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Thread: Friction physics in MSTS explanation?

  1. #1

    Default Friction physics in MSTS explanation?

    Hi there,

    I have been trying to understand how friction is calculated in MSTS, and i have a question about this part in .eng file:
    Code:
    Friction (
    		1070.5N/m/s    -0.10    1.2mph    11.358N/m/s    1.889
    		5.1N/rad/s		1		-1rad/s	0			1
    	)
    I am wondering what all these values represent?
    What i mean with that is, what are these values used for, and what do they represent?
    And am I right they are calculated using the Davies equation?(Or is the davies equation calculated USING these values?)
    And maybe someone does know why they are using davis equation(if i am right, they are) to calculate the values?(and not some other formula)



    Thanks!

  2. #2
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    Some of this is explained in the Turbo Bill doc found here: http://railsimstuff.com/tools.html

    There are additional more detailed discussions at Elvas Tower Forum

    And even more details found here: http://www.coalstonewcastle.com.au/physics/
    http://www.railsimstuff.com
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  3. #3
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    Download fcalc.zip from the library. Contained in the zip is a file called Methodology and Theory of FCalc 2 which includes an explanation of the MSTS resistance physics.
    Beer is not a matter of life or death, it is much more serious than that.

  4. #4

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    Quote Originally Posted by baldwin View Post
    Download fcalc.zip from the library. Contained in the zip is a file called Methodology and Theory of FCalc 2 which includes an explanation of the MSTS resistance physics.
    Quote Originally Posted by pwillard View Post
    Some of this is explained in the Turbo Bill doc found here: http://railsimstuff.com/tools.html

    There are additional more detailed discussions at Elvas Tower Forum

    And even more details found here: http://www.coalstonewcastle.com.au/physics/
    Thanks for the replys!
    Both links were very helpfull and the fcalc documentation also helped a lot!
    But I still have a question.
    Why are there 10 values, and how do you know what to enter there, and how are these values used in MSTS?
    And i also got an additional question about trains(a bit offtopic):
    If a train provides 300kN of power, does it provide that constantly? Or does it fluctate?
    And how does it fluctate?

    Thanks!

  5. #5
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    The MSTS resistance equation has two lines. The first line deals with the main train resistance, the second line is the added resistance for curves. Note that this does not seem to be used in MSTS. For MSTS you use Fcalc putting in the required data and getting back the data to place on the first line. Fcalc can also produce a set of Davis equation figures as well. Those are used in Open Rails where curve resistance is also modelled.

    If a train is producing 300kN of power it is going nowhere.

    Power is expressed in HP or kW and that is a fairly constant force where electric motors are concerned. kN is an expression of the force exerted by the power to move the train and does fluctuate with train weight and speed.
    Beer is not a matter of life or death, it is much more serious than that.

  6. #6

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    Quote Originally Posted by baldwin View Post
    The MSTS resistance equation has two lines. The first line deals with the main train resistance, the second line is the added resistance for curves. Note that this does not seem to be used in MSTS. For MSTS you use Fcalc putting in the required data and getting back the data to place on the first line. Fcalc can also produce a set of Davis equation figures as well. Those are used in Open Rails where curve resistance is also modelled.

    If a train is producing 300kN of power it is going nowhere.

    Power is expressed in HP or kW and that is a fairly constant force where electric motors are concerned. kN is an expression of the force exerted by the power to move the train and does fluctuate with train weight and speed.
    I see, so an eelctric train will provide somewath constant power most of the time, but what about force?
    How is that caluclated in MSTS?(as it doesn't seem to have a option for setting curves i believe)
    And i am wondering, what is the power(kW) value used for?
    Because i believe in order to calculate speed, you only need the force parameter, not the power.
    So what does power actually mean, and what is it used for in MSTS?


    Thanks

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    Are the respondents to the thread acting as independent contractors, or paid consultants?
    Cheers, R. Steele [Gerry] It's my railroad and I'll do what I want! Historically accurate attitude of US Railroad Barons.


  8. #8

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    How do you mean?

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    Good point. There a bit of an excess of irrational exuberance and a lack of good old research and development.
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  10. #10
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    Quote Originally Posted by timl132 View Post
    I see, so an eelctric train will provide somewath constant power most of the time, but what about force?
    How is that caluclated in MSTS?(as it doesn't seem to have a option for setting curves i believe)
    And i am wondering, what is the power(kW) value used for?
    Because i believe in order to calculate speed, you only need the force parameter, not the power.
    So what does power actually mean, and what is it used for in MSTS?


    Thanks
    Power provides the force. No power=no move.
    Beer is not a matter of life or death, it is much more serious than that.

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