Auto Application Of Emergency Brakes/poor Train Handling Point Deduction

Discussion in 'Technical Reports' started by matherwald, Dec 31, 2024.

  1. matherwald

    matherwald New Member

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    I really don't understand what I'm doing wrong here. The "Thermal Expansion" scenario for the Northeast Corridor, ACS 64 Amtrak has two locations where my emergency brakes are engaged. This causes serious point deductions for poor train handling and wheel slip mark downs. The first instance happens immediately after passing an Approach Limited signal aspect, which means slow to 45 mph. As you may or may not know, you are warned at the very beginning of the scenario not to exceed 80 mph for the entire route due to thermal expansion of the rails. So I engage about a 15 percent dynamic brake and 25 percent train break so as to not cause wheel slip. Theoretically I should have ample time to slow to 45 upon reaching that signal aspect. The AWS does sound, but I tap the button to disable it because I'm awake and slowing down. The controls have been manipulated regularly so there really is no reason for the AWS to go off. Anyway, not 5 seconds after I engage the above mention brake levels, the AWS comes on again only now I can't disable it and the brakes engage automatically to 100 percent application. The second time this occurs I don't even know what might be triggering it. I'm at a loss here....really not sure what I'm doing wrong here. I really don't think I'm doing anything wrong at all honestly. Serious responses only please. Thank you!
     
    Last edited: Dec 31, 2024
  2. triznya.andras

    triznya.andras Well-Known Member

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    It's not AWS but the NEC specific system, Advanced Civil Speed Enforcement System - Wikipedia.

    This iteration is rather aggressive. It requires that upon passing a signal or speed board below your current speed, you apply Suspension level braking, which is pretty much Full Service. The silly part is that after moving the handle to release, you'll slow down a further 10mph, so you'll learn to release above the speed limit and smash that Q.

    Some trains ignore it or are more lenient. May favorite is the ALP-45DP where you have to apply a brake setting which still outputs 0 brake effort. The old AEM-7 picks it up but only keeps beeping.

    Signalling implementation isn't perfect, but theoretically there are two types of signals (on the NEC as well): advance and enforcing. Intentionally using the second word. Advance signals are only informative, but enforcing signals apply right there.

    Approach (Limited) and Advance Warning appear to be the same on the NEC with position light signals, top (single) flashing diagonal yellow. In theory the advance warning requires two lights but that's usually reserved for diverging.

    Many years ago I watched a Canadian video explaining that there are permission and speed based signals, and the NEC version is a complete mashup of these. Drivers usually drive as if everything is speed based: advance warning equals approach (limited). Same in the UK which has no official speeds assigned to single and double yellow.

    It's a long journey to get to understand signalling, especially with every single one being quirky. For now, remembering to apply Suspension when there is an in-cab alarm due to your speed exceeding in-cab speed limit, will do.
     
  3. 749006

    749006 Well-Known Member

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    That is a strange way to drive the train.
    Don't try to use the loco brake and the train brake at the same time.
    The train brake will also apply a proportional brake on the loco as they work together not separate.

    US locos don't have AWS (which is the Automatic Signal Warning system used in the UK).
    If the Alerter is causing a problem the Switch it Off until you are used to it.
     
  4. matherwald

    matherwald New Member

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  5. matherwald

    matherwald New Member

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  6. triznya.andras

    triznya.andras Well-Known Member

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    Most modern stock uses blended brakes which in American words means dynamic and train brakes together.
    As far as my understanding goes with two handle locos, you start with electric brakes and once it starts going away, you add train brakes. Apart from winter runs when you'd apply brakes just to make sure no snow is building up (and keep schedule with lesser grip), chances are you'd never use train brakes except to stop and hold.

    One thing to know is, if you apply dynamic brakes manually, it's random whether train brakes will apply blended brakes. Usually not.
    Whether it helps or harms is random. Sometimes dynamics are so strong that limiting them this way avoids wheel slip and worse.
    If my memory serves the ACS-64 has separate brake handles but the power handle has the negative range, too. You're supposed to use it.

    Peter (749006) said something different - avoid loco and train brakes together. The American word is independent brakes.
    Generally loco brakes are only used when you need very little brake application, either because running light, or you're on a petty grade.
     
  7. 749006

    749006 Well-Known Member

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    matherwald If you put your reply inside my quotes it does not properly appear
     

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