are not told to enable with the "Banking COMMS" button) is configured incorrectly with regards to it's MU-A valve. Its set to "trail 6 or 26" which applies the breaks. You have to set it to "Lead or Dead" and bail off the breaks either by walking all the way to the back, or use an external camera and mouse over the controlls.

    Issue 2: If you have enabled the "Banking Comms" button and started the slow speed loading using the slow speed control on the AC4400CW , after a certain point during the loading where you start going downhill, the banking locomotive (which doesnt have slow speed control) works against the leading locomotive pushing your speed way higher than what you set in the leading locomotive. At this point you can see the leading loco going into dynamic breaking but its not enough to maintain the set speed. You end up not loading the last 7-8 wagons unless you actively use the breaks.

    The solution i found is to use external camera when you start, switch the MU-A valve to "lead or dead" and bail off the brakes on the banking loco. Afterwards you have to NOT enable the "Banking COMMS" on the leading locomotive, allowing you to slowly load the coal as you are supposed to do. When loading the coal is completed, you can enable the banking loco to help you get up the hill.

    Possible fix would be to replace the banking loco with an AC4400CW instead of what it's currenty, but havent tested if the slow speed control applies to a banking locomotive.

    I've created a ticket mentioning the above. It feels as if the banking locomotive is unessesary. Any thoughts?
     
  2. deans.ma

    deans.ma Member

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    I did this scenario and didn't have any problems. I set up slow speed control for 2mph in the AC44 and let the train do the rest of the work.

    I didn't bother with setting up the locos for DPU operations, because the gp38 is supposed to act as a "shoving platform" for the brakeman to ride on when backing down the branch.

    In real life, the job of the gp38 is done by a caboose, it sits stationary at Salisbury Junction, and when trains need to back down the branch, the couple to the caboose as a safe platform for the brakeman to ride on.

    39°49'39.5"N 79°02'09.8"W

    -Dean
     
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  3. Bassarnis

    Bassarnis Member

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    The problem is if you don't do anything, the banking loco has it's breaks on, so if it worked for you, that means that the leading loco was pushing more throttle than it needed. Its like dragging a wagon with hanbreak on.
     
  4. mancunian#7861

    mancunian#7861 Active Member

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    I am really struggling with this one just to get moving at all! Issue 1 ... I didn't get *any* commands/advice when starting this scenario, just in the driver's seat so didn't get told not to use the banking comms button at all. There *is* no mu-a valve with this loco. I did try walking to the other identical loco immediately behind me but that was as useful as an ashtray on a motorcycle or a chocolate teapot! It's identical to the one I'm driving - or supposed to be driving. Are you sure you're not getting confused with the coal loading tutorial/introduction? Mind you I recall having the same loco for that so no probably not. Issue 2 - you talk about a banking loco - do you mean the *trail* loco behind me? As it's an identical loco, it *does* have slow speed controls but presumably you don't have to set it up behind as well as in front? The brakes in my trail loco are already set to off.

    You give a possible fix as changing the loco with an AC4400CW instead but it already is. I'm wondering/puzzling if maybe this scenario has been changed/fixed/ammended or whatever you want to call it since you played and the one I'm playing? despite the scenario being described as U876-B - that's certainly not the loco(s) I find myself with! :(
     
  5. solicitr

    solicitr Well-Known Member

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    Incorrect. ALL locomotives except the lead should be set to trail. Trail position disables that cab's brake control so that you control them all from the front.

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    NB The issue with gathering speed at Shaw mine has nothing to do with the banking engine: it's a function of the downgrade in the runout and the fact that your train is getting heavier and heavier as it takes on coal. The way to address this is to keep reducing the target speed in the slow speed control, since it necessarily is going to overspeed the target.
     
    Last edited: Apr 26, 2021
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  6. mancunian#7861

    mancunian#7861 Active Member

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    Bill, forgive me please but isn't the slow speed control supposed to prevent your loco going faster than the setting you give it, even allowing for the fact that the wagons are slowly getting heavier, or is it just a quirk of the game? Just curious, that's all.
     
  7. solicitr

    solicitr Well-Known Member

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    It's supposed to try to do so. That's not a guarantee (if you look at the MSD screen, there's a bar graph fpr "speed error" to tell you how far off it is.

    Of course, you can also turn it off and just do it manually.
     
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