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In the file library there is a chart that lists the grades vs. elevation. Don't have the file name on hand but I would imagine it is in the misc. section. Jae
Confusingly, the grade is specified in the "elevation" box, which is in degrees. To get the grade (%) from degrees, take the sin of the degrees. To get the degrees from a grade, take the inverse sin. Be sure you enter the grade as 0.01 for 1%, etc, and be sure your calculator is set for degrees, not radians or gradians.For example, if you want a grade of 1%, it would be 0.573 degrees. You can adjust the "elevation" in 0.150 increments using the mouse, and 0.001 or 0.002 increments by holding down the end key and using the arrows on the numeric keypad.Mark
This is probably more than you wanted to know, but this was in the archives that are now missing .. and at the bottom are some numbers for us math-challenged people ------------Please forgive me if you guys know this already. When you set the grade on the piece of track, the number you set is in degrees of angle, not grade percent. For example, a value of 1.500 in the elevation window is not 1.5 percent, it's 1.5 degrees from horizontal, which equals a 2.6 percent grade.Tangent and Arc-Tangent are used to convert between the two. If you have a scientific calculator it's very simple. Make sure the calculator is set to Degrees (most have a degrees/radians/gradians button labeled DRG).To convert degrees to percent: (1.5 degrees as an example) 1) Enter the number of degrees in the elevation window 2) Hit the TAN (tangent) button 3) Multiply the resulting number by 100 1.5(TAN) x 100 = 2.618 Percent Grade To convert percent to degrees: (3 percent grade as an example) 1) Enter the grade in percent 2) Divide grade by 100 3) Hit Arc-Tangent (tan-1). Some people will need to hit the shift or second-function button. On my calculator, I hit (2ndF) and then the (TAN) button.3.0 / 100 then (ArcTangent) = 1.718 Degrees (make sure you have 0.03 BEFORE hitting Arc-Tangent)Here's some conversions for those who don't like trigonometry: Percent : Degrees 0.5% = 0.2864 1.0% = 0.5729 1.5% = 0.8593 2.0% = 1.1457 2.5% = 1.4320 3.0% = 1.7183 5.2% = 3.0000 (max number the sim will allow for track!) I had laid alot of track up and down hill before I realized this!John Greenstone 3dTrainstuff.com
Ok, forget all that garbage about sins, sinners, tan beds etc....This method is for the mathematically challenged. It's really a simple formula, and I've posted it many times before but here it is again:slope = vertical rise/horizontal runThat is, if your track rises 1m in 100m of run (1/100), then your result is .01 or a 1% grade. Wasn't that easy?So if track piece A has a "y" coordinate of lets say 286.75, and you have a 250m piece of track that is sloped up and you want to find out what the percent grade is. You will have to attach another piece of track to the end of the piece you want to measure to use the "y" coordinate for that piece. Lets say that the piece AFTER the 250m has a "y" coordinate of 288.25. Take that number and subtract the "y" number from the other end (288.25-286.75=1.5), take that value (vertical rise) and divide it by 250 (horizontal run) to get your grade. (1.5/250 = .006 or .6% grade).You could make your own grade chart using 100m track pieces and going by the standard .15 degree increments that you get when you elevate the end of a piece of track, compute the percentage slope for every .15 degree.You could also use the inverse if you have a specific slope you want to model. Lets say you want to model a prototypical 2.5% slope. You would have to know the horizontal run, lets use an example of 1000m. You know that a 10m rise in 1000m is 1%, so 25m rise in 1000m would be 2.5% (formula for inverse is (1000)(.025) = 25)Be aware that my formula is an AVERAGE slope. You can have varying degrees of slope within that 1000m by sloping 10 100m sections different degrees of slope within that 1000m. Modelling a prototypical slope would be much easier if you had the slope chart to know how many degrees equals what percentage slope.Confused yet?Jeff Leslie
You guys with your complicated trig formulas give me heartburn.One degree is a one point seventy-five percent grade. No need for scientific calculators or charts, degrees times 1.75 = grade, grade divided by 1.75 = degrees. Try that with the charts, it comes out to within a few hundred thousandths every time.
I agree with most all of the above, but I will also point out that if you have the track charts or other engineering data for the track you are duplicating, there will be many variations due to compensation for curves in the real world. You cannot easily do that in MSTS and in any case, I have not seen where MSTS recognizes curve effects anyway. Therefore, I just take the elevations at the end points of a distance of track if I can figure them from a topo. map, and figure the grade, i.e. the average grade to get that variation. You can also average the grade over a distance if you have the charts and use that value. There is one caviat though -- Dynamic track. Curves in dynamic track do not compute elevation around the curve, or even across an arc, rather they take it radially from beginning to end, which may result in a much steeper grade (and a guaranteed uncoupling) if you attempt to extend a grade around too long a curve. If my curve is steeper than about .2 Gradient, i.e. "elevation", then I limit my arc swings to no more than .5, and put 10m straight pieces in between. Not sure if the latter is required, but it has been recommended.J. H. Sullivan, P.E. (retired)
I definitely have noticed the effect of cars going around curves, in that it slows down the train because of the resistance of the curve. It is a lot more noticeable with sharp curves, like 12 and 16 degrees.Right you are about dynamic track. I have minimized the problem by limiting my arc swings to 0.200 radians, but with no straight sections in between. I developed a little formuala in Excel that takes the grade you want, and then adjusts it to work with whatever arc swing I'm using. Usually for a 0.200 radian arc, it's only a difference of 0.003 - 0.004 degrees in the "elevation" box, but over time this little difference can add up, especially when using large radius curves. This has worked fine, even with curves that turn over 180 degrees, and I usually end up within 3 or 4 inches of my desired elevation, i.e. height above sea level, in this case.Having said this, I usually just average the grade over a length of track anyway, whereas on the track chart, there are many varying grades, I'll just stick with an average, which makes for easier track laying.MarkMoffat Road Tabernash to Craig (52% of track laid)
