P42 speed control and acceleration

Discussion in 'Amtrak Rail Discussion' started by lrh442, Oct 9, 2019.

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  1. Oct 9, 2019 #1

    lrh442

    l

    lrh442

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    How do Amtrak trains running diesel electrics (e.g. P42 Genesis) maintain a more-or-less constant 79mph (or whatever the track speed is)? Is there some form of electronic cruise control? It seems that the engineer constantly moving throttle notches to hold a steady speed would not be nearly precise enough to hold the steady speeds that I see on my GPS or on the track recordings.

    On a related question, when accelerating from a stop on dry rail to track speed does the engineer gradually and sequentially increase run positions or can they skip notches?
     
  2. Oct 9, 2019 #2

    Acela150

    Acela150

    Acela150

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    I believe that the P42's and P40's are equipped with Cruise Control. I know that the ACS-64's, AEM-7's, HHP's, and Acela sets have a cruise function. I have seen them used first hand.

    As to "Notching out" as it's referred to. Each engineer is different. But it's best to take Notch 1 then go to 2 and then open it up. That's only for passenger service though. If you had a freight unit or freight train it's best to notch out one notch at a time.
     
  3. Oct 10, 2019 #3

    Qapla

    Qapla

    Qapla

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    I found these comments with a Google search:
     
  4. Oct 10, 2019 #4

    railiner

    railiner

    railiner

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    Bear in mind, that a moving train is very heavy, and the laws of inertia should more or less mean the train should maintain its speed for a while, before additional power is needed to modulate that speed...much more so than say in your car on a highway...not to mention railroads don't have the steeper grades of a highway...
     

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